PubMed Health⌕ Search

Biomedical subjects

P D Neufeld

Publications and source records attributed to P D Neufeld.

8 recordsLinked to original sources
PubMed1986

Observer error in blood pressure measurement.

This paper describes an experiment undertaken to determine observer error in measuring blood pressure by the auscultatory method. A microcomputer was used to display a simulated mercury manometer and play back tape-recorded Korotkoff sounds synchronized with the fall of the mercury column. Each observer's readings were entered into the computer, which displayed a histogram of all readings taken up to that point and thus showed the variation among observers. The procedure, which could easily be adapted for use in teaching, was used to test 311 observers drawn from physicians, nurses, medical students, nursing students and others at nine health care institutions in Ottawa. The results showed a strong bias for even-digit readings and standard deviations of roughly 5 to 6 mm Hg. The standard deviation for the systolic readings was somewhat smaller for the physicians as a group than for the nurses (3.5 v. 5.9 mm Hg). However, the standard deviations for the diastolic readings were roughly equal for these two groups (approximately 5.5 mm Hg).

Auscultation↗
PubMed1983

Results of the Canadian Anaesthetists' Society opinion survey on anaesthetic equipment.

Design shortcomings in carbon dioxide absorber bypasses and conical connectors in breathing circuits have been implicated in a number of fatal anaesthesia mishaps. In order to obtain users' views on the risks and benefits of these devices, a questionnaire was sent to 1,950 members of the Canadian Anaesthetists' Society. This paper presents a summary of the 313 responses received. Respondents were equally divided on whether the advantages of a CO2 absorber bypass outweigh the risks of accidental misuse. However, 53 per cent felt the bypass should not be removed from the absorber and 79 per cent favoured clearer labelling of the bypass setting. Accidental disconnections of conical fittings are daily occurrences. The most frequent site is the tracheal tube connector. Sixty-eight per cent of respondents use some method of securing the connectors, in most cases by taping them. The commonest reason given for not using commercial locking devices was that they are not available. Eighty-seven per cent of respondents use disconnect alarms when ventilating a patient.

Anesthesiology↗
PubMed1983

Safety of anaesthesia breathing circuit connectors.

Conical connectors used in anaesthesia breathing circuits are prone to accidental disconnections. We tested 291 connectors of 15 and 22 mm size and found that most did not comply with dimensional requirements in voluntary standards such as those issued by the Canadian Standards Association (CSA) and the American National Standards Institute (ANSI). However, measurements of disconnecting force showed no strong correlation with dimensional accuracy as determined by the standard gauge tests. When wrung together, metal-to-metal or plastic-to-plastic joints were considerably stronger than metal-to-plastic joints. Wrung joints were much stronger than connections made with a straight push, which showed no marked dependence on the type of material. Our results indicate that improved compliance with dimensional standards as determined by existing gauge tests will not improve connector performance. Rather, what is needed is a performance standard based on practical criteria. Under such a standard, some materials may prove unsuitable for friction-fit connections.

Anesthesiology↗
PubMed1975

Evacuated blood-collection tubes--the backflow hazard.

Five cases of nosocomial infection caused by Serratia marcescens were traced to backflow of blood from nonsterile evacuated blood-collection tubes. The mechanism of backflow was investigated theoretically and the conditions were determined under which backflow can occur. The theory was confirmed by experiments conducted on a simulated venous system and by measurements of the venous pressure in the brachial vein of a patient during application and removal of a tourniquet. Various possible solutions to the backflow hazard include strict adherence to correct venipuncture technique, sterilization of all blood-collection tubes, improvement of the vacuum in the tubes and incorporation of a check valve into the system.

Blood Specimen Collection↗