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Biomedical subjects

G C Bell

Publications and source records attributed to G C Bell.

14 recordsLinked to original sources
PubMed1988

Low-compliance, volume-controlled, high-frequency positive-pressure ventilation versus conventional ventilation during coronary artery bypass grafting.

Low-compliance, volume-controlled, high-frequency positive-pressure ventilation (HFPPV) was compared to conventional intermittent positive-pressure ventilation (IPPV) immediately before and after surgery in a series of ten patients who underwent coronary artery bypass grafting (CABG). Direct and indirect hemodynamic and respiratory variables were recorded and calculated. All patients were adequately ventilated with either HFPPV or IPPV. No significant differences in hemodynamic stability were noted either before or after cardiopulmonary bypass (CPB). Airway pressures were lowered significantly by HFPPV as compared to IPPV. This may be useful in cases in which increased airway pressure might be harmful due to decreased venous return and cardiac output (CO).

Aged↗
PubMed1988

Continuous-flow apneic ventilation with small endobronchial catheters.

This study compares gas exchange and hemodynamic parameters during bronchial insufflation with two different internal diameter (ID) catheters (2.5 and 1.4 mm) at a constant mean gas exit velocity. Anesthetized, paralyzed dogs were instrumented to monitor arterial, central venous, and airway pressures, blood gases, temperature, ECG, and ventilated using continuous flow apneic ventilation (CFAV) via 2.5-mm or 1.4-mm ID bronchial insufflation catheters positioned 1.25 bronchial diameter units (BDU) beyond the carina. Initially, flow was adjusted to provide adequate oxygenation and ventilation through the 2.5-mm ID catheters. After a 30-min stabilization, physiological parameters were recorded and the mean gas exit velocity was calculated. The 2.5-mm ID insufflation catheters were then replaced by 1.4-mm ID catheters and the bronchial insufflation flow adjusted so as to produce the same mean gas exit velocity as for the 2.5-mm ID catheters. After a 30-min stabilization period, physiological parameters were again recorded. No significant differences were noted in arterial, central venous, or airway pressures, temperature, heart rate, pH, PaCO2, and PaO2 between the 2.5-mm and 1.4-mm ID bronchial insufflation catheters. However, significantly less bronchial insufflation flow (69.7%) was required to maintain oxygenation and ventilation for the 1.4-mm ID bronchial insufflation catheters.

Animals↗
PubMed1978

Evalution of mechanical ventilators in a hyperbaric environment.

Four mechanical ventilators, the pneumatic Emerson, IMV bird, Urgency bird, and the Modified Mark 2 bird were tested in a hyperbaric chamber at depths up to 165 ft of sea water (FSW). All failed except the Emerson, which is the only machine recommended for chamber use at this time.

Evaluation Studies as Topic↗
PubMed1976

Acidosis, local anesthetics, and the newborn.

Four newborn infants were studied following maternal epidural block with lidocaine or mepivacaine. Each of these neonates, born with a pH of 7.23 or below in the umbilical vein blood, showed an elevated fetal-to-maternal concentration ratio, a possible manifestation of ion trapping of a weak base.

Acidosis↗
PubMed1975

Newborn blood levels of lidocaine and mepivacaine in the first postnatal day following maternal epidural anesthesia.

Distribution and elimination of lidocaine and mepivacaine were studies in 114 subjects after obstetric epidural anesthesia, Epinephrine significantly lowered the concentrations of lidocaine in the mothers' circulations by about 33 per cent, and the concentrations of mepivacaine by about 22 per cent. It also significantly altered their concentrations in the newborns' circulations at delivery and in the first 4 hours after birth. More mepivacaine than lidocaine crossed the placenta. The mepivacaine concentration in the cord blood was 36 to 47 per cent higher, and the mean fetal to maternal ratio for mepivacaine without epinephrine was 0.64, in contrast to 0.52 for the equivalent lidocaine group. Of importance was the long persistance of either drug in the newborns' circulation. Detectable levels of lidocaine and mepivacaine were present until 8 and 24 hours after birth, respectively. Pharmacokinetic models revealed that the long-term rate of disappearance of lidocaine was approximately three times as fast as that of mepivacaine. Computed half-times averaged 3 hours for lidocaine and 9 hours for mepivacaine.

Adult↗
PubMed1975

Improved epidural needle.

The standard Weiss epidural needls is well known to many obstetricians. Its principal advantage is easy manipulation, especially with the "hanging drop" sign. Among its disadvantages are the sharp Huber point, the difficulty of keeping the point in the midline using the conventional technic, and the possibility of dural puncture when the needle must be rotated. The modified needle overcomes these objections because the point is blunt and the elliptical flange soldered to the hub is rotated 90 degrees about the shaft. The resulting instrument is easier to use and is associated with a very low incidence of accidental dural puncture.

Anesthesia, Epidural↗
PubMed1972

Noise pollution.

Explore the source record for details and available documents.

Anesthesiology↗
PubMedDate not supplied

Implementing the US preventive services guidelines in a family practice residency.

BACKGROUND: Despite growing emphasis on preventive services, physicians still provide low levels of these services to their patients. Barriers to providing preventive services might be modified by more effective teaching models at the residency level. The purpose of this study was to evaluate a practice-based teaching model designed to increase resident compliance with the US Preventive Services Task Force Guidelines. METHODS: In Phase One of this study, physicians received didactic education about the US Preventive Services Task Force Guidelines. Subsequently, physicians' compliance with these recommendations was monitored. During Phase Two of the study, a comprehensive two-visit "Health Check" appointment was instituted. It incorporated a computerized health risk appraisal that was reviewed with patients. After the Health Check program was implemented, physicians' compliance with the guidelines was again audited. RESULTS: The chart audits revealed an overall increase in the level of preventive services provided by physicians from 31% in Phase One to 74% in Phase Two (P < .01). CONCLUSIONS: This type of teaching model can effectively increase the level of preventive services provided to patients in a family practice residency.

Adult↗