Improved outcome based on fluid management in critically ill patients requiring pulmonary artery catheterization.

We performed a randomized, prospective trial to evaluate whether fluid management that emphasized diuresis and fluid restriction in patients with pulmonary edema could affect the development or resolution of extravascular lung water (EVLW), as well as time on mechanical ventilation and time in the intensive care unit (ICU), in critically ill patients requiring pulmonary artery catheterization (PAC). PAC was performed on 101 patients. A total of 52 patients were randomized to an EVLW management group using a protocol based on bedside indicator-dilution measurements of EVLW. The other 49 patients were randomized to a wedge pressure (WP) management group in whom fluid management decisions were guided by WP measurements. A total of 89 patients had pulmonary edema (defined as EVLW greater than 7 ml/kg ideal body weight). Except for a clinically unimportant difference in mean age, the two groups were entirely comparable at baseline. The study groups were managed differently, as evidenced by cumulative input-output of 2,239 +/- 3,695 ml (median = 1,600 ml) in the WP group versus 142 +/- 3,632 ml (median = 754 ml) in the EVLW group (p = 0.001). EVLW decreased significantly, and ventilator-days and ICU days were significantly shorter only in patients from the EVLW group. No clinically significant adverse effect occurred as a result of following the EVLW group algorithm. Thus, a lower positive fluid balance, especially in patients with pulmonary edema regardless of cause, is associated with reduced EVLW, ventilator-days, and ICU days.

Effect of smoking on pulmonary vascular permeability. A positron emission tomography study.

Positron emission tomography (PET) can be used to evaluate pulmonary vascular endothelial permeability by measuring the pulmonary transcapillary escape rate (PTCER) for radiolabeled transferrin. Because epithelial permeability, as evaluated by other techniques, is significantly affected by cigarette smoking, we used PET to compare the effects of smoking on extravascular lung density (EVD) and PTCER in seven normal chronic cigarette smokers within 30 min of smoking a cigarette and seven normal nonsmokers. We found no difference in PTCER and EVD between the two groups. We conclude that the interpretation of acute or chronic lung injury studies with PET should not be affected by cigarette smoking in the subject population.

Fluid balance during pulmonary edema. Is fluid gain a marker or a cause of poor outcome?

STUDY OBJECTIVE: To evaluate the importance of fluid balance and changes in extravascular lung water (EVLW) on survival in the ICU and short-term outcome in patients with pulmonary edema. DESIGN: Retrospective analysis of data (sorting by survival and "treatment received") from a recent randomized controlled trial of fluid restriction in this population. SETTING: Medical ICU of a university-affiliated, tertiary-care medical center. PATIENTS: Eighty-nine patients (from the previously mentioned study) requiring pulmonary artery catheterization with abnormally high EVLW (greater than 7 ml/kg). MEASUREMENTS AND RESULTS: When analyzed by survival, the survivors had no significant fluid gain or change in EVLW but decreased wedge pressure and body weight, compared to nonsurvivors. When analyzed by fluid balance, patients who gained less than 1 L of fluid by 36 hours into the study had a better rate of survival (74 percent) than the rest (50 percent; p less than 0.05). Also, the median duration of days on the ventilator, ICU days, and days of hospitalization was approximately half as long for each variable in the group with less than 1 L of fluid gain. Even accounting for baseline differences in the severity of illness, fluid balance was an independent predictor of survival (p less than 0.05). When analyzed by whether or not EVLW decreased by more than 15 percent between the first and last measurement, only patients with ARDS or sepsis had decreased days on the ventilator and ICU days. CONCLUSIONS: These data support the concept that positive fluid balance per se is at least partially responsible for poor outcome in patients with pulmonary edema and defend the strategy of attempting to achieve a negative fluid balance if tolerated hemodynamically.

A positron emission tomographic comparison of pulmonary vascular permeability during the adult respiratory distress syndrome and pneumonia.

