Nutrition for the respiratory insufficient patient.

Malnutrition is fairly common in patients with chronic obstructive pulmonary disease, the more severe the airway obstruction the more severe the nutritional status. The consequences of nutritional depletion on respiratory and immune systems are ventilatory compromise and susceptibility to infection. Diaphragm muscle mass and thickness is decreased in patients with COPD. This results in decreased maximum voluntary ventilation and diminished inspiratory pressure. Malnutrition is one of the causes of failure to wean in patients with respiratory failure. Malnutrition also has profound effects on cell-mediated immune response and humoral immunity with reduced levels of secretory IgA. In patients with COPD, colonization of respiratory tract bears a direct relationship with parameters of nutritional status. Patients with significant nutritional impairment have more tracheal cell bacteria adhered to and the tracheas were more frequently colonized by Pseudomonas species. The improvement of nutrition in these patients resulted in less bacterial cell binding to tracheal epithelial cells.

Ventilatory support by pacing of the conditioned diaphragm in quadriplegia.

We provided full-time ventilatory support in five patients with respiratory paralysis accompanying quadriplegia by continuous electrical pacing of both hemidiaphragms simultaneously for 11 to 33 months through the application to the phrenic nerves of a low-frequency stimulus. The strength and endurance of the diaphragm muscle increased with pacing. Biopsy specimens taken from two patients who had uninterrupted stimulation for 6 and 16 weeks showed changes suggestive of the development of fatigue-resistant muscle fibers. When we compared these results with those of our earlier experience with intermittent unilateral stimulation of the diaphragm in 17 patients with respiratory paralysis, we found that continuous bilateral pacing using low-frequency stimulation appeared to be superior because of more efficient ventilation of both lungs, fewer total coulombs required to effect the same ventilation, and absence of myopathic changes in the diaphragm muscle. For patients with respiratory paralysis and intact phrenic nerves, continuous simultaneous pacing of both hemidiaphragms with low-frequency stimulation and a slow respiratory rate is a satisfactory method of providing full-time ventilatory support.

Alterations in the antibacterial properties of rabbit pulmonary macrophages exposed to wood smoke.

We studied the local response of the bronchoalveolar cell population after acute exposure to smoke from pyrolysis of Douglas fir wood. Cell viability experiments and function of the pulmonary macrophages were assessed, including adherence to surfaces, bacterial phagocytosis, and the intracellular bactericidal process. The smoke-exposed group (n=23) when compared with control animals (n=15) produced a significantly greater total cell yield (p less than 0.01) on bronchoalveolar lavage. There was no increase in the percentage of polymorphonuclear leukocytes. As carboxyhemoglobin levels increased, macrophage adherence to glass decreased (r = -0.79, p = 0.0001). Pulmonary macrophages from exposed animals were 33% less adherent at 120 min in vitro; however, these nonadherent smoke-exposed macrophages remained viable (55 to 78% viable by trypan blue dye exclusion). Both the phagocytic rate (361 14C cpm/unit time) and the maximal number of bacteria associated (at 60 min) with the exposed macrophages were significantly less than in the sham-exposed animals (uptake = 672 14C cpm/time, p less than 0.002 for each). The antibacterial properties of pulmonary macrophages are adversely affected by exposure to wood pyrolysis.