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Biomedical subjects

T W Feeley

Publications and source records attributed to T W Feeley.

At least 37 records · Page 2Linked to original sources
PubMed1986

The thermal-dye method of lung water measurement is reliable at a low cardiac output.

The measurement of lung water by the thermal-dye double indicator dilution technique was evaluated in dogs with normal and edematous lungs during a state of reduced cardiac output. The technique used cold indocyanine green dye to measure extravascular thermal volume (EVTV) as an estimate of extravascular lung water (EVLW). Anesthesia was maintained with pentobarbital. In 15 of 21 animals, pulmonary edema was first induced with oleic acid (0.75 to 0.18 ml/kg). Cardiac output (CO) was then decreased by a combination of propranolol and slow exsanguination (mean CO reduction to 36% of baseline). Extravascular lung water produced in this model ranged from 1.4 to 30.2 ml/kg. Predetermination measurements of EVTV correlated closely with EVLW as determined by gravimetric analysis (EVTV = 1.1 EVLW + 4.7 ml/kg, n = 21, r = 0.93, P less than 0.001). Thermodilution cardiac output measured in the abdominal aorta (used in the calculation of the EVTV) correlated well with simultaneous measurements of cardiac output by both indocyanine green dye dilution and pulmonary artery thermodilution (r = 0.86 and r = 0.88, respectively, pretermination). The thermal-dye technique appears to provide an accurate reflection of lung water in normal and edematous lungs, even in the presence of a low cardiac output.

Animals↗
PubMed1986

Hypothermic preservation of the heart and lungs with Collins solution: effect on cardiorespiratory function following heart-lung allotransplantation in dogs.

The effect of preserving the heart and lungs with hypothermia and Collins solution was studied in 13 mongrel dogs undergoing combined heart-lung transplantation. The five control animals who underwent an immediate transplant following Collins solution perfusion had small increases in extravascular lung water when measured 2.5 hours posttransplant as seen in a previous study. The eight animals who had hypothermic preservation following Collins solution perfusion had significantly higher extravascular lung water than controls (16.3 +/- 1.8 ml/kg in preserved animals; 11.2 +/- 1.7 ml/kg in controls p less than 0.05). The level of lung water reached at 2.5 hours postoperatively was similar to that reached with a previously reported, unacceptable preservation technique. Survival beyond this point was poor due to severe pulmonary edema. We conclude that the use of this solution, given under the experimental conditions which we describe, is not acceptable for hypothermic preservation of the heart and lungs for combined transplantation.

Animals↗
PubMed1985

The effect of hypothermic preservation of the heart and lungs on cardiorespiratory function following canine heart-lung transplantation.

The effect of hypothermic preservation of the heart and lungs with a crystalloid solution was evaluated in 12 mongrel dogs receiving heart-lung allografts. Six animals served as controls and received an immediate heart-lung transplant. Six animals were in the experimental group and received a heart-lung transplant after 5 hours of preservation at 4 degrees C following perfusion of both organs with a crystalloid solution. Physiological function of the heart and lungs was studied for 20 hours after transplantation. While cardiac function was minimally depressed following preservation, pulmonary function testing demonstrated significantly greater increases in extravascular lung water in experimental animals, suggesting that an ischemic lung injury occurred with this preservation technique. The model allows for future evaluation of other methods of combined preservation of both the heart and lungs for transplantation.

Airway Resistance↗
PubMed1985

Failure of the colloid oncotic-pulmonary artery wedge pressure gradient to predict changes in extravascular lung water.

Colloid oncotic pressure (COP), pulmonary artery wedge pressure (WP), and the COP-WP gradient were measured in seven critically ill adult patients and compared with extravascular lung water determined using the thermal-dye double-indicator dilution technique and a bedside lung water computer. Correlation coefficients for changes in extravascular lung water vs. COP, WP, and COP-WP were not significant, and in this patient population the COP-WP gradient did not predict changes in extravascular lung water.

Adult↗
PubMed1985

Evaluation of the portable chest roentgenogram for quantitating extravascular lung water in critically ill adults.

The diagnosis of pulmonary edema is frequently made from characteristic findings on the chest roentgenogram that suggest an increase in lung water. Optimal radiographic technique depends on a cooperative upright patient, which is not possible with most critically ill patients. These patients may also have multiple radiographic abnormalities that make interpretation of the chest roentgenogram difficult. The ability of portable chest roentgenograms to accurately identify the presence of excess lung water and monitor changes in lung water has not previously been evaluated in critically ill adults who are intubated and ventilated and in the supine position when the films are exposed. In 12 patients the pulmonary edema seen on portable chest roentgenograms was given a score (0 to 390 points), which was then compared with a determination of extravascular lung water using the thermal-dye indicator dilution technique. A linear correlation was observed (r = 0.51; p less than 0.05; n = 73). Evaluation of a change in radiographic score vs a change in lung water showed no linear correlation (r = 0.1; p greater than 0.05). While portable chest roentgenograms exposed under the conditions described were a useful technique for demonstrating pulmonary edema, they were not accurate in monitoring modest changes in lung water in critically ill patients.

