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Biomedical subjects

S K Epstein

Publications and source records attributed to S K Epstein.

34 records · Page 2Linked to original sources
PubMed1998

Independent effects of etiology of failure and time to reintubation on outcome for patients failing extubation.

Patients requiring reintubation after failed extubation have a poor prognosis, with hospital mortality exceeding 30 to 40%, though the reason remains unclear. To examine the impact of etiology of extubation failure and time to reintubation on hospital outcome, we performed a post hoc analysis of prospectively gathered data on 74 MICU patients (47 men, 27 women), 64 +/- 2 yr of age who required reintubation within 72 h of extubation. Cause for reintubation was classified as airway (upper airway obstruction, 11; aspiration/excess pulmonary secretions, 12) or nonairway (respiratory failure, 21; congestive heart failure, 17; encephalopathy, 7; other, 6). The duration of mechanical ventilation prior to extubation was 139 +/- 19 h, and the median time to reintubation was 21 h. Thirty-one of 74 patients (42%) died, with mortality highest for patients failing from nonairway etiologies (27/51, 53% versus 4/23, 17%; p < 0.01). Patients failing from an airway cause tended to be reintubated earlier (21 +/- 4 versus 31 +/- 3 h, p = 0.07). Mortality increased with longer duration of time from extubation to reintubation (<= 12 h, 6/25 versus > 12 h, 25/49; p < 0.05). With multiple logistic regression, both cause for extubation failure and time to reintubation were independently associated with hospital mortality. In conclusion, etiology of extubation failure and time to reintubation are independent predictors of outcome in reintubated MICU patients. The high mortality for those reintubated for nonairway problems indicate that efforts should be preferentially focused on identifying these patients. The effect of time to reintubation suggests that identification of patients early after extubation and timely reinstitution of ventilatory support has the potential to reduce the increased mortality associated with extubation failure.

Aged↗
PubMed1998

Response to symptom-limited exercise in patients with the hepatopulmonary syndrome.

OBJECTIVE: To study the response to symptom-limited exercise in patients with the hepatopulmonary syndrome (HPS). DESIGN: The response to maximal cardiopulmonary exercise (CPX) was studied in 5 patients with HPS and compared with 10 case control (normoxemic, NC) cirrhotics (matched for age, gender, etiology and severity of liver disease, tobacco use, and beta-blocker therapy) and 9 hypoxemic control cirrhotics (HC) without clinical evidence of HPS. SETTING: Cardiopulmonary exercise physiology laboratory in a tertiary care referral center. PATIENTS: Cirrhotics referred for CPX as part of their preliver transplantation evaluation. MEASUREMENTS: Standard pulmonary function tests and echocardiography were performed to assess resting pulmonary and cardiac function. Peak oxygen consumption (VO2), minute ventilation, arterial blood gases, and dead space (VD/VT) were determined during symptom-limited maximal CPX. RESULTS: Resting spirometry and lung volumes were similar between HPS and NC subjects, while HC subjects had restrictive physiology. Differences existed in diffusing capacity corrected for hemoglobin and alveolar volume percent predicted (HPS, 45+/-2 vs NC, 68+/-3, p<0.05; vs HC, 70+/-4, p<0.05), PaO2 (HPS, 70+/-5 mm Hg; HC, 79+/-3 mm Hg, vs NC, 102+/-3 mm Hg, p<0.05) and alveolar-arterial (A-a) O2 gradient (HPS, 42+/-8 mm Hg vs HC, 27+/-2 mm Hg, p<0.05; vs NC, 6+/-2 mm Hg, p<0.05). During CPX, HPS patients achieved a lower peak VO2 percent predicted (HPS, 55+/-6 vs NC, 73+/-3, p<0.05; vs HC, 71+/-5, p<0.05) and VO2 at the ventilatory threshold as percent predicted peak VO2 (HPS, 36+/-2 vs NC, 55+/-4, p<0.05; vs HC 55+/-5, p<0.05). While no differences existed in heart rate and breathing reserve, HPS patients had significantly lower PaO2 (HPS, 50+/-5 mm Hg vs NC, 97+/-4 mm Hg, p<0.05; vs HC, 87+/-6 mm Hg, p<0.05), wider A-a O2 gradient (HPS, 73+/-5 mm Hg vs NC, 13+/-3 mm Hg, p<0.05; vs HC, 31+/-5 mm Hg, p<0.05) and higher VD/VT (HPS, 0.36+/-.03 vs NC, 0.18+/-.02, p<0.05; vs HC, 0.28+/-.02, p<0.05) at peak exercise. For HPS patients, VO2 was negatively correlated with VD/VT (r2=0.9) and positively correlated with PaO2 (r2=0.41) at peak exercise. CONCLUSIONS: Patients with HPS demonstrate a severe reduction in aerobic capacity, beyond that found in cirrhotics without syndrome. The significant hypoxemia and elevated VD/VT at peak exercise suggest that an abnormal pulmonary circulation contributes to further exercise limitation in patients with HPS.

