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At least 19 recordsLinked to original sources
PubMed1977

Precision calibration of patient care equipment as failure predictor.

Reliability of patient care equipment could be enhanced if failures could be predicted and repairs made on a routine instead of emergency basis. The paper describes the efforts of the Biomedical Engineering Department at Brookdale Hospital Medical Center to use changes in accuracy of selected parameters as failure predictor. Monthly precision tests of ECG rate computers, strip chart recorders and waveform analysis of defibrillator discharges were used in this experiment. For defibrillators and strip chart records failures could clearly be predicted but the results for ECG rate computers are still inconclusive.

Biomedical Engineering↗
PubMed1975

Application of powder failure testing equipment in assessing effect on glidants on flowability of cohesive pharmaceutical powders.

Powder failure testing equipment was used successfully to study the effect of glidants on the flowability of two cohesive pharmaceutical powders, lactose and calcium hydrogen phosphate, using the flow factor as the flowability parameter. Fine silica, magnesium stearate, and purified talc were investigated as glidants; for each host powder-glidant mixture, an optimum concentration of glidant was observed beyond which no further increase in flowability occurred. The order of efficiency of glidants for both host powders was fine silica greater than magnesium stearate greater than purified talc. The mode of action of the three glidants is discussed.

Calcium Phosphates↗
PubMed1978

Preventable anesthesia mishaps: a study of human factors.

A modified critical-incident analysis technique was used in a retrospective examination of the characteristics of human error and equipment failure in anesthetic practice. The objective was to uncover patterns of frequently occurring incidents that are in need of careful prospective investigation. Forty-seven interviews were conducted with staff and resident anesthesiologists at one urban teaching institution, and descriptions of 359 preventable incidents were obtained. Twenty-three categories of details from these descriptions were subjected to computer-aided analysis for trends and patterns. Most of the preventable incidents involved human error (82 per cent), with breathing-circuit disconnections, inadvertent changes in gas flow, and drug-syringe errors being frequent problems. Overt equipment failures constituted only 14 per cent of the total number of preventable incidents, but equipment design was indictable in many categories of human error, as were inadequate experience and insufficient familiarity with equipment or with the specific surgical procedure. Other factors frequently associated with incidents were inadequate communication among personnel, haste or lack of precaution, and distraction. Results from multi-hospital studies based on the methodology developed could be used for more objective determination of priorities and planning of specific investments for decreasing the risk associated with anesthesia.

Accident Prevention↗
PubMed1977

Hang gliding injuries in California.

Hang gliding continues to grow rapidly despite an increasing awareness of inherent risks. This report describes 144 injuries and 37 deaths in California during the period 1973 through 1975. More accidents were caused by inflight errors of judgment than by equipment failure. Nonfatal injuries showed a surprising number of severe upper extremity and spine injuries, while fatally injured pilots had combined head, neck, and chest trauma. A distinction between pilot education and experience is important. Improved safety equipment and education are recommended.

Accidents, Aviation↗
PubMed1977

Incidence and outcome of posttraumatic respiratory failure.

From 1972 through 1975, a total of 6,196 patients were admitted to San Francisco General Hospital Trauma Service, of whom 908 required admission to an intensive care unit and 390 required mechanical ventilation. Duration of mechanical ventilation was one week or less for 76%, two weeks or less for 90%, and four weeks or less for 97%. Survival in patients ventilated seven days or less was 64%, in patients ventilated 8 to 14 days it was 55%, and in patients ventilated 15 to 30 days it was 55%. The mortality for ventilated patients aged 20 to 49 years was 23% while for ventilated patients older than age 60 it was 53%. The average age of ventilated patients was 43. Use of controlled-pressure soft-cuff endotracheal tubes has eliminated tracheal-esophageal fistula and tracheal stenosis as causes of morbidity and mortality. Appropriate ventilator alarms have minimized fatalities due to mechanical equipment failure. Complications related to positive pressure ventilation, such as pneumothorax and subcutaneous emphysema, still occur in 12% to 18% of patients. In our patients who survived the acute respiratory distress syndrome, recovery of lung function was universal, and permanent disability was less than 1%.

Adolescent↗
PubMed1975

Effects of electromagnetic fields on fecundity in the chicken.

