Practice-Based Learning and Improvement: Improving Morbidity and Mortality Review Using Natural Language Processing.

INTRODUCTION: Practice-Based Learning and Improvement, a core competency identified by the Accreditation Council for Graduate Medical Education, carries importance throughout a physician's career. Practice-Based Learning and Improvement is cultivated by a critical review of complications, yet methods to accurately identify complications are inadequate. Machine-learning algorithms show promise in improving identification of complications. We compare a manual-supplemented natural language processing (ms-NLP) methodology against a validated electronic morbidity and mortality (MM) database, the Morbidity and Mortality Adverse Event Reporting System (MARS) to understand the utility of NLP in MM review. METHODS: The number and severity of complications were compared between MARS and ms-NLP of surgical hospitalization discharge summaries among three academic medical centers. Clavien-Dindo (CD) scores were assigned to cases with identified complications and classified into minor (CD I-II) or major (CD III-IV) harm. RESULTS: Of 7774 admissions, 987 cases were identified to have 1659 complications by MARS and 1296 by ms-NLP. MARS identified 611 (62%) cases, whereas ms-NLP identified 670 (68%) cases. Less than one-third of cases (299, 30.3%) were detected by both methods. MARS identified a greater number of complications with major harm (457, 46.30%) than did ms-NLP (P < 0.0001). CONCLUSIONS: Both a prospectively maintained MM database and ms-NLP review of discharge summaries fail to identify a significant proportion of postoperative complications and overlap 1/3 of the time. ms-NLP more frequently identifies cases with minor complications, whereas prospective voluntary reporting more frequently identifies major complications. The educational benefit of reporting and analysis of complication data may be supplemented by ms-NLP but not replaced by it at this time.

Reducing surgical site infections after colectomy: bundle item compliance, process, and outlier identification.

BACKGROUND: The purpose of this study was to implement a checklist monitoring system and identify critical surgical checklist items associated with post-colectomy surgical site infections (SSI). The relationship between checklist compliance, infection rates, and identification of non-compliant surgeons was explored. MATERIALS AND METHODS: National Health Safety Network (NHSN) data were imported annually to establish baseline incidence of post-colectomy SSI from 2016 to 2019. A colectomy checklist was used to monitor compliance for 1694 random colectomies (1274 elective; 420 emergency). Reports were generated monthly to profile system, hospital, surgeon-specific infection, and checklist compliance rates. RESULTS: Checklist compliance improved in elective and emergent colectomies to > 90% for all items except oral antibiotic and mechanical bowel prep in elective cases. Annualized total SSI and organ space infection rates in elective cases decreased by 33% and 45%, respectively. Elective and emergency SSI's were reduced for Superficial Incisional Primary (SIP), Deep Incisional Primary (DIP), and Intra-Abdominal Abscess (IAB) by 66%, 60.4%, and 78.3%, respectively. Checklist compliance between low (< 3%) and high (> 3%) infection rate surgeons demonstrated significantly lower utilization of oral antibiotic prep (p < 0.03) and mechanical bowel prep (p < 0.02) in high infection rate surgeons. CONCLUSION: Surgeons compliant with colectomy checklists decreased elective and emergency colectomy infection rates. Ceiling compliance rates > 95% for bundle items are suggested to achieve optimal reductions in SSIs and efforts should be focused on surgeons with NHSN infection rates > 3%. Oral antibiotic prep and mechanical bowel prep compliance rates in elective colectomy appeared to differentiate high infection rate surgeons from low infection rate surgeons.

Blinded intraoperative skill evaluations avoid gender-based bias.

