Impact of individualized target mean arterial pressure for septic shock resuscitation on the incidence of acute kidney injury: a retrospective cohort study.

BACKGROUND: To examine the relationship between delta mean arterial pressure (ΔMAP; MAP change between pre-admission minus post-resuscitation) and acute kidney injury (AKI) among patients with septic shock. In this retrospective, single-center cohort study of adult patients pre-admission MAP is defined as the median MAP recorded from 365 to 7 days before admission. Post-resuscitation MAP was median MAP during the 7th hour after initiating resuscitation. RESULTS: In our cohort (N = 233; 55% male), the median (interquartile range [IQR]) age was 71 (58-81) years and the median (IQR) acute physiology, age, chronic health evaluation (APACHE) III score was 81 (66-97). Although those in the lowest ΔMAP quartile (-24.5 to 3.9 mmHg) had no demographic differences compared with the rest of the cohort, the odds ratio for AKI was 0.26 (95% CI 0.11-0.57) after adjustment for other known AKI risk factors. Among patients with a history of hypertension, the lowest quartile had an odds ratio for AKI of 0.12 (95% CI 0.04-0.37) after adjusting for risk factors for AKI in this cohort. CONCLUSIONS: The incidence of AKI was lowest among those whose post-resuscitation MAP was closest to or higher than their pre-admission MAP. Further study regarding the effect of targeting the pre-admission MAP for post-resuscitation on the incidence of AKI is warranted.

Association between mortality and replacement solution bicarbonate concentration in continuous renal replacement therapy: A propensity-matched cohort study.

BACKGROUND: Given the known deleterious effects seen with bicarbonate supplementation for acidemia, we hypothesized that utilizing high bicarbonate concentration replacement solution in continuous venovenous hemofiltration (CVVH) would be independently associated with higher mortality. METHODS: In a propensity score-matched historical cohort study conducted at a single tertiary care center from December 9, 2006, through December 31, 2009, a total of 287consecutive adult critically ill patients with Stage III acute kidney injury (AKI) requiring CVVH were enrolled. We excluded patients on maintenance dialysis, those who received other modalities of continuous renal replacement therapies, and patients that received a mixed of 22 and 32 mEq/L bicarbonate solution pre- and post-filter. The primary outcome was in-hospital and 90-day mortality rates. RESULTS: Among enrollees, 68 were used 32 mEq/L bicarbonate solution, and 219 received 22mEq/L bicarbonate solution for CVVH. Patients on 32 mEq/L bicarbonate solution were more often non-surgical, had lower pH and bicarbonate level but had higher blood potassium and phosphorus levels in comparison with those on 22 mEq/L bicarbonate solution. After adjustment for the baseline characteristics, the use of 32 bicarbonate solution was significantly associated with increased in-hospital (HR = 1.94; 95% CI 1.02-3.79) and 90-day mortality (HR = 1.50; 95% CI 1.03-2.14). There was a significant increase in the hospital (p = .03) and 90-day (p = .04) mortality between the 22 vs. 32 mEq/L bicarbonate solution groups following propensity matching. CONCLUSION: Our data showed there is a strong association between using high bicarbonate solution and mortality independent of severity of illness and comorbid conditions. These findings need to be evaluated further in prospective studies.

Association of Thrombocytopenia and Mortality in Critically Ill Patients on Continuous Renal Replacement Therapy.

BACKGROUND: Both acute kidney injury (AKI) requiring dialysis and thrombocytopenia are very common and have been independently associated with mortality and morbidity in critically ill patients. Thrombocytopenia is an independent risk factor for AKI and also a marker of disease severity. There is a paucity of literature on the prevalence, incidence, and outcome of thrombocytopenia in patients receiving continuous renal replacement therapy (CRRT). We aimed at identifying the impact of thrombocytopenia on patients in the intensive care unit (ICU) with AKI requiring CRRT. METHODS: We retrospectively studied consecutive adult patients admitted to the ICU from December 9, 2006 through December 31, 2009, with follow-up for 12 months who received CRRT. Thrombocytopenia was defined as platelet counts of <150,000/µl and severe thrombocytopenia as platelet counts of <50,000/µl. Outcomes were mortality and length of stay, both in ICU and hospital. Descriptive summary and multivariable regression model were used for data analyses. RESULTS: Out of the 541 patients studied, thrombocytopenia was observed in 350 (65%) prior to the initiation of CRRT, and 107 (20%) developed it after CRRT was started. The average age of patients was 61 ± 15; 328 (61%) were men. Sepsis was present in more than half of the patients requiring CRRT. We found a graded increase (p = 0.01) in ICU mortality with worsening platelet counts; 33, 40, and 51% of patients died in ICU with platelet counts ≥150,000/µl, 50,000-149,000/µl, and ≤50,000/µl, respectively. Thrombocytopenia prior to the initiation of CRRT and severe thrombocytopenia prior to and following the initiation of CRRT were associated with increased ICU mortality (p = 0.01). CONCLUSIONS: Thrombocytopenia is very common in ICU patients who are on CRRT, and both thrombocytopenia prior to the start of CRRT and severe thrombocytopenia developing after the initiation of CRRT significantly impact patient survival. Future large-scale prospective studies will help to explore the role of platelet in prognostication of outcome among CRRT patients.

