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Biomedical subjects

M S Dhamee

Publications and source records attributed to M S Dhamee.

At least 19 recordsLinked to original sources
PubMed2000

The use of esmolol, nicardipine, or their combination to blunt hemodynamic changes after laryngoscopy and tracheal intubation.

UNLABELLED: Laryngoscopy and tracheal intubation (LTI) often provoke an undesirable increase in blood pressure (BP) and/or heart rate (HR). We tested the premise that nicardipine (NIC) and esmolol (ESM) in combination (COMB) would oppose both. Adult surgical patients received pretreatment (randomized) with IV bolus NIC 30 microg/kg (n = 31), ESM 1.0 mg/kg (n = 34), or COMB (one-half dose each, n = 32). Peak BP and HR after LTI were compared with controls (CONT; n = 35) with no pretreatment. Anesthetic induction was standardized: IV thiopental (5-7 mg/kg), fentanyl (1-2 microg/kg), and succinylcholine (1.5 mg/kg). Systolic (S), diastolic (D), and mean (M) BP and HR awake before pretreatment (baseline) were similar in all test groups. No patient was treated for hypotension, bradycardia, or tachycardia after pretreatment or anesthetic induction. Peak HR after LTI was increased versus baseline in CONT and all test groups, but did not differ from CONT among the test groups. Peak SBP and DBP increased versus baseline in CONT, and with ESM and NIC, but not COMB. Peak SBP, DBP, and MBP were increased with ESM versus COMB, and peak DBP with ESM versus NIC. Compared with no pretreatment before the IV induction of general anesthesia, the peak increase in BP after LTI is best blunted by the combination of nicardipine and ESM, compared with either drug alone. No single drug or combination in the doses tested opposed increased HR. IMPLICATIONS: Compared with no pretreatment before the IV induction of general anesthesia, the peak increase in blood pressure after laryngoscopy and tracheal intubation is best blunted by the combination of nicardipine and esmolol, compared with either drug alone. No single drug or combination in the doses tested opposed increased heart rate.

Adrenergic beta-Antagonists↗
PubMed1996

Electrosurgery-induced ventricular fibrillation during pacemaker replacement--a unique mechanism.

Arrhythmias and pacemaker malfunction are known to occur from the use of an electrosurgical device. The present case report describes a patient with sick sinus syndrome who experienced ventricular fibrillation while undergoing surgery. During replacement of his non-functioning cardiac pacemaker under general anesthesia, electrosurgery was used to ensure hemostasis. Electric current may have stimulated myocardial leads present in the surrounding tissue, leading to ventricular fibrillation. The patient was resuscitated from the episode without any residual sequelae. Microshock and possible mechanisms that can lead to ventricular arrhythmias in patients with pacemakers during electrosurgery are discussed.

Adult↗
PubMed1990

Anesthesia machine malfunction simulating spontaneous respiratory effort.

We present a case in which a dip in the capnogram of an anesthetized patient, which may indicate clinical complications such as spontaneous respiratory effort, was caused by a malfunction of the anesthesia delivery system. The rubber diaphragm of the ventilator relief valve was found to be coated with a sticky substance which may have caused adhesion at the valve seat. This adhesion blocked the flow of excess gas to the scavenging system during exhalation. It was demonstrated that a pressure of 5 cm H2O was needed to overcome this adhesion.

Anesthesiology↗
PubMed1990

Cardiovascular effects of pancuronium, vecuronium, and atracurium during induction of anesthesia with sufentanil and lorazepam for myocardial revascularization.

The hemodynamic effects of three commonly used muscle relaxants, pancuronium, vecuronium, and atracurium were investigated during induction of anesthesia with sufentanil and lorazepam in patients undergoing coronary artery bypass surgery. Direct hemodynamic variables were recorded, and indirect parameters were calculated using standard formulae. Changes in heart rate differed with the three muscle relaxants. Pancuronium increased the heart rate whereas vecuronium and atracurium produced a decrease 5 minutes after induction (P less than 0.05). No differences were found in any other parameter during the study. A slow induction with sufentanil, lorazepam, and any of the three muscle relaxants was shown to minimize the hemodynamic changes.

Aged↗
PubMed1990

Pulmonary artery occlusion pressure is not accurate immediately after cardiopulmonary bypass.

