Comments Off on Hyperchloraemia and mortality
Here’s something to add to the pile of data cautioning us to think before we acidify patients with saline. A study in Anesthesia and Analgesia using propensity matching provides retrospective evidence that patients who developed hyperchloremia after noncardiac surgery had worse outcomes.
For more information on why saline isn’t ‘normal’ see: What’s with all the chloride? An assault on salt
Hyperchloremia after noncardiac surgery is independently associated with increased morbidity and mortality: a propensity-matched cohort study
Anesth Analg. 2013 Aug;117(2):412-21
BACKGROUND: The use of normal saline is associated with hyperchloremic metabolic acidosis. In this study, we sought to determine the incidence of acute postoperative hyperchloremia (serum chloride >110 mEq/L) and whether this electrolyte disturbance is associated with an increase in length of hospital stay, morbidity, or 30-day postoperative mortality.
METHODS: Data were retrospectively collected on consecutive adult patients (>18 years of age) who underwent inpatient, noncardiac, nontransplant surgery between January 1, 2003 and December 31, 2008. The impact of postoperative hyperchloremia on patient morbidity and length of hospital stay was examined using propensity-matched and logistic multivariable analysis.
RESULTS: The dataset consisted of 22,851 surgical patients with normal preoperative serum chloride concentration and renal function. Acute postoperative hyperchloremia (serum chloride >110 mmol/L) is quite common, with an incidence of 22%. Patients were propensity-matched based on their likelihood to develop acute postoperative hyperchloremia. Of the 4955 patients with hyperchloremia after surgery, 4266 (85%) patients were matched to patients who had normal serum chloride levels after surgery. These 2 groups were well balanced with respect to all variables collected. The hyperchloremic group was at increased risk of mortality at 30 days postoperatively (3.0% vs 1.9%; odds ratio = 1.58; 95% confidence interval, 1.25-1.98) (relative risk 1.6 or risk increase of 1.1%) and had a longer hospital stay (7.0 days [interquartile range 4.1-12.3] compared with 6.3 [interquartile range 4.0-11.3]) than patients with normal postoperative serum chloride levels. Patients with postoperative hyperchloremia were more likely to have postoperative renal dysfunction. Using all preoperative variables and measured outcome variables in a logistic regression analysis, hyperchloremia remained an independent predictor of 30-day mortality with an odds ratio of 2.05 (95% confidence interval, 1.62-2.59).
CONCLUSION: This retrospective cohort trial demonstrates an association between hyperchloremia and poor postoperative outcome. Additional studies are required to demonstrate a causal relationship between these variables.
Comments Off on What happened to HIFU?
High intensity focused ultrasound (HIFU) was hailed as the ‘surgery of the future’ a few years ago(1). As it’s now the future, where is it?
HIFU uses ultrasound to increase the heat within tissues at a specific area, causing local necrosis and cautery without injuring surrounding tissues. It is used to treat some cancers, but has shown promise in haemorrhage control. In animal studies it reduced or stopped bleeding in liver(2), spleen(3), and vascular injuries(4).
It has been proposed to offer a promising method for hemorrhage control in both civilivan and miltary trauma(5). Automated systems have been developed and tested that identify bleeding using Doppler ultrasound techniques that then allow targeting of the HIFU beam to the bleeding tissue(6). The United States Army has identified the need for a such systems and has designed a remotely operated robotic haemostatic system to save lives of soldiers. This was presented in 2006(7).
I would love to know where we are with this technology, and why nothing seems to have appeared about it in the literature for the last few years. If you have any information, please fill us in via the comments box.
1. High intensity focused ultrasound: surgery of the future?
Br J Radiol. 2003 Sep;76(909):590-9 Full text
2. Liver hemostasis using high-intensity focused ultrasound
Ultrasound Med Biol. 1997;23(9):1413-20
3. Control of splenic bleeding by using high intensity ultrasound
J Trauma. 1999 Sep;47(3):521-5
4. Hemostasis of punctured blood vessels using high-intensity focused ultrasound
Ultrasound Med Biol. 1998 Jul;24(6):903-10
5. Hemorrhage control using high intensity focused ultrasound
Int J Hyperthermia. 2007 Mar;23(2):203-11
6. Focused ultrasound: concept for automated transcutaneous control of hemorrhage in austere settings.
Aviat Space Environ Med. 2009 Apr;80(4):391-4
7. Remotely Operated Robotic High Intensity Focused Ultrasound (HIFU) Manipulator System for Critical Systems for Trauma and Transport (CSTAT)
Presented at the IEEE Ultrasonics Symposium, October 3-6, 2006, Vancouver, Canada – Full Text Here
“To date, approximately one-third of the women who die during pregnancy remain undelivered at the time of death”
Guidelines recommend cardiac arrest in pregnant women beyond 20 weeks gestation should be treated with perimortem caesarean delivery (PMCD) commenced within 4 minutes of arrest and completed within 5. These time intervals come from two papers, neither of which is current or used robust review methodology.
To address this, an up-to-date fairly comprehensive review was undertaken of published cases of maternal cardiac arrests occurring prior to delivery. The primary outcome measures were maternal and neonatal survival to hospital discharge and the relationship between PMCD and this outcome.
94 cases were included in the final analysis.Most pregnancies were singleton (90.4%, n = 85) with an average gestational age at the time of the arrest of 33 ± 7 weeks (median 35, range 10–42).
The most common causes of arrest were trauma, maternal cardiac problems, severe pre-eclampsia and amniotic fluid embolism, together comprising about 70% of arrests; two thirds occurred in hospital.
Overall, return of spontaneous circulation (ROSC) was achieved more often than not (60.6%) and overall survival to hospital discharge was 54.3%
Only 57 cases (75%) reported the time from arrest to delivery; the average time was 16.6 ± 12.5 min (median 10, range 1–60), with only 4 cases making it under the advocated 4-min time limit.
Timing of PMCD and Maternal Survival
In cases undergoing PMCD the average time elapsing from arrest to PMCD was significantly different between surviving (27/57) and non-surviving (30/57) mothers [10.0 ± 7.2 min (median 9, range 1–37) and 22.6 ± 13.3 min (median 20, range 4–60) respectively (p < 0.001, 95%CI 6.9–18.2)].
Timing of PMCD and Neonatal Survival
Mean times to PMCD were 14±11min (median=10, range=1–47) and 22 ± 13 min (median = 20, range = 4–60) in neonatal survivors and non-survivors respectively (p=0.016)
In cases with PMCD which reported outcome, the overall neonatal survival rate was 63.6% (42/66).
