Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.

Ex Input:
Abstract: Prolonged exposure to nitrous oxide produces a recognized neurologic syndrome. We report clinical and electrophysiologic studies of nervous system involvement in a 25-year-old student who abused nitrous oxide. He developed signs of a sensorimotor polyneuropathy and of myelopathy. Routine blood studies, CSF examination, and myelogram were normal. Clinical electrophysiologic studies were performed serially. Nerve conduction studies demonstrated reduced amplitude and slowed sensory potentials, and mildly prolonged late responses. Sensory evoked potentials revealed prolonged latency of scalp-evoked potentials from tibial nerve stimulation with normal median nerve values. The foveal visual evoked potential was delayed in the right eye, with normal visual acuity, funduscopic examination, and spatial contrast sensitivity. Repeat electrophysiologic studies demonstrated improvement. Nitrous oxide produces multifocal reversible dysfunction within the nervous system similar to that described in patients with vitamin B12 deficiency.

Ex Output:
Nitrous oxide: clinical and electrophysiologic investigation of neurologic complications.

Ex Input:
Abstract: Pulmonary edema due to upper airway obstruction can be observed in a variety of clinical situations. The predominant mechanism is increased negative intrathoracic pressure, although hypoxia and cardiac and neurologic factors may contribute. Laryngospasm associated with intubation and general anesthesia is a common cause of pulmonary edema in children. However, only seven cases of pulmonary edema presumably due to laryngospasm have been reported in adolescents and adults. Five of the seven had other risk factors for upper airway obstruction, and in four, the diagnosis of "laryngospasm" could be explained by other factors. Patients with underlying risk factors for upper airway obstruction, such as a forme fruste of sleep apnea or nasopharyngeal abnormalities, appear to be at increased risk for the development of pulmonary edema in the setting of intubation and anesthesia. This form of pulmonary edema usually resolves rapidly without the need for aggressive therapy or invasive monitoring.

Ex Output:
Post-extubation pulmonary edema following anesthesia induced by upper airway obstruction. Are certain patients at increased risk?

Ex Input:
Abstract: It has been postulated that increased energy expenditure results in shortened survival. To test this "rate-of-living theory" we examined the effect of raising energy expenditure by means of cold exposure on the longevity of rats. Male 6-mo-old SPF Long-Evans rats were gradually accustomed to immersion in cool water (23 degrees C). After 3 mo they were standing in the cool water for 4 h/day, 5 days/wk. They were maintained on this program until age 32 mo. The cold exposure resulted in a 44% increase in food intake (P less than 0.001). Despite their greater food intake, the cold-exposed rats' body weights were significantly lower than those of control animals from age 11 to 32 mo. The average age at death of the cold-exposed rats was 968 +/- 141 days compared with 923 +/- 159 days for the controls. The cold exposure appeared to protect against neoplasia, particularly sarcomas; only 24% of the necropsied cold-exposed rats had malignancies compared with 57% for the controls. The results of this study provide no support for the concept that increased energy expenditure decreases longevity.

Ex Output:
Longevity of cold-exposed rats: a reevaluation of the "rate-of-living theory".