http://www.docguide.com/news/content.nsf/news/8525697700573E18852570BA004D4F9B
DALLAS, TX -- November 15, 2005 -- The ability to perform and interpret an electrocardiogram (ECG) by emergency medical service (EMS) personnel cuts the time to catheterization, length of hospital stay and mortality in patients with ST-elevation myocardial infarction (STEMI).
These findings were presented here on November 14th at the American Heart Association's Scientific Sessions 2005 (AHA).
Robert O'Connor, MD, Program Director and Director of Education and Research, Christiana Care Health System, Newark, Delaware, and colleagues assessed whether acquisition of an ECG by EMS personnel would decrease the time to treatment and overall survival in patients with STEMI.
"Early diagnosis of acute MI is a priority during the in-hospital management of the patients with chest pain in order to enable early thrombolysis," Dr. O'Connor said. "A logical extension of early diagnosis is pre-hospital recognition of the ECG criteria for thrombolysis by ambulance service paramedics."
"Pre-hospital advanced life support providers, who are already accustomed to ECG rhythm monitoring, have readily mastered the technique of performing a 12-lead ECG," he explained. "In addition, ECG evaluation of patients with chest discomfort in the out-of-hospital (EMS) setting is advocated as a Class I recommendation by the American Heart Association."
"Transmission of an ECG requires technology at both ends of the transmission, a fault-free line, the immediate availability of a senior doctor to make the diagnosis, and a system for communicating the diagnosis back to the ambulance crew," he continued. "Transmission is very likely to experience difficulties with communication, may result in delay, and requires expensive technology. Transmission problems can be avoided if the paramedic can recognize ST segment elevation."
The investigators conducted a study of 1283 consecutive patients who were transported by ambulance to a tertiary care, community teaching hospital after calling 911 with a chief complaint of chest pain.
Subjects were assigned to case or control depending on whether or not they had an ECG performed by EMS. The decision to perform a pre-hospital ECG depended on the type of EMS service or was discretionary. Paramedic or emergency physician identification of STEMI on ECG triggered immediate activation of the catheterization laboratory.
The study excluded patients who sustained a cardiac arrest prior to intervention and patients with a chief complaint other than chest discomfort.
A total of 1283 patients who had ECGs performed by EMS personnel and 269 emergency department cases were included in the analysis. For EMS ECG, there were 51 deaths (4.0%) versus 25 (9.3%) in the control group.
Mean hospital length of stay was shorter for EMS ECG cases (5.1 vs. 6.4 days). Mean time from arrival at the emergency room to admission to the catheterization laboratory (73 vs. 111 minutes, P = .0003) and mean time to balloon inflation (88 vs. 128 minutes, P < .0001) were shorter in the EMS ECG group.
Based on the results, Dr. O'Connor urged that EMS systems consider implementing pre-hospital ECG programs to decrease the time to intervention and mortality.
[Presentation title: Performance and Interpretation of the Pre-Hospital ECG by Paramedics is Associated With a Reduced Time to Intervention, Shorter Hospital Length of Stay, and Reduced Mortality. Abstract 2108]
http://www.nj.com/newsflash/health/index.ssf?/base/national-5/1131937746157310.xml&storylist=health
11/13/2005, 10:03 p.m. ET
By JAMIE STENGLE
The Associated Press
DALLAS (AP) Too busy to take a four-hour CPR course? New research shows the lifesaving procedure can be effectively taught in a little more than 20 minutes.
The finding, presented Sunday at an American Heart Association meeting in Dallas, could broadly expand the number of Americans who can perform CPR.
"It's brilliant," said Dr. Lance Becker, director of the Emergency Resuscitation Center at the University of Chicago. "I think it's going to make our ability to train people much, much easier."
The study, led by Dr. Ahamed Idris, professor of emergency medicine at the University of Texas Southwestern Medical Center in Dallas, found that just five minutes of training on defibrillator use and 20 minutes of instruction in CPR was as effective as the standard four-hour course.
Idris said it makes sense that the shorter course was just as memorable: "The more you have to remember, the more likely you are to forget," he said.
The study used American Airlines employees and compared standard training to a short course taught by DVD. Participants were tested by performing cardiopulmonary resuscitation on a computerized mannequin that took data on chest compression and ventilation. Their performance was also reviewed and graded by instructors.
The 150 people who took the short course did as well or better than the 118 who received standard training. More importantly, retention rates of knowledge remained similar six months later.
People suffering cardiac arrest can die in minutes unless they get effective CPR and sometimes a shock to the heart from a defibrillator, which restores a normal heart rhythm.
