Concepts and application of prehospital ventilation.

Airway management and optimal ventilation are crucial aspects of managing out-of-hospital medical emergencies. The goals in these situations are controlled ventilation and optimized inspiratory time, expiratory time, and airflow. Numerous techniques and devices are available to deliver oxygen-enriched air to patients during resuscitation. The bag-valve-mask (BVM) is one of the most common devices used to provide ventilation, although the American Heart Association ranks BVM devices lower in preference than other ventilation adjuncts, such as emergency and transport ventilators (ETVs) and pocket masks. The clearly documented limitations of BVM ventilation and its widespread use in the United States underscore the need to improve ventilation practices during care provided by emergency medical services (EMS) personnel. As part of that improvement, ETVs clearly have a role in the prehospital setting. These devices should be available on every ambulance, and the ability to use ETVs should be part of each EMS provider's skill set. Furthermore, all patients requiring emergency ventilation must be adequately monitored, including continuous monitoring of end-tidal carbon dioxide concentrations. As with any other skill, ventilation requires attention during initial training, continuing education and skill reinforcement, and quality review.

Management of difficult airways in the field.

Establishing an airway is a critical first step in emergency management of comatose patients and those who have suffered head trauma, cardiac arrest, or respiratory failure. The use of succinylcholine, a paralytic, to assist with intubation is a safe and effective way to help establish an airway under difficult circumstances, in the prehospital setting. It requires excellent intubation skills, a thorough knowledge of the indications and contraindications of its use, and similar knowledge of any other medications employed. Succinylcholine-assisted intubation should never be implemented without close physician monitoring. Therefore, under the auspices of strong medical control, it is an effective way to establish adequate oxygenation and to control ventilation in some of the most critical patients encountered in the field. Additionally, because physical examination alone is not dependable for ensuring proper endotracheal tube placement, an objective confirmatory device such as an end-tidal carbon dioxide detector should be used.

Prehospital use of succinylcholine: a 20-year review.

OBJECTIVE: To determine the safety and efficacy of succinylcholine, as an adjunct to endotracheal intubation, administered by paramedics trained in its use. METHODS: Retrospective review of 1,657 consecutive patients, aged 16 years or older, receiving prehospital succinylcholine administered by paramedics. In this community of 175,000 people, trained paramedics intubated both medical and trauma patients with the assistance of succinylcholine. Main outcomes measured were success of intubations, complications of the procedure and/or the drug, and use of alternative methods of airway management. RESULTS: Paramedics successfully intubated 95.5% (1,582) of all patients receiving succinylcholine, 94% (1,045) of trauma patients, and 98% (538) of medical patients. They were unable to intubate 4.5% (74) of the patients. All of these were successfully managed by alternative methods. Unrecognized esophageal intubation occurred in six (0.3%) patients. The addition of capnography and a tube aspiration device, in 1990, decreased the incidence of esophageal intubations. CONCLUSION: Paramedics trained to use succinylcholine, to assist the process of endotracheal intubation, can safely intubate a high percentage of patients.

End-tidal carbon dioxide and outcome of out-of-hospital cardiac arrest.

BACKGROUND: Survival after cardiac arrest occurring outside the hospital averages less than 3 percent. Unfortunately, the outcome of prolonged resuscitative attempts cannot be predicted. End-tidal carbon dioxide levels reflect cardiac output during cardiopulmonary resuscitation. We prospectively determined whether death could be predicted by monitoring end-tidal carbon dioxide during resuscitation after cardiac arrest. METHODS: We performed a prospective observational study in 150 consecutive victims of cardiac arrest outside the hospital who had electrical activity but no pulse. The patients were intubated and evaluated by mainstream end-tidal carbon dioxide monitoring. Our hypothesis was that an end-tidal carbon dioxide level of 10 mm Hg or less after 20 minutes of standard advanced cardiac life support would predict death. RESULTS: There was no difference in the mean age or initial end-tidal carbon dioxide level between patients who survived to hospital admission (survivors) and those who did not (nonsurvivors). After 20 minutes of advanced cardiac life support, end-tidal carbon dioxide (+/-SD) averaged 4.4+/-2.9 mm Hg in nonsurvivors and 32.8+/-7.4 mm Hg in survivors (P< 0.001). A 20-minute end-tidal carbon dioxide value of 10 mm Hg or less successfully discriminated between the 35 patients who survived to hospital admission and the 115 nonsurvivors. When a 20-minute end-tidal carbon dioxide value of 10 mm Hg or less was used as a screening test to predict death, the sensitivity, specificity, positive predictive value, and negative predictive value were all 100 percent. CONCLUSIONS: An end-tidal carbon dioxide level of 10 mm Hg or less measured 20 minutes after the initiation of advanced cardiac life support accurately predicts death in patients with cardiac arrest associated with electrical activity but no pulse. Cardiopulmonary resuscitation may reasonably be terminated in such patients.

