Spinal anaesthesia produces few adverse effects on the respiratory system as long as unduly high blocks are avoided. As control of the airway is not compromised, there is a reduced risk of airway obstruction or the aspiration of gastric contents. This advantage may be lost with too much sedation. There is little risk of unrecognised hypoglycaemia in an awake patient. Diabetic patients can usually return to their normal food and insulin regime soon after surgery as there is less sedation, nausea and vomiting.
Spinal anaesthesia provides excellent muscle relaxation for lower abdominal and lower limb surgery.
Blood loss during operation is less than when the same operation is done under general anaesthesia. This is as a result of a decreased blood pressure and heart rate, and improved venous drainage which results in less oozing. Splanchnic blood flow. Because of its effect on increasing blood flow to the gut, spinal anaesthesia reduces the incidence of anastomotic dehiscence. The bowel is contracted by spinal anaesthesia and sphincters relaxed although peristalsis continues.