Tracheobronchomalacia: dynamic airway evaluation with multidetector CT.

OBJECTIVE. The objective of our study was to evaluate the role of dynamic inspiratory-expiratory imaging with multidetector CT in patients with suspected tracheobronchomalacia. CONCLUSION. Multidetector CT with inspiratory-expiratory imaging is a promising method in the evaluation of patients with dynamic airway collapse. In our study, the degree of dynamic collapse correlated well with bronchoscopic results. Dynamic expiratory multidetector CT may offer a feasible alternative to bronchoscopy in patients with suspected tracheobronchomalacia.

Do-not-resuscitate practices in the chronically critically ill.

OBJECTIVES: To determine the frequency of do-not-resuscitate (DNR) orders in the chronically critically ill; to identify the differences in clinical and demographic characteristics of chronically critically ill patients who have DNR orders and those who do not; to identify the differences in the cost of care between patients with and without DNR orders; and to identify the differences in DNR practices between an experimental special care unit and the traditional intensive care unit (ICU). DESIGN: Randomized, prospective design with a block randomization scheme. SUBJECTS: Two hundred twenty patients who met the following eligibility criteria for enrollment in a parent study of the special care unit: an ICU stay of at least 5 days, an absence of pulmonary artery monitoring, an absence of frequent titration of intravenous vasopressors, an Acute Physiology and Chronic Health Evaluation II score of less than 18, and a Therapeutic Intervention Scoring System score of less than 39. SETTING: A large, urban academic medical center. MEASURES: Clinical and demographic variables describing the study populations, mental status, and timing of DNR orders, mortality rates, and cost of hospitalization. RESULTS: There was no difference in the frequency of DNR orders between the special care unit versus the intensive care unit--although patients in the special care unit had a longer interval between hospital admission and initiation of the DNR order. DNR patients differed from non-DNR in that they were older, less likely to be married, and had a higher Acute Physiology and Chronic Health Evaluation II score on admission to the study. The mortality rate in the DNR group was 71% versus 6% in the non-DNR group. There was no difference in total costs. DNR patients were also more likely to have an impaired mental status on admission, and more likely to have deterioration in mental status by the time of discharge than the non-DNR patients.

Intentional drug overdose: predictors of clinical course in the intensive care unit.

OBJECTIVE: To examine the characteristics of patients admitted to the Medical Intensive Care Unit (MICU) after intentional drug overdose. DESIGN: Retrospective chart review, descriptive. SETTING: Midwestern teaching hospital. SUBJECTS: Convenience sample of 43 patients admitted to the MICU after intentional drug overdose. OUTCOME MEASURES: Survival and disposition of those patients who survived and were discharged from the MICU. RESULTS: Ninety-five percent of the patients survived and were discharged from the MICU; Acute Physiology and Chronic Health Evaluation II scores ranged from 1 to 29 (mean, 8); Glascow Coma Scale scores ranged from 3 to 15 (mean 12.5); five patients were intubated and two patients had serious electrocardiograph changes requiring pharmacologic intervention for dysrhythmia. CONCLUSIONS: Neurologic findings were the best indicators of serious complications after drug overdose. THerefore, patients with a Glascow Coma Scale score of more than six, and who are not intubated, may not need admission to an intensive care unit.

Survival experience of chronically critically ill patients.

Intensive care unit (ICU) patients were randomly assigned to either a traditional ICU or a special care unit (SCU) for chronically critically ill patients. The SCU used a low-technology, family-oriented environment, nursing case management, no physician house staff, and a shared governance model. In comparison, the ICU used high technology, limited family visiting, primary care nursing, and a bureaucratic management model. The survival experience of chronically critically ill patients in the two environments during hospitalization, as well as after hospital discharge, was examined. Using survival analytic techniques, the 1-year cumulative mortality for all patients in the study was found to be 59.9%. Risk of death was significantly lower after discharge than during hospitalization. Similar mortality experiences were found for SCU and ICU patients. Thus, the high-technology ICU environment did not produce better outcomes than the SCU environment.

Patient outcomes for the chronically critically ill: special care unit versus intensive care unit.

