Bruno Franco Mazza

Recomendações brasileiras de ventilação mecânica 2013. Parte I

Perspectives on invasive and noninvasive ventilatory support for critically ill patients are evolving, as much evidence indicates that ventilation may have positive effects on patient survival and the quality of the care provided in intensive care units in Brazil. For those reasons, the Brazilian Association of Intensive Care Medicine (Associacao de Medicina Intensiva Brasileira - AMIB) and the Brazilian Thoracic Society (Sociedade Brasileira de Pneumologia e Tisiologia - SBPT), represented by the Mechanical Ventilation Committee and the Commission of Intensive Therapy, respectively, decided to review the literature and draft recommendations for mechanical ventilation with the goal of creating a document for bedside guidance as to the best practices on mechanical ventilation available to their members. The document was based on the available evidence regarding 29 subtopics selected as the most relevant for the subject of interest. The project was developed in several stages, during which the selected topics were distributed among experts recommended by both societies with recent publications on the subject of interest and/or significant teaching and research activity in the field of mechanical ventilation in Brazil. The experts were divided into pairs that were charged with performing a thorough review of the international literature on each topic. All the experts met at the Forum on Mechanical Ventilation, which was held at the headquarters of AMIB in Sao Paulo on August 3 and 4, 2013, to collaboratively draft the final text corresponding to each sub-topic, which was presented to, appraised, discussed and approved in a plenary session that included all 58 participants and aimed to create the final document.

Predictive value of pulse pressure variation for fluid responsiveness in septic patients using lung-protective ventilation strategies

BACKGROUND The applicability of pulse pressure variation (ΔPP) to predict fluid responsiveness using lung-protective ventilation strategies is uncertain in clinical practice. We designed this study to evaluate the accuracy of this parameter in predicting the fluid responsiveness of septic patients ventilated with low tidal volumes (TV) (6 ml kg(-1)). METHODS Forty patients after the resuscitation phase of severe sepsis and septic shock who were mechanically ventilated with 6 ml kg(-1) were included. The ΔPP was obtained automatically at baseline and after a standardized fluid challenge (7 ml kg(-1)). Patients whose cardiac output increased by more than 15% were considered fluid responders. The predictive values of ΔPP and static variables [right atrial pressure (RAP) and pulmonary artery occlusion pressure (PAOP)] were evaluated through a receiver operating characteristic (ROC) curve analysis. RESULTS Thirty-four patients had characteristics consistent with acute lung injury or acute respiratory distress syndrome and were ventilated with high levels of PEEP [median (inter-quartile range) 10.0 (10.0-13.5)]. Nineteen patients were considered fluid responders. The RAP and PAOP significantly increased, and ΔPP significantly decreased after volume expansion. The ΔPP performance [ROC curve area: 0.91 (0.82-1.0)] was better than that of the RAP [ROC curve area: 0.73 (0.59-0.90)] and pulmonary artery occlusion pressure [ROC curve area: 0.58 (0.40-0.76)]. The ROC curve analysis revealed that the best cut-off for ΔPP was 6.5%, with a sensitivity of 0.89, specificity of 0.90, positive predictive value of 0.89, and negative predictive value of 0.90. CONCLUSIONS Automatized ΔPP accurately predicted fluid responsiveness in septic patients ventilated with low TV.

Evaluation of blood transfusion effects on mixed venous oxygen saturation and lactate levels in patients with SIRS/sepsis

PURPOSE To evaluate the effects of red blood cell transfusion in patients with SIRS/sepsis who presented hemoglobin levels under 9.0 g/dL at intensive care unit admission, using two parameters of organ perfusion: mixed venous oxygen saturation and serum lactate levels. METHODS All patients admitted to the intensive care unit with SIRS/sepsis, as defined by Consensus Conference in 1992, and hemoglobin levels under 9.0 g/dL were included. Hemoglobin levels, mixed venous oxygen saturation, and lactate levels were collected before red blood cell transfusion (pre-T) and up to 1 hour after transfusion (post-T). These variables were analyzed through a paired t test, and results were considered significant if P < .05. RESULTS Twenty-nine patients (17 male, 12 female) with ages of 61.9 +/- 15.1 (mean +/- SD) years (range, 21-85 years) and a mean APACHE II score of 12.5 +/- 3.75 (7-21) were transfused with a mean of 1.41 packed red cell units. A significant increase in hemoglobin levels was reached by blood transfusion, from 8.14 +/- 0.64 g/dL (pre-T) to 9.4 +/- 0.33 g/dL (post-T), with P <.001. However, this was not accompanied by a significant change in lactate levels, from 1.87 +/- 1.22 mmol/l (pre-T) to 1.56 +/- 0.28 mmol/l (post-T), with P =.28, or in mixed venous oxygen saturation, from 64.3 +/- 8.52% (pre-T) to 67.4 +/- 6.74% (post-T), with P = .13. The results were similar even in patients with hemoglobin levels under 8.0 g/dL (n = 9). These results suggest that red blood cell transfusions, in spite of leading to a significant increase in hemoglobin levels, are not associated with an improvement in tissue oxygenation in patients with SIRS/sepsis and hemoglobin levels < 9 g/dL.

