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Biomedical subjects

H Baier

Publications and source records attributed to H Baier.

At least 55 records · Page 3Linked to original sources
PubMed1986

Unilateral pulmonary hyperinflation from mucus check-valve mechanism.

Mucus plugging of a large airway resulted in the formation of a check-valve mechanism and pulmonary hyperinflation, rather than atelectasis. Fiberoptic bronchoscopy was both diagnostic and curative. The physician should be aware that mucus plugging may have unusual presentations and may mimic other clinical entities.

Adult↗
PubMed1986

Transient ventilatory and heart rate responses to moderate nonabrupt pseudorandom exercise.

Dynamic responses of inspired minute ventilation, CO2 and O2 end-tidal gas fractions, and heart rate were obtained from six normal human volunteers in response to a complex dynamic exercise challenge. Subjects pedalled a chair ergometer at constant frequency. The retarding torque applied to the ergometer pedals was controlled by a low-pass-filtered pseudorandom binary sequence (fPRBS), which provided a complex, nonanticipatory exercise stimulus containing sufficient high- and low-frequency energy to excite the small signal, broadband ventilatory response. The exercise range was chosen to produce a mean level of O2 consumption at or below 50% maximum O2 consumption. Cross-covariant analysis of the fPRBS exercise with breath-by-breath ventilation provided an estimate of the dynamic (impulse) response to exercise, which contained both fast phase 1 and slow phase 2 components. The initial, phase one, hyperpnea occurred within the same breath as the exercise transition and preceded a hypocapnic response. The phase one hyperpnea represented 26% of the total ventilatory response. The secondary, phase 2, hyperpnea was delayed several breaths from the onset of phase 1. It contained slower dynamics and followed a hypercapnic response. Heart rate increased abruptly during phase 1, peaked near the phase 1-to-2 boundary, and then decreased rapidly. The experimental protocol was designed to minimize the subjective response and provide an adequate stimulus for the faster time constants. Results obtained from these experiments were consistent with a nonhumoral induced phase 1 exercise hyperpnea.

Adult↗
PubMed1986

In vivo estimation of tracheal wall water: effects of histamine and carbachol.

Based on double-indicator-dilution principles we developed and validated a new method of measuring water content in the tracheal wall by inscribing time-concentration curves with the inert gas, helium and the water-soluble gas, dimethylether. In the trachea of conscious adult sheep the measurable water volume of the wall over a 15-cm length ranged between 0.50 and 0.70 ml. The tracheal radius calculated from helium volume and known tracheal length ranged between 7.4 and 9.3 mm. The corresponding measurable "water depth" ranged between 63 and 82 microns. Changes in bronchial blood flow had no consistent influence on tracheal water volume. The intravenous injection of histamine (4 micrograms/kg) increased mean water depth to between 122 and 134% of base line (P less than 0.001), whereas the intravenous injection of carbachol (4 micrograms/kg) had no effect on water depth. The production of large amounts of airway secretions produced by carbachol were removed prior to inscription of the indicator-dilution curves. These findings indicate that the double-gas-indicator technique is capable of measuring in vivo the volume of a water compartment in the tracheal wall and that this volume is increased by histamine. This method may be applicable in human subjects.

Airway Obstruction↗
PubMed1986

Sputum examination for the diagnosis of Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome.

The diagnostic utility of sputum examination in patients with Pneumocystis carinii pneumonia secondary to the acquired immunodeficiency syndrome (AIDS) has so far not been determined. Sputum was induced in 43 patients with AIDS or suspected AIDS just prior to fiberoptic bronchoscopy, scheduled because of an unexplained pulmonary infiltrate on a chest radiograph. Pneumocystis carinii pneumonia was diagnosed by sputum examination and/or by a bronchoscopic procedure in 20 patients. Of these, sputum samples were positive for Pneumocystis organisms in 11 (55%) of 20 patients tested, bronchial washings were positive in 11 (79%) of 14 patients tested, brush biopsies were positive in 9 (53%) of 17 patients tested, and transbronchial lung biopsies were positive in 18 (90%) of 20 patients tested. The presence of P. carinii cysts in sputum did not correlate with the presence of alveolar macrophages in sputum nor with the volume of sputum. Sputum examination for P. carinii organisms, employed as a first diagnostic step in patients with AIDS with pulmonary infiltrates, may frequently obviate the need for bronchoscopy.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Vascular and airway effects of endogenous cyclooxygenase products during lung inflation.