INTRODUCTION: Gender bias has been identified consistently in written performance evaluations. Qualitative tools may provide a standardized way to evaluate surgical skill and minimize gender bias. We hypothesized that there is no difference in operative time or GEARS scores in robotic hysterectomy for men vs women surgeons. METHODS: Patients undergoing robotic hysterectomies performed between June 2019 and March 2020 at 8 hospitals within the same hospital system were captured into a prospective database. GEARS scores were assigned by crowd-sourced evaluators by a third party blinded to any surgeon- or patient-identifying information. One-way ANOVA was used to compare the mean operative time and GEARS scores for each group, and significant variables were included in a one-way ANCOVA to control for confounders. Two-tailed p-value < 0.05 was considered significant. RESULTS: Seventeen women and 13 men performed a total of 188 hysterectomies; women performed 34 (18%) and men performed 153 (81%). Women surgeons had a higher mean operative time (133 ± 58 vs 86.3 ± 46 min, p = 0.024); after adjustment, there were no significant differences in operative time (p = 0.607). There was no significant difference between the genders in total GEARS score (20.0 ± 0.77 vs 20.2 ± 0.70, p = 0.415) or GEARS subcomponent scores: bimanual dexterity (3.98 ± 0.03 vs 4.00 ± 0.03, p = 0.705); depth perception (4.04 ± 0.04 vs 4.05 ± 0.02, p = 0.799); efficiency (3.79 ± 0.02 vs 3.82 ± 0.02, p = 0.437); force sensitivity (4.01 ± 0.04 vs 4.05 ± 0.05, p = 0.533); or robotic control (4.16 ± 0.03 vs 4.26 ± 0.01, p = 0.079). CONCLUSION: There was no difference in GEARS score between men vs women surgeons performing robotic hysterectomies. Video-based blinded assessment of skills may minimize gender biases when evaluating surgical skill for competency evaluation and credentialing.

Core Competency Self-Assessment Enhances Critical Review of Complications and Entrustable Activities.

BACKGROUND: The Accreditation Council for Graduate Medical Education has defined six core competencies (CCs) that every successful physician should possess. However, the assessment of CC achievement among trainees is difficult. This project was designed to prospectively evaluate the impact of resident identification of CC as a component of morbidity review on error identification and standard of care (SOC) assessments. The platform was assessed for its reliability as a measure of resident critical analysis of complication causality across postgraduate year (PGY). MATERIALS AND METHODS: A total of 1945 general surgery cases with complications were assessed for error identification and SOC management between January 1, 2016, and December 31, 2018. CC identification was additionally assessed between January 1, 2019, and December 31, 2019, and included 708 general surgery cases. Data were evaluated for error assessments and overall SOC management. PGY4 and 5 residents were compared for number of cases and complications reviewed, severity, error causation, and CC relevance. RESULTS: Study groups were equivalent by Clavien-Dindo scores. Error identification significantly increased in all categories: diagnostic (P < 0.001), technical (P < 0.05), judgment (P < 0.001), system (P < 0.001), and communication (P < 0.001). Overall SOC assessments validated by a supervising surgical quality officer were unchanged. An increased exposure to cases with severe complications, error causation, and CC relevance was noted across PGY. CONCLUSIONS: The addition of CC assessment into morbidity review appears to improve the critical thinking of evaluating residents by increasing the identification of management errors. Used as an element of prospective self-assessment, teaching residents to identify CC principles in cases with complications may assist in learner progression toward clinical competence and critical thinking.

Cognitive Bias Impact on Management of Postoperative Complications, Medical Error, and Standard of Care.

BACKGROUND: Cognitive bias (CB) is increasingly recognized as an important source of medical error and up to 75% of errors in internal medicine are thought to be cognitive in origin (O'Sullivan ED, Schofield SJ. Cognitive bias in clinical medicine. J R Coll Physicans Edinb. 2018;48;225-232). However, primary data regarding the true incidence of bias is lacking. A prospective evaluation of CB in the management of surgical cases with complications has not been reported. This study reports the incidence and distribution of various types of CBs, and evaluates their impact on management errors and standard of care (SOC). METHODS: A prospectively collected series of 736 general surgical cases with complications from three university hospitals was analyzed. Surgical residents evaluated cases for 22 types of CBs (Croskerry P. The importance of cognitive errors in diagnosis and strategies to minimize them. Acad Med. 2003;78:775-780). Supervising quality officers validated all quality assessments. Data were assessed for the incidence of CBs, error assessments (diagnostic, technical, judgment, system, communication, therapeutic, and professionalism), and SOC. RESULTS: CB was attributed in 32.7% (241/736) of all cases with complications. The most common CBs identified, both singly and in groups, were anchoring, confirmation, omission, commission, overconfidence, premature closure, hindsight, diagnosis momentum, outcome, and ascertainment bias. The attribution of CB was correlated to a statistically significant increase in the incidence of management errors by the surgical team and lower SOC assessments. CONCLUSIONS: CBs are identified in the management of cases with complications and are associated with an increase in management errors and a degradation in SOC. Insight into the types of CBs and their association with the type and severity of management errors may prove useful in improving quality care.

