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Outcome from cardiopulmonary resuscitation (CPR) at community hospitals is seldom reported in the literature. Data regarding long-term functional status of CPR survivors are virtually nonexistent. We retrospectively reviewed the medical records of all patients receiving CPR during 1989 at a community teaching hospital to determine survival to hospital discharge from CPR. Long-term functional status was determined by contacting primary care physicians in January 1992. We found 24 of 83 (29 percent) patients survived in-hospital CPR and were discharged. Follow-up of these 24 patients showed 13 (54 percent) were alive a mean of 31 months postdischarge with 10 of the 13 (77 percent) reported to be living independently. We believe survival from CPR at community teaching hospitals is comparable to university hospitals. Additionally, patients who survive in-hospital CPR to hospital discharge have a 54 percent chance of being alive a mean of 31 months postdischarge with most being able to live independently. Further work is needed to validate these long-term functional status results.

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To evaluate the recently published Utstein algorithm (Ann Emerg Med 1991;20:861), the authors conducted a retrospective review of all advanced life support (ALS) trip sheets and hospital records of patients with prehospital cardiac arrests between January 1988 and December 1989. Telephone follow-up was used to determine 1-year survival rates. Of 713 arrests in the 24-month study period, 601 were of presumed cardiac etiology. Approximately 599 of these charts were available for analysis. One hundred ninety-three (32.2%) of these had return of spontaneous circulation (ROSC), 36 (6.0%) survived to hospital discharge, and 24 were alive at 1-year follow-up (4.0% of total or 67% of survivors to discharge). The Utstein style was found to be a useful algorithmic format for reporting prehospital cardiac arrest data in a manner that should allow direct comparison between emergency medical service (EMS) systems. Existing prehospital record-keeping practices (trip sheets) are easily adapted to this style of data collection, although certain data for the template (eg, resuscitations not attempted and alive at 1-year) are more difficult to ascertain. Additionally, the authors report their own experience during a 2-year period, including data that suggest that the majority of patients with cardiac arrest who survive to hospital discharge are still alive at 1 year.

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OBJECTIVE: A variety of methods are used to calculate indices of lung mechanics. We conducted this study to compare 6 methods of calculating airway resistance. METHODS: Data were recorded from 20 adult mechanically ventilated patients. All were relaxed and breathing in synchrony with the ventilator, and an end-inspiratory pause sufficient to produce a pressure plateau (0.5-1.5 s) was used. Pressure and flow rate were measured at the proximal airway using a calibrated lung mechanics analyzer (VenTrak, Med Science, St Louis, MO). Flow rate, pressure, and volume were printed simultaneously. Airway resistance was calculated using 6 methods: Suter, Krieger, Neergard, Bergman, Comroe, and Jonson. RESULTS: Mean calculated resistances (+/- SD) (cm H2O/L/s) were 11.7 +/- 4.8 (Suter method), 13.3 +/- 5.0 (Krieger method), 14.9 +/- 5.3 (Neergard method), 25.0 +/- 6.6 (Bergman method), 24.7 +/- 6.4 (Comroe method), and 26.9 +/- 4.8 (Jonson method). By repeated measures analysis of variance, these differences were significant (p < 0.001). Using Scheffe analysis, no difference was found between the calculations using the Bergman, Comroe, and Jonson methods; these were significantly greater than the other 3 methods (p < 0.05). CONCLUSIONS: Methods that evaluate expiratory resistance (Comroe, Bergman, and Jonson) produce higher values than methods that evaluate inspiratory resistance (Suter and Neergard) or a combination of inspiratory and expiratory resistance (Krieger). Because of these differences, investigators should clearly describe their calculations when reporting airway resistance values.