“The 4-min time frame advocated for PMCD usually remains unmet yet neonatal survival is still likely if delivery occurs within 10 or even 15 min of arrest”
Both maternal & neonatal mortality were higher with prehospital arrest location.
The study may be limited by recall bias, under-reporting and publication bias, but provides a more comprehensive evidence base on which to base resuscitation recommendations. The authors provide a useful warning against becoming fixated with the recommended four minute window, which may lead teams to fail to attempt a potentially life-saving intervention:
“Fixation on specific time frames for PMCD may not be ideal. It may be more important to focus on event recognition and good overall performance…. It may be wise to advocate a short time frame for performance of PMCD in order to achieve better outcomes; however, blanket endorsement of an unrealistic time frame may well create a defeatist attitude when that time frame cannot be met.”
Maternal cardiac arrest and perimortem caesarean delivery: Evidence or expert-based?
Resuscitation. 2012 Oct;83(10):1191-200
AIM: To examine the outcomes of maternal cardiac arrest and the evidence for the 4-min time frame from arrest to perimortem caesarean delivery (PMCD) recommended in current resuscitation and obstetric guidelines.
DATA SOURCES AND METHODS: Review and data extraction from all reported maternal cardiac arrests occurring prior to delivery (1980-2010). Cases were included if they provided details regarding both the event and outcomes. Outcomes of arrest were assessed using survival, Cerebral Performance Category (CPC) and maternal/neonatal harm/benefit from PMCD. Outcome measures were maternal and neonatal survival.
RESULTS: Of 1594 manuscripts screened, 156 underwent full review. Data extracted from 80 relevant papers yielded 94 included cases. Maternal outcome: 54.3% (51/94) of mothers survived to hospital discharge, 78.4% (40/51) with a CPC of 1/2. PMCD was determined to have been beneficial to the mother in 31.7% of cases and was not harmful in any case. In-hospital arrest and PMCD within 10 min of arrest were associated with better maternal outcomes (ORs 5.17 and 7.42 respectively, p<0.05 both). Neonatal outcome: mean times from arrest to delivery were 14±11 min and 22±13 min in survivors and non-survivors respectively (receiver operating area under the curve 0.729). Neonatal survival was only associated with in-hospital maternal arrest (OR 13.0, p<0.001).
CONCLUSIONS: Treatment recommendations should include a low admission threshold to a highly monitored area for pregnant women with cardiorespiratory decompensation, good overall performance of resuscitation and delivery within 10 min of arrest. Cognitive dissonance may delay both situation recognition and the response to maternal collapse.
The highlight for me was Mr Jonny Morrison speaking on Resuscitative Emergency Balloon Occlusion of the Aorta (REBOA). He is a British military surgeon currently out in Texas studying balloon occlusion of the aorta on pigs. Looking at trauma deaths, the next unexpected survivors will come from the uncontrollable haemorrhage group (truncal and junctional zones). This is by no means a new technique – described in the 1950’s during the Korean War – but like the early Star Wars chapters, needed to wait for technology to advance to make it feasible. It has the effect of cross clamping the aorta which provides afterload support, increases cerebral and coronary perfusion and provides proximal inflow control – without the mess of a resuscitative thoracotomy and greater access.
The placement of the balloon is determined by the location of the injury (see photo) and falls into two zones. Zone 1 is the thoracic aorta and is used for truncal haemorrhage control, avoid Zone 2 where the celiac axis etc originates and Zone 3 is infrarenal, used for junctional bleeding and pelvic haemorrhage.
His studies have determined that for Zone 3 amenable bleeds balloon occlusion up to 60min is the optimal time. Any longer and the debt of the metabolic load is paid by increased inotropic support requirements. He also compared REBOA to the current standard treatment for junctional injuries, Celox™ gauze. If coagulation is normal then both treatments perform similarly, the benefit is seen in coagulopathic patients where REBOA outperforms the gauze.
Has REBOA been used on humans? Yes a case series of 13 – the technique improved the BP allowing time to get to definitive surgery (blogged here 2.5 years ago!).
The Zone 1 studies are looking at continuous vs intermittent balloon occlusion. The jury is still out as to which is better. With the intermittent occlusion (20min on, 1min off) there are inevitably some losses when the balloon is deflated, conversely the metabolic debt generated by continuous occlusion is too great in some also leading to deaths.
What was very clear is that for this technique to have an impact it must be delivered proactively and pre-hospital. The challenges that need to be overcome are access to the femoral artery and blind accurate placement.
Prof Karim Brohi brought the conference to a close with a summary of what we have learned about coagulation in trauma this year. Here are three things;
- FFP is good but as 43% deaths due to trauma in the UK are secondary to bleeding and occur in the first 3hr we are failing our patients by administering the treatment on average at 2.5hrs.
- Fibrinogen levels are low in coagulopathic trauma patients; we should give cryoprecipitate early and aim for Fib ≥2.0
- And finally whilst TEG is recommended to guide treatment and can provide results within 5 min, there are some aspects of coagulation it does not detect i.e. fibrinolysis was only detected in 8% of coagulopathic trauma patients – when measured in the plasma it was then detectable in 80%.
These are the highlights of the 2012 London Trauma Conference. I hope this whistle stop tour through these days has been informative and though provoking. I can assure you telephone hacking was not used to bring you this information and to my knowledge is correct.
This is Lou Chan, roving reporter for Resus ME! signing off.
‘London raises her head, shakes off the debris of the night from her hair, and takes stock of the damage done. The sign of a great fighter in the ring is can he get up from a fall after being knocked down… London does this every morning.’
Comments Off on Transtracheal airways in kids. Well, pigs’ kids anyway
Ever had to do a surgical airway in a child? Thought not. They’re pretty rare. Bill Heegaard MD from Henepin County Medical Center taught me a few approaches (with the help of an anaesthetised rabbit) which really got me thinking. It’s something I’d often trained for in my internal simulator, and I even keep the equipment for it in my house (listen out for an upcoming podcast on that). Research and experience has demonstrated that open surgical airway techniques are more reliable than transtracheal needle techniques in adults, but what about kids, in whom traditional teaching cautions against open techniques?
Australian investigators who were experienced airway proceduralists evaluated transtracheal needle techniques using a rabbit model (an excellent model for the infant airway). Their success rate was only 60% and they perforated the posterior tracheal wall in 42% of attempts. Of 13 attempts to insert a dedicated paediatric tracheotomy device, the Quicktrach Child, none were successful(1) (they did not use the Quicktrach Infant model as it is not available in Australia).
