Prehospital Application Research Articles

Reliability and validity of prehospital case finding for depression and cognitive impairment.

To evaluate the test-retest reliability, the concurrent criterion validity, and the construct validity of prehospital, emergency medical service (EMS) case finding for depression and cognitive impairment in older adults. Cross-sectional study. Prehospital EMS system and hospital emergency department. EMS providers and community-dwelling older adult (aged > or =60) patients. Case finding instruments for depression (Patient Health Questionnaire-2; PHQ-2) and cognitive impairment (Six-Item Screener). The reliability and validity of these instruments. Moderate test-retest reliability was found for prehospital application of the PHQ-2 (kappa=0.50) and Six-Item Screener (kappa=0.52), fair concurrent criterion validity for depression (kappa=0.36), and slight to fair concurrent criterion validity for cognitive impairment (kappa=0.11-0.23). Construct validity was demonstrated using the Multitrait-Multimethod Matrix. Moderate test-retest reliability and construct validity were demonstrated for prehospital case finding by EMS providers for cognitive impairment and depression using these instruments. Slight to fair concurrent criterion validity was found, a result that methodological limitations could explain. These findings provide additional support for the concept of using EMS providers to detect older adults at risk for these conditions. Further work is needed to confirm the validity and effectiveness of prehospital screening before such programs are implemented.

Heliox in acute severe asthma in the A&E setting: a review

Heliox (HeO2) is a mixture of helium and oxygen, often mixed in 80:20 or 70:30 ratios for use in medicine and clinical investigations. Heliox has been available for use in the UK since 2002 and is supplied as Heliox 21 (21% oxygen and 79% helium) by BOC Gases for medical use in asthma, croup, chronic obstructive pulmonary disease and other medical procedures. Heliox use in asthma exacerbations remains largely experimental owing to the limited number of randomized controlled trials. This review aims to critically analyse the efficiency of Heliox use in acute asthma exacerbations in the Accident and Emergency (A&E) setting, evaluate its effectiveness as a medium for nebulization, and assess potential benefits to clinical practice. Prehospital application will also be discussed in moderate-severe asthma exacerbations. It is envisaged that the factors relating to Heliox use in asthma are focused to provide an additional therapy to the current choice of therapies for prehospital clinicians.

A standardised pre-hospital electronic patient care system

This paper describes the design, development and testing of a pre-hospital documentation and patient monitoring application called iRevive. The application utilises a sensor gateway and data mediator to enable semantic interoperability with a wide variety of medical devices and applications. Initial test results indicate that complete and consistent pre-hospital Electronic Medical Records (EMR) can be semantically exchanged with two heterogeneous, in-hospital IT applications.

Is helmet CPAP first line pre-hospital treatment of presumed severe acute pulmonary edema?

Non-invasive continuous positive airway pressure (CPAP) is effective in reducing intubation rate and mortality of patient with acute cardiogenic pulmonary edema (ACPE). We report our experience on pre-hospital application of CPAP by helmet as an adjunct to medical therapy or as a stand alone procedure in patient with presumed ACPE. In pre-hospital treatment of 62 patients with presumed ACPE, CPAP was added to standard medical treatment while in another 59 patients, CPAP was used as a sole therapy. Helmet CPAP was feasible in all patients. No patient required pre-hospital intubation. In both groups, CPAP significantly improved oxygenation (SpO(2) went from 79 +/- 12 to 97 +/- 3% and from 81 +/- 13 to 98 +/- 3%), reduced respiratory rate (from 26 +/- 4 to 21 +/- 3 bpm and from 30 +/- 9 to 22 +/- 8 bpm) and improved hemodynamics, with a more pronounced decrease in blood pressure in the group with medical treatment than in the one without it. In the two cohorts, four and five patients were, respectively, intubated in Emergency Department and 11 and 9 eventually died. Helmet CPAP is feasible, efficient and safe in pre-hospital treatment of presumed ACPE. A significant improvement of physiological variables was observed also in the group treated with CPAP in the absence of a drug therapy. We propose helmet CPAP as first line pre-hospital treatment of presumed severe ACPE.