Correlation between operative time and crowd-sourced skills assessment for robotic bariatric surgery.

INTRODUCTION: Operative time has been traditionally used as a proxy for surgical skill and is commonly utilized to measure the learning curve, assuming that faster operations indicate a more skilled surgeon. The Global Evaluative Assessment of Robotic Skills (GEARS) rubric is a validated Likert scale for evaluating technical skill. We hypothesize that operative time will not correlate with the GEARS score. METHODS: Patients undergoing elective robotic sleeve gastrectomy at a single bariatric center of excellence hospital from January 2019 to March 2020 were captured in a prospectively maintained database. For step-specific scoring, videos were broken down into three steps: ligation of short gastric vessels, gastric transection, and oversewing the staple line. Overall and step-specific GEARS scores were assigned by crowd-sourced evaluators. Correlation between operative time and GEARS score was assessed with linear regression and calculation of the R2 statistic. RESULTS: Sixty-eight patients were included in the study, with a mean operative time of 112 ± 27.4 min. The mean GEARS score was 20.1 ± 0.81. Mean scores for the GEARS subcomponents were: bimanual dexterity 4.06 ± 0.17; depth perception 3.96 ± 0.24; efficiency 3.82 ± 0.19; force sensitivity 4.06 ± 0.20; robotic control 4.16 ± 0.21. Operative time and overall score showed no correlation (R2 = 0.0146, p = 0.326). Step-specific times and scores showed weak correlation for gastric transection (R2 = 0.0737, p = 0.028) and no correlation for ligation of short gastric vessels (R2 = 0.0262, p = 0.209) or oversewing the staple line (R2 = 0.0142, p = 0.344). CONCLUSIONS: Operative time and crowd-sourced GEARS score were not correlated. Operative time and GEARS scores measure different performance characteristics, and future studies should consider using both a validated skills assessment tool and operative time for a more complete evaluation of skill.

Clinical Mortality in a Large COVID-19 Cohort: Observational Study.

BACKGROUND: Northwell Health, an integrated health system in New York, has treated more than 15,000 inpatients with COVID-19 at the US epicenter of the SARS-CoV-2 pandemic. OBJECTIVE: We describe the demographic characteristics of patients who died of COVID-19, observation of frequent rapid response team/cardiac arrest (RRT/CA) calls for non-intensive care unit (ICU) patients, and factors that contributed to RRT/CA calls. METHODS: A team of registered nurses reviewed the medical records of inpatients who tested positive for SARS-CoV-2 via polymerase chain reaction before or on admission and who died between March 13 (first Northwell Health inpatient expiration) and April 30, 2020, at 15 Northwell Health hospitals. The findings for these patients were abstracted into a database and statistically analyzed. RESULTS: Of 2634 patients who died of COVID-19, 1478 (56.1%) had oxygen saturation levels ≥90% on presentation and required no respiratory support. At least one RRT/CA was called on 1112/2634 patients (42.2%) at a non-ICU level of care. Before the RRT/CA call, the most recent oxygen saturation levels for 852/1112 (76.6%) of these non-ICU patients were at least 90%. At the time the RRT/CA was called, 479/1112 patients (43.1%) had an oxygen saturation of <80%. CONCLUSIONS: This study represents one of the largest reviewed cohorts of mortality that also captures data in nonstructured fields. Approximately 50% of deaths occurred at a non-ICU level of care despite admission to the appropriate care setting with normal staffing. The data imply a sudden, unexpected deterioration in respiratory status requiring RRT/CA in a large number of non-ICU patients. Patients admitted at a non-ICU level of care suffered rapid clinical deterioration, often with a sudden decrease in oxygen saturation. These patients could benefit from additional monitoring (eg, continuous central oxygenation saturation), although this approach warrants further study.

Methods for reducing sepsis mortality in emergency departments and inpatient units.