We measured extravascular density (EVD) and the pulmonary transcapillary escape rate (PTCER) for 68Ga-transferrin using positron emission tomography in 14 normal volunteers and 29 patients with radiographic infiltrates, including six patients with congestive heart failure (CHF), eight patients with the adult respiratory distress syndrome (ARDS), and 15 patients with focal pneumonia. Contralateral, radiographically normal regions were also evaluated in the patients with focal pneumonia. Mean EVD was elevated in the patients with CHF, ARDS, and pneumonia in regions of radiographic infiltrate compared with values from normal subjects (p less than 0.05), but it was not significantly different among the three patient groups. PTCER in normal subjects and in patients with CHF was not significantly different (21 +/- 11 versus 44 +/- 16 x 10(-4) min-1, respectively, p = NS). PTCER was elevated in regions of infiltrate because of either pneumonia (173 +/- 99) or ARDS (170 +/- 79). PTCER was also elevated in regions contralateral to those with focal infiltrate during pneumonia, even though these regions were radiographically normal and had normal EVD values. These results suggest that PTCER is a sensitive but nonspecific index of abnormal pulmonary vascular permeability, which may be useful for classifying patients in clinical studies of pulmonary edema.

Single versus double indicator dilution measurements of extravascular lung water.

OBJECTIVE: To compare a simplified method of measuring extravascular lung water (EVLW) using only a single indicator (EVLW-SI) with the standard double indicator dilution technique (EVLW-DI). DESIGN: Direct comparison of EVLW-SI with EVLW-DI in 18 critically ill patients. SETTING: A general medical ICU in a university-affiliated hospital. PATIENTS: Nine men and nine women, ages 19 to 80 yr. Six patients were in shock (four from septic shock), and 11 were in respiratory failure. INTERVENTIONS: EVLW-DI and cardiac output were measured in triplicate during injection of cold indocyanine green dye. Cardiac output was calculated both from pulmonary artery (COpa) and femoral artery (COfem-di) thermal dilution signals. EVLW-SI and COfem-si were also measured during three additional injections of cold saline using only thermal signals from the pulmonary and femoral arteries. Order of measurements was random. EVLW-SI was measured in ten patients while blood was withdrawn through the femoral catheter and in ten patients without blood drawn through the femoral catheter. MEASUREMENTS AND MAIN RESULTS: A total of 84 comparisons were made. Although the overall correlations were good (r2 = .86), EVLW-SI systematically overestimated EVLW-DI (p less than .05). This difference was greater when EVLW-SI was measured without blood withdrawal through the femoral catheter. In this subgroup, mean values for EVLW by the two methods were within 20% of one another in only two of ten patients, in contrast to the results in six of eight patients in which blood was withdrawn through the catheter. COfem-si and COfem-di also overestimated COpa. CONCLUSIONS: Theoretically, neither injection of green dye nor blood withdrawal should be necessary during measurements of EVLW-SI, making it a simpler technique for bedside use than EVLW-DI. However, significant discrepancies exist between the two techniques. Some of this difference is apparently due to technical factors related to catheter design. In any case, we cannot recommend use of the single indicator dilution technique at present to estimate EVLW.

Pulmonary vascular permeability during the adult respiratory distress syndrome: a positron emission tomographic study.

The natural history of change in pulmonary vascular permeability (PVP) during the adult respiratory distress syndrome (ARDS) is unknown. Therefore, we evaluated PVP by measuring the pulmonary transcapillary escape rate (PTCER) for transferrin with positron emission tomography (PET) in 15 ARDS patients, including 5 patients studied within 4 days of onset and 13 patients studied at least 7 days after onset. In 3 patients, studies were performed at both early and late stages. These results were compared to 12 non-smoking adult volunteers. Regional PTCER and extravascular lung density (EVD) were determined from a 1-h PET scan after intravenous injection of gallium-68 citrate, which binds rapidly to native transferrin. Oxygenation, radiologic score, as well as outcome were recorded for each patient. Mean PTCER was highest during the early phase of ARDS (560 +/- 275 x 10(-4) min-1) although PTCER in the late ARDS patients was also significantly higher than in normals (319 +/- 187 vs 58 +/- 33 x 10(-4) min-1; p less than .01). EVD was similar in both early and late ARDS groups (.39 +/- .08 and .37 +/- .13 g/ml lung, respectively) and markedly higher than in normals (.22 +/- .05 g/ml lung, p less than 0.01). PTCER decreased in each of the 3 serial studies. The correlation between PTCER and EVD was poor, as were correlations for either PTCER or EVD versus changes in oxygenation, radiologic score, survival, or duration of ventilator dependency. In the late ARDS patients, PTCER was usually elevated even if EVD had returned to normal.(ABSTRACT TRUNCATED AT 250 WORDS)