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Biomedical subjects

K R Stults

Publications and source records attributed to K R Stults.

12 recordsLinked to original sources
PubMed1988

A new rhythm library for testing automatic external defibrillators: performance of three devices.

A library of arrhythmias obtained from patients with cardiac arrest was developed. Such a data base will permit both in vitro testing of the rhythm analysis system of automatic external defibrillators before clinical field trials are conducted and comparison of devices. Defibrillators equipped with voice/electrocardiographic tape recorders and used in the prehospital defibrillation programs in Iowa and King County, Washington provided the rhythm source. From these recordings, segments of ventricular fibrillation with minimal artifact and a duration of greater than or equal to 6 s were selected. Segments of ventricular fibrillation (n = 102) were categorized by average peak amplitude as fine (1 to less than 3 mm), medium (3 to less than 7 mm), coarse (7 to less than 12 mm) and extra coarse (greater than or equal to 12 mm), and transcribed onto high fidelity videocassette tapes. Nonventricular fibrillation cardiac arrest rhythms (n = 144), which included wide complex idioventricular rhythms, ventricular and supraventricular tachycardias, asystole and artifact, were also transcribed. Automatic external defibrillators developed by three manufacturers reached a treat (shock) decision on 88 to 93% of the ventricular fibrillation rhythms and on 5 to 10% of the nonventricular fibrillation rhythms. The latter decisions were defined as false positive, though for many rapid nonventricular fibrillation rhythms, countershock may be the appropriate treatment response. There were no statistically significant differences among the three devices in the shock/no shock decisions. A variety of ventricular fibrillation arrhythmias and terminology to express the preclinical performance of automatic external defibrillators are defined. Three commercially available automatic external defibrillators appear to successfully identify ventricular fibrillation and nonventricular fibrillation rhythms.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1987

Self-adhesive monitor/defibrillation pads improve prehospital defibrillation success.

We compared self-adhesive, dual-function monitor/defibrillation electrode pads to standard chest monitoring leads and hand-held electrode paddles in the management of prehospital ventricular fibrillation in a single urban paramedic service. Shocks were delivered more quickly following paramedic arrival with self-adhesive pads than with hand-held paddles (1.6 vs 2.5 min; P less than .001). Ventricular fibrillation was terminated more frequently when shocks were delivered using the self-adhesive pads (55 of 58 patients, 95%) than when shocks were delivered using hand-held paddles (49 of 69 patients, 71%; P less than .005). Initial shocks delivered with self-adhesive pads were especially effective, converting 40 of 58 (69%) patients to an organized rhythm on the first or second shock; this was true of only 24 of 69 (35%) patients shocked with hand-held paddles (P less than .001). Patient survival to hospital admission improved when self-adhesive pads were used: 30 of the 58 (52%) patients shocked with self-adhesive pads achieved hospital admission, while only 21 of 69 patients (30%; P less than .025) survived to admission when hand-held paddles were used. In addition, electrical artifact that interfered with accurate rhythm interpretation was far more prevalent when standard monitoring electrodes were used, including artifact that resulted in inappropriate shock delivery (23% of patients monitored with standard electrodes vs 3% of patients monitored with self-adhesive pads; P less than .005). Self-adhesive monitor/defibrillation pads are superior to standard monitoring leads and hand-held electrode paddles in the management of prehospital ventricular fibrillation.

Adhesives↗
PubMed1986

Refibrillation managed by EMT-Ds: incidence and outcome without paramedic back-up.

Some patients converted from ventricular fibrillation to organized rhythms by defibrillation-trained ambulance technicians (EMT-Ds) will refibrillate before hospital arrival. The authors analyzed 271 cases of ventricular fibrillation managed by EMT-Ds working without paramedic back-up. Of 111 patients initially converted to organized rhythms, 19 (17%) refibrillated, 11 (58%) of whom were reconverted to perfusing rhythms, including nine of 11 (82%) who had spontaneous pulses prior to refibrillation. Among patients initially converted to organized rhythms, hospital admission rates were lower for patients who refibrillated than for patients who did not (53% versus 76%, P = NS), although discharge rates were virtually identical (37% and 35%, respectively). Scene-to-hospital transport times were not predictively associated with either the frequency of refibrillation or patient outcome. Defibrillation-trained EMTs can effectively manage refibrillation with additional shocks and are not at a significant disadvantage when paramedic back-up is not available.

