All posts by Cliff

All Updates, PHARM, Resus, Trauma

Prehospital thoracostomy tube misplacement

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An interesting study from Germany examined prehospital thoracostomy tube (TT) placement by physicians working in the field. Of 69 patients who received them, 67 underwent prehospital intubation. 88 TT were placed in the 69 patients.
There were 19/88 (22%) radiologic chest tube misplacements (defined as too far in the chest, twisted, or bent). The position of 10/88 (11%) chest tubes had to be corrected. None of the patients with a TT had a “not-decompressed” pneumothorax or a chest tube placed below the diaphragm or into a solid organ.
Roughly half were placed in the ‘Monaldi’ position (the second or third intercostal space in the midclavicular line)…..

Monaldi position

 
 
 
 
 
 
 
 
 
…..and half in the Bülau position (fourth or fifth intercostal space in the midaxillary line).
Bülau position

 
 
 
 
 
 
 
 
 
There was no difference in the misplacement rates between the two positions although interestingly helicopter doctors (as opposed to ground response) more often opted for the Monaldi position.
It is not possible to tell from the results whether the TT insertion was indicated in all cases. Also, it would be interesting to know whether TT insertion preceded or followed tracheal intubation. While it is heartening that these physicians do not routinely rely on needle decompression, I cannot fathom while simple open thoracostomy was not used, avoiding the risk of tube misplacement and saving time.
See this post for a more thorough review of open thoracostomy and the limitations of needle decompression.


Objectives. To evaluate the frequency of use, placement site, success and misplacement rates, and need for intervention for tube thoracostomies (TTs), and the complications with endotracheal intubation associated with TT in the prehospital setting.

Methods. We performed a five-year, retrospective study using the records of 1,065 patients who were admitted to the trauma emergency room at a university hospital and who had received chest radiographs or computed tomography (CT) scans within 30 minutes after admission.

Results. Seven percent of all patients received a TT (5% unilateral, 2% bilateral). Ninety-seven percent of all patients with a TT were endotracheally intubated. The success rate for correctly placed chest tubes was 78%. Twenty-two percent of the chest tubes were misplaced (i.e., too far in the chest, twisted, or bent); half of those had to be corrected, with one needing to be replaced. There were no statistical differences in the frequency of Monaldi or Bülau positions, or the frequency of left or right chest TT. In addition, the two positions did not differ in misplacement rates or the need for intervention. Helicopter emergency medical services physicians used the Monaldi position significantly more frequently than the Bülau position. In-hospital physicians performing interhospital transfer used the Bülau position significantly more frequently, whereas ground emergency medical physicians had a more balanced relationship between the two positions. Tube thoracostomy had no influence on endotracheal tube misplacement rates, and vice versa.

Conclusion. Tube thoracostomy positioning mostly depends on the discretion of the physician on scene. The Monaldi and Bülau positions do not differ in misplacement or complication rates.

Incidence And Outcome Of Tube Thoracostomy Positioning In Trauma Patients
Prehosp Emerg Care. 2011 Oct 3. [Epub ahead of print]

Acute Med, All Updates, PHARM, Resus, Ultrasound

Prehospital echo predicts arrest outcome

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In hospital, the detection of cardiac standstill with ultrasound predicts a fatal outcome from cardiac arrest with a high degree of accuracy. A similar finding has been made in the prehospital setting. Interestingly, it was a better predictor than other commonly recognised factors associated with outcome: the presence of asystole, down time, bystander CPR, or end-tidal CO2 levels.


Introduction. The prognostic value of emergency echocardiography (EE) in the management of cardiac arrest patients has previously been studied in an in-hospital setting. These studies mainly included patients who underwent cardiopulmonary resuscitation (CPR) by emergency medicine technicians at the scene and who arrived at the emergency department (ED) still in a state of cardiac arrest. In most European countries, cardiac arrest patients are normally treated by physician-staffed emergency medical services (EMS) teams on scene. Transportation to the ED while undergoing CPR is uncommon. Objective. To evaluate the ability of EE to predict outcome in cardiac arrest patients when it is performed by ultrasound-inexperienced emergency physicians on scene.

