Acute kidney injury after cardiac surgery according to Risk/Injury/Failure/Loss/End-stage,Acute Kidney Injury Network,and Kidney Disease: Improving Global Outcomes classifications

Purpose

The epidemiology of acute kidney injury (AKI) after cardiac surgery depends on the definition used. Our aims were to evaluate the Risk/Injury/Failure/Loss/End-stage (RIFLE) criteria, the AKI Network (AKIN) classification, and the Kidney Disease: Improving Global Outcomes (KDIGO) classification for AKI post–cardiac surgery and to compare the outcome of patients on renal replacement therapy (RRT) with historical data.

Methods

Retrospective analysis of 1881 adults who had cardiac surgery between May 2006 and April 2008 and determination of the maximum AKI stage according to the AKIN, RIFLE, and KDIGO classifications.

Results

The incidence of AKI using the AKIN and RIFLE criteria was 25.9% and 24.9%, respectively, but individual patients were classified differently. The area under the receiver operating characteristic curve for hospital mortality was significantly higher using the AKIN compared with the RIFLE criteria (0.86 vs 0.78, P = .0009). Incidence and outcome of AKI according to the AKIN and KDIGO classification were identical. The percentage of patients who received RRT was 6.2% compared with 2.7% in 1989 to 1990. The associated hospital mortality fell from 82.9% in 1989 to 1990 to 15.6% in 2006 to 2008.

Conclusions

The AKIN classification correlated better with mortality than did the RIFLE criteria. Mortality of patients needing RRT after cardiac surgery has improved significantly during the last 20 years.     

Mortality and complications in elderly patients undergoing cardiac surgery

Purpose

The purpose of the study was to analyze postoperative complications, mortality, and related factors of elderly patients undergoing cardiac surgery.

Methods

An observational, retrospective, and multicenter study of cardiac surgery patients, obtained from the ARIAM registry, was performed between 2008 and 2011. Clinical-surgical data, postoperative complications, and mortality were analyzed in a group of patients older than 75 years and in a younger group.

Results

A total of 4548 patients were analyzed, with 882 (19.4%) patients at least 75 years old. Elderly patients had worse functional status (New York heart Association class) and comorbidities. The complication rate was higher in the elderly group (40.4% and 33.5%, respectively; P = .0001). Mortality in the elderly was 1.1%, 12%, and 15.1% (during surgery, intensive care unit [ICU], and 30-day mortality, respectively). Thirty-day mortality in elderly patients was higher when adjusted for EuroSCORE (European System for Cardiac Operative Risk Evaluation) and cardiopulmonary bypass time.The interaction between multiorgan dysfunction syndrome (MODS) and age more than 75 years was assessed by logistic regression, obtaining an odds ratio of 9.27 (5.88-14.60) for younger patients and 29.44 (12.22-70.94) for elderly patients who died during the ICU stay.

Conclusions

Age more than 75 years is an independent risk factor for ICU mortality when adjusted for EuroSCORE and cardiopulmonary bypass time. Elderly patients also have a higher rate of complications during ICU stay. Elderly patients develop MODS more frequently and present a higher mortality rate than younger patients with MODS.     

Acute kidney injury after cardiac arrest of ventricular fibrillation and asphyxiation swine model

Purposes

The purposes of the study are to investigate the renal function in ventricular fibrillation (VF) and asphyxiation cardiac arrest in a swine model and to estimate the value of novel biomarkers in the acute kidney injury (AKI) after cardiac arrest.

Method

Thirty-two healthy inbred Wu-Zhi-Shan miniature piglets were randomized into 2 groups (n = 16 per group). Cardiac arrest was induced by programmed electric stimulation and clamping the endotracheal tube in the VF group and asphyxiation group, respectively. Cardiopulmonary resuscitation was done for return of spontaneous circulation (ROSC).

Results

One hundred percent (16/16) ROSC was observed in the VF group, and 50% (8/16) in the asphyxiation group (P < .01). All AKI biomarkers elevated significantly after ROSC. The novel biomarkers changed much earlier than the creatinine. The concentration of novel biomarkers in the asphyxiation group was higher than the VF group. Live animals had an oliguria and developed AKI. Characteristic morphological injuries in renal tissues were observed under light microscope and transmission electron microscope and were more serious in the asphyxiation group.