Use of end-tidal carbon dioxide to predict outcome in prehospital cardiac arrest.

STUDY OBJECTIVE: End-tidal CO2 (ETCO2) measurement can be used to predict death in prehospital cardiac arrest patients with pulseless electrical activity (PEA). DESIGN: A prospective, observational study. SETTING: An urban and rural emergency medical services system in northwestern Washington state. PARTICIPANTS: Ninety consecutive victims of prehospital cardiac arrest with PEA. INTERVENTIONS: Patients were intubated in the field and treated using standard advanced cardiac life support protocols with online medical control. In addition, all patients were evaluated using mainstream ETCO2 monitoring. In this study, a hypothetical decision was made to cease resuscitative efforts based on an ETCO2 level of 10 mm Hg or less after 20 minutes of advanced cardiac life support. RESULTS: The study included 90 patients (61 were men) with a mean age of 67.6 +/- 13.6 years (range, 27 to 95 years). The initial ETCO2 averaged 11.7 +/- 6.6 mm Hg in nonsurvivors (range, 5 to 50 mm Hg) and 10.9 +/- 4.9 mm Hg in survivors (range, 5 to 24 mm Hg) (P > .672 [NS]). After 20 minutes of advanced cardiac life support, ETCO2 averaged 3.9 +/- 2.8 mm Hg (range, 0 to 12 mm Hg) in patients in whom the theoretical decision was made to cease field resuscitation. In contrast, survivors' ETCO2, just before restoration of circulation, averaged 31 +/- 5.3 mm Hg (range, 16 to 35 mm Hg) (P < .0001). Using an ETCO2 of 10 mm Hg or less as a theoretical threshold to predict death in the field successfully discriminated between the 16 survivors to hospital admission (those that achieved return of spontaneous circulation) and 75 prehospital deaths. Of the 16 survivors to hospital admission, 9 died in the hospital, and 7 were discharged from the hospital alive. In 13 of the 16 survivors, the first evidence of return of spontaneous circulation, before a palpable pulse or blood pressure, was a rising ETCO2. The logistic-regression parameters for the model are 4.4391 + ETCO2*-0.3624 (P < .0001). Sensitivity was 97.3%; specificity 100%; positive predictive value 100%; and negative predictive value 88.9%. CONCLUSION: This study suggests that a low ETCO2 (10 mm Hg or less) can be used to predict irreversible death in patients with pulseless electrical activity undergoing prehospital advanced cardiac life support. If future studies validate this model, use of ETCO2 may allow for triage decisions in the field.

Clinical evaluation of Epi-Lock--a semiocclusive dressing.

Epi-Lock, a new semiocclusive, semipermeable dressing, was evaluated against standard therapy for three common emergency department wounds: partial thickness burns, deep abrasions, and selected lacerations. Comparison was made of quality of wound healing; rate of wound healing; level of pain experienced, postdressing, by the patient; and ease of use by the staff. One hundred patients in each group (standard treatment versus Epi-Lock) included approximately 40 burns, 35 abrasions, and 25 lacerations in each subgroup. The results of this study showed a statistically significant difference (P less than .01) in all categories for Epi-Lock versus standard therapy. Epi-Lock may be a useful new dressing for all types of wounds presenting to the emergency department.

Clinical evaluation of the antishock trouser: retrospective analysis of five years of experience.

A retrospective study of five years of experience in using pneumatic antishock trousers was undertaken to provide data for analysis of clinical response and complications associated with use of the suit. Of 1,120 patients who received pneumatic antishock trousers, 821 (73.3%) survived more than 24 hours, and their response and clinical course were analyzed. Response was not uniform: most exhibited blood pressure response, and some showed changes in only pulse rate or evidence of improved tissue perfusion. Different responses were noted for different shock etiologies. Of all the potential complications theoretically possible, a prevalence of only 4% for ischemic skin changes (none requiring grafting) and 0.97% for renal perfusion failure were noted. The pneumatic antishock trouser is thought to be beneficial and safe.