Danish investigators used fresh piglet cadavers weighing around 8 kg to assess two transtracheal cannulas, in which they achieved success rates of 65.6% and 68.8%(2). There was also a very high rate of posterior tracheal wall perforation. Using an open surgical tracheostomy technique, they were successful in 97% of attempts. These were also experienced operators, with a median anaesthetic experience of 12.5 years.
Their tracheotomy technique was nice and simple, and used just a scalpel, scissors, and surgical towel clips. Here’s their technique:
Simple tracheotomy procedure described by Holm-Knudsen et al
- Identify larynx and proximal trachea by palpation
- Vertical incision through the skin and subcutaneous tissue from the upper part of larynx to the sternal notch
- Grasp strap muscles with two towel forceps and separate in the midline
- Palpate and identify the trachea (palpate rather than look for tracheal rings, as in a live patient one would expect bleeding to obscure the view)
- Stabilise the trachea by grasping it with a towel forceps
- Insert sharp tip of the scissors between two tracheal rings and lift the trachea anteriorly to avoid damage to the posterior wall
- Cut vertically in the midline of the trachea with the scissors – they chose to use the scissors to cut the tracheal rings to facilitate tube insertion
- Insert the tracheal tube
Using ultrasound and CT to evaluate comparative airway dimensions, the authors concluded that the pig model is most useful for training emergency airway management in older children aged 5–10 years.
Why were they doing a tracheotomy rather than a cricothyroidotomy? Reasons given by the authors include:
- The infant cricothyroid membrane is very small
- Palpation of the thyroid notch may be hindered by the overlying hyoid bone
- The mandible may obstruct needle access to the cricothyroid membrane given the cephalad position in the neck of the infant larynx.
From an emergency medicine point of view, there are a couple of other reasons why we need to be able to access the trachea lower than the cricothyroid membrane. One is fractured larynx or other blunt or penetrating airway injury where there may be anatomical disruption at the cricothyroid level. The other situation is foreign body airway obstruction, when objects may lodge at the level of the cricoid ring which is functionally the narrowest part of the pediatric upper airway. Of course, alternative methods might be considered to remove the foreign body prior to tracheotomy, such as employing basic choking algorithms, and other techniques depending on whether you do or don’t have equipment.
Take home messages
- Transtracheal airways in kids are so rare, we can’t avoid extrapolating animal data
- Whichever infant or paediatric model is used, transtracheal needle techniques have a high rate of failure even by ‘experienced’ operators
- The small size and easy compressibility of the airway probably contributes to this failure rate, including the high rate of posterior wall puncture
- In keeping with adult audit data, open surgical techniques may have a higher success rate
- Tracheotomy may be necessary rather than cricothyroidotomy in infants and children depending on clinical scenario and accessibility of anatomy
- The stress and blood that is not simulated in cadaveric animal models will make open tracheotomy harder in a live patient, and so these success rates may not translate. However these factors do mean that whatever technique is used must be kept simple and should employ readily available and familiar equipment
- Something to maintain control and anterior position of the anterior trachea wall should be used during incision and intubation of the trachea. The study reported here used towel clips; sutures around the tracheal rings may also be used (see image below)
I recommend you add ‘paediatric tracheotomy’ to the list of procedures you might need to do (if it’s not already there). Identify what equipment you would use and run the simulation in your head and in your work environment.
Paediatr Anaesth. 2012 Dec;22(12):1155-8
BACKGROUND: Little evidence exists to guide the management of the ‘Can’t Intubate, Can’t Oxygenate’ (CICO) scenario in pediatric anesthesia.
OBJECTIVES: To compare two intravenous cannulae for ease of use, success rate and complication rate in needle tracheotomy in a postmortem animal model of the infant airway, and trial a commercially available device using the same model.
METHODS: Two experienced proceduralists repeatedly attempted cannula tracheotomy in five postmortem rabbits, alternately using 18-gauge (18G) and 14-gauge (14G) BD Insyte(™) cannulae (BD, Franklin Lakes, NJ, USA). Attempts began at the first tracheal cartilage, with subsequent attempts progressively more caudad. Success was defined as intratracheal cannula placement. In each rabbit, an attempt was then made by each proceduralist to perform a cannula tracheotomy using the Quicktrach Child(™) device (VBM Medizintechnik GmbH, Sulz am Neckar, Germany).
RESULTS: The rabbit tracheas were of similar dimensions to a human infant. 60 attempts were made at cannula tracheotomy, yielding a 60% success rate. There was no significant difference in success rate, ease of use, or complication rate between cannulae of different gauge. Successful aspiration was highly predictive (positive predictive value 97%) and both sensitive (89%) and specific (96%) for tracheal cannulation. The posterior tracheal wall was perforated in 42% of tracheal punctures. None of 13 attempts using the Quicktrach Child(™) were successful.
CONCLUSION: Cannula tracheotomy in a model comparable to the infant airway is difficult and not without complication. Cannulae of 14- and 18-gauge appear to offer similar performance. Successful aspiration is the key predictor of appropriate cannula placement. The Quicktrach Child was not used successfully in this model. Further work is required to compare possible management strategies for the CICO scenario.
2. Emergency airway access in children – transtracheal cannulas and tracheotomy assessed in a porcine model
Paediatr Anaesth. 2012 Dec;22(12):1159-65
OBJECTIVES: In the rare scenario when it is impossible to oxygenate or intubate a child, no evidence exists on what strategy to follow.
AIM: The aim of this study was to compare the time and success rate when using two different transtracheal needle techniques and also to measure the success rate and time when performing an emergency tracheotomy in a piglet cadaver model.
METHODS: In this randomized cross-over study, we included 32 anesthesiologists who each inserted two transtracheal cannulas (TTC) using a jet ventilation catheter and an intravenous catheter in a piglet model. Second, they performed an emergency tracheotomy. A maximum of 2 and 4 min were allowed for the procedures, respectively. The TTC procedures were recorded using a video scope.
RESULTS: Placement of a transtracheal cannula was successful in 65.6% and 68.8% of the attempts (P = 0.76), and the median duration of the attempts was 69 and 42 s (P = 0.32), using the jet ventilation catheter and the intravenous catheter, respectively. Complications were frequent in both groups, especially perforation of the posterior tracheal wall. Performing an emergency tracheotomy was successful in 97%, in a median of 88 s.