Methods. We performed a prospective, observational study of nonconsecutive, nontrauma, adult cardiac arrest patients who were treated by physician-staffed urban EMS teams on scene. Participating emergency physicians (EPs) received a two-hour course in EE during CPR. After initial procedures were accomplished, EE was performed during a rhythm and pulse check. A single subxiphoid, four-chamber view was required for study enrollment. We defined sonographic evidence of cardiac kinetic activity as any detected motion of the myocardium, ranging from visible ventricular fibrillation to coordinated ventricular contractions. The CPR had to be continued for at least 15 minutes after the initial echocardiography. No clinical decisions were made based on the results of EE.

Results. Forty-two patients were enrolled in the study. The heart could be visualized successfully in all patients. Five (11.9%) patients survived to hospital admission. Of the 32 patients who had cardiac standstill on initial EE, only one (3.1%) survived to hospital admission, whereas four out of 10 (40%) patients with cardiac movement on initial EE survived to hospital admission (p = 0.008). Neither asystole on initial electrocardiogram nor peak capnography value, age, bystander CPR, or downtime was a significant predictor of survival. Only cardiac movement was associated with survival, and cardiac standstill at any time during CPR resulted in a positive predictive value of 97.1% for death at the scene.

Conclusion. Our results support the idea of focused echocardiography as an additional criterion in the evaluation of outcome in CPR patients and demonstrate its feasibility in the prehospital setting.

Cardiac Movement Identified on Prehospital Echocardiography Predicts Outcome
Prehosp Emerg Care. 2012 Jan 11. [Epub ahead of print]

All Updates, PHARM, Resus, Trauma

Training in prehospital and retrieval medicine

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I’ve been too busy to blog literature updates for a couple of weeks since I and my colleagues have been flat out running a two week training course in prehospital and retrieval medicine.
Our Helicopter Emergency Medical Service physicians and paramedics care for a wide range of adult and paediatric trauma and critical care patients in some challenging environments. We therefore need to provide a fairly comprehensive induction course for new recruits.
The new guys did us proud. They just need to stay this awesome.

Acute Med, All Updates, ICU, Resus

β-2 agonists could worsen ARDS outcome

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Image: Wikipedia. I really fancy a curry now.

A previous study (BALTI-1) suggested β-2 agonists may help in ARDS by reducing extravascular lung water. A randomised trial in the UK aimed to recruit 1334 patients to compare intravenous salbutamol infused for seven days with placebo (0.9% saline). However the Data Monitoring and Ethics Committee recommended that the study stop after the second interim analysis of 273 patients because of a significant increase in mortality. It is unclear why salbutamol is harmful, and could be due to lung, cardiovascular, or other metabolic effects, such as activation of the renin-angiotensin aldosterone system affecting fluid balance.


BACKGROUND:In a previous randomised controlled phase 2 trial, intravenous infusion of salbutamol for up to 7 days in patients with acute respiratory distress syndrome (ARDS) reduced extravascular lung water and plateau airway pressure. We assessed the effects of this intervention on mortality in patients with ARDS.

METHODS:We did a multicentre, placebo-controlled, parallel-group, randomised trial at 46 UK intensive-care units between December, 2006, and March, 2010. Intubated and mechanically ventilated patients (aged ≥16 years) within 72 h of ARDS onset were randomly assigned to receive either salbutamol (15 μg/kg ideal bodyweight per h) or placebo for up to 7 days. Randomisation was done by a central telephone or web-based randomisation service with minimisation by centre, pressure of arterial oxygen to fractional inspired oxygen concentration (PaO2/FiO2) ratio, and age. All participants, caregivers, and investigators were masked to group allocation. The primary outcome was death within 28 days of randomisation. Analysis was by intention-to-treat. This trial is registered, ISRCTN38366450 and EudraCT number 2006-002647-86.

FINDINGS:We randomly assigned 162 patients to the salbutamol group and 164 to the placebo group. One patient in each group withdrew consent. Recruitment was stopped after the second interim analysis because of safety concerns. Salbutamol increased 28-day mortality (55 [34%] of 161 patients died in the salbutamol group vs 38 (23%) of 163 in the placebo group; risk ratio [RR] 1·47, 95% CI 1·03-2·08).

