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Biomedical subjects

I J Gilmour

Publications and source records attributed to I J Gilmour.

18 recordsLinked to original sources
PubMed1995

Safety and efficacy of a ventilator database interface.

This report describes a ventilator dysfunction that arose during the mechanical ventilation of a lung transplant recipient. The problem was discovered because the data on the computer-based information management system (CIMS) was different from that on the ventilator's dials. This incident is important because of the continued extensive use of analog mechanical ventilators, the increasing popularity of CIMS, and the patient safety implications of the incident.

Adult↗
PubMed1995

The effects of circuit and humidifier type on contamination potential during mechanical ventilation: a laboratory study.

BACKGROUND: This study was undertaken because of concerns that ventilator humidifiers could be exacerbating the problem of nosocomial pneumonia in patients receiving mechanical ventilation. METHODS: Four different brands of humidifiers were used in conjunction with a siemens Servo 900B mechanical ventilator (Siemens Life Support Services, Solna, Sweden). In the first part, the ventilator was operated with humidifiers filled with contaminated water at room temperature. The viability of airborne particles and the effect of flow rates on the number of particles produced were assessed. In the second part, we measured the effect of time and temperature on bacterial survival in humidifier chambers. Because only bubble-through humidifiers were determined to produce infectious particles, the speed with which a contaminated bubble-through humidifier could infect circuit condensate was also determined. Aliquots of chamber water and circuit condensate, as well as air samples and distal circuit swabs, were cultured. RESULTS: Humidifiers other than bubble-through humidifiers did not produce aerosols. Particle production by bubble-through humidifiers varied directly with flow rate (R2 = 0.91). Chamber temperatures did not affect chamber colony counts except in bubble-through humidifiers. Although chamber colony counts in bubble-through humidifiers decreased with time, organisms remained viable throughout the study. When bubble-through humidifiers were heated, both condensate and effluent gas became heavily contaminated within minutes of flow initiation. CONCLUSIONS: Bubble-through humidifiers produce aerosols that readily contaminate both circuit condensate and effluent gas. Avoiding bubble-through humidifiers should improve patient safety while allowing changes in practice that can result in significant cost savings.

Aerosols↗
PubMed1994

The effect of heated wire circuits on humidification of inspired gases.

We performed this study to determine the effect of heated wire circuits on humidity delivered by several humidifiers commonly used during anesthesia. Humidifier bases from three manufacturers with several humidifying chambers for each base were tested using both heated and unheated circuits. Delivered humidity and circuit temperature were measured at the distal end of the circuit. Each chamber was tested under both continuous flow (CF) and intermittent flow (IF) conditions. IF was provided by a Servo 900 B ventilator. Adjustments of flow and volume were made for pediatric chambers. At 90 L/m CF, humidifier performance was unsatisfactory with both heated and unheated circuits. At 15 and 45 L/m CF, both distal circuit temperature (DCT) and humidity were within acceptable limits; unheated circuits delivered more humidity than heated circuits (P < 0.05). Relative humidity was lower at 45 L/m CF than at 15 L/m (P < 0.05). During IF while all chambers provided satisfactory humidity, humidity was greater when unheated circuits were used. We conclude that when heated circuits are used, humidifying systems may fail to deliver 100% humidity to patients.

Adult↗
PubMed1993

Clinical performance of a blood gas monitor: a prospective, multicenter trial.

OBJECTIVE: To prospectively assess the clinical performance of a fluorescent optode-based blood gas monitoring system that is designed to perform arterial pH, PCO2, and PO2 measurements as frequently as clinically required without violating the integrity of the arterial catheter tubing system or permanently removing blood from the patient. DESIGN: A prospective, multicenter study to compare modern blood gas analyzer measurements with the coinciding measurements of the blood gas monitoring system. SETTING: Four intensive care units (ICUs) in academic centers with varying patient populations, blood gas measurement routines, and blood gas laboratory facilities. PATIENTS: Adult ICU patients (n = 117), with appropriately functioning radial arterial catheters in place, who were assessed as likely to require multiple arterial blood gas measurements for > or = 2 days. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 117 patients had 1,341 concurrent blood gas analyzer and monitor measurements of arterial pH, PCO2, and PO2 over a 1- to 4-day period. The range of values were 7.14 to 7.64 for arterial pH, 19 to 98 torr (2.5 to 13.0 kPa) for PaCO2, and 38 to 413 torr (5.1 to 54.9 kPa) for PaO2. Linear regression analysis of the optode-based monitor compared with the electrode-based blood gas analyzer demonstrated r2 values of .85 for pH, .92 for PCO2, and .94 for PO2. Comparative statistical analyses for bias (mean difference between analyzer and monitor) and precision (standard deviation of the mean difference [+/- SD] between analyzer and monitor) were respectively:-0.004 and +/- 0.027 for pH; -0.8 torr (-0.11 kPa) and +/- 2.4 torr (0.32 kPa) for PCO2; -2.2 torr (-0.31 kPa) and +/- 8.7 torr (1.2 kPa) for PO2. CONCLUSIONS: Clinical performance of this fluorescent, optode-based blood gas monitoring system demonstrates stability, consistency, and accuracy comparable to modern blood gas analyzers. This system withstood the normal abuse and rigors of clinical conditions common to the ICU while reliably performing in critically ill patients for up to 80 hrs. Use of the device did not significantly alter the function or longevity normally expected from a 20-gauge radial artery catheter. We submit that this blood gas monitoring system can replace the use of blood gas analyzers for ICU patients with indwelling arterial catheters.