CONCLUSIONS: In a piglet model, we found no significant difference in success rates or time to insert a jet ventilation cannula or an intravenous catheter transtracheally, but the incidence of complications was high. In the same model, we found a 97% success rate for performing an emergency tracheotomy within 4 min with a low rate of complications.
Comments Off on A whole bunch of trauma guidelines
The Eastern Association for the Surgery of Trauma has published a number of helpful evidence-based guidelines for trauma management, and many of them are included in this month’s Journal of Trauma and Acute Care Surgery
Here are brief snippets from some of them. All the guidelines can be viewed or downloaded in full for free here.
Nonoperative management of blunt hepatic injury
- Nonoperative management of blunt hepatic injuries currently is the treatment modality of choice in hemodynamically stable patients, irrespective of the grade of injury or patient age.
- Patients presenting with hemodynamic instability and peritonitis still warrant emergent operative intervention.
- Intravenous contrast enhanced computed tomographic scan is the diagnostic modality of choice for evaluating blunt hepatic injuries.
Selective nonoperative management of blunt splenic injury
- Nonoperative management of blunt splenic injuries is now the treatment modality of choice in hemodynamically stable patients, irrespective of the grade of injury, patient age, or the presence of associated injuries.
- Patients presenting with hemodynamic instability and peritonitis still warrant emergent operative intervention.
- Intravenous contrast enhanced computed tomographic scan is the diagnostic modality of choice for evaluating blunt splenic injuries.
Screening for blunt cardiac injury
- Electrocardiogram (ECG) alone is not sufficient to rule out BCI.
- BCI can be ruled out only if both ECG result and troponin I level are normal, a significant change from the previous guideline.
- Patients with new ECG changes and/or elevated troponin I should be admitted for monitoring.
- Echocardiogram is not beneficial as a screening tool for BCI and should be reserved for patients with hypotension and/or arrhythmias.
- The presence of a sternal fracture alone does not predict BCI.
- Cardiac computed tomography or magnetic resonance imaging can be used to differentiate acute myocardial infarction from BCI in trauma patients.
Evaluation and management of penetrating lower extremity arterial trauma
- Expedited triage of patients is possible with physical examination and/or the measurement of ankle-brachial indices.
- Computed tomographic angiography has become the diagnostic study of choice when imaging is required.
- Tourniquets and intravascular shunts have emerged as adjuncts in the treatment of penetrating lower extremity arterial trauma.
Prophylactic antibiotic use in penetrating abdominal trauma
- There is evidence to support a Level I recommendation that prophylactic antibiotics should only be administered for 24 hours in the presence of a hollow viscus injury.
- There are no data to support continuing prophylactic antibiotics longer than 24 hours in damage control laparotomy.
Screening for thoracolumbar spinal injuries in blunt trauma
- Multidetector computed tomographic scans have become the screening modality of choice and the criterion standard in screening for TLS injuries.
- Patients without altered mentation or significant mechanism may be excluded by clinical examination without imaging.
- Patients with gross neurologic deficits or concerning clinical examination findings with negative imaging should receive a magnetic resonance imaging expediently, and the spine service should be consulted
Emergency tracheal intubation immediately following traumatic injury
- The decision to intubate a patient following traumatic injury is based on multiple factors, including the need for oxygenation and ventilation, the extent and mechanism of injury, predicted operative need, or progression of disease.
- Rapid sequence intubation with direct laryngoscopy continues to be the recommended method for ETI, although the use of airway adjuncts such as blind insertion supraglottic devices and video laryngoscopy may be useful in facilitating successful ETI and may be preferred in certain patient populations.
- There is no pharmacologic induction agent of choice for ETI; however, succinylcholine is the neuromuscular blockade agent recommended for rapid sequence intubation.
Presumptive antibiotic use in tube thoracostomy for traumatic hemopneumothorax
- Routine presumptive antibiotic use to reduce the incidence of empyema and pneumonia in TT for traumatic hemopneumothorax is controversial; however, there is insufficient published evidence to support any recommendation either for or against this practice.
Evaluation and management of geriatric trauma
- Effective evidence-based care of aging patients necessitates aggressive triage, correction of coagulopathy, and limitation of care when clinical evidence points toward an overwhelming likelihood of poor long-term prognosis
Management of pulmonary contusion and flail chest
- Patients with PC-FC should not be excessively fluid restricted but should be resuscitated to maintain signs of adequate tissue perfusion.
- Obligatory mechanical ventilation in the absence of respiratory failure should be avoided.
- The use of optimal analgesia and aggressive chest physiotherapy should be applied to minimize the likelihood of respiratory failure.
- Epidural catheter is the preferred mode of analgesia delivery in severe flail chest injury.
- Paravertebral analgesia may be equivalent to epidural analgesia and may be appropriate in certain situations when epidural is contraindicated.
- A trial of mask continuous positive airway pressure should be considered in alert patients with marginal respiratory status.
- Patients requiring mechanical ventilation should be supported in a manner based on institutional and physician preference and separated from the ventilator at the earliest possible time.
- Positive end-expiratory pressure or continuous positive airway pressure should be provided.
- High-frequency oscillatory ventilation should be considered for patients failing conventional ventilatory modes. Independent lung ventilation may also be considered in severe unilateral pulmonary contusion when shunt cannot be otherwise corrected.
- Surgical fixation of flail chest may be considered in cases of severe flail chest failing to wean from the ventilator or when thoracotomy is required for other reasons.
- Self-activating multidisciplinary protocols for the treatment of chest wall injuries may improve outcome and should be considered where feasible.
- Steroids should not be used in the therapy of pulmonary contusion.
- Diuretics may be used in the setting of hydrostatic fluid overload in hemodynamically stable patients or in the setting of known concurrent congestive heart failure.
Evaluation and management of small-bowel obstruction
- Level I evidence now exists to recommend the use of computed tomographic scan, especially multidetector computed tomography with multiplanar reconstructions, in the evaluation of patients with SBO because it can provide incremental clinically relevant information over plains films that may lead to changes in management.
- Patients with evidence of generalized peritonitis, other evidence of clinical deterioration, such as fever, leukocytosis, tachycardia, metabolic acidosis, and continuous pain, or patients with evidence of ischemia on imaging should undergo timely exploration.
- The remainder of patients can safely undergo initial nonoperative management for both partial and complete SBO.
- Water-soluble contrast studies should be considered in patients who do not clinically resolve after 48 to 72 hours for both diagnostic and potential therapeutic purposes.
