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Biomedical subjects

B E Pennock

Publications and source records attributed to B E Pennock.

At least 37 records · Page 2Linked to original sources
PubMed1983

Nutritional status and lung function in patients with emphysema and chronic bronchitis.

This study compared the nutritional status of patients with emphysema and chronic bronchitis and examined the relationship between lung dysfunction and nutritional depletion in patients with emphysema. There was no evidence of nutritional depletion in patients with chronic bronchitis (n = 4). In contrast, patients with emphysema (n = 14) were somatically depleted. They exhibited lower values for percent ideal body weight (%IBW), arm muscle circumference (AMC), and triceps skin fold thickness (TSF) (p less than 0.05) than did patients with chronic bronchitis. The creatinine height index (CHI) was also lower in this group, but the difference was not significant (p = 0.08). In patients with emphysema, there was a good correlation between the degree of airflow obstruction and of somatic depletion (FEV1 vs %IBW, r = 0.699, p less than 0.001). The single-breath diffusing capacity (DCO) also correlated well with %IBW (r = 0.6052, p less than 0.019). These results confirm that patients with emphysema are frequently nutritionally depleted and suggest that nutritional depletion contributes to lung dysfunction in emphysema.

Aged↗
PubMed1983

A simplified computer report. Towards an understandable pulmonary function test.

We have developed a graphic format for the display of pulmonary function test results. Patient test results appear as a series of horizontal bar graphs. Each bar length is proportional to the test result and is printed over the normal ranges. This format allows rapid recognition of individually abnormal values. We have also grouped bars to create distinctive patterns characteristic of obstructive or restrictive lung disease. A computer program generates a custom form for each patient, displaying the results and ranges only for the specific test performed on that individual. No preprinting of forms is required. Written in the BASIC computer language, this program was designed to be flexible. A change of program parameters requires only minor program modification. In addition, because of its simplicity, our program can be implemented on almost any computer printer.

Computers↗
PubMed1983

Pulmonary function in progressive systemic sclerosis. Comparison of CREST syndrome variant with diffuse scleroderma.

The pulmonary function and chest roentgenograms were evaluated in 88 patients with the CREST syndrome variant of progressive systemic sclerosis (PSS or scleroderma). Seventy-two percent of the patients had abnormal pulmonary function. An isolated decrease in diffusing capacity was the most common abnormality noted, followed by restrictive abnormalities and airway obstruction. Chest roentgenograms revealed interstitial infiltrates consistent with pulmonary fibrosis in 33 percent. When compared to a contemporaneous group of 77 patients with PSS and diffuse scleroderma, patients with the CREST syndrome had similar abnormalities on pulmonary function testing and chest roentgenogram. However, patients with the CREST syndrome had a lower mean diffusing capacity despite a higher mean vital capacity; this combination of findings suggests primary pulmonary vascular disease. Calcified granulomata were identified significantly more often in PSS-CREST patients, while superior rib notching occurred exclusively in patients with PSS and diffuse scleroderma. The CREST variant of PSS is associated with frequent roentgenographic and pulmonary function abnormalities similar to those seen in PSS with diffuse scleroderma.

Adult↗
PubMed1983

Pulmonary function testing. What is 'normal'?

For many years, confusion has existed concerning the normal range for pulmonary function test results. Using statistical guidelines that have been traditionally applied to the interpretation of measured forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), we have redefined normal limits for the most common pulmonary function test values, including those for FVC, FEV1, mean forced expiratory flow during the middle half of the FVC, FEV1 as a proportion of FVC, residual volume, functional residual capacity, total lung capacity, diffusion capacity, maximum voluntary ventilation, and peak expiratory flow. Our goal is to provide a simple and consistent scheme for interpretation of pulmonary function test data. We consider the assumptions used to achieve this simplification to be reasonable, as long as their limitations are understood.

Humans↗
PubMed1982

Acute and long-term ventilatory effects of hyperoxia in the adult sleep apnea syndrome.

