A literature review of the prehospital use of neuromuscular blocking agents by air medical personnel to facilitate endotracheal intubation

Air medical personnel in the United States have used neuromuscular blocking agents to facilitate endotracheal intubation in the field for more than a decade. This literature review examines 15 studies to investigate their experience and explores the following specific areas: the intubation success rate in patients who did or did not receive these agents, the intubation success rate of air medical personnel before and after they incorporated these agents into their practice, the neuromuscular blocking agents and adjunct medications used by air medical personnel, and the disposition of patients who could not be intubated after an agent was given. The data suggest that, overall, air medical personnel use these agents safely and effectively. Suggestions are offered for future studies, including examining ground time when agents are used to facilitate intubation, complications of their use in this setting, and the use of simulators to train personnel in the administration of these medications.

Medication calculation skills of practicing paramedics

OBJECTIVE

To assess the medication calculation skills among a group of practicing paramedics, the types of computations they find most difficult, and the relationship between drug calculation skills and various demographic characteristics.

METHODS

A demographic survey and a ten-item drug calculation examination were administered to a convenience sample of 109 practicing paramedics representing a cross-section of emergency medical services (EMS) system characteristics in North Carolina. Examinations were scored independently by two graders and error types were assigned to incorrect responses. Examination results were then correlated with demographic and EMS system characteristics.

RESULTS

Overall performance on the drug calculation examination was poor. The mean score was 51.4% (SD 27.4). Intravenous flow rate problems and medication bolus problems were calculated correctly in 68.8% of the cases, followed by non-weight-based medication infusions (33.9%), weight-based medication infusions (32.5%), and percentage-based medication infusions (4.5%). Examination scores were higher among paramedics with college level education, but scores were lower among paramedics with more years of EMS experience. Conceptual errors (i.e., errors in setting up the problem) were more prevalent than mathematical errors, errors in weight conversion, or errors in unit conversion (e.g., grams to milligrams). The participants reported that drug calculations were infrequently performed in daily practice and were rarely a topic of continuing education programs.

CONCLUSION

Similar to findings among other allied health professions, medication calculation skills were found to be lacking among a group of practicing paramedics. In addition, the paramedics reported infrequent opportunities to perform this skill in the clinical setting and that medication calculations were not a routine part of EMS continuing education programs.

Evaluation of protocols allowing emergency medical technicians to determine need for treatment and transport

OBJECTIVE

To determine whether emergency medical technicians (EMTs) can safely apply protocols to assign transport options and to assess agreement between groups of providers on application of the protocols.

METHODS

Developed protocols categorized patients as: 1) needs ambulance; 2) go to the emergency department (ED) by alternative means; 3) contact primary care provider (PCP); or 4) treat and release. After education on the application of the protocols, first responders and ambulance EMTs categorized patients at the scene prior to transport but did not change current practice. Ambulance reports were reviewed using a predetermined list of critical events that signified the need for an ambulance.

RESULTS

The EMTs categorized 1,300 study patients as follows: 1,023 (79%) needed ambulance transport, 200 (15%) could go to the ED by alternative means, 63 (5%) could contact a PCP, 14 (1%) could be treated and released. Categorizations by a first responder and the transporting EMT were compared for 209 patients. Collapsing categories to "need ambulance/do not need ambulance" showed fair concordance (kappa = 0.51). Initially, 30 of 277 (11%) patients determined not to need an ambulance appeared to experience a critical event. After review, 23 patients had events that may not warrant advanced life support transport. Seven (3%) had critical events in the ambulance warranting ambulance transport. Most were miscategorized by the EMT. Overall sensitivity and specificity for identifying patients needing ambulance transport were 94.5% and 32.8%, respectively.

CONCLUSIONS

From 3% to 11% of patients determined on scene not to need an ambulance had a critical event. Emergency medical services systems need to determine an acceptable rate of undertriage. Further study is needed to determine whether better adherence to the protocols might increase safety.

An assessment of paramedic performance during invasive airway management

OBJECTIVE

To assess the performance of paramedics, in a newly-initiated prehospital program, during invasive airway management.

METHODS

An audit of paramedic call reports for a 12-month period from January to December 1997 was performed. Call reports that documented invasive airway management were retrieved and relevant data were extracted using a preformulated data-entry form.

RESULTS

Paramedics attempted tracheal intubation in 453 patients and were successful in 408 (90.1%); 331 of the patients were in cardiopulmonary arrest with vital signs absent (VSA), 101 had medical emergencies, and 21 had trauma-related problems. In the VSA cohort, the tracheas of 96% of the patients were intubated successfully; 80.1% on the first attempt, 10.6% on the second, 4.5% on the third, and 0.9% after more than three attempts. In the medical cohort, the tracheas of 74.3% of the patients were intubated; 60.4% on the first attempt, 11.9% on the second, and 2.9% on the third. In the trauma cohort, 71.4% of the intubations were successful; 66.6% on the first attempt, 26.6% on the second, and 6.6% on the third. There was a difference (p < 0.001) in the incidence of successful intubations comparing the VSA cohort with the medical/trauma cohorts. There was also a difference (p < 0.001) between the success rate for nasal intubations (43 of 68, 63% of patients successfully intubated) and that for oral intubation (365 of 385, 94% of patients).

