Impact of tapered-cuff tracheal tube on microaspiration of gastric contents in intubated critically ill patients: a multicenter cluster-randomized cross-over controlled trial

PURPOSE

Studies on the impact of tapered-cuff tracheal tubes on rates of microaspiration and ventilator-associated pneumonia (VAP) in intubated patients have reported conflicting results. The aim of this study was to determine the influence of this shape of tracheal cuff on abundant microaspiration of gastric contents in critically ill patients.

METHODS

All patients intubated in the intensive care unit (ICU) and requiring mechanical ventilation for at least 48 h were eligible for this multicenter cluster-randomized controlled cross-over open-label study. The primary outcome was abundant microaspiration of gastric contents, defined by the presence of pepsin at significant level in >30% of tracheal aspirates. Quantitative measurement of pepsin and salivary amylase was performed in all tracheal aspirates during the 48 h following enrollment.

RESULTS

A total of 326 patients were enrolled in the ten participating ICUs (162 in the PVC tapered-cuff group and 164 in the standard-cuff group). Patient characteristics were similar in the two study groups. The proportion of patients with abundant microaspiration of gastric contents was 53.5% in the tapered-cuff and 51.0% in the standard-cuff group (odds ratio 1.14, 95% CI 0.72-1.82). While abundant microaspiration of oropharyngeal secretions was not significantly different (77.4 vs 68.6%, p = 0.095), the proportion of patients with tracheobronchial colonization was significantly lower (29.6 vs 43.3%, p = 0.01) in the tapered-cuff than in the standard-cuff group. No significant difference between the two groups was found for other secondary outcomes, including ventilator-associated events and VAP.

CONCLUSIONS

This trial showed no significant impact of tapered-cuff tracheal tubes on abundant microaspiration of gastric contents.

TRIAL REGISTRATION

ClinicalTrials.gov, number NCT01948635.

Mathematical coupling of data between global-end diastolic volume index and cardiac index calculated by the PiCCO device: myth or reality?

BACKGROUND

Aim of the study was to investigate whether cardiac index (CI) and global end diastolic volume index (GEDVi) determined from the same thermodilution curve are mathematically coupled during the infusion of an inotropic agent in critically ill patients.

METHODS

Seventeen patients were prospectively studied. CI and GEDVi were evaluated in triplicate by the transpulmonary thermodilution technique with the PiCCO system before and 20 to 30 minutes after increases in dobutamine infusion rate. Mixed linear model was used to determine the within-subject correlation coefficient between changes in CI and GEDVi induced by changes in dobutamine infusion rate.

RESULTS

Dobutamine administration significantly increased CI by 48±35%, whereas the average increase in GEDVi was only 8.2±12.3% but statistically significant (P<0.0001). The increase of GEDVi in response to dobutamine infusion was unexpected given that dobutamine has no recognized effect on right and left ventricular dimensions. Intriguingly, we observed a significant correlation coefficient, in individual patients, between changes in CI and GEDVi (r=0.58, P=0.002).

CONCLUSION

Our study provides evidence that changes in GEDVi are mathematically coupled to changes in CI during dobutamine infusion. Therefore, clinicians using PiCCO device to evaluate GEDVi must be aware of the underlying formula to avoid placing undue reliance on artifactual correlations due to mathematical coupling.

Determinants of noninvasive ventilation success or failure in morbidly obese patients in acute respiratory failure

PURPOSE

Acute respiratory failure (ARF) is a common life-threatening complication in morbidly obese patients with obesity hypoventilation syndrome (OHS). We aimed to identify the determinants of noninvasive ventilation (NIV) success or failure for this indication.

METHODS

We prospectively included 76 consecutive patients with BMI>40 kg/m2 diagnosed with OHS and treated by NIV for ARF in a 15-bed ICU of a tertiary hospital.

RESULTS

NIV failed to reverse ARF in only 13 patients. Factors associated with NIV failure included pneumonia (n = 12/13, 92% vs n = 9/63, 14%; p<0.0001), high SOFA (10 vs 5; p<0.0001) and SAPS2 score (63 vs 39; p<0.0001) at admission. These patients often experienced poor outcome despite early resort to endotracheal intubation (in-hospital mortality, 92.3% vs 17.5%; p<0.001). The only factor significantly associated with successful response to NIV was idiopathic decompensation of OHS (n = 30, 48% vs n = 0, 0%; p = 0.001). In the NIV success group (n = 63), 33 patients (53%) experienced a delayed response to NIV (with persistent hypercapnic acidosis during the first 6 hours).