- Laparoscopic treatment of SBO has been demonstrated to be a viable alternative to laparotomy in selected cases.
2012 Eastern Association for the Surgery of Trauma (EAST) Practice Management Guidelines Supplement
J Trauma Acute Care Surg. 2012 Nov;73(5 Suppl 4)
Comments Off on Thoracoabdominal trauma outcomes
Most solid organ injuries in the abdomen are managed non-operatively
Thoracotomy – especially non-resuscitative thoracotomy – is rare
In patients with thoracoabdominal trauma, the overwhelming majority of injuries requiring operative intervention were found in the abdomen, therefore..
…excluding those patients in extremis requiring a resuscitative thoracotomy, the initial incision, without directive radiological information, belongs in the abdomen
Concomitant thoracic injury did not preclude nonoperative management of abdominal solid organ injury
This is a really interesting paper providing important data on the outcomes and management of a patient group that frequently produces management dilemmas in trauma centres.
The double jeopardy of blunt thoracoabdominal trauma
Arch Surg. 2012 Jun;147(6):498-504
OBJECTIVES: To examine the specific injuries, need for operative intervention, and clinical outcomes of patients with blunt thoracoabdominal trauma.
DESIGN: Trauma registry and medical record review.
SETTING: Level I trauma center in Los Angeles, California.
PATIENTS: All patients with thoracoabdominal injuries from January 1996 to December 2010.
MAIN OUTCOME MEASURES: Injuries, incidence and type of operative intervention, clinical outcomes, and risk factors for mortality.
RESULTS: Blunt thoracoabdominal injury occurred in 1661 patients. Overall, 474 (28.5%) required laparotomy, 31 (1.9%) required thoracotomy (excluding resuscitative thoracotomy), and 1146 (69.0%) required no thoracic or abdominal operation. Overall incidence of intraabdominal solid organ injury was 59.7% and hollow viscus injury, 6.0%. Blunt cardiac trauma occurred in 6.3%; major thoracic vessel injury, in 4.6%; and diaphragmatic trauma, in 6.0%. The majority of solid organ injuries were managed nonoperatively (liver, 83.9%; spleen, 68.3%; and kidney, 91.2%). Excluding patients with severe head trauma, mortality ranged from 4.5% with nonoperative management to 18.1% and 66.7% in those requiring laparotomy and dual cavitary exploration, respectively. Age 55 years or older, Injury Severity Score of 25 or more, Glasgow Coma Scale score of 8 or less, initial hypotension, massive transfusion, and liver, cardiac, or abdominal vascular trauma were all independent risk factors for mortality.
CONCLUSIONS: Most patients with blunt thoracoabdominal trauma are managed nonoperatively. The need for non-resuscitative thoracotomy or combined thoracoabdominal operation is rare. The abdomen contains the overwhelming majority of injuries requiring operative intervention and should be the initial cavity of exploration in the patient requiring emergent surgery without directive radiologic data.
A recent paper reminds us that surgery is an option in the management of massive pulmonary embolism(1), to be considered in the patient for whom thrombolysis has failed or is contraindicated. Good outcomes were produced when surgery was performed in a centre capable of cardiopulmonary bypass (6% 30-day postoperative mortality), but is surgery an option when these facilities are unavailable?
The “venous inflow occlusion” technique involves clamping the venae cavae prior to removing clot directly from the pulmonary artery and its branches after median sternotomy, and can be performed in any hospital with surgical facilities. Under normothermic conditions, speed is of the essence once cardiac arrest occurs, since the irreversible anoxic cerebral injury will occur after just a few minutes.
Clarke and Abrams wrote in the Lancet in 1972(2):
Our use of venous inflow-occlusion has given results which compare well with those obtained with extracorporeal circulation. 50% of our patients survived. All patients who had emboli removed without an episode of ventricular asystole survived surgery. Late deaths in 3 patients were from causes unrelated to pulmonary embolism, and from a further massive pulmonary embolus a week later. The technique has been applied with equal success in a major hospital fully equipped for cardiac surgery and in hospitals where resident and nursing staff had no experience of either thoracic or cardiac surgery. The simplicity and speed of the method has enabled the obstructed right ventricle to be relieved within thirty minutes of the onset of symptoms. The interval between induction of anaesthesia and the skin incision should be kept as short as possible, and drugs to maintain the blood pressure should be given. The period between skin incision and the restoration of the circulation has, with practice, been reduced to ten minutes.
But this clearly still requires surgical expertise and facilities. Emergency physicians can open the chest to deal with penetrating trauma. Could an ED thoracotomy facilitate clot removal from the pulmonary artery?
In 1969, a lady in her 50s arrested on the ward after an operation to remove a mass via a left lateral thoractomy. Pulmonary embolism was suspected and her thoracotomy wound was re-opened and the pulmonary artery incised, resulting in the removal of large amounts of clot. Return of spontaneous circulation resulted after a brief period of internal cardiac massage. Her case was written up decades later, in 1998(3):
The patient recovered rapidly and left the hospital on the 21st day without signs of cerebral damage. This patient is now 86 years old, mentally normal, living alone, and doing her own housekeeping. She remembers the hospital stay and the past years as worth living
Some patients may be considered too high risk for surgery and in some centres Extracorporeal Membrane Oxygenation (ECMO) is an option. It has been used both as life support pending surgery(4), or as an alternative to surgery to allow heparinisation to be used(5,6).
In summary, some patients with massive pulmonary embolism may benefit from surgery (contraindication to ‘lysis or failed ‘lysis). Getting them to surgery alive, or operating on them during cardiac arrest, is a challenge. Ideally they would undergo embolectomy under cardopulmonary bypass in the operating room, or could be placed on ECMO in the ED prior to going to the OR. If they present to a centre without these facilities, then the venous inflow occlusion technique could be used in the OR without bypass. Just rarely a patient may present in extremis with PE to an ED without these options. If that patient has major contraindications to thrombolysis, would an ED thoracotomy be something you would entertain?
I have done several thoracotomies for penetrating trauma but never for PE. I do not pretend to know how, and cannot find a case report of ED thoracotomy for pulmonary embolism in the literature. I’m therefore NOT recommending it. However, I would love to know people’s views on its feasibility. A possible approach could be summarised as:
Massive pulmonary embolism fascinates me, because it’s seen in the ‘talk and die’ patient. It is a single, treatable pathology that if diagnosed and treated appropriately truly makes the difference between life and death. When medicine presents us with an opportunity ‘on a plate’ like that to save a life, we need to be prepared. I have had great saves with this diagnosis and sadly have seen disastrous failures to act. When the time comes, we need to ask: ‘have we explored all options?’.