Defibrillators are becoming more common in schools, airports and other public places, but the key is having people nearby who are trained to use them.
Having a short course should help meet the heart association's goal to double in the next five years the number of Americans trained annually in cardiopulmonary resuscitation Ñ currently about 8 million. The time commitment for a four-hour course seemed to be a stumbling block in getting people trained, officials said.
"It's very difficult for a company to release their employees for four hours to take a CPR course," Idris said.
The study was funded by Laerdal Medical, maker of the training DVD, the heart association, and device maker Philips Medical.
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Wik L, Kramer-Johansen J, Myklebust H et al. Quality of Cardiopulmonary Resuscitation During Out-of-Hospital Cardiac Arrest. JAMA. 2005;293:299-304.
Although CPR guidelines recommend certain rates and ratios of ventilations and compressions, little is known about how well advanced cardiac life support personnel follow these guidelines in the field. This study aimed to measure the level of adherence to CPR guidelines in the field through a case series of 176 adult patients with out-of-hospital cardiac arrest treated by paramedics and nurse anesthetists in Stockholm, Sweden, London, England, and Akershus, Norway, over 16 months. Specially fitted defibrillators recorded the rate and depth of chest compressions through a sternal pad fitted with an accelerometer. The defibrillator was also modified to measure changes in thoracic impedance so that it could measure the rate and depth of ventilations. Chest compressions were not given 48% (95% CI, 45%-51%) of the time they should have been (when there was no spontaneous circulation). When the time required for EKG analysis and defibrillation was omitted from the calculations, thi s percentage improved to 38% (95% CI, 36%-41%). Since the mean compression rate was 121/min (95% CI, 118-124/min), this resulted in a mean rate of compressions actually delivered of 64/min (95% CI, 61-67/min). The mean compression depth was 34 mm (95% CI, 33-35 mm). Only 28% (95% CI, 24%-32%) of the compressions met the guideline of 38 mm to 51 mm deep. Providers delivered a mean of 11 (95% CI, 11-12) ventilations per minute. Sixty-one patients (35%) had return of spontaneous circulation, and 5 of 6 patients discharged alive from the hospital had normal neurological outcomes.
Comment: This is a groundbreaking study with novel methodology and far-ranging implications. If the CPR guidelines are valid (i.e., if they are the best way to achieve discharge alive with good neurological condition), then patients appear not to be getting the care they should. Since there have been no human studies comparing the effect on survival of different ventilation and compression rates and ratios, this remains an open question. The study results suggest several other questions: Are human beings physically able to meet the guidelines (either current or proposed)? If so, why are they not doing so? How should they be taught and evaluated?
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Abella BS, Alvarado JP, Myklebust H et al. Quality of Cardiopulmonary Resuscitation During In-Hospital Cardiac Arrest. JAMA. 2005;293:305-310.
This study had the same engineer as the out-of-hospital CPR study, so the authors used the same defibrillator modified to measure ventilation and compression rate and depth, but this time in an in-hospital setting. Chest compressions were too slow (less than 90/min) 28.1% of the time and too shallow 37.4% of the time. The hospital personnel ventilated too fast (more than 20/min). Chest compressions were not given 24% of the time they should have been. Subtracting 10 seconds each minute for pulse checks would still result in no compressions 17% of the time they should been delivered. In all, 27 patients (40.3%) had a return of spontaneous circulation and 7 (10.4%) were discharged from the hospital.
Comment: It seems that CPR in hospitals leaves something to be desired, too. It is difficult to compare in-hospital and out-of-hospital results because although these two studies appeared in the same issue of JAMA, two different groups conducted the studies and used different outcome measures. Here are some of the results that seem to be comparable.
Out-of-hospital (Europe) In-hospital (Chicago)
time without compressions* 49% 24%
mean compression rate 120/min 102/min
mean compressions actually delivered in one minute 60 78
mean compression depth 35 mm 42 mm
mean ventilations/minute 8 21
compressions too shallow 50% 37%
*Figures not corrected for time required to analyze EKG, defibrillate or move patient. With the recent emphasis on compressions in CPR, we can expect to see these studies cited frequently. It will be interesting to see whether delivering more compressions actually results in greater survival or just makes certain physiological parameters look better. The out-of-hospital ventilation rate of 8 per minute seems remarkable, especially compared to a study in Milwaukee, Wisconsin, where paramedics ventilated cardiac arrest patients more than 30 times per minute at the beginning of the study and still ventilated more than 20 times per minute after the study was halted to allow for retraining of the paramedics (see the next two papers).
