Mortality from isolated civilian penetrating extremity injury.

BACKGROUND: Although studies have ascertained that ten percent of soldiers killed in battle bleed to death from extremity wounds, little data exists on exsanguination and mortality from extremity injuries in civilian trauma. This study examined the treatment course and outcomes of civilian patients who appear to have exsanguinated from isolated penetrating extremity injuries. METHODS: Five and 1/2 years' data (Aug 1994 to Dec 1999) were reviewed from two Level I trauma centers that receive 95% of trauma patients in metropolitan Houston, TX. Records (hospital trauma registries, emergency medical system (EMS) and medical examiner data) were reviewed on all patients with isolated extremity injuries who arrived dead at the trauma center or underwent cardiopulmonary resuscitation (CPR) or emergency center thoracotomy (ECT). RESULTS: Fourteen patients meeting inclusion criteria were identified from over 75,000 trauma emergency center (EC) visits. Average age was 31 years and 93% were males. Gunshot wounds accounted for 50% of the injuries. The exsanguinating wound was in the lower extremity in 10/14 (71%) patients and proximal to the elbow or knee in 12/14 (86%). Ten (71%) had both a major artery and vein injured; one had only a venous injury. Prehospital hemorrhage control was primarily by gauze dressings. Twelve (86%) had "signs of life" in the field, but none had a discernable blood pressure or pulse upon arrival at the EC. Prehospital intravenous access was not obtained in 10 patients (71%). Nine patients underwent ECT, and nine were initially resuscitated (eight with ECT and one with CPR). Those undergoing operative repair received an average of 26 +/- 14 units of packed red blood cells. All patients died, 93% succumbing within 12 hours. CONCLUSION: Although rare, death from isolated extremity injuries does occur in the civilian population. The majority of injuries that lead to immediate death are proximal injuries of the lower extremities. The cause of death in this series appears to have been exsanguination, although definitive etiology cannot be discerned. Intravenous access was not obtainable in the majority of patients. Eight patients (57%) had bleeding from a site that anatomically might have been amenable to tourniquet control. Patients presenting to the EC without any detectable blood pressure and who received either CPR or EC thoracotomy all died.

Hypothermia after cardiac arrest: feasibility and safety of an external cooling protocol.

BACKGROUND: No proven neuroprotective treatment exists for ischemic brain injury after cardiac arrest. Mild-to-moderate induced hypothermia (MIH) is effective in animal models. METHODS AND RESULTS: A safety and feasibility trial was designed to evaluate mild-to-moderate induced hypothermia by use of external cooling blankets after cardiac arrest. Inclusion criteria were return of spontaneous circulation within 60 minutes of advanced cardiac life support, hypothermia initiated within 90 minutes, persistent coma, and lack of acute myocardial infarction or unstable dysrhythmia. Hypothermia to 33 degrees C was maintained for 24 hours followed by passive rewarming. Nine patients were prospectively enrolled. Mean time from advanced cardiac life support to return of spontaneous circulation was 11 minutes (range 3 to 30); advanced cardiac life support to initiation of hypothermia was 78 minutes (range 40 to 109); achieving 33 degrees C took 301 minutes (range 90 to 690). Three patients completely recovered, and 1 had partial neurological recovery. One patient developed unstable cardiac dysrhythmia. No other unexpected complications occurred. CONCLUSIONS: Mild-to-moderate induced hypothermia after cardiac arrest is feasible and safe. However, external cooling is slow and imprecise. Efforts to speed the start of cooling and to improve the cooling process are needed.

Effect of application of force to self-adhesive defibrillator pads on transthoracic electrical impedance and countershock success.