CONCLUSION

This study demonstrated a difference in the paramedics' success rates for tracheal intubation in VSA patients compared with those with preserved airway reflexes and a lower success rate for nasal vs oral tracheal intubation. These differences may be due to inadequate training, technical difficulties experienced in the field, or lack of sufficient exposure to medical/trauma scenarios to gain management experience. Future training to address these issues, both in the initial training phase and in the continuing education program, may be beneficial in improving performance.

EMTs' knowledge regarding transmission of infectious disease

OBJECTIVE

To describe EMTs' knowledge of CDC universal precaution guidelines and transmission routes for human immunodeficiency virus (HIV), hepatitis, meningitis, and tuberculosis (TB) and their perceived exposures to and concerns about these diseases.

METHODS

A convenience sample of EMTs were surveyed at mandatory continuing education meetings in a midwest community (pop. 523,191) between October 1 and November 30, 1996. The survey contained 101 questions about knowledge of universal precautions, transmission routes, postexposure actions, personal and family concerns, and demographics. Correct responses were based on CDC guidelines, and incorrect answers were added.

RESULTS

Four hundred of 425 surveys (94%) were returned. Eighty-one percent of the EMTs were full-time paramedics with 9.4 (95% CI 8.7-10.0%) years of experience. Seventy-five percent reported HIV, hepatitis, and TB education, while 57% reported meningitis education within the preceding year. Ninety-one percent knew universal precautions should be used with every patient. Needlestick was correctly reported as a transmission route for HIV (98%) and hepatitis (92%), but incorrectly reported for TB (37%) and meningitis (60%). Tuberculosis (94%) and meningitis (64%) were correctly identified as airborne. Thirty-four percent of the EMTs reported inadequate knowledge of infectious diseases (IDs) to protect themselves. Their perceived exposure for all four diseases ranged from 65% to 73%, but only 10-40% reported follow-up testing. Families' concern about EMTs' exposure was reported as moderate to high by 63% of the respondents.

CONCLUSIONS

There appears to be a need for continuing education for EMTs focusing on the routes of transmission of IDs, their chance of exposure, appropriate use of protective equipment, and the need for follow-up testing. This may allow more effective use of protective equipment and allay fears of EMTs and their families.

Blood loss estimation by out-of-hospital emergency care providers

OBJECTIVES

To evaluate emergency medical technicians' (EMTs') ability to estimate spilled blood volume and to determine whether limited training improves estimate accuracy and whether there is a difference in improvement comparing two different training methods.

METHODS

The study design was a single-blinded, clinical model, utilizing EMTs (basic, intermediate, and advanced) from a local commercial ambulance service. Participants estimated the volume of randomly selected volumes of packed red blood cells reconstituted to a normal hematocrit and poured onto three absorbent (carpet) and three nonabsorbent (vinyl) surfaces. Participants were then randomly assigned to one of two teaching groups. The SITEGRP (n = 17) returned to the six testing sites and were told the actual blood volumes. The SLIDE-GRP (n = 16) were taught with slides of six similar blood spill sites. Both groups were provided with suggestions for making volume estimates. The same participants were then retested one month later using the same type of sites and six new blood volumes.

RESULTS

Thirty-three participants with an average of 7.5 years of prehospital care experience completed testing on both dates. Mean percent error {[(estimated volume - actual volume)/actual volume] x 100} for all participants decreased from 65%+/-33% initially to 52%+/-20% after retesting (p < 0.05). Mean percent error was 74%+/-41% and 59%+/-20% for the SITEGRP (p < 0.15) initially and after retesting, respectively. Mean percent error was 56%+/-17% and 45%+/-17% for the SLIDEGRP (p < 0.05) initially and after retesting, respectively.

CONCLUSION

Prehospital care providers are not accurate at estimating spilled blood volumes. This ability can be improved with limited education. Slides appear to be as effective as viewing actual spill sites.

The effectiveness of lights and siren use during ambulance transport by paramedics

OBJECTIVES

To determine whether lights and siren (L&S) use during transport in the authors' EMS system results in reduced transport time to the hospital. Second, to determine whether L&S use results in any emergency department critical interventions in the time saved.

METHOD

A convenience sample of transport times were measured for 75 ambulances traveling to the hospital with L&S and compared with measured simultaneous transport times for a personal observer vehicle traveling the same route as the ambulance. Upon hospital arrival, the driver of the observer vehicle proceeded to the patients' locations and noted the medical interventions accomplished at the hospital prior to his arrival. Interventions were reviewed to identify time-critical interventions that would have been delayed without L&S use.

RESULTS

The mean ambulance transit time was 666 seconds and the mean observer transit time was 896 seconds. The mean difference in ambulance (L&S) transit time and the observer (no L&S) transit time was 230 seconds (3 min, 50 sec). There was a statistically significant correlation between transit time difference and number of stoplights encountered, traffic intensity, and distance traveled. Of the 75 patients transported, four patients were felt to have benefited clinically by the time saved.

CONCLUSIONS

Use of L&S significantly shortens transport time. In this series of patients transported under the care of a paramedic, the time saved by the use of L&S was not usually associated with immediately apparent clinical significance.