Egg production was reduced when young laying hens were kept in contact with metal cages while being continuously exposed to the following cw fields: a vhf field at a frequency of 260 MHz, with an incident power that decreased from 100 to 4mW during the experiment; a uhf field at a frequency of 915 MHz, with an incident power of 800 mW during the first 2.5 weeks, zero during the following week, and 200 mW for the remainder of the experiment; a uhf field at 2.435 GHz, with an incident power of 800 mW; an elf electric field at a frequency of 60 Hz, with a calculated value of field strength of 1600 V/m; an elf magnetic field at 60 Hz, with a value of magnetic flux density of 1.4G. With the exception of the hens exposed to the uhf field at 915 MHz, all other treated groups laid significantly less eggs than the controls (p smaller than or equal to 0.01). This reduction (similar 15% less than the controls) began with the first 4-week production period. The egg production curves for the hens exposed to the vhf field at 260 MHz and to the uhf field at 2.435 GHz were approximately the same beginning with the sixth week of production, and they maintained comparable production levels for the remainder of the experiment. An 8% total drop in production also was experienced in the group of birds exposed to the 915-MHz field, which pulsed because of equipment failure. Egg production rate curves for the birds in the elf electric and magnetic fields were substantially different from those exhibited by birds in the other electromagnetic fields. The birds in the E-field regained a production level comparable to the controls after 11 weeks production, whereas those in the B-field dropped to 31% production, which was approximately 40% poorer than the controls by the twelfth week of production. Fertility of cocks and hens was not affected by continuous low-power vhf and uhf near-zone electromagnetic exposure or elf electric or magnetic field treatment. Fertility was exceptionally good, except for the controls and the hens exposed to the elf electric field. The hatchs of fertile and of total eggs were not significantly influenced by exposure to any of the five fields. A considerably lower incidence of male chicks was noted in the elf magnetic field treatment (32.3%). The sex ratio in the other groups appeared to be relatively normal. No macroscopic abnormalities attributable to treatments were noted in the chicks hatched or in the dead embryos.

Animals↗
PubMedDate not supplied

Follow-up on hang gliding injuries in Colorado.

In a period extending from July 1973 to December 1975, seven fatal hang glider accidents were recorded in Colorado, all among experienced pilots. In addition, 11 serious nonfatal injuries were reported, which may represent only a fraction of those occurring. Accidents were noted to be multifactorial, caused by (1) pilot error, (2) equipment failure, (3) terrain hazards, and (4) possible design shortcomings. Accidents can be expected to decline in frequency with improved pilot training programs, grading and regulation of sites, and standardized safety clothing. No doubt over time, the less safe standard Rogallo wing will be replaced by the more stable Superkites and controlled collapsibles, which offer a higher safety margin. In the last analysis, this sport will remain a popular yet high risk endeavor (Figs. 2 through 5).

Adult↗
PubMed1979

[Monitoring equipment and electric everyday medicine. Prevention of failures (author's transl)].

Certain electrical equipments such as monitoring device, defibrillator, heart stimulator need in everyday medicine often deceive their users by not always supplying the expected services. This state of affair is due both to the lack of coordination between doctors and equipment fabricators, to lack of maintenance and to insufficient information from doctors. However, checking procedures guarantee a certain label of performance.

Electric Stimulation Therapy↗
PubMed2026

Fundamentals of pacemakers ECG interpretation - part 2.

BACKGROUND: Modern pacemakers incorporate arrhythmia-response algorithms, ventricular pacing minimization protocols, and safety mechanisms that generate ECG patterns indistinguishable from pathological AV block, sensing malfunction, or device-mediated tachycardia. Failure to recognize these algorithm-driven signatures leads to unnecessary interventions, misdiagnosis, and inappropriate device reprogramming. This manuscript is the second in a two-part series on pacemaker ECG interpretation. METHODS: We conducted a narrative review of peer-reviewed literature and device-specific documentation on algorithm-driven ECG behavior, synthesizing evidence across arrhythmia recognition, upper rate physiology, ventricular pacing minimization, mode switching, safety mechanisms, and hysteresis algorithms. RESULTS: Pacemaker-mediated tachycardia produces regular paced wide-complex tachycardia locked at the upper tracking rate, initiated by any event with retrograde VA conduction. Ventricular tachycardia is identified by QRS morphology diverging from the known paced pattern, absent pacing spikes, and AV dissociation. Upper rate Wenckebach behavior mimics Mobitz type I AV block; 2:1 upper rate response mimics second-degree AV block. Ventricular pacing minimization algorithms produce isolated nonconducted P waves and prolonged AV intervals that simulate pathological conduction disease. Mode switching causes abrupt rate drops misidentified as output failure. Ventricular safety pacing generates a conspicuously short, fixed AV interval. Three discrete pacing artifacts reflect AV-sequential cardiac resynchronization therapy (CRT), ventricular safety pacing in CRT, or His-bundle pacing with backup RV output. Rate and AV hysteresis produce pauses and wandering AV intervals mimicking oversensing or Wenckebach periodicity. CONCLUSIONS: Recognizing algorithm-driven ECG patterns requires knowledge of device timing intervals and refractory periods, which lets clinicians distinguish programmed behavior from true malfunction or cardiac arrhythmia.

