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Biomedical subjects

T A Dillard

Publications and source records attributed to T A Dillard.

At least 37 records · Page 2Linked to original sources
PubMed1995

Adherence to established guidelines for preoperative pulmonary function testing.

Guidelines for ordering preoperative spirometry have been proposed by GM Tisi (1979) and more recently by the American College of Physicians (ACP). Requests for preoperative spirometries represent a significant portion of all requests for screening spirometry at our institution and utilize significant man-hours of technician time. We determined the percentage of these requests that did not meet the ACP guidelines and characterized why these requests were being generated. We sampled 441 screening spirometries performed by the Walter Reed Pulmonary Function Laboratory over a 4-week period. One hundred thirty-eight (31%) of these were done preoperatively and complete data were available in 135 cases. Patients in the analyzed group had a mean age of 59 years (+/- 14 years), ranging from 20 to 84 years of age. Fifty-two (39%) requests did not meet ACP guidelines. Most of these requests were associated with either normal spirometry (n = 34) or only mild spirometric abnormalities (n = 14). Spirometry revealed severe obstruction in only one case when the request was not indicated. No cases of moderate obstruction, severe restrictive pattern, or possible upper airway obstruction were found in the group of requests in which spirometry was not indicated. Of the requests that did not meet ACP guidelines, 21 met Tisi's broader guidelines. Most of these requests were found exclusively in patients older than 70 years of age (n = 13) and the morbidly obese (n = 4). Of the 31 studies that did not meet either set of guidelines, 25 occurred in asymptomatic, current, or prior smokers. In conclusion, during a 4-week study period at our institution, 39% of preoperative spirometry requests did not meet ACP guidelines. Most of the patients had been referred because of age greater than 70 years, morbid obesity, and a current/prior history of smoking. However, the literature does not support obtaining preoperative spirometry in such patients except for those undergoing only lung resection. We recommend stricter adherence to the ACP guidelines as a means of decreasing the number and cost of unnecessary spirometries being performed.

Adult↗
PubMed1995

Digital clubbing associated with polymyositis and interstitial lung disease.

Clubbing of the fingers is commonly associated with interstitial lung diseases (ILDs). Although ILD occurs in as many as 40% of patients with polymyositis/dermatomyositis (PM/DM), clubbing of the digits has never been reported to occur in patients with PM/DM and ILD. We report the first case of clubbing associated with PM/DM and ILD.

Adult↗
PubMed1994

Pyogenic arthritis complicating varicella infection.

Arthritis has not previously been reported as a complication in adult patients with chickenpox. In pediatric patients, the arthritis that complicates chickenpox is most commonly aseptic but does rarely result from bacterial infection. We report the case of a 21-year-old man who developed acute monoarticular septic arthritis due to Lancefield Group A beta-hemolytic streptococci. Despite the more common viral cause of arthritis in pediatric patients, physicians should not attribute arthritis associated with varicella in adults to a viral cause without diagnostic arthrocentesis.

Adult↗
PubMed1994

Impact of using stated instead of measured height upon screening spirometry.

This study examined the impact of using stated height instead of measured height on predicted normal values and clinical interpretation of screening spirometry in an outpatient referral population. In a prospective fashion, we evaluated 210 patients, 20 to 89 yr of age, referred for spirometry to our pulmonary function laboratory by obtaining both stated height (HTs) and measured height (HTm). The mean difference between stated and measured height progressively increased with age, from 0.80 cm (20 to 29 yr; p = 0.01) to 5.70 cm (80 to 89 yr; p < 0.001). For men and women, use of HTs instead of HTm produced a mean difference for all ages in computing predicted FEV1 and FVC values of 3.9 and 4.3%, respectively. This effect was more prominent in the older age groups (80 to 89 yr, n = 30); mean differences were 11.0% (211 ml) and 11.7% (303 ml), respectively. Use of HTs instead of HTm altered the detection of restriction by reduced FVC in 17 patients and the detection of obstruction by reduced FEV1/FVC ratio in four patients. Use of HTs altered the clinical assessment of severity by FEV1 in 15 of 108 (13.9%) obstructed patients and altered the assessment of severity by FVC in 11 of 32 (34.4%) restricted patients, with older patients more frequently affected than younger patients. We conclude that the use of stated height instead of measured height in the performance of screening spirometry can have significant impact on the calculation of predicted normal values. These discrepancies can potentially influence the clinical interpretation of screening spirometry, affecting the detection of abnormality and the assessment of severity of disease, particularly among older patients.

