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Biomedical subjects

S K Epstein

Publications and source records attributed to S K Epstein.

At least 19 recordsLinked to original sources
PubMed2002

Decision to extubate.

The need for reintubation within 24-72 h of planned extubation is a common event, occurring in 2-25% of extubated patients. Risk factors for extubation failure include being a medical, multidisciplinary or paediatric patient; age >70 years; a longer duration of mechanical ventilation; use of continuous intravenous sedation; and anaemia (haemoglobin <10 g/dl or haematocrit <30%) at the time of extubation. The pathophysiology of extubation failure can be distinct from that seen with weaning failure and includes upper airway obstruction, inadequate cough, excess respiratory secretions, encephalopathy, and cardiac dysfunction. Extubation failure prolongs the duration of mechanical ventilation, increases the length of ICU and hospital stay, increases the need for tracheostomy, and is associated with a higher hospital mortality. Great emphasis has been placed on accurately predicting extubation outcome because extubation delay is also associated with increased length of stay and mortality. Tests designed to assess for upper airway obstruction, secretion volume, and the effectiveness of cough seem most promising for improving the decision to extubate. Mortality increases with delays in reintubation for patients failing extubation. Timely identification of patients at elevated risk of extubation failure followed by rapid re-establishment of ventilatory support can improve outcome.

Airway Obstruction↗
PubMed2001

Weaning from prolonged mechanical ventilation.

The development of weaning failure and need for PMV is multifactorial in origin, involving disorders of pulmonary mechanics and complications associated with critical illness. The underlying disease process is clearly important when discussing mechanisms of ventilator dependence; interventions therefore must be tailored to individual patients. Unfortunately, the main conclusion that can be drawn from the sum of the studies investigating patients on PMV to date is that an evidence-based approach to weaning is not possible and more research needs to be done. New studies need to incorporate severity-of-illness scores and an assessment of principal and comorbid conditions to allow for comparison of the findings from different centers. The best approach to a patient requiring PMV after exclusion of easily treatable conditions is not known. The literature regarding both acute and chronic cases suggests that a systematic approach to weaning involving the participation of multiple caregivers, including nurses, physicians, and respiratory, physical, and speech therapists facilitates liberation from MV. Although a gradual decrement in ventilator support would seem prudent, Scheinhorn et al have begun to identify a subpopulation of patients who can tolerate an acceleration of the weaning process. Given the known complications associated with MV, it is crucial that further research be performed to identify patients as soon as they are capable of breathing spontaneously. The literature demonstrates through multiple studies that satisfactory patient outcomes are attainable and can be achieved at LTAC facilities in a more cost-effective manner than in an ICU setting. The trend toward the concentration of patients into specialized regional weaning centers should facilitate the research process and continue to improve outcomes in this population.

Critical Care↗
PubMed2001

Predictors of outcome for patients with COPD requiring invasive mechanical ventilation.

INTRODUCTION: Accurate outcomes data and predictors of outcomes are fundamental to the effective care of patients with COPD and in guiding them and their families through end-of-life decisions. DESIGN: We conducted a retrospective cohort study of 166 patients using prospectively gathered data in patients with COPD who required mechanical ventilation for acute respiratory failure of diverse etiologies. RESULTS: The in-hospital mortality rate for the entire cohort was 28% but fell to 12% for patients with a COPD exacerbation and without a comorbid illness. Univariate analysis showed a higher mortality rate among those patients who required > 72 h of mechanical ventilation (37% vs 16%; p < 0.01), those without previous episodes of mechanical ventilation (33% vs 11%; p < 0.01), and those with a failed extubation attempt (36% vs 7%; p = 0.0001). With multiple logistical regression, higher acute physiology score measured 6 h after the onset of mechanical ventilation, presence of malignancy, presence of APACHE (acute physiology and chronic health evaluation) II-associated comorbidity, and the need for mechanical ventilation > or = 72 h were independent predictors of poor outcome. CONCLUSIONS: We conclude that among variables available within the first 6 h of mechanical ventilation, the presence of comorbidity and a measure of the severity of the acute illness are predictors of in-hospital mortality among patients with COPD and acute respiratory failure. The occurrence of extubation failure or the need for mechanical ventilation beyond 72 h also portends a worse prognosis.

APACHE↗
PubMed2001

Respiratory acidosis.

