The purpose of this study was to assess subjectively the performance of the pharyngeo-tracheal lumen (PTL) airway in a multi-agency, prehospital emergency medical service (EMS) environment.

Data were recorded by the EMS provider on 1,647 adult patients (age range 16–92 years) in whom a PTL or endotracheal (ET) airway insertion was attempted. Analysis of variance and Fisher's Exact tests were used for statistical analysis.

There were no significant differences between the PTL and ET groups, either in patient demographics or in rates of successful ventilation with either airway overall or in trauma-related versus non-trauma-related cases, male versus female patients, or volunteer versus paid EMS providers. Basic life support (BLS) providers were able to ventilate successfully with the PTL as frequently as were ALS providers using the ET tube.

The PTL appears to be a useful primary airway for BLS providers and for ALS providers who are called upon infrequently to manage an airway acutely. The PTL also may be used as an alternate airway for ALS providers when tracheal intubation cannot be accomplished. Further study is needed to define the effectiveness of the PTL in the management of patients with trauma-related injuries.

This study sought to determine the lifesaving potentials of modern resuscitation medicine as applied to a catastrophic disaster situation. Previous articles reported the preliminary results (I), and methodology (II) of a structured, retrospective interview study of the 1988 earthquake in Armenia. The present article (III) reports and discusses the definitive findings, formulates conclusions, and puts forth recommendations for future responses to catastrophic disasters anywhere in the world.

Observations include: 1) The lack of adequate construction materials and procedures in the Armenian region contributed significantly to injury and loss of life; 2) The uninjured, lay population together with medical teams including physicians in Armenia were capable of rapid response (within two hours); 3) Due to a lack of Advanced Trauma Life Support (ATLS) training for medical teams and of basic first-aid training of the lay public, and scarcity of supplies and equipment for extrication of casualties, they were unable to do much at the scene. As a result, an undetermined number of severely injured earthquake victims in Armenia died slowly without the benefit of appropriate and feasible resuscitation attempts.

1) Widespread adoption of seismic-resistant building codes for regions of high seismic risk; 2) The lay public living in these regions should be trained in life-supporting first-aid (LSFA) and basic rescue techniques; 3) Community-wide emergency medical services (EMS) systems should be developed world-wide (tai-lored to the emergency needs of each region) with ATLS capability for field resuscitation; 4) Such systems be prepared to extend coverage to mass casualties; 5) National disaster medical system (NDMS) plans should provide integration of existing trauma-EMS systems into regional systems linked with advanced (heavy) rescue (public works, fire, police); and 6) New techniques and devices for victim extrication should be developed to enable rapid extrication of earthquake casualties within 24 hours.

To determine the clinical efficacy, patient volume, and program costs that justify pediatric intraosseous (IO) infusion as a routine skill for the treatment of patients with cardiac arrest in a prehospital system.

A decision analytic model was constructed to include patient outcomes and costs to society. Critical variables for the analysis were: 1) time to vascular access; 2) success of vascular access; 3) clinical efficacy (i.e., the percentage of lives saved by early vascular access); 4) number of patients requiring IO annually; and 5) the cost of an IO program. Program costs included training and equipment expenses. Sensitivity analysis, which repeatedly evaluates the model using different values for the critical variables, identified those values at which IO would be cost-effective.

With an estimated 80% success rate for IO access within five minutes, the cost-per-life-saved would be [US] $161,000. This cost-effectiveness ratio assumed annual program expenses of $2,000 and one patient per year needing IO. The cost-effectiveness ratio also required a clinical efficacy of 2% for vascular access. To prove that the clinical efficacy of vascular access is in fact 2%, epidemiologic studies would require a sample of nearly 9,000 patients.

This analysis suggests IO probably is cost-effective given a clinical efficacy above 2%. While the true efficacy may be below this value, clinical studies are unlikely to have sufficient size to prove it. Therefore, emergency medical services (EMS) medical directors must make the decision to utilize IO based on their own beliefs about its clinical efficacy. Further, it must be considered in the context of other prehospital programs which may be more cost-effective. Such analyses permit establishment of rational priorities to rank programs in prehospital systems.

Centralized dispatch data can provide useful information regarding the impact of major air medical system changes in a regional emergency medical services (EMS) system.

Prospective evaluation of helicopter dispatch data from a centralized EMS dispatch agency. During the study period, four alterations in the total number of helicopters available to the system occurred (1,2,3,2,3). Statistical analysis consisted of Chi-Square with Yates' correction and comparison of sample proportions with p<.05 considered significant.

A total of 667 helicopter dispatches occurred during the 20-month study period from April 1989 through November 1990.

Changes in dispatch patterns could result either from increased availability or alterations in the dispatchers' “threshold” for use based upon a perceived lessening of the need to save a “scarce” resource. Had the second possibility played a significant role, the rate of cancellation by ground personnel after arrival at the scene would be expected to have increased. Since this did not occur, it is likely that the increased use actually was a result of increased availability. In systems that dispatch helicopters prior to arrival of ground personnel, this method of evaluation may provide a useful model for analyzing the impact of major system alterations.

Airway management is the most critical and potentially life-saving intervention performed by emergency medical service (EMS) providers. Invasive airway management often is required in non-cardiac-arrest patients who are combative or otherwise uncooperative. The success of prehospital invasive airway management in this patient population was evaluated.

A retrospective review was undertaken of the records of all such patients requiring endotracheal intubation over a three-year period (1987–1989). The study population included 278 patients enrolled by five advanced life support (ALS) units serving a suburban population of 425,000. Field trip sheets were reviewed for diagnosis, intubation method and success, number of intubation attempts, provider experience, reasons for unsuccessful intubations, and complications.

