Category Archives: PHARM

Prehospital and Retrieval Medicine

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

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.

Helicopters between hospitals

More National Trauma Databank analysis coming out in favour of helicopter transport: this time looking at interhospital transfer:

Background: Helicopter transport (HT) is frequently used for interfacility transfer of injured patients to a trauma center. The benefits of HT over ground transport (GT) in this setting are unclear. By using a national sample, the objective of this study was to assess whether HT impacted outcomes following interfacility transfer of trauma patients.

Methods: Patients transferred by HT or GT in 2007 were identified using the National Trauma Databank (version 8). Injury severity, resource utilization, and survival to discharge were compared. Stepwise logistic regression was used to determine whether transport modality was a predictor of survival after adjusting for covariates. Regression analysis was repeated in subgroups with Injury Severity Score (ISS) ≤15 and ISS >15.
Results: There were 74,779 patients transported by helicopter (20%) or ground (80%). Mean ISS was higher in patients transported by helicopter (17 ± 11 vs. 12 ± 9; p < 0.01) as was the proportion with ISS >15 (49% vs. 28%; odds ratio [OR], 2.53; 95% confidence interval [CI], 2.43-2.63). Patients transported by helicopter had higher rates of intensive care unit admission (54% vs. 29%; OR, 2.86; 95% CI, 2.75-2.96), had shorter transport time (61 ± 55 minutes vs. 98 ± 71 minutes; p < 0.01), and had shorter overall prehospital time (135 ± 86 minutes vs. 202 ± 132 minutes; p < 0.01). HT was not a predictor of survival overall or in patients with ISS ≤15. In patients with ISS >15, HT was a predictor of survival (OR, 1.09; 95% CI, 1.02-1.17; p = 0.01).
Conclusions: Patients transported by helicopter were more severely injured and required more hospital resources than patients transported by ground. HT offered shorter transport and overall prehospital times. For patients with ISS >15, HT was a predictor of survival. These findings should be considered when developing interfacility transfer policies for patients with severe injuries.
Helicopters Improve Survival in Seriously Injured Patients Requiring Interfacility Transfer for Definitive Care
J Trauma. 2011 Feb;70(2):310-4.

Neck movement in spite of collar

A cadaveric study using an artificially created unstable cervical spine injury has shown marked displacement of the vertebrae when cervical collars were applied, and when the bodies were moved in a way that simulated normal transfer and log-rolling. There was no comparison with a no-collar situation, so we can’t say from this that collars are necessarily bad, just that they’re no good in this cadaveric model. I like this statement by the authors:
A variety of collars, backboards, and other equipment and techniques are being used in an attempt to achieve spine stabilization, largely without any validation of efficacy when used in the presence of a severe cervical injury. Randomized, prospective clinical trial designs are challenging in this domain theless, basic cadaver studies can provide valuable insight into potential clinical efficacy.

"Severe unstable injuries were created in seven fresh whole human cadavers"

Even more musical to my ears is the editorial commentary by neurosurgery professor Richard L. Saunders, MD:
…the more compelling question is whether there is a place for collars in emergent protection of the injured cervical spine or are they simply a gimcrack***?
The incidence of second injuries to the spinal cord in the extraction of accident victims under the best of EMT performance is not known and would be difficult to determine. However, in an effort to minimize that incidence, paramedical gospel is the application of a cervical collar, maintaining the neck in in-line and in a neutral position. By definition, this gospel implies the deliberate movement of the neck to apply an orthotic known to be nonprotective. Furthermore, the neutral and in-line admonition implies that the patient’s neck position can be safely adjusted to “look better” without a shred of evidence that this might be a safer strategy than avoiding any unnecessary neck movement whatsoever….
…In a conclusion common to many small study reports, the authors recommend that more work should be done in this area. In my opinion that might be best in refinements of extraction methods with an eye to only that neck movement necessary to resuscitation, collar be damned.

Motion Within the Unstable Cervical Spine During Patient Maneuvering: The Neck Pivot-Shift Phenomenon
J Trauma. 2011 Jan;70(1):247-50
*** I confess never to have encountered this word before. According to the freedictionary.com, a gimcrack is ‘A cheap and showy object of little or no use; a gewgaw‘. Now, WTF is a gewgaw?!?!

CPR on your own? Stay at the head end

In this manikin study, single-rescuer bag-mask ventilation (BMV) with chest compressions was tried in three different positions. Staying at the head end to deliver effective BMV, with ‘over-the-head’ chest compressions from that position, was best.

Background The 2005 guidelines for cardiopulmonary resuscitation (CPR) do not include a statement on performance of basic life support by a single healthcare professional using a bagevalveemask device. Three positions are possible: chest compressions and ventilations from over the head of the casualty (over-the-head CPR), from the side of the casualty (lateral CPR), and chest compressions from the side and ventilations from over the head of the casualty (alternating CPR). The aim of this study was to compare CPR quality of these three positions.
Methods 102 healthcare professionals were randomised to a crossover design and performed a 2-min CPR test on a manikin for each position.
Results The hands-off time over a 2-min interval was not significantly different between over-the-head (median 31 s) and lateral (31 s) CPR, but these compared favourably with alternating CPR (36 s). Over-the-head CPR resulted in significantly more chest compressions (155) compared with lateral (152) and alternating CPR (149); the number of correct chest compressions did not differ significantly (119 vs 122 vs 109). Alternating CPR resulted in significantly less inflations (eight) compared with over-the-head (ten) and lateral CPR (ten). Lateral CPR led to significantly less correct inflations (three) compared with over-the-head (five) and alternating CPR (four).
Conclusions In the case of a single healthcare professional using a bagevalveemask device, the quality of over-the-head CPR is at least equivalent to lateral, and superior to alternating CPR. Because of the potential difficulties in bagevalveemask ventilation in the lateral position, the authors recommend over-the-head CPR.
Comparison of the over-the-head, lateral and alternating positions during cardiopulmonary resuscitation performed by a single rescuer with a bag valve mask device
Emerg Med J. 2010 Oct 14. [Epub ahead of print]