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Aufderheide TP, Lurie KG. Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Crit Care Med. 2004 Sep;32(9 Suppl):S345-51. After observing paramedics consistently hyperventilating patients in out-of-hospital cardiac arrest, these researchers hypothesized that excessive ventilation rates during CPR causes a significant decrease in coronary perfusion pressure and a decreased chance of survival. In the first part of the study, the authors recorded ventilation rate and duration during CPR by paramedics treating intubated, adult patients. In the second part of the study, to determine the effects of hyperventilation, they ventilated nine pigs in cardiac arrest with 12, 20, or 30 breaths/minute and monitored several physiologic variables. They then ventilated three groups of seven pigs in cardiac arrest in one of three ways: 12 breaths/min with 100% oxygen, 30 breaths/min with 100% oxygen, or 30 breaths/min with 5% CO2/95% oxygen. In the first 13 adults paramedics administered CPR to, the mean ventilation rate was 37 +/- 4 breaths/min (range, 19 to 49 breaths/min). Positive pressure was present in the l ungs for a mean time of 47.3 +/- 4.3%. No patient survived. After the researchers re-trained the paramedics, mean ventilation rate decreased to 22 + 3 breaths/minute. In animals treated with 12, 20, and 30 breaths/min, the mean coronary perfusion pressures were 23.4 +/- 1.0, 19.5 +/- 1.8, 16.9 +/- 1.8 mm Hg (p = .03). Six of seven pigs in the 12/min group survived, one of seven pigs in the 30 breaths/min group survived and one of seven pigs in the 30 + CO2 breaths/min group survived (p = .006).
Comment: See the comment on the next paper.
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Aufderheide TP, Sigurdsson G, Pirrallo RG et al. Hyperventilation-induced hypotension during cardiopulmonary resuscitation. Circulation. 2004 Apr 27;109(16):1960-5. Epub 2004 Apr 5.
Comment: Abstracts are not provided for both of these papers because they are the same paper. There are some minor variations in the write-up, but the subjects, the methods and the results are all the same. The Critical Care Medicine paper is part of the proceedings of the Wolf Creek conference.
These results are alarming. Paramedics ventilated patients in cardiac arrest 37 times a minute and, even after re-training, still ventilated 22 times per minute, almost twice the recommended rate. Evidence clearly indicates that hyperventilating patients is almost always bad. Perhaps we need to work on not just the knowledge and skills of EMS providers when it comes to ventilation, but also attitudes. Some EMS providers seem to believe that “if some is good, more is better.” Not only is this incorrect, but in some cases, it is harmful to the patient.
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Jacobs IG, Finn JC, Oxer HF, Jelinek GA. CPR before defibrillation in out-of-hospital cardiac arrest: a randomized trial. Emerg Med Australas. 2005 Feb;17(1):39-45.
These Australian authors randomized prehospital cardiac arrest patients to receive either 90 seconds of CPR before defibrillation (treatment) or immediate defibrillation (control) between June 2000 and June 2002. In all, 256 patients were randomized. In the CPR first group. 4.2% (5/119) survived to hospital discharge compared with 5.1% (7/137) for the immediate defibrillation group (OR 0.81; 95%CI. 0.25-2.64). When they looked at secondary endpoints of the study, the researchers found no difference in the proportion of patients who had a return of spontaneous circulation (OR 1.16; 95% CI 0.49-2.80).
Comment: The results of this paper are in conflict with one retrospective study in King County, Washington (Cobb LA, Fahrenbruch CE, Walsh TR et al. Influence of cardiopulmonary resuscitation prior to defibrillation in patients with out-of-hospital ventricular fibrillation. JAMA. 1999 Apr 7;281(13):1182-8.) and a randomized controlled trial in Norway (Wik L, Hansen TB, Fylling F et al. Delaying defibrillation to give basic cardiopulmonary resuscitation to patients with out-of-hospital ventricular fibrillation: a randomized trial. JAMA. 2003 Mar 19;289(11):1389-95.) Why are these results different? It’s hard to say. Perhaps if funding had not run out and the researchers had been able to recruit all the patients they had planned to, a difference might be apparent. Perhaps response times were too long. Perhaps three minutes of CPR is required to see a difference (as done in the paper by Wik et al). The authors do note that their usual resuscitation rate of about 10% of VF patien ts was cut in half with this series of patients. On the other hand, perhaps there is no improvement with CPR before defibrillation and the first two papers on this subject were flukes. Whatever the reason, we should be cautious in changing our current practice of defibrillate first. It is unclear whether some patients benefit from early CPR, as suggested by the two other papers.
