Pre-hospital Echo

Pre-hospital physicians in Germany performed basic echo on patients with symptoms either of profound hypotension and/or severe dyspnoea/tachypnoea where judged by the physician to be in a ‘peri-resuscitation’ state, and on patients undergoing CPR. Features noted were; cardiac motion (present or absent), ventricular function (normal, moderately impaired, severely impaired, absent), right ventricular dilatation or pericardial collection.

A few interesting findings to note:

  • In almost all patients an interpretable view was achieved; in the CPR patients, the subcostal view was best
  • In PEA patients, there was a difference in survival to admission (to discharge isn’t documented) between those with and without sonographically evident cardiac wall motion (21/38 = 55% vs 1/13 = 8%)
  • In ‘suspected asystole’, some patients had sonographically evident cardiac wall motion, and 9/37 (24%) of these survived to hospital admission vs 4/37 (11%) with no wall motion. On this point, the authors note: ‘The ECG performance and interpretation were by experienced practitioners, and this therefore raises questions regarding the accuracy of an ECG diagnosis of asystole in the pre-hospital setting‘.

Purpose of the study: Focused ultrasound is increasingly used in the emergency setting, with an ALS- compliant focused echocardiography algorithm proposed as an adjunct in peri-resuscitation care (FEEL). The purpose of this study was to evaluate the feasibility of FEEL in pre-hospital resuscitation, the incidence of potentially treatable conditions detected, and the influence on patient management.

Patients, materials and methods: A prospective observational study in a pre-hospital emergency setting in patients actively undergoing cardio-pulmonary resuscitation or in a shock state. The FEEL protocol was applied by trained emergency doctors, following which a standardised report sheet was completed, including echo findings and any echo-directed change in management. These reports were then analysed independently.

Results: A total of 230 patients were included, with 204 undergoing a FEEL examination during ongoing cardiac arrest (100) and in a shock state (104). Images of diagnostic quality were obtained in 96%. In 35% of those with an ECG diagnosis of asystole, and 58% of those with PEA, coordinated cardiac motion was detected, and associated with increased survival. Echocardiographic findings altered management in 78% of cases.

Conclusions: Application of ALS-compliant echocardiography in pre-hospital care is feasible, and alters diagnosis and management in a significant number of patients. Further research into its effect on patient outcomes is warranted.

Focused echocardiographic evaluation in life support and peri-resuscitation of
emergency patients: A prospective trial

Resuscitation. 2010 Nov;81(11):1527-33

The Sichuan Straddle

I used to see it done on ‘ER’ but never knew people really straddled patients on stretchers doing CPR. Apparently they do in Sichuan, China and have now produced a manikin study to demonstrate its effectiveness. It might work there, but I imagine there are frequent situations in Australia (where I work) in which the combined weight of patient and paramedic would present an unfair load to the stretcher.

OBJECTIVE: To evaluate the efficacy of straddling external chest compression performed on moving stretchers.

METHODS: The study was a prospective, randomized, cross-over study on a manikin performed at a university hospital. Twenty subjects were selected from the 40 graduates using random numbers to participate in the study. Participants were randomized to either performing standard or straddling external chest compression followed by the other technique 7 days later. The compression variables and time to first compression were recorded.

RESULTS: Twenty subjects (12 males and 8 females) took part in the study. There were no differences between the standard and straddling external chest compression for the compression rate, effective compression percentage and compression depth. There was no difference between the standard external chest compression and straddling external chest compression for incorrect hand position and incomplete release compression. Time to first compression during straddling external chest compression (10.31 ± 1.65 s) was greater than that during standard external chest compression (2.74 ± 0.40 s) (P < 0.001).

CONCLUSIONS: The quality of straddling external chest compression performed on a moving stretcher was as effective as standard external chest compression performed on the floor. By performing straddling external chest compression, time for transporting victims to the emergency department to get advanced life support may be shortened.

The efficacy of straddling external chest compression on a moving stretcher
Resuscitation. 2010 Nov;81(11):1562

Bum crack fluid pump

Military guys are great at coming up with practical solutions. Need to infuse fluid in the field but have no pressure bag or drip stand? Putting the bag under the patient’s body can squeeze fluid in, but the best place under the patient wasn’t known. A volunteer military study infusing saline through a 14G cannula compared six under-body locations: heels, buttock cleft, sacrum, interscapular region, cervical spine and occiput.

The buttock cleft was best.

Using body weight as a pre-hospital fluid infusion device: the relationship between under-body position and flow rate.
J R Army Med Corps. 2008 Mar;154(1):31-3
Full text article

Laryngospasm and ketamine

What are the factors associated with laryngospasm in ketamine sedation? A large study was unable to identify specific predictors:

Objective: The objective of this study was to assess predictors of emergency department (ED) ketamine-associated laryngospasm using case-control techniques.

