Prehospital experience with defibrillation of coarse ventricular fibrillation: a ten-year review.

Early defibrillation of patients with coarse ventricular fibrillation has been implicated as a predictor of survival in prehospital cardiac arrest. A retrospective study of our experience with prehospital defibrillation was conducted to define the relationship between rapid delivery of first countershock and survival, determine whether a relationship exists between the number of countershocks delivered and the save rate, and assist clinicians with general guidelines for termination of advanced life support efforts in the presence of ventricular fibrillation refractory to multiple defibrillation attempts. During the ten-year study period, adult, nontraumatic, nonpoisoned, witnessed arrests with an initial rhythm of coarse ventricular fibrillation were reviewed. Of 1,497 patients, 25% survived, 13% were paramedic-witnessed (PW) arrests, and 87% were non-paramedic-witnessed (NPW) arrests. The mean PW shock time, defined as time from arrest to first shock, was 1.6 +/- 3.7 minutes with a save rate of 37%. The mean NPW shock time was 10.2 +/- 5.1 minutes with a save rate of 23% (P less than or equal to .001). Thirty-two percent of PW arrests were converted to a spontaneous rhythm with pulses after the first countershock compared with 9% of NPW arrests (P less than or equal to .001). There was a dramatic decrease in PW arrests obtaining a perfusing rhythm after the first countershock attempt with each minute delay in electrical countershock up to three minutes; a plateau effect was evident after three minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Status of trauma center designation.

1) In 1986 20 states are designating trauma centers. 2) ACS guidelines appear to be the accepted standard. 3) Almost all of the states providing designation retain the power of final designation but allow individual hospitals to initiate the process. 4) Designation is usually based on actual capability and frequently requires a site visit team in which surgeons and emergency medicine physicians play a prominent role. 5) Designation appears to be for a finite period of time but half of the states do not provide for de-designation. 6) A national mandate is necessary for timely and uniform implementation of trauma center designation.

Decision making in prehospital sudden cardiac arrest.

Many studies of prehospital resuscitation report on selected populations. We examined a series of 445 unselected nontraumatic cardiac arrests. Emergency cardiac care (ECC) was not initiated in 126 (28%). ECC was begun in 319 (78%), but was terminated in 132 (33%). Ninety-four (21%) were admitted to the hospital with palpable pulses and organized rhythm (successful resuscitation/save rate for patients presenting in ventricular fibrillation was 50%/25%. Multivariate regression analysis was used to identify the relative importance of significant variables in predicting survival, and the analysis identified the presence of ventricular fibrillation, short paramedic response times, and short paramedic treatment times.

Comparison of clinical CPR studies in Milwaukee and elsewhere in the United States.

As we mark the 25th anniversary of the clinical application of closed-chest cardiopulmonary resuscitation (SCPR), it is time to look back and analyze the progress we have made in the resuscitation of sudden death syndrome. Recent studies of SCPR's effectiveness have yielded mixed results, in comparison to early studies that were universally favorable. The continued toll of neurologic injury following SCPR resuscitation, and reinforcement of the importance of defibrillation in resuscitation, stimulate us to find improved forms of SCPR and improved methods of resuscitation delivery in emergency medical systems.

Traumatic cardiac arrest: scope of paramedic services.

The challenge of the 1960s to ambulance care provision was the stimulus for the emergence of prehospital advanced life support (ALS) being provided by paramedic personnel. While services for cardiac disease have been accepted, paramedic activities for the trauma victim continue to be a concern for many trauma surgeons. The capability and success rate of treatment, and the time spent at the scene and during transport to the hospital have raised questions about the overall need for paramedic services. Our study period was from January 1, 1981, to December 31, 1982, and it covered 95 clinically dead trauma victims who were first seen and subsequently treated by paramedics working in a medically controlled emergency medical services system. Endotracheal intubation was successful in 81 of the patients (85%). Esophageal obturator airway use was viewed as unsuccessful intubation. Intravenous (IV) access utilizing 16-gauge angiocaths was placed successfully by a peripheral or jugular vein in 70 patients (74%). Thirty-three patients averaged 860 mL volume infusion (30 to 3,000 mL). Average scene time was 22 minutes. Scene time of patients with unsuccessful IV and endotracheal intubation was 14 minutes (P = .07). Fourteen patients (14.7%) were admitted to the operating room or intensive care unit. Only three of the study group (3.2%) survived.