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Davidovic L, LaCovey D, Pitetti RD. Comparison of 1-person versus 2-person bag-valve-mask techniques for manikin ventilation of infants and children. Annals Emerg Med 2005 July;46(1):37-42. These researchers compared the ability to ventilate infant and child manikins of ten volunteers in each of seven groups: first, second and third year pediatric residents, second year emergency medicine residents, pediatric emergency nurses, paramedics and interfacility transport personnel. No group was able to ventilate the infant manikin adequately (at least 10 mL/kg) when subjects worked alone. Paramedics were the only group to provide sufficient volume with one-person ventilation of the child manikin and two-person ventilation of the infant and child manikins. Although subjects ventilated better when working in pairs, except for the paramedic group, they still did not provide sufficient volume to meet current guidelines.
Comment: Finally, some good news about EMS providers and their ability to ventilate well. This study is reassuring, showing that paramedics can generate the necessary volumes for ventilation of children and infants, in contrast to all the other groups studied. Of course, this must be tempered with the realization that the recommended volume of 10 mL/kg may be reduced later this year when the American Heart Association releases its recommendations and guidelines. This study also showed not only that it was difficult to ventilate an infant or child manikin without assistance, but that the 2-person technique does lead to better ventilation volumes, a finding parallel to that of adults. One parameter that was not measured was ventilation rate. If paramedics ventilate adults 30 times a minute, how fast are they ventilating infants and children?
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Davis DP, Peay J, Sise MJ et al. The impact of prehospital endotracheal intubation on outcome in moderate to severe traumatic brain injury. J Trauma. 2005 May;58(5):933-9. These researchers from San Diego identified and reviewed patients with moderate to severe traumatic brain injury from their county trauma registry. They used logistic regression to determine the association between prehospital intubation and outcome, controlling for age, gender, mechanism, several types of trauma scores and hypotension. They also used neural network analysis to see if there were any patients who might be expected to benefit from prehospital intubation. Of the 13,625 patients reviewed, 22.9% died and 19.3% had prehospital intubation. There was decreased survival in patients who were intubated prehospital (odds ratio, 0.36; 95% confidence interval, 0.32-0.42; p < 0.001). Patients intubated prehospital fared worse than those intubated in the emergency department. Neural network analysis found a subgroup of patients with more significant injuries that might benefit from prehospital intubation.
Comment: The title of this paper is somewhat misleading. “Impact” is a very strong word and one that cannot be justified in this context. A retrospective review of a trauma registry can reveal important relationships, but “impact” implies causation, though not overtly. Causation is often difficult to demonstrate, especially with retrospective reviews. It is much more accurate with this study type to claim an association between certain factors. The authors acknowledge this in the body of the paper and their conclusion when they use the words "association" and "associated" to describe their findings. Tables 1, 2 and 3 in the paper all present data on biceps long head tendon lesions. This is undoubtedly a fascinating topic (for someone), but it appears there was a printing error and somehow the data for another paper slipped into the space for this paper’s data. Without the information from the tables it is difficult to evaluate all aspects of the paper. There is probably enough left, however, to draw some conclusions. The time period of the study, 1/1/87 to 12/31/03, is concerning. This is a period during which a lot of changes occurred in EMS. Eighteen year old data may not reflect the reality of today. The paper does not provide any information on how many cases occurred during which years. There is no mention of excluding the patients from the San Diego RSI study. In fact, the methods section specifically states, “The present analysis included all patients in the San Diego TBI Database treated between January 1, 1987, and December 31, 2003.” This would seem to bias the data for at least two reasons. First, these patients have already been studied and found to have suffered from intubation associated with paralytic drugs when there was not constant monitoring of ETCO2 and pulse oximetry. Second, RSI and ETI without paralytics are very different beasts. There are enough differences between the techniques, indications and complications to justify separating the data between RSI and non-RSI patients. If the study looked at only non-RSI patients, the methods section needs to be revised. This paper does not answer the question of whether prehospital intubation causes decreased survival. This is similar to (though not the same as) a study a few years ago that found cardiac arrest patients who got more epinephrine had worse outcomes than those who got little or no epi. This is no surprise since patients who do not respond receive more epinephrine as a result. That was a much clearer example of how association can be confused with causation. This paper is by no means exactly analogous, but the perils of accounting for risk factors and overstating conclusions are significant. This paper has generated a hypothesis that needs to be evaluated further, preferably by means of randomized controlled trials. Until that happens, we will need to piece together all the data available and interpret them the best we can.