Adult↗
PubMed1993

Hemodynamic effects of altitude exposure and oxygen administration in chronic obstructive pulmonary disease.

PURPOSE: Cardiovascular events are the leading cause of death during air travel. Because patients with chronic obstructive pulmonary disease (COPD) develop severe hypoxemia at altitude, we sought to determine whether changes in systemic hemodynamics may contribute to health risks during hypobaric hypoxia. PATIENTS AND METHODS: We recorded radial artery catheter blood pressure, cardiac frequency, and cardiac ectopy in 18 men (aged 68 +/- 6 years, mean +/- SD) with severe COPD (forced expiratory volume in 1 second 0.97 L +/- 0.32 L) at sea level, after 45 minutes of steady-state hypobaric hypoxia at 2,438 m in a hypobaric chamber, and after oxygen supplementation at 2,438 m. RESULTS: Mean arterial pressure (mm Hg), systolic blood pressure (SBP), diastolic blood pressure, and pulsus paradoxus during acute hypobaric exposure did not differ from baseline. During oxygen supplementation, SBP declined (p = 0.028). Decreases in pulsus paradoxus and pulse pressure were noted on oxygen (p < 0.05). We found no changes in cardiac frequency. Cardiac ectopy was uncommon; for one subject, ectopy increased with hypobaric hypoxia and decreased with oxygen administration. CONCLUSION: Vasopressor responses to hypoxia do not add to the risk of air travel in patients with severe COPD. Supplemental oxygen may cause beneficial hemodynamic changes in patients with COPD during acute hypobaric exposure.

Aerospace Medicine↗
PubMed1993

Maximum voluntary ventilation. Spirometric determinants in chronic obstructive pulmonary disease patients and normal subjects.

The 12-s maximum voluntary ventilation (MVV) provides an estimate of the ventilatory reserves available to meet the physiologic demands of exercise. Earlier studies established a general relationship between MVV and FEV1. We hypothesized that the resting maximum inspiratory flow rate (MIFR) also serves as a clinically useful predictor of the MVV. A total of 105 subjects, 45 women and 60 men (age 57 +/- 5 yr, mean +/- SD), with expiratory impairment categories of severe (n = 26), moderate (n = 22), mild (n = 18), and normal (n = 39) based on FEV1 (percentage of predicted), comprised the study samples. The ratio MVV/FEV1 averaged 41 +/- 7 overall. The FEV1 correlated with MVV in normal subjects (p < 0.05, r2 = 0.642) and patients (p < 0.05, r2 = 0.787) better than MIFR (p < 0.05, r2 > or = 0.480). MIFR joined with FEV1 in multiple linear regression to significantly improve the description of MVV:MVV L/min = 30.77FEV1 (L) + 5.94MIFR (L/s) - 4.77 (n = 105; p < 0.05, r2 = 0.849). The 95% confidence limits for MVV varied from 90 to 110% of predicted from the equation for this sample. The factors sex and impairment category did not reduce the unexplained variability in MVV after inclusion of FEV1 and MIFR as covariates in ANOVA (p > 0.05). Addition of MIFR to the model with FEV1 produced greater improvement in r2 than PImax. We conclude that MIFR, although secondary in importance to FEV1, is a significant determinant of MVV in patients with COPD and normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1993

Hypoxemia during altitude exposure. A meta-analysis of chronic obstructive pulmonary disease.

A previous study identified spirometric testing as a useful adjunct for estimating PaO2 during altitude exposure in patients with chronic obstructive pulmonary disease (COPD). We sought to examine the validity of this finding by quantitative analysis of recent published reports. We analyzed acute hypoxic exposures from five prior studies involving 71 patients. Across all studies, the change in arterial oxygen tension per unit change in inspired oxygen partial pressure (linear slope, dPaO2/dP1O2) correlated with the preexposure forced expiratory volume in 1 s (FEV1, p < 0.01). The correlation with FEV1 held for values weighted or unweighted by sample size, with rotating deletion of each study from analysis one at a time, and with semilog slope as the dependent variable. A formula derived from the semilog slope relationship with FEV1 gave accurate description of the mean hypoxic response in each prior study and individual responses from one study (n = 18): ln (PaO2alt/PaO2g) = Kn.(PIO2alt-PIO2g). We found that FEV1 modulated the values of kn in this study. We conclude, based on analysis of prior studies, that preexposure arterial oxygen tension and FEV1 both influence the prediction of PaO2 during hypoxic exposures in patients with COPD.