Adult↗
PubMed1997

Effect of failed extubation on the outcome of mechanical ventilation.

OBJECTIVE: To examine medical outcomes associated with reintubation for extubation failure after discontinuation of mechanical ventilation. DESIGN: Prospective cohort study of consecutive intubated medical ICU patients who underwent a trial of extubation at a tertiary-care teaching hospital. The failed extubation group consisted of all patients reintubated within 72 h or within 7 days (if continuous ICU care had been required) of extubation. All others were considered to be successfully extubated. Study end points included hospital death vs survival, the number of days spent in the ICU and in the hospital after the onset of mechanical ventilation, the likelihood of requiring > or = 7 or > or = 14 days of ICU care after extubation, and the need for transfer to either a long-term care or rehabilitation facility among the survivors. RESULTS: Of 289 intubated patients, 247 (85%) were successfully extubated, and 42 (15%) required reintubation for failed extubation (time to reintubation 1.5+/-0.2 days). Reintubation for extubation failure resulted in 12 additional days of mechanical ventilation. When compared with successfully extubated patients, reintubated patients were more likely to die in the hospital (43% vs 12%; p<0.0001), spend more time in the ICU (21.2+/-2.8 days vs 4.5+/-0.6 days; p<0.001) and in the hospital (30.5+/-3.3 days vs 16.3+/-1.2 days; p<0.001) after extubation, and require transfer to a long-term care or rehabilitation facility (38% vs 21%; p<0.05). Using multiple logistic regression, extubation failure was an independent predictor for death and the need for transfer to a long-term care facility. Compared with those successfully extubated, patients who failed extubation were seven times (p<0.0001) more likely to die, 31 times (p<0.0001) more likely to spend > or = 14 days in the ICU after extubation, and six times (p<0.001) more likely to need transfer to a long-term care or rehabilitation facility if they survived. CONCLUSION: After adjusting for severity of illness and comorbid conditions, extubation failure had a significant independent association with increased risk for death, prolonged ICU stay, and transfer to a long-term care or rehabilitation facility. Extubation failure may serve as an additional independent marker of severity of illness. Alternatively, poor outcomes may be etiologically related to extubation failure. If the latter proves to be the case, identifying patients at risk for poor outcomes from extubation failure and instituting alternative care practices may reduce mortality, duration of ICU stay, and need for transfer to a long-term care facility.

Case-Control Studies↗
PubMed1996

Life-threatening "round pneumonia".

Round pneumonia is a rare manifestation of lower respiratory tract infection in adults. Previous reports emphasize that this entity is typically a mild, easily treatable illness that often masquerades radiographically as a neoplasm. We present two cases of round pneumonia, in patients with abnormal immunity, that progressed rapidly to life-threatening septic shock and respiratory failure.

Adult↗
PubMed1996

Influence of gender and endotracheal tube size on preextubation breathing pattern.

An imbalance between work of breathing and respiratory muscle capacity often results in rapid, shallow breathing (increased respiratory rate/tidal volume [f/VT]). Because this imbalance commonly causes unsuccessful weaning from mechanical ventilation, it is not surprising that an elevated f/VT accurately predicts weaning failure. However, while studying extubation outcome, we observed that women and patients with narrow endotracheal tubes are often successfully extubated with an elevated f/VT. We studied 218 medical patients in the intensive care unit who had a f/VT measured through an oral endotracheal tube (off of ventilatory support) during 1 min of spontaneous respiration at the onset of a weaning trial that culminated in extubation. Men and women were comparable at the onset of mechanical ventilation and weaning trials in severity of illness, etiology of respiratory failure, ventilator settings, and gas exchange data. Women were found to have a higher f/VT (79 +/- 5 versus 56 +/- 3 breaths/L, p < 0.001), lower tidal volumes (381 +/- 14 versus 494 +/- 13 ml, p < 0.001), and higher respiratory rate 26 +/- 1 versus 24 +/- 1, p < 0.05). The differences persisted after controlling for extubation outcome. Smaller endotracheal tubes were associated with a higher f/VT, especially for women (< or = 7 mm, 86 +/- 6 versus > 7 mm, 68 +/- 6, p < 0.05). Women were more likely to have a f/VT > or = 100 (19/82 [women] versus 10/136 [men], p < 0.001). Although the overall incidence of extubation failure was similar (11/82 [women] versus 23/136 [men], p = NS), among patients with f/VT > or = 100, men were more likely to require reintubation (3/19 [women] versus 5/10 [men], p = 0.08). We conclude that women, especially when breathing through small endotracheal tubes, have a higher f/VT (including likelihood of f/VT > or = 100) than men, independent of extubation outcome. Consideration of factors that elevate the f/VT, unrelated to physiologic work of breathing and respiratory muscle capacity, should improve application of this index to extubation decision making.