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Shy BD, Rea TD, Becker LJ, Eisenberg MS. Time to intubation and survival in prehospital cardiac arrest. Prehosp Emerg Care. 2004 Oct-Dec;8(4):394-9. This retrospective study evaluated 693 cardiac arrest patients who were intubated by paramedics in King County, Washington (excluding Seattle), over a thirteen year period. In the patients who were intubated quickly (intubation time < 12 minutes), 46% survived. In the patients who were not intubated within 12 minutes, 23% survived. After using logistic regression to adjust for age, sex, location, bystander CPR, cardiac rhythm, EMT response time, and paramedic response time, the researchers found an adjusted odds ratio of survival for the slow intubation group compared with the quick intubation group to be 0.42 (95% confidence interval 0.26, 0.69).
Comment: This is another paper that treats association and causation as almost equivalent. There are many possible reasons why some patients might be intubated late that would confound the results. This is another paper that is suggestive, but not conclusive. The authors acknowledge this in calling for prospective studies on this topic.
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Pratt JC and Hirshberg AJ. Endotracheal Tube Placement by EMT-Basics in a Rural EMS System. Prehosp Emerg Care 2005 April-June; 9(2): 172 - 175 This was an uncontrolled trial over a four-year period of intubation attempts by EMT-Basics trained under a special-waiver project. The training of the EMT-Basics included operating room intubations. The authors defined an intubation attempt as direct laryngoscopy and a successful attempt as an appropriately sized ETT placed and secured in the trachea below the vocal cords and above the carina. EMT-Bs completed 32/34 (94%) intubations on adults in cardiopulmonary or respiratory arrest. The researchers found no unrecognized esophageal tubes.
Comment: This program was very selective: of the 40 EMTs who applied to the program, eight were accepted and only four finished. Students completed classroom and lab training and also had to perform ten intubations in the O.R. There were also four paramedics and one EMT-I on the island who were not allowed to practice beyond the EMT level until this pilot program because of licensure issues. Their intubations were not included in the analysis (appropriately), but it is unclear how much informal support and vicarious experience they provided to the EMTs. Although this study showed EMT-Bs could intubate when the medical director carefully selected them, provided them with classroom instruction and significant O.R. exposure and conducted quarterly review and evaluation sessions, there was little to show for improved outcome. One respiratory arrest patient survived and one cardiac arrest patient may have survived over four years. How many medical directors are willing to make suc h an investment of resources for so little, if any, change in patient outcome?
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Bulger EM, Copass MK, Sabath DR et al. The use of neuromuscular blocking agents to facilitate prehospital intubation does not impair outcome after traumatic brain injury. J Trauma 2005 Apr;58: 718-24. These King County, Washington, researchers identified head injury patients admitted to their trauma registry over a five and a half year period. After stratifying patients by their prehospital GCS scores into mild, moderate and severe categories, they evaluated survival and good outcome (defined as survival to discharge with a GCS score of 14/15). Of the 3,052 patients, complete prehospital data were available for 2,012 patients (66%). Of the 920 mild TBI patients, 17.4% were intubated; of the 293 moderate TBI patients, 57.7% were intubated; and of the 799 severe TBI patients, 95% were intubated. Paramedics used neuromuscular blocking agents (NMBAs) on 72% of the intubated patients. The only differences found between the NMBA and no-NMBA groups were that patients not receiving NMBAs were more likely to be hypotensive and have CPR (p = 0.001). The crude mortality rate for the patients intubated with NMBAs was 25% versus 37% for those not receiving NMBAs (p < 0.001). After acc ounting for potential confounders, the authors found that patients who received NMBAs were more likely to survive (odds ratio of death, 0.63; p = 0.04) and to have a good outcome (odds ratio, 1.7; 95%; p = 0.006).
Comment: This is another retrospective review of a trauma database that attempts to determine the effects of prehospital RSI. The authors attempted to control for confounding variables, but did not have complete data for one-third of the patients. This paper suggests a benefit to prehospital RSI, but a randomized trial would give a more reliable and comprehensive answer to this question.