Adolescent↗
PubMed1992

Perioperative stroke.

Explore the source record for details and available documents.

Cerebrovascular Circulation↗
PubMed1991

Preoperative optimization of cardiovascular hemodynamics improves outcome in peripheral vascular surgery. A prospective, randomized clinical trial.

The hypothesis that optimizing hemodynamics using pulmonary artery (PA) catheter (preoperative 'tune-up') would improve outcome in patients undergoing limb-salvage arterial surgery was tested. Eighty-nine patients were randomized to preoperative tune-up either in the surgical intensive care unit (SICU) (group 1) or the preinduction room (group 2) or to control (group 3). The tune-up consisted of fluid loading, afterload reduction, and/or inotropic support to achieve predetermined endpoints. Patients with a PA catheter had significantly fewer adverse intraoperative events (p less than 0.05), less postoperative cardiac morbidity (p less than 0.05), and less early graft thrombosis (p less than 0.05) than the control group. The overall study mortality rate was 3.4%, with a mortality rate of 9.5% in the control group and 1.5% in the PA catheter groups. There were no differences in ICU length of stay (LOS), hospital LOS, or total hospital costs, although the percentage of cost from complications was higher in group 3 (p greater than 0.05). In this group of patients, preoperative cardiac assessment and optimization is associated with improved outcome.

Aged↗
PubMed1991

Effect of kidney dysfunction on lung volume in patients with diabetes.

OBJECTIVE: Over several years, one of the authors observed what appeared to be a relationship between a decrease in total lung capacity (TLC) and insulin-dependent diabetes mellitus (IDDM) in patients who were candidates for kidney transplantation. RESEARCH DESIGN AND METHODS: In an effort to define this potential relationship, pulmonary function tests (PFTs) were reviewed on all available kidney transplant candidates between 1983 and 1986. The patients were divided into two groups--those with kidney failure caused by IDDM (group 1) and those with kidney failure from other causes (group 2). A third group (control subjects) of volunteers with IDDM but without evidence of kidney failure was evaluated by PFTs in an attempt to determine whether IDDM without kidney failure was also associated with a decrease in TLC. RESULTS: Demographics of the two groups with kidney failure were similar. However, the duration of IDDM in the volunteers with IDDM was significantly shorter than in group 1 patients (19.6 vs. 25.9 yr). The TLC of group 1 patients was significantly smaller than the TLC of both the group 2 patients and the volunteers with IDDM. CONCLUSIONS: We believe that these data suggest that the association between IDDM and decreased TLC is the result of IDDM and not kidney failure. Because our volunteers with IDDM were significantly younger than the patients with IDDM and kidney failure, we can draw no conclusions about any separate contribution of kidney failure to changes in TLC in people with IDDM.

Adult↗
PubMed1980

Preextubation ventilatory measurements in newborns and infants.

Maximum inspiratory pressure, inspiratory capacity, and minute ventilation were measured in a group of infants prior to extubation to determine whether these parameters predicted successful extubation. Data obtained suggested that maximum inspiratory pressure and inspiratory capacity more accurately assessed the patient's ability to tolerate extubation than minute ventilation, pH, PCO2, or respiratory rate. A maximum inspiratory pressure of greater than 33 torr and an inspiratory capacity of greater than 150 ml/m2 were predictive of successful extubation.

Female↗
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↗
PubMed1975

Nitrogen analyzer adaptation for use in the presence of halogenated anesthetics.

Interposition of activated carbon between a nitrogen analyzer needle valve and gas mixtures containing halothane, methoxyflurane, enflurane, or isoflurane eliminated the interfering effects of these agents, but added sampling delays. Placement of a carbon-filled Swinney adaptor in the sampling line between the needle valve and analyzer also eliminated the interference. Linearity of response (range 0 to 80 per cent N2) and sampling delay (40 msec) were unchanged. The 90 per cent fall time (step change 80 to 0 per cent N2) increased from 35 to 100 msec. This adaptation allows rapid analysis of nitrogen concentrations during general anesthesia.

Anesthesia, General↗