Aged↗
PubMed1992

Inadvertent loss of bronchoscopy instruments in the tracheobronchial tree.

Equipment malfunction is a rare complication of flexible fiberoptic bronchoscopy. We report an unusual example of equipment failure resulting in the inadvertent introduction of a foreign body (the tip of a cleaning brush) into the bronchial tree of a patient during FFB. In addition, we review several other cases in which problems have been caused by malfunction of accessory equipment. Careful inspection of all cleaning and biopsy utensils should reduce the chance of iatrogenically introducing a foreign body from the bronchoscope channel into the patient's airway. We suggest that biopsy forceps are the best retrieval instrument to use when the foreign body involved is a brush or a piece of wire.

Aged↗
PubMed1992

Oxygen supplementation during air travel in patients with chronic obstructive lung disease.

The objective of this study was to quantitate the effects of O2 supplementation by nasal cannula (NC) and Venturi mask (VM) on PaO2 in patients with chronic obstructive pulmonary disease (COPD) during acute hypobaric exposure, simulating a commercial jet aircraft cabin. We conducted a crossover intervention trial in which subjects served as their own controls in an ambulatory outpatient pulmonary disease service of a tertiary care military medical center and a hypobaric research facility. The subjects were a volunteer sample of 18 men with stable severe COPD, not requiring long-term O2 therapy, and uncomplicated by hypercapnea or cardiac disease. Mean age was 68 years, and mean FEV1 was 0.97 L (31.3 percent predicted). We exposed patients to conditions equivalent to 8,000 feet in a hypobaric chamber. Radial artery catheters provided blood samples at ground level and 8,000 feet. O2 was sequentially administered at 8,000 feet by NC at 4 L/min and 24 percent or 28 percent VM. We describe changes in blood gas data from baseline values and between interventions. O2 at 4 L/min NC flow at 8,000 feet caused PaO2 to increase from 47.4 +/- 6.3 mm Hg to 82.3 +/- 14 mm Hg (n = 18), an increase of 34.9 +/- 14.8 mm Hg. Supplementation of O2 by 24 percent VM caused PaO2 at 8,000 feet to increase by 12.7 +/- 3.8 mm Hg. Twenty-eight percent VM caused PaO2 at 8,000 feet to increase by 19.7 +/- 8.2 mm Hg. Changes in PaO2 with 4 L/min NC were greater than those with either VM. The increase with 28 percent VM was greater than that caused by 24 percent VM (p less than 0.05). Compared with ground level, 4 L/min NC increased mean PaO2 by 9.9 +/- 12.6 mm Hg; 24 percent and 28 percent VM did not cause mean PaO2 to increase above ground level values. We describe a range of capability of familiar O2 therapy devices to increase PaO2 to levels that will maintain tissue oxygenation of patients during acute altitude exposure.

Aged↗
PubMed1991

Urinary desmosine excretion as a marker of lung injury in the adult respiratory distress syndrome.

Desmosine, the intermolecular and intramolecular cross link between the chains of elastin polypeptide, may be useful as a marker of a lung injury in adult respiratory distress syndrome (ARDS). A radioimmunoassay for rabbit antibody developed against desmosine, conjugated to bovine serum albumin, can detect as little as 100 pg of desmosine in plasma or urine. Desmosine is not metabolically absorbed, reused, or catabolized by the body, but rather eliminated unchanged in the urine as low molecular weight peptides. The lung is relatively rich in elastin, and we reasoned that a timed collection could be used as an index of elastin degradation in vivo. A 2-h collection of urine for desmosine assay was obtained at the time of Swan-Ganz catheter insertion in 41 consecutive patients. On the basis of clinical and initial Swan-Ganz catheter data, the patients were assigned to one of three groups: an ARDS group (n = 12); a cardiogenic pulmonary edema (CPE) group (n = 12); and a critically ill, nonpulmonary edema group (NPE, n = 17). The mean urine desmosine concentration (mg/L) for the ARDS group (0.728 +/- 0.22 SE) differed from the CPE group (0.149 +/- 0.07; p less than 0.001). The total excretion (microgram/2 h) was 64.95 +/- 24.7 in the ARDS group and 24.71 +/- 11.7 in the CPE group (p less than 0.05). Urine desmosine concentration/serum creatinine index for the ARDS group (0.78 +/- 0.28) was greater than in the CPE group (0.07 +/- 0.04; p = 0.019). Desmosine excretion was increased in the NPE group compared with CPE and ARDS groups, possibly reflecting heterogeneity in this group. In the differentiation of ARDS from CPE, we conclude that substantial increases in urinary desmosine excretion favor a diagnosis of ARDS.