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Colwell CB, McVaney KE, Haukoos JS et al. An evaluation of out-of-hospital advanced airway management in an urban setting. Acad Emerg Med 2005 May;12(5): 417-22. After seeing several studies describing poor intubation performance by paramedics, the authors, from Denver Colorado, decided to evaluate the success and complication rates associated with endotracheal intubation in their system by means of a retrospective chart review. During the study period (March to May 2001) paramedics attempted intubation on 278 patients. More than half the intubations were nasal (154 (55%)) with the remaining 124 oral (45%). Paramedics were successful with 234 (84%, 95% CI = 77% to 88%). Two of the nasal tubes were misplaced (2%; 95% CI = 0.2% to 6%) and one of the 120 oral intubations (1%; 95% CI = 0.02% to 5%) was misplaced. Of the three misplaced tubes, two (0.7%; 95% CI = 0.08% to 3%) were in the esophagus and one (0.4%; 95% CI = 0 to 2%) was in the posterior pharynx. There were 22 complications in the 278 patients (8%; 95% CI = 5% to 12%). All intubations were performed without neuromuscular blocking agents or other medications.
Comment: In contrast to other studies that have found unrecognized endotracheal tube misplacement up to 25% of the time, this study found a 1% misplacement rate. The authors suggest that their system’s success may be related to the relatively small number of paramedics who average around ten intubations a year, the small number of EMS agencies (two) in the area and strong medical direction. Of note, this system often uses the blind nasotracheal route (more than half the time) and does not use rapid sequence intubation.
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Domeier RM, Frederiksen SM, Welch K. Prospective Performance Assessment of an Out-of-Hospital Protocol for Selective Spine Immobilization using Clinical Spine Clearance Criteria. Annals Emerg Med 2005 Aug; 46(2):123-131. These researchers trained EMS providers to perform and document a spine injury assessment for trauma patients. The assessment included these clinical criteria, based on the NEXUS study: altered mental status, evidence of intoxication, neurologic deficit, suspected extremity fracture and spine pain or tenderness. Outcome measures were the presence or absence of spine injury and whether EMS providers immobilized the spine. Of 13,357 patients for whom complete data was available, there were 415 (3%) with spine injuries, including 50 with spinal cord injuries and 128 with cervical injuries. Providers were 92% sensitive (95% confidence interval [CI] 89.4 to 94.6%) in detecting spine injury, resulting in lack of immobilization in 8% of the patients with spine injuries (33 of 415). None of the these patients had cord injuries. The specificity (ability to exclude those who did not need immobilization) was 40% (95% CI 38.9 to 40.5%).
Comment: A number of EMS systems have adopted spine clearance criteria without evidence to support such activities. This study is the largest of its kind to date and helps to answer some of the questions relevant to such protocol changes. A sensitivity of 92% with a 95% confidence interval of 89.4% to 94.6% is not very comforting, however, given the devastating nature and lifelong effects of a spinal cord injury. Even though this study evaluated more than 13,000 patients, we should keep in mind that the NEXUS study of emergency physicians from which these criteria have been extrapolated involved more than 30,000 patients. When only 12% of the spine injury patients have spinal cord injuries (one out of eight), a very large study is necessary to insure a small enough 95% confidence interval.
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Wang HE, Reitz SR, Hostler D, Yealy DM. Defining the Learning Curve for Paramedic Student Endotracheal Intubation. Prehosp Emerg Care 2005 April-June; 9(2): 156-162. The authors examined the relationship between paramedic students’ cumulative live intubations, time lapsed since beginning intubation training and clinical setting and intubation success. The data, from 802 students in 60 paramedic training programs, allowed them to evaluate the students’ first 30 intubation attempts. The researchers adjusted for clinical setting, elapsed number of days from the first intubation encounter and the interaction between cumulative intubations and elapsed days. They then constructed probability plots to show the “learning curve.” The students were successful in 6,464 of 7,635 intubation attempts (87.4%). Most (82.7%) were done in the OR, with 3.6% in the ED, 0.8% in the ICU, 1.1% in other in-hospital settings, and 11.8% in the prehospital arena. Logistic regression revealed an odds ratio for success of 1.067 per intubation (95% CI: 1.044–1.091). In other words, for each intubation a student had performed, the odds of success on the next attempt in creased by a factor 1.067. For example, the odds of success would be 1.914 after ten successful intubations (1.06710). Probability of successful Intubation in the ICU and prehospital settings was lower than for other environments, but learning occurred more quickly there, i.e., the learning curve was steeper. Elapsed time did not appear to be a significant factor in predicting success.
Comment: This study lays the groundwork for further work in this important area. Similar research has been done for other professions and it is long overdue in EMS. Once a few more studies like this have taken place, we will be able to have a defensible minimum number of ETIs a paramedic student needs to accomplish before the end of training.