Elevated pulmonary vascular resistance (PVR), differential cardiac dynamics, and increased lung water following cardiopulmonary bypass (CPB) have been proposed as limitations to the accuracy of the pulmonary artery occlusion pressure (PAOP) in estimating left ventricular preload. A prospective study of 22 patients undergoing elective myocardial revascularization is described wherein PAOP was compared with directly measured left atrial pressure (LAP). The reliability of PAOP to estimate LAP in the hour immediately following CPB and at 1, 4, 8, and 12 hours post-CPB was examined with repeated measures analysis of variance. Relationships between the PAOP-LAP difference and PVR, core temperature, arterial CO2 tension, and right and left ventricular stroke work indices (RVSWI, LVSWI) were tested by linear regression analysis. There was greater variability in measurements at 15, 30, and 45 minutes immediately after CPB, demonstrated by a pooled correlation coefficient of 0.73 versus 0.90 in the postoperative period. The degree of discrepancy between PAOP and LAP lessened with time. There was no determinable relationship of the PAOP-LAP gradient to PVR, level of PCO2, temperature, RVSWI, or LVSWI. Potential sources of discrepancy include airway pressure effects, position of the measuring catheters, positive end-expiratory pressure, infusion of protamine sulfate, extremes of pulmonary artery pressures, and effects of an open pericardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Mass spectrometer artifact: simultaneous detection of two volatile anesthetics.

In several cases, a mass spectrometer indicated that both enflurane and isoflurane were being detected while only isoflurane was in use. The concentration of expired enflurane reported was always higher than the inspired concentration, but never exceeded 0.66% regardless of the concentration of isoflurane. Such mass spectrometer readings may be evidence of vaporizer contamination or malfunction of the vaporizer; however, in this case, the mass spectrometer was found to be out of calibration. Because mass spectrometers are recent additions to clinical equipment, procedures for routine calibration and maintenance must be carefully scrutinized and evaluated.

Anesthesiology↗
PubMed1986

A re-evaluation of the anxiolytic properties of intramuscular midazolam.

The observed effect of midazolam on anxiety is equivocal in part because previous studies have not ruled out pre-treatment differences in anxiety scores between patients who received midazolam and those who did not (controls). This study re-examines the anxiolytic effect of premedication with intramuscular midazolam using a sample size calculated to be of sufficient size to rule out population differences as a variable affecting treatment results. In the midazolam group (n = 49) anxiety scores were determined prior to administration of midazolam 0.07 mg/kg intramuscularly, and again 60 minutes later. In the control group (n = 47) anxiety scores were determined prior to intramuscular injection of a similar volume of matching placebo (midazolam vehicle), and again 60 minutes later. No differences in anxiety scores between groups either before treatments or 60 minutes after treatments were observed. Within both groups, anxiety scores at 60 minutes were no different from pre-treatment scores. In this study midazolam did not produce a statistically significant decrease in pre-operative anxiety scores at 60 minutes following intramuscular administration.

Adolescent↗
PubMed1984

Postoperative unilateral facial oedema: a complication of acute flexion of the neck.

A case report describing a complication following the use of the sitting position and an extreme flexed position of the neck is presented. The patient developed unilateral oedema of the face, tongue and soft tissues of the mouth. The trachea was reintubated and the oedema subsided without treatment. The cause of the oedema is believed to be obstruction of the venous drainage of the head and neck.

Airway Obstruction↗
PubMed1984

Premedication with intramuscular midazolam: effect on induction time with intravenous midazolam compared to intravenous thiopentone or ketamine.

Our study sought to determine whether premedication with intramuscular midazolam would decrease the time to induction of anaesthesia with intravenous midazolam, and if so whether induction of anaesthesia would be as rapid as with thiopentone or ketamine, intravenously. Eight-nine patients, ASA physical status I or II, received midazolam 0.2 mg X kg-1, thiopentone 3.0 mg X kg-1, or ketamine 2.0 mg X kg-1 intravenously 60-90 min after intramuscular injection of either midazolam 0.07 mg X kg-1 or matching placebo. Time to induction of anaesthesia or the dose required to induce anaesthesia with intravenous midazolam was not decreased by midazolam premedication. Both with or without premedication, midazolam induction time was longer than with thiopentone or ketamine. Midazolam induction was associated with a lower incidence of blood pressure increase than with ketamine induction, and a lower incidence of apnea than that with either thiopentone or ketamine.

Adolescent↗