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PubMed1979

[Oscillatory determination of functional residual capacity (FRC)].

The washing-in of a low density gas (80% He, 20% O2) into the lung is being eased by greater diffusibility and diminished work of breathing. Helium analysis was performed by means of the oscillation method with an equipment suitable for the assessment of resistance to breathing. The density of helium gas mixture is being compared to the density of ambient air.

Functional Residual Capacity↗
PubMed1978

Functional residual capacity and body position in the dog.

Resting lung volumes in the supine position (FRCs) were determined by N2 washout method in 67 dogs under pentobarbital anesthesia and computed in ml/kg body weight (BW). In 21 other dogs, FRCs and the change in FRC from the supine to upright positions (deltaFRC) were determined; these lung volumes were expressed in ml/kg BW and in percentage of TLC40 (lung volume at 40 cmH2O positive-pressure inflation). It was found that a) FRCs averaged 38.6 plus or minus 8.2 and 42 plus or minus 5.9 ml/kg BW in the two groups of dogs; b) deltaFRC averaged 23 plus or minus 4 ml/kg BW resulted in large data dispersion, a large coefficient of variation (CV) and a poor correlation (r) of lung volume to BW; D) on the contrary, marked uniformity of FRCs and FRCu (upright FRC) was obtained by expressing the resting lung volumes in %TLC40, allowing an accurate prediction of FRC from the inspiratory capacity (IC). Relationship of FRCu to TLC was comparable to human data reported in the literature. FRCs (%TLC40) was smaller than values previously reported for awake human subjects, probably due to the FRCs reduction in our dogs by anesthesia.

Animals↗
PubMed1975

The effect of artificial ventilation on functional residual capacity and arterial oxygenation. II. Comparison of spontaneous respiration and artificial ventilation at similar arterial carbon dioxide tensions, tidal volumes and inspiratory gas flow rates.

We have compared cardiac output, gas exchange and pulmonary mechanics during spontaneous breathing and artificial ventilaton under conditions which kept PaCO2 within the normal range and maintained constant tidal volume and inspired gas flow rate. In dogs anaesthetized with pentobarbitone and ventilated with air, artificial ventilation increased VD/VT but did not reduce Q angstrom, FRC, or CL. PaO2 increased and A-aDO2 decreased during aritificial ventilation, perhaps because of a small increase in Q angstrom and a small decrease in oxygen consumption. It appears that many of the reported deleterious effects of artificial ventilation may be due to the use of other anaesthetic agents and patterns of ventilation, and to changes in PaCO2.

Anesthesia↗
PubMed1975

Lung volumes and closing capacity with continuous positive airway pressure.

Total lung capacity, vital capacity, residual volume, and functional residual capacity were determined by body plethysmography and the single-breath oxygen (SBO2) test was performed at 0, 5, and 11 cm H20 continuous positive airway pressure in healthy, awake, seated, spontaneously breathing subjects. Mean values for the absolute lung volume at which phase IV of the SBO2 test begins (closing capacity) did not change significantly with continous positive airway pressure at 5 or 11 cm H2O. Mean total lung capacity, functional residual capacity, and residual volume increased significantly, and the mean closing volume, the lung volume above residual volume at which phase IV begins, decreased significantly with 11 cm H20 continuous positive airway pressure; differences at 5 cm H20 were not significant. The slope of the alveolar nitrogen plateau (phase III) obtained during the SBO-2 test did not change with continuous positive airway pressure.

Adult↗
PubMed1975

Lung volumes in scoliosis before and after correction by the Harrington instrumentation method.

Studies of static lung volumes were performed before and after surgery in 92 scoliotic patients, aged 10 to 25 years. The majority of the patients had idiopathic dorsal curves. Vital capacity, total lung capacity, functional residual capacity and residual volume were measured at least 18 months after surgery. A significant increase was observed in all static volumes, averaging 10 per cent; the pre- and postoperative values were expressed in per cent of predicted normal values according to age and height. Correction of body height was taken into consideration in the prediction of normal values. Patients with the more advanced scoliosis had the greatest improvement in lung volumes. The patients were treated postoperatively with a Milwaukee brace for an average of 15 months. The use of this brace, which allows for chest expansions, might account for the improved lung function compared to previous series where plaster body jackets were used. Thus the correction of idiopathic scoliosis by the standard posterior fusion with Harrinton instrumentation together with our postoperative routine provides a lasting reduction of the spinal deformity, prevents progression of respiratory impairment and, in fact, increases the lung volumes, vital capacity, total lung capacity and functional residual capacity by an average of 10 per cent.

Adolescent↗
PubMed1992

Cardiopulmonary function during 10 days of head-down tilt bedrest.