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Ruple JA, Frazer GH, Hsieh AB, Bake W, Freel J. The State of EMS Education Research Project: Prehosp Emerg Care 2005 April-June; 9(2):203-212. EMS educators and the educational infrastructure they have to work with have not been characterized before now. This survey of 1,691 instructors found that they were satisfied with their teaching experience to date (98%), expected to continue teaching (80%), and became instructors because they believed there was a shortage of qualified instructors. Half of the respondents reported using national standard curricula and about one-fifth expressed some level of discomfort with assessment of psychomotor skills.
Comment: This paper is a result of a NHTSA contract with NAEMSE which the Council assisted in. Every training coordinator should read this paper in its entirety to see just who is teaching EMS courses, what resources they have (and don’t have), how long they plan to continue teaching and many other things.
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Roberts I, Yates D, Sandercock P et al for the CRASH trial collaborators. Effect of intravenous corticosteroids on death within 14 days in 10,008 adults with clinically significant head injury (MRC CRASH trial): randomised placebo-controlled trial. Lancet 2004; 264: 1321-28. Although corticosteroids have been used for many years to treat serious head injuries, the evidence of benefit has been weak. This trial, which took place in 49 countries, was conducted to determine whether this practice should continue. It was stopped early (after 10,008 patients instead of the planned 20,000) because the interim analysis showed a clear harmful effect of steroids. Eligible patients were adults who had a GCS <14 and presented <8 hours post-injury. After randomization, patients in the treatment group received methylprednisolone; patients in the control group received an identical-appearing placebo. The primary outcome of death from any cause at two weeks was higher in the treatment group (21.1% vs. 17.9%). The relative risk of death from treatment with steroids was 1.18 (95% CI 1.09-1.27); p=0.0001.
Comment: This very impressive trial should put to rest the belief that head injury patients should receive steroids. The methodology of this study is quite impressive and worth reading to see how to conduct a randomized double-blind placebo-controlled trial. One slight weakness of this report is that the researchers could not determine the cause of death. This was a result of the different resources available in the 239 hospitals around the world that participated. Nonetheless, there are many strengths to recommend this report.
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Transmission of Hepatitis B Virus Among Persons Undergoing Blood Glucose Monitoring in Long-Term--Care Facilities --- Mississippi, North Carolina, and Los Angeles County, California, 2003—2004. MMWR March 11, 2005 / 54(09);220-223. This report from CDC describes three long-term-care facilities where residents contracted HBV because of shared blood glucose measuring devices and equipment. Recommendations regarding standard precautions and avoiding the reuse of fingerstick devices have not been observed consistently in these facilities.
Comment: Although this paper may seem to have no relevance for EMS, it is not that difficult to imagine an EMS agency with poor management and medical direction performing the same activities that led to unnecessary hepatitis B infections for these nursing home patients. Any EMS providers who think that lancets can’t spread infection will need to be re-educated.
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Oxman MN, Levin MJ, Johnson GR et al for the Shingles Prevention Study Group. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N Engl J Med. 2005 Jun 2;352(22):2271-84. These authors evaluated the ability of a vaccine against varicella-zoster virus (VZV) to reduce the incidence, severity, or both of herpes zoster and postherpetic neuralgia among older adults. The researchers enrolled 38,546 adults 60 years of age or older in a randomized, double-blind, placebo-controlled trial and measured the pain and discomfort associated with herpes zoster for six months. There were twice as many cases of herpes zoster among placebo recipients compared to vaccine recipients (642 vs. 315). There were more than twice as many cases of postherpetic neuralgia among placebo recipients compared to vaccine recipients (80 vs. 27). The vaccine reduced the burden of illness attributable to herpes zoster by 61.1 percent (P<0.001), reduced the incidence of postherpetic neuralgia by 66.5 percent (P<0.001), and reduced the incidence of herpes zoster by 51.3 percent (P<0.001).
Comment: Shingles is not usually considered a life-threatening illness, but it can be quite debilitating. Although it strikes the elderly more often than other age groups, young and middle-aged adults are not invulnerable. This may become a common vaccination for adults in the future.
Research Methodology
Montori VM, Jaeschke R, Schünemann HJ et al. Users' guide to detecting misleading claims in clinical research reports. BMJ 2004;329:1093-1096.
Many articles in the scientific literature describe means by which readers can detect poorly conducted studies. There is little available to assist the reader in evaluating well done studies that when written up make misleading claims.
Comment: Unfortunately, scientific reports are not completely objective and free of bias. This article gives concrete recommendations on how to avoid being bamboozled.