The comparison of the commonly used surrogates for baseline renal function in acute kidney injury diagnosis and staging.

BACKGROUND: Baseline serum creatinine (SCr) level is frequently not measured in clinical practice. The aim of this study was to investigate the effect of various methods of baseline SCr determination measurement on accuracy of acute kidney injury (AKI) diagnosis in critically ill patients. METHODS: This was a retrospective cohort study. All adult intensive care unit (ICU) patients admitted at a tertiary referral hospital from January 1, 2011 through December 31, 2011, with at least one measured SCr value during ICU stay, were included in this study. The baseline SCr was considered either an admission SCr (SCrADM) or an estimated SCr, using MDRD formula, based on an assumed glomerular filtration rate (GFR) of 75 ml/min/1.73 m(2) (SCrGFR-75). Determination of AKI was based on the KDIGO SCr criterion. Propensity score to predict the likelihood of missing SCr was used to generate a simulated cohort of 3566 patients with baseline outpatient SCr, who had similar characteristics with patients whose outpatient SCr was not available. RESULTS: Of 7772 patients, 3504 (45.1 %) did not have baseline outpatient SCr. Among patients without baseline outpatient SCr, AKI was detected in 571 (16.3 %) using the SCrADM and 997 (28.4 %) using SCrGFR-75 (p < .001). Compared with non-AKI patients, patients who met AKI only by SCrADM, but not SCrGFR-75, were significantly associated with 60-day mortality (OR 2.90; 95 % CI 1.66-4.87), whereas patients who met AKI only by SCrGFR-75, but not SCrADM, had a non-significant increase in 60-day mortality risk (OR 1.33; 95 % CI 0.94-1.88). In a simulated cohort of patients with baseline outpatient SCr, SCrGFR-75 yielded a higher sensitivity (77.2 vs. 50.5 %) and lower specificity (87.8 vs. 94.8 %) for the AKI diagnosis in comparison with SCrADM. CONCLUSIONS: When baseline outpatient SCr was not available, using SCrGFR-75 as surrogate for baseline SCr was found to be more sensitive but less specific for AKI diagnosis compared with using SCrADM. This resulted in higher incidence of AKI with larger likelihood of false-positive cases.

Vascular Surgery Kidney Injury Predictive Score: A Historical Cohort Study.

OBJECTIVES: To develop a risk-prediction model for acute kidney injury (AKI) in patients undergoing vascular surgery. DESIGN: A retrospective cohort study. SETTING: A tertiary referral center. PARTICIPANTS: Participants included 845 adult patients who underwent vascular surgery between January 3, 2003, and May 29, 2008. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The median age of patients was 72 years (interquartile range 65-80 years), and 653 patients (77%) were male. AKI developed in 258 (30.5%) patients. Patients with AKI had lower estimated glomerular filtration rates (60±21 v 72±21, p<0.001), were older (73 [68-78] years v 71 [65-80] years, p = 0.01), had a higher prevalence of hypertension (81% v 73%, p = 0.02), and were more likely to undergo emergency surgery (5% v 2%, p = 0.02). Patients with AKI also received more diuretics (p<0.001) and ß-blockers (p = 0.003) prior to surgery. The multivariate AKI risk-prediction model with preoperative variables (estimated glomerular filtration rate, previous vascular interventions, use of preoperative diuretics and ß-blockers, and emergency surgery) showed an area under the receiver operating characteristic curve of 0.67 (95% confidence interval, 0.628-0.710); a model with additional intraoperative variables (procedure duration, fluid balance, and plasma and platelet transfusion) had an area under the receiver operating characteristic curve of 0.72 (95% confidence interval, 0.685-0.760). CONCLUSIONS: As AKI is a very common complication after vascular surgery, a risk-prediction model was derived to assess the likelihood of postoperative AKI. If validated in an independent cohort, this model may be used to facilitate targeted interventions in vascular surgery patients at high risk for AKI.

