Acute kidney injury in critically ill patients with 2009 influenza A (H1N1) viral pneumonia: an observational study

OBJECTIVE

To describe the incidence, risk factors, and impact on mortality of acute kidney injury (AKI) in patients with 2009 influenza A (H1N1) viral pneumonia requiring mechanical ventilation.

DESIGN

Observational cohort study.

PATIENTS AND METHODS

AKI was defined as risk, injury or failure, according to the RIFLE classification. Early and late AKI were defined as AKI occurring on intensive care unit (ICU) day 2 or before, or after ICU day 2, respectively. Demographic data and information on organ dysfunction were collected daily.

RESULTS

Of 84 patients, AKI developed in 43 patients (51%). Twenty (24%) needed renal replacement therapy. Early and late AKI were found in 28 (33%) and 15 (18%) patients, respectively. Patients with AKI, as compared with patients without AKI, had higher Acute Physiology and Chronic Health Evaluation (APACHE) II score and ICU mortality (72% versus 39%, p < 0.01) and presented on admission more marked cardiovascular, respiratory, and hematological dysfunction. Patients with early but not late AKI presented on admission higher APACHE II score and more marked organ dysfunction, as compared with patients without AKI. ICU mortality was higher in late versus early AKI (93% versus 61%, p < 0.001). On multivariate analysis, only APACHE II score and late but not early AKI [odds ratio (OR) 1.1 (95% confidence interval 1.0-1.1) and 15.1 (1.8-130.7), respectively] were associated with mortality.

CONCLUSIONS

AKI is a frequent complication of 2009 influenza A (H1N1) viral pneumonia. AKI developing after 2 days in ICU appears to be associated with different risk factors than early AKI, and is related to a higher mortality rate.

What is the daily practice of mechanical ventilation in pediatric intensive care units? A multicenter study

Objective

To describe the daily practice of mechanical ventilation (MV), and secondarily, its outcome in pediatric intensive care units (PICUs).

Design

Prospective cohort of infants and children who received MV for at least 12 h.

Setting

Thirty-six medical surgical PICUs.

Patients

All consecutive patients admitted to the PICUs during 2-month period.

Measurements and main results

Of the 1893 patients admitted, 659 (35%) received MV for a median time of 4 days (25th percentile, 75%: 2, 6). Median of age was 13 months (25th percentile, 75%: 5, 48). Common indications for MV were acute respiratory failure (ARF) in 72% of the patients, altered mental status in 14% of the patients, and ARF on chronic pulmonary disease in 10% of the patients. Median length of stay in the PICUs was 8 days (25th percentile, 75%: 5, 13). Overall mortality rate in the PICUs was 15% (confidence interval 95%: 13–18) for the entire population, 50% (95% CI: 25–74) in patients who received MV because of acute respiratory distress syndrome, 24% (95% CI: 16–35) in patients who received MV for altered mental status and 16% (95% CI: 9–29) in patients who received MV for ARF on chronic pulmonary disease.

Conclusion

One in every 3 patients admitted to the PICUs requires ventilatory support.. The ARF was the most common reason for MV, and survival of unselected infants and children receiving MV for more than 12 h was 85%.

Electronic Supplementary Material

Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00134-004-2225-5

Evolution in the utilization of the mechanical ventilation in the critical care unit

Use of mechanical ventilation has increased in recent years and constitutes a major therapeutic modality in the intensive care unit (ICU). In the recent years, changes in the ventilatory modes, in the ventilatory strategies and in the weaning from mechanical ventilation have occurred. We have compared the data obtained from the Spanish ICUs in studies that were carried out in three periods of the nineties, with the aim to test whether the aforementioned innovations have modified the clinical practice. We analyzed demographic data, primary reason for mechanical ventilation, ventilatory parameters, mode of weaning and performance of tracheostomy. It was observed a decrease in the percentage of patients receiving mechanical ventilation. There was a significant trend to ventilate older patients over the course of the decade. In the mode of ventilation, we observed a significant decrease in the use of the synchronized intermittent mandatory ventilation with a increment in the use of assist-control ventilation. We did not find differences in the ventilatory settings. Concerning to weaning, over the course of the decade occurred an increase in use of pressure support ventilation and spontaneous breathing trial, being this method the most frequently used at the end of the decade. The performance of the tracheostomy has been lesser and earlier over the time. The results obtained suggest that findings from research on mechanical ventilation are incorporated into clinical practice at a very slow pace whereas the evidence obtained from the clinical trials about weaning has had a better reception.

