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Biphasic extrathoracic pressure CPR: A human pilot study
RESEARCH FORUM ABSTRACTS
2 Biphasic Extrathoracic Pressure CPR: A Human Pilot Study HA Smithline, EP Rivers, MY Rady, HC Blake, RM Nowak/Baystate Medical Center and Henry Ford Hospital, Detroit, Michigan Study hypothesis: Alternating intrathoracic pressure by means of a chest cuirass can cause perfusion and ventilation equal to or better than standard CPR for human beings in cardiac arrest. Design: Nonrandomized, nonbfinded, crossover pilot study. Setting: Large urban emergency department. Subjects: Five adult normothermic, nontraumatic, out-of-hospital cardiac arrest patients unresponsive to standard ACLS. Method: Right atrial and aortic catheters were inserted for pressure measurcment and blood gas analysis while the patient was receiving standard CPR by a pneumatic compression device (ThumperrM). The Thumper TM was linen t-eplaced by a chest cuirass (Hayek Oscillator'M). Pressure and blood gas nlcasurements were then repeated. Rcsuhs: The coronary perfusion pressure increased from -1.2 _+8.6 mm Hg to (~.2 +__(~.9 nnn Hg for a mean change of 7.4 +- 3. I mm Hg (P = .006). The compression phase gradient increased l 0.0 _+21.9 mm Hg (P = .364). The vcnous to arterial Pco 2 gradient decreased 44.5 + 32.3 mm Hg (P = .070). "I-he oxygen cxuaction ratio increased 1.6 + 9.4% (P = .761). The mean arterial Po 2 and Pco 2 changed from 252 to 240 mm Hg (P = .836) and from 53 to (')(~(P = . 172) mm 11g, respectively. Conclusion: The ttayck Oscillator TM chest cuirass produccd a signi[icam improvcmcnl in tlnc coronary pcrfLtsion pressure. There was a trend [or improved systemic per[usion as indicatcd by an improved CPG and vcnous-to-alterial Pco 2 gradiem, ahhough this was nol supported by the tack of improvcnrelnt in the oxygen extraction ratio. The cuirass also adequately oxygenates and ventilates unassisted by positive pressure ventilation.
3 Stabilization of Rural Multiple Trauma Patients at Level III EDs Before Transfer to a Level I Trauma Center
KR Veenema,LE Rodewald/Departmentof EmergencyMedicine, Universityof Rochester School of Medicine, Strong Memorial Hospital, Rochester,New York Study ol)jective: To determine whether triage and stabilization of severely injured rural u-auma victims in outlying Level III emergency departments before transfer to Level I trauma centers have outcomes similar to national standards. Design: Retrospective review of all Level IIl ED trauma transfers and deaths over a four-year period (1988 to 1991). Setting: The two Level Ill EDs of a rural county in upstate New York and the urban Level I regional trauma center (45 minute, ground transport/ten minute, air transport). Participants: Sixty-three multiple trauma victims with a Trauma Triage Score of 11 or less. Forty-three were stabilized before transfer, and seven died in the Level lI1 ED. Thirteen were in trauma arrest at the scene and not analyzed further. Measurements and results: There were 57 blunt injuries and six penetrating injuries. Mean age was 34 years (range, 9 months to 97 years). The Revised Trauma Score on admission to the Level II1 ED was calculated for each of the 50 patients analyzed (mean, 5.41; range, 1.02 to 7.55), as was the ultimate Injury Severity Score (mean, 24; range, 1 to 66). With TRISS methodology, probabilities of survival (Ps) and death (Pd) were calculated. The results were compared with the Major Trauma Outcome Study (MTOS), the national outcome standard for trauma care, using current coefficients derived from Walker-Duncan regression analysis of MTOS data. A "quality of resuscitation" appraisal was done for each patient based on advanced trauma life support standards. Time of surgeon arrival (mean, 49 minutes; range, 0 minutes to three hours) and the time interval in the rural Level III ED
622
until transfer (mean, two hours ten minutes; range, 35 minutes to six hours 55 minutes) or death (mean, 61 minutes; range, 33 minutes to one hour 40 minutes) were measured. The predicted n u m b e r of deaths was 13.5, and the actual number was 12. Z statistic was .710. There were two unexpected survivors and three unexpected deaths. Both unexpected survivors (Ps, .32; Ps, .49) were characterized by early surgcon involvement (0 to 15 minutes), no flaws in the Level III resuscitation, and prompt transfer (one hour, 47 minutes and one hour 1 i minutes). In two unexpected deaths (Ps, .66; Ps, .55), there were multiple errors of omission and failure to recognize injury severity in addition to delayed surgeon involvement (35 minutes and 52 minutes). Both patients died before transfer. The other unexpected death (Ps, .52) occurred in the operating room at the Level I facility despite early surgeon involvement at the Level lII ED, only a minor resuscitation flaw, and i)rompt translcr (one hour 35 minutes). Conclusion: Triage and stabilization of severely injured rural trauma victims at Level Ill EDs before Level I transfer provide outcomes similar Io national standards. Establishment of rural Level 111 EDs oflering high-qualily resuscitative capability and innnediate surgical backup can be expected to improve further outcomes.
