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Biomedical subjects

J L Hoyt

Publications and source records attributed to J L Hoyt.

13 recordsLinked to original sources
PubMed2000

Fortified sera and their use in environmental virology.

Four commercially available fortified sera were compared to fetal bovine serum (FBS) with regard to their ability to maintain or increase the sensitivity of the Buffalo green monkey (BGM) kidney cell line to viral infection. Nine virus strains and five wastewater samples were used. Fortified sera were comparable to FBS for the enumeration of some viruses by the plaque method and for the detection of virus in wastewater by the most-probable-number assay.

Animals↗
PubMed1979

Comparison of hemodynamic, pulmonary, and renal effects of use of three types of fluids after major surgical procedures on the abdominal aorta.

Hemodynamic, pulmonary, and renal variables were measured in 24 patients scheduled for major abdominal aortic operations. Control values were obtained before preoperative medications were given. All patients received 5% dextrose in Lactated Ringer's solution intraoperatively. Postoperatively, group 1 patients received 5% dextrose in water plus albumin, group 2 received 5% dextrose in 0.45 sodium chloride solution, and group 3 received 5% dextrose in lactated Ringer's solution. There were significant increases in Qs/Qt and AaDO2, 48 hours after operation in group 3. Oxygen consumption and cardiac output increased in all groups 24 hours after operation. Twenty-four hours later, these two variables returned to control values in group 1 but continued to rise in the other two groups. Significant diuresis occurred in group 1, 48 hours postoperatively, whereas the other two groups continued to retain water. Use of albumin and 5% dextrose in water in the postoperative period seemed to produce less deviations from control values of most measured variables, than the other two groups.

Albumins↗
PubMed1976

Cardiovascular and respiratory changes in response to change of posture in the very obese.

Circulatory and respiratory effects of change of posture from sitting to supine were studied in 11 obese patients scheduled for gastric bypass operations. Patients were studied on the morning of operation before any medication was given. Average weight was 138.8 kg, 108.6 per cent above ideal weight. Change of posture from sitting to supine was associated with 11 per cent increase in oxygen consumption (VO2), 35.5 per cent increase in cardiac output (CO), 35.8 per cent increase in cardiac index, 17.85 per cent decrease in arteriovenous oxygen difference, 31 per cent increase in mean pulmonary arterial pressure, 44 per cent increase in pulmonary-artery wedge pressure, 21.5 per cent decrease in peripheral resistance (PR), 6 per cent decrease in heart rate, and 17.7 per cent increase in venous admixture (QS/Qt). All these changes were significant. There was no change in mean arterial pressure, alveolo-arterial O2 difference and respiratory rate. The increase in CO was attributed to reduction in PR and to increased V02 probably due to increased work of breathing.

Adult↗
PubMed1975

A method for measuring oxygen consumption and cardiac output in intensive care units.

A simplified measurement of oxygen consumption was investigated in 15 spontaneously ventilating and 11 apnoeic patients in the intensive care unit following open-heart surgery, using a Godart Pulmonet type 11e. Three consecutive measurements were performed on each patient to define the reproducibility of the method. The coefficient of variation of VO2 was plus or minus 3.16 per cent and plus or minus 3.42 per cent in spontaneously breathing and apnoeic patients respectively. Arterio-mixed venous oxygen difference (CaO2-CVO2) was also measured and cardiac output (CO) calculated using the Fick principle, in the spontaneously ventilating patients. Coefficient of variation of CaO2-CVO2 and CO values were plus or minus 4.63 per cent and plus or minus 4.70 per cent respectively.

Arteries↗
PubMedDate not supplied

Management of carbon monoxide poisoning in the absence of hyperbaric oxygenation chamber.

Manifestations of carbon monoxide poisoning are mostly attributable to acute hypoxic insult. In the absence of immediately available hyperbaric oxygen chamber, 100% oxygen should be delivered to the patient until carboxyhemoglobin levels in the blood are less than 5%. Presence of abnormal motor activity or prolonged abnormal consciousness are indications for proceeding with hypothermia and mechanical ventilation. Reversal of these manifestations was achieved in 3 reported cases though induction of hypothermia was delayed for as long as 24 hours. However, no beneficial effects were obtained in a fourth patient who did not receive hypothermia until 5 days after exposure. The duration of hypothermia varied between 60-70 hours in patients who showed near-complete recovery.

Carbon Monoxide Poisoning↗
PubMedDate not supplied

Algorithm for management of pulmonary complications in burn patients.

An algorithm for management of pulmonary complications in burn patients on the same basis as in patients with adult respiratory distress syndrome is outline. Pao2 of less than 60 torr (F(I)O2 0.21-0.4, PaCO2 over 40 torr, pH less than 7.35, respiratory rate over 40/min, and clinical evidence of compromised upper airway were the indications for initation of aggressive intensive respiratory care. This consisted of nasotracheal intubation, arterial cannulation, pulmonary artery catheterization, and establishment of mechanical ventilation. The algorithm further defines the subsequent management of these patients as far as need for continued mechanical ventilation, fluid and electrolyte balance, hemodynamic stability, and renal function.

Burns↗
PubMedDate not supplied

An evaluation of hypocarbia and hypercarbia during carotid endarterectomy.

One hundred consecutive patients were randomly given hypocarbic (PaCO2 less than 25 torr) or hypercarbic (PaCO2 greater than 60 torr) general anesthesia during carotid endarterectomy to test the effect of the two regimens upon the incidence of postoperative neurological deficit. An indwelling shunt was not used. One patient died, two have permanent neurological deficits and two have temporary neurological deficits. Although hypocarbic patients had fewer neurological complications than hypercarbic patients, the difference was not statistically significant (p less than 0.13). Hypercarbia significantly increased the incidence of intraoperative arrhythmia. Also, no relationship was found between the incidence of postoperative stroke and the internal carotid back pressure or the time of carotid occlusion.

Anesthesia, General↗
PubMedDate not supplied

Heparin dose for accurate anticoagulation in cardiac surgery.

A simplified technique relating individual heparin dose to desired anticoagulant effect was used in 152 patients during cardiac surgery. Activated clotting time (act) was measured by semi-automated technique (Hemochron) before and after heparin, 200 U/kg I.V. Two point linear dose-response curve allowed calculation of any additional heparin required for uniform ACT of 480 seconds. Mean heparin requirement was 330 U/kg) (range 200--600 U/kg) mean requirements for adults (mean = 310 U/kg) were significantly less (p less than 0.001) than for children (mean = 430 U/kg). Individual dose-response curves suggested 20 patients (13%) could have been below adequate anticoagulant levels (ACT less than 300 seconds) using our previous formula for heparin dosage (9000 U/m2). At completion of cardiopulmonary bypass, measurement of ACT provided circulating heparin level from the dose-response curve. Protamine dose (1.3 mg/100 U. heparin) was individualized to precisely reverse anticoagulant effect to control ACT in 127 of 152 patients (84%) with a single dose. Elimination of patient and product variability by simplified semi-automated dose-response technique for heparin therapy provides uniform anticoagulant effect and its accurate neutralization. This technique is recommended for precise anticoagulant therapy during open heart surgery.

Adolescent↗