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Biomedical subjects

D F Grum

Publications and source records attributed to D F Grum.

11 recordsLinked to original sources
PubMed1992

Does propranolol alter the vascular response to phenylephrine before or during halothane anaesthesia in patients with coronary artery disease?

Preoperative beta-adrenergic blockade with propranolol, by allowing unopposed alpha-adrenergic stimulation in response to stress, has been suggested as a factor contributing to hypertension following coronary artery bypass surgery (CABG). Thus, one might expect to find an exaggerated haemodynamic response to phenylephrine (PHE), an alpha 1 agonist. To study this, the cardiovascular response to PHE infusion at 30, 40, and 50 microgram.min-1 prior to and during halothane anaesthesia was measured before surgical stimulation during elective CABG in patients taking chronic propranolol therapy and compared with that of patients not taking any cardiovascular medications. Chronic propranolol therapy did not alter the haemodynamic response to PHE, before or during halothane anaesthesia, and the incidence of postoperative hypertension requiring vasodilator therapy was the same for both groups.

Anesthesia, Inhalation↗
PubMed1992

Effect of chronic nifedipine therapy on the haemodynamic response to phenylephrine before and during halothane anaesthesia.

We evaluated the effect of chronic oral nifedipine therapy (30-80 mg day-1) on the haemodynamic response to the alpha 1-agonist phenylephrine (PE) in 10 patients before and during halothane anaesthesia. The response was compared to a control group of eight patients not taking any cardiovascular drugs. No patients had ganglionic, beta-adrenergic, or muscarinic pharmacological blockade as in prior studies in the literature, and thus had intact cardiovascular reflexes. In all patients, PE caused a dose-related increase in arterial pressure and fall in heart rate and cardiac index. The response in patients taking nifedipine was not significantly different from that measured in controls. One-per-cent halothane in oxygen did not alter the overall haemodynamic response to PE in either group.

Adult↗
PubMed1991

Changes in cerebrospinal fluid pressure and spinal cord perfusion pressure prior to cross-clamping of the thoracic aorta in humans.

Little is known about what influences cerebrospinal fluid pressure (CSFP) during anesthesia prior to aortic cross-clamping (AXC). Therefore, this study measured the effect of anesthetic induction, of various drugs administered during the course of surgery prior to AXC, and of hemodynamic changes on CSFP, and calculated spinal cord perfusion pressure (SCPP = mean arterial pressure [MAP] - CSFP) in 11 patients undergoing surgery on the descending thoracic aorta. A lumbar drainage catheter was placed to facilitate drainage of CSF and to measure CSFP. Anesthesia was induced with fentanyl, 50 micrograms/kg, and midazolam, 1 mg, using a pancuronium-metocurine mixture for neuromuscular blockade. Data were collected prior to and after (1) anesthetic induction, (2) mannitol to augment diuresis, (3) sequential use of sodium nitroprusside (SNP) and isoflurane (ISO) to lower MAP by 20%, (4) drainage of spinal fluid, (5) intrathecal injection of papaverine (IP), and (6) AXC. Statistical comparisons of recorded data were made using the least squares mean method and Friedman test. Linear regression was used to test for correlation between CSFP and hemodynamics. Anesthetic induction affected neither hemodynamics nor CSFP. Mannitol significantly increased heart rate, central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and CSFP (P less than 0.05). SNP or ISO altered neither CVP, PCWP, CO, nor CSFP, which remained elevated at the postmannitol infusion level. ISO, unlike SNP, caused a significant decrease in SCPP (P less than 0.005). Subsequent drainage of 20 mL of CSF improved SCPP (P less than 0.05). IP did not have any effect on hemodynamics or CSFP. CSFP showed a strong correlation with CVP (r = 0.86).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Intravenous↗
PubMed1990

Halothane anaesthesia does not modify the cardiovascular response to phenylephrine in man.