STUDY OBJECTIVE: To examine the effect of the application of force to self-adhesive defibrillator pads on transthoracic electrical impedance and countershock success. METHODS: A prospective, randomized, controlled pilot study was carried out in an experimental animal laboratory, involving 32 mixed-breed swine weighing 36.5 to 55.7 kg each. Ventricular fibrillation (VF) was induced, and the animals were randomly allocated to 1 of 4 groups, with 8 animals per group. Animals in groups I and II remained in VF for 30 seconds; those in groups III and IV remained in VF for 5 minutes. At the end of the VF period, up to 3 countershocks were given. In groups I and III, countershocks were delivered through the self-adhesive defibrillator pads alone; in groups II and IV, they were delivered through the defibrillator pads with 25 lb of applied force. Any animal without return of spontaneous circulation after 3 countershocks was given epinephrine after 1 minute of CPR, followed by 1 additional minute of CPR and 1 additional countershock if required. RESULTS: The main measurements included baseline and countershock transthoracic impedance, cumulative countershock success rate, and 30-minute survival rate. Application of 25 lb of force to the defibrillator pads significantly decreased transthoracic impedance, compared with baseline values (group II, 15. 1% decrease; group IV, 16.1% decrease). The first-shock success rate was higher when force was applied during the countershock (87.5% versus 50% for groups II and I, respectively; 62.5% and 37.5% for groups IV and III, respectively). In the animals who experienced 5 minutes of VF, there were greater rates of success after the second, third, and fourth countershocks when force was applied (group IV) than when no force was applied (group III). Groups I and II (VF for 30 seconds) demonstrated 100% survival at 30 minutes. Group IV had a higher 30-minute survival rate (3/8 animals) than did group III (1/8). However, the rates of countershock success and 30-minute survival were not statistically different among the groups. CONCLUSION: Application of force to self-adhesive defibrillator pads decreases transthoracic impedance during countershock. This effect may contribute to improving the countershock success rate.

Adenosine for the prehospital treatment of paroxysmal supraventricular tachycardia.

STUDY OBJECTIVE: To determine the efficacy and feasibility of adenosine for the treatment of paroxysmal supraventricular tachycardia (PSVT) in the prehospital setting. DESIGN: Prospective case series. SETTING: Large, urban, advanced life support emergency medical services system. PARTICIPANTS: One hundred twenty-nine adult patients with PSVT, as identified by paramedic personnel. Pregnant patients and those taking carbamazepine or dipyridamole were excluded. INTERVENTIONS: Dose of 12 mg adenosine by rapid i.v. push followed by a 5-mL saline flush and a repeat dose of 12 mg adenosine i.v. push if the patient's rhythm remained unchanged. MEASUREMENTS AND MAIN RESULTS: Six-second lead II rhythm strips and vital signs were documented before and 2 minutes after the administration of adenosine. Demographic information, past medical history, medications, number of adenosine doses given, and complications were recorded by the paramedic on a case-report form. One hundred six of 129 (82%) of the case-report forms included the rhythm strips from before and after adenosine administration. Actual initial rhythms were determined by a consensus panel. The initial rhythms were PSVT in 79% (84 of 106) of patients, atrial fibrillation in 12% (13 of 106), sinus tachycardia in 5% (five of 106), atrial flutter in 2% (two of 106), and ventricular tachycardia in 2% (two of 106). Eighty-five percent (71 of 84) of patients in PSVT were successfully converted to sinus rhythms; four (5.6%) of these patients required a second 12-mg dose. One patient in atrial fibrillation spontaneously converted to normal sinus rhythm and one patient in ventricular tachycardia converted after adenosine. All other patients not initially in PSVT remained in their initial rhythm. Complications occurred in 12 of 129 patients and included chest pain (five), flushing (three), shortness of breath (two), nausea (one), anxiety (one), dizziness (one), headache (one), and seizure (one). All complications were transient and required no treatment. Prior history of PSVT was the only variable associated with a higher rate of conversion (P = .029). CONCLUSION: Paramedics are able to accurately identify PSVT using a single lead. Adenosine is safe and effective treatment for PSVT in the prehospital setting. This series is the largest prehospital study of adenosine use to date.