Pulmonary and cardiovascular responses to simulated weightlessness, i. e. 6 degrees head-down tilt bedrest (HDT) were investigated in six healthy male volunteers (mean age 26 yrs). Pulmonary diffusing capacity, functional residual capacity, pulmonary capillary blood flow, and lung tissue volume were measured by inert gas rebreathing. Heart rate and mean arterial blood pressure were obtained from finger blood pressure readings using a plethysmographic technique (Finapres). The short-term (20 min) response to HDT consisted of a 22% increase in pulmonary blood flow, and 13% and 31% falls in blood pressure and heart rate relative to standing. Functional residual capacity fell by 33%, while lung tissue volume increased insignificantly. Subsequent measurements during 10 days of HDT and 5 days of recovery revealed no further changes in lung volume, lung tissue volume, or blood pressure. However, diffusing capacity fell gradually and remained 4%-5% below baseline values after the 7th day of bedrest and during recovery (p less than 0.05). Pulmonary blood flow decreased by 16% during head-down bedrest and recovered partially within the following 5 days (p less than 0.05). We conclude that during and after simulated weightlessness marked alterations in cardiovascular function and marginal affections of gas exchange can be demonstrated already at rest. They may be considered as contributing factors to orthostatic and exercise intolerance observed after space flight.

Adult↗
PubMed1992

Structural change of the thorax in chronic obstructive pulmonary disease.

This study examines structural changes of the thorax in hyperinflated subjects with chronic obstructive pulmonary disease (COPD). Age-matched normal subjects were used for comparison. Thoracic dimensions were determined using anteroposterior and lateral chest radiographs performed at total lung capacity, functional residual capacity, and residual volume. Rib cage dimensions (lateral diameter, rib angle, anteroposterior diameter) and diaphragm position were determined at each lung volume. There were no significant differences in rib cage dimension between the COPD and normal subjects for all lung volumes. In contrast, the diaphragm was significantly lower in the COPD subjects. The change of rib cage dimensions in the COPD subjects (for a similar volume change) was not different from that in normal subjects, whereas the change of diaphragm position in the COPD subjects (for a similar volume change) was reduced. In conclusion, the primary structural change of the thorax in COPD with chronic hyperinflation is confined to the diaphragm, with no appreciable structural change in the rib cage.

Aged↗
PubMed1979

Lung function in children with recurrent bronchitis.

Lung function was studied in 29 children suffering from recurrent bronchitis (average number of bronchitis attacks per year: 4.2 +/- 0.5). Most of them (73%) were 1--7 years old. The date of exploration in relation to the last acute bronchitis was on average 6 weeks. Lung mechanics, residual functional capacity, blood gases and regional lung function were measured. Most of the children were suffering from some kind of functional disorder; alteration of lung mechanics -- increase of lung resistance (22/29) decrease of dynamic compliance (15/23); increase of functional residual capacity (6/10), non specific bronchial hypersensitivity (12/17); regional ventilatory and perfusion malfunction. These functional disorders could be the first evidence of the bronchial lesions which cause chronic obstructive bronchitis in adults.

Bronchitis↗
PubMed1976

Pulmonary function studies after smoke inhalation.

Pulmonary function studies were performed within 72 hours of injury in seven patients with smoke inhalation injury diagnosed by positive 133Xe scintiphotographs and in eight patients with burns of similar size but with negative 133Xenon scans. The former patients showed decreased peak flow, decreased flow at 25, 50, and 75 per cent of vital capacity, and an elevated pulmonary resistance. In addition, single breath nitrogen tests revealed evidence of maldistribution of ventilation/perfusion abnormalities. Total lung capacity, functional residual capacity, and compliance (both dynamic and static) were similar in the two groups. Pulmonary function studies can be of assistance in evaluating smoke inhalation, estimating the severity, and following the course of patients with this disorder.

Adolescent↗
PubMed1977

Acute supine respiratory failure due to bilateral diaphragmatic paralysis.

This report documents the first known case of bilateral diaphragmatic paralysis following blunt trauma to the chest. The important role of diaphragmatic function in maintaining ventilation, particularly with the patient in the supine position, is illustrated by the reduced total lung capacity, functional residual capacity, and vital capacity. Severe hypoxemia with the patient in the supine position, was markedly improved by elevation of the patient to 30 degree and was further improved by sitting the patient upright. Following an initial period of acute respiratory failure, the patient was managed acceptably by maintaining an elevated position for sleeping until diaphragmatic function returned, about nine months after the injury.

Accidents, Traffic↗
PubMed1979

Serum factor in cystic fibrosis: correlation with clinical parameters.

The relationship between the activity of the cystic fibrosis serum ciliary dyskinesia factor, detected by the rabbit tracheal bioassay, and clinical status of the patient has been investigated in children, 1-24 years old, with cystic fibrosis. No significant correlation was found between the amount of serum factor activity and age, clinical status assessed by the Schwachman score, pulmonary function (vital capacity, functional residual capacity, total lung capacity, residual volume, maximum breathing capacity, maximal midinspiratory flow, and maximal midexpiratory flow) or blood gas levels (pCO2, pO2). The activity showed no significant relationship to serum galactosyltransferase activity in children with cystic fibrosis.

Adolescent↗