Intraoperative hypotension is associated with persistent acute kidney disease after noncardiac surgery: a multicentre cohort study.

BACKGROUND: Whilst intraoperative hypotension is associated with postoperative acute kidney injury (AKI), the link between intraoperative hypotension and acute kidney disease (AKD), defined as continuing renal dysfunction for up to 3 months after exposure, has not yet been studied. METHODS: We conducted a retrospective multicentre cohort study using data from noncardiac, non-obstetric surgery extracted from a US electronic health records database. Primary outcome was the association between intraoperative hypotension, at three MAP thresholds (≤75, ≤65, and ≤55 mm Hg), and the following two AKD subtypes: (i) persistent (initial AKI incidence within 7 days of surgery, with continuation between 8 and 90 days post-surgery) and (ii) delayed (renal impairment without AKI within 7 days, with AKI occurring between 8 and 90 days post-surgery). Secondary outcomes included healthcare resource utilisation for patients with either AKD subtype or no AKD. RESULTS: A total of 112 912 surgeries qualified for the study. We observed a rate of 2.2% for delayed AKD and 0.6% for persistent AKD. Intraoperative hypotension was significantly associated with persistent AKD at MAP ≤55 mm Hg (hazard ratio 1.1; 95% confidence interval: 1.38-1.22; P<0.004). However, IOH was not significantly associated with delayed AKD across any of the MAP thresholds. Patients with delayed or persistent AKD had higher healthcare resource utilisation across both hospital and intensive care admissions, compared with patients with no AKD. CONCLUSIONS: Intraoperative hypotension is associated with persistent but not delayed acute kidney disease. Both types of acute kidney disease appear to be associated with increased healthcare utilisation. Correction of intraoperative hypotension is a potential opportunity to decrease postoperative kidney injury and associated costs.

Association of perioperative hypotension with subsequent greater healthcare resource utilization.

STUDY OBJECTIVE: Determine if perioperative hypotension, a modifiable risk factor, is associated with increased postoperative healthcare resource utilization (HRU). DESIGN: Retrospective cohort study. SETTING: Multicenter using the Optum® electronic health record database. PATIENTS: Patients discharged to the ward after non-cardiac, non-obstetric surgeries between January 1, 2008 and December 31, 2017 with six months of data, before and after the surgical visit. INTERVENTIONS/EXPOSURE: Perioperative hypotension, a binary variable (presence/absence) at an absolute MAP of ≤65-mmHg, measured during surgery and within 48-h after, to dichotomize patients with greater versus lesser hypotensive exposures. MEASUREMENTS: Short-term HRU defined by postoperative length-of-stay (LOS), discharge to a care facility, and 30-day readmission following surgery discharge. Mid-term HRU (within 6 months post-discharge) quantified via number of outpatient and emergency department (ED) visits, and readmission LOS. MAIN RESULTS: 42,800 distinct patients met study criteria and 37.5% experienced perioperative hypotension. After adjusting for study covariates including patient demographics and comorbidities, patients with perioperative hypotension had: longer LOS (4.01 vs. 3.83 days; LOS ratio, 1.05; 95% CI, 1.04-1.06), higher odds of discharge to a care facility (OR, 1.18; 95% CI, 1.12-1.24; observed rate 22.1% vs. 18.1%) and of 30-day readmission (OR, 1.22; 95% CI, 1.11-1.33; observed rate 6.2% vs. 5.0%) as compared to the non-hypotensive population (all outcomes, p < 0.001). During 6-month follow-up, patients with perioperative hypotension showed significantly greater HRU regarding number of ED visits (0.34 vs. 0.31 visits; visit ratio, 1.10; 95% CI, 1.05-1.15) and readmission LOS (1.06 vs. 0.92 days; LOS ratio, 1.15; 95% CI, 1.07-1.24) but not outpatient visits (10.47 vs. 10.82; visit ratio, 0.97; 95% CI, 0.95-0.99) compared to those without hypotension. There was no difference in HRU during the 6-month period before qualifying surgery. CONCLUSIONS: We report a significant association of perioperative hypotension with an increase in HRU, including additional LOS and readmissions, both important contributors to overall medical costs.

Short and Mid-Term Economic Impact of Pulmonary Artery Catheter Use in Adult Cardiac Surgery: A Hospital and Integrated Health System Perspective.

