The influence of calcium alginate haemostatic swabs upon operative blood loss in adenotonsillectomy. Although adenotonsillectomy is regarded as a minor procedure, it has been shown that 18% of patients may experience an operative blood loss of 10-20% of the total blood volume. The aim of this study was to determine whether calcium alginate haemostatic swabs reduce operative blood loss in adenotonsillectomy. Seventy-two patients (ages 2-12 years) entered a prospective trial in which the operation was performed either with normal gauze swabs or calcium alginate swabs. Thirty-six children were randomized to each group. The mean blood loss was found to be 34.9 ml (2.07% of total blood volume) and 47.8 ml (2.97% of total blood volume) respectively. Although there was no significant reduction in operative blood loss using calcium alginate, in both groups the blood loss was much smaller than that stated by the majority of previous workers. 