Cardiac Drugs at High Temps; Selective Immobilization; ETI Survival Benefit

Drug Degradation at High Temperatures

Gill MA, Kislik AZ, Gore L, Chandna A. Stability of advanced life support drugs in the field. Am J Health Syst Pharm 61(6):597–602, March 2004.

Abstract: The effects of wide temperature variations on the stability of atropine, epinephrine and lidocaine stored under field conditions in advanced life support (ALS) paramedic units were evaluated. Methods—Vehicles from various ALS paramedic units were selected throughout Los Angeles County, CA, including desert, marine and helicopter-based divisions. A temperature-recording device was placed in the compartment where drugs are stored and used to record and store temperature data at 15-minute intervals. Three autoinjector-style syringes of atropine, epinephrine and lidocaine were taken from stock for each ALS unit and placed in each vehicle, while three control syringes were stored in the laboratory under controlled conditions. Six samples of each drug were withdrawn at time 0 and on days 5, 10, 15, 30 and 45. Samples were analyzed using high-performance liquid chromatography. Stock solutions, created using analytical-grade atropine, epinephrine and lidocaine, were used to construct five-point standard curves to determine the drug concentration of each sample. Results—Seven sites exceeded 104ºF (40ºC) for as little as 30 minutes and as long as 795 minutes. Ten of the sites achieved a mean kinetic temperature (MKT) above 77ºF (25ºC), with the highest MKT calculated at 84.1ºF (28.9ºC) over a 45-day period. There was no evidence of drug degradation at any site, at any temperature or at any time point. Conclusion—Atropine, epinephrine and lidocaine can be stored at temperatures of up to 84.1ºF (28.9ºC) for up to 45 days and tolerate temperature spikes of up to 125ºF (51.7ºC) for a cumulative time of 795 minutes (13.25 hours) without undergoing degradation.

Comment: Medications stored in ambulances are subjected to much greater temperature extremes than in other healthcare settings such as offices and hospitals. Many have speculated that this may lead to early degradation and diminution or loss of clinical effect. This study nicely demonstrates that the common cardiac resuscitation drugs—atropine, epinephrine and lidocaine—can withstand peak temperatures of up to 125ºF and a total warm-climate time of 45 days. However, this does not necessarily apply to other drugs, longer time periods or even higher temperatures (infrequent as those might be). EMS systems, especially those that are lower-volume and/or in hotter climates, should still be cautious about swapping out their supplies.

Selective C-Spine Immobilization by EMT-Bs

Dunn TM, Dalton A, Dorfman T, Dunn WW. Are emergency medical technician-basics able to use a selective immobilization of the cervical spine protocol? A preliminary report. Preh Emerg Care 8(2):207–11, Apr–June 2004.

Abstract: The objective was to initiate a first step in determining whether EMT-Basics are capable of using a protocol that allows for selective immobilization of the cervical spine. Such protocols are coming into use at an advanced life support level and could be beneficial when used by basic life support providers. Methods—A convenience sample of participants (n=95) from 11 emergency medical services agencies and one college class participated in the study. All participants evaluated six patients in written scenarios and decided which should be placed into spinal precautions according to a selective spinal immobilization protocol. Systems without an existing selective spinal immobilization protocol received a one-hour continuing-education lecture regarding the topic. College students received a similar lecture written so laypersons could understand the protocol. Results—All participants showed proficiency when applying a selective immobilization protocol to patients in paper-based scenarios. Furthermore, EMT-Basics performed at the same level as paramedics when following the protocol. Statistical analysis revealed no significant differences between EMT-Basics and paramedics. A follow-up group of college students (added to have a non-EMS comparison group) also performed as well as paramedics when making decisions to use spinal precautions. Differences between college students and paramedics were also statistically insignificant. Conclusions—The results suggest that EMT-Basics are as accurate as paramedics when making decisions regarding selective immobilization of the cervical spine during paper-based scenarios. That laypersons are also proficient when using the protocol could indicate that it is extremely simple to follow. This study is a first step toward the necessary additional studies evaluating the efficacy of EMT-Basics using selective immobilization as a regular practice.

Comment: Traditional EMS teaching has held that everyone with a head injury, involved in a motor vehicle crash, or with other significant (or sometimes insignificant) head or neck trauma (or even just the potential for such trauma) should be placed on a backboard and have their entire spine immobilized. Unfortunately, this often commits the patient to unnecessary hours on a hard board, significant pain, and short- and long-term neurological symptoms. Recent studies have concluded that a significant spinal injury can often be ruled out with a careful history and physical exam. This study helps us better understand what level of training is needed to perform this evaluation. If EMT-Bs can accurately evaluate and “clinically clear” patients, it will avoid unnecessary treatment. More field research is needed, but at this point this looks promising.

Survival Benefit of Prehospital ETI

Stockinger ZT, McSwain NE, Jr. Prehospital endotracheal intubation for trauma does not improve survival over bag-valve mask ventilation. J Trauma 56(3):531–6, March 2004.

Abstract: Few data exist supporting a survival benefit to prehospital endotracheal intubation (ETI) over bag-valve mask ventilation (BVM) in trauma patients. Methods—Data were reviewed from all trauma patients transported to [authors’] Level I trauma center receiving prehospital ETI or BVM. Mortality was adjusted by age, Revised Trauma Score, Injury Severity Score and mechanism of injury (penetrating vs. blunt). Results—Of 5,773 patients, 316 (5.5%) had ETI and 217 (3.8%) had BVM. Patients receiving ETI were significantly more likely to die (88.9% vs. 30.9%, p < 0.0001). When corrected for Injury Severity Score, Revised Trauma Score and mechanism of injury, ETI was associated with similar or greater mortality than BVM. ETI patients had longer prehospital times (22.0 vs. 20.1 minutes, p=0.0241). Conclusion—In [authors’] trauma system, when corrected for mechanism and severity of anatomic and physiologic injury, ETI confers no survival advantage over BVM and slightly increases prehospital time.

Comment: The role of prehospital endotracheal intubation continues to be controversial. ETI was included in the original paramedic scopes of practice because 1) it was used in the hospital, and 2) paramedics could be trained to perform the skill—not because a clinical study concluded that out-of-hospital patients benefited from it. Since then, there have been numerous reports such as this (retrospective reviews)—some that suggest ETI may help, some that it may harm, and others that show no difference. Unfortunately, because ETI has become such a well-recognized paramedic skill, it will be difficult to perform the much-needed definitive studies: prospective randomized trials. This study is more evidence, though, that for the trauma patient, rapid assessment, BVM ventilation and expeditious transportation should be emphasized over prolonged attempts at ETI.