Conflicting results exist regarding the ability of halothane to alter the vascular response to alpha 1 adrenergic agonists in animals. Because data from humans are lacking, we studied the haemodynamic response to phenylephrine (PHE) in eight patients about to undergo coronary artery bypass surgery before and during halothane anaesthesia. After obtaining baseline measurements in patients while awake, the responses to PHE infusion at 30, 40, and 50 micrograms.min-1 were determined. New baseline measurements were made following stabilisation during anaesthesia with halothane, one per cent inspired in oxygen, prior to surgical incision. Then the responses to identical PHE doses were measured again. Halothane did not influence the cardiovascular response to PHE: there was no dose-response shift for any cardiovascular variable. No arrhythmias or signs of ischaemia were observed. We conclude that one per cent halothane anaesthesia does not attenuate PHE-induced vasoconstriction in man.

Anesthesia, Inhalation↗
PubMed1990

Appraisal of cerebrospinal fluid alterations during aortic surgery with intrathecal papaverine administration and cerebrospinal fluid drainage.

We have previously described a technique for intrathecal administration of papaverine and cerebrospinal fluid drainage to prevent paraplegia after aortic surgery. Herein we report the cerebrospinal fluid and hemodynamic alterations that occurred in 11 patients who had 30 mg of a specially prepared papaverine hydrochloride 10% dextrose solution injected before aortic cross-clamping and also had cerebrospinal fluid drainage. A mean of 26.6 ml (SD +/- 7.1 ml) was drained before and 34.6 ml (SD +/- 24.1 ml) was drained during aortic cross-clamping. The cerebrospinal fluid pressure increased significantly with anesthetic induction (p less than 0.03), during the period between anesthetic induction and cerebrospinal fluid drainage (p less than 0.005), and with aortic cross-clamping (p less than 0.05). These cerebrospinal fluid pressure alterations were similar to central venous pressure increases with a significant linear correlation between cerebral spinal fluid pressure and central venous pressure before anesthetic induction (r2 = 0.81, p less than 0.005), and both before (r2 = 0.94, p less than 0.005) and after (r2 = 0.74, p less than 0.005) aortic cross-clamping. As expected, cerebrospinal fluid pressure was significantly reduced by cerebrospinal fluid drainage before aortic cross-clamping (p less than 0.001). The administration of intrathecal papaverine had no significant effect on mean arterial pressure, systemic vascular resistance, cerebrospinal fluid pressure, nor the pH of cerebrospinal fluid. Neither were there any complications noted related to the technique. All the patients survived, and no new immediate postoperative paraparesis or paraplegia occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1990

Methemoglobinemia from topical benzocaine.

Acute cyanosis and methemoglobinemia developed following topical application and partial ingestion of benzocaine for esophagogastroduodenoscopy. A diagnosis of acute toxic methemoglobinemia should be considered when cyanosis, with or without neurologic symptoms, occurs following the use of local anesthetics in the absence of cardiopulmonary disease. Laboratory tests should include oxygen saturation and methemoglobin concentration. Management includes supplemental oxygen administration and intravenous methylene blue.

Administration, Topical↗
PubMed1988

Intrathecal papaverine for the prevention of paraplegia after operation on the thoracic or thoracoabdominal aorta.

Eleven patients undergoing operation on the descending or thoracoabdominal aorta were administered papaverine intrathecally in an attempt to protect the spinal cord from ischemic damage. Concurrently, 19 patients, also undergoing operation on the thoracic or thoracoabdominal aorta, were operated on with a variety of conventional techniques, including distal aortic perfusion, but were not given intrathecal papaverine. No signs of early neurologic injury developed in any of the patients in the intrathecal papaverine group, although delayed paraparesis developed in one of the patients (9%; 70% confidence limits = 1% to 28%). On the other hand, eight of 19 patients undergoing operation with conventional techniques had either lower extremity paraparesis or paraplegia postoperatively (42%; 70% confidence limits = 29% to 57%; p = 0.058). Intrathecal papaverine appeared to provide spinal cord protection during thoracic aortic operations, particularly during prolonged periods of aortic cross-clamping. Papaverine was not associated with increased risk and may be superior to other conventionally used modalities. We conclude that continued evaluation of this technique is justified.

Adult↗