The purpose of this study was to compare the effects of a low-technology environment of care and a nurse case management case delivery system (special care unit, SCU) with the traditional high-technology environment (ICU) and primary nursing care delivery system on the patient outcomes of length of stay, mortality, readmission, complications, satisfaction, and cost. A sample of 220 chronically critically ill patients were randomly assigned to either the SCU (n = 145) or the ICU (n = 75). Few significant differences were found between the two groups in length of stay, mortality, or complications. However, the findings showed significant cost savings in the SCU group in the charges accrued during the study period and in the charges and costs to produce a survivor. The average total cost of delivering care was $5,000 less per patient in the SCU than in the traditional ICU. In addition, the cost to produce a survivor was $19,000 less in the SCU. Results from this 4-year clinical trial demonstrate that nurse case managers in a SCU setting can produce patient outcomes equal to or better than those in the traditional ICU care environment for long-term critically ill patients.

Weaning chronically critically ill adults from mechanical ventilatory support: a descriptive study.

BACKGROUND: Ventilator-dependent patients average 11,419 daily in US acute care hospitals. OBJECTIVE: To describe the process of ventilatory weaning among chronically critically ill adults. METHODS A retrospective survey was used to study ventilator-dependent adults enrolled in a larger randomized study. Patients records were used to obtain duration of mechanical ventilatory support, success of weaning, serum albumin level, left ventricular function, number of drugs used to treat heart failure, and 24-hour fluid balance. Data were collected on admission to the intensive care unit; 24 hours after initiation of mechanical ventilation; and 7 days before, and on the day of, weaning status determination. RESULTS: Of 174 subjects, 120 were weaned from mechanical ventilation. There were no differences in maximum inspiratory pressure, minute ventilation, or ventilatory capacity between successful and unsuccessful candidates. There were differences in serum albumin level, rapid shallow breathing index, fraction of inspired oxygen, and 24-hour fluid balance. Among subjects who were weaned, the duration of mechanical ventilation was significantly longer in those with left ventricular dysfunction (n = 53; 29.1 +/- 25.2 days) than in those with normal left ventricular function (n = 67; 21.1 +/- 18.1 days). Subjects who were weaned received a greater number of drugs to treat heart failure (1.46 +/- 1.24) than did those who were not (0.77 +/- 1.04). CONCLUSIONS Many weaning parameters do not differentiate patients able to be weaned from those who are unable. The presence of left ventricular dysfunction, number of drugs used to treat heart failure, serum albumin level, and 24-hour fluid balance were associated with weaning success and/or duration of mechanical ventilation in adults requiring prolonged mechanical ventilation.

Withdrawal of mechanical ventilation: ethical principles and guidelines for terminal weaning.

BACKGROUND: Discontinuation of mechanical ventilation because of the recognition of futility of continued treatment or because of patient or family request is an increasingly frequent occurrence in critical care. Although there is broad consensus about the patient's right to refuse life support, little has been written about the actual procedure of withdrawing mechanical ventilation. OBJECTIVE: The purposes of this article are: (1) to review ethical arguments supporting the view that it may be morally permissible to withdraw mechanical ventilation from patients who are neither terminally ill nor imminently dying and (2) to provide guidelines for the procedure of ventilator withdrawal. METHOD: Ethical principles supporting the position that ventilator withdrawal under these conditions can be morally justified and principles suggesting that ventilator withdrawal is morally objectionable are evaluated. Factors contributing to clinicians' ambivalence about this issue and guidelines for planning and implementing treatment withdrawal are discussed.

Hemodynamic status in critically ill patients with and without acute heart disease.

Physicians have been urged to reduce the use of the pulmonary artery catheter. However, there are no guidelines to help the clinician make the decision to use or withhold invasive monitoring in the individual patient. This study was designed to examine the accuracy of physician estimates of cardiac function in a spectrum of patients with hemodynamic instability to determine whether differences in accuracy among subgroups would suggest subgroups of patients who could be managed without invasive measurements. Physician estimates of cardiac index were found to be sufficiently accurate in patients without acute heart disease that initial management without invasive monitoring may be appropriate in selected cases. However, due to the general inaccuracy of physician estimates, efforts to improve the accuracy of clinical judgments of cardiac function and hemodynamic status should be pursued with vigor in patients both with and without acute cardiac dysfunction.