Eight adult patients with sleep apnea were studied to evaluate the ventilatory and cardiac effects of hyperoxia on an acute basis. Five patients then used low-flow nighttime oxygen for 30 to 90 days. The results of the acute study showed that for 30-min study periods, the total number of apneas and per cent apnea time (duration of apneas divided by sleep time) decreased significantly from the room air to the oxygen period (207 to 68, p less than 0.05; 41.1 +/- 18.3% SD to 20.5 +/- 14.4%, p less than 0.05, respectively). Also, the apnea-associated slowing in heart rate is blocked by the supplemental oxygen. Three patients receiving oxygen at home decreased their per cent apnea time by greater than 60%. These patients also responded to the acute administration of hyperoxia by a decrease in apnea time greater than 60%. One patient prolonged the apnea time, and one had a minimal positive response, both again reflecting their acute studies. These data suggested that the severe hypoxemia that develops during an apnea in this syndrome has a central ventilatory effect that propagates the apneas and is significantly reversed by hyperoxia.

Adult↗
PubMed1982

Office spirometry.

Explore the source record for details and available documents.

Ambulatory Care↗
PubMed1981

The detection of sleep apnea in the awake patient. The 'saw-tooth' sign.

We studied 21 subjects, 13 of whom had the sleep apnea hypersomnolence syndrome associated with upper airway obstruction during sleep (SAHS-UAO) to determine if "saw-toothing" on the flow-volume loop was significantly associated with the phenomenon of airway occlusion during sleep. A "saw-tooth" pattern was present on the flow-volume loop in 11 of 13 subjects with SAHS-UAO. The presence of saw-toothing correlated with fluttering of tissue that was visualized in the upper airway via the fiberoptic bronchoscope. The specificity of the saw-tooth pattern for SAHS-UAO was 100%. Generalized obesity may indirectly influence the presence of saw-toothing due to deposition of what appeared to be adipose tissue in the pharyngeal walls. Although the number of subjects in this study is small, saw-toothing on the flow-volume loop appears to be an important aid in the diagnosis of SAHS-UAO.

Adolescent↗
PubMed1981

Rapid conversion of pH to [H+].

Sir William Osler described the practice of medicine as "an art based on Science." The authors have artfully simplified a frequently needed clinical calculation, using sequential multiplication and obviating the need for logarithmic manipulation.

Acid-Base Equilibrium↗
PubMed1981

Role of pulmonary edema in the acute pulmonary response to sepsis.

There is evidence that both bronchoconstriction and accumulation of lung water may contribute to the early alterations in lung function following septicemia. Eigher of these may be mediated by blood components. To assess these proposed mechanisms the changes in hemodynamics, pulmonary mechanics, gas exchange, and gravimetric lung water were measured in the first 4 h after Escherichia coli infusion in the anesthetized dog and baboon. These species were selected because of previously demonstrated differences in the response to gram-negative sepsis. Both species developed systemic hypotension and early hypoxemia. The dogs had early transient increases in venous admixture (Qva/Qt) but not shunt or dead space, while the baboon had a more persistent increase in Qva/Qt and a late increase in dead space, Increases in nonelastic resistance and decreases in lung compliance were preceded or accompanied by decreases in the leukocyte count in both species, but the platelet count, fibrinogen, and total hemolytic complement had different changes in the two species. Postmortem lung analysis revealed increased lung weight in both species but the wet weight-to-dry weight ratio was not increased in either species. The fractional water content of the excess lung mass was less than that of whole blood. Histological examination revealed large numbers of extravasated leukocytes in the lungs, which may be sufficient to explain the increase in lung weight. We conclude that pulmonary edema does not play a role in the early pulmonary response to E. coli bacteremia in either species. The physiological changes observed are more consistent with bronchoconstriction.

Animals↗
PubMed1980

Respiratory mechanics and timing during sleep in occlusive sleep apnea.

