Incidence and Causes of Failed Spinal Anesthesia

Abstract

Introduction: Spinal anesthesia (SA) is one of the most frequently applied anesthesia procedures today. However, SA failure rate varies between 1 and 17%. The age of the patient, the position at which the procedure is performed, or the characteristics of the technical operation can affect success. In this study, we aimed to compare the most frequent SA failures according to the types of surgery and causes of failure. The results of SA procedures performed in a university hospital were compare to those published in the current literature. Materials and Methods: After obtaining ethics committee ­approval for our study, the hospital archives were examined retrospectively for 1 year with respect to SA procedures. SA application and failure rates were examined. Three or more SA attempts, failed dural puncture, or unsuccessful injection, and anesthesia applications that did not provide sufficient sensory block for surgery despite successful drug treatment were defined as failure. Results: Of all anesthesia procedures, SA was applied at a rate of 23.5%. Our SA failure rate was calculated as 16.6%. Considering a single surgical procedure, obstetric anesthesia was the most common surgery with failed SA (28.7%). The most common cause of failure was insufficient analgesia (32.9%). Discussion: SA failure rates were observed to be in a variable distribution range in the literature, and in some studies, SA failure was defined as a block that did not occur despite a full dose and successful injection, and this rate was found to be 3.9%. The high rate in our study group may be explained by differences in the definition of SA: blocks performed with several trials and any block that could not be applied were also recorded as SA failure. The reasons for failing to apply this procedure is an issue that is worth examining also in terms of patient satisfaction and safety, which is an important issue. Conclusion: Although the definition of unsuccessful SA is confusing, SA failure rates are worth examining and improving for each hospital.