Adult↗
PubMed1991

Air travel in patients with chronic obstructive pulmonary disease.

Air travel exposes patients with chronic obstructive pulmonary disease to the risk of severe hypoxemia. We sought to determine the frequency and outcome of airline travel in patients with chronic obstructive pulmonary disease. A cohort of 100 patients (76 men and 24 women; age 67 +/- 7 years [mean +/- SD]) with severe chronic pulmonary obstructive disease examined by means of spirometry (forced expiratory volume in the first second, 0.04 +/- 0.35 L), all military retirees, or their dependents, comprised the study population. Forty-four patients traveled by commercial air carrier over a 28-month interval, giving an annual frequency of 18.9% of these patients per year. The group that did not travel by air (n = 56) had a lower mean value for forced expiratory volume in the first second and greater prevalence of home oxygen use than did the group that did travel by air. Twelve of the travelers (27.3%) consulted a physician beforehand. Flights reached foreign destinations for 22.7% of patients. The median duration of the longest flight segment was 3 hours. A minority of patients (34.3%) occupied seats in the smoking sections of aircraft. A majority (56.8%) ambulated aboard the aircraft during flights. Eight patients (18.2%) reported transient symptoms during air travel. We conclude that patients with chronic obstructive pulmonary disease travel with appreciable frequency, often without medical consultation, and develop symptoms in some cases.

Aerospace Medicine↗
PubMed1991

A retrospective analysis of diseases associated with indeterminate HIV western blot patterns.

Some individuals possess antibodies which react to HIV-1 Western blot proteins in patterns not diagnostic for HIV infection. A retrospective chart review of patients exhibiting such indeterminate HIV Western blots was performed in comparison to a control cohort of sex- and age-matched individuals from the same population of HIV-negative blots to determine if such blots were associated with any specific disease states. Twenty such patients with 25 indeterminate blots among them were found in a total population of 816 (2.5%). GAG-only (core) Western blots comprised the majority 84% (21/25). An indeterminate blot was statistically associated with Hashimoto's thyroiditis (p less than 0.01) and non-Hodgkin's lymphoma (p less than 0.05). Kikuchi's disease and malignant histiocytosis were associated but the numbers were too small to reach statistical significance. The possibility that these diseases are caused by novel retroviruses, cross-reactive with HIV-1, is discussed in lieu of these findings.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Accuracy of oxyhemoglobin saturation monitors during simulated altitude exposure of men with chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) are at risk for hypoxemia during air travel. We assessed the comparative performance of oxyhemoglobin saturation (%O2Hb) monitors on these patients during hypobaric exposure. We measured %O2Hb by arterial catheter blood co-oximetry (COOX) and compared these values to those from a transmittance ear oximeter and a reusable digital pulse oximeter. Additionally, we examined the effect of oxygen supplementation (4 L/min) on %O2Hb. A total of 18 ambulatory males with severe COPD were exposed to 8,000 ft (565 mm Hg) in a hypobaric chamber. Multiple measures of %O2Hb were made with each monitor at sea level and at 8,000 ft, with and without supplemental oxygen. By COOX, %O2Hb fell at altitude to clinically significant levels, and was subsequently corrected with supplemental oxygen. Saturations measured by the transmittance ear oximeter were very close to the COOX, underestimating the true value by only 0.6% at altitude (p less than 0.05), while the reusable digital pulse oximeter over-estimated %O2Hb alinearly by a mean of 3.8% at altitude.

Aged↗