Annals of emergency medicine
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Since the implementation of a paramedic system in Seattle, yearly survival rates from out-of-hospital cardiac arrest due to ventricular fibrillation have averaged 25% without any significant increase over the years. Outcome for cardiac arrest associated with other rhythms has been poor: when asystole was the first rhythm recorded, only 1% of patients survived; when electromechanical dissociation was initially present, only 6% survived. ⋯ When outcome in 244 witnessed arrests was related to the times to beginning CPR and to initial defibrillation, mortality increased 3% each minute until CPR was begun and 4% a minute until the first shock was delivered. New strategies that minimize delays appear to have the greatest promise for improving survival after cardiac arrest.
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We assessed the ability of 64 emergency medical technicians (EMTs) to ventilate a resuscitation manikin with a bag valve mask and with a pocket face mask to determine if their skill levels met the American Heart Association standard of 12 ventilations per minute, each with a tidal volume of 800 mL or more. All ventilation attempts were made during ongoing chest compressions (60 per minute). A successful ventilation was defined as a tidal volume of 800 mL +/- 40 mL. ⋯ During a ten-minute extended skill assessment the EMTs averaged 9.6 ventilations per minute with the bag valve mask and 9.5 with the pocket face mask (NS). EMTs achieved initial success and maintained continued success better with the pocket face mask, but a reasonably high percentage (67%) met an objective standard when using the bag valve mask. We propose that objective standards be used to test the skills of EMTs for any ventilatory adjunct that they are permitted to use.
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The use of nitrous oxide as an anesthetic or analgesic agent frequently raises concerns about the possibility of post-inhalational diffusion hypoxemia. We undertook a study in 20 healthy volunteers to determine whether hypoxemia occurs after the self-administration by face mask of a 50:50 mixture of nitrous oxide and oxygen for 15 minutes, followed by breathing room air. Blood gases were measured through an in-dwelling arterial cannula before, during, and after inhalation of the mixture, at time O, five, ten, and 15 minutes, and then 30 seconds, 45 seconds, 2 1/2 minutes, five, and ten minutes following room air breathing. ⋯ No subject demonstrated arterial hypoxemia at any time before, during, or after self-administration of the gas mixture. In the ten subjects who self-administered the control gas there were no significant differences in the PaO2 values while they breathed either gas at any corresponding sampling time. We conclude that diffusion hypoxia is not seen in normal subjects following self-administration of a mixture of 50:50 nitrous oxide and oxygen.
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A 74-year-old man presented with bradycardia, diaphoresis, mental confusion, and slurred speech. He developed asystole and was managed successfully with temporary emergency transvenous pacing and support of ventilation and blood pressure. He later was found to have ingested approximately 1,500 mg diltiazem, apparently as the result of an error created by his blindness and chronic confusion.
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In the initial treatment of the hypovolemic trauma patient, commonly used crystalloids have little clinical benefit in the small volumes generally infused during transport. We evaluated the efficacy of a small-volume infusion of 7.5% NaCl in 6% Dextran 70 as a treatment modality for an otherwise lethal hemorrhage in swine. Sixty chronically instrumented swine were randomized into one of four treatment groups: 0.9% NaCl (NS, n = 15), 7.5% NaCl (HS, n = 15), 6% Dextran 70 (DEX, n = 16), and 7.5% NaCl in 6% Dextran 70 (HSD, n = 14). ⋯ The survival rate of the HSD group was significantly better than that of the NS group (P less than .001) and the HS group (P less than .01). The infusion of HSD increased mean arterial pressure, PCO2, and plasma bicarbonate to a significantly greater extent than NS alone (P less than .05). These results demonstrate that a small-volume infusion of the hypertonic sodium chloride/dextran solution is superior to equal volumes of a standard crystalloid in resuscitating animals from hemorrhagic shock.