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Biomedical subjects

B C Leiman

Publications and source records attributed to B C Leiman.

At least 19 recordsLinked to original sources
PubMed1989

The effects of oral transmucosal fentanyl citrate premedication on preoperative behavioral responses and gastric volume and acidity in children.

The authors compared the safety, efficacy, and effects on gastric volume and pH of oral transmucosal fentanyl citrate (OTFC) premedication and of placebo lollipop and no premedication in 55 children undergoing elective operations. The patients were randomly assigned to receive no premedication (group A, N = 18); OTFC containing 15-20 micrograms/kg of fentanyl citrate (group B, N = 18); or a placebo lollipop (group C, N = 19). Activity (sedation) and anxiety scores, vital signs (including systolic and diastolic arterial blood pressures, heart and respiratory rates), and pulse oximetry determined oxygen saturation were measured before and at 10-min intervals after premedication until the patients were taken to the operating room. Gastric contents were aspirated via an orogastric tube and analyzed for volume and pH after induction of anesthesia. Quality of induction and recovery were evaluated using scoring schedules; recovery times were measured and side effects recorded. OTFC was readily accepted and provided levels of sedation and anxiolysis significantly greater after 10 min than after no premedication or the placebo lollipop. Arterial blood pressures, heart rate, and oxygen saturations were not different among the three groups. In patients given OTFC, respiratory rates were significantly lower after 10 min than they were in patients having no premedication.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1988

Effect of the Trendelenburg position on the distribution of arterial air emboli in dogs.

We examined the effects of buoyancy on the distribution of arterial gas bubbles using in vitro and in vivo techniques in dogs. A simulated carotid artery preparation was used to determine the effects of bubble size and vessel angle on the velocity and direction of bubble movement in flowing blood. Because buoyancy tends to float bubbles away from dependent areas, bubble velocity would be expected to decrease as the vessel angle increased. We found that larger bubbles increased in velocity in the same direction as the blood flow at 0-, 10-, and 30-degree vessel angles and decreased when the vessel was positioned at 90 degrees. Smaller bubbles did not change velocity from 0 to 30 degrees and increased in velocity in the same direction as blood flow at 90 degrees. In 10 anesthetized dogs, we studied the effects of 0-, 10-, 15-, and 30-degree Trendelenburg's position on carotid artery distribution of gas bubbles injected into the left ventricle or ascending aorta. Regardless of the degree of the Trendelenburg position, the bubbles passed into the carotid artery simultaneously with passage into the abdominal aorta. We conclude that the forces of buoyancy do not overcome the force of arterial blood flow and that the Trendelenburg position does not prevent arterial bubbles from reaching the brain.

Animals↗
PubMed1988

Effects of inhalation anaesthetics on filtration of venous gas emboli by the pulmonary vasculature.

Venous gas emboli are prevented from reaching the systemic circulation by filtration in the pulmonary vasculature. This filtration can be overwhelmed by exceeding certain critical rates of venous air infusion. To characterize further these filtration phenomena, the effects of pentobarbitone, isoflurane and halothane anaesthesia on the incidence of spillover of venous bubbles into the arteries were studied in groups of nine dogs. Venous air was infused at rates of 0.25, 0.30, and 0.35 ml kg-1 min-1. Spillover of venous bubbles into the arteries was detected with a Doppler ultrasonic probe located over the suprarenal aorta. At the lowest venous air dose (0.25 ml kg-1 min-1), no bubbles were detected in the systemic circulation in the pentobarbitone- or halothane-anaesthetized dogs, while arterial bubbles were detected in two with isoflurane anaesthesia. At 0.30 ml kg-1 min-1 air, one, four and two dogs had arterial bubbles detected with pentobarbitone, halothane or isoflurane anaesthesia, respectively, while at 0.35 ml kg-1 min-1 spillover of bubbles occurred in four, five and three, respectively. The spillover of venous bubbles into the arteries was dose-related for the pentobarbitone- and halothane-anaesthetized dogs.

Anesthesia, Inhalation↗
PubMed1988

A comparison of different methods of lubrication of glass syringes used to identify the epidural space.