A total of 394 invasive airway management attempts were performed on 278 patients. The overall successful intubation rate was 75% (41 % orotracheal, 52% nasotracheal, 7% other or unknown). The most common diagnoses were COPD and pulmonary edema (30%) and trauma (24%). Experienced providers were successful on the first attempt in 57% of cases compared to 50% by inexperienced providers (p=.24). Multiple intubation attempts were required in 33% of the patients. There was no statistically significant difference in success rates between the orotracheal and nasotracheal methods (p=.51). The most common reason for unsuccessful intubation was altered level of consciousness. Complications occurred with 7% of successful attempts and in 18% of unsuccessful attempts (p<.001). Forty-six percent of the patients who were not intubated successfully in the field and required intubation in the emergency department (ED) received a neuromuscular blocking agent prior to successful intubation.

Prehospital providers can intubate a high but improvable proportion of non-cardiac-arrested patients by both the orotracheal and nasotracheal routes. The use of pharmacologic adjuncts to facilitate the prehospital intubation of selected, non-cardiac-arrested patients is a promising adjunct that needs further evaluation.

Gas-powered resuscitators (ventilators) designed to be used primarily for resuscitation should be basic and simple to use. They offer many advantages over manual methods of ventilation during in-hospital cardiopulmonary resuscitation. Portable ventilators intended for critical care transport require additional, more sophisticated features such as: adjustable pressure limiting valves, air-mixing, airway pressure gauge, independent tidal volume and rate controls, and a Positive End-Expiratory Pressure (PEEP) valve. The performance of six gas-powered resuscitators/portable ventilators (TransPAC, Oxylog, Ambu Matic, ERA 2000, Uni-Vent, and MARS) was evaluated.

The accuracy of volumes delivered to a test lung at three different compliance and resistance settings, was assessed for each ventilator prior to clinical evaluation during cardio-pulmonary resuscitation (CPR) and patient transport.

In each circumstance, measured tidal volumes and levels of minute ventilation decreased as resistance was increased and compliance reduced. Much of this loss of measured tidal volume occurred through inspiratory pressure relief valves that tended to start leaking at pressures below the preset level. Increasing levels of back-pressure resulted in further reductions in tidal volume when the ventilators were tested using the air-mix mode (available on three of the devices). In general, each resuscitator functioned well when used during CPR within the hospital.

Each resuscitator tested failed to deliver the preset volumes and this must be considered during their use. Inspiratory pressure relief valves for all but one of the ventilators tested would not permit the delivery of adequate levels of ventilation in patients with low pulmonary compliance and/or high airway resistance.

Casualty Collection Points (CCPs) are sites predesignated by county officials for the congregation, triage, austere medical treatment, holding, and evacuation of casualties following a major disaster. A CCP (and the simulation) is made up of a series of discrete, interrelated steps that collectively result in medical care being provided to a casualty.

A series of computer simulations was run comparing differences in personnel, supplies, and evacuation configuration for a jurisdiction that has plans in place to establish a CCP, and for one that does not. Each simulation was for 650 earthquake-related casualties.

Generally, it was found that: 1) mortality appears to be related directly to performance of triage of casualties and to where they are directed for care. The least injured did not need to be treated at a CCP; 2) survival is related directly to arrival time, mix of medical staff, and the ability to form “care teams” on-site; 3) the sudden, massive arrival of casualties will result in a “snowball” mortality effect if staff numbers are low or do not include the proper mix of training to form care teams well before the peak arrival time of casualties; 4) holding ambulances until they are filled completely before evacuation may increase mortality; 5) during the first four hours, more lives may be saved by using transportation assets to move medical staff and supplies to a CCP, if large numbers of casualties are expected to congregate there. Generally, the local jurisdiction must be prepared to mobilize a significant number of medical staff and supplies to a predesignated CCP within 4–6 hours after an event.

The simulation produced useful information. In particular, local disaster response planners need to develop rapid response methods to ensure that the best combination of medical staff are available early to care for casualties.

Emergency cardiopulmonary resuscitation (CPR) instruction via telephone (ETCPR) is cost-effective compared to prehospital, emergency medical technician (EMT)/paramedic treatment alone of witnessed, ventricular fibrillation (VF) in adult patients.

A total of 118 patients, age >18 years, with prehospital, witnessed ventricular fibrillation were studied. Patient data were extracted from hospital records, monitor-defibrillator recordings, paramedic reports, dispatching records, and telephone interviews with bystanders. No ETCPR was available during this period. The costs of ETCPR implementation were estimated retrospectively. Marginal cost of the paramedic service attributable to treatment of VF was calculated from fire department records. Years-of-life saved were estimated from age, gender, and race matched norms.

Of the 53 patients receiving bystander CPR (BCPR), 14 (26%) survived to hospital discharge versus 4/65 patients (6%) lacking BCPR, These groups did not differ significantly (p>.05) in age, EMS response times, or time from collapse to defibrillation. The mean time interval from collapse to CPR was significantly less for patients with BCPR (1.8 min) than for patients without BCPR (7.1 min). Had all patients received BCPR and survived at the rate of 0.26, 13 additional patients would have survived to hospital discharge. The cost per year-of-life saved by the EMS system with ETCPR would have been [US]$2,834 versus $4,881 without ETCPR. The cost per additional year-of-life saved by ETCPR was estimated to be $560 in patients experiencing out-of-hospital ventricular fibrillation.

The use of ETCPR instruction of callers by 9-1-1 dispatchers potentially is a cost-effective addition to a two-tier, EMS system for treatment of prehospital ventricular fibrillation.