Spinal anesthesia involves the direct application of local anesthetic drugs to nerve roots that enter and exit the spinal cord. According to the American Society of Regional Anesthesia and Pain Medicine, spinal anesthesia is preferred over general anesthesia for many orthopedic, urologic, gynecologic, obstetric and vascular surgical procedures. As with any medical treatment, spinal anesthesia sometimes causes complications.
Cardiac Arrest
Survey data from the American Society of Anesthesiologists' "Closed Claim Project," which retrospectively evaluated malpractice cases in the 1990s and 2000s, indicate that the rate of cardiac arrest due to spinal anesthesia may be as high as one per 1,500 cases. Unexpectedly, most cases appeared in younger, healthier patients who were otherwise classified as low risk for cardiac complications of anesthesia. As a result, the ASA now recommends treating all spinal anesthesia patients with intravenous fluids before the start of surgery. In addition, for patients who show even modest decreases in heart rate or blood pressure under spinal anesthesia, the ASA recommends immediate correction with drugs such as atropine, ephedrine and epinephrine.
Respiratory Failure
According to anesthesiologist Wayne Kleinman in the 2006 edition of "Clinical Anesthesiology," respiratory failure in patients under spinal anesthesia usually begins one of two ways. First, in nearly all patients, spinal anesthesia produces a decrease in blood pressure. For some, this means that not enough blood reaches the brain centers that control respiration, resulting in missed breaths and, ultimately, insufficient oxygen. Second, narcotic drugs increasingly used along with local anesthetics in spinal anesthesia directly suppress the brain's respiratory centers. While respiratory failure can be treated with mechanical ventilation, Kleinman recommends preventing the problem in the first place by aggressively monitoring oxygenation using a pulse oximeter, followed by an oxygen mask or nasal cannula oxygen for those who need it.
Neurological Injuries
Approximately one in 220,000 patients, says Kleinman, develops a serious neurological injury after spinal anesthesia. Common examples include paraplegia, which is the loss of ability to move; paresthesia, the loss of ability to feel; and the loss of control over bowel or bladder functions. Since spinal anesthesia is performed at the L1 level of the spinal cord---L3 in children---most injuries affect the legs, buttocks, genitals or lower back. Almost all injuries resolve spontaneously over the course of a few days or weeks, says Kleinman. Some, unfortunately, are permanent.
References
- "Clinical Anesthesiology, 4th Edition;" G.E. Morgan et al.; 2006
- "Anesthesiology;" Injuries Associated With Regional Anesthesia; L.A. Lee et al.; 2004
- American Society of Regional Anesthesia and Pain Medicine: Patient Information