INTERPRETATION:Treatment with intravenous salbutamol early in the course of ARDS was poorly tolerated. Treatment is unlikely to be beneficial, and could worsen outcomes. Routine use of β-2 agonist treatment in ventilated patients with this disorder cannot be recommended.

FUNDING:UK Medical Research Council, UK Department of Health, UK Intensive Care Foundation.

Effect of intravenous β-2 agonist treatment on clinical outcomes in acute respiratory distress syndrome (BALTI-2): a multicentre, randomised controlled trial
Lancet 379(9812, 21–27 January 2012, Pages 229–235

All Updates, ICU, PHARM, Resus, Trauma

FIRST: Fluids in Resuscitation of Severe Trauma

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This is the first randomized, controlled, double-blind study comparing crystalloids with isotonic colloids in trauma. 0.9% saline was compared with hydroxyethyl starch, HES 130/0.4, as a resuscitation fluid in pre-defined subgroups of penetrating and blunt trauma. While a primary outcome measure of gastrointestinal recovery might not seem an obvious choice to some of us, previous research has indicated this to be an issue with crystalloid and the authors clearly defined this as a predefined outcome when registering the trial here.

I don't have any pictures of colloids. Here's where I work.

Colloids tend to require smaller volumes than crystalloid to achieve the same degree of plasma expansion. An interesting finding in this study is that the volume of saline administered was 1.5 times that of hydroxyethyl starch – a very similar ratio to that seen in the SAFE study which compared saline with 4% albumin in intensive care patients.
The authors assert: “..the better lactate clearance in the P-HES group indicated superior tissue resuscitation with the colloid.” There are a number of reasons why this might be a bit of stretch, including the use of epinephrine in some patients which is known to be a cause of hyperlactataemia.
This is a small study whose conclusions should be treated with caution, but which provides an important contribution to the pool of fluid resuscitation literature. If you have full text access to the British Journal of Anaesthesia, the letters pages provide excellent critiques and responses regarding potential flaws in this paper. Nevertheless, it’s one to know about – I’m sure the FIRST trial is going to be quoted for some time to come, including, I suspect, by the manufacturers of certain colloids.


Background The role of fluids in trauma resuscitation is controversial. We compared resuscitation with 0.9% saline vs hydroxyethyl starch, HES 130/0.4, in severe trauma with respect to resuscitation, fluid volume, gastrointestinal recovery, renal function, and blood product requirements.

Methods Randomized, controlled, double-blind study of severely injured patients requiring>3 litres of fluid resuscitation. Blunt and penetrating trauma were randomized separately. Patients were followed up for 30 days.

Results A total of 115 patients were randomized; of which, 109 were studied. For patients with penetrating trauma (n=67), the mean (sd) fluid requirements were 5.1 (2.7) litres in the HES group and 7.4 (4.3) litres in the saline group (P<0.001). In blunt trauma (n=42), there was no difference in study fluid requirements, but the HES group required significantly more blood products [packed red blood cell volumes 2943 (1628) vs 1473 (1071) ml, P=0.005] and was more severely injured than the saline group (median injury severity score 29.5 vs 18; P=0.01). Haemodynamic data were similar, but, in the penetrating group, plasma lactate concentrations were lower over the first 4 h (P=0.029) and on day 1 with HES than with saline [2.1 (1.4) vs 3.2 (2.2) mmol litre−1; P=0.017]. There was no difference between any groups in time to recovery of bowel function or mortality. In penetrating trauma, renal injury occurred more frequently in the saline group than the HES group (16% vs 0%; P=0.018). In penetrating trauma, maximum sequential organ function scores were lower with HES than with saline (median 2.4 vs 4.5, P=0.012). No differences were seen in safety measures in the blunt trauma patients.
Conclusions In penetrating trauma, HES provided significantly better lactate clearance and less renal injury than saline. No firm conclusions could be drawn for blunt trauma.