CONCLUSIONS

Multiple organ failure and pneumonia were the main factors associated with NIV failure and death in morbidly obese patients in hypoxemic ARF. On the opposite, NIV was constantly successful and could be safely pushed further in case of severe hypercapnic acute respiratory decompensation of OHS.

Anaemia to predict outcome in patients with acute coronary syndromes

BACKGROUND

Owing to the heterogeneous population of patients with acute coronary syndromes (ACS), risk stratification with tools such as the GRACE risk score is recommended to guide therapeutic management and improve outcome.

AIM

To evaluate whether anaemia refines the value of the GRACE risk model to predict midterm outcome after an ACS.

METHODS

A prospective registry of 1064 ACS patients (63 ± 14 years; 73% men; 57% ST-segment elevation myocardial infarction [MI]) was studied. Anaemia was defined as haemoglobin less than 13 mg/dL in men or less than 12 mg/dL in women. The primary endpoint was 6-month death or rehospitalization for MI.

RESULTS

The primary endpoint was reached in 132 patients, including 68 deaths. Anaemia was associated with adverse clinical outcomes (hazard ratio 3.008, 95% confidence interval 2.137-4.234; P<0.0001) in univariate analysis and remained independently associated with outcome after adjustment for the Global Registry of Acute Coronary Events (GRACE) risk score (hazard ratio 2.870, 95% confidence interval 1.815-4.538; P<0.0001). Anaemia provided additional prognostic information to the GRACE score as demonstrated by a systematic improvement in global model fit and discrimination (c-statistic increasing from 0.633 [0.571;0.696] to 0.697 [0.638;0.755]). Subsequently, adding anaemia to the GRACE score led to reclassification of 595 patients into different risk categories; 16.5% patients at low risk (≤ 5% risk of death or rehospitalization for MI) were upgraded to intermediate (>5-10%) or high risk (>10%); 79.5% patients at intermediate risk were reclassified as low (55%) or high risk (24%); and 45.5% patients at high risk were downgraded to intermediate risk. Overall, 174 patients were reclassified into a higher risk category (17.3%) and 421 into a lower risk category (41.9%).

CONCLUSION

Anaemia provides independent additional prognostic information to the GRACE score. Combining anaemia with the GRACE score refines its predictive value, which often overestimates the risk.

Use of sodium-chloride difference and corrected anion gap as surrogates of Stewart variables in critically ill patients

Introduction

To investigate whether the difference between sodium and chloride ([Na⁺] – [Cl⁻]) and anion gap corrected for albumin and lactate (AG_corr) could be used as apparent strong ion difference (SID_app) and strong ion gap (SIG) surrogates (respectively) in critically ill patients.

Methods

A total of 341 patients were prospectively observed; 161 were allocated to the modeling group, and 180 to the validation group. Simple regression analysis was used to construct a mathematical model between SID_app and [Na⁺] – [Cl⁻] and between SIG and AG_corr in the modeling group. Area under the receiver operating characteristic (ROC) curve was also measured. The mathematical models were tested in the validation group.

Results

in the modeling group, SID_app and SIG were well predicted by [Na⁺] – [Cl⁻] and AG_corr (R² = 0.973 and 0.96, respectively). Accuracy values of [Na⁺] – [Cl⁻] for the identification of SID_app acidosis (<42.7 mEq/L) and alkalosis (>47.5 mEq/L) were 0.992 (95% confidence interval [CI], 0.963–1) and 0.998 (95%CI, 0.972–1), respectively. The accuracy of AG_corr in revealing SIG acidosis (>8 mEq/L) was 0.974 (95%CI: 0.936–0.993). These results were validated by showing excellent correlations and good agreements between predicted and measured SID_app and between predicted and measured SIG in the validation group (R² = 0.977; bias = 0±1.5 mEq/L and R² = 0.96; bias = −0.2±1.8 mEq/L, respectively).

Conclusions

SID_app and SIG can be substituted by [Na⁺] – [Cl⁻] and by AG_corr respectively in the diagnosis and management of acid-base disorders in critically ill patients.

Impact of functional decline on outcome in elderly patients with acute coronary syndromes

BACKGROUND

Management of acute coronary syndromes in elderly patients is poorly defined.

OBJECTIVE

To assess the impact of functional decline on all-cause mortality in elderly patients with acute coronary syndromes.