Measurement of loss of resistance in glass syringes is a method widely used to locate the epidural space in epidural anaesthesia. Static and dynamic forces were measured under four experimental conditions in new glass syringes: unpolished, dry; polished, dry; unpolished, saline lubricated; and polished, saline lubricated. The unpolished saline lubricated syringes had a mean (SD) static force of 53.18 (15.0) g and dynamic force of 40.88 (15.2) g. These values were significantly greater than for polished dry syringes where the values were 5.27 (2.1) g and 4.38 (0.94) g, respectively. The results show that the least amount of resistance to plunger movement is obtained by dry polishing glass syringes.

Anesthesia, Epidural↗
PubMed1987

Arterial air embolism of venous origin in dogs: effect of nitrous oxide in combination with halothane and pentobarbitone.

The effects of using nitrous oxide (N2O) with halothane or pentobarbitone anaesthesia on the filtration of venous air emboli (VAE) by the pulmonary circulation were studied in dogs. Dogs anaesthetized with either pentobarbitone, pentobarbitone/N2O, halothane, or halothane/N2O were embolized with venous air into the right atrium at 0.25 to 0.35 ml.kg-1.min-1 for 30 min. The animals were in a supine, head down position. A Doppler ultrasonic probe located over the suprarenal aorta detected arterial bubbles that escaped filtration by the lungs. No bubbles were detected at 0.25 ml.kg-1.min-1, but at 0.30 ml.kg-1.min-1 the incidence was 11 per cent (pentobarbitone), 0 per cent (pentobarbitone/N2O), 33 per cent (halothane), and 63 per cent (halothane/N2O) and at 0.35 ml.kg-1.min-1, 44 per cent (pentobarbitone), 14 per cent (pentobarbitone/N2O), and 56 per cent (halothane). Half of the dogs receiving VAE with halothane/N2O at 0.30 ml.kg-1.min-1 died within the first 10 min of the air infusion. Thus, no animals were studied at the next higher dose (0.35 ml.kg-1.min-1). The results suggest that the occurrence of VAE with nitrous oxide anaesthesia may result in greater haemodynamic consequence and increased likelihood for spillover of the venous bubbles into the arteries if used with halothane as compared to pentobarbitone.

Anesthesia, Inhalation↗
PubMed1987

Removal of tracheal secretions in anesthetized dogs: balloon catheters versus suction.

Artificial secretions were removed by suction (using 12- or 18-French suction catheters) or by means of a balloon-tipped catheter (6-French Fogarty arterial embolectomy catheter) in 20 experiments performed on five dogs anesthetized with halothane. Each dog had 5 ml of mucin injected 10 cm down the endotracheal tube prior to a 30-sec period of intermittent positive pressure ventilation. After this procedure, the ventilator was disconnected and the secretions were removed by suction with the 12- or 18-French catheters or by the Fogarty catheter. Each dog had balloon removal performed twice and suction performed once with the 12-French and once with the 18-French catheter. The endotracheal tube was cleaned and a 15-min stabilization period was allowed between each experiment. Arterial blood pressure (MAP) and pulmonary artery pressure (PAP) did not change after either technique. There were no ECG changes, arrhythmias, or alterations in PaCO2. The PaO2 was significantly lower in the two suction catheter groups [520 +/- 33 mm Hg (12 French) and 451 +/- 31 mm Hg (18 French)] than in the balloon removal group (564 +/- 10 mm Hg) (P less than 0.05). The balloon technique removed more secretions (4.52 +/- 0.06 ml) than did suction (12 French, 1.32 +/- 0.17 ml; 18 French, 2.11 +/- 0.44 ml). Balloon removal of tracheal secretions has two advantages over conventional suction techniques: it removes more secretions, and it has less detrimental effect on arterial oxygenation.

Anesthesia, Endotracheal↗
PubMed1987

Mechanisms of succinylcholine-induced arrhythmias in hypoxic or hypoxic:hypercarbic dogs.

