Darryl Y. Sue

Relation of oxygen uptake to work rate in normal men and men with circulatory disorders

The relation between the increase in oxygen uptake (VO2) and increase in work rate (WR) between unloaded pedaling and maximal work during incremental cycle ergometer exercise was studied in normal men, men with uncomplicated systemic hypertension and ambulatory men with various cardiovascular diseases. The postulation was that impaired peripheral oxygen delivery would reduce the ratio of the oxygen utilized relative to work performed. The ratio of increase in VO2 to increase in WR (delta VO2/delta WR) was relatively constant: 10.29 +/- 1.01 ml/min/W in normal men (n = 54) for exercise 6 to 14 minutes in duration with uniform work increments of 15, 20, 25 or 30 W/min, regardless of age. The value in men with uncomplicated systemic hypertension (n = 24) was not significantly different from that of normal men. However, more than half of the men with peripheral vascular disease (n = 7) or pulmonary vascular disease (n = 5) or men who had electrocardiographic abnormalities during exercise (n = 39) had a significantly lower delta VO2/delta WR, 8.29 +/- 1.17 ml/min/W (p less than 0.05) especially evident as maximal work rates were approached. Thus, delta VO2/delta WR during incremental exercise testing is predictable for normal men and a reduction in this ratio indicates cardiovascular dysfunction.

Diffusing Capacity for Carbon Monoxide as a Predictor of Gas Exchange during Exercise

In patients with pulmonary disease, the diffusing capacity for carbon monoxide has been used to predict abnormal gas exchange in the lung. However, abnormal values for arterial blood gases during exercise are likely to be the most sensitive manifestations of lung disease. We compared the single-breath diffusing capacity for carbon monoxide at rest with measurements of gas exchange during exercise, including arterial oxygen tension, the alveolar-arterial difference in oxygen tension, the arterial-end-tidal difference in carbon dioxide tension, and the dead-space/tidal-volume ratio in 276 current and former shipyard workers. Sixteen workers had a diffusing capacity for carbon monoxide below 70 percent of predicted; one or more measurements of gas exchange during exercise were abnormal in 14. In contrast, of 96 men who had abnormal gas exchange during exercise, only 14 had a diffusing capacity for carbon monoxide below 70 percent of predicted. Neither the type nor the degree of abnormality in gas exchange could be predicted from the diffusing capacity. We conclude that diffusing capacity for carbon monoxide at rest is a specific but insensitive predictor of abnormal gas exchange during exercise and that, if indicated, measurements of arterial blood gases should be obtained during exercise.

Intra-arterial and cuff blood pressure responses during incremental cycle ergometry.

Brachial intra-arterial blood pressure [systolic (AS) and diastolic (AD)] and cuff blood pressure [systolic (CS) and fourth- and fifth-phase diastolic (CD)] were simultaneously measured by a single observer in 13 middle-aged men during 1-min incremental cycle exercise. On the average, the mean AS exceeded the mean CS by 10 to 11 mm Hg, while the mean AD exceeded the average fourth and fifth CD by 5 and 13 mm Hg, respectively. During incremental exercise, AS, CS, AD, and fourth-phase CD increased, while fifth-phase CD decreased. We also measured intra-arterial blood pressure in nine young adult men smokers during 1-min incremental cycle exercise. In both groups, the average intra-arterial blood pressures increased in a relatively linear fashion from rest to maximal exercise: AS change = 74 +/- 5 mm Hg (SE) and AD change = 28 +/- 3 mm Hg for young men; AS change = 59 +/- 5 mm Hg and AD change = 12 +/- 3 mm Hg for middle-aged men. In this population of middle-aged smokers, intra-arterial mean blood pressure during exercise approximated diastolic plus 2/5 pulse pressure for intra-arterial measures or diastolic plus 1/2 pulse pressure for cuff measures rather than the traditional formula of diastolic plus 1/3 pulse pressure.