Respiratory acidosis, or primary hypercapnia, is the acid-base disorder that results from an increase in arterial partial pressure of carbon dioxide. Acute respiratory acidosis occurs with acute (Type II) respiratory failure, which can result from any sudden respiratory parenchymal (eg, pulmonary edema), airways (eg, chronic obstructive pulmonary disease or asthma), pleural, chest wall, neuromuscular (eg, spinal cord injury), or central nervous system event (eg, drug overdose). Chronic respiratory acidosis can result from numerous processes and is typified by a sustained increase in arterial partial pressure of carbon dioxide, resulting in renal adaptation, and a more marked increase in plasma bicarbonate. Mechanisms of respiratory acidosis include increased carbon dioxide production, alveolar hypoventilation, abnormal respiratory drive, abnormalities of the chest wall and respiratory muscles, and increased dead space. Although the symptoms, signs, and physiologic consequences of respiratory acidosis are numerous, the principal effects are on the central nervous and cardiovascular systems. Treatment for respiratory acidosis may include invasive or noninvasive ventilatory support and specific medical therapies directed at the underlying pathophysiology.

Acidosis, Respiratory↗
PubMed2000

Weaning parameters.

Numerous weaning parameters have been studied over the past three decades. These tests range from easily performed maneuvers such as determining the breathing pattern to complex measurements requiring special equipment such as the mechanical work of breathing. Based on the available evidence, it seems that a negative weaning parameter may not be sufficient justification for delaying weaning trials. Clinicians wishing to use weaning parameters must be aware of the testing methodology and should consider adjusting the thresholds used based on individual patients' characteristics, including the estimated risks of each additional day of mechanical ventilation and the perceived risk of a failed trial of weaning. In a patient repeatedly failing weaning trials, parameters may help elucidate the mechanism for failure thereby providing a target for therapeutic intervention, leading to successful liberation.

Decision Support Techniques↗
PubMed2000

Endotracheal extubation.

Over the last decade, investigators have increasingly focused on the process of translaryngeal extubation. Depending on the patient population studied, the frequency of extubation failure varies from 2% to 20%. The pathophysiology of extubation failure is distinct from that of weaning failure. Patients failing extubation have a high mortality, significant prolongation of mechanical ventilation, and longer duration of hospital stay. Commonly used weaning predictors are much less accurate in foretelling extubation outcome. Rapid reinstitution of either invasive or noninvasive ventilatory support has the potential to improve the outcome of extubation failure.

Decision Making↗
PubMed2000

Effect of unplanned extubation on outcome of mechanical ventilation.

Unplanned extubation is a major complication of translaryngeal intubation, but its impact on mortality, duration of mechanical ventilation (MV), length of intensive care unit (ICU) and hospital stay, and need for ongoing hospital care has not been adequately defined. We performed a case-control study in a tertiary-care medical ICU, comparing 75 patients with unplanned extubation and 150 controls matched for Acute Physiology and Chronic Health Evaluation II score, presence of comorbid conditions, age, indication for MV, and sex. Forty-two (56%) patients required reintubation after unplanned extubation (74% immediately, 86% within 12 h). Thirty-three (44%) unplanned extubations occurred during weaning trials, and 30% of these patients needed reintubation (failed unplanned extubation). In contrast, 76% of patients with unplanned extubation occurring during ventilatory support required reintubation. Although mortality was similar to that of controls (failed unplanned extubation 40%, versus control 31%, p > 0.2), patients with failed unplanned extubation had a significantly longer duration of MV (19 versus 11 d, p < 0.01), longer stay in the ICU (21 versus 14 d, p < 0.05), and longer hospital stay (30 versus 21 d, p < 0.01), and survivors were more likely to require chronic care (64% versus 24%, p < 0.001). Successfully tolerated unplanned extubation was associated with a reduction in time from beginning of weaning to extubation (0.9 versus 2.0 d, p = 0.06), but with no difference in overall duration of MV, mortality, discharge location, ICU, or hospital stay as compared with these measures for controls. We conclude that unplanned extubation is not associated with increased mortality when compared with that of matched controls, although it does result in prolonged MV, longer ICU and hospital stay, and increased need for chronic care. These effects are due exclusively to patients who fail to tolerate unplanned extubation. Although successfully tolerated unplanned extubation decreased the duration of weaning trials, it had no other measurable beneficial impact on outcome.

Adult↗
PubMed1999

Overdose of Rogaine Extra Strength for Men topical minoxidil preparation.

CASE REPORT: Minoxidil is a potent arterial vasodilator used in the treatment of hypertension. A side effect, hypertrichosis, has prompted the marketing of a topical preparation, Rogaine, for the treatment of male-pattern baldness. Recently, a 5% solution of minoxidil became available over-the-counter as Rogaine Extra Strength For Men Hair Regrowth Treatment. We describe an oral overdose of minoxidil 3 g as the Rogaine Extra Strength preparation. Toxicity manifested as profound hypotension, requiring vasopressor support, intubation, prolonged tachycardia, and fluid overload with pleural effusions, requiring several days of therapy with furosemide. This is the largest reported ingestion of minoxidil and the first reported overdose of the extra strength 5% solution.

Administration, Oral↗
PubMed1999

Lack of influence of gender on outcomes of mechanically ventilated medical ICU patients.

