Pierre H. Beaudry

Immediate and long-term effects of chest physiotherapy in patients with cystic fibrosis

Both the immediate and long-term effects of chest physical therapy administered by a parent were evaluated in eight children with cystic fibrosis. Spirometric and plethysmographic evaluations were performed pre-CPT and at 5 and 30 minutes post-CPT. The pre-CPT measurements after a three-week period with no CPT were compared with the values while receiving CPT on a regular twice daily basis. There was a significant decrease after three weeks without CPT for FVC (P less than 0.025), FEV1 (P less than 0.005), FEF25-75 (P less than 0.005), and Vmax60TLC (P less than 0.025). When the patients had been receiving CPT on a regular basis, the only immediate effect was an increase in PEFR after 30 minutes post-CPT (P less than 0.05). After three weeks without CPT, there were increases at 30 minutes post-CPI for FVC (P less than 0.005) and Vmax60TLC (P less than 0.05). These findings indicate that although there may be little immediate functional improvement when CPT is received on a regular basis, a three-week period without CPT leads to a worsening of the functional status, which is reversed with renewal of regular CPT.

Nocturnal home oxygen in the treatment of hypoxemic cystic fibrosis patients

The effect of nocturnal oxygen therapy on mortality and morbidity rates and on progression of disease was tested in a double-blind, randomized trial of 28 subjects with advanced cystic fibrosis. Patients were selected on the basis that their awake arterial oxygen tension was less than 65 mm Hg when they were clinically stable. Oxygen was prescribed in 1 L/min increments to obtain an awake arterial oxygen tension of greater than or equal to 70 mm Hg. Subjects received humidified oxygen or room air from modified concentrators. They were enrolled over a 3-year period and followed for an average (+/- SD) of 26 +/- 9 months. The average number of hours per night of concentrator use was 5.3 +/- 3.2 hours in the air group and 7.0 +/- 1.9 hours in the oxygen group. Over the follow-up period there were four deaths in each group, and oxygen therapy had no significant effect on the frequency of hospitalizations. Progression of disease was ascertained from nutritional status, pulmonary function, blood gas values, exercise ability, and right ventricular ejection fraction response to exercise (as measured by equilibrium-gated radionuclide angiocardiography), and psychologic status was measured by standardized tests of mood, self-esteem, and cognitive function; group comparisons for the first year revealed no significant differences; however, school or work attendance was maintained in the oxygen group but deteriorated in the air group. Clinical signs of cor pulmonale were documented during follow-up in 10 patients in toto, and all lived at least 9 months from the onset of these signs. The lack of association between the onset of these signs and imminent death, or the usefulness of measurements of the maximal oxygen uptake during progressive exercise and the right ventricular ejection fraction response to exercise as prognostic indicators, suggest that death may not be the result of cor pulmonale. We conclude that nocturnal oxygen treatment in patients with cystic fibrosis did not appear to affect mortality rates, the frequency of hospitalizations, or the progression of disease; oxygen use should be instituted only after the development of symptoms related to hypoxemia.

Is anti-Pseudomonas therapy warranted in acute respiratory exacerbations in children with cystic fibrosis?

A controlled study was designed to clarify the indications for antibiotic therapy in children with advanced cystic fibrosis hospitalized with respiratory exacerbations. Twenty-two children with severe CF and signs of acute lower respiratory infection were randomly assigned to receive either cloxacillin or carbenicillin plus gentamicin administered intravenously for ten days. Other aspects of therapy were constant. The groups were comparable in all respects and Pseudomonas aeruginosa was the predominant sputum pathogen in most patients. Clinical improvement, chest radiograph changes, evidence of airway obstruction, and bacteriologic flora of sputum were no different regardless of the regimen used. These results suggest that the use of anti-Pseudomonas medication in these children may not always be necessary. These observations need to be confirmed by blind-controlled studies in larger numbers of patients with mild as well as severe respiratory involvement.

Long-term pulmonary sequelae of premature birthwith and without idiopathic respiratory distress syndrome

Seven children born prematurely who survived the respiratory distress syndrome, seven children born prematurely who had no neonatal lung disease, and seven normal children born at term were studied by comparison of flow volume curves obtained while breathing air to those obtained while breathing 80% helium and 20% oxygen. Expiratory flow rates in air both groups of prematurely born children were lower than flow rates of the children born at term, and the volumes of iso-flow were higher in the survivors of RDS than those of the children born at term. The differences in flow rates in air suggest an increase in large airway resistance in both groups of prematurely born children. It is speculated that this may be secondary to growth retardation related to prematurity. The elevated Viso V in the RDS group suggests an increase in small airway resistance secondary to the disease or to its therapy.

Birth weights of infants of toxemic mothers

Summary A comparative study of the birth weights of infants of toxemic mothers and of nontoxemic control infants was conducted at the Cincinnati General Hospital. The data were analyzed, and weight at birth and calculated gestational age at time of delivery were correlated. Contrary to what is generally believed, and has often been reported, the birth weights of the toxemic group were not lower than those of the control group. Indeed, the toxemic infants were larger than the control infants, though the weight difference was not statistically significant. The comparison of the correlation between birth weight and gestational age emphasized the fact that the two groups did not differ from one another.