Female↗
PubMed1995

Ventilatory response to arm elevation. Its determinants and use in patients with chronic obstructive pulmonary disease.

During arm elevation, normal individuals predominantly recruit the diaphragm, whereas chronic obstructive pulmonary disease (COPD) patients use more the accessory inspiratory and abdominal expiratory muscles. To test that arm elevation is useful to study the ventilatory muscle response in COPD, and to define the factors that determine this response, we studied 34 patients (FEV1 0.95 +/- 0.08 L) during 2 min of arm elevation. Transnasal balloons were used to determine end-inspiratory and end-expiratory gastric (Pg), pleural (Ppl) and transdiaphragmatic (Pdi) pressures. The slope of delta Pg/delta Ppl (= Pgi - Pge/Ppli - Pple) was used to infer respiratory muscle recruitment. With linear regression, the delta Pg/delta Ppl during arm elevation significantly correlated with resting delta Pg/delta Ppl (r = 0.68), hyperinflation (FRC/TLC, r = 0.52), and diaphragmatic tension time index (TTIdi) (r = 0.47). With multiple regression, resting delta Pg/delta Ppl, percentage predicted FRC (FRC %pred) and TTIdi influenced delta Pg/delta Ppl during arm elevation (r = 0.84). Over the 2 min of arm elevation, the dependency upon resting breathing pattern decreased, while hyperinflation and TTIdi became increasingly important. Higher resting TTIdi values were associated with a faster and shallower breathing pattern (f/VT > or = 38) during arm elevation. We conclude that the pattern of respiratory muscle recruitment during arm elevation depends primarily on the resting breathing pattern. Over 2 min, the degree of hyperinflation and the force reserve of the diaphragm increasingly impact on the ability to recruit the diaphragm. Measurement of f/VT during arm elevation is useful to determine functional reserve of the diaphragm in severe COPD.

Arm↗
PubMed1995

Etiology of extubation failure and the predictive value of the rapid shallow breathing index.

Failure of weaning from mechanical ventilation is thought to result from an imbalance between respiratory muscle capacity and respiratory demand. The ratio of respiratory rate to tidal volume (f/VT, rapid shallow breathing index) during spontaneous unsupported respiration increases when this imbalance exists, and may predict the success or failure of weaning from mechanical ventilation. Using f/VT, Yang and Tobin demonstrated a positive predictive value (PPV) of 0.78 (f/VT < or = 105 and weaning success) (1). To define the etiology of the 20% false-positive rate (FPR, f/VT < or = 105 and weaning failure), 94 patients who had an f/VT determined prior to extubation were studied prospectively. Of 84 patients with an f/VT < 100, 14 required reintubation within 72 h of extubation (FPR = 0.17, PPV = 0.83). Extubation in 13 of these 14 cases failed because of congestive heart failure, upper airway obstruction, aspiration, encephalopathy, or the development of a new pulmonary process. Only one patient needed reintubation solely because of the original respiratory process. Of 10 patients extubated with an f/VT > or = 100, four required reintubation, all because of the underlying respiratory process. This study confirms the high PPV for an f/VT < 100. The FPR of approximately 0.20 is best explained by extubation failure caused by processes for which f/VT is physiologically or temporally unlikely to predict success or failure. The negative predictive value (f/VT > or = 100 but extubation success) for f/VT may be lower than previously reported.

Airway Obstruction↗
PubMed1995

Clinical, echocardiographic, and hemodynamic evidence of cardiac tamponade caused by large pleural effusions.

