Immune response in infants undergoing application of cast: comparison of halothane and balanced anesthesia

Purpose: To study the immunological effects of two types of anesthesia on t he immune response in infants during a minimally stressful surgical procedu re. Methods: The effects of inhalational halothane (halothane + N2O + O-2, spon taneous breathing, n = 12) and conventional balanced anesthesia (thiopental + N2O + O-2 + fentanyl + vecuronium, mechanical ventilation, n = 12) on im mune function were measured in a crossover study in 12 infants undergoing a pplication of casts to the lower extremity or hip joint. Leukocyte and diff erential counts, lymphocyte subpopulations, spontaneous lymphocyte prolifer ative responses as well as responses to phytohemagglutinin (PHA), concavali n A (ConA) and pokeweed mitogen (PWM), and serum cortisol concentration wer e measured before, immediately after and four hours after the end of anesth esia. Results: Halothane anesthesia was associated with a higher percentage of T helper cells than conventional balanced anesthesia [47.1 +/- 1.8 (SEM)%, 48 .1 +/- 2.3% and 50.7 +/- 1.9% before, immediately and four hours-after anes thesia vs 45.7 +/- 1.7%, 44.0 +/- 2.3% and 45.1 +/- 1.9%, respectively, by groups, P < 0.05]. Leukocyte count and the percentages of activated T cells , natural killer cells and B cells showed similar alterations in both group s, and no alterations were observed in the percentages of T lymphocytes or T cytotoxic cells, Lymphocyte transformation response to PWM was decreased four hours after anesthesia in the halothane but not in the balanced anesth esia group. Conclusion: Anesthesia of short duration during minimal surgical stress alt ers lymphocyte subpopulations and lymphoproliferative responses in infants and, furthermore, halothane anesthesia and balanced anesthesia have differe nt effects.