METHOD

Clinical data, including the Global Registry of Acute Coronary Events score and assessment of functional status obtained by using the Katz scale, were prospectively collected on 272 patients 70 years or older hospitalized for acute coronary syndromes. All-cause mortality was assessed at 6 months, and longer term outcome data were obtained.

RESULTS

Mean age of the patients was 78 years (SD, 6), and 58% were men. A total of 28% had functional decline. Six months after the index hospitalization, 38 patients had died. Another 29 patients died during a median follow-up of 611 days after the initial 6 months. Functional decline was associated with both 6-month (hazards ratio, 3.63; 95% CI, 1.91-6.88; P < .001) and long-term (hazards ratio, 2.69; 95% CI, 1.28-5.64; P = .009) outcomes. Functional decline remained associated with both 6-month and long-term outcomes in multivariate analysis and was systematically selected in the most predictive multivariate models for 6-month and long-term mortality. The multivariate model including the Global Registry of Acute Coronary Events score and functional decline was predictive of 6-month mortality, but the combination of functional decline and biological data was more predictive of long-term mortality than was a model combining functional decline and the Global Registry score.

CONCLUSIONS

Functional decline in elderly patients with acute coronary syndromes is predictive of poor outcomes.

Extravascular lung water indexed or not to predicted body weight is a predictor of mortality in septic shock patients

PURPOSE

The purpose was to investigate whether extravascular lung water (EVLW) indexed to actual body weight (EVLWa) is an independent predictor of mortality in patients with septic shock, to determine the relationship between EVLWa and other markers of lung injury, and to test if indexing EVLW with predicted body weight (EVLWp) strengthens its predictive power.

METHODS

Extravascular lung water, pulmonary vascular permeability index, and other markers of lung injury were measured prospectively in 55 patients with septic shock for 3 days.

RESULTS

At day 1, EVLWa, EVLWp, and pulmonary vascular permeability index were not significantly different between survivors and nonsurvivors. However, in parallel to the course of septic shock, these variables decreased only in the survivors and remained elevated in the nonsurvivors, reaching intergroup difference by day 3. In multiple logistic regression analysis, both EVLWa and EVLWp (at day 3) were predictors of mortality with an odds ratio of 2 (95% confidence interval, 1.12-3.7) and 1.7 (95% confidence interval, 1.1-2.5) per SD increase, respectively. The receiver operating characteristic curve analysis showed that EVLWp did not improve the discriminative power of EVLW to predict mortality. Extravascular lung water indexed to actual body weight correlated with lung injury score and with the ratio of arterial oxygen partial pressure to inspired oxygen fraction but not with static respiratory compliance. Indexing EVLW to predicted body weight did not ameliorate these correlations.

CONCLUSIONS

Extravascular lung water indexed or not to predicted body weight is an independent predictor of mortality in patients with septic shock. Repeated measurements of EVLW indexes over time, rather than a too-early measurement, seem to be more appropriate for predicting outcome.

Addition of B-type natriuretic peptide to the GRACE score to predict outcome in acute coronary syndrome: a retrospective (development) and prospective (validation) cohort-based study

AIMS

The present study was designed to build and validate a composite score based on the Global Registry of Acute Coronary Events (GRACE) score and B-type natriuretic peptide (BNP) concentrations to predict outcome in patients with acute coronary syndromes (ACS).

METHODS

The GRACE risk score and BNP concentrations were obtained in a retrospective and a prospective cohort. A composite score including the GRACE score and BNP concentrations was first developed in a retrospective cohort of 248 patients with ACS and then validated in a prospective cohort of 575 patients. The primary outcome was 6-month death or myocardial infarction.

RESULTS

End points were reached in 34 patients in the retrospective cohort and in 68 patients in the prospective cohort. Both higher BNP concentration and GRACE score were independently associated with outcome in the retrospective cohort (p=0.003 and p<0.0001). The composite score could be obtained as follows: GRACE+BNP/60. The use of the composite score increased the accuracy of the GRACE score, with an increase in the C statistic from 0.810 (0.727 to 0.892) to 0.822 (0.745 to 0.902) in the retrospective cohort and from 0.724 (0.657 to 0.791) to 0.750 (0.686 to 0.813) in the prospective cohort. Finally, 7% of patients in the prospective study population were reclassified from low to high risk or from high to low risk using this composite score.

CONCLUSIONS

Plasma BNP levels refine the accuracy of the GRACE score. A comprehensive risk score, which includes BNP concentration and the GRACE risk score, might improve ACS risk stratification in clinical practice.