Search PubMed⌕ Search

Biomedical subjects

J Hedley-Whyte

Publications and source records attributed to J Hedley-Whyte.

At least 37 records · Page 2Linked to original sources
PubMed1981

Bacterial fouling of a hospital closed-loop cooling system by Pseudomonas sp.

During the summer of 1979 the air-conditioning system at a hospital in Boston deteriorated, and this led to total failure of some chilling units. Patient care and operating-room areas were affected. Investigation of the problem ruled out mechanical and electrical causes, but revealed a strain of Pseudomonas sp. biofouling heat transfer tubes of the closed chilled water system. The pseudomonads apparently were stimulated to grow by low concentrations of ethylene glycol antifreeze. The proximate source of these organisms was an expansion tank located in a 33 degrees C environment. The organisms probably originated from the potable water supply of the hospital. Fouling was eventually cleaned by prolonged and expensive treatments of the closed chilled water system. Pseudomonas sp. is frequently isolated from hospital-acquired infections at our institution (Beth Israel Hospital, Boston, Mass.); however, our studies with fluorescent dye tracers indicated that organisms were prohibited from entering patient areas via contaminated water from the chillers. Microbiologists must become cognizant of seemingly unimportant microbial environments within hospitals that may indirectly contribute to hospital-acquired infections.

Air Conditioning↗
PubMed1981

Mechanisms of renal dysfunction during positive end-expiratory pressure ventilation.

Twenty-seven anesthetized dogs were studied to determine the effects of intrarenal blood flow distribution, hepatic congestion, and cardiac output (Q) and/or intravascular volume on renal function during ventilation with positive end-expiratory pressure (PEEP) of 10 cmH2O. In 10 dogs intrarenal blood flow distribution, as determined by the radioactive-microsphere technique, remained unchanged although PEEP caused a significant antidiuresis and antinatriuresis. The selective release of hepatic congestion during PEEP in eight animals by means of a vena cava to jugular venous shunt circuit did not restore renal function. Nine dogs were transfused with 25 ml/kg of autologous blood during PEEP. Although Q remained at only 70% of control, renal blood flow and renal function (glomerular filtration rate, urinary sodium excretion, urine output, osmolar clearance, and free water clearance) were restored to control values. Our results suggest that the impairment in renal function during PEEP is not caused by changes in intrarenal blood flow distribution, Q, or hepatic congestion, but rather by a decrease in intravascular volume.

Animals↗
PubMed1980

Hazards of hospital bulk oxygen delivery systems.

Numerous problems can occur with liquid oxygen delivery systems, in part because of the complexities of such systems. These systems must comply with guidelines of the Joint Commission on Accreditation of Hospitals. During the past year, 18 major problems with the liquid oxygen delivery system have occurred at the authors' hospital. Five times, false alarms have resulted from calibration drift in line pressure sensors. Thrice, excessive depletion of the reverse supply has occurred because of pressure imbalance between the main and reserve systems. Twice, excessive depletion of the reserve supply occurred owing to failure of the vacuum seal on the reserve supply vessel. Eight other potentially serious mishaps have also been reported. These problems, which are inherent in liquid oxygen delivery systems, are for the most part preventable.

Accident Prevention↗
PubMed1980

Effects of renal and hepatic venous congestion on renal function in the presence of low and normal cardiac output in dogs.

We investigated the effect of acute renal vein and hepatic vein hypertension induced by partial balloon-occlusion of the abdominal inferior vena cava (AIVC-O) and the thoracic inferior vena cava (TIVC-O) on systemic and renal hemodynamics and renal function in 13 dogs anesthetized with pentobarbital. When a renal vein pressure of 13 cm H2O was induced by AIVC-O, cardiac output, stroke volume, central venous pressure, renal blood flow, and renal function (GFR, free water clearance, osmolar clearance, urine output, urinary sodium excretion, fractional sodium excretion) decreased significantly. When systemic hemodynamics were restored to control values by transfusion of autologous blood (mean of 9 ml/kg body weight) while renal vein pressure was kept elevated, renal function also was restored. A hepatic venous pressure of 13 cm H2O then was induced by TIVC-O. The effects on systemic hemodynamics and renal function were very similar to those observed during AIVC-O. When systemic hemodynamics were restored to control values by transfusion (mean of 9 ml/kg), while hepatic venous hypertension was maintained by TIVC-O, renal function also was restored. Despite significant changes in natriuresis and diuresis, intrarenal blood flow distribution, as determined by the radioactive microsphere technique, remained essentially unchanged throughout. We conclude that renal and hepatic congestion induced by partial AIVC-O and TIVC-O do not, per se, alter renal function significantly.