BACKGROUND: As part of a zero-tolerance approach to preventable deaths, North Shore-LIJ Health System (North Shore-LIJ) leadership prioritized a major patient safety initiative to reduce sepsis mortality in 2009 across 10 acute care hospitals (an 11th joined later). At baseline (2008), approximately 3,500 patients were discharged with a diagnosis of sepsis, which ranked as the top All Patient Refined Diagnosis-Related Group by number of deaths (N = 883). Initially, the focus was sepsis recognition and treatment in the emergency departments (EDs). METHODS: North Shore-LIJ, the 14th largest health care system in the United States, cares for individuals at every stage of life at 19 acute care and specialty hospitals and more than 400 outpatient physician practice sites throughout New York City and the greater New York metropolitan area. The health system launched a strategic partnership with the Institute for Healthcare Improvement (IHI) in August 2011 to accelerate the pace of sepsis improvement. Throughout the course of the initiative, North Shore-LIJ collaborated with many local, state, national, and international organizations to test innovative ideas, share evidence-based best practices, and, more recently, to raise public awareness. RESULTS: North Shore-LIJ reduced overall sepsis mortality by approximately 50% in a six-year period (2008-2013; sustained through 2014) and increased compliance with sepsis resuscitation bundle elements in the EDs and inpatient units in the 11 acute care hospitals. CONCLUSION: Improvements were achieved by engaging leadership; fostering interprofessional collaboration, collaborating with other leading health care organizations; and developing meaningful, real-time metrics for all levels of staff.

The effectiveness of land based exercise compared to decompressive surgery in the management of lumbar spinal-canal stenosis: a systematic review.

BACKGROUND: Lumbar spinal stenosis (LSS) is prevalent in those over the age of 65 years and the leading cause of spinal surgery in this population. Recent systematic reviews have examined the effectiveness of conservative management for LSS, but not relative to surgical interventions. The aim of this review was to systematically examine the effectiveness of land based exercise compared with decompressive surgery in the management of patients with LSS. METHODS: A systematic review of randomised controlled trials and clinical trials was undertaken. The databases MEDLINE, Embase, CINAHL, PEDro and Cochrane Library Register of Controlled Trials were searched from January 2000 to June 2011. Only studies that included subjects with lumbar spinal canal stenosis were considered in this review. Studies also had to use a patient reported functional outcome measure for a land based exercise intervention or lumbar decompressive surgery. RESULTS: Only one study compared the effectiveness of exercise and decompressive surgery for LSS. Surgery demonstrated statistically significant improvements in patient reported functional outcome scores at 6, 12 and 24-months post-intervention (p < 0.01). To facilitate further analysis, the results from 12 exercise and 10 surgical intervention arms were compared using percentage change in patient reported functional outcome measure scores. Exercise interventions showed initial improvements, ranging from 16 to 29% above baseline. All decompressive surgical interventions demonstrated greater and sustained improvements over 2-years (range 38-67% improvement) with moderate to large effect sizes. The most commonly reported complications associated with surgery were dural tears, while details of adverse effects were lacking in exercise interventions. CONCLUSIONS: This systematic review of the recent literature demonstrates that decompressive surgery is more effective than land based exercise in the management of LSS. However, given the condition's slowly progressive nature and the potential for known surgical complications, it is recommended that a trial of conservative management with land based exercise be considered prior to consideration of surgical intervention.

Mortality of Mechanically Ventilated COVID-19 Patients in Traditional versus Expanded Intensive Care Units in New York.

Rationale: During the first wave of the coronavirus disease (COVID-19) pandemic in New York City, the number of mechanically ventilated COVID-19 patients rapidly surpassed the capacity of traditional intensive care units (ICUs), resulting in health systems utilizing other areas as expanded ICUs to provide critical care. Objectives: To evaluate the mortality of patients admitted to expanded ICUs compared with those admitted to traditional ICUs. Methods: Multicenter, retrospective, cohort study of mechanically ventilated patients with COVID-19 admitted to the ICUs at 11 Northwell Health hospitals in the greater New York City area between March 1, 2020 and April 30, 2020. Primary outcome was in-hospital mortality up to 28 days after intubation of COVID-19 patients. Results: Among 1,966 mechanically ventilated patients with COVID-19, 1,198 (61%) died within 28 days after intubation, 46 (2%) were transferred to other hospitals outside of the Northwell Health system, 722 (37%) survived in the hospital until 28 days or were discharged after recovery. The risk of mortality of mechanically ventilated patients admitted to expanded ICUs was not different from those admitted to traditional ICUs (hazard ratio [HR], 1.07; 95% confidence interval [CI], 0.95-1.20; P = 0.28), while hospital occupancy for critically ill patients itself was associated with increased risk of mortality (HR, 1.28; 95% CI, 1.12-1.45; P < 0.001). Conclusions: Although increased hospital occupancy for critically ill patients itself was associated with increased mortality, the risk of 28-day in-hospital mortality of mechanically ventilated patients with COVID-19 who were admitted to expanded ICUs was not different from those admitted to traditional ICUs.