Resuscitation with hydroxyethyl starch improves renal function and lactate clearance in penetrating trauma in a randomized controlled study: the FIRST trial (Fluids in Resuscitation of Severe Trauma)

Br J Anaesth. 2011 Nov;107(5):693-702

All Updates, ICU, Resus

Adjacent haemofiltration catheters can remove CVC drugs

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An important consideration when siting your lines in your critical care patients who require renal replacement therapy…


Dual-lumen haemodiafiltration catheters enable continuous renal replacement therapy in the critically ill and are often co-located with central venous catheters used to infuse drugs. The extent to which infusions are immediately aspirated by an adjacent haemodiafiltration catheter remains unknown. A bench model was constructed to evaluate this effect. A central venous catheter and a haemodiafiltration catheter were inserted into a simulated central vein and flow generated using centrifugal pumps within the simulated vein and haemodiafiltration circuit. Ink was used as a visual tracer and creatinine solution as a quantifiable tracer. Tracers were completely aspirated by the haemodiafiltration catheter unless the infusion was at least 1 cm downstream to the arterial port. No tracer was aspirated from catheters infusing at least 2 cm downstream. Orientation of side ports did not affect tracer elimination. Co-location of central venous and haemodiafiltration catheters may lead to complete aspiration of infusions into the haemodiafilter with resultant drug under-dosing.

Adjacent central venous catheters can result in immediate aspiration of infused drugs during renal replacement therapy
Anaesthesia. 2012 Feb;67(2):115-121

All Updates, Guidelines, Kids, Resus

Caution with intraosseous adenosine

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Two cases of failed cardioversion of SVT after tibial intraosseous administration of adenosine in infants are described in this month’s Pediatric Emergency Care. Both cases were subsequently cardioverted by intravenous adenosine. The maximum intraosseous dose given was 0.25 mg/kg. The successful IV doses were not higher than the IO doses.
It has been noted before that infants may require relatively higher doses of adenosine than children and that 0.2 mg/kg might even be considered a starting dose in infancy. I wonder if a bigger IO dose would have been effective, or whether a proximal humeral insertion site would make a difference. IO adenosine has been successfully used in infants and piglets.
This interesting case series provides a helpful caution in the management of paediatric SVT.

ABSTRACT: Supraventricular tachycardia (SVT) is a common tachyarrhythmia in the pediatric population that can necessitate immediate treatment. Adenosine has been well studied as a mainstay treatment, but the methods of adenosine administration have not been very well delineated. The intraosseous technique has presented itself as a possible method of administration. We describe 2 cases in which adenosine was administered through bone marrow infusion to convert SVT without success. The cases we describe show that intraosseous is not a reliable method of administering adenosine to stop SVT. Both patients presented with SVT refractory to vagal maneuvers and difficult intravenous placement. Intraosseous access was achieved, but administration of adenosine at increasing doses was unable to successfully convert the arrhythmia.

Intraosseous Infusion Is Unreliable for Adenosine Delivery in the Treatment of Supraventricular Tachycardia
Pediatr Emerg Care. 2012 Jan;28(1):47-8

Acute Med, All Updates, ICU, Resus

Vasopressin – what it does and doesn't do

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The current Surviving Sepsis campaign guidelines recommend that vasopressin should not be administered as the initial vasopressor in septic shock, and that vasopressin at constant dosage of 0.03 units/min may be added to norepinephrine with anticipation of an effect equivalent to that of norepinephrine alone. European intensivists conducted a systematic review to determine vasopressin’s risks and benefits in vasodilatory shock. There was no demonstrated survival benefit but its use is associated with a significant reduction in norepinephrine requirement.
Interestingly, the authors point out: ‘Low-dose vasopressin may help to restore blood pressure in patients with hypotension refractory to catecholamines, and may favor pulmonary vasodilation and increase glomerular filtration rate and plasma cortisol levels’.
My take home: consider its use if an apparent vasodilatory shock state is refractory to catecholamines, but don’t stress if you don’t have access to it (or it will complicate practical aspects of organising resuscitation and transfer), since there’s still no clear evidence for outcome benefit.


OBJECTIVE:
To examine the benefits and risks of vasopressin or its analog terlipressin for patients with vasodilatory shock.

DATA SOURCE:
We searched the CENTRAL, MEDLINE, EMBASE, and LILACS databases (up to March 2011) as well as reference lists of articles and proceedings of major meetings; we also contacted trial authors. We considered randomized and quasirandomized trials of vasopressin or terlipressin versus placebo or supportive treatment in adult and pediatric patients with vasodilatory shock. The primary outcome for this review was short-term all-cause mortality.

