Stress reduction and HIV disease: a review of intervention studies using a psychoneuroimmunology framework.

The field of psychoneuroimmunology (PNI) posits that relationships exist between stress, immunological impairment, and health outcomes. Accumulating evidence suggests that stress may hasten HIV disease progression by increasing viral replication, suppressing immune response, and inducing deleterious health-related behaviors. Interventions that attenuate the effects of stress are postulated to operate by altering cognitive perception and/or modulating neuroendocrine and sympathetic reactivity. A review of HIV/PNI intervention studies is presented as a guide for the inclusion of stress reduction interventions in comprehensive plans of care for HIV-infected individuals. Although effect and sample sizes are small, the results of these studies provide support for a positive effect of various interventions on immunological and health-related indices in HIV-infected individuals.

Stress and HIV disease progression: psychoneuroimmunological framework.

Psychoneuroimmunology (PNI) is the study of the interrelationships among behavior, neural and endocrine function, and the immune system. PNI investigates the relationships among stress, physiological dysregulation, and health outcomes. Research has supported the theory that emotional distress and the resultant neuroendocrine activation can induce immune system suppression. This suppression has significant implications for disease susceptibility and progression. HIV disease and its extensive immunological consequences are explored within this framework. Potential physiological pathways that may mediate stress-induced dysregulation within the context of HIV disease are identified. Key HIV-related PNI research studies are reviewed and critically analyzed. Implications for nursing practice and research are discussed.

A method for producing constant plasma concentrations of drugs. Application to methohexitone.

A delivery system in which a dilute infusion of methohexitone is continuously added to a smaller volume of more concentrated solution has been used to infuse exponentially decreasing drug concentrations at a constant rate of infusion. The constants for calculation of concentrations and infusion rate are described. It was possible to achieve and maintain the target plasma concentration required to produce anaesthesia in conjunction with nitrous oxide in oxygen. Methohexitone is the only available drug suitable for this technique, but it requires frequent opioid supplementation and is not the ideal drug for such a technique.

Sensitivity to propofol in the elderly.

Two studies were carried out on 609 fit, unpremedicated patients to assess the influence of patient age on the response to the rapidly-acting hindered phenol, propofol, which is being evaluated for induction of anaesthesia. In the first study, 1.25 mg/kg was injected over 20 seconds followed by 10-mg increments every 15 seconds until loss of verbal contact. This showed a great individual variation in response to the drug. A reduction in the 'induction' dose was found in elderly patients, which became marked around 60 years. In the second (340), doses ranging from 1.5-3.0 mg/kg in patients under 60 years and 1.25-2.25 mg/kg in those over 60 years were injected as a bolus over 20 seconds. Doses of 2.25-2.5 mg/kg were required to induce anaesthesia in patients under 60 years, whilst 1.5-1.75 mg/kg was adequate in those over 60 years. Side effects were more marked with the rapid injection and doses in excess of 1.75 mg/kg caused significant hypotension and apnoea in the elderly. These studies reveal marked sensitivity to propofol in the elderly with respect to both induction dose and acute toxicity.

Effect of pretreatment with ranitidine on the hypnotic action of single doses of midazolam, temazepam and zopiclone. A clinical study.

Patients receiving midazolam, temazepam or zopiclone by mouth as premedication for minor gynaecological surgery were pretreated with either ranitidine or an inert tablet. Pretreatment with ranitidine was associated with a greater degree of drowsiness at 20 and 40 min after midazolam, and a shorter mean time to peak hypnotic effect than in the non-pretreated group. Ranitidine did not affect the degree of drowsiness in the patients receiving temazepam or zopiclone.

Propofol ('Diprivan') by intermittent bolus with nitrous oxide in oxygen for body surface operations.

The use of propofol for induction and maintenance of anaesthesia by intermittent bolus injection in 37 patients undergoing body surface operations is described. This technique gave good operating conditions in most of the patients in the series. With an induction dose of 2.5 mg/kg propofol, a dose of 11.25 mg/kg/h was found to be the median dose requirement for maintenance of anaesthesia in this study. This dose will be used to calculate infusion rates for future studies with the drug.

Age affects the induction dose of propofol ('Diprivan').

A standard method (fixed initial dose of 1.25 mg/kg followed by 10 mg every 15 s) for studying the induction dose of propofol showed a marked falling off in requirements in fit unpremedicated patients aged 60 y and over. With this slow technique of administration, side effects were rare, even in the elderly.

Changes in liver function tests after propofol ('Diprivan').

Changes in three recognized liver function tests are reported following the use of propofol in 30 fit, unpremedicated women in whom propofol was used as the main anaesthetic agent. Doses of 140 to 330 mg were given, together with nitrous oxide and oxygen. All patients were undergoing minor gynaecological operations and all conformed to Grade 1 physical status of American Society of Anesthesiologists Classification. In none of these patients was there hypoxia or hypercarbia at any time during or following anaesthesia and none of the patients received any other drugs until completion of the study. No significant changes in liver enzymes (aspartate transaminase and alanine transaminase) or in serum alkaline phosphatase were detected.