5~
Variability of Sensitivity as a Function of Fluid Volume in the "11' Sonographic Detection of Free Intraperitoneal Fluid SWBranney, REWolfe, EEMoore, N Albert, M Heinig, M Mestek/Departments of EmergencyMedicine, Surgery,and Radiology,DenverGeneral Hospital, Colorado
Study background: Uhrasound is commonly used s the detection of free intraperitoneal fluid after abdominal trauma. Previous studies have suggested that 100 to 300 mL of I]uid should be readily detcctablc. Objective: Although detectable, small volumes of intrapcritoncal Iluid are rarely seen with ultrasound. Setting: Municipal emergency department of a Level 1 trauma center. Participants: A convenience sample of attending physicians and residcnts in radiology, surgery, and emergency medicine. Emergency medicine attendings and residents underwent a two-hour inservice on recognizing fluid in Morrison's pouch followed by supervised examinations. Surgical attendings and residents underwent bedside teaching by experienced uhrasonographcrs Radiology residents underwent formal instruction by radiology attendings. A convenience sample of patients requiring evaluation with diagnostic peritoneal lavage (DPL) were entered into the study. The patients had to be hemodynamically stable, have no detectable intraperitoneal fluid by ultrasound before DPL, and have a negative DPL, both by aspiration and cell counts. Design: A prospective bhnded study. A Pie Medical Scanner Model 100 with a 3.5-MHz probe was used to identify Morrison's pouch. During the infusion of intraperttonea[ normal saline, the sonographer continuously scanned Morrison's pouch until fluid was first noted, at which point the volume infused was noted. The sonographer was blinded to the rate of fluid infusion as well as the volume infused. Results: A total of 100 patients were entered in the study between May 25, 1993, and August 16, 1993. The mean age was 33.1 years (range, 12 to 75 years), and the ratio of males to females was 4:1. ED attendings and residents performed 73% of the ultrasounds, with surgeons performing 20% and radiologists performing 7%. The mean volume detected was 626 mL, and the minimal amount detected was 225 mL. The overall sensitivity was 97% with 1 L of free intraperitoneal fluid. The volume at which 85% of the sonographers could detect flutd was 850 mL. Conclusion: Despite assertions that relatively small volumes of free intraperttoneal fluid may routinely be detected with ultrasound, high sensitivity is only attained at fluid volumes of more than 850 mL.
ANNALS OF EMERGENCYMEDIOINE 23:3 MARCH1994
2 Biphasic Extrathoracic Pressure CPR: A Human Pilot Study HA Smithline, EP Rivers, MY Rady, HC Blake, RM Nowak/Baystate Medical Center and Henry Ford Hospital, Detroit, Michigan Study hypothesis: Alternating intrathoracic pressure by means of a chest cuirass can cause perfusion and ventilation equal to or better than standard CPR for human beings in cardiac arrest. Design: Nonrandomized, nonbfinded, crossover pilot study. Setting: Large urban emergency department. Subjects: Five adult normothermic, nontraumatic, out-of-hospital cardiac arrest patients unresponsive to standard ACLS. Method: Right atrial and aortic catheters were inserted for pressure measurcment and blood gas analysis while the patient was receiving standard CPR by a pneumatic compression device (ThumperrM). The Thumper TM was linen t-eplaced by a chest cuirass (Hayek Oscillator'M). Pressure and blood gas nlcasurements were then repeated. Rcsuhs: The coronary perfusion pressure increased from -1.2 _+8.6 mm Hg to (~.2 +__(~.9 nnn Hg for a mean change of 7.4 +- 3. I mm Hg (P = .006). The compression phase gradient increased l 0.0 _+21.9 mm Hg (P = .364). The vcnous to arterial Pco 2 gradient decreased 44.5 + 32.3 mm Hg (P = .070). "I-he oxygen cxuaction ratio increased 1.6 + 9.4% (P = .761). The mean arterial Po 2 and Pco 2 changed from 252 to 240 mm Hg (P = .836) and from 53 to (')(~(P = . 172) mm 11g, respectively. Conclusion: The ttayck Oscillator TM chest cuirass produccd a signi[icam improvcmcnl in tlnc coronary pcrfLtsion pressure. There was a trend [or improved systemic per[usion as indicatcd by an improved CPG and vcnous-to-alterial Pco 2 gradiem, ahhough this was nol supported by the tack of improvcnrelnt in the oxygen extraction ratio. The cuirass also adequately oxygenates and ventilates unassisted by positive pressure ventilation.