Large pleural effusions are typically associated with dyspnea and potential respiratory compromise. Experimental evidence suggests that with large effusions, increased intrapleural pressure may be transmitted to the pericardial space, resulting in impaired cardiac filling and reduced stroke volume. We report two cases in which large pleural collections were complicated by hypotension. The effusions were due to an infected right hepatic hydrothorax (Case 1) and a left malignant effusion (Case 2). Echocardiography demonstrated right and left ventricular diastolic collapse, respectively, confirming a diagnosis of cardiac tamponade. Large volume thoracentesis resulted in immediate hemodynamic improvement as demonstrated by a reduction in right ventricular and atrial pressures (Case 1) and echocardiographic resolution of left ventricular diastolic collapse (Case 2). These cases establish that large pleural effusions can cause hemodynamically significant cardiac tamponade. In addition, they illustrate how the demonstration of cardiac compressive physiology can significantly alter the therapeutic approach to large pleural effusions.

Adult↗
PubMed1995

Inability to perform bicycle ergometry predicts increased morbidity and mortality after lung resection.

The ability to successfully exercise has been used to assess the cardiopulmonary risk of thoracotomy for lung cancer. Because of musculoskeletal, neurologic, peripheral vascular, or behavioral problems, not all patients presenting for pulmonary resection are capable of exercising. Using a multifactorial cardiopulmonary risk index (CPRI) consisting of a cardiac risk index (CRI) and a pulmonary risk index, we studied 74 patients (60 capable of exercising and 14 incapable of exercising) who underwent thoracotomy for lung cancer resection. The groups were similar in reference to history of pulmonary disease, preoperative pulmonary function, and pulmonary risk index score. The no-exercise patients were more likely to have a history of cardiac disease (64 vs 28%; p < 0.01) and had a higher CRI score (2.0 +/- 0.2 vs 1.4 +/- 0.1; p < 0.05). Cardiopulmonary postoperative complications (POCs) and mortality were more likely among those in the no-exercise group vs those in the exercise group (POCs, 79 vs 35%, p < 0.01; mortality, 21 vs 2%, p < 0.05). Among the eight no-exercise patients with a CPRI of 4 or more, all eight suffered a POC (100%) and three died (38%). Using multiple logistic regression analysis, both the CPRI score and the inability to exercise were independently associated with increased risk for POCs. We conclude that patients unable to perform even minimal preoperative exercise are at substantially increased risk for morbidity and mortality after lung resection. This results both from greater identifiable preoperative cardiopulmonary risk factors (as assessed by the CPRI) and from an independent effect related to the inability to exercise.

Aged↗
PubMed1994

An overview of respiratory muscle function.

This article reviews the important features of respiratory muscle structure and function, including fiber types, fatigue, work and efficiency of breathing, neural connections, circulation, and mechanical properties. Emphasis is placed on the functional anatomy and the coordination and interaction of respiratory muscle action. Normal function is contrasted with the respiratory muscle dysfunction seen in patients with neuromuscular disease.

Humans↗
PubMed1993

Bronchial stump disruption following inadvertent right mainstem intubation 9 years after pneumonectomy.

An 82-year-old man, with a history of right pneumonectomy 9 years prior to admission, was emergently intubated for respiratory failure resulting from rapid atrial fibrillation and congestive heart failure. Postintubation chest radiograph demonstrated the tube to be in the right bronchial stump. Over the next 48 hours gas exchange remained poor, endotracheal suctioning produced copious serosanguinous secretions, and chest radiographs showed increasing air, with air fluid levels, in the previously opacified right hemithorax. Bronchoscopy demonstrated air bubbling from the posterior wall of the right bronchial stump, consistent with a bronchopleural fistula. The authors conclude that right mainstem intubation, in the setting of a previous right pneumonectomy, can lead to disruption of the bronchial stump with drainage of fluid from the postpneumonectomy space into the functioning left lung with severe compromise of gas exchange.

Aged↗
PubMed1993

Predicting complications after pulmonary resection. Preoperative exercise testing vs a multifactorial cardiopulmonary risk index.

