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Biomedical subjects

M C Kallay

Publications and source records attributed to M C Kallay.

29 records · Page 2Linked to original sources
PubMed1986

Value of chest ultrasonography versus decubitus roentgenography for thoracentesis.

Chest ultrasonography (CU) has been advocated as an effective tool for diagnosis and localization of pleural fluid. Studies to date supporting the technique have been anecdotal and nonrandomized. To determine if CU was beneficial when thoracentesis was performed by clinicians or house staff, we evaluated prospectively 205 patients presenting with pleural effusion at 2 community teaching hospitals. Decubitus roentgenograms were obtained on all patients, but CU with targeting by skin marker was performed on a randomized basis. Results were evaluated as to (1) whether the quantity of fluid obtained was sufficient for the intent of the procedure, (2) the number of needle insertions required to obtain the fluid, and (3) the incidence of complications such as pneumothorax. One hundred three effusions were evaluated by CU and 102 by roentgenography alone. The effusions in each group were stratified as small (obliteration of less than half of the hemidiaphragm on roentgenogram) or large. Small effusions were further stratified as free flowing or loculated (no layering of fluid on decubitus roentgenograms). By chi-square test, CU was significantly superior to decubitus roentgenograms alone for obtaining adequate fluid samples in small effusions (p less than 0.01). This was true regardless of whether the effusion was loculated (p less than 0.02) or free flowing (p less than 0.05). The technique had no such advantage in large effusions. We did not find that CU significantly reduced the need for multiple attempts nor incidence of complications in any group.

Drainage↗
PubMed1986

Predictors of mortality in the immunocompromised patient with pulmonary infiltrates.

To determine predictors of mortality in immunocompromised patients with pulmonary infiltrates, we reviewed the records of all such patients admitted to two community teaching hospitals who underwent a lung biopsy over a ten-year period. We examined the consequences of advancing age, primary disease, fever, neutropenia, immunosuppressive corticosteroid therapy, previous lung radiation, roentgenographic pattern, result of lung biopsy, room air arterial oxygen pressure (Pao2), early mechanical ventilation, and the presence of a comorbid disease on eventual outcome. We identified 104 episodes in 99 patients. Sixty-seven (64%) survived and 37 died. By both discriminant analysis and logistic regression statistical methods, mechanical ventilation, the initial room air Pao2, and corticosteroid therapy were the dominant independent variables, in that order, to significantly predict mortality. No patient survived who simultaneously had a room air Pao2 less than or equal to 50 mm Hg, was on corticosteroids, and was mechanically ventilated. Eighty-three percent of survivors had either none or, at most, one of these three variables present. We conclude that hypoxia, immunosuppression by corticosteroids, and the necessity for mechanical ventilation within 72 hours of hospitalization indicate a poor prognosis in the immunocompromised patient with pulmonary infiltrates who has undergone a lung biopsy.

Adolescent↗
PubMed1985

Effect of the rebreathing pattern on pulmonary tissue volume and capillary blood flow.

Noninvasive rebreathing measurements of pulmonary tissue volume (Vt) and pulmonary capillary blood flow (Qc) theoretically and experimentally vary with the rebreathing maneuver. To determine the cause of these variations and identify ways to minimize them, we examined the consequences of varying the volume inspired (VI), rebreathing rate (f), volume rebreathed (Vreb), and alveolar volume (VA) on the observed Vt and Qc in six normal sitting subjects. When VA was increased by progressively larger VI and Vreb, Vt increased 50 ml/l of VA. Increasing VA while keeping VI and Vreb constant did not significantly alter Vt. Diminishing Vreb while VA and VI constant caused Vt to fall 108 ml/l decrease in Vreb. Therefore the observed Vt is not simply a function of VA but increased with greater penetration of the inspired gas into the lungs. Diminishing f from 40 to 12 breaths/min caused the observed Vt to rise 27%, indicating time allowed for alveolar mixing is an important determinant of Vt. The observed Qc, in contrast, was essentially independent of the same variations in rebreathing. The above findings were similar regardless of solubility of the tracer gas (dimethyl ether instead of acetylene) or changing to the supine position. A two-compartment series lung model derived from the anatomy and rates of gas mixing in normal human pulmonary lobules produced similar changes in Vt. Thus the degree of uneven distribution between ventilation, VA, Vt, and Qc within the normal lung lobule can account for variations in the observed Vt with different ventilatory maneuvers. Slow deep breathing maneuvers tended to reduce variations in Vt. Unlike Qc, the observed value of Vt can be expected to vary substantially with pathological processes that alter pulmonary gas distribution.

Acetylene↗
PubMed1984

The protective effect of methylprednisolone on carbachol-induced bronchospasm.