1. Surgical treatment of acute pulmonary embolism–a 12-year retrospective analysis.
Scand Cardiovasc J. 2012 Jun;46(3):172-6. Epub 2012 Mar 27.
OBJECTIVES: Surgical embolectomy for acute pulmonary embolism (PE) is considered to be a high risk procedure and therefore a last treatment option. We wanted to evaluate the procedures role in modern treatment of acute PE.
DESIGN: All data on patients treated with surgical embolectomy for acute PE were retrieved from our clinical database. The mortality was extracted from the Danish mortality register.
RESULTS: From October 1998 to July 2010, 33 patients underwent surgical embolectomy. All procedures were done through a median sternotomy and extracorporeal circulation. Twenty-six patients were diagnosed with a high risk PE and 7 with an intermediate risk PE and intracardial pathology. Six patients had been insufficiently treated with thrombolysis. Thirteen patients had contraindication for thrombolysis. Six patients were brought to the operating theatre in cardiogenic shock, 8 needed ventilator support, and 1 was in cardiac arrest. The postoperative 30-day mortality was 6% and during the 12-year follow-up the cumulative survival was 80% with 4 late deaths.
CONCLUSION: Surgical pulmonary embolectomy can be performed with low mortality although the treated patients belong to the most compromised part of the PE population. The results support surgical embolectomy as a vital part of the treatment algorithm for acute PE.
2. Pulmonary embolectomy with venous inflow-occlusion.
The Lancet 1972;1(7754):767–769
Massive pulmonary emboli have been removed surgically from 26 patients. The technique of normothermic circulatory arrest by venous inflow-occlusion was used in 25 patients. 13 patients survived. There were 10 operative deaths and 3 hospital deaths. Diagnosis was based upon clinical findings supplemented by electrocardiography and a plain radiograph of the chest. Surgery was offered to patients having a pulmonary embolus sufficiently massive to produce sustained hypotension. All patients whose hearts stopped beating before the embolectomy died. 6 successful operations were performed in hospitals without facilities for cardiac surgery. The method is recommended for its simplicity.
3. Left Anterior Thoracotomy for Pulmonary Embolectomy With 29-Year Follow-up
The Annals of Thoracic Surgery 1998, 66(4):1420-1421
Pulmonary embolectomy is usually performed in cardiopulmonary bypass. In acute situations too much time can be lost in setting up and connecting the pump oxygenator; this delay can cause cerebral damage in a patient with circulatory arrest. In such a situation left anterior thoracotomy can provide an ideal approach. An emergency thoracotomy can be performed in a few seconds. The lung automatically retracts. The phrenic nerve, pulmonary artery, and pericardium are clearly seen, and they outline the area for embolectomy. A case in which such an approach was successfully used is described.
4.ECMO treatment saved life of a young woman with acute pulmonary embolism
Lakartidningen 2004, 101(44):3420-3421
A 42-year old obese female using contraceptive medication was admitted to the emergency room because of sudden onset of dyspnoea and hypoxia. Computed tomography showed massive pulmonary emboli. Despite initial treatment with thrombolysis her condition deteriorated further and she was referred for acute surgery to our clinic. Before putting the patient to sleep extracorporeal circulation was instituted with access from the groin. After anaesthesia a median sternotomy was performed. With the heart beating, the main pulmonary artery was incised and a 9 cm long thrombus was removed. Immediate weaning from the heart-lung machine was not possible, mainly because of bleeding to the airways. The right atrium and the aorta was therefore cannulated and an extracorporeal circulation membrane oxygenator (ECMO) was used for three days. The patient required several re-entries for bleeding and a tracheotomy during the postoperative course. She was fully recovered three months after the operation.
5. Extracorporeal membrane oxygenator for pulmonary embolism.
The Annals of Thoracic Surgery 1997, 64(3):883-884 Free full text
6. Peripheral Extracorporeal Membrane Oxygenation: Comprehensive Therapy for High-Risk Massive Pulmonary Embolism
Ann Thorac Surg 2012;94:104–8
Background: Although commonly reserved as a last line of defense, experienced centers have reported excellent results with pulmonary embolectomy for massive and submassive pulmonary embolism (PE). We present a contemporary surgical series for PE that demonstrates the utility of peripheral extracorporeal membrane oxygenation (pECMO) for high-risk surgical candidates.
Methods: Between June 2005 and April 2011, 29 patients were treated for massive or submassive pulmonary embolism, with surgical embolectomy performed in 26. Four high-risk patients were placed on pECMO, established by percutaneously cannulating the right atrium through a femoral vein and perfusing by a Dacron graft anastomosed to the axillary artery. A small, extracorporeal, rotary assist device was used, interposing a compact oxygenator in the circuit, and maintaining anticoagulation with heparin.
Results: Extracorporeal membrane oxygenation was weaned in 3 of 4 patients after 5.3 days (5, 5, and 6), with normalization of right ventricular dysfunction and pulmonary artery pressure (44.0 ± 2.0 to 24.5 ± 5.5 mm Hg) by ECHO. Follow-up computed tomographies showed several peripheral, nearly resorbed emboli in 1 case and complete resolution in 2 others. The fourth patient, not improving after 10 days, underwent surgery where an embolic liposarcoma was extracted. For all 29 cases, hospital and 30-day mortality was 0% and all patients were discharged, with average postoperative length of stay of 15 days for embolectomy and 17 days for pECMO.
Conclusions: Heparin therapy with pECMO support is a rapid, effective option for patients who might benefit from pulmonary embolectomy but are at high risk for surgery.
by Dr Cliff Reid FCEM, and Dr Mike Clancy FCEM
This article is to be published in Emergency Medicine Journal (EMJ), and is reproduced here with permission of the BMJ Group.
Some procedures that fit this description, such as tracheal intubation after neuromuscular blockade in a hypoxaemic patient with trismus, or placement of an intercostal catheter in a patient with a tension pneumothorax, are required sufficiently frequently in elective clinical practice that competence can be acquired simply by training in emergency department, intensive care, or operating room environments.
Other procedures, such as resuscitative thoracotomy, may be required so infrequently that the first time a clinician encounters a patient requiring such an intervention may be after the completion of specialist training, or in the absence of colleagues with prior experience in the technique.