Improving mortality in sepsis: analysis of clinical trials.

Sepsis accounts for a huge number of deaths in intensive care units worldwide. Encouraging data from recent studies show that some interventions are able to reverse such a picture. Surviving Sepsis Campaign (SSC) bundles were built based on these interventions. Many studies were published analyzing the impact of sepsis protocol implementation on compliance, costs, and mortality, and the results are herein analyzed. Based on these studies, it is not clear if the reduction is secondary to improvement in the quality of care naturally associated with protocol implementation or to the improvement in compliance to strict goals. A high heterogeneity is present among institutions and countries, and the pitfalls for protocol implementation seem to depend on local characteristics. In the same way, the impact of interventions might be different according to each institutions epidemiological profile. Interventions not impacting in low-mortality-rate institutions can be important for places where mortality is high. In Brazil, mortality rates are very high, and the results of Brazilian SSC network are presented and discussed.

The impact of duration of organ dysfunction on the outcome of patients with severe sepsis and septic shock

OBJECTIVES This study aimed to assess the impact of the duration of organ dysfunction on the outcome of patients with severe sepsis or septic shock. METHODS Clinical data were collected from hospital charts of patients with severe sepsis and septic shock admitted to a mixed intensive care unit from November 2003 to February 2004. The duration of organ dysfunction prior to diagnosis was correlated with mortality. Results were considered significant if p<0.05. RESULTS Fifty-six patients were enrolled. Mean age was 55.6 ± 20.7 years, mean APACHE II score was 20.6 ± 6.9, and mean SOFA score was 7.9 ± 3.7. Thirty-six patients (64.3%) had septic shock. The mean duration of organ dysfunction was 1.9 ± 1.9 days. Within the univariate analysis, the variables correlated with hospital mortality were: age (p=0.015), APACHE II (p=0.008), onset outside the intensive care unit (p=0.05), blood glucose control (p=0.05) and duration of organ dysfunction (p=0.0004). In the multivariate analysis, only a duration of organ dysfunction persisting longer than 48 hours correlated with mortality (p=0.004, OR: 8.73 (2.37–32.14)), whereas the APACHE II score remained only a slightly significant factor (p=0.049, OR: 1.11 (1.00–1.23)). Patients who received therapeutic interventions within the first 48 hours after the onset of organ dysfunction exhibited lower mortality (32.1% vs. 82.1%, p=0.0001). CONCLUSIONS These findings suggest that the diagnosis of organ dysfunction is not being made in a timely manner. The time elapsed between the onset of organ dysfunction and initiation of therapeutic intervention can be quite long, and this represents an important determinant of survival in cases of severe sepsis and septic shock.

Accuracy of different methods for blood glucose measurement in critically ill patients

CONTEXT AND OBJECTIVE Although glucometers have not been validated for intensive care units, they are regularly used. The aim of this study was to compare and assess the accuracy and clinical agreement of arterial glucose concentration obtained using colorimetry (Agluc-lab), capillary (Cgluc-strip) and arterial (Agluc-strip) glucose concentration obtained using glucometry and central venous glucose concentration obtained using colorimetry (Vgluc-lab). DESIGN AND SETTING Cross-sectional study in a university hospital. METHOD Forty patients with septic shock and stable individuals without infection were included. The correlations between measurements were assessed both in the full sample and in subgroups using noradrenalin and presenting signs of tissue hypoperfusion. RESULTS Cgluc-strip showed the poorest correlation (r = 0.8289) and agreement (-9.87 +/- 31.76). It exceeded the limits of acceptable variation of the Clinical and Laboratory Standards Institute in 23.7% of the cases, and was higher than Agluc-lab in 90% of the measurements. Agluc-strip showed the best correlation (r = 0.9406), with agreement of -6.75 +/- 19.07 and significant variation in 7.9%. For Vgluc-lab, r = 0.8549, with agreement of -4.20 +/- 28.37 and significant variation in 15.7%. Significant variation was more frequent in patients on noradrenalin (36.4% versus 6.3%; P = 0.03) but not in the subgroup with hypoperfusion. There was discordance regarding clinical management in 25%, 22% and 15% of the cases for Cgluc-strip, Vgluc-lab and Agluc-strip, respectively. CONCLUSION Cgluc-strip should be avoided, particularly if noradrenalin is being used. This method usually overestimates the true glucose levels and gives rise to management errors. CLINICAL TRIAL REGISTRATION ACTRN12608000513314 (registered as an observational, cross-sectional study).