OBJECTIVE: A monitoring pulmonary artery catheter (PAC) is utilized in approximately 34% of the US cardiac surgical procedures. Increased use of PAC has been reported to have an association with complication rates: significant decreases in new-onset heart failure (HF) and respiratory failure (RF), but increases in bacteremia and urinary tract infections. We assessed the impact of increasing PAC adoption on hospital costs among cardiac surgery patients for US-based healthcare systems. METHODS: An Excel-based economic model calculated annualized savings for a US hospital with various cardiac surgical volumes and PAC adoption rates. A second model, for an integrated payer-provider health system, analyzed outcomes/costs resulting from the cardiac surgical admission and for the treatment of persistent HF and RF complications in the year following surgery. Model inputs were extracted from published literature, and one-way and probabilistic sensitivity analyses were performed. RESULTS: For an acute care hospital with 500 procedures/year and 34% PAC adoption, annualized savings equalled $61,806 vs no PAC utilization. An increase in PAC adoption rate led to increased savings of $134,751 for 75% and $170,685 for 95% adoption. Savings ranged from $12,361 to $185,418 at volumes of 100 and 1500 procedures/year, respectively. For an integrated payer-provider health system with the base-case scenario of 3845 procedures/year and 34% PAC adoption, estimated savings were $596,637 for the combined surgical index admission and treatment for related complications over the following year. CONCLUSION: PAC utilization in adult cardiac surgery patients results in reduced costs for both acute care hospitals and payer-provider integrated health systems.

Association between perioperative fluid management and patient outcomes: a multicentre retrospective study.

BACKGROUND: Postoperative complications increase hospital length of stay and patient mortality. Optimal perioperative fluid management should decrease patient complications. This study examined associations between fluid volume and noncardiac surgery patient outcomes within a large multicentre US surgical cohort. METHODS: Adults undergoing noncardiac procedures from January 1, 2012 to December 31, 2017, with a postoperative length of stay ≥24 h, were extracted from a large US electronic health record database. Patients were segmented into quintiles based on recorded perioperative fluid volumes with Quintile 3 (Q3) serving as the reference. The primary outcome was defined as a composite of any complications during the surgical admission and a postoperative length of stay ≥7 days. Secondary outcomes included in-hospital mortality, respiratory complications, and acute kidney injury. RESULTS: A total of 35 736 patients met the study criteria. There was a U-shaped pattern with highest (Q5) and lowest (Q1) quintiles of fluid volumes having increased odds of complications and a postoperative length of stay ≥7 days (Q5: odds ratio [OR] 1.51 [95% confidence interval {CI}: 1.30-1.74], P<0.001; Q1: OR 1.20 [95% CI: 1.04-1.38], P=0.011) compared with Q3. Patients in Q5 had greater odds of more severe acute kidney injury compared with Q3 (OR 1.52 [95% CI: 1.22-1.90]; P<0.001) and respiratory complications (OR 1.44 [95% CI: 1.17-1.77]; P<0.001). CONCLUSIONS: Both very high and very low perioperative fluid volumes were associated with an increase in complications after noncardiac surgery.

Healthcare utilization and costs of cardiopulmonary complications following cardiac surgery in the United States.

PURPOSE: This study examined postoperative heart failure (HF) and respiratory failure (RF) complications and related healthcare utilization for one year following cardiac surgery. METHODS: This study identified adult patients undergoing isolated coronary artery bypass graft (CABG) and/or valve procedures from the Cerner Health Facts® database. It included patients experiencing postoperative HF or RF complications. We quantified healthcare utilization using the frequency of inpatient admissions, emergency department (ED) visits with or without hospital admission, and outpatient visits. We then determined direct hospital costs from the determined healthcare utilization. We analyzed trends over time for both HF and RF and evaluated the association between surgery type and HF complication. RESULTS: Of 10,298 patients with HF complications, 1,714 patients (16.6%) developed persistent HF; of the 10,385 RF patients, 175 (1.7%) developed persistent RF. Healthcare utilization for those with persistent complications over the one-year period following index hospital discharge comprised an average number of the following visit types: Inpatient (1.49 HF; 1.55 RF), Outpatient (2.02, 0.51), ED without hospital admission (0.33, 0.13), ED + Inpatient (0.08, 0.06). Per patient annual costs related to persistent complications of HF and RF were $20,857 and $30,745, respectively. There was a significant association between cardiac surgical type and the incidence of HF, with risk for isolated valve procedures (adjusted OR 2.60; 95% CI: 2.35-2.88) and CABG + valve procedures (adjusted OR 2.38; 95% CI: 2.17-2.61) exceeding risk for isolated CABG procedures. CONCLUSIONS: This study demonstrates that HF and RF complication rates post cardiac surgery are substantial, and complication-related healthcare utilization over the first year following surgery results in significant incremental costs. Given the need for both payers and providers to focus on healthcare cost reduction, this study fills an important gap in quantifying the mid-term economic impact of postoperative cardiac surgical complications.

