patient from overdosing. if the patient becomes too sleepy or sedated, he or she makes no more requests. this confers a fail-safe aspect that is lacking in continuous-infusion techniques. if these medications cannot effectively manage the pain, local anesthetic may be directly injected to the nerve in a procedure called a nerve block. in the recovery unit, many vital signs are monitored, including oxygen saturation, heart rhythm and respiration, blood pressure, and core body temperature. postanesthetic shivering is common. apart from causing discomfort and exacerbating pain, shivering has been shown to increase oxygen consumption, catecholamine release, risk for hypothermia, and induce lactic acidosis. a number of techniques are used to reduce shivering, such as warm blankets, or wrapping the patient in a sheet that circulates warmed air, called a bair hugger. if the shivering cannot be managed with external warming devices, drugs such as dexmedetomidine, or other α2-agonists, anticholinergics, central nervous system stimulants, or corticosteroids may be used. in many cases, opioids used in general anaesthesia can cause postoperative ileus, even after non-abdominal surgery. administration of a μ-opioid antagonist such as alvimopan immediately after surgery can help accelerate the timing of hospital discharge, but does not reduce the development of paralytic ileus. enhanced recovery after surgery (eras) is a society that provides up-to-date guidelines and consensus to ensure continuity of care and improve recovery and peri-operative care. adherence to the pathway and guidelines has been shown to associate with improved post-operative outcomes and lower costs to the health care system. perioperative mortality main article: perioperative mortality most perioperative mortality is attributable to complications from the operation, such as haemorrhage, sepsis, and failure of vital organs. over the last several decades, the overall anesthesia related mortality rate improved significantly for anesthetics administered. advancements in monitoring equipment, anesthetic agents, and increased focus on perioperative safety are some reasons for the decrease in perioperative mortality. in the united states, the current estimated anesthesia-related mortality is about 1.1 per million population per year. the highest death rates were found in the geriatric population, especially those 85 and older. a review from 2018 examined perioperative anesthesia interventions and their impact on anesthesia-related mortality. interventions found to reduce mortality include pharmacotherapy, ventilation, transfusion, nutrition, glucose control, dialysis and medical device. interestingly, a randomized controlled trial from 2022 demonstrated that there is no significant difference in mortality between patient receiving handover from one clinician to another compared to the control group. mortality directly related to anaesthetic management is very uncommon but may be caused by pulmonary aspiration of gastric contents, asphyxiation, or anaphylaxis. these in turn may result from malfunction of anaesthesia-related equipment or, more commonly, human error. in 1984, after a television programme highlighting anaesthesia mishaps aired in the united states, american anaesthesiologist ellison c. pierce appointed the anesthesia patient safety and risk management committee within the american society of anesthesiologists. this committee was tasked with determining and reducing the causes of anaesthesia-related morbidity and mortality. an outgrowth of this committee, the anesthesia patient safety foundation, was created in 1985 as an independent, nonprofit corporation with the goal "that no patient shall be harmed by anesthesia". the rare but major complication of general anaesthesia is malignant hyperthermia. all major hospital should have protocol in place with emergence drug cart near the or for this potential complication.