Conclusions

Acute kidney injury at early stage of postresuscitation is common in different causes of cardiac arrest. Asphyxiation has more severe kidney injury and gets worse prognosis.     

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.     

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.     

CHADS2 and CHA2DS2-VASc scores can predict thromboembolic events after supraventricular arrhythmia in the critically ill patients

Purpose

Prediction of arterial thromboembolic events (ATEs) in relation to supraventricular arrhythmia (SVA) has been poorly investigated in the intensive care unit (ICU). We aimed at evaluating CHADS2 and CHA2DS2-VASc scores to predict SVA-related ATE in the ICU.

Methods

We conducted a prospective observational study including all the patients except those in the postoperative course of cardiac surgery who presented SVA lasting 30 seconds or longer during their ICU stay. We looked for ATE during ICU stay, at the first and sixth month of follow-up after ICU discharge.

Results

During the 15-month study period, 108 (12.8%) of 846 ICU patients experienced SVA with 12 SVA-related ATE occurring 6 days (3; 13) (median, 10%-90% percentiles) after SVA onset. In our SVA patients, CHADS2 score was 2 (0; 5), and CHA2DS2-VASc score 3 (0; 7). Both CHADS2 (odds ratio (OR), 1.6 [1.1; 2.4]; P = .01) and CHA2DS2-VASc scores (OR, 1.4 [1.04; 1.8]; P = .03) were significantly associated with ATE onset. However, the most accurate threshold for predicting ATE was CHADS2 score of 4 or higher. Using a multivariate analysis, only patient's history of stroke was associated with ATE onset (OR, 9.2 [2.4; 35]; P = .001).

Conclusion

CHADS2 and CHA2DS2-VASc scores are predictive of SVA-related thromboembolism in the critically ill patient.     

Impact of positive fluid balance on critically ill surgical patients: A prospective observational study

Purpose

The purpose of this study is to determine the effect of postoperative fluid balance (FB) on subsequent outcomes in acute care surgery (ACS) patients admitted to the surgical intensive care unit (ICU).

Material and methods

Acute care surgery patients admitted to the surgical ICU from 06/2012 to 01/2013 were followed up prospectively. Patients were stratified by FB into FB-positive (+) and FB-negative (−) groups by surgical ICU day 5 or day of discharge from the surgical ICU.

Results

A total of 144 ACS patients met inclusion criteria. Although there was no statistically significant difference in crude mortality (11% for FB [−] vs 15.5% for FB [+]; P = .422], after adjusting for confounding factors, achieving an FB (−) status by day 5 during the surgical ICU stay was associated with an almost 70% survival benefit (adjusted odds ratio [95% confidence interval], 0.31 [0.13, 0.76]; P = .010). In addition, achieving a fluid negative status by day 1 provided a protective effect for both overall and infectious complications (adjusted odds ratio [95% confidence interval], 0.63 [0.45, 0.88]; P = .006 and 0.64 [0.46, 0.90]; P = .010, respectively).

Conclusions

In a cohort of critically ill ACS patients, achieving FB (−) status early during surgical ICU admission was associated with a nearly 70% reduction in the risk for mortality.     

Prediction of the renal replacement therapy requirement in mechanically ventilated critically ill patients by combining biomarkers for glomerular filtration and tubular damage

Purpose

Mechanically ventilated critically ill patients with high severity score indices need a very cautious therapeutic approach. Considering that inappropriate decisions on renal replacement therapy (RRT) initiation may promote unwanted adverse effects, we evaluated whether a panel of novel and traditional renal markers is superior to conventional renal marker in predicting RRT requirements in this group of patients.