Effects of high infusion pressure and large-bore tubing on intravenous flow rates.

An in vitro study was conducted to determine the maximum flow rates that can be obtained with commercially available intravenous (IV) catheters, when infusion pressure and IV tubing size are modified. Standard tubing (3.2 mm ID) and two sizes of experimental large-bore tubing (5.0 mm and 6.4 mm ID) were tested with tap water and diluted packed cells (hematocrit 45) at 600 mm Hg, 300 mm Hg, and gravity flow infusion pressure. The maximum flow rate obtained was 3,158 ml/min for tap water and 3,000 ml/min for diluted packed cells. The increases in flow rates from gravity to 300 mm Hg and from gravity to 600 mm Hg are significant (P less than 0.05) and provide up to 197% and 341% increases, respectively, for all catheter/tubing combinations tested. Large-bore tubing is most effective when used in conjunction with large-bore catheters. For the 8.5 French catheter, a change from standard (3.2 mm ID) to large-bore (6.4 mm ID) tubing resulted in a statistically significant (P less than 0.05) increase in flow rate of more than 200% regardless of infusion pressure.

Pre-hospital IAC-CPR versus standard CPR: paramedic resuscitation of cardiac arrests.

Recent studies evaluating interposed abdominal compression cardiopulmonary resuscitation (IAC-CPR) have demonstrated a significant increase in cardiac output, mean arterial pressure, and cerebral perfusion, as compared with standard CPR. A clinical evaluation of IAC-CPR effectiveness on resuscitation outcome has not been reported. A prospective randomized study comparing IAC-CRP with standard CPR for resuscitation of prehospital cardiopulmonary arrest was undertaken using the Milwaukee County Paramedic System. The patients were randomized following endotracheal intubation into IAC-CPR and standard CPR groups. Since October 1983, 291 patients have qualified for the study group. Of these, 146 patients had standard CPR, and 45 (31%) were successfully resuscitated. Of the 145 patients treated with IAC-CPR, 40 (28%) were successfully resuscitated. Chi-square analysis reveals no significant difference between these groups. To determine whether abdominal compression increases regurgitation, the frequency of emesis before and after intubation was analyzed. No significant difference was found between the IAC-CPR and standard CPR groups. Thus, IAC-CPR applied by paramedics in the field to patients following intubation does not improve cardiac resuscitation rates.

Effect of circumferential pneumatic compression devices on digital flow.

We reviewed the effects of circumferential pneumatic compression suits (CPCS) when applied to normal and ischemic limbs without prior application of prehospital orthopedic traction devices beneath the garment. The digital arterial toe pressures of 11 normal and six claudicating limbs were measured with the trouser applied and the limbs pressurized to 40, 60, 80, and 100 mm Hg. In addition, normal limbs had the Hare traction device and the Sager splint applied prior to application of the trouser and retesting of the digital arterial flow. We conclude that CPCS prevents flow into the limbs, and this may potentiate the development of compartment syndromes in the previously traumatized or ischemic limbs. Normal limbs with traction devices already applied may be at a higher risk for compartment syndromes, and we suggest that patients with fractured limbs who are in need of CPCS not have the traction device applied.

Bystander CPR in prehospital coarse ventricular fibrillation.