Adult↗
PubMed1984

Monitoring end-tidal carbon dioxide tensions with high-frequency jet ventilation in dogs with normal lungs.

The end-tidal carbon dioxide tension (PetCO2) measured after a single, large tidal-volume breath (15 ml/kg body weight) was compared to simultaneous measurements of PaCO2 in 6 dogs with normal lungs who were receiving high-frequency jet ventilation (HFJV). There was an excellent linear correlation between PetCO2 and the PaCO2 over the entire range of CO2 tensions commonly encountered in clinical practice (PetCO2 = 0.9 PaCO2 + 2.2 torr; n = 51, r = .98, p less than .001, range of PaCO2 = 12-72 torr). We conclude that when lung function is normal, a simple system of measuring PetCO2 after a large breath is an accurate method of monitoring the effectiveness of CO2 elimination during HFJV.

Animals↗
PubMed1982

Measurement of extravascular lung water in dogs using the thermal-green dye indicator dilution method.

The measurement of extravascular lung water by a double-indicator dilution technique using cold indocyanine green dye was evaluated in dogs. Pulmonary edema was induced in 11 animals by volume overload; 12 animals served as controls. For each measurement, the two indicators (cold dye) were injected into the superior vena cava and detected in the femoral artery. The extravascular thermal volume was calculated using the mean transit times of the two indicator curves. Pretermination measurements of extravascular thermal volume correlated closely with standard gravimetric analysis of pulmonary extravascular tissue weight (EVTV - 1.15 PEW + 2.1 ml/kg, n = 21, r = 0.97, P less than 0.001; where EVTV = extravascular thermal volume and PEW = pulmonary extravascular tissue weight). Throughout the experiment, the arterial oxygen tension and alveolar-arterial oxygen tension gradient, correlated poorly with EVTV (linear correlation: r = 0.47, 0.45, respectively). The intrapulmonary shunt correlated better with EVTV (r = 0.72). Nonlinear correlation of EVTV with intravascular pressures (left ventricular filling pressures, colloid oncotic pressures, and the pulmonary artery occlusion pressure-colloid oncotic pressure gradient) were more significant than linear relationships. The critical pressures at which lung water rapidly increased in this model occurred at left ventricular filling pressures of 22-27 mmHg and at pulmonary artery occlusion pressure-colloid oncotic pressure gradients of 25-30 mmHg. The thermal dye technique appears to provide an accurate measurement of lung water changes in this pressure edema model.

Animals↗
PubMed1982

Effect of graded administration of PEEP on lung water in noncardiogenic pulmonary edema.

The effect of graded application of positive end-expiratory pressure (PEEP) was studied in 10 mongrel dogs with pulmonary edema induced by oleic acid infusion. Six animals received progressive increases in PEEP (5 cm H2O) 120 min after the injection of oleic acid. These animals were compared to 4 control animals who did not receive PEEP. We found no difference between the 2 groups in lung water measured by a double indicator dilution technique during PEEP application. Lung water determined by gravimetric analysis was also not different between groups at the end of the experiment. PEEP did result in significant reductions in shunt fraction and alveolar-arterial oxygen tension difference suggesting that PEEP improves gas exchange in pulmonary edema by increasing lung volume, but not by altering lung water accumulation.

Animals↗
PubMed1981

Sterile anesthesia breathing circuits do not prevent postoperative pulmonary infection.

In a prospective, randomized trial, the effectiveness of sterile anesthesia breathing circuits having bacterial filters in decreasing the incidence of postoperative pulmonary infection was evaluated. Two hundred ninety-three patients undergoing major surgical procedures were assigned randomly to receive anesthetics through a sterile, disposable circuit having a bacterial filter, or a reusable circuit that had been washed and dried after previous use. The two groups were well matched for age, sex, type of surgical procedure, type of anesthetic, and history of smoking or obstructive lung disease. A physician observer, who was unaware of these assignments, reviewed the patients' post-operative status for evidence of pulmonary infection. The over-all rate of infection was 3.5 per cent; no significant difference in the rates of infection occurred between the two groups. Five (3.6 per cent) of the 138 patients anesthetized with sterile circuits had postoperative respiratory infection, compared with four (2.6 per cent) of the 155 patients anesthetized with unsterile circuits. In both groups, maximum postoperative temperature, white-blood-cell count, and the lowest values for arterial oxygen tension were similar. The authors therefore conclude that when simple hygienic measures are followed, the routine use of sterile anesthesia breathing circuits with bacterial filters does not decrease the risk of postoperative infection.