Recent studies have used preoperative cardiopulmonary exercise testing to improve risk assessment of pulmonary resection for lung cancer. These studies have demonstrated inconsistent correlation between peak oxygen uptake (VO2) and postoperative complications but have not systematically examined other methods of risk stratification. We analyzed the findings in 42 patients who had cardiopulmonary exercise testing prior to lung cancer resection. Preoperative clinical data combining pulmonary factors (obesity, productive cough, wheezing, tobacco use, ratio of the forced expiratory volume in 1 s over the forced vital capacity [FEV1/FVC] < 70 percent, and PaCO2 > 45 mm Hg), and an established cardiac risk index were used to generate a cardiopulmonary risk index (CPRI). When analyzed using the risk index, the incidence of postoperative complications increased with higher CPRI scores. Those with a CPRI of 4 or greater were 22 times more likely to develop a complication, compared to a CPRI of less than 4 (p < 0.0001). We found that patients with a peak VO2 less than 500 ml/m2/min (body surface area) were 6 times more likely to experience a cardiopulmonary complication (p < 0.05). With multiple logistic regression analysis, peak VO2 was not an independent predictor of postoperative complications. Analysis also demonstrated that a CPRI of 4 or greater was associated with significant reductions in peak VO2. We conclude that both the peak VO2 during cardiopulmonary exercise testing and a multifactorial CPRI are highly predictive of complications after lung resection. Adding the peak VO2 did not enhance the risk estimation generated by the CPRI. The association between postoperative complications and peak VO2 may be explained by the correlation between identifiable cardiopulmonary disease (CPRI) and reduced oxygen uptake with exercise.

Electrocardiography↗
PubMed1992

Polymicrobial bacterial pericarditis after transbronchial needle aspiration. Case report with an investigation on the risk of bacterial contamination during fiberoptic bronchoscopy.

A 63-yr-old man developed pericardial effusion with tamponade after transbronchial needle aspiration (TBNA) of a subcarinal mass. A diagnosis of polymicrobial bacterial pericarditis was made when pericardiocentesis revealed purulent fluid that grew a mixed culture of anaerobes and aerobes, organisms that constitute part of the normal upper respiratory tract flora. To examine the possibility that contamination of the transbronchial needle (TBN) could lead to purulent pericarditis by inoculation of bacteria into the mediastinum, quantitative cultures of the TBN content were performed in seven consecutive patients. Abundant growth of multiple anaerobic and aerobic organisms was demonstrated in all seven cultures. We conclude that subcarinal TBNA is another potential cause of purulent pericarditis. This results from upper respiratory tract contamination of the open distal end of the TBN as it passes through the suction channel of the bronchoscope.

Bacteria, Aerobic↗
PubMedDate not supplied

Arm training reduces the VO2 and VE cost of unsupported arm exercise and elevation in chronic obstructive pulmonary disease.

BACKGROUND: Patients with severe chronic obstructive pulmonary disease (COPD) may develop dyspnea with minimal arm activity, thoracoabdominal dyssynchrony with unsupported arm exercise (UAEX) and increased oxygen uptake (VO2), and minute ventilation (VE) with simple unsupported arm elevation (UAE) and UAEX. We investigated whether unsupported arm training, as the only form of exercise, could decrease the VO2 and VE cost (percentage increase from resting baseline) associated with unsupported arm elevation and exercise, respectively. METHODS: Twenty-six patients with severe COPD were randomized to 21-24 sessions of unsupported arm (ARMT) or low-intensity resistive breathing (RBT) training as the only form of exercise. Patients were studied before and after training using a metabolic cart and esophageal and gastric pressures to evaluate metabolic and respiratory muscle function. RESULTS: After ARMT, the VO2 (58% vs 38% increase, P < 0.05) and VE (41% v. 21% increase, P < 0.05) cost for UAEX at exercise isotime decreased and endurance time increased. Similarly the VO2 (25% vs 18% increase, P < 0.05) cost decreased and VE no longer increased in response to 2 minutes of UAE after ARMT. The RBT group showed no such change. No improvement in ventilatory load or respiratory muscle function could be identified to explain the physiologic changes observed. After ARMT, mean inspiratory flow (VT/TL), a measure of central respiratory drive, was reduced during UAEX and the expected increase during UAE did not occur. CONCLUSION: We conclude that arm training reduces the VO2 and VE cost of UAE and UAEX, possibly through improved synchronization and coordination of accessory muscle action during unsupported arm activity.

Aged↗
PubMedDate not supplied

Cardiopulmonary exercise testing in patients with chronic obstructive pulmonary disease.

Severe chronic obstructive pulmonary disease is characterized by limited exercise capacity as a result of changes in pulmonary mechanics, abnormal gas exchange, altered cardiac function, respiratory muscle dysfunction, nutritional factors, and dyspnea. Cardiopulmonary exercise testing is a safe, effective method for objectively studying exercise performance and may be carried out using simple walk tests or more complicated treadmill or cycle-ergometry testing. Indications in patients with chronic obstructive pulmonary disease include defining the etiology of dyspnea, evaluating work disability or impairment, and assessing the response to therapy or the need for supplemental oxygen. It is also indicated in preoperative evaluation and as part of a pulmonary rehabilitation program.

Exercise Test↗