Eighty patients(American Society of AnesthesiologistsⅠ-Ⅱ)scheduled for elective unilateral inguinal hernia surgery with spinal anesthesia between January and June 2016 were randomized into two groups with 40 in each group. Patients were intravenously injected with normal saline (5 ml) in control group or hydromorphone 5 μg/kg (diluted to 5 ml) in intervention group after spinal anesthesia. Tympanic temperature and the incidence of shrivering were measured before and after spinal anesthesia at predetermined intervals. Side effects during surgery and the first 48 h after surgery were recorded. Rescue drug tramadol 0.5 mg/kg was given intravenously to patients with grade ≥2 shivering for more than 5 min duration. Tympanic temperature decreased significantly compared to the baseline from 20 min in control group and from 10 min in intervention group after spinal blocking(P<0.05), while there were no significant differences in tympanic temperature at the same time points between two groups(P>0.05). The incidence of shivering was significantly lower in intervention group [17.5%(7/40) ] than that in control group [47.5%(19/40), χ²=8.205, P=0.004]. The incidence of nausea and vomiting was 5.0%(2/40)in intervention group and 0.0% (0/40) in control group (χ²=2.051, P=0.494). The incidence of sedation was not significantly different between control group [0.0%(0/40)] and intervention group[10.0%(4/10) , χ²=4.211, P=0.116]. The use of rescue tramadol was more frequently in control group [32.5%(13/40)] than that in intervention group [7.5%(3/40), χ²=7.812, P=0.01]. The results indicate that intravenous hydromorphone can significantly attenuate the incidence of shivering after spinal anesthesia for inguinal herniorrhaphy repair surgery with minimum side effects.

Hydromorphone; Shivering; Anesthesia, spinal; Hernia, inguinal