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Biomedical subjects

B R Hecker

Publications and source records attributed to B R Hecker.

12 recordsLinked to original sources
PubMed1989

A comparison of two pulmonary artery mixed venous oxygen saturation catheters during the changing conditions of cardiac surgery.

Continuous mixed venous oxygen saturation (SvO2), using modified pulmonary artery (PA) catheters, can assist in the management of cardiac surgery patients. Two FDA-approved catheters are available for SvO2 monitoring. One system uses two wavelengths of light and the other is a three-wavelength system. The present study was designed to determine the accuracy of the two catheters during cardiac surgery. Sixty-five consecutive patients were assigned to one of the two catheter groups. Data were collected pre- and post-induction, after sternotomy, and after extracorporeal circulation. An updated hematocrit was entered in the two-wavelength system preceding the last two measurements. Patient demographics, severity of preoperative cardiac disease, and intraoperative hemodynamics were comparable between groups. Two-wavelength determinations varied inconsistently from cooximeter values, while three-wavelength measurements did not differ significantly. Changes in hematocrit were responsible in part for the variability in two-wavelength measurements. In summary, three-wavelength measurements by the Shaw system were more accurate than two-wavelength measurements by the Edwards system.

Aged↗
PubMed1989

Effect of intercostal nerve blockade on respiratory mechanics and CO2 chemosensitivity at rest and exercise.

Lower intercostal and abdominal muscles interact with other respiratory muscles to produce inspiration as well as expiration. Intercostal nerve blockade from T6-T12 was produced in seven healthy males to study its effect on: 1) supine pulmonary function, 2) inspiratory effort, 3) hypercapnic ventilatory response, including mouth occlusion pressures with and without an expiratory load, and 4) ventilation during progressive exercise on a cycle ergometer. Studies during control and blocked states were performed on different days. Lower chest and abdominal wall paralysis was documented with electromyography. Findings include a minimal decrease in peak expiratory flows with intercostal blockade (P = 0.02), but no other changes in supine resting pulmonary function tests, inspiratory effort, or hypercapnic ventilatory response slopes. Minute ventilation, respiratory rate, and VT/TI during exercise were also minimally increased, indicating an increase in the drive to breathe, which was unrelated to a change in metabolic rate. During exercise, total time to exhaustion was decreased following intercostal nerve blockade. Bilateral intercostal nerve blockade produced minimal decreases in peak expiratory flow at rest in supine subjects. During seated exercise, there was a slight increase in respiratory drive, probably due to minor alterations in the mechanics of breathing induced by intercostal blockade. The authors conclude that, in healthy young subjects, intercostal nerve blockade does not exert a clinically significant adverse affect on pulmonary mechanics and that ventilatory function is well-maintained even at extremes of ventilatory demand.

Adult↗
PubMed1987

Pulmonary oedema following airway obstruction in a patient with Hodgkin's disease.

We report a case of pulmonary oedema following airway obstruction in a patient who underwent biopsy of a tumour involving the anterior mediastinum and neck. The occurrence of airway obstruction in patients with anterior mediastinal masses, and the pathogenesis of pulmonary oedema occurring in association with airway obstruction, are discussed.

Adult↗
PubMed1985

Influence of magnesium ion on human ventricular defibrillation after aortocoronary bypass surgery.

The administration of magnesium ion (Mg++) has been reported to defibrillate the ventricles and to decrease the incidence of arrhythmias after cardiopulmonary bypass. In a prospective study of 76 randomly selected patients undergoing coronary artery bypass grafting, patients received either no Mg++, 0.25 mEq/kg of Mg++ during cardiopulmonary bypass with the aorta clamped, or 0.375 mEq/kg of Mg++ before cardiopulmonary bypass. Spontaneous resumption of a cardiac rhythm or spontaneous defibrillation during reperfusion was not significantly affected by Mg++ administration. However, the number of shocks to initial and to sustained defibrillation and the energy required for the last direct-current shock was greatest in patients who received Mg++ before bypass and in those whose plasma Mg++ was greater than 2.26 mg/dl. Thus, the administration of Mg++ may have adverse effects on the heart if intraoperative plasma Mg++ exceeds 2.26 mg/dl.

Cardiopulmonary Bypass↗
PubMed1985

Analgetic contribution of sufentanil during halothane anesthesia: a mechanism involving serotonin.

Catecholamine and serotonin concentrations in the cord, medulla, and hypothalamus were measured in rats after saline, after sufentanil sufficient to reduce the minimum alveolar concentration (MAC) of halothane by 30% or less, or after sufentanil sufficient to reduce the MAC of halothane by 80% or more. In the cord, high doses of sufentanil resulted in a 13.4% reduction (P less than 0.05) in serotonin concentration compared to saline control and a 17.4% reduction (P less than 0.05) in serotonin concentration compared to low dosages of sufentanil. A 12.8% reduction (P less than 0.05) in medullary serotonin also was observed with high sufentanil compared to low sufentanil. Epinephrine decreased significantly in the hypothalamus at the high sufentanil dose. No other significant differences were found in catecholamine content. The experimental results support the hypothesis that sufentanil may contribute to an analgetic component of general anesthesia by modulating nociception via the release of 5-HT.

Analgesics↗
PubMed1983

Intraoperative diagnosis and treatment of massive pulmonary embolism complicating surgery on the abdominal aorta.

Massive pulmonary embolism associated with total cardiovascular collapse occurred during the surgical repair of a ruptured abdominal aortic aneurysm with an aortocaval fistula. Pulmonary artery pressure monitoring permitted immediate diagnosis whereas central venous pressures did not reflect the obstruction to right ventricular outflow. Pulmonary embolectomy without cardiopulmonary bypass was performed successfully.

Aorta, Abdominal↗
PubMed1983

The decrease of the minimum alveolar anesthetic concentration produced by sufentanil in rats.

The anesthetic potency of sufentanil was established by determining its effect on the minimal alveolar anesthetic concentration (MAC) of halothane. Each of eight selected doses of sufentanil was administered to a group of four to five mechanically ventilated rats anesthetized with halothane. Sufentanil was administered as a constant infusion preceded by an intravenous bolus dose that was three times that of the infusion rate per minute. The tail-clamp technique was used to establish control MAC and the MAC of halothane with sufentanil. Increasing sufentanil dosages were nonlinearly related to reductions in the MAC of halothane. A sigmoidal dose-response curve was described. An abrupt, steep response follows the initial upward deflection of the curve with an additional 62% MAC reduction occurring between doses of 1 X 10(-5) mg X kg-1 X min-1 and 1 X 10(-4) mg X kg-1 X min-1. Essentially complete anesthesia was seen at the latter dosage. No significant adverse side effects were seen with sufentanil at doses up to 1 X 10(-2) mg X kg-1 X min-1.

Anesthesia, Inhalation↗
PubMed1977

Psychosocial function in women treated for vaginal agenesis.

The psychosocial functioning of 23 women treated both surgically and nonsurgically for vaginal agenesis was assessed by means of a retrospective questionnaire. Subjects were also physically examined to evaluate anatomic outcome. It was concluded that the patients psychological adjustment before treatment and the sensitivity of her family and medical advisors during treatment took precedence over anatomic results in the eventual resolution of this disorder. Sexual function, emotional stability, self-image, and choice of marital partner in these women are described in some detail and are, in general, far healthier than had been depicted in earlier psychological reports.

Adaptation, Psychological↗