Long-term pulmonary sequelae of theWilson-Mikity syndrome

Five children born prematurely, eight to ten years ago, who survived the Wilson-Mikity syndrome were compared with six apparently normal prematurely born children and eight normal children born at term, by means of flow volume curves obtained while breathing air and while breathing a mixture of 80% helium and 20% oxygen. The flow rates in air of the group who survived the Wilson-Mikity syndrome were significantly lower than those of the prematurely born normal children (P less than 0.01), and than those of the eight normal children (P less than 0.001). The volume of isoflow while breathing air compared to that while breathing HeO2 was highly variable, but not significantly different in the three groups. Three of the five survivors of the Wilson-Mikity syndrome had a marked concavity in the shape of their flow volume curves. It is concluded that these abnormalities are due to focal increases of compliance or resistances or both of terminal lung units and result in adjacent areas of the lung emptying at different rates. The relationship between physiologic and anatomic abnormalities seen at autopsy in those who die to the disease suggests that they are due to the same pathologic process. Whether or not these abnormalities will disappear with future lung growth remains to be seen.

VALUE OF AIR AND HELIUM-OXYGEN FLOW-VOLUME CURVES IN DETECTION OF EARLY SMALL AIRWAY DISEASE IN CYSTIC FIBROSIS (CF)

To assess early small airway disease in CF patients with minimal pulmonary involvement, maximal expiratory flow volume (MEFV) curves were obtained while the children were breathing first air and then an 80% helium - 20% oxygen gas mixture. Fifteen CF patients and 24 normal children were studied. Maximal flow rates (Vmax) at 50 and 25% vital capacity (VC) were calculated from the air and helium-mixture MEFV curves and compared to give flow ratios (helium Vmax/air Vmax) at these lung volumes. At 50% VC, the helium/air ratios were similar in CF patients and normal subjects. At 2S% VC, the ratio was significantly lower (p<0.05) in the CF patients. The air and helium MEFV curves from each subject were superimposed and the point where the curves crossed (point of identical flow-PIF) determined and expressed as % VC. For the CF patients, the mean PIF was 18.3% VC and for the controls, 4.9% VC (p<.001). Nine of the 15 CF patients had PIF values greater than 2 S.D. from the normal mean. None of the following tests were abnormal in more than 3 patients: FEV1/FVC, MMEF, RV/TLC and Vmax 25 and 50% TLC. Closing volumes were normal in all patients. Determination of the PIF appears to be a simple, noninvasive, and sensitive test for the detection of early small airway involvement in CF.

A trial of SA-97 in the treatment of asthma in children.

Abstract Thirteen trials of SA-97 were carried out on 10 children with chronic asthma. The trials varied from 3 to 45 weeks in duration and the children were on a variety of maintenance therapies which were maintained constant throughout the control and trial period of the drug. The effect of the treatment was assessed by the use of objective measurements of ventilatory function before and after the use of an Adrenalin aerosol. In 10 trials there was an increase in the indirect MBC test during the period of SA-97 therapy of 10 per cent or more above the value during the control period. There was deterioration of this order in one subject. Responsiveness to Adrenalin aerosol was unaffected by SA-97. The effects of SA-97 and Adrenalin aerosol appeared to be additive rather than synergistic.

Assessment of Ventilation-Perfusion Inequality by aADN2 in Newborn Infants

The contribution (Qo/Qt) of gas-filled air spaces with reduced ventilation-perfusion ratio (VA/Qc) to the production of total venous admixture in nondistressed premature infant and newborn infants with transient tachypnea was assessed by the aADN2 and AaDo2. The mean value for Qo/Qt in both nondistressed prematures and infants with transient tachypnea was 0.08. In both groups this represented about 30% of total venous admixutre.

1637 VENTILATION, RESPIRATORY CENTER OUTPUT AND CONTRIBUTION OF THE RIB CAGE AND ABDOMINAL COMPONENTS TO VENTILATION DURING CO2 REBREATHING IN CHILDREN WITH CYSTIC FIBROSIS (CF)

We investigated the respiratory response of CF patients to CO2 under hyperoxic conditions. Using a standard CO2 Read rebreathe technique, we studied 14 CF patients with mild to severe degrees of airway obstruction. We evaluated their response to CO2 in terms of their ventilation (VE), mean inspiratory flow rates (VT/Ti) and their occlusion pressures (P.1). In order to understand the contributions of the rib cage and abdominal components to ventilation (Vrc and Vab) we assessed the volume change in each compartment by the use of magnetometers. We found that, when normalized for the height of the child,the slope of VE vs end tidal CO2 (PETCO2),as well as the slope of VT/Ti vs PETCO2 correlated significantly with the forced expiratory flow between 25 and 75% of vital capacity (FEF25-75)(r=.78,p <.001 and r=.74, p<.01 respectively).The values for P.1 were within the normal range and did not correlate with the FEF25-75. The contribution of Vrc to the increases in VT with increasing VE was double that of Vab.The increasing Vrc correlated with the increasing VT (r=.88,p<.001).This predominance of Vrc is similar to that seen in normals. In conclusion, we have shown that tests involving a mechanical response to CO2 correlate with the FEF25-75. There is no evidence of abnormalities in the control of breathing.