Methods: We performed a matched case-control analysis of a sample of 8282 ED ketamine sedations (including 22 occurrences of laryngospasm) assembled from 32 prior published series. We sequentially studied the association of each of 7 clinical variables with laryngospasm by assigning 4 controls to each case while matching for the remaining 6 variables. We then used univariate statistics and conditional logistic regression to analyze the matched sets.

Results: We found no statistical association of age, dose, oropharyngeal procedure, underlying physical illness, route, or coadministered anticholinergics with laryngospasm. Coadministered benzodiazepines showed a borderline association in the multivariate but not univariate analysis that was considered anomalous.

Conclusions: This case-control analysis of the largest available sample of ED ketamine-associated laryngospasm did not demonstrate evidence of association with age, dose, or other clinical factors. Such laryngospasm seems to be idiosyncratic, and accordingly, clinicians administering ketamine must be prepared for its rapid identification and management. Given no evidence that they decrease the risk of laryngospasm, coadministered anticholinergics seem unnecessary.

Laryngospasm During Emergency Department Ketamine Sedation: A Case-Control Study
Pediatr Emerg Care. 2010 Nov;26(11):798-802

What’s a normal newborn O2 sat?

Maybe they’re not just little adults after all: the normal reference ranges for oxygen saturation in the first few minutes of life have been defined for healthy newborns:

OBJECTIVE The goal was to define reference ranges for pulse oxygen saturation (SpO2) values in the first 10 minutes after birth for infants who received no medical intervention in the delivery room.

METHODS Infants were eligible if a member of the research team was available to record SpO2 immediately after birth. Infants were excluded if they received supplemental oxygen or any type of assisted ventilation. SpO2 was measured with a sensor applied to the right hand or wrist as soon as possible after birth; data were collected every 2 seconds.

RESULTS We studied 468 infants and recorded 61650 SpO2 data points. The infants had a mean ± SD gestational age of 38 ± 4 weeks and birth weight of 2970 ± 918 g. For all 468 infants, the 3rd, 10th, 50th, 90th, and 97th percentile values at 1 minute were 29%, 39%, 66%, 87%, and 92%, respectively, those at 2 minutes were 34%, 46%, 73%, 91%, and 95%, and those at 5 minutes were 59%, 73%, 89%, 97%, and 98%. It took a median of 7.9 minutes (interquartile range: 5.0–10 minutes) to reach a SpO2 value of >90%. SpO2 values for preterm infants increased more slowly than those for term infants. We present percentile charts for all infants, term infants of 37 weeks, preterm infants of 32 to 36 weeks, and extremely preterm infants of <32 weeks.

CONCLUSION These data represent reference ranges for SpO2 in the first 10 minutes after birth for preterm and term infants.

Defining the Reference Range for Oxygen Saturation for Infants After Birth
Pediatrics. 2010 Jun;125(6):e1340-7

US determined best LP position

Here ultrasound was used to ascertain the best position for doing a lumbar puncture in kids, where the interspinous space was maximised:

BACKGROUND Lumbar punctures are commonly performed in the pediatric emergency department. There is no standard, recommended, optimal position for children who are undergoing the procedure.

OBJECTIVE To determine a position for lumbar punctures where the interspinous space is maximized, as measured by bedside ultrasound.

METHODS A prospective convenience sample of children under age 12 was performed. Using a portable ultrasound device, the L3-L4 or L4-L5 interspinous space was measured with the subject in 5 different positions. The primary outcome was the interspinous distance between 2 adjacent vertebrae. The interspinous space was measured with the subject sitting with and without hip flexion. In the lateral recumbent position, the interspinous space wasmeasured with the hips in a neutral position as well as in flexion, both with and without neck flexion. Data were analyzed by comparing pairwise differences.

RESULTS There were 28 subjects enrolled (13 girls and 15 boys) at a median age of 5 years. The sitting-flexed position provided a significantly increased interspinous space (P < .05). Flexion of the hips increased the interspinous space in both the sitting and lateral recumbent positions (P < .05). Flexion of the neck, did not significantly change the interspinous space (P = .998).

CONCLUSIONS The interspinous space of the lumbar spine was maximally increased with children in the sitting position with flexed hips; therefore we recommend this position for lumbar punctures. In the lateral recumbent position, neck flexion does not increase the interspinous space and may increase morbidity; therefore, it is recommended to hold patients at the level of the shoulders as to avoid neckflexion.

Positioning for lumbar puncture in children evaluated by bedside ultrasound
Pediatrics. 2010 May;125(5):e1149-53

A more recent study also used ultrasound in infants to investigate the anatomic necessity and advantage derived from a tight flexed lateral recumbent position, since hypoxia has been observed in that position:

Objectives:  Hypoxia has been observed when infants undergo lumbar puncture in a tight flexed lateral recumbent position. This study used sonographic measurements of lumbar interspinous spaces to investigate the anatomic necessity and advantage derived from this tight flexed positioning in infants.