We studied the effect of acute treatment with methylprednisolone in 12 asthmatics not dependent on steroids. Carbachol challenge was performed according to a standardized method. Baseline measurements of forced expiratory volume in one second (FEV1), specific airway conductance (SGaw), the provocative dose of carbachol for a 20% decrease in FEV1 (PD20), and that for a 35% decrease in SGaw (PD35) were established. Thereafter, patients returned for retesting at 2, 4, and 6 wk. Prior to each visit, the patients received 1 of 3 treatments: placebo, low-dose (32 mg) methylprednisolone, or high-dose (128 mg) methylprednisolone given orally and distributed in a randomized double-blind fashion. Blood levels confirmed compliance in all subjects. All subjects remained stable throughout the study, with intrasubject FEV1 values agreeing within 5% at the start of each session. The pairwise differences for low-dose methylprednisolone versus placebo were significantly different for both PD20 (p = 0.0004) and PD35 (p = 0.0068). The pairwise differences for high-dose methylprednisolone versus placebo were also significantly different for PD20 (p = 0.04) and PD35 (p = 0.0034). Blocked comparisons of the 2 different methylprednisolone doses were not significantly different. We conclude that methylprednisolone has a protective effect on carbachol-induced bronchospasm, and that this effect is not dose-related at the two doses studied.

Adult↗
PubMed1984

Predicting risk of pneumothorax in needle biopsy of the lung.

We prospectively studied results of 103 consecutive transthoracic needle biopsies of lung lesions suspicious for malignancy to determine if lesion size, depth within the lung, hyperinflation, second needle passes, or 100 percent oxygen breathing influenced the incidence of pneumothorax. Thirty-eight patients (37 percent) developed pneumothorax. Ten (10 percent) required tube thoracostomy for re-expansion. Five of the ten requiring the chest tube had clinically severe obstructive lung disease. In all patients, greater depth (D) in centimeters of needle penetration significantly increased the probability (p) of pneumothorax (p much less than .001) and can be estimated by the equation: (formula see text) The estimated probability of pneumothorax is 13 percent at 1 cm, 49 percent at 4 cm, and 86 percent at 7 cm. An increase in total lung capacity above predicted added additional risk of pneumothorax (p less than .02). Oxygen breathing did not significantly reduce the incidence of pneumothorax, but may reduce size by increasing the rate of reabsorption. The other factors had little influence. We conclude that the more central location of the lesion and pre-existing lung hyperinflation determine the risk of pneumothorax.

Adult↗
PubMed1984

Sensitivity, specificity, and predictive values of closed pleural biopsy.

To determine the clinical value of a nonspecific pleural biopsy specimen and fluid in malignant neoplasm and tuberculosis, we retrospectively reviewed records of all patients with pleural effusions undergoing the procedure at three community hospitals over six years. Two hundred eleven patients underwent biopsies. Adequate tissue was obtained in 207. The results were compared with the ultimate clinical and pathologic outcome by follow-up for 12 to 72 months. The initial procedure was diagnostic of malignant neoplasm in 54 patients and granulomatous disease in ten. A nonspecific or normal result was found in 143 (68%). Malignant neoplasms or tuberculosis was eventually established in 30 and excluded in 101 of the 143 patients. In 12 patients, no diagnosis was made. The procedure's sensitivities were 65% (malignant neoplasm) and 90% (tuberculosis). One false-positive result occurred in a patient with nontuberculous granulomatous pleuritis. The specificity and positive predictive value were 99% and 98%, respectively. The negative predictive value was 77%. Closed pleural biopsy with simultaneous fluid analysis is a valuable diagnostic procedure in community hospital patients, but a nonspecific result does not exclude malignant disease.

Adolescent↗
PubMed1982

The forgotten PPD.

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Evaluation Studies as Topic↗
PubMed1982

Heart block and idiopathic pulmonary hemosiderosis.

A young woman with idiopathic pulmonary hemosiderosis (IPH) and advanced heart block below the atrioventricular node requiring pacemaker therapy is discussed. Thirteen years after the onset of IPH she is free of pulmonary symptoms despite having never received steroid or antimetabolite therapy.

Adolescent↗
PubMed1982

Uneven gas mixing during rebreathing assessed by simultaneously measuring dead space.

To evaluate the rate of gas mixing in human lungs during rebreathing maneuvers used to measure pulmonary tissue volume (Vt) and pulmonary capillary blood flow (Qc), we devised a method to determine the dead space during rebreathing (VRD). Required measurements are initial concentration of a foreign inert insoluble gas in the rebreathing bag, first mixed expired concentration, equilibrated concentration, volume inspired, and volume of the first expired breath. In subjects breathing rapidly at 30 breaths/min with inspired volumes in excess of 2 liters, VRD had values three or more times greater than the predicted anatomical dead space (VD). Breath holding after the first inspiration progressively diminished VRD so that after 10-15 s, it approximately equaled predicted VD. VRD measured with helium was smaller than VRD measured with sulfur hexafluoride. The reported degree of uneven ventilation from gravitational forces in normal humans can account for only about one-third of the difference between VRD and VD. These findings support the concept that mixing by diffusion between peripheral parallel airways is incomplete at normal breathing rates in humans and can result in errors as high as 25% in Vt and Qc.

Humans↗