To evaluate the effects of succinylcholine on cardiac arrhythmias and serum levels of potassium and catecholamines, dogs with hypoxia alone and with hypoxia and hypercarbia were studied during anesthesia with halothane or enflurane. After the injection of succinylcholine (0.3 mg/kg), cardiac arrhythmias occurred in all halothane:hypoxia dogs and in 70% of dogs given halothane during hypoxia:hypercarbia. No dogs given enflurane anesthesia developed arrhythmias. Serum potassium levels increased significantly 3 and 5 min after succinylcholine in all groups. Serum epinephrine levels increased in the halothane-hypoxia:hypercarbia and enflurane:hypoxia groups and, after the injection of succinylcholine, epinephrine levels increased further in dogs in the halothane:control, halothane:hypoxia, halothane-hypoxia:hypercarbia, enflurane:hypoxia, and enflurane-hypoxia:hypercarbia groups. Norepinephrine levels increased with enflurane-hypoxia:hypercarbia and after the succinylcholine in the halothane:hypoxia, halothane-hypoxia:hypercarbia, and enflurane-hypoxia:hypercarbia groups. The results suggest that succinylcholine induces arrhythmias by sympathetic stimulation and that halothane sensitizes the myocardium to arrhythmias at the same levels of serum catecholamines and potassium in the presence of hypoxia or hypoxia:hypercarbia more than does enflurane.

Anesthesia, Inhalation↗
PubMed1986

Neurolept anaesthesia using etomidate as the hypnotic agent.

A technique of neurolept anaesthesia using etomidate (Hypnomidate; Janssen) instead of nitrous oxide is described in which a continuous infusion of 1 mg/kg/h is used to supplement droperidol, fentanyl and alcuronium. This totally intravenous technique eliminates theatre pollution, may offer haemodynamic stability and may be of use in patients with raised intracranial pressure. Pain on injection and muscle movements which occur with etomidate administration do not detract from the value of this technique.

Adolescent↗
PubMed1986

Etomidate infusion for resection of phaeochromocytoma. A report of 2 cases.

Anaesthesia in patients undergoing resection of phaeochromocytomas is associated with fluctuations in blood pressure and cardiac dysrhythmias. Two patients in whom an etomidate (Hypnomidate; Janssen Pharmaceutica) infusion was used as a supplement to droperidol, fentanyl, pancuronium, air and oxygen anaesthesia are described. Cardiovascular stability was well maintained; the advantages of this technique are discussed.

Adult↗
PubMed1986

Anaesthesia for the achondroplastic dwarf.

Over the past three years, 36 anaesthetics were administered to 27 patients with achondroplastic dwarfism. Twenty-four patients underwent craniectomy for foramen magnum stenosis. Sixteen of the operations were undertaken in the sitting position with nine incidents of venous air embolism (VAE), all of which occurred in patients under 12 years of age. Six major complications occurred: two C-1 level spinal cord infarctions, two brachial plexus palsies, one severe macroglossia, and one accidental extubation. Intravenous access in the small child with achondroplastic dwarfism is made difficult because of the excess, lax skin and subcutaneous tissue. Airway management and laryngoscopy were not difficult and we found that endotracheal tube size was best predicted by the patient's weight and not age. Blood loss was 38 +/- 9 mg X kg-1 in the prone position (n = 8) and 18 +/- 4 mg X kg-1 in the sitting position (n = 16), and was related to the surgical procedure rather than to dwarfism. Our data indicate that complications are more likely to occur in the sitting position, and that these complications are of a serious nature, and every precaution should be taken to avoid their occurrence.

Achondroplasia↗
PubMed1985

Etomidate infusion for neuro-anaesthesia. A case report.

The successful administration of an etomidate infusion as a supplement to droperidol, fentanyl, muscle relaxant, air and oxygen anaesthesia in an 8-hour neurosurgical procedure is described. The merits of this technique are discussed, with particular emphasis on the conduct of anaesthesia in a patient with raised intracranial pressure.

Adolescent↗
PubMed1985

The treatment of resistant hypotension with ornipressin. A case report.

A 50-year-old man underwent emergency aortic valve replacement. He had been treated with five antihypertensive agents before the procedure; this contributed to the development of profound hypotension after induction of anaesthesia. The hypotension did not respond to conventional treatment with an incremental intravenous infusion of phenylephrine HCl, probably due to the direct vasodilator action of the hydralazine group of drugs which renders the peripheral vascular smooth muscle unresponsive to sympathomimetic stimulation. The hypotension did, however, respond rapidly to low-dose infusion of a synthetic vasopressor, ornipressin (POR 8; Sandoz), a drug with a direct action on vascular smooth muscle, especially the capacitance vessels. Ornipressin thus restores vascular smooth-muscle tone even when the integrity of the adrenergic pathways is no longer intact.

Anesthesia, General↗