Capturing the Diagnosis: An Internal Medicine Education Program to Improve Documentation

BACKGROUND Specific and accurate documentation of patient diagnoses and comorbidities in the medical record is critical to drive quality improvement and to ensure accuracy of publicly reported data. Unfortunately, inpatient documentation is taught to internal medicine trainees and practitioners sporadically, if at all. At Harbor-UCLA Medical Center, a public, tertiary care, academic medical center, we implemented an educational program to enhance documentation of diagnoses and comorbidities by internal medicine resident and attending physicians. METHODS The program consisted of a series of lectures and the creation of a pocket card. These were designed to guide providers in accurate documentation of common diagnoses that group to different levels of disease severity, achieved by capturing Centers for Medicare and Medicaid Services complication codes and major complication codes. We started the educational program in January 2010 and used a pre-post design to compare outcomes. The programs impact on complication codes and major complication codes capture rates, mortality index, and case mix index was evaluated using the University Health Consortium database. RESULTS The median quarterly complication codes and major complication codes capture rate for inpatients on the internal medicine service was 42% before the intervention versus 48% after (P = .003). Observed mortality did not change but expected mortality increased, resulting in a 30% decline in median quarterly mortality index (P = .001). The median quarterly case mix index increased from 1.27 to 1.36 (P = .004). CONCLUSIONS Thus, implementation of an internal medicine documentation curriculum improved accuracy in documenting diagnoses and comorbidities, resulting in improved capture of complication codes.

Hepatopulmonary Syndrome in HIV—Hepatitis C Virus Coinfection: A Case Report and Review of the Literature

A wide array of diagnoses must be considered when a patient with advanced liver disease and human immunodeficiency virus (HIV) infection presents with hypoxemia. It is important to entertain the possibility of hepatopulmonary syndrome (HPS) in such patients, a diagnosis that must be confirmed with a contrast-enhanced echocardiogram (bubble study). We describe a case of HPS diagnosed in a patient with HIV infection and chronic liver disease and review the literature on HPS.

Change in Intern Calls at Night After a Work Hour Restriction Process Change

ter hearing ear, this finding should prompt immediate audiometric testing, and urgent otologic referral if a sensorineural loss is confirmed. In light of these data, clinicians should be alert to the possibility of sudden SNHL being overlooked in patients without the expected tuning fork findings. However, among patients presenting with sudden unilateral hearing loss, lateralization of the Weber test to the contralateral ear very reliably predicts a sensorineural etiology, and such patients should be promptly referred and treated accordingly.

A Controlled Investigation of Optimal Internal Medicine Ward Team Structure at a Teaching Hospital

Background The optimal structure of an internal medicine ward team at a teaching hospital is unknown. We hypothesized that increasing the ratio of attendings to housestaff would result in an enhanced perceived educational experience for residents. Methods Harbor-UCLA Medical Center (HUMC) is a tertiary care, public hospital in Los Angeles County. Standard ward teams at HUMC, with a housestaff∶attending ratio of 5∶1, were split by adding one attending and then dividing the teams into two experimental teams containing ratios of 3∶1 and 2∶1. Web-based Likert satisfaction surveys were completed by housestaff and attending physicians on the experimental and control teams at the end of their rotations, and objective healthcare outcomes (e.g., length of stay, hospital readmission, mortality) were compared. Results Nine hundred and ninety patients were admitted to the standard control teams and 184 were admitted to the experimental teams (81 to the one-intern team and 103 to the two-intern team). Patients admitted to the experimental and control teams had similar age and disease severity. Residents and attending physicians consistently indicated that the quality of the educational experience, time spent teaching, time devoted to patient care, and quality of life were superior on the experimental teams. Objective healthcare outcomes did not differ between experimental and control teams. Conclusions Altering internal medicine ward team structure to reduce the ratio of housestaff to attending physicians improved the perceived educational experience without altering objective healthcare outcomes.