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Biomedical subjects

C Verghese

Publications and source records attributed to C Verghese.

At least 19 recordsLinked to original sources
PubMed1996

Clozapine withdrawal effects and receptor profiles of typical and atypical neuroleptics.

Withdrawal effects of neuroleptics have not received much attention. Clozapine withdrawal phenomena have been attributed to psychosis arising from D2 supersensitivity, which is unlikely since it has minimal action on D2 receptors. The time course and clinical features of this phenomenon suggest that cholinergic overdrive and gamma-aminobutyric acid (GABA) supersensitivity occurs after withdrawal, since it is strongly anticholinergic and has a GABAergic action. Recently, a number of patients showed marked decompensation when they were switched from clozapine to risperidone, especially when they were rapidly tapered off clozapine. This was probably more due to withdrawal effects than the primary psychosis or a lack of efficacy of risperidone. A slow withdrawal schedule would facilitate homeostatic mechanisms; anticholinergics would be useful in clozapine withdrawal. This area has not received any attention from researchers, nor are there any guidelines for clinicians. This will be particularly important with the widespread use of atypical agents in the future.

Antipsychotic Agents↗
PubMed1996

Problems and progress in the diagnosis and treatment of polydipsia and hyponatremia.

Fluid-electrolyte balance is regulated within a narrow range and disturbances in this system are unusual in animals and humans. Studies from the preneuroleptic era to date suggest that up to 25 percent of patients with schizophrenia have polydipsia, suggesting that it is related to the pathophysiology of the psychoses. Polydipsia and the related phenomenon of hyponatremia cause considerable mortality and morbidity. Prevalence studies are limited by imprecise measures available at present. The treatment was limiting water intake when patients reached critical levels of water retention, which however did not improve polydipsia. Recent case reports and open studies have shown that clozapine improves both polydipsia and water retention. The response occurs at low doses and is not related to improvement in psychosis. This may not be applicable to all patients and better understanding of the pathophysiology of polydipsia-hyponatremia would lead to more empirically derived treatments.

Behavior Therapy↗
PubMed1996

Survey of laryngeal mask airway usage in 11,910 patients: safety and efficacy for conventional and nonconventional usage.

A survey of laryngeal mask airway (LMA) usage was conducted to provide general information about safety and efficacy with special emphasis on controversial issues such as positive pressure ventilation (PPV), prolonged anesthesia, and laparoscopic and nonlaparoscopic intraabdominal surgery. During the 2-yr study period, of the 39,824 patients who underwent general anesthesia, 11,910 (29.9%) patient airways were managed with the LMA. Forty-four percent underwent PPV. Placement was successful in 99.81%, and in 23 patients the LMA was abandoned in favor of the tracheal tube (TT). Use of the LMA for any intraabdominal procedure was considered nonconventional and occurred in 2222 (18.7%) patients. On 579 occasions procedures lasted > 2 h. A total of 44 critical incidents were documented. Eighteen (0.15%) were related to the airway and none required intensive care management. There were 26 critical incidents not related to the airway which resulted in two admissions to the intensive care unit and one death. There were three cases of failed tracheal intubation managed with the LMA. This survey demonstrates that the LMA technique is safe and effective for both spontaneous and controlled ventilation. Use of the LMA for gynecologic laparoscopy, gynecologic laparotomy, and procedures > 2 h also appears safe.

Adolescent↗
PubMed1995

Treatment of polydipsia and hyponatremia in psychiatric patients. Can clozapine be a new option?

Polydipsia occurs frequently in chronic schizophrenic patients, some of whom develop intermittent hyponatremia. Most therapeutic efforts have tried to control the hyponatremia. Four schizophrenic patients, followed for more than one year, showed improvement on clozapine. Case 1 was an outpatient without history of hyponatremia who improved from polydipsia and psychosis. The last three were inpatients with polydipsia, intermittent hyponatremia, and psychosis who showed minimal improvement of psychosis but significant decrease in polydipsia and water intoxication. Case 2 relapsed to polydipsia when clozapine was discontinued on two occasions. Case 3 demonstrated polyuria during 39% of days before clozapine and in 0% of days after two weeks of clozapine. In case 4, most baseline sodium levels were abnormal, but all became normal after clozapine. A time-series analysis for intervention effects showed a significant effect of clozapine (p = .017). The limited information provided by these case reports suggest the need for controlled studies of the clozapine effect on polydipsic patients.

Adult↗
PubMed1995

A comparison of clinical index and ejection fractions in predicting cardiac complications following infrarenal aortic reconstruction.

