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Biomedical subjects

D B Craig

Publications and source records attributed to D B Craig.

At least 55 records · Page 3Linked to original sources
PubMed1980

Implementation of Canadian Standards Association Z168.3-M 1980 Anaesthetic Gas Machine Standard: the Manitoba experience.

The Province of Manitoba Anaesthetic Machine Program, completed in June 1980, accommodated Canadian Standards Association Standard Z168.3-M 1980. "Continuous Flow Inhalation Anesthetic Apparatus (Anesthetic Machines) for Medical Use". The goal of the program was to have all anaesthetic machines in hospitals in the province with the same basic design and safety features: "oxygen right"; characteristic oxygen knob profile; oxygen supply pressure failure device and alarm; standardized "oxygen flush" mechanism; pipeline inlets and pressure gauges; uniform color coding; standardized common gas outlet; pin indexed cylinder yokes; descriptive labels concerning safety devices; check valves within machine piping. Open group-purchase tenders were invited for both machine upgrading and replacement. Of 212 machines surveyed, 127 were upgraded (cost $100,000), 65 were replaced (cost $175,000), three were already satisfactory, and 17 were no longer required and were removed permanently from service. The Manitoba Program provided a satisfactory solution to a most important problem.

Anesthesia, Inhalation↗
PubMed1980

Anaesthetic machine pipeline inlet pressure gauges do not always measure pipeline pressure.

Some anaesthetic gas machines have pipeline inlet pressure gauges which indicate the higher of either pipeline pressure, or machine circuit pressure (the pressure distal to the pressure reducing valve, and proximal to the flowmeter control valve). Failure by the operator to appreciate this feature may in specific circumstances lead to a delayed appreciation of pipeline malfunction or disconnection. The Canadian Standards Association Z168.3-M1980 Anaesthetic Gas Machine Standard requires pipeline inlet gauges which measure only pipeline (hose) pressure. Existing machines should be modified to accommodate this requirement.

Anesthesia, Inhalation↗
PubMed1980

A post-anaesthetic follow-up program.

Experience with an in-hospital post-anaesthetic follow-up program is reported. Visits are made by a Registered Nurse, a hospital employee working under the direction of the Head of the Department of Anesthesia. Over a three-year period 21,116 of 39,239 patients receiving anaesthetics were visited. Those not visited were mainly outpatients or patients discharged early following minor surgery. Anaesthetic related minor complications were noted in 8.15% of the patients seen in follow-up. Major complications occurred in 0.37% of patients seen.

Adult↗
PubMed1980

Sudden interruption of gas flow through a Schrader oxygen coupler unit.

The flow of oxygen to an anaesthetic gas machine suddenly and completely stopped during the course of a general anaesthetic. The cause of the failure was traced to a Schrader oxygen coupler check unit. During servicing, one component of the check unit had inadvertently been replaced by a similar but inappropriate component. Interruption of oxygen flow resulted from a loss of contact between two components of the check unit. This incident raises questions about the basic design and safety of Schrader coupler check units.

Anesthesia, Inhalation↗
PubMed1980

Halophilic Vibrio sepsis.

We have described a patient with fulminant sepsis and bullous skin lesions due to L + Vibrio. The histologic features of these lesions as well as the rapid onset of refractory shock and complete heart block at least suggest that potent bacterial toxins are involved in the pathogenesis of disease caused by this "unnamed lactose-positive marine Vibrio."

Aged↗
PubMed1979

Safety modifications to mobile hypothermia units.

Major safety deficiencies of older mobile hypothermia units are described. Problems include absence of high or low temperature output limitation or of visual warning of abnormal operating temperatures. Modifications described provide two high temperature thermostats and one low temperature thermostat, which shut the unit down if the temperature limits are exceeded. Visual and auditory alarms were also added. Operators of mobile thermal units should be aware of the major safety deficiencies of some older models, and should insist on either modification, where appropriate, or replacement.

Anesthesiology↗
PubMed1976

Measurement of 'closing volume' initiated from functional residual capacity.