Methods:  This was a brief, prospective, observational study of a convenience sample of patients. Twenty-one healthy infants under 1 month of age were scanned in two positions: prone in a spine-neutral position and lateral recumbent with their knees bent into their chest and their neck flexed. In each position, a 5- to 10-MHz linear array transducer was used to scan midline along the lumbar spinous processes in the sagittal plane. The distances between the spinous processes were measured near the ligamentum flavum using the ultrasound machine’s calipers. Pulse oximetry was monitored on all infants during flexed positioning.

Results:  In the spine-neutral position, all studied interspinous spaces were much wider than a 22-gauge spinal needle (diameter 0.072 cm). The mean (±SD) interspinous spaces for L3-4, L4-5, and L5-S1 in a spine-neutral position were 0.42 (±0.07), 0.37 (±0.06), and 0.36 (±0.11) cm, respectively. Flexing the infants increased the mean lumbar interspinous spaces at L3-4, L4-5, and L5-S1 by 31, 51, and 44%, respectively.

Conclusions:  This study verified that tight, lateral flexed positioning substantially enhances the space between the lumbar spinous processes and that a spine-neutral position also allows for a large enough anatomic interspinous space to perform lumbar puncture. However, further clinical research is required to establish the feasibility of lumbar puncture in a spine-neutral position.

Evaluating infant positioning for lumbar puncture using sonographic measurements
Acad Emerg Med. 2011 Feb;18(2):215-8

Therapeutic hypothermia for newborns

More evidence that cooling the hypoxic neonatal brain improves outcomes….

OBJECTIVE Mild hypothermia after perinatal hypoxic-ischemic encephalopathy (HIE) reduces neurologic sequelae without significant adverse effects, but studies are needed to determine the most-efficacious methods.

METHODS In the trial, term neonates with clinical and electrophysiological evidence of HIE were assigned randomly to either a control group, with a rectal temperature of 37°C (range: 36.5–37.5°C), or a hypothermia group, cooled and maintained at a rectal temperature of 33.5°C (range: 33–34°C) with a cooling blanket for 72 hours, followed by slow rewarming. All infants received morphine (0.1 mg/kg) every 4 hours or an equivalent dose of fentanyl. Neurodevelopmental outcomes were assessed at the age of 18 to 21 months. The primary outcome was death or severe disability.

RESULTS A total of 129 newborn infants were enrolled, and 111 infants were evaluated at 18 to 21 months (53 in the hypothermia group and 58 in the normothermia group). The rates of death or severe disability were 51% in the hypothermia group and 83% in the normothermia group (P = .001; odds ratio: 0.21 [95% confidence interval [CI]: 0.09–0.54]; number needed to treat: 4 [95% CI: 3–9]). Hypothermia also had a statistically significant protective effect in the group with severe HIE (n = 77; P = .005; odds ratio: 0.17 [95% CI: 0.05–0.57]). Rates of adverse events during the intervention were similar in the 2 groups except for fewer clinical seizures in the hypothermia group.

CONCLUSION Systemic hypothermia in the trial showed a strong neuroprotective effect and was effective in the severe HIE group.

Systemic Hypothermia After Neonatal Encephalopathy: Outcomes of RCT
Pediatrics. 2010 Oct;126(4):e771-8

Update Dec 2014:

An RCT to determine if longer duration cooling (120 hours), deeper cooling (32.0°C), or both are superior to cooling at 33.5°C for 72 hours in neonates who are full-term with moderate or severe hypoxic ischemic encephalopathy.

Longer cooling, deeper cooling, or both compared with hypothermia at 33.5°C for 72 hours did not reduce NICU death. Small study.

Effect of depth and duration of cooling on deaths in the NICU among neonates with hypoxic ischemic encephalopathy: a randomized clinical trial
JAMA. 2014 Dec 24;312(24):2629-39

2J or 4J/kg in Paediatric Defibrillation?

Should we shock with 2J/kg or 4J/kg in Paediatric Defibrillation? The answer seems to be ‘we still don’t know’. Don’t worry – just follow the guidelines (reproduced for you at the bottom)

OBJECTIVE To examine the effectiveness of initial defibrillation attempts. We hypothesized that (1) an initial shock dose of 2 ± 10 J/kg would be less effective for terminating fibrillation than suggested in published historical data and (2) a 4 J/kg shock dose would be more effective.