Animals↗
PubMed1979

Prediction of outcome of surgery and anesthesia in patients over 80.

We studied the outcome of surgery in 500 patients over 80 years of age. Hospital mortality within one month of surgery was 6.2%. The American Society of Anesthesiologists class 1 to 5 preoperative evaluation scale was useful in predicting death--less than 1% of class 2 patients died, 4% of class 3, and 25% of class 4. Six of seven perioperative deaths were caused by mesenteric infarction. Myocardial infarction was the leading cause of postoperative death. Twenty-four percent of 141 patients who underwent upper abdominal surgery required controlled endotracheal ventilation for more than 24 hours postoperatively; 57% after intrathoracic surgery; and only 2% after surgery that did not enter pleura or peritoneum. Forty-seven patients underwent gallbladder surgery, and 27 peripheral underwent vascular surgery without any hospital fatality. Enflurane appears to be a safe general anesthetic for sick, elderly patients.

Aged↗
PubMed1977

End-respiratory pressure ventilation and sulfobromophthalein sodium excretion in dogs.

Sulfobromophthalein sodium (BSP) 25 mg/kg body wt was given as a single iv injection to 32 fasted dogs. Serum samples at 3, 5, 10, 20, 30, 45, 60, 80, and 120 min postinjection were analyzed for total concentration of BSP and from 30 to 120 min for percent conjugated BSP. Four groups were compared: spontaneous ventilation; intermittent positive-pressure ventilation (IPPV) and continuous positive-pressure ventilation (CPPV) (2 groups). During CPPV, one group of dogs was given a continuous infusion of cholecystokinin octapeptide (CCK-8, 1 ng/kg per min). Central venous pressure averaged 11.3 +/- 0.7 (SE) cmH2O in dogs with CPPV + CCK-8 and 11.8 +/- 0.8 (SE) cmH2O in dogs with CPPV alone. At 3, 5, and 10 min postinjection serum BSP levels were similar in all groups. From 30 to 120 min postinjection serum levels of both free and conjugated BSP were higher in dogs ventilated with CPPV alone than in any other group (P less than 0.01). Dogs given CCK-8 during CPPV had serum BSP levels that were statistically similar to dogs breathing spontaneously or ventilated with IPPV. We conclude that CPPV impairs BSP excretion. This effect is counteracted by CCK-8.

Airway Resistance↗
PubMed1976

Bulk oxygen and nitrous oxide delivery systems: design and dangers.

A survey of hospitals with anesthesia residency training programs was undertaken to determine the frequency and types of complications encountered with the use of bulk supplies of oxygen and nitrous oxide. Of the responding hospitals, 98 per cent dispense oxygen from a central source and 80 per cent dispense nitrous oxide from a central source. Nearly a third of the hospitals responding reported the occurrence of serious or potentially serious accidents related to their bulk gas delivery systems. In three instances accidents resulted in patient deaths. More than half of the reported incidents were decreases in oxygen pipeline pressure, often resulting in insufficient delivery of oxygen for clinical use. Most complications related to pipeline accidents could have been prevented by observance of National Fire Protection Association regulations. Anesthesiologists should be familiar with these regulations and should understand the designs of gas delivery systems in their institutions.

Equipment and Supplies, Hospital↗
PubMed1976

Solubility of 92 in blood with different hemoglobin concentrations at low temperatures.

The Brunsen solubility coefficients for O2 in blood obtained from healthy nonsmoking subjects have been determined at 0, 6, and 12 degrees C for bloods of hemoglobin concentrations 5.6, 10.2, 15.7, and 22.5 g/100 ml. Direct gasometric measurements show that blood has a relative solubility (alphabeta/alphah2o) different for each hemoglobin concentration but constant for any given hemoglobin concentration at the temperatures studied (0.6, and 12 degrees C). For hemoglobin concentrations 5.6, 10.2, 15.7, and 22.5 g/100 ml alphabetao degrees C/alphabeta 12 degrees C rations were 1.36, 1.35, 1.35, and 1.35, respectively. The alpha H20(0 degrees C)/alpha H20(12 degrees C) ratio is 1.34. Consequently, it was possible to construct a table for the Brunsen solubility coefficients for O2 in blood from O to 15 degrees C of different hemoglobulin concentrations. Values from 10 to 15 degrees C published in the Biologal Hanbook, Respiration and Circulation, based on extrapolations from previous direct measurements of temperatures from 18 to 37 degrees C differ only 1% from our present results.

