Publications

OBJECTIVES

This study was designed to test the hypothesis that active compression-decompression cardiopulmonary resuscitation increases transmitral flow and end-decompression left ventricular volume over levels achieved with standard manual cardiopulmonary resuscitation.

BACKGROUND

Recently, cardiopulmonary resuscitation incorporating active compression and decompression of the chest has been demonstrated to improve hemodynamic status in a canine model and in humans after cardiac arrest.

METHODS

The active compression-decompression device was applied midsternum in five consecutive patients and results compared sequentially (in random order) with those of standard manual cardiopulmonary resuscitation. Both techniques were performed at 80 compressions/min with a 1.5- to 2-in. (3.8 to 5.1 cm) compression depth and a 50% duty cycle. Transesophageal echocardiographic data obtained in each patient included the velocity-time integral of transmitral pulsed Doppler recordings and two-dimensional images of the left ventricle in the long-axis view. Planimetric volume measurements of the left ventricle were obtained at both end-compression and end-decompression.

RESULTS

No difference was observed in end-compression volume between the two techniques (p = 0.81). Increased end-decompression volume (active compression-decompression technique 81.3 +/- 12.5 vs. standard technique 69.4 +/- 10.8, p < 0.05), stroke volume (active compression-decompression technique 32.6 +/- 6.8 vs. standard technique 17.6 +/- 5.2, p < 0.05) and velocity-time integral of transmitral flow (active compression-decompression technique 15.8 +/- 4.3 vs. standard technique 7.8 +/- 2.3, p < 0.05) were found in the active compression-decompression group. The transmitral velocity-time integral was highly correlated with left ventricular stroke volume (r = 0.90).

CONCLUSIONS

Improved transmitral flow, end-decompression left ventricular volume and stroke volume are seen with active compression-decompression resuscitation, suggesting a biphasic cardiothoracic cycle of flow. Active decompression of the chest appears to be a beneficial adjunct to standard cardiopulmonary resuscitation.

OBJECTIVE

To estimate the incidence of work disability among adults with asthma and to evaluate a clinically based illness severity score as a predictor of such disability.

DESIGN

Baseline and follow-up telephone interviews and medical record review.

SETTING

University-based outpatient pulmonary specialty practice.

PATIENTS

Fifty-six patients interviewed at baseline; 42 reinterviewed 2 years later.

MEASUREMENTS

Work disability ascertained by interview report and defined as change in job duties, reduction in pay, or change in job or employment status attributed to asthma. Severity of asthma score derived from medical records and based on respiratory symptom frequency, asthma history, and prescribed medications. Pulmonary function by routine testing. Logistic regression analysis of the 5-year incidence of work disability on severity score and forced expiratory volume in 1 s (FEV1).

RESULTS

The 5-year work disability cumulative incidence was 19 percent for change in duties, 17 percent for reduction in pay, 20 percent for change in job or work status, and 36 percent for any of these measures. The median asthma score was 10 (range, 2 to 26). The mean FEV1 as a percent predicted (FEV1 percent) was 88 +/- 25 percent. Score and FEV1 percent were statistically correlated (r = -0.6, p < 0.0001). Severity of asthma score statistically predicted each measure of work disability (p < 0.01). Addition of FEV1 percent added little additional explanatory power to the logistic regression model (maximum chi 2 = 1.3, p > 0.2).

CONCLUSIONS

Work disability is common among adults with asthma. A severity of asthma score based on clinical variables is statistically correlated with lung function but appears to be a stronger predictor of disability than airflow measured at one point in time.