Douglas N. Crozier

Perspectives in Cystic Fibrosis

Sex differences, age at diagnosis, type and severity of symptoms at presentation, pulmonary function, and radiologic findings are prognostic factors that enable the clinician to place patients in various risk groups. The definition and characteristics of these groups will aid in the assessment, counseling, and follow-up of patients with cystic fibrosis.

Cystic Fibrosis: A Not-So-Fatal Disease

Cystic fibrosis is an intricate disease involving the whole patient and requiring complicated treatment. Staph. aureus must be eradicated from the lungs and reinfection prevented; gram-negative organisms are treated when they become pathogenic. Pancreatic insufficiency requires adequate enzyme replacement therapy, and •attention to nutrition is mandatory.

The Correlation of Radiological Changes with Pulmonary Function in Cystic Fibrosis

Abstract To determine airway resistance and degree of obstruction in cystic fibrosis, the authors measured vital capacity, maximum midexpiratory flow rate, diffusing capacity, and hypoxemia. Dead space to tidal volume ratios were used as an index of imbalance between ventilation and perfusion. Chest films were assessed independently for air trapping, bronchial wall thickening, cyst formation, retained secretions within the cysts, and overall extent of disease. One hundred and ten scores were obtained in 69 patients, and an excel ent correlation was found between abnormality in pulmonary function studies and roentgeno ogically detected pulmonary disease.

Cor pulmonale in cystic fibrosis.

A VCG and an orthogonal ECG were done on 66 ambulatory patients with cystic fibrosis. Arteriolized pO2, FEV1/VC and MBC were related to electrocardiographic measurements. In this group of adolescent and young adult patients the most helpful electrocardiographic sign of cor pulmonale is a low voltage representing the left ventricle. The four best indicators from the cardiogram are (1) Rx less than .8 mv; (2) Rx/Sx less than 4.0; (3) Tx less than .4 mv; and (4) MLVF + MLVH less than 2.5 mv. If more than one indicator is found cor pulmonale is likely present. Increased voltage over the right ventricle does not identify patients with cor pulmonale.

VENTILATORY MUSCLE TRAINING IN CYSTIC FIBROSIS

Ventilatory muscles (VM), like other skeletal muscles, can fatigue, and respiratory failure can result from inadequate VM power to overcome increased respiratory loads. Improving VM endurance may benefit chronic lung disease patients by making these muscles less susceptible to fatigue. Four Cystic Fibrosis (CF) subjects, with mean FEV1 68±12% predicted, participated in a specific VM endurance training program consisting of 25 min/day maximal normocapnetc ventilation 5 days/week for 4 weeks. They improved their VM endurance 51.6± 18.8 % (P< 0.02). Seven CF subjects, with mean FEV1 67±13 % predicted, participated in a 4-week physical activity training program consisting of 1 ½ hours/day of swimming and canoeing, without specific VM training. They increased their VM endurance 56.7±26.7 % (P <0.005). However, four normal subjects, on the same specific VM training program, increased their VM endurance only 22.1±7.3 % (P<0.005). The increased response of the CF subjects to training suggests either that they had reduced VM endurance initially, or that the training program superimposed on their increased respiratory load was a greater training stress. We conclude from these results that VM endurance can be rapidly improved in CF patients. Furthermore, a rigorous program of upper body endurance exercise is equally effective in improving VM endurance as specific endurance training.

REDUCED LEFT VOLTAGE IN THE VECTORCARDIOGRAM AS AN INDICATOR OF COR PULMONALE IN CYSTIC FIBROSIS

Recognition of right ventricular hypertrophy in cystic fibrosis has been difficult. 74 cases of cystic fibrosis were studied with arterialized finger prick blood for pO2, a series of static and dynamic pulmonary function tests and vectorcardiograms (Frank lead) and orthogonal X,Y,Z all done the same day. Group I: normal pO2 for age (N=31). Group II: pO2 less than two standard deviations for age (N=43). There was no significant correlation between the S wave in the X lead or the maximum voltage to the right in frontal or horizontal loops (signs of right ventricular hypertrophy) and the pO2 or selected respiratory function tests in either group. We were surprised to find that there was a significant positive correlation in group II of (1) R in lead X(Rx) with pO2 (r=.38), FEV1.0 (r=.44) MBC (r=.39), (2) frontal plane maximum left voltage (FMLV) with pO2 (r=.40) FEV1.0 (r=.37) MBC (r=.36), (3) T in the X lead (Tx) with pO2 (r=.37) and MBC (r=.47).Conclusions: As the respiratory function tests worsen or the pO2 lessens the voltage over the left ventricle gets less. These simple hand measurements of left voltage (Rx, FMLV, and Tx) can be used to follow patients with cystic fibrosis to detect the development of cor pulmonale.