3 Stabilization of Rural Multiple Trauma Patients at Level III EDs Before Transfer to a Level I Trauma Center
KR Veenema,LE Rodewald/Departmentof EmergencyMedicine, Universityof Rochester School of Medicine, Strong Memorial Hospital, Rochester,New York Study ol)jective: To determine whether triage and stabilization of severely injured rural u-auma victims in outlying Level III emergency departments before transfer to Level I trauma centers have outcomes similar to national standards. Design: Retrospective review of all Level IIl ED trauma transfers and deaths over a four-year period (1988 to 1991). Setting: The two Level Ill EDs of a rural county in upstate New York and the urban Level I regional trauma center (45 minute, ground transport/ten minute, air transport). Participants: Sixty-three multiple trauma victims with a Trauma Triage Score of 11 or less. Forty-three were stabilized before transfer, and seven died in the Level lI1 ED. Thirteen were in trauma arrest at the scene and not analyzed further. Measurements and results: There were 57 blunt injuries and six penetrating injuries. Mean age was 34 years (range, 9 months to 97 years). The Revised Trauma Score on admission to the Level II1 ED was calculated for each of the 50 patients analyzed (mean, 5.41; range, 1.02 to 7.55), as was the ultimate Injury Severity Score (mean, 24; range, 1 to 66). With TRISS methodology, probabilities of survival (Ps) and death (Pd) were calculated. The results were compared with the Major Trauma Outcome Study (MTOS), the national outcome standard for trauma care, using current coefficients derived from Walker-Duncan regression analysis of MTOS data. A "quality of resuscitation" appraisal was done for each patient based on advanced trauma life support standards. Time of surgeon arrival (mean, 49 minutes; range, 0 minutes to three hours) and the time interval in the rural Level III ED
622
until transfer (mean, two hours ten minutes; range, 35 minutes to six hours 55 minutes) or death (mean, 61 minutes; range, 33 minutes to one hour 40 minutes) were measured. The predicted n u m b e r of deaths was 13.5, and the actual number was 12. Z statistic was .710. There were two unexpected survivors and three unexpected deaths. Both unexpected survivors (Ps, .32; Ps, .49) were characterized by early surgcon involvement (0 to 15 minutes), no flaws in the Level III resuscitation, and prompt transfer (one hour, 47 minutes and one hour 1 i minutes). In two unexpected deaths (Ps, .66; Ps, .55), there were multiple errors of omission and failure to recognize injury severity in addition to delayed surgeon involvement (35 minutes and 52 minutes). Both patients died before transfer. The other unexpected death (Ps, .52) occurred in the operating room at the Level I facility despite early surgeon involvement at the Level lII ED, only a minor resuscitation flaw, and i)rompt translcr (one hour 35 minutes). Conclusion: Triage and stabilization of severely injured rural trauma victims at Level Ill EDs before Level I transfer provide outcomes similar Io national standards. Establishment of rural Level 111 EDs oflering high-qualily resuscitative capability and innnediate surgical backup can be expected to improve further outcomes.
5~
Variability of Sensitivity as a Function of Fluid Volume in the "11' Sonographic Detection of Free Intraperitoneal Fluid SWBranney, REWolfe, EEMoore, N Albert, M Heinig, M Mestek/Departments of EmergencyMedicine, Surgery,and Radiology,DenverGeneral Hospital, Colorado
Study background: Uhrasound is commonly used s the detection of free intraperitoneal fluid after abdominal trauma. Previous studies have suggested that 100 to 300 mL of I]uid should be readily detcctablc. Objective: Although detectable, small volumes of intrapcritoncal Iluid are rarely seen with ultrasound. Setting: Municipal emergency department of a Level 1 trauma center. Participants: A convenience sample of attending physicians and residcnts in radiology, surgery, and emergency medicine. Emergency medicine attendings and residents underwent a two-hour inservice on recognizing fluid in Morrison's pouch followed by supervised examinations. Surgical attendings and residents underwent bedside teaching by experienced uhrasonographcrs Radiology residents underwent formal instruction by radiology attendings. A convenience sample of patients requiring evaluation with diagnostic peritoneal lavage (DPL) were entered into the study. The patients had to be hemodynamically stable, have no detectable intraperitoneal fluid by ultrasound before DPL, and have a negative DPL, both by aspiration and cell counts. Design: A prospective bhnded study. A Pie Medical Scanner Model 100 with a 3.5-MHz probe was used to identify Morrison's pouch. During the infusion of intraperttonea[ normal saline, the sonographer continuously scanned Morrison's pouch until fluid was first noted, at which point the volume infused was noted. The sonographer was blinded to the rate of fluid infusion as well as the volume infused. Results: A total of 100 patients were entered in the study between May 25, 1993, and August 16, 1993. The mean age was 33.1 years (range, 12 to 75 years), and the ratio of males to females was 4:1. ED attendings and residents performed 73% of the ultrasounds, with surgeons performing 20% and radiologists performing 7%. The mean volume detected was 626 mL, and the minimal amount detected was 225 mL. The overall sensitivity was 97% with 1 L of free intraperitoneal fluid. The volume at which 85% of the sonographers could detect flutd was 850 mL. Conclusion: Despite assertions that relatively small volumes of free intraperttoneal fluid may routinely be detected with ultrasound, high sensitivity is only attained at fluid volumes of more than 850 mL.
ANNALS OF EMERGENCYMEDIOINE 23:3 MARCH1994