Inappropriate mechanical ventilation in patients with acute respiratory distress syndrome can lead to ventilator-induced lung injury (VILI) and increase the morbidity and mortality. Reopening collapsed lung units may significantly reduce VILI, but the mechanisms governing lung recruitment are unclear. We thus investigated the dynamics of lung recruitment at the alveolar level. Rats (n = 6) were anesthetized and mechanically ventilated. The lungs were then lavaged with saline to simulate acute respiratory distress syndrome (ARDS). A left thoracotomy was performed, and an in vivo microscope was placed on the lung surface. The lung was recruited to three recruitment pressures (RP) of 20, 30, or 40 cmH(2)O for 40 s while subpleural alveoli were continuously filmed. Following measurement of microscopic alveolar recruitment, the lungs were excised, and macroscopic gross lung recruitment was digitally filmed. Recruitment was quantified by computer image analysis, and data were interpreted using a mathematical model. The majority of alveolar recruitment (78.3 +/- 7.4 and 84.6 +/- 5.1%) occurred in the first 2 s (T2) following application of RP 30 and 40, respectively. Only 51.9 +/- 5.4% of the microscopic field was recruited by T2 with RP 20. There was limited recruitment from T2 to T40 at all RPs. The majority of gross lung recruitment also occurred by T2 with gradual recruitment to T40. The data were accurately predicted by a mathematical model incorporating the effects of both pressure and time. Alveolar recruitment is determined by the magnitude of recruiting pressure and length of time pressure is applied, a concept supported by our mathematical model. Such a temporal dependence of alveolar recruitment needs to be considered when recruitment maneuvers for clinical application are designed.

Our results show that in patients with synchronous unresected stage IV colorectal adenocarcinoma undergoing single- or multi-agent chemotherapy, after adjusting for confounding variables, definitive resection of the primary site was associated with improved overall survival. Large randomized controlled trials are needed to determine if there is a causal relationship between surgery and increased overall survival in this patient population.

There have been few studies directly comparing the postoperative complications in patients with a diverting ileostomy to patients who were not diverted after low anterior resection (LAR) for rectal carcinoma. This study is a retrospective chart review of all rectal carcinoma patients (99) who underwent a LAR from January 2009 to December 2014 at Loma Linda University Medical Center and Veterans Affairs Loma Linda Healthcare System. A majority of patients were diverted (58% vs 42%). The diverted patients were more likely to have a low tumor location ( P < 0.01), preoperative chemoradiation ( P < 0.01), and more intraoperative blood loss ( P < 0.01). Our study shows a statistically significant higher overall complication rate among patients receiving a diverting ileostomy in the six months after LAR (61% vs 38%, P = 0.02). The difference is due to a higher rate of readmission (27% vs 14%) and acute kidney injury (14% vs 5%) in patients with a diverting ileostomy. It also shows that there is a higher rate of unplanned reoperation (11% vs 6%) due to anastomotic leak (17% vs 5%) in nondiverted patients. Further studies are needed to refine the specific indications to maximize the benefit of diverting ileostomy after LAR for rectal carcinoma.

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