Prophylactic use of Parenteral Ketamine versus Ondansetron for Prevention of Shivering during Spinal Anesthesia in Hernia Surgeries

Abstract

SUMMARY H ypothermia may cause significant discomfort in the awake patient. Recovery is prolonged not only because a sense of coldness alters mentation and delays awakening, but because drug metabolism is reduced. These considerations are compounded by the negative physiological influences addressed previously. As with most complications in anesthesia, prevention is the best management. Shivering is an involuntary, oscillatory muscular activity that augments metabolic heat production up to 600% above basal level. Shivering is elicited when the preoptic region of the hypothalamus is cooled. Efferent shivering pathway arises and descends from the posterior hypothalamus. Postoperative shivering is a common complication following regional anesthesia in hernia surgeries. Even a small decrease of 0.5°C may induce shivering. Patients often identify feeling cold as one of the most unpleasant aspects of their treatment, sometimes worse than any pain associated with the procedure. Shivering is not only subjectively unpleasant but is physiologically stressful because it elevates blood pressure, heart rate, oxygen consumption, and plasma catecholamine concentrations. Moreover, shivering may aggravate pain and hinder wound closure by simply stretching surgical incisi