Methods

This was a prospective observational study, performed at the two distinct multidisciplinary intensive care units (ICUs) of a 1000-bed tertiary hospital. Of 310 consecutive patients, 106 patients fulfilled the inclusion criteria of the study. Urinary neutrophil gelatinase–associated lipocalin (uNGAL), serum creatinine (sCr) and serum cystatin C (sCysC) were determined on ICU admission. The predictive performance of all markers for first RRT was tested and compared based on the area under the receiver operating characteristic (ROC) curves. Time-dependent ROC curves were used to assess the earlier time point where the markers presented their maximum area under the curve (AUC).

Results

All studied biomarkers and acute physiology and chronic health evaluation (APACHE) II score, were significant independent predictors of RRT (uNGAL-AUC = 0.73, sCysC-AUC = 0.76, sCr-AUC = 0.78, APACHE-AUC = 0.73, P < 0.0001). sCysC and sCr showed early maximum predictive ability within 10 days of ICU admission, while uNGAL and APACHE II score within 11 days of ICU admission. sCr combined with normalized (n)NGAL and sCysC combined with either nNGAL or uNGAL established best predictors for the RRT initiation (AUC-ROC = 0.8). Distinguishing patients without acute kidney injury (AKI) on ICU entry, the combination of sCysC and APACHE II score proved best (AUC-ROC = 0.78).

Conclusions

Specific markers of kidney dysfunction and of kidney damage can be successfully combined to increase the prognostic capability for RRT initiation. The presence of AKI affects diagnostic performance. Without an established AKI on ICU admission, future RRT requirement was better predicted by the combination of illness severity with a marker of glomerular filtration rate. With AKI on ICU admission a combination of the marker of glomerular filtration rate with one of tubular injury proved best.     

Mortality rates under the care of junior and senior surgery residents in a surgical intensive care unit/neurologic intensive care unit: A 5-year retrospective cohort study at Taoyuan Armed Forces General Hospital

Background

The quality and outcome of health care administered in intensive care units (ICUs) of teaching hospitals are dependent on a myriad of factors; however, few studies have assessed mortality rates and length of stay in surgical intensive care and neurologic intensive care units (SICU/NICU) in relation to the experience of junior and senior surgery residents.

Objective

The aim of this study was to determine whether there were differences in the outcomes of ICU patients cared for by junior surgery residents or senior surgery residents by assessing mortality rates and length of stay in the SICU/NICU.

Design

This was a retrospective cohort analysis. Mortality rates, length of SICU/NICU stay, and baseline characteristics were assessed in 2 patient groups: group 1, patients managed by junior surgical residents; group 2, patients managed by senior surgical residents. Categorical variables were compared by χ²/Fisher exact test, and continuous data (age and ICU stay) were compared using the Mann-Whitney U test. Acute Physiology and Chronic Health Evaluation II score was used for ICU prognostic models.

Setting

The Taoyuan Armed Forces General Hospital (Taoyuan, Taiwan, ROC) consists of an 8-bed SICU and an 8-bed NICU.

Patients

Data were collected from 2274 patients from January 1, 2002, to December 31, 2006, from the intensive care units (SICU/NICU) of the department of surgery.

Interventions

None.

Results

Significant differences between the 2 groups were found in total patient mortality and the duration of intensive care unit stay. Of 1806 patients in group 1, 446 (24.7%) died, whereas 83 (17.7%) of 468 in group 2 died (P = .002). The major difference of mortality rate was in the division of neurology surgery; 291 (26.6%) of 1092 patients in group 1 died, whereas 55 (19.2%) of 287 in group 2 died (P = .009), with most deaths due to spontaneous intracranial hemorrhage (P = .012) and central nervous system tumors (P = .048). Median length of SICU/NICU stay for group 1 was 3.0 days vs 3.5 days for group 2 (P = .003).

Conclusions

The quality of care of critically ill patients is improved when more experienced residents are providing care. We suggest that residents rotated into the special units such as SICU/NICU for care of critically ill patients should be at least at third year of training.     

Acute kidney injury after cardiac arrest

Aim

Cardiac arrest (CA) in humans causes warm renal ischemia-reperfusion injury, similar to animal models of ischemic acute kidney injury (AKI). We aimed to investigate the incidence and risk associations of AKI after CA, with or without post-resuscitation cardiogenic shock (PRCS).