An inpatient fall prevention initiative in a tertiary care hospital.

BACKGROUND: In response to increasing inpatient fall rates, which reached 3.9 falls per 1000 inpatient-days in the last quarter of 2005, Staten Island University Hospital, a 714-bed, tertiary care hospital (Staten Island, New York), implemented a fall prevention initiative (FPI). The initiative was intended to decrease inpatient falls and associated injury by institutionalizing staff safety awareness; accountability, and critical thinking; eradicating historically acceptable system failures; and mandating a critical evaluation of safety precautions and application of fall prevention protocol. METHODS: The intervention included two phases (1) a review phase, in which existing fall prevention efforts were evaluated, and (2) the FPI implementation phase, in which systems were implemented to ensure fall risk assessments, fall incident investigations, identifying and confronting problem issues, planning and adherence to corrective action, and accountability for missed preventive opportunities. For all 1,098,471 inpatient-days of persons aged 18 years and older, with an admission lasting at least one day, between April 2006 and March 2010, data were collected for inpatient falls and fall-associated injuries per 1000 inpatient-days. RESULTS: Four-year inpatient fall rates decreased by 63.9% (p < .0001); the greatest reduction (72.3%) occurred between the first quarter (Q1) 2005 and Q4 2009. Minor and moderate fall-related injuries significantly decreased by 54.4% and 64.0%, respectively. Two falls with major injury occurred during the study. CONCLUSIONS: The FPI was associated with a significant reduction in fall and fall-related injury rates. The results suggest that increasing commitment to continuous quality improvement through enhanced safety awareness and accountability contributed to the initiative's success and led to a change of normative behavior and a culture of safety.

Cognitive bias and severity of harm following surgery: Plan for workflow debiasing strategy.

INTRODUCTION: This study analyzes the relationship between cognitive bias (CB) and harm severity as measured by Clavien-Dindo Scores (CD). METHODS: A prospectively collected series of 655 severity matched general surgical cases with complications were analyzed. Cases were evaluated for CB and assigned harm scores as defined by CD grade. Potentially mitigating "debiasing" strategies were identified for each bias attribution. RESULTS: Among cases with CB, 24% (55/232) were CD(I-II) and 76% (177/232) were CD(III-V). Odds ratio suggests that serious complications occur nearly 60% more frequently when CB is identified. The CBs identified with severe harm were Overconfidence, Commission, Anchoring, Confirmation, and Diagnosis Momentum. Preliminary data on debiasing strategies suggest diagnosis review, linear reasoning and Type II thinking may be relevant in over 85% of complications. CONCLUSION: The incidence of CB is increased in patients sustaining severe harm. Understanding the specific CBs identified and their mitigating debiasing strategies may improve outcomes.

Early Experience With Neutralizing Monoclonal Antibody Therapy for COVID-19: Retrospective Cohort Survival Analysis and Descriptive Study.