Allied Health Personnel↗
PubMed1986

Efficacy of an automated external defibrillator in the management of out-of-hospital cardiac arrest: validation of the diagnostic algorithm and initial clinical experience in a rural environment.

Automatic external defibrillators (AEDs) may have advantages over manual defibrillation in managing prehospital cardiac arrest, particularly in rural communities. We conducted a two-part evaluation of a commercially available AED. We first established the diagnostic accuracy of the AED's rhythm recognition algorithm by challenging it with 205 cardiac arrest rhythms previously recorded from actual patients in the field. The AED demonstrated 100% specificity and 92% sensitivity for ventricular fibrillation (VF) in this nonclinical setting. We then compared the clinical efficacy of AEDs in 18 small communities (study group) with that of manual defibrillation in 18 additional communities (control group) of similar size. Ambulance technicians using manual defibrillators correctly diagnosed VF more frequently than the AEDs (98% vs 83%; p less than .025). Specificity for VF was similar in the two groups (100% for AEDs vs 94% for technicians; p greater than .10). AEDs were able to deliver shocks more quickly than was possible with the manual defibrillators (1.56 vs 2.77 min; p less than .001). The ability of the AEDs to terminate VF was excellent, converting VF in 28 of 29 (97%) patients to some other rhythm compared with only 37 of 53 (70%) patients in the control group (p less than .01). Hospital admission and discharge rates were similar for the two groups. Ten of the 35 (29%) patients managed with AEDs achieved admission and six (17%) were ultimately discharged. In the control group 17 of 53 (33%) patients with VF were admitted and seven (13%) were discharged (p less than .75). AEDs are an effective alternative to manual defibrillation in small communities.

Diagnosis, Computer-Assisted↗
PubMed1986

EMT-defibrillation in rural America.

Physician assistants who work in community medicine must be aware of the need for, and limitations of, prehospital emergency care systems. In rural communities, effective emergency cardiac care systems lag behind those of urban areas: establishing and maintaining a rural paramedic-level ambulance service is expensive, and continued competency must be shown in complex skills even when the volume of emergency calls is low. Basic-level ambulance technicians can be trained in 16 hours to recognize and defibrillate patients in ventricular fibrillation, however, and automated external defibrillators that require minimal training to use may simplify effective, advanced cardiac care. Defibrillation programs require strong medical control and well-designed quality assurance mechanisms. Medical control is ultimately the responsibility of the physician-medical director, but in many small communities day-to-day tasks of medical control and quality assurance are assumed by PAs.

Allied Health Personnel↗
PubMed1986

Special considerations for defibrillation performed by emergency medical technicians in small communities.

Defibrillation by minimally trained ambulance technicians can significantly improve survival after out-of-hospital cardiac arrest in communities of all sizes. However, special consideration must be given to the development of such services in small communities, chiefly because of problems associated with the low volume of true emergency calls. Communities considering implementing programs by which defibrillation is performed by the emergency medical technician (EMT-D) must first evaluate their ambulance response times and, if inadequate, alter their system of ambulance response. After implementation of such a program, a permanent, formal skill maintenance program must be established. Defibrillation protocols must allow for the fact that many patients will refibrillate after successful conversion, yet no advanced care beyond the defibrillator will generally be available. Finally, every community instituting an EMT-D program must maintain a system of monitoring EMT performance and patient outcome that documents acceptable survival-to-discharge rates as well as the safety of the program. For smaller communities a regional or statewide evaluation system may be preferable to individual community programs.

Allied Health Personnel↗
PubMed1984

Prehospital defibrillation performed by emergency medical technicians in rural communities.

Survival after out-of-hospital cardiac arrest is poor in communities served only by basic ambulance services, but conventional advanced prehospital care is not an option for most rural communities. Ambulance technicians in 18 small communities (average population, 10,400) were trained to recognize and defibrillate ventricular fibrillation. Neither endotracheal intubation nor medication was used. Twelve additional communities of similar size where such early defibrillation was not attempted provided control data. In the communities where early defibrillation was available, 12 of 64 patients (19 per cent) who were found in ventricular fibrillation were resuscitated and discharged alive from the hospital; this was true of only 1 of 31 such patients (3 per cent) in the control communities, where only basic life support was available (P less than 0.05). Ten (83 per cent) of the long-term survivors received electrical shocks administered solely by the technicians. Early defibrillation by minimally trained ambulance technicians is an effective approach to emergency cardiac care in rural communities.

Adolescent↗