[Effect of intravenous patient-controlled intravenous analgesia with small dose of ketamine during shock stage on cytokine balance in patients with severe burn].

Objective: To investigate the influences of patient-controlled intravenous analgesia (PCIA) with small dose of ketamine solely or combined with fentanyl during shock stage on cytokine balance in patients with severe burn.

Methods: Forty-five patients with severe burn and hospitalized within 24 hours after injury were randomly divided into three groups (n=15 in each group): conventional analgesia therapy group (group CAT), patient controlled intravenous ketamine analgesia group (group PCIKA, intravenous small dose ketamine), and patient controlled intravenous ketamine and fentanyl analgesia group (group PCIKFA, intravenous small dose ketamine combined with fentanyl). In group CAT, patients received intramuscular injection of pethidine 50 mg and phenergan 25 mg when patients complained of pain. In group PCIKA, patients received intravenous infusion with a mixture of ketamine 20 g/L + droperidol 50 mg/L, and in group PCIKFA with a mixture of ketamine 10 g/L + fentanyl 5 mg/L + droperidol 50 mg/L. In two groups of PCIA, patients received loading dose of 1 ml, with background infusion of 1.5 ml/h. Pain scores and side effects of analgesics were determined or observed at the time points of before analgesia and 1, 8, 24, 48 hours after analgesia, and serum cytokines [including interleukin-1 (IL-1), IL-6, tumor necrosis factor-alpha (TNF-alpha)] were measured at the same time points.

Results: Pain scores in PCIFA and PCIKFA groups were significantly lower than that of before analgesia and group CAT (all P<0.01). There were no significant differences in heart rate (HR) and mean artery pressure (MAP) in three groups. No significant difference in side effects was found in three groups. The serum levels of cytokines were significantly lower in two PCIA groups than those of group CAT (all P<0.01).

Conclusion: Patient-controlled intravenous analgesia with small doses of ketamine or combined with fentanyl during shock stage in patients with severe burn give efficient and safe pain relief, and cytokine balance.