Impact of positive end-expiratory pressure on the definition of acute respiratory distress syndrome

Objective We examined whether PEEP during the first hours of ARDS can induce such a change in oxygenation that could mask fulfillment of the AECC criteria of a PaO₂/FIO₂ 200 essential for ARDS diagnosis.Design and setting Observational, prospective cohort in two medical-surgical ICU in teaching hospitals.Patients 48 consecutive patients who met AECC criteria of ARDS on 0 PEEP (ZEEP) at the moment of diagnosis.Measurements and results PaO₂/FIO₂ and lung mechanics were recorded on admission (0 h) to the ICU on ZEEP, and after 6, 12, and 24 h on PEEP levels selected by attending physicians. Lung Injury Score (LIS) was calculated at 0 and 24 h. PaO₂/FIO₂ rose significantly from 121±45 on ZEEP at 0 h, to 234±85 on PEEP of 12.8±3.7 cmH₂O after 24 h. LIS did not change significantly (2.34±0.53 vs. 2.42±0.62). These variables behaved similarly in pulmonary and extrapulmonary ARDS, and in survivors and nonsurvivors. After 24 h only 18 patients (38%) still had a PaO₂/FIO₂ of 200 or lower. Their mortality was similar to that in the remaining patients (61% vs. 53%).Conclusions The use of PEEP improved oxygenation such that one-half of patients after 6 h, and most after 24 h did not fulfill AECC hypoxemia criteria of ARDS. However, LIS remained stable in the overall series. These results suggest that PEEP level should be taken into consideration for ARDS diagnosis.     

Extravascular lung water to blood volume ratios as measures of pulmonary capillary permeability in nonseptic critically ill patients

Purpose

The aim of this study is to evaluate the value of extravascular lung water (EVLW) to intrathoracic blood volume, global end-diastolic volume, or pulmonary blood volume ratios as a reflection of pulmonary permeability in nonseptic critically ill patients with or at risk for acute lung injury/acute respiratory distress syndrome (ALI/ARDS).

Methods

Pulmonary permeability was measured by the pulmonary leak index (PLI) for ⁶⁷gallium-labeled transferrin and EVLW and blood volumes by the transpulmonary indicator dilution technique in 20 mechanically ventilated patients, before and after fluid loading, guided by changes in central venous pressure.

Results

Nine (45%) patients had ALI/ARDS according to current criteria. The PLI was high (≥30.0 × 10⁻³/min) in 25% before and 30% after fluid loading. The EVLW was high (≥10 mL/kg) in 10% before and in none after fluid loading and did not increase with fluid loading, whereas blood volumes increased. Before fluid loading, PLI related to EVLW/blood volume ratios (minimum r = 0.48, P = .032). After fluid loading, PLI related to EVLW to pulmonary blood volume or intrathoracic blood volume ratios (minimum r = 0.46, P = .041). The relations were unaffected by fluid loading and pressure forces.

Conclusions

The EVLW/blood volume ratios are determined, at least in part, by moderately increased pulmonary permeability in nonseptic critically ill patients with or at risk for ALI/ARDS, independent of fluid status and pressure forces. Normal ratios may help to exclude high permeability.     

Intraoperative adherence to a low tidal volume ventilation strategy in critically ill patients with preexisting acute lung injury

Purpose

Low tidal volume (LTV) ventilation reduces mortality in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). This study investigates adherence of intraoperative LTV and whether patient outcomes were different with or without continued intraoperative LTV ventilation in patients with previously established ALI or ARDS.

Materials and Methods

A retrospective analysis was performed of adults with ALI/ARDS over a 2-year period who underwent surgery between 24 hours and 14 days after the diagnosis of ALI/ARDS. The main outcome was intraoperative LTV use. Secondary outcomes included perioperative respiratory and clinical outcomes.