Some techniques that might be considered limb or life saving may be too technically complex to acquire outside specialist surgical training programs. Examples are damage control laparotomy and limb fasciotomy. One could however argue that these are rarely too urgent to await arrival of the appropriate specialist.
The procedures which might fit the description of a time‐critical life, limb, or sight saving procedure in which it is technically feasible to acquire competence within or alongside an emergency medicine residency, and that cannot await another specialist, include:
- thoracotomy for penetrating traumatic arrest;
- hysterotomy for maternal cardiac arrest;
- surgical airway for a can’t intubate, can’t oxygenate situation;
- limb amputation for the entrapped casualty with life-threatening injuries;
- escharotomy for a burns patient with compromised ventilation or limb perfusion;
- and lateral canthotomy for retrobulbar haemorrhage with orbital compartment syndrome.
Defining competence for emergency physicians
A major challenge is the acquisition of competence in the face of such clinical rarity. One medical definition of competence is ‘the knowledge, skill, attitude or combination of these, that enables one to effectively perform the activities of a particular occupation or role to the standards expected’; in essence the ability to perform to a standard, but where are these standards defined?
If we look to the curricula which are used to assess specialist emergency physicians in several English-speaking nations, all the procedures in the short list above are included, although no one single nation’s curriculum includes the entire list (Table 1).
So an emergency physician is expected to be able to conduct these procedures, and a competent emergency physician effectively performs them to the ‘standards’ expected. It appears then that the question is not whether emergency physicians should perform them, but to what standard should they be trained? Only then can the optimal approach to training be decided.
There are convincing arguments that even after minimal training the performance of these procedures by emergency physicians is justifiable:
- All the abovementioned interventions could be considered to carry 100% morbidity or mortality if not performed, with some chance of benefit whose magnitude depends on the timeliness of intervention. In some cases that risk is quantifiable: cardiac arrest due to penetrating thoracic trauma has 100% mortality if untreated, but an 18% survival to discharge rate, with a high rate of neurologically intact survivors, if performed by prehospital emergency medicine doctors in the field according to defined indications and using a simple operative procedure. In this extreme clinical example, no further harm to the patient can result from the procedure but a chance of supreme benefit exists. Thus, the ethical requirements of beneficence and non-maleficence are both met even in the circumstance of very limited training for the procedure. It is hard to conceive of many other circumstances in medicine where the benefit:harm ratio approaches infinity.
- The procedures in question are technically straightforward and can be executed without specialist equipment in non-operating room environments. These factors appear to be underappreciated by non-emergency specialist opponents of emergency physician-provided thoracotomy whose practice and experience is likely to be predominantly operating room-based.
- Some of the procedures are recommended or mandated by official guidelines, raising the possibility of medicolegal consequences of failure to perform them.
- The procedures are time-critical and cannot await the arrival of an alternative specialist not already present. Simple pragmatism dictates that emergency physicians be trained to provide the necessary interventions.
The challenge of training
So how does one best train for these procedures? High volume trauma experience provided by a registrar term with the London Helicopter Emergency Medical Service or at a South African trauma centre will be an option for a very limited subset of trainees. Alternative training can be provided using simulation, animal labs, and cadaver labs, without risk to patients or requiring dedicated surgical specialty attachments.
Simulation manikins are not yet available for all the procedures mentioned, and lack realistic operable tissue. Human cadaver labs and live animal training bring administrative, legal, ethical and financial challenges that may be prohibitive to time and cash‐limited training schemes, or be less available to the ‘already trained’ providers in existing consultant posts. Even excellent focused cadaver-based courses such as the Royal College of Surgeons’ Definitive Surgical Trauma Skills course may not be appropriate for the emergency medicine environment: on such a course one of the authors (CR) was publicly castigated by a cardiothoracic surgeon instructor for inexpert suture technique during the resuscitative thoracotomy workshop, despite the former having successfully performed the procedure on several occasions ‘in the field’ without need of elaborate needlework.
An additional training challenge is that of metacompetence: the decision and ability to apply the competence at the right time. In the light of the relative technical simplicity of the practical procedures under discussion, this may indeed be the greatest challenge. Both authors can recount sad tales of colleagues failing to provide indicated life-saving interventions despite being technically capable of intervening. Reasons for reticence include ‘I haven’t been properly trained’, and ‘I wouldn’t feel supported if it went wrong’.
Where do we go from here?
We have presented clinical, ethical, practical, and medicolegal arguments in favour of emergency physicians providing these procedures. Collectively, the emergency medicine curricula of English-speaking nations mandate competence in them. The relative technical simplicity and overwhelming benefit:harm equation obviate the need to match the competence of a surgical subspecialist; these factors suggest training can be limited in time and cost as long as the metacompetences of ‘decision to act and knowing when to act’ are taught, simulated, and tested.
While we should capitalise on the technical expertise of surgical colleagues in the training situation, it is imperative that emergency physicians appreciative of the emergency department environment and equipment are directly involved in translating this training to emergency medicine practice. The rarity of the situations requiring these procedures requires that training should be revisited on a regular basis, preferably in the context of local departmental simulation in order to optimise equipment and teamwork preparation.
Finally, the College of Emergency Medicine needs to make it clear to its members and fellows that these procedures lie unquestionably within the domain of emergency medicine, and that emergency physicians are supported in performing them to the best of their abilities with limited training when circumstances dictate that this in the best interests of preserving a patient’s life, limb, or sight.