A randomized and controlled trial of the effect of treatment aimed at maximizing oxygen delivery in patients with severe sepsis or septic shock

OBJECTIVE

To evaluate the effects of increased oxygen delivery on mortality and morbidity.

DESIGN

Randomized, controlled trial.

SETTING

Medical-surgical ICU of a tertiary care hospital.

PATIENTS

Sixty-three patients classified according to predetermined criteria as having severe sepsis or septic shock.

INTERVENTIONS

The patients were randomly assigned to one of two groups: the control group (n = 32) received conventional therapy with a normal targeted value of oxygen delivery, and the treatment group (n = 31) received therapy with a targeted oxygen delivery index (DO2I) value of > 600 mL/min/m2. The therapeutic approach to maintain BP, arterial saturation, hemoglobin concentration, and pulmonary artery occlusion pressure was similar in both groups.

MEASUREMENTS AND MAIN RESULTS

The hemodynamic, oxygen transport, and gastric intramucosal pH measurements were recorded at the time of admission to the study and every 6 h for the next 96 h. The outcome measures were the rate of patient mortality and the number of organ dysfunctions occurring during the ICU stay. The study groups were similar with respect to demographics and admission hemodynamic variables, but the percentage of patients with positive blood cultures was significantly higher in the control group than in the treatment group, respectively: 34 vs 13% (p = 0.04). The average cardiac index was significantly higher in the treatment group than in the control group, respectively: 3.96 vs 3.05 L/min/m2 (p = 0.01). This factor did not significantly affect the DO2I. Nine of the 31 treatment group patients reached an average DO2I value of > 600 mL/min/m2. The rate of mortality in the control group patients up to the time of ICU discharge (66%) was similar to that seen in the treatment group (74%), respectively: 21 of 32 vs 23 of 31 (p = 0.46). The number of dysfunctional organs per patient was also similar in the control and treatment groups, respectively: 2.1+/-1.1 vs 2.6+/-1.2 (p = 0.12).

CONCLUSION

Treatment aimed at maximizing oxygen delivery in patients with severe sepsis or septic shock does not reduce mortality or morbidity.

A comparison of four methods of weaning patients from mechanical ventilation. Spanish Lung Failure Collaborative Group

BACKGROUND

Weaning patients from mechanical ventilation is an important problem in intensive care units. Weaning is usually conducted in an empirical manner, and a standardized approach has not been developed.

METHODS

We carried out a prospective, randomized, multicenter study involving 546 patients who had received mechanical ventilation for a mean (+/- SD) of 7.5 +/- 6.1 days and who were considered by their physicians to be ready for weaning. One hundred thirty patients had respiratory distress during a two-hour trial of spontaneous breathing. These patients were randomly assigned to undergo one of four weaning techniques: intermittent mandatory ventilation, in which the ventilator rate was initially set at a mean (+/- SD) of 10.0 +/- 2.2 breaths per minute and then decreased, if possible, at least twice a day, usually by 2 to 4 breaths per minute (29 patients); pressure-support ventilation, in which pressure support was initially set at 18.0 +/- 6.1 cm of water and then reduced, if possible, by 2 to 4 cm of water at least twice a day (37 patients); intermittent trials of spontaneous breathing, conducted two or more times a day if possible (33 patients); or a once-daily trail of spontaneous breathing (31 patients). Standardized protocols were followed for each technique.

RESULTS

The median duration of weaning was 5 days for intermittent mandatory ventilation (first quartile, 3 days; third quartile, 11 days), 4 days for pressure-support ventilation (2 and 12 days, respectively), 3 days for intermittent (multiple) trials of spontaneous breathing (2 and 6 days, respectively), and 3 days for a once-daily trial of spontaneous breathing (1 and 6 days, respectively). After adjustment for other covariates, the rate of successful weaning was higher with a once-daily trial of spontaneous breathing than with intermittent mandatory ventilation (rate ratio, 2.83; 95 percent confidence interval, 1.36 to 5.89; P < 0.006) or pressure-support ventilation (rate ratio, 2.05; 95 percent confidence interval, 1.04 to 4.04; P < 0.04). There was no significant difference in the rate of success between once-daily trials and multiple trials of spontaneous breathing.

CONCLUSIONS

A once-daily trial of spontaneous breathing led to extubation about three times more quickly than intermittent mandatory ventilation and about twice as quickly as pressure-support ventilation. Multiple daily trials of spontaneous breathing were equally successful.