The influence of lung inflation on lung elasticity and pulmonary resistance (RL) and on pulmonary and bronchial hemodynamics was examined in five anesthetized, mechanically ventilated adult sheep before and after treatment with the cyclooxygenase inhibitor indomethacin (2 mg/kg). Lung inflation was accomplished by increasing levels of positive end-expiratory pressure (PEEP). Measurements of pulmonary vascular resistance (PVR), bronchial blood flow (Qbr), and RL were obtained with a Swan-Ganz catheter, with an electromagnetic flow probe placed around the carinal artery, and by relating airflow to transpulmonary pressure (Ptp), respectively. Before indomethacin, increasing PEEP from 5 to 15 cmH2O increased mean lung volume (VL) to 135% (P less than 0.01), Ptp to 165% (P less than 0.005), and PVR to 132% (P less than 0.05) of base line and decreased mean Qbr (normalized for cardiac output) to 53% (P less than 0.05) of base line. Mean RL showed a tendency to decrease with a mean value of 67% of base line at 15 cmH2O PEEP. After indomethacin the corresponding values were 121% for VL, 155% for Ptp, 124% for PVR, 35% for Qbr, and 31% for RL. The PEEP-dependent changes were not different before and after indomethacin except for mean VL, which increased less (P less than 0.05) after indomethacin. The failure of indomethacin to modify PEEP-induced changes in RL, PVR, and Qbr was also present when these parameters were expressed as a function of Ptp. These findings suggest that the cyclooxygenase products elaborated during lung inflation reduce lung elasticity but fail to influence airflow resistance and pulmonary and bronchial hemodynamics.

Animals↗
PubMed1985

Bronchial circulation in asthma.

Whereas the anatomical changes of the bronchial circulation in response to a wide variety of congenital and acquired cardiopulmonary diseases have been well described, little is known about its functional response. There is growing evidence that the bronchial circulation plays a major role in the pathophysiology of hyperreactive airway disease. The bronchial vascular system appears to be involved in mediator transport to and from target tissues in the airway wall, in the development of airway wall edema which may contribute to airflow obstruction, and in heat and water exchange in the tracheobronchial tree. Although our current understanding of these functions is rather sketchy, enough is known to outline the contributions of the bronchial, i.e. the systemic circulation to the mechanisms of bronchial asthma.

Animals↗
PubMed1984

Ventilatory drive in normal man during semistarvation.

The effects of reduced caloric intake on ventilatory drive were investigated in normal volunteers. During a ten-day semistarvation period, six subjects (group 1) received parenterally an amino acid solution providing 550 kcal/d sufficient to prevent a negative nitrogen balance. Six subjects (group 2) received in addition a safflower oil solution providing a total caloric intake of 1,100 kcal/d. Hypoxic ventilatory drive was estimated by an index (parameter A) of the relation between minute ventilation (VE) and hypoxia. In group 1, mean values (+/- SEM) of A decreased significantly from 161.5 (+/- 42.0) to 48.9 (+/- 12.0) by day 10 (p less than 0.05), indicating a severe depression of hypoxic drive despite a positive nitrogen balance. In group 2, A did not change significantly (p greater than 0.05) from control values indicating a preserved hypoxic ventilatory drive. In both groups, the slopes of the line relating VE to arterial PCO2 (delta VE/delta PaCO2) did not change significantly during the ten-day semistarvation period consistent with preservation of the hypercapnic ventilatory drive. These data indicate that during periods of starvation, parenteral administration of aminoacids in an amount sufficient to maintain nitrogen balance is inadequate to prevent depression of respiratory control mechanisms unless a minimum daily caloric intake is achieved.

Adult↗
PubMed1983

Incidence of pulmonary barotrauma in a medical ICU.

One hundred seventy-one patients admitted to a Medical ICU and who received treatment for respiratory failure with mechanical ventilation were studied for the development of pulmonary barotrauma (PBT) as manifested by pneumomediastinum, subcutaneous emphysema, or pneumothorax. Fourteen patients (8%; group A) developed this complication; they were younger, had higher maximal peak inspiratory airway pressures (PIP); and higher levels of maximal PEEP. We conclude that for medical patients treated for respiratory failure with mechanical ventilation, the incidence of PBT is 8% and that younger age, higher levels of PIP and PEEP seem to pose an increased risk for developing PBT.

Adolescent↗
PubMed1983

Quantitative gallium scanning in pulmonary sarcoidosis.

Pulmonary parenchymal involvement in sarcoidosis is due to noncaseating granuloma, fibrosis or both. To assess the granulomatous activity in pulmonary sarcoidosis, we performed gallium-67 citrate scans in 41 patients with sarcoidosis and in 13 non-sarcoid patients, who were free of pulmonary disease and served as controls. Gallium score, a measure of gallium accumulation in lung parenchyma, was obtained from the sum of activity indices (ratio of accumulated gallium activity over a chest quadrant and soft tissues of the mid-thigh) from each of the quadrants over the anterior and posterior aspects of the chest. The gallium score in patients with sarcoidosis was significantly higher than the gallium score in controls. The gallium scores in patients with sarcoidosis, with radiographically apparent pulmonary infiltrate were significantly higher than the scores in the patients with no radiographic evidence of pulmonary parenchymal involvement. The gallium scores in patients not receiving corticosteroids were significantly higher compared to patients who were receiving corticosteroids, and furthermore, the gallium scores fell significantly when corticosteroids were initiated. There was a significant correlation between serum angiotensin-converting enzyme (SACE) activity and gallium score. In 11 patients, 27 sequential gallium scans were performed and changes in gallium score correlated well with the changes in SACE activity and clinical assessment. These findings suggest that quantitative evaluation of gallium scans may be useful in assessing granulomatous activity of pulmonary sarcoidosis and following its response to therapy.