BACKGROUND: Neutralizing monoclonal antibody (MAB) therapies may benefit patients with mild to moderate COVID-19 at high risk for progressing to severe COVID-19 or hospitalization. Studies documenting approaches to deliver MAB infusions and demonstrating their efficacy are lacking. OBJECTIVE: We describe our experience and the outcomes of almost 3000 patients who received MAB infusion therapy at Northwell Health, a large integrated health care system in New York. METHODS: This is a descriptive study of adult patients who received MAB therapy between November 20, 2020, to January 31, 2021, and a retrospective cohort survival analysis comparing patients who received MAB therapy prior to admission versus those who did not. A multivariable Cox model with inverse probability weighting according to the propensity score including covariates (sociodemographic, comorbidities, and presenting vital signs) was used. The primary outcome was in-hospital mortality; additional evaluations included emergency department use and hospitalization within 28 days of a positive COVID-19 test for patients who received MAB therapy. RESULTS: During the study period, 2818 adult patients received MAB infusion. Following therapy and within 28 days of a COVID-19 test, 123 (4.4%) patients presented to the emergency department and were released, and 145 (5.1%) patients were hospitalized. These 145 patients were compared with 200 controls who were eligible for but did not receive MAB therapy and were hospitalized. In the MAB group, 16 (11%) patients met the primary outcome of in-hospital mortality, versus 21 (10.5%) in the control group. In an unadjusted Cox model, the hazard ratio (HR) for time to in-hospital mortality for the MAB group was 1.38 (95% CI 0.696-2.719). Models adjusting for demographics (HR 1.1, 95% CI 0.53-2.23), demographics and Charlson Comorbidity Index (HR 1.22, 95% CI 0.573-2.59), and with inverse probability weighting according to propensity scores (HR 1.19, 95% CI 0.619-2.29) did not demonstrate significance. The hospitalization rate was 4.4% for patients who received MAB therapy within 0 to 4 days, 5% within 5 to 7 days, and 6.1% in ≥8 days of symptom onset (P=.15). CONCLUSIONS: Establishing the capability to provide neutralizing MAB infusion therapy requires substantial planning and coordination. Although this therapy may be an important treatment option for early mild to moderate COVID-19 in patients who are at high risk, further investigations are needed to define the optimal timing of MAB treatment to reduce hospitalization and mortality.

Alternative instrumentation for the analysis of total carbon dioxide (TCO(2)) in equine plasma.

The analysis of total carbon dioxide (TCO(2)) in equine plasma is conventionally done in Australia and elsewhere using Beckman Synchron EL-ISE(R) analysers. This instrument is no longer being manufactured and has not been supported by the supplier since December 2008. For testing for TCO(2) to continue, it is necessary to evaluate and commission alternative instrumentation. In this paper, we compare the Beckman Synchron EL-ISE, the Beckman Synchron CX5, the Beckman UniCel DxC 600 and the Randox Daytona instruments. Results indicate that all four instruments perform in accordance with the manufacturer's specifications. The Beckman CX 5, DxC 600 and Randox Daytona instruments are therefore all suitable alternatives for routine screening in a laboratory environment. Only the Randox Daytona instrument is sufficiently 'portable', i.e. it can be readily transported and used on-site at a racecourse (typically in a purpose-built modest-size laboratory vehicle). The three Beckman instruments are suitable for 'confirmatory analysis' using the quality-accredited method (Racing Science Centre), but the principle of operation of the Randox Daytona instrument may preclude its use in confirmatory analysis. Instrument costs may affect purchase decisions.

Clinical Mortality Review in a Large COVID-19 Cohort.

BACKGROUND: Northwell Health (Northwell), an integrated health system in New York, treated more than 15000 inpatients with coronavirus disease (COVID-19) at the US epicenter of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. We describe the demographic characteristics of COVID-19 mortalities, observation of frequent rapid response teams (RRT)/cardiac arrest (CA) calls for non-intensive care unit (ICU) patients, and factors that contributed to RRT/CA calls. METHODS: A team of registered nurses reviewed medical records of inpatients who tested positive for SARS-CoV-2 via polymerase chain reaction (PCR) before or on admission and died between March 13 (first Northwell inpatient expiration) and April 30, 2020 at 15 Northwell hospitals. Findings for these patients were abstracted into a database and statistically analyzed. FINDINGS: Of 2634 COVID-19 mortalities, 56.1% had oxygen saturation levels greater than or equal to 90% on presentation and required no respiratory support. At least one RRT/CA was called on 42.2% of patients at a non-ICU level of care. Before the RRT/CA call, the most recent oxygen saturation levels for 76.6% of non-ICU patients were at least 90%. At the time RRT/CA was called, 43.1% had an oxygen saturation less than 80%. INTERPRETATION: This study represents one of the largest cohorts of reviewed mortalities that also captures data in non-structured fields. Approximately 50% of deaths occurred at a non-ICU level of care, despite admission to the appropriate care setting with normal staffing. The data imply a sudden, unexpected deterioration in respiratory status requiring RRT/CA in a large number of non-ICU patients. Patients admitted to a non-ICU level of care suffer rapid clinical deterioration, often with a sudden decrease in oxygen saturation. These patients could benefit from additional monitoring (eg, continuous central oxygenation saturation), although this approach warrants further study.