1. British Medical Association. Competency-based assessment discussion paper for consultants, May 2008. http://www.bma.org.uk/employmentandcontracts/doctors_performance/1_app raisal/CompetencyBasedAssessment.jsp Accessed 22nd March 2012
2. Davies GE, Lockey DJ. Thirteen Survivors of Prehospital Thoracotomy for Penetrating Trauma: A Prehospital Physician‐Performed Resuscitation Procedure That Can Yield Good Results. J Trauma. 2011;70(5):E75-8
3. Wise D, Davies G, Coats T, et al. Emergency thoracotomy: “how to do it”. Emerg Med J. 2005; 22(1):22–24 Free full text
4. Civil I. Emergency room thoracotomy: has availability triumphed over advisability in the care of trauma patients in Australasia? Emerg Med Australas. 2010;22(4):257‐9
5. Soar J, Perkins GD, Abbas G, et al. European Resuscitation Council Guidelines for Resuscitation 2010 Section 8. Cardiac arrest in special circumstances: Electrolyte abnormalities, poisoning, drowning, accidental hypothermia, hyperthermia, asthma, anaphylaxis, cardiac surgery, trauma, pregnancy, electrocution. Resuscitation. 2010;81(10):1400-33 Full text
6. Definitive Surgical Trauma Skills course. http://www.rcseng.ac.uk/courses/course-search/dsts.html Accessed 22nd March 2012
7. http://www.collemergencymed.ac.uk/Training-Exams/Curriculum/Curriculum%20from%20August%202010/ Accessed 22nd March 2012
8. http://www.eusem.org/cms/assets/1/pdf/european_curriculum_for_em-aug09-djw.pdf accessed 17 May 2012
9. The Model of the Clinical Practice of Emergency Medicine http://www.abem.org/PUBLIC/portal/alias__Rainbow/lang__en-%C2%AD%20US/tabID__4223/DesktopDefault.aspx Accessed 22nd March 2012
10. http://rcpsc.medical.org/residency/certification/objectives/emergmed_e.pdf Accessed 22nd March 2012
11. http://www.acem.org.au/media/publications/15_Fellowship_Curriculum.pdf accessed 17 May 2012
12. http://www.collegemedsa.ac.za/Documents/doc_173.pdf accessed 17 May 2012
Life, limb and sight-saving procedures-the challenge of competence in the face of rarity
Emerg Med J. 2012 Jul 16. [Epub ahead of print]
Comments Off on Hypotonic Versus Isotonic Fluids After Surgery for Children
Kids in hospital with injury, infection or other illness, and those undergoing the physiological stress of surgery, produce (appropriately) elevated antidiuretic hormone levels which contribute to the risk of hyponatraemia by impairing free water excretion in the kidney.
Deaths have occurred on general paediatric and surgery wards when fluid regimens containing low concentrations of sodium (classically 0.18% or 0.225% NaCl) have resulted in hyponatraemia in children without adequate electrolyte monitoring, leading some bodies to recommend at least 0.45% NaCl solutions for maintenance fluid therapy in children.
However two recent studies1,2 on postoperative children show an increased risk of hyponatraemia even with 0.45% saline, when compared with 0.9% saline or Hartmann’s solution (Hartmann’s is similar – almost identical – to Ringer’s lactate).
I like the fact that paediatricians used Hartmann’s in one of these studies1. I have worked with several paediatricians who never use Hartmann’s, either from lack of experience or because of concern about its lactate content (not appreciating the lactate is metabolised by the liver to bicarbonate).
This is ironic, since Alexis Hartmann (1898–1964) was a paediatrician.
Want more fluid therapy irony? The ‘balanced salt solution’ used by Brits and Australasians is Hartmann’s solution – named after an American. The one used by Americans is Lactated Ringer’s solution – named after the British physician Sydney Ringer (1834-1910).
Medical history enthusiasts can read more about Hartmann and Ringer here.
1. A randomised controlled trial of Hartmann’s solution versus half normal saline in postoperative paediatric spinal instrumentation and craniotomy patients.
Arch Dis Child. 2012 Jun;97(6):491-6
OBJECTIVE: To compare the difference in plasma sodium at 16-18 h following major surgery in children who were prescribed either Hartmann’s and 5% dextrose or 0.45% saline and 5% dextrose.
DESIGN: A prospective, randomised, open label study.
SETTING: The paediatric intensive care unit (650 admissions per annum) in a tertiary children’s hospital in Brisbane, Australia.
PATIENTS: The study group comprised 82 children undergoing spinal instrumentation, craniotomy for brain tumour resection, or cranial vault remodelling.
INTERVENTIONS: Patients received either Hartmann’s and 5% dextrose at full maintenance rate or 0.45% saline and 5% dextrose at two-thirds maintenance rate.
MAIN OUTCOMES MEASURES: Primary outcome measure: plasma sodium at 16-18 h postoperatively; secondary outcome measure: number of fluid boluses administered.
RESULTS: Mean postoperative plasma sodium levels of children receiving 0.45% saline and 5% dextrose were 1.4 mmol/l (95% CI 0.4 to 2.5) lower than those receiving Hartmann’s and 5% dextrose (p=0.008). In the 0.45% saline group, seven patients (18%) became hyponatraemic (Na <135 mmol/l) at 16-18 h postoperatively; in the Hartmann’s group no patient became hyponatraemic (p=0.01). No child in either fluid group became hypernatraemic.
CONCLUSIONS: The postoperative fall in plasma sodium was smaller in children who received Hartmann’s and 5% dextrose compared to those who received 0.45% saline and 5% dextrose. It is suggested that Hartmann’s and 5% dextrose should be administered at full maintenance rate postoperatively to children who have undergone major surgery in preference to hypotonic fluids.
2. Hypotonic versus isotonic maintenance fluids after surgery for children: a randomized controlled trial
Pediatrics. 2011 Nov;128(5):857-66.
OBJECTIVE: The objective of this randomized controlled trial was to evaluate the risk of hyponatremia following administration of a isotonic (0.9% saline) compared to a hypotonic (0.45% saline) parenteral maintenance solution (PMS) for 48 hours to postoperative pediatric patients.
METHODS: Surgical patients 6 months to 16 years of age with an expected postoperative stay of >24 hours were eligible. Patients with an uncorrected baseline plasma sodium level abnormality, hemodynamic instability, chronic diuretic use, previous enrollment, and those for whom either hypotonic PMS or isotonic PMS was considered contraindicated or necessary, were excluded. A fully blinded randomized controlled trial was performed. The primary outcome was acute hyponatremia. Secondary outcomes included severe hyponatremia, hypernatremia, adverse events attributable to acute plasma sodium level changes, and antidiuretic hormone levels.
RESULTS: A total of 258 patients were enrolled and assigned randomly to receive hypotonic PMS (N = 130) or isotonic PMS (N = 128). Baseline characteristics were similar for the 2 groups. Hypotonic PMS significantly increased the risk of hyponatremia, compared with isotonic PMS (40.8% vs 22.7%; relative risk: 1.82 [95% confidence interval: 1.21-2.74]; P = .004). Admission to the pediatric critical care unit was not an independent risk factor for the development of hyponatremia. Isotonic PMS did not increase the risk of hypernatremia (relative risk: 1.30 [95% confidence interval: 0.30-5.59]; P = .722). Antidiuretic hormone levels and adverse events were not significantly different between the groups.
CONCLUSION: Hypotonic Versus Isotonic Maintenance Fluids After Surgery for Children: A Randomized Controlled Trial.