Methods

We examined the renal outcomes of adult patients admitted to the intensive care unit (ICU), who survived for more than 48 h following successful resuscitation after CA.

Results

Of 105 patients (median age 65 years; 69% male), 58 (55.2%) had PRCS and were on vasoactive drugs beyond 24 h; and 9 (8.6%) (all of whom had PRCS) received renal replacement therapy. Only 3 (6.4%) of 47 patients without PRCS had RIFLE-‘I’/‘F’ AKI, compared to 30 (51.7%) of 58 patients with PRCS (p < 0.001). Median peak serum creatinine in the non-PRCS group was 102 μmol/L (interquartile range 85–115), compared to 155 μmol/L (interquartile range 112–267) (p < 0.001) in the PRCS group. On multivariate analysis, cumulative noradrenaline dose during the first 24 h in ICU, PRCS, and pre-CA renin–angiotensin–aldosterone-system blockade were independently associated with RIFLE-‘I’/‘F’ AKI; while higher serum lactate 12 h after CA, baseline creatinine, and PRCS were independently associated with greater rise in creatinine from pre-CA levels. Estimated time without spontaneous circulation, total adrenaline dose and initial cardiac rhythm during CA, had no independent associations with renal outcomes.

Conclusions

In the absence of PRCS, CA in isolation is uncommonly associated with significant AKI. The human kidney may be more resistant to warm ischemia-reperfusion injury than previously thought.     

A risk,injury, failure,loss, and end-stage renal failure score–based trigger for renal replacement therapy and survival after cardiac surgery

Purpose

It is controversial whether all critically ill patients with risk, injury, failure, loss, and end-stage renal failure (RIFLE) F class acute kidney injury (AKI) should receive renal replacement therapy (RRT). We reviewed the outcome of open heart surgery patients with severe RIFLE-F AKI who did not receive RRT.

Materials and Methods

We identified all patients with AKI after cardiac surgery over 4 years and obtained baseline characteristics, intraoperative details, and in-hospital outcomes. We analyzed physiologic and biochemical features at RRT initiation or at peak creatinine if no RRT was provided.

Results

We reviewed 1504 patients. Of these, 137 (9.1%) developed postoperative AKI with 71 meeting RIFLE-F criteria and 23 (32.4% of RIFLE-F cases) not receiving RRT. Compared with RRT-treated RIFLE-F patients, “no-RRT” patients had lower Acute Physiology and Chronic Health Evaluation III scores, less intra-aortic balloon pump requirements, shorter intensive care stay, and a trend toward lower mortality. At peak RIFLE score, their urinary output, arterial pH, and Pao₂/fraction of inspired oxygen ratio were all significantly higher. Their serum creatinine was also higher (304 vs 262 μmol/L; P = .02). Only 3 RIFLE-F no-RRT patients died in-hospital. Detailed review of cause and mode of death was consistent with non–RRT-preventable deaths. In contrast, 27 patients with RIFLE-R or RIFLE-I class received RRT. Compared with RRT-treated RIFLE-F patients, such RIFLE-R or RIFLE-I treated patients had a more severe presentation and higher mortality (51.8% vs 29.2%; P = .02).

Conclusions

After cardiac surgery, RRT was typically applied to patients with the most severe clinical presentation irrespective of creatinine levels. A RIFLE score–based trigger for RRT is unlikely to improve patient survival.     

Urine biochemistry in septic and non-septic acute kidney injury: a prospective observational study

Purpose

Determine whether there are unique patterns to the urine biochemistry profile in septic compared with non-septic acute kidney injury (AKI) and whether urinary biochemistry predicts worsening AKI, need for renal replacement therapy and mortality.

Materials and Methods

Prospective cohort study of critically ill patients with septic and non-septic AKI, defined by the RIFLE (Risk, Injury, Failure, Loss, End-Stage) criteria. Urine biochemistry parameters were compared between septic and non-septic AKI and were correlated with neutrophil gelatinase-associated lipocalin (NGAL), worsening AKI, renal replacement therapy (RRT), and mortality.