STUDY OBJECTIVES: Recent studies combining medical and surgical patients have suggested that mortality is higher for mechanically ventilated women than for men. This study was designed to determine whether there are gender-based differences in outcomes in mechanically ventilated medical ICU (MICU) patients. DESIGN AND SETTING: Prospective observational study in an MICU of a tertiary-care academic medical center. PATIENTS: Five hundred eighty consecutive patients admitted to the MICU service and mechanically ventilated for a minimum of 12 h. RESULTS: There was no difference in overall hospital mortality rate (woman, 36.3%; men, 40.4%; p > 0.2). No differences in mortality rates were noted after stratification based on age, underlying comorbid condition, APACHE (acute physiology and chronic health evaluation) II score, indication for mechanical ventilation, or acute hepatic or renal failure. Using a multiple logistic regression model, gender was not independently associated with hospital mortality. No differences were found between men and women for a number of secondary outcomes, including likelihood of undergoing weaning trials, success of weaning trials, time between onset of mechanical ventilation and extubation, total time on mechanical ventilation, rate of unplanned extubations, need for reintubation or tracheostomy, or duration of MICU and hospital stay, after the onset of mechanical ventilation. The number and timing of orders written to withhold care were comparable between men and women. CONCLUSIONS: Using univariate and multivariate analyses, we found no differences in hospital mortality rates between mechanically ventilated men and women. Differences in the process of care or gender-based treatment bias may explain previously reported differences in outcomes.

APACHE↗
PubMed1998

Analysis of impaired exercise capacity in patients with cirrhosis.

Exercise limitation in cirrhosis is typically attributed to a cirrhotic myopathy (without impaired oxygen utilization) and/or a cardiac chronotropic dysfunction. We performed symptom-limited cardiopulmonary exercise testing in 19 cirrhotics without confounding variables (cardiopulmonary disease, beta blockade, anemia, smoking). Twelve concurrently exercised patients without cirrhosis and with normal resting pulmonary function were controls. Oxygen consumption (VO2) at peak exercise, at anaerobic threshold (VO2-AT), work rate (WR), and heart rate (HR) were measured. Cirrhotics had significantly lower peak WR (73+/-4 vs 107+/-7% predicted, p < 0.001), VO2 (72+/-4 vs 98+/-5% predicted, P < 0.001), VO2-AT (53+/-4 vs 71+/-5% predicted peak VO2, P < 0.01), HR (83+/-2 vs 91+/-2% predicted, P < 0.01) and were more likely to have chronotropic dysfunction (peak HR < 85% predicted). Six cirrhotics had normal aerobic capacity (peak VO2 > 80% predicted), while 13 were abnormal. The abnormals had an earlier AT (46+/-2 vs 67+/-3% predicted peak VO2, P < 0.05) but no difference in peak HR percent predicted was found. In conclusion, two thirds of cirrhotics, without confounding factors, have significantly reduced aerobic capacity. Cirrhotic myopathy (without impaired O2 utilization) and cardiac chronotropic dysfunction do not adequately account for the observed decrease in aerobic capacity.

Adult↗
PubMed1998

Acute lung injury in the medical ICU: comorbid conditions, age, etiology, and hospital outcome.

The independent effects of chronic disease, age, severity of illness, lung injury score (LIS) and etiology, and preceding nonpulmonary organ-system dysfunction (OSD) on the outcome of acute lung injury (ALI) have not been examined in an exclusively medical-intensive-care-unit (MICU) population. Therefore, 107 consecutive MICU patients with ALI (76% with acute respiratory distress syndrome [ARDS]) were prospectively investigated. The impact of comorbidities, age > 65 yr, acute physiology score (APS), LIS, etiology of ALI, and OSD on hospital survival were studied. The overall mortality was 62 of 107 patients (58%), including 47 (58%) with ARDS. With univariate analysis, age > 65 yr, organ transplantation, human immunodeficiency virus (HIV) infection, active malignancy, chronic steroid use, and a septic or aspiration-related etiology of ALI were associated with a > or = 1.2-fold greater relative risk (RR) of hospital mortality. With multiple logistic regression, independent predictors of hospital death were age > 65 yr, organ transplantation, HIV infection, cirrhosis, active malignancy, and sepsis. APS, LIS, aspiration-related etiology of ALI, preceding OSD, and other comorbidities were not independently predictive of hospital death. Multivariate analysis of the ARDS cohort showed similar results, although cirrhosis and malignancy did not reach statistical significance. We conclude that comorbid conditions, older age, and sepsis etiology are independent predictors of hospital death in exclusively MICU patients with ALI (76% of whom satisfied criteria for ARDS). These factors should be considered in analyzing studies of new therapies and interpreting trends in mortality for ALI and ARDS.

Adult↗
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↗