Continuous electroencephalography predicts delayed cerebral ischemia after subarachnoid hemorrhage: A prospective study of diagnostic accuracy.

OBJECTIVE: Delayed cerebral ischemia (DCI) is a common, disabling complication of subarachnoid hemorrhage (SAH). Preventing DCI is a key focus of neurocritical care, but interventions carry risk and cannot be applied indiscriminately. Although retrospective studies have identified continuous electroencephalographic (cEEG) measures associated with DCI, no study has characterized the accuracy of cEEG with sufficient rigor to justify using it to triage patients to interventions or clinical trials. We therefore prospectively assessed the accuracy of cEEG for predicting DCI, following the Standards for Reporting Diagnostic Accuracy Studies. METHODS: We prospectively performed cEEG in nontraumatic, high-grade SAH patients at a single institution. The index test consisted of clinical neurophysiologists prospectively reporting prespecified EEG alarms: (1) decreasing relative alpha variability, (2) decreasing alpha-delta ratio, (3) worsening focal slowing, or (4) late appearing epileptiform abnormalities. The diagnostic reference standard was DCI determined by blinded, adjudicated review. Primary outcome measures were sensitivity and specificity of cEEG for subsequent DCI, determined by multistate survival analysis, adjusted for baseline risk. RESULTS: One hundred three of 227 consecutive patients were eligible and underwent cEEG monitoring (7.7-day mean duration). EEG alarms occurred in 96.2% of patients with and 19.6% without subsequent DCI (1.9-day median latency, interquartile range = 0.9-4.1). Among alarm subtypes, late onset epileptiform abnormalities had the highest predictive value. Prespecified EEG findings predicted DCI among patients with low (91% sensitivity, 83% specificity) and high (95% sensitivity, 77% specificity) baseline risk. INTERPRETATION: cEEG accurately predicts DCI following SAH and may help target therapies to patients at highest risk of secondary brain injury. Ann Neurol 2018;83:958-969.

Clinical Development and Implementation of an Institutional Guideline for Prospective EEG Monitoring and Reporting of Delayed Cerebral Ischemia.

Delayed cerebral ischemia (DCI) is the most common and disabling complication among patients admitted to the hospital for subarachnoid hemorrhage (SAH). Clinical and radiographic methods often fail to detect DCI early enough to avert irreversible injury. We assessed the clinical feasibility of implementing a continuous EEG (cEEG) ischemia monitoring service for early DCI detection as part of an institutional guideline. An institutional neuromonitoring guideline was designed by an interdisciplinary team of neurocritical care, clinical neurophysiology, and neurosurgery physicians and nursing staff and cEEG technologists. The interdisciplinary team focused on (1) selection criteria of high-risk patients, (2) minimization of safety concerns related to prolonged monitoring, (3) technical selection of quantitative and qualitative neurophysiologic parameters based on expert consensus and review of the literature, (4) a structured interpretation and reporting methodology, prompting direct patient evaluation and iterative neurocritical care, and (5) a two-layered quality assurance process including structured clinician interviews assessing events of neurologic worsening and an adjudicated consensus review of neuroimaging and medical records. The resulting guideline's clinical feasibility was then prospectively evaluated. The institutional SAH monitoring guideline used transcranial Doppler ultrasound and cEEG monitoring for vasospasm and ischemia monitoring in patients with either Fisher group 3 or Hunt-Hess grade IV or V SAH. Safety criteria focused on prevention of skin breakdown and agitation. Technical components included monitoring of transcranial Doppler ultrasound velocities and cEEG features, including quantitative alpha:delta ratio and percent alpha variability, qualitative evidence of new focal slowing, late-onset epileptiform activity, or overall worsening of background. Structured cEEG reports were introduced including verbal communication for findings concerning neurologic decline. The guideline was successfully implemented over 27 months, during which neurocritical care physicians referred 71 SAH patients for combined transcranial Doppler ultrasound and cEEG monitoring. The quality assurance process determined a DCI rate of 48% among the monitored population, more than 90% of which occurred during the duration of cEEG monitoring (mean 6.9 days) beginning 2.7 days after symptom onset. An institutional guideline implementing cEEG for SAH ischemia monitoring and reporting is feasible to implement and efficiently identify patients at high baseline risk of DCI during the period of monitoring.