Pulmonary blastoma with malignant melanoma component.

Pulmonary blastomas are rare primary tumors that consist of tubular or glandular structures embedded in an undifferentiated mesenchymal stroma. Focal cartilage, bone, and skeletal muscle as well as squamous differentiation have been described in these tumors. We report a unique case of a pulmonary blastoma showing a malignant melanoma component. Immunohistochemical stains for S100 protein and HMB-45 were positive in the areas of melanocytic differentiation.

Helium-oxygen breathing in severe chronic obstructive pulmonary disease.

The effect of breathing helium-oxygen (He-O2) mixtures was evaluated in 15 patients with severe chronic obstructive pulmonary disease (COPD). Gas exchange was assessed during quiet breathing at rest before and after 15 minutes of breathing 80 percent He-20 percent O2 mixtures in all patients. Functional residual capacity (FRC) determined during argon (Ar) washing studies fell significantly while breathing He-O2, but we did not find significant changes in minute ventilation, tidal volume, respiratory frequency, or inspiratory or expiratory timing. Eleven patients showed decreases in arterial PCO2 and CO2 excretion during resting breathing on He-O2. Expiratory flows were increased at a given lung volume during He-O2 breathing as expected. Apparently, mechanical work of breathing was decreased in patients with severe COPD while breathing He-O2, leading to a reduction in VCO2 and improvement in overall alveolar ventilation. These findings lend support to the therapeutic use of He-O2 under some conditions in patients with severe COPD.

Inspiratory flow effects on mechanically ventilated patients: lung volume, inhomogeneity, and arterial oxygenation.

Changes in the inspiratory flow rate of mechanically ventilated patients can affect arterial oxygenation. Although the mechanism producing this alteration is not certain, one possible mechanism is a change in ventilation inhomogeneity. This study was performed to determine if the inspiratory flow setting would affect ventilation inhomogeneity in patients who have minimal or no lung disease, but who require mechanical ventilation after cardiopulmonary bypass surgery. When inspiratory flows were doubled, PaO2 increased and FRC fell. However, no associated change in ventilation inhomogeneity was detected. It is concluded that inspiratory flow rate can affect arterial oxygenation of subjects without severe obstructive pulmonary disease through mechanisms other than altering ventilation inhomogeneity, such as changes in cardiac output or in distribution of perfusion.

Dysfunction of small airways following pulmonary injury due to nitrogen dioxide.

Serial physiologic studies were performed to characterize both the immediate and delayed effects of a single occupational exposure to nitrogen dioxide in a nonsmoker. During the initial acute stage of pulmonary edema, the abnormal static pressure-volume curve and decreased static compliance corresponded to a reduction in pulmonary volume. During the delayed acute stage, elastic recoil and properties of resistance to flow were normal, but dynamic compliance was reduced and dependent on respiratory frequency, and oxygen transport was abnormal during exercise, which is consistent with dysfunction of the small airways.

Bronchodilating effect of terbutaline aerosol.

We compared the efficacy of terbutaline with that of metaproterenol, isoproterenol, and placebo aerosols in 16 asthmatic patients. Terbutaline, metaproterenol, and isoproterenol produced equivalent improvements in flow rates. At 5 hr, the effect of terbutaline on tests of small airways, FEF25%--75%, and FEF50%, was greater (p less than 0.05) than that of metaproterenol and isoproterenol. Terbutaline produced no significant change of heart rate or blood pressure.

Cardiac arrhythmias during routine tests of pulmonary function in patients with chronic obstruction of airways.

We studied the frequency of cardiac arrhythmias during routine tests of pulmonary function by using continuous electrocardiographic recording and a computerized method to quantitate arrhythmias. A total of 150 patients with chronic obstruction of airways were studied before, during, and after routine tests of pulmonary function performed before and after intermittent positive-pressure breathing (IPPB) with a bronchodilator aerosol. The only significant (P less than 0.01) change was an increased frequency of atrial premature beats during tests of pulmonary function. Spirometric studies, maximal voluntary ventilation, and IPPB with a bronchodilator aerosol were equally likely to induce atrial premature beats. Routine tests of pulmonary function represent an additional causal factor in producing arrhythmias in patients with obstruction of airways, although no clinical consequences were evident in the course of the study.