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Many studies have shown improved survival of cardiac arrest patients by the use of early defibrillation (EMT-D) in the field. This prospective study was the first in Pennsylvania and was undertaken to determine if an EMT-D program would be successful in our suburban/rural setting. One hundred two EMTs were trained to use a semi-automatic defibrillator and data were collected over 16 months. There were 96 cardiac arrests, with only 33 patients (34%) presenting with initially treatable dysrhythmias--ventricular fibrillation (VF) or tachycardia (VT). Twenty-three patients (24%) were admitted to the hospital; survival to hospital discharge occurred in only 5 patients (5.2%). Survival to hospital admission was higher among VF/VT presenting rhythms (36%) than for those with other rhythms (17%, P = 0.07), but survival to discharge among VF/VT rhythms (9%) was not statistically different from other rhythms (3%, P = 0.45). Among VF/VT patients, survival to discharge was correlated with shorter call to first defibrillation intervals. Mean call to response interval was longer than in other reported studies (7.2 +/- 4.3 minutes). In addition, there was a high drop-out rate of EMT participants, no central/uniform early access system (that is, 911), and a lower rate of CPR than reported in other studies. It is concluded that introduction of an EMT-D program without careful analysis of systems response factors will not lead to the improved cardiac arrest survival percentages that have previously been reported.

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UNLABELLED: We conducted this study to determine the inspiratory and expiratory flow resistance of the valves of eight commercially available mouth-to-mask ventilation devices. METHODS & MATERIALS: We evaluated the valves of Intertech, Laerdal, Life Design Systems (LDS), Res-Q, Respironics, Rondex, Vital Signs, and White. The devices were supplied by the manufacturers and included the valve and any filter or extension tube supplied with the valve. Expiratory resistance was evaluated by directing air through the valve in the direction of flow when the patient exhales. Inspiratory resistance was evaluated by directing air through the valve in the direction of flow when a breath is delivered to the patient. Flow was controlled by a Timeter 0-75 flowmeter and measured using a calibrated Timeter RT-200. Flows of 10, 20, 30, 40, 50, 60, 70, 80, and 90 L/min were used. 'Back' pressure due to the resistance of the valves was measured using a calibrated Timeter RT-200. Resistance was calculated by dividing back pressure by flow. Five measurements were made at each flow setting for each valve. RESULTS: We observed significant differences in back pressures and resistances between the flows evaluated (p < 0.001 for both inspiratory and expiratory flows), and between the commercially available devices (p < 0.001 for both inspiratory and expiratory flows). At a flow of 50 L/min, the inspiratory back pressures produced by the devices were [mean (SD) in cm H2O] Intertech 5.2 (0.06), Laerdal 4.6 (0.09), LDS 4.7 (0.03), Res-Q 3.1 (0.04), Respironics 3.3 (0.04), Rondex 1.1 (0.02), Vital Signs 4.0 (0.06), and White 4.3 (0.10). At this same flow, the expiratory back pressures were Intertech 4.8 (0.30), Laerdal 9.1 (0.10), LDS 3.3 (0.02), Res-Q 3.7 (0.35), Respironics 0.5 (0.01), Rondex 1.4 (0.01), Vital Signs 3.6 (0.05), and White 13.7 (0.48). CONCLUSIONS: In some cases, the resistance through these devices might be considered excessive; however, most of the devices meet the International Standards Organization (ISO) standard (back pressure < 5 cm H2O at 50 L/min).

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INTRODUCTION: Airway management is the most critical and potentially life-saving intervention performed by emergency medical service (EMS) providers. Invasive airway management often is required in non-cardiac-arrest patients who are combative or otherwise uncooperative. The success of prehospital invasive airway management in this patient population was evaluated. METHODS: A retrospective review was undertaken of the records of all such patients requiring endotracheal intubation over a three-year period (1987-1989). The study population included 278 patients enrolled by five advanced life support (ALS) units serving a suburban population of 425,000. Field trip sheets were reviewed for diagnosis, intubation method and success, number of intubation attempts, provider experience, reasons for unsuccessful intubations, and complications. RESULTS: A total of 394 invasive airway management attempts were performed on 278 patients. The overall successful intubation rate was 75% (41% orotracheal, 52% nasotracheal, 7% other or unknown). The most common diagnoses were COPD and pulmonary edema (30%) and trauma (24%). Experienced providers were successful on the first attempt in 57% of cases compared to 50% by inexperienced providers (p=.24). Multiple intubation attempts were required in 33% of the patients. There was no statistically significant difference in success rates between the orotracheal and nasotracheal methods (p=.51). The most common reason for unsuccessful intubation was altered level of consciousness. Complications occurred with 7% of successful attempts and in 18% of unsuccessful attempts (p less than .001). Forty-six percent of the patients who were not intubated successfully in the field and required intubation in the emergency department (ED) received a neuromuscular blocking agent prior to successful intubation. CONCLUSION: Prehospital providers can intubate a high but improvable proportion of non-cardiac-arrested patients by both the orotracheal and nasotracheal routes. The use of pharmacologic adjuncts to facilitate the prehospital intubation of selected, non-cardiac-arrested patients is a promising adjunct that needs further evaluation.