STUDY SELECTION:
We identified 10 randomized trials (1,134 patients). Six studies were considered for the main analysis on mortality in adults.

DATA EXTRACTION AND SYNTHESIS:
The crude short-term mortality was 206 of 512 (40.2%) in vasopressin/terlipressin-treated patients and 198 of 461 (42.9%) in controls [six trials, risk ratio (RR) = 0.91; 95% confidence interval (CI) 0.79-1.05; P = 0.21; I (2) = 0%]. There were 49 of 463 (10.6%) patients with serious adverse events in the vasopressin/terlipressin arm and 51 of 431 (11.8%) in the control arm (four trials, RR = 0.90; 95% CI 0.49-1.67; P = 0.75; I (2) = 26%). Metaregression analysis showed negative correlation between vasopressin dose and norepinephrine dose (P = 0.03).

CONCLUSIONS:
Overall, use of vasopressin or terlipressin did not produce any survival benefit in the short term in patients with vasodilatory shock. Physicians may value the sparing effects of vasopressin/terlipressin on norepinephrine requirement given its apparent safe profile.

Vasopressin for treatment of vasodilatory shock: an ESICM systematic review and meta-analysis
Intensive Care Med. 2012 Jan;38(1):9-19

All Updates, ICU, Kids, PHARM, Resus

A big brain saves a little one

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Something I’ve been teaching for years – but never actually done – has been described in a case report from Oman.
A 2 year old child suffered a respiratory arrest due to an inhaled foreign body, which led to a bradyasystolic cardiac arrest. She was intubated by the resuscitation team who could not achieve any ventilation through the tube. The tube was removed and reinserted by an ‘expert’ (there is no mention of capnometry, for what it’s worth) and the same problem persisted.
The life-saving manouevre was to insert the tracheal tube further down into the right main bronchus and then withdraw to the trachea. This forced the obstructing object distally so that one-lung ventilation was then possible, resulting in return of spontaneous circulation and oxygen saturations in the mid-80’s. The object – a broken piece of plastic – was removed bronchoscopically and happily the child made an uneventful recovery.
Is this technique in your list of life-saving tricks? Hopefully, it is now.
A child is alive because a doctor was able to ‘think outside the guidelines’ in an incredibly high pressure situation. Rigid adherence to ACLS procedures here would have been futile. The guidelines save lives, but a few more can be saved when care can be individualised to the clinical situation by a thinking clinician.
Well done Dr Mishra and colleagues.

Sudden near-fatal tracheal aspiration of an undiagnosed nasal foreign body in a small child
Emerg Med Australas. 2011 Dec;23(6):776-8
[And here’s something else to consider if you have no airway equipment with you and your basic choking algorithm isn’t working]

All Updates, Resus, Trauma

Prehospital fluids for head injury – keep it simple

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Just in case you thought you might be missing some recent gem on what we should be giving patients with traumatic brain injury in the field: a team from Melbourne has reviewed the literature and concluded isotonic crystalloids (Ringer’s or Saline) are as good as anything else.


The early management of patients who have sustained traumatic brain injury is aimed at preventing secondary brain injury through avoidance of cerebral hypoxia and hypoperfusion. Especially in hypotensive patients, it has been postulated that hypertonic crystalloids and colloids might support mean arterial pressure more effectively by expanding intravascular volume without causing problematic cerebral oedema. We conducted a systematic review to investigate if hypertonic saline or colloids result in better outcomes than isotonic crystalloid solutions, as well as to determine the safety of minimal volume resuscitation, or delayed versus immediate fluid resuscitation during prehospital care for patients with traumatic brain injury. We identified nine randomized controlled trials and one cohort study examined the effects of hypertonic solutions (with or without colloid added) for prehospital fluid resuscitation. None has reported better survival and functional outcomes over the use of isotonic crystalloids. The only trial of restrictive resuscitation strategies was underpowered to demonstrate its safety compared with aggressive early fluid resuscitation in head injured patients, and maintenance of cerebral perfusion remains the top priority.

Review article: Prehospital fluid management in traumatic brain injury
Emerg Med Australas. 2011 Dec;23(6):665-76