Comparison of the nitrogen method closing volume (CV) test, with oxygen inspiration initiated at residual volume (RV method) and functional residual capacity (FRC method), was made in 91 seated normal subjects. For RV and FRC methods, respectively CV%VC (mean+/-SD) was 14.4% (+/-6.2) and 17.5%(+/-7.5) (P=0.005); slope of Phase III of CV trace was 0.99% N2/1 (+/-0.76) and 1.66% N2/1(+/-1.07) (P=0.005); size of cardiogenic oscillations was 1.05% N2(+/-0.42) and 1.21% N2(+/-0.40) (P=0.001). These data confirm earlier predictions, based on a calculated increased lung top to bottom N2 gradient in the FRC method. Support for this mechanism was obtained in 5 additional normal subjects in whom the increased CV%VC, slope of Phase III and size of cardiogenic oscillations with the FRC method were eliminated when the top-to-bottom N2 gradient was reduced by breathing a reduced FIN2. Measurements made using the classical RV method cannot be directly compared to those using the FRC method.

Adult↗
PubMed1976

The effect of acute, intensive cigarette smoking on maximal expiratory flows and the single-breath nitrogen washout trace.

The effect of acute, intensive cigarette smoking on forced vital capacity and the single-breath expired N2 trace was studied in 82 smokers. There were significant decreases in the "effort-dependent" tests, such as peak flow and 1-sec forced expiratory volume, but no change in the more "effort-independent" tests, such as maximal mid-expiratory flow and maximal expiratory flow at 25 per cent of the vital capacity. Closing volume was unchanged in absolute terms and as a percentage of vital capacity. Closing capacity was unchanged in absolute terms and as a percentage of total lung capacity, but there was a significant increase in the slope of Phase III of the N2 washout curve after the acute smoking session. The tests of function that changed significantly after acute, intensive smoking were the ones that improved in 52 subjects who modified their smoking habits. The data suggest that acute, intensive cigarette smoking may be associated with an increase in resistance to air flow in the larger airways or a reduction in effort, and with increased nonuniformity of intraregional distribution of ventilation.

Adult↗
PubMed1976

Effect of modification of the smoking habit on lung function.

The effect of smoking cessation or modification on lung function was determined during a 48-week period. In a large number of the cigarette smokers, a disturbance of lung function was not revealed by conventional tests, such as the 1-sec forced expiratory volume; however, an abnormality was often demonstrable in tests that may reflect alterations in small airways, such as closing volume and Phase III of the single-breath expired N2 curve. There was no relation between the degree of abnormality of lung function and the presence of respiratory symptoms, but there appeared to be a relationship to lifetime smoking history, the heaviest smokers having the poorest function. Cessation, or more than 25 per cent decrease in the number of cigarettes smoked, was attened by improvement in the slope of Phase III of the N2 washout curve, closing volume, and closing capacity, as well as forced vital capacity, 1-sec forced expiratory volume, and peak flow. Resumption of smoking after cessation was attended by a deterioration in the slope of Phase III and closing capacity. The data suggest that the functional abnormalities in smokers are related to smoking and are at least partially reversible by cessation or significant modification of the smoking habit.

Adolescent↗
PubMed1976

Closing capacity measurement during general anesthesia.

A modification of the single-breath nitrogen closing volume (CV) test allows measurement of closing capacity (CC) during general anesthesia. In the modification, inspiration and expiration are mechanically produced by a hydraulically powered cylinder. For 14 awake, normal subjects results of the CV test performed using this mechanical method differed that those obtained following spontaneous inspiration and expiration. Mean (+/-SE) CC's were 2.25 (+/-0.15) and 2.42 1 (+/-0.14) (P less than 0.01) using spontaneous and mechanical methods, respectively. The slopes of Phase III of the CV traces were 2.24 (+/-0.27) and 2.66 per cent N2/L (+/-0.32) (P less than 0.01), respectively. To eliminate differences due to measurement technique, the modified CV test was used both before and during anesthesia with halothane in 70 per cent N2 in 11 normal, supine, spontaneously breathing subjects. CC's were 1.89 l (+/-0.16) before and 1.84 l (+/-0.15) during anesthesia (P greater than .5). Mean functional residual capacities (FRC) by the closed-circuit helium method were 1.77 l (+/-0.15) before and 1.45 l (+/-0.17) during anesthesia (P less than .001). With CC unchanged and FRC decreased following induction, CC/FRC increased from 1.07 (+/-0.08) to 1.37 (+/-0.11) (P less than .005), suggesting increased small-airway closure during anesthesia.

Adult↗