Fever in trauma patients: evaluation of risk factors, including traumatic brain injury

BACKGROUND

The role of fever in trauma patients remains unclear. Fever occurs as a response to release of cytokines and prostaglandins by white blood cells. Many factors, including trauma, can trigger release of these factors.

OBJECTIVES

To determine whether (1) fever in the first 48 hours is related to a favorable outcome in trauma patients and (2) fever is more common in patients with head trauma.

METHOD

Retrospective study of trauma patients admitted to the intensive care unit for at least 2 days. Data were analyzed by using multivariate analysis.

RESULTS

Of 162 patients studied, 40% had fever during the first 48 hours. Febrile patients had higher mortality rates than did afebrile patients. When adjusted for severity of injuries, fever did not correlate with mortality. Neither the incidence of fever in the first 48 hours after admission to the intensive care unit nor the number of days febrile in the unit differed between patients with and patients without head trauma (traumatic brain injury). About 70% of febrile patients did not have a source found for their fever. Febrile patients without an identified source of infection had lower peak white blood cell counts, lower maximum body temperature, and higher minimum platelet counts than did febrile patients who had an infectious source identified. The most common infection was pneumonia.

CONCLUSIONS

No relationship was found between the presence of fever during the first 48 hours and mortality. Patients with traumatic brain injury did not have a higher incidence of fever than did patients without traumatic brain injury. About 30% of febrile patients had an identifiable source of infection. Further studies are needed to understand the origin and role of fever in trauma patients.

Comparing outcomes of HIV versus non-HIV patients requiring mechanical ventilation

BACKGROUND

Mechanical ventilation (MV) is a predictor of mortality in patients infected with human immunodeficiency virus (HIV) in the intensive care unit (ICU). Patients with HIV-infections are admitted to the ICU for a variety of reasons that frequently require intubation. While survival rates for HIV-infected patients continue to improve, ICU admission rates have remained consistent.

METHODS

To observe the consequences of MV in HIV-infected patients, we conducted a retrospective chart review on patients with HIV (n=55) vs. matched HIV-negative patients (n=55) who required MV over a one-year period and compared the groups for differences in outcome and complications.

RESULTS

The HIV group had twice the number of deaths (44% vs. 22%, all-cause mortality) (P=0.01). Among the HIV-positive group, 5 of 55 patients required tracheostomy and prolonged MV, compared to 15 of 55 in the control group (9% and 27%, respectively). Successful extubation was virtually identical (47% MV vs. 50% control). Ventilator-associated pneumonia (VAP) was significantly higher among HIV-positive cases (39 of 55 HIV vs. 14 of 55 non-HIV) (P=0.05). Regression analysis revealed that hypotension, hypoalbuminemia, and fever predicted a poorer outcome. Low CD4 cell counts were strongly associated with mortality.

CONCLUSION

HIV-infected patients requiring MV have significantly higher mortality and VAP rates than HIV-negative patients. Since VAP is associated with a poor prognosis, discovering ways to prevent it in the HIV-infected patient may improve outcome.

Recurrent negative pressure pulmonary edema

An African-American man, aged 34 years, underwent an elective uncomplicated right wrist laceration repair while under general anesthesia. Following extubation, the patient developed hypoxemia, tachypnea, shortness of breath, pulmonary rales, frothy sputum, decreased oxygen saturation, and evidence of upper airway obstruction. Chest radiograph showed pulmonary edema. The patient was diagnosed with post-extubation pulmonary edema (aka. negative pressure pulmonary edema [NPPE]) and was treated with intravenous furosemide and oxygen therapy; he improved remarkably within a few hours. Once stabilized, the patient described a similar episode 10 years earlier following surgery for multiple gunshot wounds. Negative pressure pulmonary edema following tracheal extubation is an uncommon (0.1%) and life-threatening complication of patients undergoing endotracheal intubation and general anesthesia for surgical procedures. The common pattern in these cases is the occurrence of an episode of airway obstruction upon emergence from general anesthesia, usually caused by laryngospasm. Patients who are predisposed to airway obstruction may have an increased risk of airway complications upon extubation after general anesthesia. Prevention and early relief of upper airway obstruction should decrease incidence. Recurrent NPPE has not been previously described in the literature. Herein, we describe the first case of recurrent NPPE in the same patient following extubation.