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UNLABELLED: Although the concept of ventilator circuit compression is well known, it is not fully appreciated clinically. We compared the compression volume of five adult disposable ventilator circuits and a nondisposable circuit. METHODS: Five brands of disposable circuits (Inspiron, Intertech, Marquest, Seamless, and U-Mid) and one nondisposable brand (Bennett) were used. The circuits were attached to the outlet of a Bennett MA-1 ventilator in the standard manner, and the filter and humidifier were bypassed to eliminate their contribution to compression volume. The ventilator delivered 1 L of gas to a Michigan Instruments Test Training Lung at a flow of 60 L/min and a rate of 12/min. A valve system was placed between the Y-connector and the TTL to partition circuit compression volume from the volume delivered to the test lung. The compression factor was calculated by dividing the compression volume by the ventilating pressure. Five compliance settings were used on the TTL (0.1, 0.05, 0.03, 0.02, and 0.015 L/cm) to simulate different ventilating pressures. Pressure at the Y-connector, compressible volume, and volume delivered to the TTL were measured using a calibrated Timeter RT200 volume-pressure analyzer. Five measurements were made with each brand. A new circuit was used for each run with a disposable circuit, and a different circuit from the respiratory care department stock was used for each run with a nondisposable circuit. RESULTS: There were significant differences between the compression factors at different TTL compliance settings (p less than 0.001), and brands of circuits evaluated (p less than 0.001). There was a significant interaction effect for compression factors between TTL compliance setting and circuit brands (p less than 0.001). The compression factors for all disposable circuits were greater than the compression factors for the nondisposable circuits (p less than 0.05). CONCLUSIONS: There were differences in circuit compression factors as a function of the ventilating pressure and the brand of circuit. Although these differences are too small to be clinically important in many cases, they may be important during ventilation with low tidal volumes and high pressures.

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UNLABELLED: Due to increasing concern over potential cross-infection during cardiopulmonary resuscitation (CPR), a number of disposable resuscitators have become commercially available. The wearing of disposable medical gloves by persons performing CPR has also become commonplace. In this study, we evaluated the effects of hand size, use of disposable medical gloves, and number of hands used (one versus two) on the volumes delivered by five adult disposable resuscitators. METHOD: Persons familiar with bag-valve ventilation were recruited to participate in the study--eight with small hands, eight with medium hands, and eight with large hands. Ventilation was delivered to one side of a Vent-Aid training test lung (TTL), and volumes were measured with a BEAR VM-90. In random order, each participant ventilated the TTL with all combinations of one hand/two hands, gloves/no gloves, and each of the following resuscitators: Code Blue, Hospitak, Pulmanex, Mercury, and Ambu SPUR. The participants were instructed to ventilate the TTL as they would ventilate a patient. RESULTS: The mean =/- SD volumes (in liters) were small hands = 0.68 +/- 0.15, medium hands = 0.71 +/- 0.18, large hands = 0.81 +/- 0.19 (p=0.006); gloves = 0.73 +/- 0.19, no gloves = 0.73 +/- 0.18 (p=0.80); one hand = 0.62 +/- 0.12, two hands = 0.84 +/- 0.17 (p less than 0.0001); Code Blue = 0.79 +/- 0.14, Hospitak = 0.56 +/- 0.11, Pulmanex = 0.71 +/- 0.15, Mercury = 0.77 +/- 0.18, SPUR = 0.83 +/- 0.2 (p less than 0.0001). CONCLUSIONS: The use of gloves did not significantly affect volume delivery. Delivered volumes did increase significantly as hand size increased and as number of hands used to squeeze the bag increased, and observed differences in volume delivery between brands of resuscitators may be clinically important in some cases. This study emphasizes the importance of squeezing the resuscitator with two hands during bag-valve ventilation.

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