Frank Cerny

Prosthetic materials and muscle flaps in the repair of extensive diaphragmatic defects: an experimental study

Relative merits of three methods of diaphragmatic hernia repair were evaluated in growing animals. Twenty-five puppies underwent laparotomy. In four controls, the left hemidiaphragm was incised and sutured primarily. In the remaining dogs, it was partially resected sparing the phrenic nerve. The defects were repaired in six with silastic sheeting, in eight with polytetrafluoroethylene (PTFE; trademark, Gore-Tex), and in seven with a thoracoabdominal muscle flap. Dogs were killed at 1, 4, and 7 months for gross and microscopic evaluation of the repair. Diaphragmatic function was evaluated by inspiratory force against a closed airway and by selective phrenic nerve stimulation (PNS). Serial fluoroscopy was used to evaluate diaphragmatic motion. Grossly the diaphragms in all groups showed compensatory growth. Microscopically the silastic was encapsulated without adherence, while PTFE showed tissue ingrowth. Maximal inspiratory force was equivalent in all groups but selective PNS revealed left-sided impairment in all experimental groups. Fluoroscopy showed paradoxical motion of the diaphragm in the muscle flap group for 1 to 2 months, and in the silastic repair group for 2 to 3 weeks, with near normal motion in the PTFE group for the entire postoperative period. These differences disappeared by 6 months. Prosthetic materials or muscle flaps are all safe for repair of large diaphragmatic hernias. Diaphragmatic growth occurs and the prosthesis remains in place. Physiologic impairment is minimal and not of clinical importance. Use of PTFE may be the preferred method as it develops better tissue incorporation and results in more normal diaphragmatic motion in the critical early postoperative period.

Relief of central airways obstruction following spinal release in a patient with idiopathic scoliosis

Summary. Patients with idiopathic scoliosis are reported to have a restrictive pattern on pulmonary function tests. A case is presented of a teenage girl with juvenile idiopathic scoliosis who had evidence of airways obstruction in addition to restriction on pulmonary function tests (PFT). Examination of flow‐volume loops suggested central airways obstruction. At the time of induction of anesthesia for the initial spinal release surgery, a double‐lumen endotracheal tube could not be passed, despite fiberoptic visualization, because of extreme deviation of the left main‐stem bronchus. Postoperatively, PFT demonstrated improved flows at high lung volumes and normalization of the shape of the flow volume loop.

In vivo effects of theophylline on diaphragm, bicep, and quadricep strength and fatigability

Aminophylline has been demonstrated to increase in vitro contractility in skeletal muscle, including diaphragm. In vivo studies report significant increases in diaphragm contractility in patients with chronic obstructive pulmonary disease but only small increases in control subjects. The present study determined the effects of aminophylline on strength and fatigability in the diaphragm, the biceps brachii, and the quadriceps of normal individuals. Seven healthy subjects were tested with placebo and drug conditions on separate days in a randomized, double-blind fashion. Mean theophylline levels of 15 +/- 2 mg/L SD were maintained by constant intravenous infusion. Strength of the diaphragm was measured as maximum inspiratory pressure. Strength of the biceps and quadriceps were measured isometrically during arm flexion (90 degrees) and leg extension (115 degrees) against an electronic load cell. Fatigue was measured as the decrease in tension during a 30-second contraction and during a 6-minute period of alternating 5-second maximal contraction and 5-second rest. Therapeutic levels of theophylline had no effect on strength or fatigability during a maximal contraction in any muscle group studied.

1635 EFFECTS OF INTENSIVE IN-HOSPITAL THERAPY ON LUNG FUNCTIONS AND EXERCISE TOLERANCE IN CYSTIC FIBROSIS (CF)

There is little information on the objective benefits of inhospital therapy in CF. We, therefore, studied the effects of a 13 day ± 2.6 SD (range 10-18 days) admission on lung functions and exercise capacity in 15 CF patients with moderate to severe disease. Treatment consisted of intravenous antibiotics, postural drainage and exercise therapy. We measured resting vital capacity (VC), residual volume (RV), total lung capacity (TLC), forced expired volume in 1 second (FEV1), specific airway conductance (SG), arterial oxygen saturation (SaO2), and exercise adaptation and tolerance shortly after admission and before discharge. Adaptation to exercise was evaluated by the work capacity (Watts/kg), peak heart rate (PHR), exercise-induced changes in SaO2 and the ratio of PHR to peak W/kg.The results show that our 2-week treatment program brought about significant, objective improvements in lung function, exercise tolerance and exercise adaptation in CF patients.

119 PULMONARY FUNCTION AND EXERCISE RESPONSES IN CHILDREN WITH MITRAL VALVE PROLAPSE (MVP)

A recent report (Zuwallack et al. Chest 76:17, 1979) on 20 adults with MVP showed increased residual volume in 63%, decreased steady state diffusion capacity (DLCO) in 50%, and increased alveolar-arterial O2 gradients in 42%. We evaluated 18 children (mean age 13.52 ± 3.3 SD years) with MVP and no history of lung disease. Lung volumes, forced expiratory flow rates, airway resistance, single breath DLCO, single breath oxygen closing volume and an incremental cycle ergometer exercise test with work loads increasing by 0.3 watts/kg every 3′ were performed. During the last 1′ of each load, heart rate (HR), end-tidal and mixed-expired PO2 and PCO2, minute ventilation, oxygen saturation and blood pressure (BP) were measured. EKG was continuously monitored. Pulmonary function results were normal before and after exercise. Peak work loads, HR, ventilation, oxygen consumption and BP response were all normal; no CO2 retention or O2 desaturation was noted. Four subjects had unifocal premature ventricular contractions at rest, which were abolished with exercise in three. We conclude that children with MVP have normal pulmonary functions and normal cardiorespiratory response to exercise and, therefore, should not be discouraged from exercise based solely on the MVP. The reason for the differences in lung function between children and adults remains unclear.