Adult↗
PubMed1976

Effect of sodium para-aminosalicylate on oxygen affinity in normal, sickle and fetal human blood.

Sodium para-aminosalicylate (sodium salt of 2-hydroxy-4-aminobenzoic acid, Na-PAS) lowers the oxygen affinity of normal adult human placental, heterozygous and homozygous sickle cell anemic whole blood at 37 degrees C. The reduction of oxygen affinity is related to the type of hemoglobin in the blood. The mean P50 +/- S.E. at pH 7.40 for normal, placental, heterozygoud and homozygous sickle cell anemic blood in 26.2 +/- 0.1, 20.8 +/- 0.3, 26.8 +/- 0.3 and 31.0 +/- 0.5 mm Hg; in the presence of 5.7 mmol of Na-PAS per liter of blood the P50 values are increased to 28.0 +/- 0.3, 22.9 +/- 0.8, 30.5 +/- 0.6 and 33.9 +/- 0.3 mm Hg, respectively. The Bohr effect in normal and placental blood at this Na-PAS concentration is essentially unchanged: in heterozygous and homozygous sickle cell anemic blood, the Bohr factor (deta log P50/deta pH) is reduced from -0.48 +/- 0.02 to -0.41 +/- 0.01 and from -0.53 +/- 0.03 to -0.48 +/- 0.01. The Hill constants (n) of normal and placental blood are not affected by Na-PAS. In homozygous and heterozygous sickle blood, high concentrations of Na-PAS (22.9 mmol/l) decrease the Hill constant from 2.55 to 2.35 and from 2.56 to 2.28, respectively. Na-PAS is more firmly bound to red blood cells than to plasma. The binding of Na-PAS is probably primarily ionic in nature since the drug can be almost completely removed from blood components by dialysis. The changes in oxygen affinity caused by Na-PAS are consistent with conformational changes (R leads to T) which enhance the presence of deoxyhemoglobin.

Adult↗
PubMed1975

Aerosol polymyxin and pneumonia in seriously ill patients.

Pneumonia caused by Pseudomonas aeruginosa occurs frequently in critically ill patients and is associated with a mortality rate of 70 per cent. An aerosol of polymyxin B was administered (2.5 mg per kilogram per day) to the upper airways of 292 patients in a respiratory-surgical intensive-care unit during a seven-month period, in an attempt to prevent Ps. aeruginosa pneumonia. Although only one of the patients studied acquired pneumonia due to Ps. aeruginosa, 10 others acquired pneumonia caused by a polymysinx-resistant organism. Seven pneumonias were caused by organisms not frequently pathogenic to man (flavobacteria, serratia and Streptococcus faecalis). The mortality rate for acquired pneumonia in this study, 64 per cent, is greater than that in previous studies in which either no polymyxin or cyclic polymyxin therapy was used. Continuous use of polymyxin B aerosol appears to be a dangerous form of therapy.

Aerosols↗
PubMed1975

Cellular and regional localization of pentobarbital-2-14C by radioautography of selected areas of mouse brain at loss and return of withdrawal response.

Regional and cellular distribution of pentobarbital-14C in mouse brain was determined by frozen-section radioautographic methods. The mice were studied at the times of loss (WRL) and return (WRR) of withdrawal response following a single intravenous dose of either 40 or 50 mg/kg body weight. At WRL, grey matter areas had higher concentrations of pentobarbital-2-14C than white matter. At WRR grey matter concentrations were not altered, but white matter areas were now similar to the grey. At WRL pentobarbital concentration was 55 per cent higher in large pyramidal cells in the parietal cortex than in surrounding neuropil. At WRL hippocampal pyramidal cell bodies (stratum pyramidalis) and glial cells in corpus callosum had pentobarbital levels similar to that of surrounding neuropil. Levels in the neuropil of these three areas were higher at WRR than at WRL. Lipid-rich compartments had higher pentobarbital concentrations at WRR than at WRL. The results suggest that return of consciousness after pentobarbital anesthesia is associated with intracerebral redistribution of pentobarbital even while there is continuing uptake into brain. (Key words: Brain, pentobarbital uptake; hypnotics, barbiturates, pentobarbital; pharmacokinetics, pentobarbital uptake.).

Absorptiometry, Photon↗