OBJECTIVE: To compare the Detsky clinical cardiac risk index with ejection fraction measurements in predicting postoperative cardiac events. DESIGN: Prospective study. SETTING: District General Hospital. MATERIALS: 48 patients undergoing infrarenal aortic reconstruction. CHIEF OUTCOME MEASURES: Ejection fractions were measured both by echocardiography and a technetium 99 MUGA scan. MAIN RESULTS: Three patients developed four major cardiac events (LVF three, fatal myocardial infarction one). Fourteen patients experienced 15 minor cardiac events (arrhythmia 11, ST segment depression four). The clinical index predicted postoperative cardiac problems (p = 0.0001). There was no correlation between ejection fraction measurement and postoperative cardiac events nor between ejection fraction measurements and the clinical index. Combining the index with ejection fraction measurement provided no additional information over the index alone. CONCLUSIONS: Calculation of a clinical index before aortic reconstruction is a simple and reliable way of selecting patients who are at risk of developing postoperative cardiac events.

Adult↗
PubMed1995

A new laryngeal mask prototype. Preliminary evaluation of seal pressures and glottic isolation.

A new prototype laryngeal mask airway is described which incorporates a second mask to isolate the upper oesophagus and a second dorsal cuff to increase the seal against the glottis. We have made a within-patient comparison of seal pressures between the prototype and standard laryngeal mask airway in 20 patients, and determined if the prototype facilitates functional isolation of the glottis and upper oesophagus. Leak pressure was found to be significantly higher for the prototype and equalled or exceeded 5.0 kPa in all patients (p < 0.001). The prototype laryngeal mask airway provided functional isolation in all patients as judged by leak and placement of a gastric tube via the oesophageal mask. Ease of insertion and incidence of pharyngeal morbidity appeared similar to the standard laryngeal mask, but were not formally tested. The prototype laryngeal mask airway exhibits potentially useful new features which justify further evaluation and development.

Adult↗
PubMed1994

Polydipsia and water intoxication in psychiatric patients: a review of the epidemiological literature.

Polydipsia among chronic psychiatric patients is poorly understood and underdiagnosed. It may have three stages: simple polydipsia, polydipsia with water intoxication, and physical complications. Epidemiological surveys have used staff reports and polyuria measures to identify polydipsic patients. Water intoxication has been screened by chart review, weight, or serum sodium data. According to these surveys, polydipsia, not explained by medically induced polyuria, may be present in more than 20% of chronic inpatients. Up to 5% of chronic inpatients had episodes of water intoxication although mild cases may have been missed. Single time point surveys show that 29% of polydipsic patients had presented water intoxication. Methodologically limited clinical studies suggest that polydipsia with water intoxication rather than simple polydipsia may be associated with poor prognosis in schizophrenia. Epidemiological surveys found polydipsia with water intoxication to be associated with chronicity, schizophrenia, smoking, some medications, male gender, and white race. New pathophysiological models need to elucidate these findings.

Chronic Disease↗
PubMed1993

Neuroendocrine factors influencing polydipsia in psychiatric patients: an hypothesis.

Polydipsia and water intoxication cause considerable morbidity and mortality in chronic psychiatric patients. The pathophysiology of the disorder is unknown, and there is no effective treatment. Angiotensin II is an important dipsogen in animals; in humans, some conditions with abnormal thirst are associated with increased angiotensin function. Chronic D2 dopamine receptor blockade increases angiotensin II-induced thirst in animals; in humans, increased peripheral response to angiotensin II is documented. Chronic D2 blockade with typical neuroleptics may increase sensitivity to angiotensin II and induce thirst. Clozapine, which has negligible D2 blocking action may improve polydipsia. Recent case reports demonstrate improvement of polydipsia during clozapine therapy. Angiotensin II releases vasopressin; this could explain water intoxication, which occurs later in the syndrome. This paper suggests an etiological model and a treatment modality for this disorder.

Antipsychotic Agents↗
PubMed1993

Prospective survey of the use of the laryngeal mask airway in 2359 patients.

Patients undergoing anaesthesia in which the laryngeal mask airway was used were prospectively audited over a 6-month period. A simple record sheet was completed at the time of anaesthetic administration and 2359 completed forms were analysed to assess problems encountered with its use. It was used successfully in 2350 patients (99.61%); of these, 1399 patients (59%) breathed spontaneously through the airway and 960 patients (41%) underwent intermittent positive pressure ventilation of the lungs. Two patients (0.08%) were reported to have regurgitated during the use of the laryngeal mask airway, but no serious sequelae associated with its use were encountered.

Adolescent↗