Keim SM, Spaite DW, Maio RF et al. Risk adjustment and outcome measures for out-of-hospital respiratory distress. Acad Emerg Med. 2004 Oct;11(10):1074-81. This is another paper produced by the investigators working on the EMS Outcomes Project (EMSOP). In the fifth paper from this group, the authors evaluated the literature and consulted an expert panel on risk-adjustment and outcome measures for EMS research on respiratory distress patients. The recommended measures are pulse oximetry, peak expiratory flow rate, the visual analog dyspnea scale and mortality.
Comment: If EMS is ever going to get serious about reporting outcomes other than life and death, this is the kind of information that will be needed to do it. Risk-adjustment measures allow researchers and readers to make comparisons that are adjusted for factors like severity of illness.
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Pirrallo RG, Levine R, Dickison PD. Behavioral health risk factors of United States emergency medical technicians: the LEADS Project. Prehospital Disaster Med. 2005 Jul-Aug;20(4):235-42. Researchers from the Longitudinal EMT Attribute and Demographic Study (LEADS) compared the self-reported health risk behaviors of EMTs to the general public. Comparison of 1,919 EMTs to more than 200,000 Behavioral Risk Factor Surveillance System (BRFSS) respondents and more than 5,000 Motor Vehicle Occupant Safety Survey (MVOSS) respondents showed that EMT-Basics drove more slowly than paramedics. Female EMTs drove slower, drank less and wore their seatbelts more often than male EMTs, but smoked more and engaged in vigorous exercise less than males. EMTs who reported they were in fair or poor health smoked more and exercised less than other EMTs. In general, EMTs wore their seatbelts less often, drove faster than, and were less likely to engage in moderate physical exercise than US adults.
Comment: This study confirms a number of suspicions about EMS providers. Now that we know they engage in higher risk behaviors, it is up to the EMS community to do something about it.
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Brown WE Jr, Margolis G, Levine R. Peer evaluation of the professional behaviors of emergency medical technicians. Prehospital Disaster Med. 2005 Mar-Apr;20(2):107-14. In a LEADS survey sent to 2,443 EMTs, participants rated their EMT partners (defined as the one with whom they worked most closely in the past year). The survey was returned by 1,510 respondents (61.8%). On a scale of 0 to 1 with 1 being the highest rating possible, the overall average score was 0.68. In descending order, participants assigned their partners these scores: integrity (0.77), appearance/personal hygiene (0.74), patient advocacy (0.73), empathy (0.72), self-confidence (0.70), careful delivery of service (0.70), respect (0.65), communication skills (0.64), time management skills (0.63), teamwork/diplomacy skills (0.62) and self-motivation (0.61). Paramedics gave their partners significantly lower scores than EMTs (p = 0.0156) and experienced EMTs gave their partners lower scores than newer EMTs (p = 0.0002). EMTs who were more satisfied with their current EMS assignment rated their partner higher than did EMTs who were less satisfied.
Comment: Although integrity and appearance/personal hygiene ranked highest, there isn’t much difference in the ratings overall. Possible explanations for the differences in scores are that experienced providers may be more cynical than new providers and that paramedics may be more competitive than EMTs.
O’Keefe MF, Levine R. Terrorism response training for emergency medical technicians since September 11, 2001: A nation unprepared [abstract]. Ann Emerg Med. 2004; 44(4); S104. This abstract from the LEADS project looked at responses from 510 EMT-Bs and 862 EMT-Ps who were asked about their reactions to the events of September 11, 2001 and training in terrorism response since then. EMT-Bs were less likely than EMT-Ps to report they had received training in use of an air purifying respirator (30% vs. 45%), recognition of nuclear, biological and chemical (NBC) hazards (67% vs. 79%) and use of personal protective equipment against NBC hazards (59% vs. 65%). A surprising number of EMT-Bs and EMT-Ps (23% and 15%) reported receiving no training in PPE use or recognition and treatment of hazardous material exposures. The median number of hours of such training was less than one hour for EMT-Bs and between one and four hours for EMT-Ps. Less than one hour of training was received by 51% of all EMTs.
Comment: The most interesting (and alarming) finding of this study is that half of EMTs in this country received less than one hour of training on responding to terrorism in the two years after September 11, 2001. Now that some federal grant money has been dedicated to EMS, it will be interesting to see if this changes. A follow-up survey in a few years could be quite revealing.
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Oxman AD, Chalmers I, Liberati A. A field guide to experts. BMJ. 2004 Dec 18;329(7480):1460-3.
Comment: The last issue of the BMJ every year has a number of papers that are intended to be strictly entertaining. Although this paper is very amusing, it also has some pearls about recognizing different types of “experts.”
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