Estimating child weight in Hong Kong

We know that the ‘APLS formula’ is inaccurate as a tool for estimating weight in Western children, and British and Australian researchers have devised more fitting formulae for their local populations as described here.

Summary table from the Hong Kong study of existing weight estimation rules

The emergency medicine team at the Accident and Emergency Medicine Academic Unit, Chinese University of Hong Kong have now provided a solution for Chinese children:

weight (kg) = (3 x age) + 5.

This was most accurate and precise in children <7 years old.
Age-based formulae to estimate children’s weight in the emergency department
Emerg Med J. 2010 Oct 13. [Epub ahead of print]

It gets tricky if they're 50% Chinese. Luckily, he's my son and I know how much he weighs.

GCS in intubated patients

We use the Glasgow Coma Score to describe conscious level, derived from eye opening, verbal response, and motor response.
One problem is that if your patient is intubated, there can’t be a verbal response. There are some ways round this. Imagine your intubated patient opens eys to a painful stimulus and withdraws his limb from one:

  • Just give him the lowest score (1) for the verbal component – E2M4V1
  • Write ‘V’ (ventilated) or ‘T’ (tube), eg. E2M4VT
  • Make it up, based on what you would expect the V score to be based on the E and M scores.

Weird as it sounds, there is a model for this, demonstrated in the paper abstracted below. The Derived Verbal Score = -0.3756 + Motor Score * (0.5713) + Eye Score * (0.4233).

Don’t worry…if you really want to use this, you don’t have to memorise that equation; there is an online calculator for it here and if you try it you’ll see this patient gets a derived verbal score of 2.3, and therefore a GCS of 7.3! Your decision now whether to round up or down. (In the meantime, I’ve given the patient a V of 1 and called it GCS E2M4VT=7.)
Alternatively, of course, you could try a better validated score that gives more information, the FOUR score, as validated here. The problem is, most people won’t know what you’re talking about.
The conundrum of the Glasgow Coma Scale in intubated patients: a linear regression prediction of the Glasgow verbal score from the Glasgow eye and motor scores.
Meredith W, Rutledge R, Fakhry SM, Emery S, Kromhout-Schiro S.
BACKGROUND: The Glasgow Coma Scale (GCS), which is the foundation of the Trauma Score, Trauma and Injury Severity Score, and the Acute Physiology and Chronic Health Evaluation scoring systems, requires a verbal response. In some series, up to 50% of injured patients must be excluded from analysis because of lack of a verbal component for the GCS. The present study extends previous work evaluating derivation of the verbal score from the eye and motor components of the GCS.
METHODS: Data were obtained from a state trauma registry for 24,565 unintubated patients. The eye and motor scores were used in a previously published regression model to predict the verbal score: Derived Verbal Score = -0.3756 + Motor Score * (0.5713) + Eye Score * (0.4233). The correlation of the actual and derived verbal and GCS scales were assessed. In addition the ability of the actual and derived GCS to predict patient survival in a logistic regression model were analyzed using the PC SAS system for statistical analysis. The predictive power of the actual and the predicted GCS were compared using the area under the receiver operator characteristic curve and Hosmer-Lemeshow goodness-of-fit testing.
RESULTS: A total of 24,085 patients were available for analysis. The mean actual verbal score was 4.4 +/- 1.3 versus a predicted verbal score of 4.3 +/- 1.2 (r = 0.90, p = 0.0001). The actual GCS was 13.6 + 3.5 versus a predicted GCS of 13.7 +/- 3.4 (r = 0.97, p = 0.0001). The results of the comparison of the prediction of survival in patients based on the actual GCS and the derived GCS show that the mean actual GCS was 13.5 + 3.5 versus 13.7 + 3.4 in the regression predicted model. The area under the receiver operator characteristic curve for predicting survival of the two values was similar at 0.868 for the actual GCS compared with 0.850 for the predicted GCS.
CONCLUSIONS: The previously derived method of calculating the verbal score from the eye and motor scores is an excellent predictor of the actual verbal score. Furthermore, the derived GCS performed better than the actual GCS by several measures. The present study confirms previous work that a very accurate GCS can be derived in the absence of the verbal component.
The conundrum of the Glasgow Coma Scale in intubated patients: a linear regression prediction of the Glasgow verbal score from the Glasgow eye and motor scores.
J Trauma. 1998 May;44(5):839-44 (if you have full text access to Journal of Trauma the best bit about this article is the discussion on pages 844-5 in which surgeons wrestle with the meaning of the word ‘conundrum’ and the spelling of ‘Glasgow’).