Results

Of the 249 patients who underwent surgery between 24 hours and 14 days after ALI/ARDS diagnosis, 101 (41%) received preoperative LTV ventilation. Fifty-four (53%) received intraoperative LTV ventilation, whereas 47 (47%) did not. Use of preoperative LTV ventilation was associated with use of intraoperative LTV ventilation (P < .01). No differences in respiratory or clinical outcomes between patients with or without intraoperative LTV ventilation were observed.

Conclusions

Adherence to intraoperative LTV in surgical patients was low. Adherence of LTV intraoperatively was not associated with improved oxygenation, reductions in hospital length of stay, or in-hospital mortality. The importance of adhering to an intraoperative LTV strategy remains unclear.     

Echocardiography to predict tolerance to negative fluid balance in acute respiratory distress syndrome/acute lung injury

Purpose

In acute respiratory distress syndrome (ARDS) and acute lung injury (ALI), a conservative fluid management strategy improves lung function but could jeopardize extrapulmonary organ perfusion. The objective was to evaluate the diagnostic accuracy of echocardiography to predict tolerance of negative fluid balance (NFB) in patients with ARDS/ALI.

Materials and Methods

A prospective and observational study in an adult intensive care unit of a university hospital was conducted. All hemodynamically stable patients with ARDS/ALI were included. Echocardiography was performed before NFB and again after 24 hours. Tolerance of NFB was evaluated by the presence of hypotension, acute kidney injury, or need for fluid expansion. The 2 patient groups (tolerating and not tolerating NFB) were compared.

Results

Forty-five patients were included. Median age (Q1-Q3) was 58 (52-66) years, and the ratio of partial pressure of arterial oxygen to the fraction of inspired oxygen was 205 (163-258) mm Hg. Negative fluid balance was 1950 (1200-2200) mL within 24 hours in the tolerant group. Complications of NFB were observed in 35% cases. After univariate and multivariate logistic regression analyzes, 2 criteria was independently associates with poor tolerance: mitral inflow E wave to early diastolic mitral annulus velocities ratio (E/Ea ratio; odds ratio, 2.02 [1.02-4.02]; P = .04) and weight gain (odds ratio, 1.2 [1.03-1.4]; P = .02). The area under receiver operating characteristic curves was 0.74 for E/Ea and 0.77 for weight gain.

Conclusions

The ratio of E/Ea accurately predicted tolerance of NFB in patients with ARDS/ALI.     

Accuracy of the chest radiograph to identify bilateral pulmonary infiltrates consistent with the diagnosis of acute respiratory distress syndrome using computed tomography as reference standard

Purpose

The purpose of the study is to evaluate the diagnostic accuracy of the anteroposterior chest radiograph to detect pulmonary abnormalities consistent with acute respiratory distress syndrome (ARDS).

Materials and methods

Ninety patients who met criteria for ARDS regardless of the radiographic one and had near simultaneous chest radiograph and computed tomography (CT) performed were identified. These radiologic studies were reviewed blindly and independently by 2 radiologists for the presence or absence of bilateral pulmonary abnormalities consistent with ARDS using defined radiologic criteria. Disagreements were resolved by consensus. Using the chest CT interpretation as reference standard, the chest radiograph diagnostic parameters were calculated.

Results

Sensitivity (Se) was 0.73; specificity, 0.70; positive and negative predictive values were 0.88 and 0.47, respectively. Female sex was associated with higher Se and lower specificity. When patients were divided according to disease distribution by CT, the Se was significantly lower for focal as compared with diffuse.

Conclusions

The accuracy of the portable chest radiograph to detect pulmonary abnormalities consistent with ARDS is significantly limited. These findings suggest that the use of the chest radiograph results mainly in underrecognition of the syndrome, particularly when disease is not diffusely distributed, but also in overdiagnosis.     

Effect of type II diabetes mellitus on outcomes in patients with acute respiratory distress syndrome

Purpose

The acute respiratory distress syndrome (ARDS) is a life-threatening condition, whereas the presence of diabetes has been shown to be protective in its development. We undertook this study to assess the association of type II diabetes mellitus with clinical outcomes in patients with ARDS.