Results

Eighty-three patients were enrolled, 43 (51.8%) with sepsis. RIFLE class was not different between groups (P = .43). Urine sodium (UNa) < 20 mmol/L, fractional excretion of sodium (FeNa) < 1%, and fractional excretion of urea (FeU) < 35% were observed in 25.3%, 57.8%, and 33.7%, respectively. Septic AKI had lower UNa compared with non-septic AKI (P = .04). There were no differences in FeNa or FeU between groups. Urine NGAL was higher for FeNa≥1% compared to FeNa<1% (177.4 ng/mL [31.9-956.5] vs 48.0 ng/mL [21.1-232.4], P = .04). FeNa showed low correlation with urine NGAL (P = .05) and plasma NGAL (P = .14). There was poor correlation between FeU and urine NGAL (P = .70) or plasma NGAL (P = .41). UNa, FeNa, and FeU showed poor discrimination for worsening AKI, RRT and mortality.

Conclusion

Urine biochemical profiles do not discriminate septic and non-septic AKI. UNa, FeNa, and FeU do not reliably predict biomarker release, worsening AKI, RRT or mortality. These data imply limited utility for these measures in clinical practice in critically ill patients with AKI.     

Severe lactic acidosis in critically ill patients with acute kidney injury treated with renal replacement therapy

Purpose

Severe lactic acidosis (SLA) is frequent in intensive care unit (ICU) patients with acute kidney injury (AKI) treated with renal replacement therapy (RRT). The aim of the study is to describe the epidemiology of SLA in this setting.

Materials and methods

An observational single-center cohort analysis was performed on AKI patients treated with RRT. At initiation of RRT, SLA patients (serum lactate concentration > 5 mmol/L and pH < 7.35) were compared with non-SLA patients.

Results

Of the 454 patients dialyzed during the study period, 342 patients matched inclusion criteria (116 with and 226 patients without SLA). In SLA patients, lactate stabilized/decreased in 69.7% at 4 hours (P = .001) and in 81.8% during the period of 4 to 24 hours (P < .001) after initiation of RRT. Mortality during this 24-hour period was 31.0%. Intensive care unit mortality was 83.6% compared with 47.3% in non-SLA patients. Initial lactate concentration was not related to ICU mortality in SLA patients.

Conclusions

Severe lactic acidosis was frequent in AKI patients treated with RRT. Severe lactic acidosis patients were more severely ill and had higher mortality compared with patients without. During the first 24 hours of RRT, a correction of lactate concentration and acidosis was observed. In SLA patients, lactate concentration at initiation of RRT was not able to discriminate between survivors and nonsurvivors.     

Implementation of the Surviving Sepsis Campaign guidelines for severe sepsis and septic shock: We could go faster

Purpose

The aim of this study is to evaluate the feasibility of applying sepsis bundles in the intensive care unit (ICU) and their effect on outcomes.

Methods

In this prospective, observational study in a 31-bed capacity department of intensive care, we measured the time taken to perform sepsis bundle interventions in 69 consecutive patients with severe sepsis or septic shock.

Results

Compliance with the 6-hour bundle was obtained in 44 (72%) of 61 patients; these patients had a lower mortality rate (16% vs 41%, P = .04) and shorter ICU stay (median [range], 5 [3-10] vs 9 [6-19] days, P = .01) than other patients. Compliance with the 24-hour bundle was obtained in 30 (67%) of 44 eligible patients. The mortality rate and duration of ICU stay were not significantly lower in the 24-hour compliant as compared with the noncompliant group (23% vs 33% and 6 [4-11] vs 9 [6-25] days, respectively; P value is not significant). Patients who complied with the 24-hour sepsis bundle after only 12 hours had a lower mortality rate (10% vs 39%, P = .036) and shorter stay (6 [4-10] vs 9 [6-25] days, P = .055) than those who were compliant after 24 hours.

Conclusions

Correct application of the sepsis bundles was associated with reduced mortality and length of ICU stay. Earlier implementation of the 24-hour management bundle could result in better outcomes.     

Two acute kidney injury risk scores for critically ill cancer patients undergoing non-cardiac surgery

BACKGROUND:

Several risk scoures have been used in predicting acute kidney injury (AKI) of patients undergoing general or specific operations such as cardiac surgery. This study aimed to evaluate the use of two AKI risk scores in patients who underwent non-cardiac surgery but required intensive care.

