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Biomedical subjects

J W McIntyre

Publications and source records attributed to J W McIntyre.

At least 19 recordsLinked to original sources
PubMed1991

Self-perception of the ability to work in the cold.

Accumulating evidence of beneficial effects from physical exertion must be balanced against increased risk of cardiac arrest during performance. There is evidence that, by using such cues as heart rate, individuals can monitor their level of exertion perceptually. We undertook experiments to discover whether temperature and heart rate interact to affect self-perception when the effective temperature is moved downard from the comfort zone. In the first pilot study, 36 males practiced a new game, SwedeBall, for a period of 20 minutes. Twelve were randomly assigned to play at a temperature of 22 degrees C, another 12 to play at 0 degrees C, and the remaining 12 to play at -7 degrees C. The players showed tendencies toward an overall improvement in self-evaluations after brief practice, with more favorable responses when the temperatures were lower. In a second experiment on different days, 8 men pedaled a standard bicycle mounted as a wind trainer in a controlled environment chamber where the effective temperature was set at 26 degrees C, 8 degrees C, or -10 degrees C. The first 5-minute ride at each temperature was at a heart rate of 120 beats per minute (bpm), the second at 140 bpm, and a third at 160 bpm. We measured ratings of perceived effort (RPE), thermal impression, discomfort, perceived rate of speed, and projected endurance. The result confirmed that RPE was lowered by temperature when heart rate was constant. The data also showed that the lowered temperatures uniformly produced more favorable self-perceptions on the other four scales. The outcome is related to physiological problems that might arise when temperature depresses heart rate and reduces the experience of effort.

Acclimatization↗
PubMed1990

A unified approach to providing general anaesthesia monitoring with special reference to developing countries.

Information concerning general anaesthesia, monitoring and ergonomics has been assembled to present a plan for the introduction of necessary monitors into a department of anaesthesia. This includes reference to: (i) The need for instrumental monitors; (ii) Division of tasks between anaesthetist and monitor; (iii) User education; (iv) Anaesthetist/monitor interface; (v) Hospital infrastructure. Emphasis is placed on the continued need for anaesthetists to employ their own senses for monitoring in the traditional manner and the essential role instrumental monitors should play in helping trainees to refine and calibrate their clinical skills. It is suggested that in situations where neither mechanical ventilators are available nor instrumental monitors necessary to refine the conduct of general anaesthesia a transitional stage in evolution could be the presence of two persons with clearly defined responsibilities for all the anaesthesia tasks necessary during a safely conducted case.

Anesthesia Department, Hospital↗
PubMed1990

Monitoring regional anaesthesia.

Monitoring patients under regional anaesthesia is more challenging than patients under general anaesthesia but it has been somewhat neglected in anaesthesia literature. The fundamental differences are that during regional anaesthesia. 1. The patient is often awake. 2. Respiration is more difficult to measure. 3. Autonomic changes influence information obtained by pulse oximetry. 4. Monitoring personnel are at a greater risk of vigilance decrement. A review of reported complications during regional anaesthesia enabled conclusions to be reached regarding monitoring policies in an institution. These include particular reference to spontaneous respiration and cerebral function. The need for an appropriately skilled person monitoring the patient in the operating room at all times is emphasized, as is the necessity for education appropriate for the skills they may have to exercise even on rare occasions. Specific instruction in vigilance decrement avoidance should be part of that curriculum.

Anesthesia, Conduction↗
PubMed1989

Application of automated human voice delivery to warning devices in an intensive care unit: a laboratory study.

Environmental concerns about the delivery of warning messages in intensive care units exist in the belief that conventional non-verbal alarm signals are perceived to be threatening by some patients. There is also a significant opportunity for error in interpretation by fatigued or anxious personnel. A laboratory study was undertaken to determine whether human subjects made fewer errors when messages regarding ICU related tasks were delivered by tape recorded human voice than by the non-verbal signals derived from devices in the ICU. Results demonstrated a statistically significant superiority of human voice messages over non-verbal signals. It is concluded that taped human voice messages merit field trials in intensive care units.