Development and validation of electronic surveillance tool for acute kidney injury: A retrospective analysis.

INTRODUCTION: Timely detection of acute kidney injury (AKI) facilitates prevention of its progress and potentially therapeutic interventions. The study objective is to develop and validate an electronic surveillance tool (AKI sniffer) to detect AKI in 2 independent retrospective cohorts of intensive care unit (ICU) patients. The primary aim is to compare the sensitivity, specificity, and positive and negative predictive values of AKI sniffer performance against a reference standard. METHODS: This study is conducted in the ICUs of a tertiary care center. The derivation cohort study subjects were Olmsted County, MN, residents admitted to all Mayo Clinic ICUs from July 1, 2010, through December 31, 2010, and the validation cohort study subjects were all patients admitted to a Mayo Clinic, Rochester, campus medical/surgical ICU on January 12, 2010, through March 23, 2010. All included records were reviewed by 2 independent investigators who adjudicated AKI using the Acute Kidney Injury Network criteria; disagreements were resolved by a third reviewer. This constituted the reference standard. An electronic algorithm was developed; its precision and reliability were assessed in comparison with the reference standard in 2 separate cohorts, derivation and validation. RESULTS: Of 1466 screened patients, a total of 944 patients were included in the study: 482 for derivation and 462 for validation. Compared with the reference standard in the validation cohort, the sensitivity and specificity of the AKI sniffer were 88% and 96%, respectively. The Cohen κ (95% confidence interval) agreement between the electronic and the reference standard was 0.84 (0.78-0.89) and 0.85 (0.80-0.90) in the derivation and validation cohorts. CONCLUSION: Acute kidney injury can reliably and accurately be detected electronically in ICU patients. The presented method is applicable for both clinical (decision support) and research (enrollment for clinical trials) settings. Prospective validation is required.

Incidence of Adverse Events during Continuous Renal Replacement Therapy.

BACKGROUND/AIMS: The incidence of adverse events (AEs) in adults who receive continuous renal replacement therapy (CRRT) is unknown. We report the incidence of mechanical, metabolic, and hemodynamic CRRT AEs. METHODS: This is a retrospective study of all consecutive adult patients (≥18 years) who underwent CRRT from January 1, 2007 to December 31, 2009. RESULTS: Out of 595 patients who underwent CRRT, 366 (62%) were male and 500 (84%) were Caucasian. Regional citrate anticoagulation was used in 98.6% of all patients. The most common clinically significant electrolyte derangements were ionized hypocalcemia (22%), ionized hypercalcemia (23%), and hyperphosphatemia (44%). Almost all (97%) patients had at least one additional AE including new onset hypotension (within the first hour after CRRT initiation) (43%), hypothermia (44%), new onset arrhythmias (29%), new onset anemia (31%) and thrombocytopenia (40%). CONCLUSIONS: ICU patients who require CRRT have a high incidence of AEs. Although the extent to which these complications are attributable to CRRT is not known, clinicians need to be cautious and aware of their high prevalence in this patient population.

A video to improve patient and surrogate understanding of cardiopulmonary resuscitation choices in the ICU: a randomized controlled trial.