Adrenal Cortex Hormones↗
PubMed1983

Surfactant deficiency in rats without a decreased amount of extracellular surfactant.

Low volume ventilation without periodic large inflations leads to diminished alveolar stability and to the accumulation of increased amounts of airway disaturated phosphatidylcholine (DSPC) in large aggregates that sediment at 1,000 g; surfactant in this form lowers surface tension less rapidly than surfactant present in the 1,000-g supernatant fraction. These observations led to the present work in which we tested the notion that alveolar instability may develop in the presence of an undiminished quantity of total airway surfactant, if the amount of surfactant found in the 1,000-g supernatant fraction is diminished. Pulmonary compliance fell and the alveolar-arterial O2 gradient widened in normothermic rats during constant ventilation in the resting tidal volume range, and, in hyperthermic rats (approximately 39 degrees C) similarly ventilated but with the addition of periodic sighs. The total amount of airway DSPC was undiminished in each group, but in each less DSPC was present in the 1,000-g supernatant fraction compared with controls. Alveolar instability and hypoxemia also developed in hyperthermic rats during low volume ventilation without periodic sighs. Although the total amount of airway DSPC was decreased in these rats, enough remained to theoretically form a continuous monomolecular film over the entire alveolar surface at functional residual capacity; however, there was insufficient surfactant in the 1,000-g supernatant fraction to form such a continuous film. These findings demonstrate that the mode of ventilation, and moderate hyperthermia, may lead to decreased alveolar stability despite the presence of normal amounts of airway surfactant, and, by inference, indicate the extracellular form or state of surfactant has an important effect on alveolar stability.

Animals↗
PubMed1982

Survival of patients with cancer in a medical critical care unit.

The records of 40 patients with cancer and 684 patients without cancer admitted to a medical critical care unit were reviewed for the purpose of comparing survival. Patients with cancer had a higher mortality (55%, 22/40) than the patients without cancer (17%, 118/864). Patients with cancer and respiratory failure had a higher mortality (75%, 18/24) than patients without cancer but with respiratory failure (25%, 66/273) and a higher mortality than patients with cancer but without respiratory failure (25%, 4/16). In patients with cancer, the manifestation of respiratory failure as the adult respiratory distress syndrome (ARDS) was associated with a high mortality (86%, 12/14), which was not statistically higher than in patients with cancer with non-ARDS respiratory failure (60%, 6/10) or in patients without cancer with ARDS (65%, 28/43). Patients with cancer but without respiratory failure had a mortality of 25% (4/16). All eight patients with cancer admitted to the hospital because of life-threatening metabolic disturbances survived. In deciding whether to apply critical care techniques to a patient with cancer, the physician should consider the specific nature of the life-threatening illness.

Adult↗
PubMed1981

Evidence for increased permeability in reexpansion pulmonary edema.

Concurrent analyses of the colloid osmotic pressure of pulmonary edema fluid and serum were performed in two patients with reexpansion pulmonary edema. In addition, pulmonary artery wedge pressure was measured during pulmonary edema in one patient. The colloid osmotic pressure of the pulmonary edema fluid was 73 and 81 percent of the serum value. The pulmonary arterial wedge pressure in one patient was within normal limits (8 mm Hg). Reexpansion pulmonary edema appears to be due to increased pulmonary capillary permeability rather than to hemodynamic mechanisms.

Adult↗
PubMed1981

Influence of lung inflation on the cross-sectional area of central airways in normals and in patients with lung disease.

The influence of lung inflation on the cross-sectional area of the trachea and main bronchi was investigated in 2 normal subjects, 2 patients with emphysema, and 1 patient with pulmonary fibrosis. Fiberoptic cinebronchoscopy was used to measure the cross-sectional area of the airways using calibrated small Teflon discs placed on the airway wall as reference. As an estimate of airway compliance at intermediate lung volumes, radial distensibility was defined as the change in cross-sectional area per change in airway pressure minus esophageal pressure divided by the cross-sectional area at functional residual capacity. Both in normal subjects and in patients with emphysema, the radial distensibility was larger in the trachea than in the main bronchi without differences between the right and left main bronchus. The area-pressure curves revealed alinearity and hysteresis in both groups with an increased distensibility in pulmonary emphysema. In a patient with pulmonary fibrosis, the distensibility was decreased by a factor of ten and the area-pressure curve was linear. These observations suggest altered static mechanics of extraparenchymal, intrathoracic airways in patients with pulmonary emphysema and fibrosis.

Adult↗