Basic physiology of hyperbaric oxygen in brain

Oxygen is the proverbial 'double-edged sword' in that it is a necessity for life in moderation and toxic and detrimental to life in excess. This too is the dilemma in hyperbaric oxygen (HBO) treatment in cerebral ischemic–anoxic insults such as stroke, head injury, near drowning, asphyxia, cardiac arrest, etc., i.e. the brain at risk, where regions of ischemia are beside regions of marked hyperemia. The natural heterogeneity of normal brain tissue oxygenation compounds the problem with different microvascular brain regions living at various levels of oxygenation from 0 to arterial PO2 as an added complication. The application of HBO, whether normobaric or hyperbaric, will result in brain tissue oxygenation ranging from normoxic to highly hyperoxic with the latter possibly exacerbating the injury sustained. On this basis, the application of multiple therapeutic interventions may be considered, for example, HBO in combination with free radical scavengers or inhibitors of free radical generating enzymes. Despite these difficulties in moderating oxygen delivery to treat cerebral ischemic–anoxic insults, overwhelming preclinical evidence indicates that HBO administered during or within 2 hours post-insult effectively attenuates the severity of brain damage sustained. The primary disconnection between pre-clinical and clinical efficacy of HBO then appears to be the time of application. Clinically, HBO therapy is applied at the earliest 6 hours post-insult but usually between 12 hours or longer post-insult. Pre-hospital application of HBO may be required for clear-cut demonstration of clinical efficacy.

Noncontact Vital Sign Monitoring System for Isolation Unit (Casualty Care System)

For measuring the vital signs of casualties inside an isolation unit, we developed a noncontact vital sign monitoring system using a microwave radar. The system was tested on eight healthy volunteers ranging in age from 30 to 48 years. The heart and respiratory rates derived by the microwave radar correlated with the heart and respiratory rates determined by electrocardiogram and respiratory sensor (r = 0.98, p < 0.0001 for heart rate; r = 0.84, p < 0.01 for respiratory rate). The exhaled CO and CO2, as a measure of trauma injury, were measured using an exhaled gas analyzer. The CO and CO2 concentrations were found to average 3.8 +/- 4.3 ppm and 2.9 +/- 0.4%, respectively. The expired air temperature and body temperature, as indicators of hemorrhagic hypothermia, averaged 31.8 +/- 1.7 degrees C and 36.2 +/- 0.4 degrees C, respectively. The results show that our system is promising for future prehospital application in determining casualty conditions for fluid infusions by the Casualty Care System intravenous lines.

Prehospital Management of Rapid Atrial Fibrillation: Recommendations for Treatment Protocols

The present study was completed to establish an epidemiological database defining prehospital rapid atrial fibrillation (RAF) and interventions given such patients in the hope of developing recommendations for further treatment protocols. On review of 4,749 paramedic run reports from a low-volume urban emergency medical services (EMS) system, 33 persons (0.69%) presented with RAF. Data collected included vital signs/ventricular rate, patient age, ambulance field times, patient chief complaint, prehospital interventions, efficacy of interventions, additional cardiac rhythms, iatrogenic complications, and patient past medical history. Neither intravenous (IV) diltiazem or electrical cardioversion were used within the 12-month period of this study. Symptomatic/supportive care consisting of observation (72.73%) and interventions (27.27%) with nitroglycerine, furosemide, aspirin, morphine, and/or IV fluid bolus therapy accounted for all prehospital treatment. Paramedics documented improvement in 100% of patients. No cases occurred in which RAF resulted in severe hemodynamic instability. No inappropriate use, point estimate (PE) [(0)/(33) (0.00% to 10.60%)], or unmet need, PE [(0)/(4,716) (0.00% to 0.08%)] of care was noted. The data presented in this study suggest that given similar EMS system characteristics, prehospital RAF is an infrequently encountered, predominantly hemodynamically stable cardiac arrhythmia, readily treatable with symptomatic/supportive care, and cautious observation. The prehospital application of adult advanced cardiac life support guidelines utilizing IV diltiazem and electrical cardioversion for the treatment of RAF may be unnecessary.

Transtelephonic defibrillation

This study was undertaken to assess the safety and reliability of a device for transtelephonic defibrillation. The transtelephonic system consists of a patient unit and a base station. The patient unit contains a monitor-defibrillator, electrode pads, microphone, microprocessor, and DC defibrillator. The base station comprises a control panel, computer, and ECG display. Fifteen patients who were treated in our emergency department for cardiac arrest were placed on patient units that activated our base station in a remote location within the ED. Thirteen patients were treated for ventricular fibrillation, and two patients were treated for ventricular tachycardia. Thirty-one shocks were delivered transtelephonically. In all cases, voice and ECG transmission were established without difficulty. We conclude that this system represents a safe and reliable method for the treatment of ventricular fibrillation, and we advocate additional use to study the prehospital applications of transtelephonic defibrillation.