OBJECTIVE: To determine if a video depicting cardiopulmonary resuscitation and resuscitation preference options would improve knowledge and decision making among patients and surrogates in the ICU. DESIGN: Randomized, unblinded trial. SETTING: Single medical ICU. PATIENTS: Patients and surrogate decision makers in the ICU. INTERVENTIONS: The usual care group received a standard pamphlet about cardiopulmonary resuscitation and cardiopulmonary resuscitation preference options plus routine code status discussions with clinicians. The video group received usual care plus an 8-minute video that depicted cardiopulmonary resuscitation, showed a simulated hospital code, and explained resuscitation preference options. MEASUREMENTS AND MAIN RESULTS: One hundred three patients and surrogates were randomized to usual care. One hundred five patients and surrogates were randomized to video plus usual care. Median total knowledge scores (0-15 points possible for correct answers) in the video group were 13 compared with 10 in the usual care group, p value of less than 0.0001. Video group participants had higher rates of understanding the purpose of cardiopulmonary resuscitation and resuscitation options and terminology and could correctly name components of cardiopulmonary resuscitation. No statistically significant differences in documented resuscitation preferences following the interventions were found between the two groups, although the trial was underpowered to detect such differences. A majority of participants felt that the video was helpful in cardiopulmonary resuscitation decision making (98%) and would recommend the video to others (99%). CONCLUSIONS: A video depicting cardiopulmonary resuscitation and explaining resuscitation preference options was associated with improved knowledge of in-hospital cardiopulmonary resuscitation options and cardiopulmonary resuscitation terminology among patients and surrogate decision makers in the ICU, compared with receiving a pamphlet on cardiopulmonary resuscitation. Patients and surrogates found the video helpful in decision making and would recommend the video to others.

Actual versus ideal body weight for acute kidney injury diagnosis and classification in critically ill patients.

BACKGROUND: In the current acute kidney injury (AKI) definition, the urine output (UO) criterion does not specify which body weights (BW), i.e. actual (ABW) versus ideal (IBW), should be used to diagnose and stage AKI, leading to heterogeneity across research studies. METHODS: This is a single center, retrospective, observational study conducted at a tertiary referral hospital. All adult patients who were admitted to intensive care units (ICUs) at our institution for a minimum of 6 continuous hours between January and March 2010 and had a urinary catheter for hourly urine output monitoring were eligible for this study. Patients' AKI stages, based on UO criterion, were assessed by calculating each milliliter of urine per kilogram per hour, using ABW versus IBW. RESULTS: A total of 493 ICU patients were included in the analysis. The median ABW and IBW were 82 (IQR 68-96) and 70 (IQR 60-77) kg, respectively. Using the IBW criterion, 154 patients (31.2%) were diagnosed with AKI, while 204 (41.4%) were diagnosed using the ABW measurement (P-value<.01). Patients who had AKI regardless of BW type had an adjusted odds ratio of 1.76 (95% CI 1.05-2.95) for 90-day mortality, whereas patients who had AKI according to ABW but not IBW had no significant increase in the risk of 90-day mortality, adjusted OR 0.76; (95% CI 0.25-1.91), compared to patients who had no AKI. CONCLUSIONS: Using ABW to diagnose and stage AKI by UO criterion is more sensitive and less specific than IBW. Based on the application of the definition, different BW types could be utilized.

Development, validation, and results of a survey to measure understanding of cardiopulmonary resuscitation choices among ICU patients and their surrogate decision makers.

BACKGROUND: Shared-decision-making about resuscitation goals of care for intensive care unit (ICU) patients depends on a basic understanding of cardiopulmonary resuscitation (CPR). Our objective was to develop and validate a survey to assess comprehension of CPR among ICU patients and surrogate decision-makers. METHODS: We developed a 12-item verbally-administered survey incorporating input from patients, clinicians, and expert focus groups. RESULTS: We administered the survey to 32 ICU patients and 37 surrogates, as well as to 20 resident physicians to test discriminative validity. Median (interquartile range) total knowledge scores were 7 (5-10) for patients, 9 (7-12) for surrogates, and 14.5 (14-15) for physicians (p <.001). Forty-four percent of patients and 24% of surrogates could not explain the purpose of CPR. Eighty-eight percent of patients and 73% of surrogates could not name chest compressions and breathing assistance as two components of CPR in the hospital. Forty-one percent of patients and 24% of surrogates could not name a single possible complication of CPR. Forty-three percent of participants could not specify that CPR would be performed with a full code order and 25% of participants could not specify that CPR would not be performed with a do-not-resuscitate order. Internal consistency (Cronbach's alpha = 0.97) and test-retest reliability (Pearson correlation = 0.96, p < .001) were high. CONCLUSIONS: This easily administered survey, developed to measure knowledge of CPR and resuscitation preference options among ICU patients and surrogates, showed strong face validity, content validity, internal consistency, test-retest reliability, and discriminative validity. A substantial proportion of ICU patients and surrogates decision-makers have poor knowledge of CPR and basic resuscitation options.