Materials and Methods

We retrospectively examined the medical records of consecutive series of patients with ARDS requiring mechanical ventilation from January 2008 to March 2011. Patients with type I diabetes were excluded from the study. Clinical outcomes such as ventilator-free days, mortality, length of stay in the hospital and intensive care unit (ICU), and reintubations were compared based on the presence of diabetes. Multivariate regression model was used to find if the presence of type II diabetes mellitus predicts ventilator-free days at day 28.

Results

Two hundred forty-nine patients with ARDS were admitted to the ICU during the study period. Fifty (20%) subjects had type II diabetes mellitus. Differences in ventilator-free days, in-hospital mortality, reintubation rate, and length of stay in the hospital or ICU were not statistically significant between diabetic and nondiabetic patients with ARDS. Acute Physiologic and Chronic Health Evaluation II, ICU specialty, use of vasopressors, and the need for reintubation were predictors of ventilator-free days at day 28. The presence of type II diabetes mellitus and its adjustment by body mass index did not show association with ventilator-free days at day 28.

Conclusions

The presence of type II diabetes mellitus is not associated with clinical outcomes in ARDS, even when its presence is adjusted by body mass index.     

Factors associated with timing of initiation of physical therapy in patients with acute lung injury

Objectives

Early initiation of physical therapy (PT) in mechanically ventilated patients is associated with improved outcomes. However, PT is frequently delayed until after extubation or discharge from the intensive care unit (ICU). We evaluated factors associated with the timing of initiation of PT in patients with acute lung injury (ALI) admitted to ICUs without an emphasis on early rehabilitation.

Design

A secondary analysis of a prospective cohort study was conducted.

Settings

The study was conducted in 11 ICUs in 3 teaching hospitals.

Patients

A total of 503 patients with ALI were included in the study.

Interventions

No interventions were used in this study.

Measurements and Main Results

Thirty-four percent of patients ever received PT. In multivariable analysis, factors associated with later PT were a higher Sequential Organ Failure Assessment score (hazard ratio, 0.89; 95% confidence interval, 0.85-0.93), higher fraction of inspired oxygen (0.97, 0.96-0.98), mechanical ventilation (0.31, 0.16-0.59), coma (0.32, 0.20-0.51), delirium (0.72, 0.50-1.03), and continuous sedation (with daily sedation interruption: 0.49, 0.30-0.81; without daily sedation interruption: 0.59, 0.39-0.89). Factors associated with earlier PT were an admitting diagnosis of trauma (3.31, 1.74-6.31) and hospital study site (2.84, 1.89-4.26).

Conclusions

In 11 ICUs without emphasis on early rehabilitation, patients with ALI frequently received no PT. Severity of illness, mental status, sedation practices, and hospital site were significant barriers to initiating PT. Understanding these barriers may be important when introducing early ICU physical rehabilitation.     

Increased plasma levels of heparin-binding protein in patients with acute respiratory distress syndrome

Introduction

Heparin-binding protein (HBP) is an antimicrobial protein stored in neutrophil granules and plays a role in endothelial permeability regulation. The aim was to assess the diagnostic and prognostic value of measuring HBP in patients with acute lung injury (ALI)/acute respiratory distress syndrome (ARDS).

Methods

Plasma HBP was collected from 78 patients with ALI/ARDS, 28 patients with cardiogenic pulmonary edema (CPE) and 20 healthy volunteers at enrollment. Levels of HBP were measured by ELISA.

Results

Patients with ALI/ARDS had significantly higher median levels of HBP compared with patients with CPE (17.15 (11.95 to 24.07) ng/ml vs. 9.50 (7.98 to 12.18) ng/ml, P <0.001) at enrollment. There was no significant difference between CPE patients and healthy subjects in terms of HBP value (P = 0.372). The HBP levels of nonsurvivors was significantly higher than that of survivors (23.90 (14.81 to 32.45) ng/ml vs. 16.01 (10.97 to 21.06) ng/ml, P = 0.012) and multivariate logistic regression showed HBP (odds ratio =1.52, P = 0.034) was the independent predictor for 30-day mortality in patients with ALI/ARDS.

