Biomedical subjects
Publications and source records attributed to D Michaloudis.
This case report describes the anaesthetic management of a patient with sporadic-type long QT interval syndrome (LQTS), and increased QT dispersion, who presented for removal of an ovarian cyst. Beta adrenergic blockade and adequate depth of anaesthesia for successful management is emphasized. The successful use of epidural administration of lignocaine and opioids in addition to general anaesthesia is described.
Prolongation of the QT interval may cause potentially hazardous arrhythmias. The effects on the QT interval (QTc, corrected for heart rate) of isoflurane and halothane followed by vecuronium have been investigated during induction of anaesthesia in 51 patients. All patients were ASA 1 or 2, without cardiovascular problems or electrolyte abnormalities and were not receiving medication. Midazolam 0.08 mg.kg-1 was administered intramuscularly for premedication. Anaesthesia was induced with either isoflurane (n = 26) or halothane (n = 25), and the inspired concentration increased to reach an end-tidal concentration of 2.5% to 3%. Recordings of ECG, heart rate, systolic and diastolic arterial pressure were obtained at the following times: prior to induction of anaesthesia; 1 min and 3 min after a stable end-tidal concentration had been reached; 1 min and 3 min following vecuronium administration, at the time of tracheal intubation and 1 min and 3 min later. Halothane significantly shortened QTc (p < 0.05 to p < 0.001), in contrast to isoflurane which prolonged it (p < 0.01). The heart rate decreased (p < 0.01 to p < 0.001) after induction of anaesthesia with halothane and returned to pre-induction values after tracheal intubation. In contrast, heart rate increased after induction with isoflurane and increased further after laryngoscopy and tracheal intubation (p < 0.001). In the isoflurane group, ST depression was noticed in seven patients and nodal rhythm in two, while in the halothane group seven patients developed nodal rhythm and, in two patients, ventricular ectopics were recorded. There were no sequelae. In both groups, systolic and diastolic arterial pressure decreased after induction of anaesthesia (p < 0.01 to p < 0.001), increasing again after intubation.
We investigated the intra-operative application of intraperitoneal perfusion of hyperthermic chemotherapy and its effects on cardiovascular status and oxygen consumption and delivery in 11 patients following laparotomy for surgical resection of recurrent tumours or peritoneal metastases. Closed peritoneal irrigation was carried out with perfusate at a temperature of 45-47 degrees C. External cooling was applied during the procedure to prevent systemic hyperthermia. Data were collected 5 min before the commencement of the hyperthermic peritoneal perfusion, at 5, 30, 60 and 90 min during perfusion and 5 min after perfusion was discontinued. During the hyperthermic perfusion period, the core body temperature increased significantly but remained within clinically acceptable values. Heart rate, central venous pressure and pulmonary artery pressure increased significantly during perfusion; these returned to control values immediately after discontinuation of perfusion, except for the heart rate, which remained high. Mean arterial pressure, cardiac output, oxygen delivery and oxygen consumption did not change significantly although a metabolic acidosis developed during the study period. These findings suggest that the intraperitoneal perfusion of hyperthermic chemotherapy may be safe in humans, provided that appropriate monitoring, cooling and technical support are applied.
Ninety patients were allocated randomly to three groups for airway maintenance during paediatric outpatient dental extraction: laryngeal mask airway, nasal mask with nasopharyngeal airway, or nasal mask alone. Surgical access was better with the laryngeal mask. Airway maintenance was easier with the laryngeal mask than the nasopharyngeal airway, and both were better than nasal mask alone. No patient became hypoxic with the laryngeal mask, five patients became hypoxic with the nasal mask and two with the nasopharyngeal airway at corresponding periods, although the differences were not statistically significant. The laryngeal mask airway is recommended for paediatric outpatient dental anaesthesia.
Drugs with anti-emetic properties can exert their actions at more than one receptor site, histamine H1, muscarinic cholinergic or dopaminergic D2 receptors. This study was designed to test the hypothesis that a combination of drugs acting at different receptor sites in lower than standard doses would be at least as effective as a standard therapeutic dose of a single anti-emetic agent. A combination of droperidol, hyoscine and metoclopramide in subtherapeutic doses has been shown to be at least as effective as droperidol (1.25 mg) alone. In both groups there was a low incidence of emetic sequelae in the first 3 hours postoperatively.