Prehospital bystander cardiopulmonary resuscitation (CPR) was studied to determine if it affected the outcome of defibrillation. Four hundred twenty-one consecutive witnessed cardiopulmonary arrests presenting with the initial rhythm of coarse ventricular fibrillation treated by the Milwaukee County Paramedic System from January 1980 to June 1982 were analyzed. Pediatric, trauma, and poisoning patients and those receiving intravenous or endotracheal medications before defibrillation (58) were excluded. Immediate professional bystander CPR (physician, nurse, EMT) and citizen bystander CPR were compared to a control group receiving no bystander CPR until arrival of EMS personnel. A successful defibrillation occurred if defibrillation prior to administration of medication produced an effective cardiac rhythm with pulses. Eighty-eight of the 363 remaining patients (24%) converted with initial defibrillations. While the group receiving professional bystander CPR had a higher successful defibrillation rate than did the no-CPR group (35% vs 22%, P less than .04), citizen bystander CPR and no-CPR groups had similar successful defibrillation rates (24% vs 22%, no significant difference). One hundred eighty-six of the 363 patients (51%) were transported to a hospital with a rhythm and a pulse (a successful resuscitation). Ninety-seven of the 363 patients (27%) were discharged alive from the hospital (a save). Patients who were converted successfully using initial "quick-look" defibrillations were far more likely to be successfully resuscitated (79/88 [90%] vs 107/275 [39%], P greater than .0001) and to be discharged alive from the hospital (54/88 [61%] vs 43/275 [16%], P greater than .0001) than were those who required further advanced cardiac life support techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

The precordial thump.

The American Heart Association (AHA) currently recommends the precordial thump as the initial maneuver in treatment of ventricular tachycardia (VT) and monitored ventricular fibrillation (VF). These recommendations are based largely on anecdotal reports of successful "thump-version" of asystole, VF, and VT. The Milwaukee County Paramedic System follows the AHA guidelines in the treatment of VT and VF. The precordial thump is included in the advanced cardiac life support (ACLS) paramedic training program, and has been used in our approach to the pulseless, nonbreathing patient. During an eight-month period, 50 pulseless, nonbreathing patients received precordial thumps during ACLS resuscitative attempts. Twenty-seven patients who developed monitored VT and 23 patients with monitored VF were thumped. Three of 27 patients (11%) with VT were thumped into a supraventricular rhythm, 12 of 27 patients (44%) remained in VT, and 12 of 27 patients were thumped from VT into more malignant rhythms: three, into asystole; eight, into VF; and one, into an idioventricular/electromechanical dissociation rhythm. A total of 23 patients were thumped without effect. Subsequently, using countershock and medications, 12 of these 23 patients were successfully resuscitated. In the prehospital setting the precordial thump is usually not beneficial, and may be detrimental. Thus its use as the initial maneuver in treating the cardiac arrest patient with VT or VF in this setting cannot be supported. The presence of acidosis and hypoxia may explain why prehospital precordial thump responses differ from those seen in the hospital environment.

Recommended helmet removal techniques in a cervical spine injured patient.

Helmet removal techniques in the absence of C-spine injuries have been developed and promulgated. Utilizing a cadaver model, these techniques were demonstrated to adversely affect pre-existing C-spine injury. Removal of helmets with cast cutters is recommended.

Interposed abdominal compression CPR versus standard CPR in prehospital cardiopulmonary arrest: preliminary results.

Recent studies evaluating interposed abdominal compression cardiopulmonary resuscitation (IAC-CPR) have demonstrated a significant increase in cardiac output, mean arterial pressure, and cerebral perfusion compared with standard CPR. A clinical evaluation of IAC-CPR effectiveness on resuscitation outcome has not been reported. A prospective, randomized study comparing IAC-CPR with standard CPR for resuscitation of prehospital cardiopulmonary arrest was developed utilizing the Milwaukee County Paramedic System. When the paramedics arrive, standard CPR is initiated or continued, and countershocks are delivered when appropriate. The patients are randomized into IAC-CPR and standard CPR groups immediately following endotracheal intubation. Abdominal compression force is standardized to 100 mm Hg +/- 20 mm Hg by using a simple airfilled bladder and gauge to monitor each compression. Resuscitations are conducted according to standard advanced cardiac life support guidelines through continuous radio-telemetry contact with a base physician. Since October 1983, 140 patients have qualified for the study group. Seventy patients had standard CPR and 30% (21/70) were admitted to the emergency department with a rhythm and pulse, as were 34% (24/70) of the patients treated with IAC-CPR. The difference between study groups was not significant. To determine if abdominal compression increases regurgitation, the frequency of emesis before and after intubation was analyzed. No significant difference was found between the IAC-CPR and standard CPR groups.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized comparison study of bretylium tosylate and lidocaine in resuscitation of patients from out-of-hospital ventricular fibrillation in a paramedic system.