Conclusions

Plasma HBP levels of ALI/ARDS patients were significantly higher than that of CPE patients. HBP was a strong prognostic marker for short-term mortality in ALI/ARDS.     

The effect of aspirin in preventing the acute respiratory distress syndrome/acute lung injury: A meta-analysis

Background

The effects of aspirin in preventing the occurrence of acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) among adult patients are controversial. We aimed to further determine the effectiveness of aspirin in reducing the rate of ARDS/ALI.

Improving the 2007 Infectious Disease Society of America/American Thoracic Society severe community-acquired pneumonia criteria to predict intensive care unit admission

Purpose

To improve 2007 Infectious Disease Society of America/American Thoracic Society (IDSA/ATS) severity criteria to predict intensive care unit (ICU) admission in patients hospitalized with pneumonia.

Methods

A composite score that included the 2007 IDSA/ATS criteria for severe pneumonia and additional significant variables identified by recent publications was tested in patients hospitalized with community-acquired pneumonia.

Results

Among 787 patients hospitalized with community-acquired pneumonia, 156 (19.8%) required admission to the ICU. We identified one major criterion (arterial pH < 7.30), and 4 minor criteria (tachycardia > 125 bpm, arterial pH 7.30-7.34, sodium < 130 mEq/L and glucose > 250 mg/dL) to be associated with ICU admission. Adding arterial pH < 7.30 to the 2 2007 IDSA/ATS major criteria increased sensitivity from 61.5% to 71.8% and area under the curve (AUC) from 0.80 to 0.86. Adding in sequence the four minor criteria to the 2007 IDSA/ATS minor criteria, increased sensitivity from 41.7% to 53.8%, and AUC from 0.65 to 0.69. In the new composite score, combining 1 of 3 major criteria with 3 of 12 minor criteria showed a sensitivity of 92.9% and an AUC of 0.88.

Conclusion

The addition of arterial pH < 7.30 to the 2007 IDSA/ATS major criteria improves sensitivity and AUC to identify patients who will require ICU care.     

Risk factors for acute respiratory distress syndrome during neutropenia recovery in patients with hematologic malignancies

Introduction

Neutropenia recovery may be associated with deterioration in oxygenation and exacerbation of pre-existing pulmonary disease. However, risk factors for acute respiratory distress syndrome (ARDS) during neutropenia recovery in patients with hematologic malignancies have not been studied.

Methods

We studied critically ill patients with hematologic malignancies with the dual objectives of describing patients with ARDS during neutropenia recovery and identifying risk factors for ARDS during neutropenia recovery. A cohort of consecutive neutropenic patients with hematologic malignancies who were admitted to the intensive care unit (ICU) was studied. During a 6-year period, 71 patients recovered from neutropenia, of whom 38 (53.5%) developed ARDS during recovery.

Results

Compared with non-ARDS patients, patients who experienced ARDS during neutropenia recovery were more likely to have pneumonia, be admitted to the ICU for respiratory failure, and receive mechanical ventilator therapy. The in-ICU mortality was significantly different between the two groups (86.8% versus 51.5%, respectively, for patients who developed ARDS during neutropenia recovery versus those who did not during neutropenia recovery). In multivariate analysis, only occurrence of pneumonia during the neutropenic episode was associated with a marked increase in the risk of ARDS (odds ratio, 4.76).

Conclusions

Patients with hematologic malignancies complicated by pneumonia during neutropenia are at increased risk for ARDS during neutropenia recovery.     