PATIENTS AND METHODS This was a National Registry of Cardiopulmonary Resuscitation prospective, multisite, observational study of in-hospital pediatric (aged 18 years) ventricular fibrillation or pulseless ventricular tachycardia cardiac arrests from 2000–2008. Termination of ventricular fibrillation or pulseless ventricular tachycardia and event survival after initial shocks of 2 J/kg were compared with historic controls and a 4 J/kg shock dose.

RESULTS Of 266 children with 285 events, 173 of 285 (61%) survived the event and 61 of 266 (23%) survived to discharge. Termination of fibrillation after initial shock was achieved for 152 of 285 (53%) events. Termination of fibrillation with 2 ± 10 J/kg was much less frequent than that seen among historic control subjects (56% vs 91%; P < .001), but not different than 4 J/kg. Compared with 2 J/kg, an initial shock dose of 4 J/kg was associated with lower rates of return of spontaneous circulation (odds ratio: 0.41 [95% confidence interval: 0.21–0.81]) and event survival (odds ratio: 0.42 [95% confidence interval: 0.18–0.98]).

CONCLUSIONS The currently recommended 2 J/kg initial shock dose for in-hospital cardiac arrest was substantially less effective than previously published. A higher initial shock dose (4 J/kg) was not associated with superior termination of ventricular fibrillation or pulseless ventricular tachycardia or improved survival rates. The optimal pediatric defibrillation dose remains unknown.

Effect of defibrillation energy dose during in-hospital pediatric cardiac arrest
Pediatrics. 2011 Jan;127(1):e16-23

Here’s what the guidelines say:

Many AEDs have high specificity in recognizing pediatric shockable rhythms, and some are equipped to decrease (or attenuate) the delivered energy to make them suitable for infants and children <8 years of age. For infants a manual defibrillator is preferred when a shockable rhythm is identified by a trained healthcare provider (Class IIb, LOE C). The recommended first energy dose for defibrillation is 2 J/kg. If a second dose is required, it should be doubled to 4 J/kg. If a manual defibrillator is not available, an AED equipped with a pediatric attenuator is preferred for infants. An AED with a pediatric attenuator is also preferred for children <8 year of age. If neither is available, an AED without a dose attenuator may be used (Class IIb, LOE C). AEDs that deliver relatively high energy doses have been successfully used in infants with minimal myocardial damage and good neurological outcomes

Pediatric Basic Life Support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care
Full text document

Out of hospital monitoring in kids

I don’t have full text access to the Journal Pediatrics, so I’m not sure what I make of this small randomised trial comparing two types of blood pressure monitoring during paediatric transport:

BACKGROUND The “golden-hour” concept has led to emphasis on speed of patient delivery during pediatric interfacility transport. Timely intervention, in addition to enhanced monitoring during transport, is the key to improved outcomes in critically ill patients. Taking the ICU to the patient may be more beneficial than rapid delivery to a tertiary care center.

METHODS The Improved Monitoring During Pediatric Interfacility Transport trial was the first randomized controlled trial in the out-of-hospital pediatric transport environment. It was designed to determine the impact of improved blood pressure monitoring during pediatric interfacility transport and the effect on clinical outcomes in patients with systemic inflammatory response syndrome and moderate-to-severe head trauma. Patients in the control group had their blood pressure monitored intermittently with an oscillometric device; those in the intervention group had their blood pressure monitored every 12 to 15 cardiac contractions with a near-continuous, noninvasive device.

RESULTS Between May 2006 and June 2007, 1995, consecutive transport patients were screened, and 94 were enrolled (48 control, 46 intervention). Patients in the intervention group received more intravenous fluid (19.8 ± 22.2 vs 9.9 ± 9.9 mL/kg; P = .01), had a shorter hospital stay (6.8 ± 7.8 vs 10.9 ± 13.4 days; P = .04), and had less organ dysfunction (18 of 206 vs 32 of 202 PICU days; P = .03).

CONCLUSIONS Improved monitoring during pediatric transport has the potential to improve outcomes of critically ill children. Clinical trials, including randomized controlled trials, can be accomplished during pediatric transport. Future studies should evaluate optimal equipment, protocols, procedures, and interventions during pediatric transport, aimed at improving the clinical and functional outcomes of critically ill patients.

Enhanced Monitoring Improves Pediatric Transport Outcomes: A Randomized Controlled Trial
Pediatrics. 2011 Jan;127(1):42-8

Pre-hospital / HEMS podcast

I was lucky enough to be interviewed by the amazing Scott Weingart, an emergency medicine intensivist who runs the spectacular EMcrit podcast. We covered some stuff on pre-hospital airway management, physicians in pre-hospital care, and I had a rant about ‘scoop and run’ versus ‘stay and play’. Worryingly, Scott is keeping back some audio footage for a later podcast, probably containing an even bigger rant about things like ATLS.

Click the image to be taken to the EMcrit site where you can listen to the podcast.