Computer Systems↗
PubMed1989

Laryngoscope design and the difficult adult tracheal intubation.

Clinical examination of a patient is very likely to reveal the factors making tracheal intubation difficult and thus increasing the likelihood of a traumatized temporo-mandibular joint or mouth. Although laryngoscopes and bronchoscopes incorporating fiberoptic visual devices are invaluable they are usually only employed for extremely difficult patients. Other laryngoscopes exist in a variety of designs and can be categorised according to the particular problem they address: (i) prominent sternal region, (ii) narrow space between the incisors, (iii) reduced intraoral space and, (iv) the anteriorly positioned larynx. An atraumatic tracheal intubation will be assisted if the laryngoscope blade to be used is selected on the basis of the anatomic difficulties prescribed by the patient. The Miller, Jackson-Wisconsin, Macintosh, Soper, Bizarri-Guffrida, and Bainton blades together with appropriate handles and fittings comprise a group from which selection can be made.

Adult↗
PubMed1988

Affective responses to commercial and experimental auditory alarm signals for anaesthesia delivery and physiological monitoring equipment.

The affective response of subjects to the sounds of commercial and experimental auditory alarm signals was tested using a standard experimental protocol for measuring mood states and changes. Both types of signal evoked affective response. The commercial signals, however, evoked more response than the experimental signals, and that response was more negative in affect. A subset of the experimental signals, distinguished by specific acoustic characteristics, evoked particularly low levels of affect. The implications of low-affect alarms for the operating room are discussed.

Adult↗
PubMed1985

Audible alarm signals for anaesthesia monitoring equipment.

To address the problem of auditory alarms on anaesthesia monitoring and delivery devices whose signal is masked by the noises of other operating room equipment, a set of signals having the characteristics of spectral richness, frequency modulation, and temporal patterning were electronically generated, and were tested for detectability against operating room equipment noises in a laboratory setting. A set of signals was identified which can, under these circumstances, be detected with at least 93% accuracy at -24 dB signal-to-noise ratio.

Anesthesiology↗
PubMed1979

Anesthesia equipment malfunction: origins and clinical recognition.

Equipment malfunction is a problem of particular importance during anesthesia and resuscitation. A review of published reports shows that the most common clinical events involve endotracheal tubes, the inspired oxygen concentration, the volume of inspired anesthetic vapours and gases, and pressures in the breathing or ventilation system. It is concluded that protection of a patient from equipment malfunction depends on: (a) appropriate application of standards set by a national standards association; (b) careful evaluation of equipment prior to purchase; (c) comprehension of equipment function by the user; (d) conscientious routine servicing of all systems concerned with anesthesia and resuscitation, and checking after service and before clinical use; (e) preanesthesia testing of equipment, including the use of an oxygen analyser in the breathing circuit; (f) early inclusion of equipment malfunction in the differential diagnosis of events during anesthesia; and (g) rapid action that cannot present a new hazard to the patient to correct the results of apparatus malfunction.

Accidents↗
PubMed1978

An assessment of operating room environment air contamination with nitrous oxide and halothane and some scavenging methods.

This study was designed to assess operating room contamination with nitrous oxide and halothane when nitrous oxide 3 1/min and oxygen 2 1/min containing halothane one per cent were passed into a semiclosed circle absorber system from which the patients' lungs were ventilated with an Ohio ventimeter through a cuffed tracheal tube, with the exhaled gas vented to the floor. The normal room ventilation did not consistently maintain levels below the suggested amounts, which are nitrous oxide 25 ppm and halothane 2 ppm. Careful daily check for and correction of high and low pressure leaks combined with the use of a Foregger scavenging device (7--351--005) and continuous wall vacuum accepting approximately 22 1/min enabled geometric mean values below the suggested levels to be achieved. The Protection Filter Foregger 7--365--001 was only effective in removing halothane and only if the plastic holder provided was radically modified. Attention is drawn to the numerous factors influencing the magnitude of contamination, aspects of controlling it, and the necessity to cope with the problem of dealing with scavenged gases and vapours.

Air Pollutants↗