The clinical usefulness of extravascular lung water and pulmonary vascular permeability index to diagnose and characterize pulmonary edema: a prospective multicenter study on the quantitative differential diagnostic definition for acute lung injury/acute respiratory distress syndrome

Introduction

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is characterized by features other than increased pulmonary vascular permeability. Pulmonary vascular permeability combined with increased extravascular lung water content has been considered a quantitative diagnostic criterion of ALI/ARDS. This prospective, multi-institutional, observational study aimed to clarify the clinical pathophysiological features of ALI/ARDS and establish its quantitative diagnostic criteria.

Methods

The extravascular lung water index (EVLWI) and the pulmonary vascular permeability index (PVPI) were measured using the transpulmonary thermodilution method in 266 patients with PaO₂/FiO₂ ratio ≤ 300 mmHg and bilateral infiltration on chest radiography, in 23 ICUs of academic tertiary referral hospitals. Pulmonary edema was defined as EVLWI ≥ 10 ml/kg. Three experts retrospectively determined the pathophysiological features of respiratory insufficiency by considering the patients'' history, clinical presentation, chest computed tomography and radiography, echocardiography, EVLWI and brain natriuretic peptide level, and the time course of all preceding findings under systemic and respiratory therapy.

Results

Patients were divided into the following three categories on the basis of the pathophysiological diagnostic differentiation of respiratory insufficiency: ALI/ARDS, cardiogenic edema, and pleural effusion with atelectasis, which were noted in 207 patients, 26 patients, and 33 patients, respectively. EVLWI was greater in ALI/ARDS and cardiogenic edema patients than in patients with pleural effusion with atelectasis (18.5 ± 6.8, 14.4 ± 4.0, and 8.3 ± 2.1, respectively; P < 0.01). PVPI was higher in ALI/ARDS patients than in cardiogenic edema or pleural effusion with atelectasis patients (3.2 ± 1.4, 2.0 ± 0.8, and 1.6 ± 0.5; P < 0.01). In ALI/ARDS patients, EVLWI increased with increasing pulmonary vascular permeability (r = 0.729, P < 0.01) and was weakly correlated with intrathoracic blood volume (r = 0.236, P < 0.01). EVLWI was weakly correlated with the PaO₂/FiO₂ ratio in the ALI/ARDS and cardiogenic edema patients. A PVPI value of 2.6 to 2.85 provided a definitive diagnosis of ALI/ARDS (specificity, 0.90 to 0.95), and a value < 1.7 ruled out an ALI/ARDS diagnosis (specificity, 0.95).

Conclusion

PVPI may be a useful quantitative diagnostic tool for ARDS in patients with hypoxemic respiratory failure and radiographic infiltrates.

Trial registration

UMIN-CTR ID UMIN000003627     

Acute kidney injury in critical care: Experience of a conservative strategy

Purpose

Renal replacement therapy (RRT) is a major supportive treatment of acute kidney injury (AKI) in intensive care unit (ICU), but the timing of its initiation remains open to debate.

Materials and methods

We retrospectively analyzed ICU patients who had AKI associated with at least one usual RRT criteria: serum creatinine concentration greater than 300 μmol/L, serum urea concentration greater than 25 mmol/L, serum potassium concentration greater than 6.5 mmol/L, severe metabolic acidosis (arterial blood pH < 7.2), oliguria (urine output < 135 mL/8 hours or < 400 mL/24 hours), overload pulmonary edema. To estimate the risk of death associated with RRT adjusted for risk factors, we performed a marginal structural Cox model with inverse-probability-of-treatment-weighted estimator.

Results

Among 4173 patients admitted to the ICU, 203 patients fulfilled potential RRT criteria. Ninety-one patients (44.8%) received RRT and 112 (55.2%) did not. Non-RRT and RRT patients differed in terms of severity of illness: Simplified Acute Physiology Score II (55 ± 17 vs 60 ± 19, respectively; P < .05) and Sequential Organ Failure Assessment score (8 [5-10] vs 9 [7-11], respectively; P = .01).Crude analysis indicated a lower ICU mortality for non-RRT compared with RRT patients (18% vs 45%; P < .001). In the marginal structural Cox model, RRT was associated with increased mortality (P < .01).

