Evaluation and management of patients with pulmonary disease before thoracic and cardiovascular surgery.

The risks of respiratory complications after thoracic and cardiovascular surgeries are particularly high for patients with chronic pulmonary disease and are associated with prolonged hospital stays and increased mortality. The primary goals of preoperative management are to identify risk factors and institute interventions likely to reduce subsequent postoperative pulmonary complications. Smoking, symptomatic obstructive lung disease, respiratory infection, obesity, and malnutrition are all potentially modifiable risk factors. Chest physiotherapy is indicated in all patients regardless of risk factor profile. Providing a thoughtfully designed, multifaceted course of preoperative care can result in a clinically significant reduction in postoperative morbidity and mortality, particularly if instituted well in advance of surgery.

Persistent air leaks in patients receiving mechanical ventilation.

The term bronchopleural fistula (BPF) can be loosely defined as persistent leakage of gas from the airways into the pleural space. A true BPF, however, is located in the central airways, whereas leaks located peripherally are better described by the term parenchymal-pleural fistula (PPF). The presence of a persistent leak in a mechanically ventilated patient is a worrisome prognostic sign independent of the precise origin, yet it is important to distinguish BPF from PPF in this population. Fundamental differences in the pathogenesis and natural history of these two entities dictate divergent approaches to management. This review compares and contrasts the evaluation and management of BPF and PPF in patients receiving mechanical ventilation, and provides an overview of the many nonsurgical interventions used to manage persistent leaks.

Correlation of the physical and genetic maps of the centromeric region of the right arm of linkage group III of Neurospora crassa.

We have cloned three linked genes serine-1 (ser-1), proline-1 (pro-1) and acetate-2 (ace-2) that lie near the centromere on the right arm of linkage group III (LGIIIR) of Neurospora crassa. The ser-1 gene was cloned by sib selection. A chromosomal walk that spans 205 kilobases (kb) was initiated from ser-1. Complementation analysis with clones isolated during the walk allowed identification of the pro-1 and ace-2 genes. Restriction fragment length polymorphism analysis has confirmed the localization of ser-1, pro-1 and ace-2 to the centromeric region of LGIIIR. Genetically, we measured 1% recombination between ser-1 and pro-1 and 2% recombination between pro-1 and ace-2. Physical distances for these intervals were 114 kb from ser-1 to pro-1 and 36 kb from pro-1 to ace-2. Thus, for the pro-1 to ace-2 interval we calculate a physical/genetic correlation of 18 kb/map unit (mu) whereas, in the immediately adjacent, centromere-proximal interval from ser-1 to pro-1, we calculate 114 kb/mu. This provides evidence for a centromere effect, a decrease in recombination frequency as one approaches the centromere.