Six human obese subjects with the sleep apnea hypersomnolence syndrome associated with upper airway occlusion (UAO) were studied during sleep to characterize respiration. Measurements included the timing components of ventilation, pulmonary resistance, flow, and esophageal and gastric pressures before and during UAOs. During the period between UAOs, the resistance progressively increased (9.4-18.1 cmH2O/l(-1) . s, P less than 0.05) as the ventilation decreased (1.82-0.77 l/s, P less than 0.05), but without changes in esophageal pressure swings. During this period, inspiratory time-to-total cycle time decreased (0.42-0.25 s, P less than 0.05) due to expiratory phase prolongation. The apnea began after expiration and terminated on inspiration with the maximal swings in esophageal and gastric pressure near the termination. During the UAO, the respiratory cycle time decreased slightly, but the expiratory pause time was significantly shortened immediately before ventilation. We suggest that the UAO is but one aspect of this syndrome and that a decrease in central nervous system activity diminishes the respiratory drive before the onset of the UAO.

Adult↗
PubMed1980

Respiratory hypersensitivity to Ascaris extract in guinea pigs sensitized by aerosol.

Guinea pigs exposed via the respiratory route to Ascaris suum extract in aerosol form became hypersensitive. The hypersensitivity was detectable by inhalational bronchial provocation testing using a noninvasive plethysmography, by chopped lung histamine release, and by passive cutaneous anaplylaxis. The antibody responsible for the hypersensitivity seems to be directly associated with pulmonary tissue. A locally produced cytotropic pulmonary antibody, probably IgG or IgE may be causal. Histopathology included only a moderate pulmonary eosinophilia. Individual variability in susceptibility to experimental allergic asthma may be controlled by both physiologic and immunologic reactivities.

Aerosols↗
PubMed1979

A noninvasive technique for measurement of changes in specific airway resistance.

A simple noninvasive technique for measuring specific airway resistance (airway resistance X thoracic gas volume) in unanesthetized guinea pigs is described. Specific airway resistances measured by this technique correlated well (r = 0.81) with the resistances obtained using a pleural catheter pressure measurement over a wide range of airway resistances. This range of resistances was generated by exposing the pigs to an aerosolized histamine bronchial challenge. The average specific airways resistance in unchallenged pigs was 1.24 +/- 3.47 cmH2O/s, somewhat lower than found by others, probably reflecting in part our larger pigs and in part some uncertainty in the absolute value of resistance inherent in our measurement technique. This technique is particularly useful in bronchial challenge experiments because of its sensitivity to acute changes in airway resistance.

Airway Resistance↗
PubMed1977

Aerosol administration of fenoterol hydrobromide (Th 1165a) in subjects with reversible obstructive airway disease.

Bronchodilatory and side effects of fenoterol hydrobromide (Th1165a; hydroxyphenylorciprenaline; Berotec) and isoproterenol given by inhalation were compared in a double-blind crossover study involving 20 volunteer subjects with reversible obstructive disease of the airways. Subjects inhaled medications from aerosol canisters containing fenoterol hydrobromide (0.1 mg, 0.2 mg, or 0.4 mg) or isoproterenol (0.15 mg) or an inert placebo propellant in a random sequence of five testing days. All active drugs substantially increased the forced expiratory volume in one second, the mean forced expiratory flow during the middle half of the forced vital capacity, and the specific conductance. The onset of bronchodilation after both fenoterol and isoproterenol was rapid, but the effect from fenoterol lasted much longer, up to eight hours. None of the medications cuased significant tachycardia or hypertension. After inhalation of 0.1 mg of fenoterol hydrobromide, none of the subjects reported nervousness, headache, tremor, or nausea, incontrast with results reported for isoproterenol, higher aerosol doses fo fenoterol, or oral administration of fenoterol. No additional therapeutic benefit was found in the administration of higher doses of fenoterol.

Adolescent↗