Comparison of lactate values obtained from different sites and their clinical significance in patients with severe sepsis

CONTEXT AND OBJECTIVE The ideal site for lactate collection has not been clearly established. This study aimed to evaluate associations between lactate levels in arterial blood (Lart), peripheral venous blood (Lper) and central venous blood (Lcen) in patients with severe sepsis or septic shock. DESIGN AND SETTING Cross-sectional analytical study in an tertiary university hospital. METHOD Samples from patients with a central venous catheter and from healthy volunteers (control group) were collected. Blood was drawn simultaneously for measurements of Lart, Lper and Lcen, and the first sample was collected less than 24 hours after the onset of organ dysfunction. The results were analyzed using Pearson correlation, Bland-Altman and McNemar tests. RESULTS A total of 238 samples were collected from 32 patients. The correlation results were r = 0.79 (P < 0.0001) for Lart/Lper and r = 0.84 (P < 0.0001) for Lart/Lcen. Bland-Altman showed large limits of agreement: -3.2 ± 4.9 (-12.8 to 6.4) and -0.8 ± 5.9 (-12.5 to 10.8), for Lper and Lcen respectively. In the control group, there was greater correlation (r = 0.9009, P = 0.0004) and agreement: -0.7 ± 1.2 (-3.1 to 1.7). Regarding clinical intervention, there was good agreement between Lart/Lcen (96.3%; three disagreements), with worst results for Lart/Lper (87.0%) with 10 cases of disagreement (P = 0.04). In eight patients (80.0%) Lper was higher than Lart. CONCLUSION Lcen, and not Lper, can replace Lart with good correlation and clinical agreement. Lper tends to overestimate Lart, thus leading to unnecessary therapeutic interventions.

Quality Improvement Initiatives in Sepsis in an Emerging Country: Does the Institution’s Main Source of Income Influence the Results? An Analysis of 21,103 Patients

Objective: We aimed to assess the results of a quality improvement initiative in sepsis in an emerging setting and to analyze it according to the institutions’ main source of income (public or private). Design: Retrospective analysis of the Latin American Sepsis Institute database from 2005 to 2014. Settings: Brazilian public and private institutions. Patients: Patients with sepsis admitted in the participant institutions. Interventions: The quality improvement initiative was based on a multifaceted intervention. The institutions were instructed to collect data on 6-hour bundle compliance and outcomes in patients with sepsis in all hospital settings. Outcomes and compliance was measured for eight periods of 6 months each, starting at the time of the enrollment in the intervention. The primary outcomes were hospital mortality and compliance with 6-hour bundle. Measurements and Main Results: We included 21,103 patients; 9,032 from public institutions and 12,071 from private institutions. Comparing the first period with the eigth period, compliance with the 6-hour bundle increased from 13.5% to 58.2% in the private institutions (p < 0.0001) and from 7.4% to 15.7% in the public institutions (p < 0.0001). Mortality rates significantly decreased throughout the program in private institutions, from 47.6% to 27.2% in the eighth period (adjusted odds ratio, 0.45; 95% CI, 0.32–0.64). However, in the public hospitals, mortality diminished significantly only in the first two periods. Conclusion: This quality improvement initiative in sepsis in an emerging country was associated with a reduction in mortality and with improved compliance with quality indicators. However, this reduction was sustained only in private institutions.