METHODS:

The clinical data of patients who had been admitted to ICU during the first 24 hours of ICU stay between September 2009 and August 2010 at the Cancer Institute, Chinese Academy of Medical Sciences & Peking Union Medical College were retrospectively collected and analyzed. AKI was diagnosed based on the acute kidney injury network (AKIN) criteria. Two AKI risk scores were calculated: Kheterpal and Abelha factors.

RESULTS:

The incidence of AKI was 10.3%. Patients who developed AKI had a increased ICU mortality of 10.9% vs. 1.0% and an in-hospital mortality of 13.0 vs. 1.5%, compared with those without AKI. There was a significant difference between the classification of Kheterpal’s AKI risk scores and the occurrence of AKI (P<0.001). There was no significant difference between the number of Abelha’s AKI risk scores and the occurrence of AKI (P=0.499). Receiver operating characteristic curves demonstrated an area under the curve of 0.655±0.043 (P=0.001, 95% confidence interval: 0.571–0.739) for Kheterpal’s AKI risk score and 0.507±0.044 (P=0.879, 95% confidence interval: 0.422–0.592) for Abelha’s AKI risk score.

CONCLUSION:

Kheterpal’s AKI risk scores are more accurate than Abelha’s AKI risk scores in predicting the occurrence of AKI in patients undergoing non-cardiac surgery with moderate predictive capability.KEY WORDS: Risk factor, Acute kidney injury, Surgery     

Early prediction of acute kidney injury in patients with acute myocardial injury

Introduction

Previous studies have revealed that acute myocardial infarction (AMI) with acute kidney injury (AKI), about 17%, is strongly related to long-term mortality and heart failure. The dynamic changes in renal function during AMI are strongly related to long-term mortality and heart failure.

Objectives

Our study used clinical parameters and AKI biomarkers including neutrophil gelatinase–associated lipocalin, interleukin (IL)-6, IL-18, and cystatin C to evaluate prognostic relevance of AKI in the setting of AMI.

Methods

This prospective study was conducted from November 2009 to January 2011 and enrolled sequential 96 patients with catheter-proven AMI; it was approved by the institutional review board of Chang Gung Memorial Hospital, Taiwan (institutional review board no. 99-0140B) and conformed to the tenets of the Declaration of Helsinki. The definition of AKI is the elevation of serum creatinine of more than 0.3 mg/dL within 48 hours.

Results

Our results show that the incidence of AKI after AMI is 17.7% (17 patients). The following could be statistically related to AKI after AMI: age (P = .012), cardiac functions (Killip stage and echocardiogram; P = .003 each), Thrombolysis in Myocardial Infarction (TIMI) flow grade (P < .001), stenting (P < .001), neutrophil gelatinase–associated lipocalin (P = .005), IL-6 (P = .01), IL-18 (P = .002), and cystatin C (P = .002) in serum. The TIMI flow grade and serum cystatin C were shown to be important predictors by using multivariate analysis. Both TIMI flow lower than grade 2 and serum cystatin C of more than 1364 mg/L could be used to predict AKI (both overall correctness, 0.78). Moreover, IL-6 in serum is also associated with the major cardiovascular events after AMI (P = .02), as demonstrated in our study.

Conclusion

In conclusion, the worse TIMI flow and high plasma cystatin C can be used to predict AKI after AMI. Moreover, IL-6 can also be used as a 30-day major cardiovascular event indicator after AMI. A larger prospective and longitudinal study should follow the relationship between AKI predictors after AMI.     

A specialized post-anaesthetic care unit improves fast-track management in cardiac surgery: a prospective randomized trial

Introduction

Fast-track treatment in cardiac surgery has become the global standard of care. We compared the efficacy and safety of a specialised post-anaesthetic care unit (PACU) to a conventional intensive care unit (ICU) in achieving defined fast-track end points in adult patients after elective cardiac surgery.

