Incidência e causas de falhas em anestesia subracnóidea em hospital particular: estudo prospectivo / Incidence and causes of failures in spinal anesthesia in a private hospital: a prospective study

RESUMO

Background and objectives - Recent studies in the USA and Finland in three large university affiliated hospitals and in a small community hospital showed the incidence of failures in spinal anesthesia to vary between 3 an 17 per cent. Considering the lack of similar studies in the Brazilian literature, we decided to study the incidence of and the factors associated with failures in spinal anesthesia in a private hospital. Methods - This prospective stdy involved 778 consecutive spinal anesthetics performed along 18 months by experienced anesthesiologists. The anesthetics were performed with 25G, 27G or 29G needles, with plain or glucose containing anesthetic solutions. The following local anesthetics, from different laboratories, were used 5 per cent hyperbaric lidocaine (laboratories A and B), 2 per cent lidocaine (laboratory A), 0.5 per cent hyperbaric bupivacaine (laboratories A and B) and 0.5 per cent isobaric bupivacaine (laboratory A). Anesthetic failures were classified as follows 1) no analgesia; 2) insufficient level of analgesia; 3) pain during peritoneum traction; 4) insufficient duration of analgesia. Anesthetic failures were also related to the puncture site and to the patient's position during injection. Results - The overall failure rate was 8.3 per cent. The failure rate was higher with 29G needles and lower with 25G needles and higher when the puncture was performed in the sitting position. No significant differences were observed regarding different laboratories, plain or glucose containing solutions and puncture site (L2-L3,L3-L4). A significant lower incidence of failure was observed with isobaric colutions. Conclusions - Various causes may have contributed to the failures of spinal anesthesia observed in this study. Most of them, however, were associated with technical factors