Conclusion

A conservative approach of AKI was not associated with increased mortality.     

Neurally adjusted ventilatory assist vs pressure support ventilation in infants recovering from severe acute respiratory distress syndrome: Nested study

Objective

Neurally adjusted ventilatory assist (NAVA) is a new ventilator modality with an innovative synchronization technique. Our aim is to verify if NAVA is feasible and safe in terms of physiological and clinical variables in infants recovering from severe acute respiratory distress syndrome (ARDS).

Design

This is a pilot nested study to help future trial design.

Setting

The study was performed in third-level academic pediatric intensive care units.

Patients

Infants affected by severe ARDS requiring high-frequency ventilation and weaned with NAVA during 2010 were included. Controls (2:1 ratio) were ARDS infants weaned with pressure support ventilation (PSV) during 2008-2009 matched for age, gas exchange impairment, and weight.

Main outcome measures

The main outcome measures were the physiological and ventilator parameters and the duration of ventilator support in PSV or NAVA.

Results

Ten infants treated with NAVA and 20 with PSV were studied. Heart rate (P < .001) and mean arterial pressure (P < .001) increased less during NAVA than during PSV. Similarly, Pao₂/Fio₂ ratio decreased less in NAVA than in PSV (P < .001). Neurally adjusted ventilatory assist also resulted in lower Paco₂ (P < .001) and peak pressure (P = .001), as well as higher minute ventilation (P = .013). COMFORT score (P = .004) and duration of support were lower in NAVA than in PSV (P = .011).

Conclusions

Neurally adjusted ventilatory assist is safe and suitable in infants recovering from severe ARDS. It could provide better results than PSV and is worth to be investigated in a multicenter randomized trial.     

Prognostic factors in critically ill patients with hematologic malignancies admitted to the intensive care unit

Objective

Despite an improvement in the prognosis of patients with hematologic malignancies, the mortality of such patients transferred to the intensive care unit (ICU) is high. This study determined the predictors of mortality in a cohort of critically ill patients with hematologic malignancies admitted to the ICU.

Methods

We studied 227 critically ill patients with hematologic malignancies who were admitted to the ICU between April 2009 and December 2011. A cohort of consecutive patients with hematologic malignancies was reviewed retrospectively to identify clinically useful prognostic factors.

Results

The ICU mortality rate was 84.1%, and the in-hospital mortality rate was 89.9%. The ICU mortality was significantly higher in patients with acute leukemia than in those with other malignancies. A significant difference between survivors and nonsurvivors was found in neutropenia and its recovery during the ICU stay, presence of cardiac dysfunction, the need for an invasive mechanical ventilator, use of inotropic/vasopressor agents, platelet count, aspartate transaminase level, pH, and Acute Physiology And Chronic Health Evaluation II score. In the multivariate analysis, acute leukemia, need for invasive mechanical ventilator, use of inotropic/vasopressor agents, and Acute Physiology And Chronic Health Evaluation II scores were independently associated with a worse outcome in patients with hematologic malignancies admitted to the ICU.

Conclusion

Higher mortality in patients with hematologic malignancies admitted to the ICU is associated with more severe illness, as reflected by higher organ failure scores or respiratory or hemodynamic instability. Mortality is higher in patients with acute leukemia as compared with other hematologic malignancies.     

Atrial and brain natriuretic peptide concentrations and the response to inhaled nitric oxide in patients with acute respiratory distress syndrome

Purpose

The response to inhaled nitric oxide (iNO) is inconsistent in patients with acute respiratory distress syndrome (ARDS). We sought to determine whether the response to iNO, defined as 20% Pao₂/Fio₂ increase from baseline, depends on the level of cardiac natriuretic peptides.