Methods

In a prospective, single-blinded, randomized study, 200 adult patients undergoing elective cardiac surgery (coronary artery bypass graft (CABG), valve surgery or combined CABG and valve surgery), were selected to receive their postoperative treatment either in the ICU (n = 100), or in the PACU (n = 100). Patients who, at the time of surgery, were in cardiogenic shock, required renal dialysis, or had an additive EuroSCORE of more than 10 were excluded from the study. The primary end points were: time to extubation (ET), and length of stay in the PACU or ICU (PACU/ICU LOS respectively). Secondary end points analysed were the incidences of: surgical re-exploration, development of haemothorax, new-onset cardiac arrhythmia, low cardiac output syndrome, need for cardiopulmonary resuscitation, stroke, acute renal failure, and death.

Results

Median time to extubation was 90 [50; 140] min in the PACU vs. 478 [305; 643] min in the ICU group (P <0.001). Median length of stay in the PACU was 3.3 [2.7; 4.0] hours vs. 17.9 [10.3; 24.9] hours in the ICU (P <0.001). Of the adverse events examined, only the incidence of new-onset cardiac arrhythmia (25 in PACU vs. 41 in ICU, P = 0.02) was statistically different between groups.

Conclusions

Treatment in a specialised PACU rather than an ICU, after elective cardiac surgery leads to earlier extubation and quicker discharge to a step-down unit, without compromising patient safety.

Trial registration

ISRCTN71768341. Registered 11 March 2014.     

Expedited admission of patients decreases duration of mechanical ventilation and shortens ICU stay

Background

To determine if expedited admission (<2 hours) of critically ill patients requiring intubation and mechanical ventilation from the emergency department (ED) to the intensive care unit (ICU) decreases ICU and hospital length of stay.

Methods

Patients with respiratory failure that required intubation and mechanical ventilation who were admitted to the hospital between June 2004 and May 2006 were retrospectively identified from the Project IMPACT database. Patients were divided into 2 groups based on ED length of stay: expedited (<2 hours) or nonexpedited (>2 hours).

Results

The expedited (n = 12) and nonexpedited (n = 66) groups were comparable in demographics, medical conditions, and disease severity. Mean duration of mechanical ventilation was significantly shorter in the expedited group (28.4 hours vs 67.9 hours; P = .0431), as was mean ICU length of stay (2.4 days vs 4.9 days; P = .0209). Length of hospital stay tended to be shorter for the patients in the expedited group (6.8 days vs 8.9 days; P = .0609).

Conclusions

Expedited admission (<2 hours) of critically ill patients requiring intubation and mechanical ventilation from the ED to the ICU was associated with shorter durations of mechanical ventilation and ICU length of stay, suggesting that prompt ICU admission results in improved use of resources.     

Microcirculatory perfusion derangements during continuous hemofiltration with fixed dose of ultrafiltration in stabilized intensive care unit patients

Introduction

Acute kidney injury (AKI) is a well-known complication in critically ill patients. Little is known about the timing and the ultrafiltration dose after initial resuscitation. In vivo microscopy of the microcirculation has been suggested as alternative for the assessment of volume status. Previous studies contribute to the understanding that intravascular hypovolemia is reflected by microcirculatory blood flow changes not detected by conventional methods. The aim of our study was to assess microcirculatory blood flow changes during negative fluid balance ultrafiltration in patients with oliguric AKI.

Materials and methods

Patients with oliguric AKI on renal replacement therapy were included after hemodynamic stabilization. Target was a predefined negative fluid balance; subsequently, a stepwise decrease in amount of substitution fluid was achieved. The data were recorded at baseline and after each change.

Results

Fifteen patients were included in the study. Microcirculatory blood flow index did not change significantly between baseline and endpoint (2.90 [2.87-3.00] vs 2.90 [2.75-3.00], P = .57). During treatment, heart rate decreased from 96 (80-111) to 94 (79-110) beats per minute (P = .01), without a significant change in mean arterial blood pressure (80 [68-95 mm Hg] vs 79 [65-91 mm Hg], P = .5).

Conclusion

Microcirculatory blood flow is not altered by reduced substitution during renal replacement therapy.     

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.