Anesthesia, Inhalation↗
PubMed1980

Changes in venous admixture with alterations of inspired oxygen concentration.

To assess the change in venous admixture during breathing of 100 per cent oxygen (FIO2 1.0), shunt fraction (Qs/Qt) was calculated at a maintenance FIO2 (FIO2m:0.27--0.70) and at FIO2 1.0 in 40 studies of 34 patients with acute respiratory failure. At FIO2 1.0 Qs/Qt increased in 26 studies, but did not increase in 14 studies. Patients in whom Qs/Qt increased during breathing of oxygen and mild respiratory failure, as indicated by low Qs/Qt values at FI02m and a low incidence of diffuse parenchymal infiltrates on chest roentgenograms. All patients who had recently had cardiovascular surgical procedures were in this group. Respiratory failure was more severe in those in whom Qs/Qt decreased with oxygen, as indicated by high Qs/Qt values at FIO2m, evidence of diffuse pulmonary disease by roentgenography, and signs of adult respiratory distress syndrome. The authors conclude that changes in Qs/Qt in response to FIO2 1.0 in acute respiratory failure are related to the severity of respiratory insufficiency.

Acute Disease↗
PubMed1980

The lack of effect of variable blood withdrawal rates on the measurement of mixed venous oxygen saturation.

In a study of 12 critically ill patients, values for mixed venous oxygen saturation (SVO2) were measured from samples of pulmonary arterial blood drawn at five rates of withdrawal (1, 3, 10, 20, and 30 ml/min). Samples were drawn from properly placed pulmonary arterial catheters with the balloon deflated. Physiologic stability was documented at the beginning and end of the sampling period in all but one patient. Results in each patient demonstrated a close grouping of values for SVO2 obtained at the five rates of withdrawal (largest standard deviation, 1.9 percent). Evaluations by paired t-test comparing all rates of withdrawal with the slowest rate (1 ml/min) showed no significant differences. The rate of withdrawal of the sample is not associated with significant errors in SVO2 when samples are drawn from a properly positioned pulmonary arterial catheter.

Adult↗
PubMed1980

Postoperative respiratory care: a controlled trial of early and late extubation following coronary-artery bypass grafting.

Sequelae of early versus late extubation of the trachea in patients following coronary-artery bypass grafting were compared prospectively in 38 patients randomly assigned to one of the two groups. The times to extubation were 2 +/- 2 and 18 +/- 3 hours after operation for the two groups. Comparisons were made between groups for the following five variables: time spent in the intensive care unit; drug utilization in the intensive care unit; cardiopulmonary morbidity; hemodynamic performance; patient stress (plasma norepinephrine levels). The anesthetic technique consisted of induction with thiopental, nitrous oxide, and halothane, followed by maintenance with nitrous oxide and halothane. Pancuronium was the only muscle relaxant administered. Patients whose tracheas were extubated early had muscle relaxants reversed prior to the application of extubation criteria. There was no significant difference between the groups in times spent in the intensive care unit, hemodynamic performances, or plasma norepinephrine levels; however, the patients whose tracheas were extubated early received less morphine and diazepam and suffered significantly less cardiopulmonary morbidity.

Aged↗
PubMed1978

Pancuronium bromide.

Pancuronium bromide is a nondepolarizing muscle relaxant approved to induce skeletal muscle relaxation during anesthesia and to facilitate the management of patients undergoing mechanical ventilation. The use of pancuronium bromide during surgery led to the appreciation that it has advantages over drugs previously used for muscle relaxation. Patients in whom pancuronium bromide is of value are (1) hypoxemic patients resisting mechanical ventilation and so cardiovascularly unstable that use of sedatives is precluded, (2) patients with bronchospasm unresponsive to conventional therapy, (3) patients with severe tetanus or poisoning where muscle spasm prohibits adequate ventilation, (4) patients with status epilepticus unable to maintain their own ventilation, (5) shivering patients in whom metabolic demands for oxygen should be reduced, and (6) patients requiring tracheal intubation in whom succinylcholine administration is contraindicated. Without concomitant sedation, use of pancuronium bromide is associated with psychological risks. Other risks are undetected ventilator disconnection, tachyarrythmias, prolonged paralysis and drug interactions.

Animals↗
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↗