A prospective, randomized study using either bretylium tosylate (BT) or lidocaine (L) as the first-line antiarrhythmic for patients in refractory ventricular fibrillation was conducted using the Milwaukee County Paramedic System. If the patient did not respond to the initial American Heart Association protocol, BT (10 to 30 mg/kg total) or L (2 to 3 mg/kg total) was given randomly as the first antiarrhythmic. If the patient failed to convert, the alternate antiarrhythmic was given. In the L group, 81% (39/48) of the patients obtained an organized electrical rhythm and 56% (27/48) converted to a rhythm with a pulse. The resuscitation rate (admission to an emergency department with pulse) was 23% (11/48), and the save rate was 10.4% (5/48). In the BT group, 74% (32/43) obtained an organized electrical rhythm, 35% (15/43) were converted, 23% (10/43) were resuscitated, and 5% (2/43) were saved. The only significant difference in outcome was that L converted patients better than did BT (P less than .05). Of the 24 patients known to be on digitalis preparations prior to arrest, 41% (5/12) in the L group were resuscitated and 16% (2/12) were resuscitated in the BT group. Data were analyzed for witnessed arrest outcome and for patients given multiple antiarrhythmics.

Experimental cervical spine injury model: evaluation of airway management and splinting techniques.

We evaluated airway management maneuvers and the effects of cervical splinting on a model of an injured spinal column. X-ray films of a fresh cadaver verified a normal cervical spine. C5-C6 instability was created surgically and documented radiologically with flexion and extension maneuvers. Basic and advanced airway techniques were performed and were documented radiologically. The procedures were then repeated using different types of splinting. Chin lift, jaw thrust, esophageal obturator airway (EOA), and endotracheal intubation can cause extension, widening, and/or anterior subluxation. A two-piece, semirigid soft cervical collar may minimize flexion but not extension of the spine. With the Velcro in back, soft collars minimize flexion; with Velcro in front, they minimize extension. Standard nonsurgical airway management techniques appear to aggravate preexisting injuries. The soft collar and semirigid collar do little to prevent movement, and their presence may serve only as a warning to physicians that a neck injury may be present.

Resuscitation time in ventricular fibrillation--a prognostic indicator.

Length of resuscitation in prehospital ventricular fibrillation patients was studied to define its relationship to survival. Five hundred sixty-five patients presenting with the initial rhythm of ventricular fibrillation to the Milwaukee County Paramedic System between January 1978 and April 1982 were resuscitated successfully. Pediatric patients and patients with trauma, poisoning, and drowning were excluded. Of the 565 resuscitated patients, 262 (46%) were discharged alive and 303 (54%) died during hospitalization. For all 565 patients the resuscitation time and times from arrival of paramedics until the first sustained pulse were plotted against survival to define a curve. The curve demonstrated rapidly declining survival rates for resuscitation time up to 20 minutes; thereafter, survival declined more gradually with respect to resuscitation time. The mean resuscitation time for those eventually discharged alive was 12.6 minutes, which was statistically shorter (P less than .0001) than the mean resuscitation time of 23.9 minutes for those who eventually died. The overall survival curve of witnessed arrest patients was not statistically different from that of unwitnessed patients. The survival curve of those patients receiving bystander cardiopulmonary resuscitation (CPR) was similar to the curve of those who received no CPR. We conclude that resuscitation time is a heretofore undefined significant predictor of survival of resuscitated prehospital ventricular fibrillation patients.

Out-of-hospital pulmonary edema: diagnosis and treatment.

