instruction:
Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
question:
Abstract: The ability to breathe spontaneously through an endotracheal tube is a usual prerequisite before an intubated patient can have it removed. Other researchers have measured air flow resistance through endotracheal tubes. In this study, we evaluated work of breathing in joules per min and tension-time index while three normal volunteers breathed through different sized endotracheal tubes. Four 27.5-cm endotracheal tubes were used. Subjects breathed with a constant tidal volume of 500 ml. By increasing respiratory frequency, minute ventilation was increased from 5 to 30 L/min. As tube diameter decreased, work and the tension-time index increased. Changes were magnified at higher minute ventilations through the 6- and 7-mm endotracheal tubes, and the tension-time index critical fatigue level of 0.15 was approached or exceeded.
answer:
Work of breathing through different sized endotracheal tubes.

question:
Abstract: A 15-year-old girl presented with a very large desmoid tumour in her buttock; it extended into the pelvis and thigh and would have required hindquarter amputation for its removal. This was not performed and the tumour underwent spontaneous regression. Fourteen years later the patient is alive and well. The suggestion is made that in some cases a more expectant approach to treatment might be justified for what is essentially a non-malignant condition.
answer:
Spontaneous regression of a desmoid tumour.

question:
Abstract: Seventy two patients (39 women) with colonic adenomas were compared with 72 adenoma free controls (39 women) to investigate the possible association between previous cholecystectomy and the subsequent development of adenomas. Data were gathered retrospectively from medical records. Overall there was no significant association between colonic adenomas and previous cholecystectomy. When women are considered separately, however, eight cases and no controls had undergone cholecystectomy (odds ratio infinity lower 95% confidence limits 1.7, p greater than 0.01). No association between previous cholecystectomy and large bowel adenomas was found in men. Four of nine (44.4%) women with right sided colonic adenomas had undergone previous cholecystectomy compared with only three of 23 (13%) women with left sided adenomas.
answer:
Cholecystectomy and adenomatous polyps of the large bowel.