Respiratory neuromuscular response to CO2 rebreathing with inspiratory flow resistance in humans

The effects of inspiratory flow resistance on mouth occlusion pressure (P0.15) and diaphragmatic EMG (EMGdi) responses to CO2 rebreathing were studied in normal subjects. Occlusion pressures were measured 150 msec after onset of an inspiratory effect; EMGdi was analyzed as a moving time average and quantified in terms of peak activity and rate of rise of activity. After a control CO2 response was obtained in each subject, rebreathing was repeated 30 min later with either of two inspiratory flow resistive loads, 5 cm H2O/L/sec (IR5) and 14 cm H2O/L/sec (IR14). With IR5 (6 subjects), the P0.15 response was decreased in two subjects, unchanged in two, and increased in two; peak EMGdi was unchanged in all, while rate of rise of EMGdi response decreased in 4 of the 6 subjects. With IR14 (6 subjects, 9 runs), the P0.15 response was not decreased in any subject, remained unchanged in 4, and increased in 5; peak EMGdi response to rebreathing in all runs was, again, unchanged by this load, but rate of rise of EMGdi was decreased in 3 and unchanged in 6. The inspiratory off-switch threshold as reflected by peak diaphragmatic activity was not changed by inspiratory flow resistance, whereas inspiratory neural drive as reflected by the the rate of rise of activity was decreased in some subjects. The decrease in inspiratory drive without change in inspiratory off-switch threshold resulted in prolongation of inspiration in an attempt to effect efficient lung expansion. However, the defense of ventilation during rebreathing with both resistances appeared to mainly depend on the response of inspiratory muscle force (P0.15), since in 7 of the 7 runs in which the P0.15 response was significantly increased from control, the ventilatory response was not decreased.

Effects of electrode position on esophageal diaphragmatic EMG in humans

The effects of electrode position and gastric-balloon anchoring on esophageal diaphragmatic EMG (EMGdi) responses to CO2 rebreathing were studied in seven normal sitting humans using an esophageal catheter that consisted of four platinum wire coils enabling simultaneous recording of three EMGdi signals from three different sites in the esophagus. A gastric balloon attached to the distal end of the catheter allowed anchoring of the catheter. EMGdi signals were quantitated as a moving time average. Two rebreathing experiments were performed with and without balloon anchoring on the same day. Changes in electrode position of at least 2 cm above the site of maximum EMGdi activity caused minimal changes in the moving average EMGdi and did not significantly effect the quantitated EMGdi response to CO2 rebreathing. The maximum EMGdi activity was approximately 2 cm above the gastroesophageal junction in sitting humans. Stabilization of the catheter with an inflated gastric balloon did not improve the reproducibility of the EMGdi data. Finally, the EMGdi response to two CO2 rebreathing runs done at the same sitting showed intraindividual reproducibility.

Avulsion of the ureter caused by stone basket manipulation

A case of an iatrogenic loss of 18 cm. of the distal ureter owing to attempted basket retrieval of a lower ureteral stone is reported. The defect was bridged by mobilizing the kidney, constructing a Boari flap and fixing the bladder with a Psoas hitch. The complications of stone manipulating are reviewed and discussed.

Nodular pulmonary sarcoidosis. Clinical, roentgenographic, and physiologic course in five patients

Five cases of nodular pulmonary sarcoidosis are presented. That nodular infiltration represents a reversible stage of sarcoidosis is suggested by the fact that all patients demonstrated roentgenographic resolution of these infiltrates. In four of the five subjects, tests of pulmonary function showed restrictive disease which remained unchanged or worsened despite radiologic clearing, suggesting persistence of active disease or development of residual pulmonary fibrosis. Evidence of obstruction of airways that was unexplained by a history of smoking was present in all of the five subjects.

Disseminated pulmonary blastomycosis in an immunosuppressed patient. Diagnosis by fiberoptic bronchoscopy

A 73-year-old man with malignant lymphoma who was undergoing treatment with systemic chemotherapy presented with an acute, febrile illness associated with cough and sputum production. The patient developed bilateral, diffuse, pulmonary interstitial infiltrates with rapidly progressive respiratory insufficiency. The diagnosis was made by demonstrating Blastomyces dermatitidis in bronchial brush and transbronchial lung biopsy specimens obtained through fiberoptic bronchoscopy.