Comparison of levalbuterol and racemic albuterol in hospitalized patients with acute asthma or COPD: a 2-week, multicenter, randomized, open-label study

BACKGROUND

The National Heart, Lung, and Blood Institute guideline recommends that dosing racemic albuterol be administered every 1 to 4 hours for treating patients with asthma or chronic obstructive pulmonary disease (COPD) in the hospital. Previously published preliminary and retrospective studies suggested that levalbuterol can be administered every 8 hours for the treatment of bronchoconstriction in hospitalized patients. However, it is unclear how the different dosing regimens affect the total number of nebulizations (scheduled plus as-needed treatments) and the costs of treatment of bronchoconstriction in a hospital setting. Moreover, it is not clear how the different dosing regimens affect symptom outcomes and health status in hospitalized patients with asthma or COPD.

OBJECTIVE

The aim of this study was to evaluate these issues in hospitalized patients with acute asthma or COPD.

METHODS

In this prospective, multicenter, randomized, open-label study, hospitalized patients aged > or = 18 years were randomly assigned to receive 14-day treatment with levalbuterol 1.25 mg q6-8h or racemic albuterol 2.5 mg q1-4h, administered per routine hospital practice at each institution. The primary efficacy end point was total number of nebulizations during hospitalization. Pulmonary function, symptom evaluation (subject general well-being score [SGWB], disease symptom assessment [DSA], and beta-mediated adverse effect scores), hospital costs (excluding medication costs) and hospital length of stay (LOS) were also evaluated.

RESULTS

In the intent-to-treat population (n = 479; levalbuterol, 241;racemic albuterol, 238), the mean (SE) age was 55.3 (16.9) years, the majority of patients were white (57.8%), and the mean (SE) weight was 80.9 (24.5) kg. Demographic characteristics were similar between the 2 treatment groups, except that there were more females with COPD in the levalbuterol treatment group (63.88%) compared with the racemic albuterol treatment group (45.5%) (P = 0.005). Patients treated with levalbuterol required significantly fewer median total nebulizations (10 vs 12; P = 0.031) and scheduled nebulizations (9 vs 11; P = 0.009) compared with those in the racemic albuterol group. The 2 treatment groups required 0 rescue nebulizations. Mean (SD) forced expiratory volume in 1 second improved from baseline with both levalbuterol and racemic albuterol (0.06 [0.43] and 0.10 [0.37] L, respectively); these improvements were maintained throughout the hospital stay (0.11 [0.48] and 0.16 [0.52] L). DSA and SGWB scores improved significantly from baseline in both treatment groups, and beta-mediated adverse effects mean scores were significantly greater with levalbuterol versus racemic albuterol (P < 0.001). In the levalbuterol and racemic albuterol treatment groups, hospital LOS (70.6 and 65.7 hours, respectively), time to discharge (66.0 and 62.8 hours), and total hospital costs (least squares mean [SE], US $4869.30 [$343.58] and $4899.41 [$343.20]) were similar.

CONCLUSIONS

In these hospitalized patients with acute asthma or COPD treated with levalbuterol every 6 to 8 hours or racemic albuterol every 1 to 4 hours, significantly fewer total nebulizations were required with levalbuterol, without an increased need for rescue nebulizations during 14 days of hospitalization. Both treatments were associated with improvements from baseline in symptoms and health status. The costs of treating bronchoconstriction in hospitalized patients were similar between the levalbuterol and racemic albuterol groups.

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.

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.

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.

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.

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.