Prolonged Mechanical Ventilation as a Predictor of Mortality After Cardiac Surgery.

BACKGROUND: Mortality among the small percentage of cardiac surgery patients receiving prolonged mechanical ventilation is high, but this issue appears to be inadequately addressed in guidelines. METHODS: This study is a retrospective analysis of prospective, multi-center, and observational study in Spain including all adults undergoing cardiac surgery in 3 Andalusian hospitals between June 2008 and December 2012. RESULTS: The study included 3,588 adults with mean ± SD age of 63.5 ± 12.8 y and with median (interquartile range) EuroSCORE of 5 (3-7) points. Prolonged mechanical ventilation (> 24 h) was required by 415 subjects (11.6%), with ICU mortality of 44.3% (184 subjects), and was not required by 3,173 subjects (88.4%), with ICU mortality of 3.1% (99 subjects, P < .001). Prolonged mechanical ventilation was associated with more complications and was required by 4.5% of subjects with a EuroSCORE <5, 11.2% with a score of 5-7, 27.2% with a score of 8-10, and 32.2% with a score > 10. In the multivariable analysis, ICU mortality was associated with illness severity, duration of bypass surgery, surgery type, and prolonged mechanical ventilation (odds ratio 15.19, 95% CI 11.56-22.09). The main cause of death was multiple organ failure and sepsis in subjects who required prolonged mechanical ventilation (50.3%) and cardiogenic shock in those who did not (59.2%). CONCLUSION: Prolonged postoperative mechanical ventilation was required by 10-20% of cardiac surgery subjects, who constitute a specific group that represents most of the postoperative mortality, which is associated with multiple organ failure and sepsis.

Discrepancies in the RIFLE classification are due to the method used to assess the level of derangement of kidney function.

PURPOSE: We hypothesized that RIFLE based on creatinine clearance (CrCl) is superior to that based on serum creatinine (sCr) or Cockroft-Gault (C-G) because it is an earlier marker of kidney dysfunction. MATERIALS AND METHODS: At day 3 of admission, we compared the RIFLE based on sCr, C-G, and CrCl with 28-day mortality and development of RIFLE-F during intensive care unit stay. RESULTS: Percentages in the RIFLE levels were similar for the 3 estimates, but the patients included in each level were different; with CrCl as the reference, κ statistic was 0.29 (95% confidence interval, 0.15-0.43) for sCr and 0.21 (0.07-0.36) for C-G. Mortality at day 28 was 19.3%, with percentages of mortality increasing with RIFLE based in CrCl but not sCr or C-G (area under the curve, 0.57 [45-72] for C-G; 0.57 [44-72] for sCr; and 0.64 [52-79] for CrCl). Logistic regression only showed an independent relationship with mortality for RIFLE measured with CrCl. CONCLUSIONS: RIFLE classification using sCr or C-G at the third day of admission predicts outcome less accurately than with the use of CrCl. Because of the delay in the rise of sCr after a sudden glomerular filtration rate decrease, RIFLE based in CrCl may represent an advantage in terms of precocity.

Replacement of 24-h creatinine clearance by 2-h creatinine clearance in intensive care unit patients: a single-center study.

OBJECTIVE: To estimate the usefulness of 2-h creatinine clearance (CrCl) in the ICU and define variables that may reduce agreement. DESIGN: Prospective study. SETTING: Polyvalent ICU of a university hospital. PATIENTS: 359 patients. INTERVENTIONS: We compared 24-h CrCl (CrCl-24h), as the standard measure, with 2-h CrCl (CrCl-2h) (at the start of the period) and the Cockroft-Gault equation (Ck-G). MEASUREMENTS AND RESULTS: The 2-h sample was lost in two patients (0.6%) and the 24-h sample was lost in 50 patients (13.9%). The mean Ck-G was 87.4+/-3.05, with CrCl-2h 109.2+/-4.46 and CrCl-24h 100.9+/-4.21 ml/min/1.73 m2 (r2 of 0.88 for CrCl-2h and 0.84 for Ck-G). The differences from ClCr-24h were 21.8+/-3.3 (p<0.001) for the Ck-G and 8.3+/-2.6 (p<0.05) for CrCl-2h (p<0.05). In the subgroup of patients with CrCl-24h<100 ml/min/1.73 m2, the CrCl-24h value was 52.9+/-2.71 vs. 51.6+/-2.14 for CrCl-2h (p=ns) and 57.6+/-2.56 (p<0.001) for the Ck-G. Patients with CrCl<100 ml/min only showed variability in hyperglycemia during the 24-h period. CONCLUSIONS: In intensive care patients, 24-h CrCl results in a large proportion of non-valid determinations, even under conditions of close monitoring. Two-hour CrCl is an adequate substitute, even in patients who are unstable or who have irregular diuresis where a 24-h collection is impossible. The Cockroft-Gault equation seems less useful in this setting.

Early hemodynamic improvement is a prognostic marker in patients treated with continuous CVVHDF for acute renal failure.

We examined whether hemodynamic improvement after high-flow hemofiltration predicts survival in patients treated with standard continuous renal replacement therapy (CRRT). This was a prospective, observational cohort study of 169 patients, measuring the mean arterial pressure (MAP) and norepinephrine (NE) dosage before and 24 hours after CRRT. Responders were defined as having a 20% reduction in NE dosage or a 20% rise in MAP with no increase in NE, compared with nonresponders. Patients were considered to be unstable if they were receiving NE or their MAP was lower than 60 mm Hg before CRRT. Of the 169 patients, 68% were men; mean age was 53.8 years (52.7 to 54.9), with a mean Acute Physiology and Chronic Health Evaluation (APACHE) II at admission of 21.8 (21.2 to 22.3), of whom 114 were unstable at the start of CRRT. Overall mortality rate 15 days after the end of CRRT was 54.3% (57.7% in stable vs. 52.9% in unstable patients, p = NS). There were 99 responders and 70 nonresponders, the only differences being NE dosage (higher in responders, p < 0.01) and mortality rate (responders 30% vs. nonresponders 74.7%, p < 0.001). In unstable patients, mortality rate was 30% in responders versus 87% in nonresponders (p < 0.001) (72% sensitivity and 86% specificity for predicting death). Logistic regression analysis showed that the only variables associated with death were APACHE II at admission (OR, 1.06; 95% CI, 1.0 to 1.12), percent creatinine decrease (OR, 0.98; CI, 0.96 to 1.0), and lack of hemodynamic response to CRRT (OR, 7.04; CI, 3.3 to 15.02). Hemodynamic improvement after 24-hour CRRT is a strong predictor of survival.