Nurse to Bed Ratio and Nutrition Support in Critically Ill Patients

BACKGROUND Inadequate nutrition support is common among critically ill patients, and identification of risk factors for such inadequacy might help in improving nutrition support. OBJECTIVE To determine how often daily calorie goals are met and the factors responsible for inadequate nutrition support. Methods A single-center prospective cohort study. Each patients demographic and clinical characteristics, the need for ventilatory support, the use and dosage of medications, the number of nursing staff per bed, the time elapsed from admission to the intensive care unit until the effective start of enteral feeding, and the causes for nonadministration were recorded. Achievement of daily calorie goals was determined and correlated with risk factors. RESULTS A total of 262 daily evaluations were done in 40 patients. Daily calorie goal was achieved in only 46.2% of the evaluations (n = 121), with a mean of 74.8% of the prescribed volume of enteral nutrition infused daily. Risk factors for inadequate nutrition support were the use of midazolam (odds ratio, 1.58; 95% CI, 1.18-2.11) and fewer nursing professionals per bed (odds ratio, 2.56; 95% CI, 1.43-4.57). Conclusion Achievement of daily calorie goals was inadequate, and the main factors associated with this failure were the use and dosage of midazolam and the number of nurses available.

Transfusões de sangue no choque séptico: 7,0g/dL é mesmo o limite adequado?

Objective To evaluate the immediate effects of red blood cell transfusion on central venous oxygen saturation and lactate levels in septic shock patients with different transfusion triggers. Methods We included patients with a diagnosis of septic shock within the last 48 hours and hemoglobin levels below 9.0g/dL Patients were randomized for immediate transfusion with hemoglobin concentrations maintained above 9.0g/dL (Group Hb9) or to withhold transfusion unless hemoglobin felt bellow 7.0g/dL (Group Hb7). Hemoglobin, lactate, central venous oxygen saturation levels were determined before and one hour after each transfusion. Results We included 46 patients and 74 transfusions. Patients in Group Hb7 had a significant reduction in median lactate from 2.44 (2.00 - 3.22) mMol/L to 2.21 (1.80 - 2.79) mMol/L, p = 0.005, which was not observed in Group Hb9 [1.90 (1.80 - 2.65) mMol/L to 2.00 (1.70 - 2.41) mMol/L, p = 0.23]. Central venous oxygen saturation levels increased in Group Hb7 [68.0 (64.0 - 72.0)% to 72.0 (69.0 - 75.0)%, p < 0.0001] but not in Group Hb9 [72.0 (69.0 - 74.0)% to 72.0 (71.0 - 73.0)%, p = 0.98]. Patients with elevated lactate or central venous oxygen saturation < 70% at baseline had a significant increase in these variables, regardless of baseline hemoglobin levels. Patients with normal values did not show a decrease in either group. Conclusion Red blood cell transfusion increased central venous oxygen saturation and decreased lactate levels in patients with hypoperfusion regardless of their baseline hemoglobin levels. Transfusion did not appear to impair these variables in patients without hypoperfusion. ClinicalTrials.gov NCT01611753Objective: To evaluate the immediate effects of red blood cell transfusion on central venous oxygen saturation and lactate levels in septic shock patients with different transfusion triggers. Methods: We included patients with a diagnosis of septic shock within the last 48 hours and hemoglobin levels below 9.0g/dL Patients were randomized for immediate transfusion with hemoglobin concentrations maintained above 9.0g/dL (Group Hb9) or to withhold transfusion unless hemoglobin felt bellow 7.0g/dL (Group Hb7). Hemoglobin, lactate, central venous oxygen saturation levels were determined before and one hour after each transfusion. Results: We included 46 patients and 74 transfusions. Patients in Group Hb7 had a significant reduction in median lactate from 2.44 (2.00 - 3.22) mMol/L to 2.21 (1.80 - 2.79) mMol/L, p = 0.005, which was not observed in Group Hb9 [1.90 (1.80 - 2.65) mMol/L to 2.00 (1.70 - 2.41) mMol/L, p = 0.23]. Central venous oxygen saturation levels increased in Group Hb7 [68.0 (64.0 - 72.0)% to 72.0 (69.0 - 75.0)%, p < 0.0001] but not in Group Hb9 [72.0 (69.0 - 74.0)% to 72.0 (71.0 - 73.0)%, p = 0.98]. Patients with elevated lactate or central venous oxygen saturation < 70% at baseline had a significant increase in these variables, regardless of baseline hemoglobin levels. Patients with normal values did not show a decrease in either group. Conclusion: Red blood cell transfusion increased central venous oxygen saturation and decreased lactate levels in patients with hypoperfusion regardless of their baseline hemoglobin levels. Transfusion did not appear to impair these variables in patients without hypoperfusion. ClinicalTrials.gov NCT01611753