Sixty-two patients diagnosed by paramedics as having acute cardiac pulmonary edema out of the hospital were studied. The paramedic prehospital diagnosis as confirmed by an emergency physician, chest film, and hospital admission evaluation was correct in 55 of 62 patients (89%). In the group with acute cardiac pulmonary edema, 64% demonstrated cardiac dysrhythmias, including cardiac arrest, prior to the patient's hospitalization. Therapy administered by the paramedics was beneficial in that most patients had improved on arrival at the hospital. Six of the 10 patients (60%) sustaining cardiac arrest were successfully resuscitated. Acute cardiac pulmonary edema occurring outside the hospital is commonly associated with significant complications, including life-threatening arrhythmias. Well-trained paramedics are capable of quickly diagnosing and treating acute cardiac pulmonary edema outside the hospital setting.

The effect of a paramedic system on mortality of major open intra-abdominal vascular trauma.

In a 12-year period (1970-1981), there were 112 patients operated on with major open intra-abdominal vascular trauma (MOIVT). These were any penetrating injuries to the aorta, inferior vena cava, portal vein, or their primary branches. Sixty-four patients were treated without benefit of paramedics. Only four of 43 patients who had emergency department blood pressures of 60 mm Hg or greater upon entry died (9.3%), whereas 18 of 21 (85.7%) patients with blood pressures of less than 60 mm Hg died (p less than 0.0001). Forty-eight of the 112 patients have been treated by paramedics during the past 4 years. Entry level blood pressures are those first recorded by the paramedics in the field. The mortality in those with blood pressures of 60 mm Hg or greater remained essentially unchanged. However, 11 of 22 patients with blood pressures of less than 60 mm Hg survived compared to three of 21 (p less than 0.025). Over the past 12 years, the community's homicide rate has been stable (71/yr), but the case incidence of MOIVT has risen from an average of 8/yr to 12/yr during the paramedic years. The average annual aggravated assault rate increased from 796 to 1,119. It is believed the improvement in the salvage rate is due to early intervention by trained paramedics functioning within a trauma care system.

Use of calcium in prehospital cardiac arrest.

All records of patients presenting to the Milwaukee County Paramedic System for the period of January 1 to December 31, 1980 were reviewed retrospectively. One hundred seventy-nine patients initially presented in asystole, and 116 patients initially presented in electromechanical dissociation (EMD). All patients with trauma and poisoning were excluded. The in-field successful resuscitation rates for asystole were 8/105 (8%) in the calcium group versus 8/24 (33%) in the no-calcium group (P less than .002); for EMD they were 10/63 (16%) in the calcium group versus 8/18 (44%) in the no-calcium group (P less than .02). A successful resuscitation is defined as the conveyance of a patient to the emergency department with a pulse and cardiac rhythm. There were no significant differences between the calcium and no-calcium groups in both the asystole and EMD patients. The use of calcium in the prehospital setting in the currently recommended dosage for cardiac arrest with initial arrest rhythms of asystole and EMD is highly suspect.

Rapid fluid resuscitation with central venous catheters.

We attempted to determine whether central venous catheters are effective for rapid fluid administration in moderately to severely hypovolemic patients. Comparative maximum flow rates with water and blood products were tabulated for various central and peripheral catheters. The USCI 8 and 9 French introducers (USCI Cardiology and Radiology Division, CR Bard, Inc, Ellerica, MA) had the fastest flow rates of all catheters tested (P less than .05). The best peripheral catheter, IV extension tubing cut to 12-inch length, had slightly less flow than did the introducers (P less than .05). The Deseret Subclavian Jugular Catheter (Deseret Co, Sandy, UT) had by far the slowest measured flow rates. Several parameters were evaluated that alter flow rates regardless of catheter size, including a pressure infusion cuff, packed red blood cells diluted with normal saline, and a Fenwal blood warmer (Fenwal Laboratories, Division of Travenol Laboratories, Inc, Deerfield, IL). Central venous catheters can be effective adjuncts for rapid fluid administration.