Materials and methods

This is a prospective cohort study including 11 consecutive patients with ARDS who were eligible to receive iNO. Measurements of plasma concentrations of atrial natriuretic peptide (ANP), N-Terminal-Pro-B-Type Natriuretic Peptide (NT-pro-BNP) and 3′,5′-cyclic guanosine monophosphate were obtained before initiating iNO and 30 minutes later during iNO. Baseline cardiac peptides, oxygenation, and hemodynamic variables and their change during iNO were compared among responders and nonreponders to iNO.

Results

Baseline ANP and NT-pro-BNP concentrations were higher in patients that responded to iNO and tended to decrease during iNO in responders only. 3′,5′-Cyclic guanosine monophosphate concentrations were not different among responders and nonresponders and were unchanged during iNO. Baseline ANP was strongly correlated with change in intrapulmonary shunt, and baseline NT-pro-BNP and its change were correlated with the change in cardiac output.

Conclusions

High ANP and NT-pro-BNP concentrations are associated with the response to iNO. These data suggest that cardiac peptides have the potential to identify a subgroup of patients with ARDS who might derive clinical benefit from iNO.     

Plasma neutrophil gelatinase-associated lipocalin is an early marker of acute kidney injury in adult critically ill patients: A prospective study

Purpose

The aim of the study was to assess the ability of plasma neutrophil gelatinase-associated lipocalin (pNGAL) to predict acute kidney injury (AKI) in adult intensive care unit (ICU) patients.

Methods

All consecutives patients admitted to 3 ICUs were enrolled in this prospective-observational study. Plasma neutrophil gelatinase-associated lipocalin was analyzed at ICU admission. Risk, injury, failure, loss, and end-stage kidney (RIFLE) criteria were calculated at admission and for each day during the first week. Patients were classified according to whether they met the threshold for RIFLE criteria (RIFLE 0 or 1) at admission and during the first week. Four groups were identified: RIFLE (0-0), (1-1), (1-0), and (0-1).

Results

During this 1-month period, 88 patients were included in the study. Thirty-six patients met the criteria for RIFLE 0-0 with a mean pNGAL of 98 ± 60 nmol/L, 22 for RIFLE 1-1 with a mean pNGAL of 516 ± 221 nmol/L, and 20 patients had no AKI at admission but develop AKI at 48 hours (24-96 hours) (RIFLE 0-1) with a pNGAL of 342 ± 183 nmol/L. Ten patients met the criteria for RIFLE 1-0 and had a mean pNGAL of 169 ± 100 nmol/L. Using a cutoff of 155 nmol/L, sensitivity and specificity to predict AKI were 82% and 97%, respectively (area under the curve [AUC] = 0.92 [0.852-0.972]; P = .001). Looking at the patients without AKI at admission (n = 56) and who developed (n = 20) or did not develop (n = 36) AKI, receiver operating characteristic curve analysis was as follows: AUC = 0.956 (0.864-0.992). Sensitivity was 85% and specificity was 97%. Of the 7 patients who required renal replacement therapy, all of them had pNGAL of more than 303 nmol/L (AUC = 0.788 [0.687-0.868]).

Conclusion

Plasma neutrophil gelatinase-associated lipocalin at ICU admission is an early biomarker of AKI in adult ICU patients. Plasma neutrophil gelatinase-associated lipocalin increased 48 hours before RIFLE criteria.     

Lung-protective mechanical ventilation does not protect against acute kidney injury in patients without lung injury at onset of mechanical ventilation

Introduction

Preclinical and clinical studies suggest that mechanical ventilation contributes to the development of acute kidney injury (AKI), particularly in the setting of lung-injurious ventilator strategies.

Objective

To determine whether ventilator settings in critically ill patients without acute lung injury (ALI) at onset of mechanical ventilation affect the development of AKI.