Humans↗
PubMed2026

Physical reconfiguration of limb electrodes for Precordial Bipolar Lead acquisition: Morphological validation against digital subtraction.

BACKGROUND: The V2 - V1 Precordial Bipolar Lead (PBL) selectively evaluates the right-to-left retrosternal axis and has shown diagnostic value beyond the standard 12‑lead electrocardiogram. However, its use has been limited by the need for raw electrocardiographic data and post-processing software. This study evaluated whether a simple physical reconfiguration of limb electrodes could reproduce the digitally derived V2 - V1 morphology with sufficient accuracy for clinical application. METHODS: Thirty-seven subjects underwent two sequential 10-s 12‑lead recordings using a Cardiovit FT-1 electrocardiograph sampled at 1000 Hz. In the standard recording, the digital PBL was calculated as V2 - V1. In the second recording, the right-arm and left-arm electrodes were repositioned to the V1 and V2 sites so that Lead I directly recorded the retrosternal dipole. Signals were filtered, synchronized, and analyzed using median beats. Morphological agreement was assessed with Pearson correlation on Z-normalized signals, while absolute agreement was evaluated using Lin's concordance correlation coefficient (CCC), intraclass correlation coefficient (ICC (Lewis, 1931; Nehb, 1938 [1,2])), root mean square error (RMSE), and Bland-Altman analysis. RESULTS: Mean Pearson correlation between digital and physical PBL was 0.955 (SD 0.043), with segment-specific correlations of 0.953 (SD 0.054) for QRS and 0.967 (SD 0.052) for ST-T. Lin's CCC and ICC(2,1) were both 0.871 (SD 0.110), and RMSE was 0.091 (SD 0.049) mV. Bland-Altman analysis showed minimal bias (-0.008 mV). CONCLUSIONS: Physical acquisition of the V2 - V1 PBL achieved high agreement with the digitally derived signal, supporting a simplified analog method for broader clinical implementation.

Humans↗
PubMed1978

Permanent cardiac pacing in infants and children.

This clinical review details our 15 year experience with permanent cardiac pacemakers in 81 infants and children. Pacing was found inappropriate in one infant. The other 80 patients were paced because of congenital heart block [24], post-operative block [50], or sick sinus syndrome [6]. Maintenance of long-term pacing requires all too frequent re-operation for battery depletion [37%], lead related problems [32%] or wound dehiscence [31%]. Problems related to pacemaker size and the presence of a high myocardial threshold are particularly important in the pediatric patient. In spite of these problems, children requiring cardiac pacemakers can be extremely well, their prognosis depending almost entirely on the presence of underlying heart disease.

Adolescent↗
PubMed1978

Permanent pacing in the elderly.

A total of 89 patients, age 80 years or older at the time of initial permanent pacemaker implantation, were followed for 10 to 128 months [mean 32.7]. There were 54 males and 35 females. The mean age was 84.8 years. There were 51 patients age 80-84, 25 age 85-89, and 13 age 90-94. The actuarial 5-year survival was 45%. Complications occurred in 23 patients [40 episodes]. To date, 41 patients have already required at least one pulse generator replacement and 2 patients have already required 5 replacements. All but 3 patients were symptomatic prior to pacing and 56 were asymptomatic at last follow-up. Permanent pacing in the elderly is therapeutically rewarding and not associated with excess morbidity.

Actuarial Analysis↗
PubMed1978

Reprogramming of implanted pacemaker following external defibrillation.

This report describes reprogramming of a pulse generator consequent to cardiac defibrillation. Analysis of the explanted pulse generator revealed normal function. We tested the electrical properties of several defibrillators and our studies suggest that erratic electrostatic discharges at the time of paddle application before defibrillation may create a signal sequence capable of reprogramming the particular pulse generator by activating either the reed switch or internal electronics.

Electric Countershock↗
PubMed1978

Apparent malfunction of demand pacemakers due to spurious potentials generated by contact between two endocardial electrodes.

Malfunction of both temporary and permanent demand transvenous pacemakers was caused by contact between the two endocardial electrodes. Contact between these electrodes created spurious potentials which resulted in irregular inhibition of both demand units. The potentials were demonstrated by recording from the temporary wire. There was no interference with either pacemaker in the fixed rate mode and malfunction ceased when the temporary wire was removed.

Aged↗