Clinical evaluation of the antishock trouser: prospective study of low-pressure inflation.

We designed a prospective study to address the question of the adequacy of low-pressure (20 to 30 mm Hg) inflation of pneumatic anti-shock trousers when in use on hypotensive patients in the prehospital and emergency department settings. For an eight-month period, all patients who were candidates for pneumatic trousers received a two-stage inflation process. Of 120 patients who received trousers, 91 survived more than 24 hours, and their response to low-pressure inflation was analyzed. The majority (70%) did not respond at low pressure. Those patients who did respond were characterized by a higher initial systolic pressure (P less than .05), indicating that their degree of shock was relatively mild. In responding patients, the response varied, affirming the importance of full clinical assessment. Gauges showing intrasuit pressure are not necessary to evaluate patient condition.

Clinical evaluation of a new device for the treatment of tension pneumothorax.

The two accepted major methods for decompression of a pneumothorax are needle aspiration in the second intercostal space and large bore chest tube insertion in the midaxillary line, sixth, seventh or eight intercostal space. Both of these devices have drawbacks in the emergency management of a tension pneumothorax. Relating to size, case of insertion, volume of air aspirated and cumbersomeness of associated equipment. This evaluation of its effectiveness is both in the prehospital phase and in the Emergency Department by studying 40 patients, 55% of which were prehospital. Sixty per cent were placed by EMT-Paramedic personnel. All of those patients that survived their multiple trauma long enough to allow x-rays to be made, had partial to total re-expansion of the pneumothorax. Of those patients undergoing autopsy or surgical exploration no indication could be identified of pulmonary injury secondary to the insertion of the device. The only complications were: intercostal artery laceration and a minor laceration of the dome of the diaphram. In summary this study of 40 patients demonstrates the effectiveness of the use of a device for the management of tension pneumothorax, both prehospital and in-hospital by physician and EMT-Paramedic personnel.

An automatic cardiac resuscitator for emergency treatment of cardiac arrest.

A new, portable, automatic resuscitator seeks respiratory signals and electrocardiogram of a victim in cardiac arrest through an intrapharyngeal sensor and a lingual-epigastric skin pathway. The resuscitator then assesses the status of the patient and delivers either an electric impulse to defibrillate or a pacing pulse, as indicated by an algorithmic logic circuit gated by respiratory rate and ECG. Field testing the device on 21 patients in ventricular fibrillation resulted in 35 successful conversions to sinus rhythm and 1 long-term survivor. Pacing was accomplished in two humans. Such a device has great potential for saving lives by eliminating crucial time now spent waiting for skilled help and equipment to arrive.

The MAST suit in the treatment of cardiogenic shock.

Based on initial success using the medical antishock trouser (MAST) suit in treating 150 patients in traumatic, hypovolemic shock in the city of Bellingham and Whatcom County, Washington, at St. Luke's Hospital, the indications for its use have been expanded to include certain types of cardiogenic shock. The rationale was based on the frequent inability to differentiate hypo-, hyper-, and normovolemia in patients in cardiogenic shock and the need for a safe, reversible fluid challenge to differentiate these conditions. Changes in the condition of 14 patients in cardiogenic shock after application of the MAST suit were evaluated. Six patients responded with improved cardiac output and blood pressure. Four had no significant change in their condition and four became worse. In all patients whose condition was unchanged or worsened, the fluid challenge was reversed by deflating the suit. Based on these preliminary findings, it would seem that extended indications exist for using the MAST suit.

PSRO: issues in health care policy.

Enactment of the law regarding Professional Standards Review Organizations (PSROs) represents a major shift in health care policy in the United States. PSRO is an experiment in developing a national quality assurance system. It raises issues of quality versus cost control, professional versus public accountability, and confidentiality. These issues must be examined critically by social workers.

Conversion of paroxysmal atrial tachycardia by facial immersion in ice water.

Based on the concept of the classic diving reflex, which produced bradycardia, a technique for treating uncomplicated, but symptomatic, paroxysmal atrial tachycardia was developed. This technique consists of facial immersion for 15 to 30 seconds in water at 10 C (50 F). Of ten patients 9 (90%) achieved rapid conversion without complications. This technique may be especially useful for those patients resistant to more conventional methods of inducing conversion of paroxysmal atrial tachycardia.