Design, Setting, and Patients

Secondary analysis of a randomized controlled trial (N = 150), comparing conventional tidal volume (V_T, 10 mL/kg) with low tidal volume (V_T, 6 mL/kg) mechanical ventilation in critically ill patients without ALI at randomization. During the first 5 days of mechanical ventilation, the RIFLE class was determined daily, whereas neutrophil gelatinase–associated lipocalin and cystatin C levels were measured in plasma collected on days 0, 2, and 4.

Results

Eighty-six patients had no AKI at inclusion, and 18 patients (21%) subsequently developed AKI, but without significant difference between ventilation strategies. (Cumulative hazard, 0.26 vs 0.23; P = .88.) The courses of neutrophil gelatinase–associated lipocalin and cystatin C plasma levels did not differ significantly between randomization groups.

Conclusion

In the present study in critically patients without ALI at onset of mechanical ventilation, lower tidal volume ventilation did not reduce the development or worsening of AKI compared with conventional tidal volume ventilation.     

Duration of oral endotracheal intubation is associated with dysphagia symptoms in acute lung injury patients

Purpose

The purpose of this study is to evaluate demographic and clinical factors associated with self-reported dysphagia after oral endotracheal intubation and mechanical ventilation in patients with acute lung injury (ALI).

Materials and methods

This is a prospective cohort study of 132 ALI patients who had received mechanical ventilation via oral endotracheal tube.

Results

The primary outcome was binary, whether clinically important symptoms of dysphagia at hospital discharge were reported by patients, using the Sydney Swallowing Questionnaire score 200 or more. Of 132 patients, 29% reported clinically important symptoms of dysphagia. Of 18 relevant demographic and clinical variables, only 2 were found to be independently associated with clinically important symptoms of dysphagia in a multivariable logistic regression model: upper gastrointestinal comorbidity (odds ratio, 2.82; 95% confidence interval, 1.09-7.26) and duration of oral endotracheal intubation (odds ratio, 1.79; [95% confidence interval, 1.15-2.79] per day for first 6 days, after which additional days of intubation were not associated with a further increase in the odds of dysphagia).

Conclusions

In ALI survivors, patient-reported, postexubation dysphagia at hospital discharge was significantly associated with upper gastrointestinal comorbidity and a longer duration of oral endotracheal intubation during the first 6 days of intubation.     

Extended prone position ventilation in severe acute respiratory distress syndrome: A pilot feasibility study

Objectives

The aim of the study was to evaluate the safety of extended prone position ventilation (PPV) and its impact on respiratory function in patients with severe acute respiratory distress syndrome (ARDS).

Design

This was a prospective interventional study.

Setting

Patients were recruited from a mixed medical-surgical intensive care unit in a university hospital.

Patients

Fifteen consecutive patients with severe ARDS, previously unresponsive to positive end-expiratory pressure adjustment, were treated with PPV.

Intervention

Prone position ventilation for 48 hours or until the oxygenation index was 10 or less (extended PPV).

Results

The elapsed time from the initiation of mechanical ventilation to pronation was 35 ± 11 hours. Prone position ventilation was continuously maintained for 55 ± 7 hours. Two patients developed grade II pressure ulcers of small extent. None of the patients experienced life-threatening complications or hemodynamic instability during the procedure. The patients showed a statistically significant improvement in Pao₂/Fio₂ (92 ± 12 vs 227 ± 43, P < .0001) and oxygenation index (22 ± 5 vs 8 ± 2, P < .0001), reduction of PaCo₂ (54 ± 9 vs 39 ± 4, P < .0001) and plateau pressure (32 ± 2 vs 27 ± 3, P < .0001), and increment of the static compliance (21 ± 3 vs 37 ± 6, P < .0001) with extended PPV. All the parameters continued to improve significantly while they remained in prone position and did not change upon returning the patients to the supine position.

Conclusions

The results obtained suggest that extended PPV is safe and effective in patients with severe ARDS when it is carried out by a trained staff and within an established protocol. Extended PPV is emerging as an effective therapy in the rescue of patients from severe ARDS.