Erector Spinae Muscle Oxygen Saturation as an Early Predictor of Acute Kidney Injury in Patients Undergoing Off-Pump Coronary Artery Bypass Surgery
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 138
- 主要终点
- Predictive performance (area under the receiver operating characteristic curve, AUROC) of intraoperative erector spinae muscle regional oxygen saturation (ESrSO2) variables for postoperative acute kidney injury
研究概览
简要总结
Acute kidney injury (AKI) is a frequent and serious complication after cardiac surgery, including off-pump coronary artery bypass (OPCAB). Because AKI is diagnosed on the basis of serum creatinine, which rises 1 to 2 days after the actual renal insult, early detection and timely intervention remain difficult. Near-infrared spectroscopy (NIRS) allows non-invasive and continuous measurement of regional tissue oxygen saturation, but the effective penetration depth of commercially available devices is only approximately 2 to 2.5 cm. In most adults the renal cortex lies deeper than this, so the signal obtained from a flank sensor may originate largely from the abdominal wall musculature rather than from renal parenchyma. This limitation may explain the inconsistent association between renal regional oxygen saturation (renal rSO2) and AKI reported so far.
The erector spinae muscle at the level of the renal hilum lies within 2 cm of the skin in most patients and is supplied by the lumbar arteries and by vessels adjacent to the renal hilum. Erector spinae muscle regional oxygen saturation (ESrSO2) may therefore provide a technically more reliable NIRS signal that reflects perfusion of a vascular territory close to that of the kidney, particularly during the transient low cardiac output state induced by mechanical displacement of the heart for coronary anastomosis during OPCAB.
This single-center prospective observational cohort study will enroll 138 adult patients scheduled for elective OPCAB at Severance Hospital, Yonsei University Health System, Seoul, Republic of Korea. ESrSO2 and renal rSO2 will be measured continuously with an INVOS oximeter from before anesthetic induction until the end of surgery, in addition to cerebral rSO2, which is part of standard care at the participating institution. The ESrSO2 and renal rSO2 channels will be physically masked on the monitor display during surgery, no alarms will be set for these two channels, and their values will not be used for any intraoperative clinical decision. The recorded data will be extracted after surgery using the INVOS Analytics Tool. Apart from placement of the additional NIRS sensors and a brief pre-induction ultrasound measurement of tissue depth, no study-specific procedure, laboratory test, or imaging study will be performed, and all anesthetic, surgical, and postoperative care will follow the standard institutional protocol.
The primary objective is to identify which ESrSO2-derived variable best predicts postoperative AKI, defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria within 7 days after surgery. The candidate variables are the baseline value, the intraoperative nadir, the area under the threshold (AUT), and the duration under the threshold below absolute values of 60%, 55%, and 50% and below 80% of the baseline value, calculated separately for the period before cardiac displacement and for the cardiac displacement period. Secondary objectives are to assess whether the selected ESrSO2 variable provides independent and incremental predictive information beyond a pre-specified baseline risk model, to compare the predictive performance of ESrSO2 with that of cerebral rSO2 and renal rSO2, and to evaluate the prediction of severe AKI (KDIGO stage 2 to 3) and persistent AKI (lasting 48 hours or longer).
If ESrSO2 proves to be a useful early marker of AKI, it could allow real-time, non-invasive identification of patients at high risk during surgery and provide a basis for future trials of renal protective strategies.
详细描述
STUDY DESIGN Single-center, prospective, observational cohort study conducted at Severance Hospital, Yonsei University Health System, Seoul, Republic of Korea. There is no group allocation, no randomization, and no blinding of treatment. All participants receive the same standard anesthetic, surgical, and postoperative care regardless of study participation.
PARTICIPANTS AND SCREENING Adults aged 19 years or older scheduled for elective off-pump coronary artery bypass (OPCAB) are approached on the day before surgery. Written informed consent is obtained by an investigator in a private counseling room, with at least 3 hours allowed for consideration before consent is signed. After arrival in the operating room, willingness to participate is reconfirmed and, before anesthetic induction, ultrasonography is performed with the patient temporarily placed in the lateral decubitus position to measure the depth from the skin to the erector spinae muscle and to the renal cortex at the level of the left renal hilum. Only participants in whom the skin-to-erector spinae muscle depth is less than 2.0 cm, so that a stable NIRS measurement is considered feasible, are finally enrolled. Participants who do not meet this criterion are classified as screen failures, no sensor is applied, and no further study data are collected.
MEASUREMENTS NIRS sensors are applied over the left erector spinae muscle at the renal hilum level and over the ipsilateral renal cortex. Regional oxygen saturation is recorded continuously with an INVOS oximeter (Medtronic, Minneapolis, MN, USA), which is already installed in all operating rooms of the institution; no additional monitoring equipment is introduced for the study. Baseline values are recorded before anesthetic induction while the participant breathes room air. Recording continues until the end of surgery. The start and the end of mechanical displacement of the heart (from the deep pericardial stitch to heart return) are tagged as events, so that the period before cardiac displacement and the cardiac displacement period can be analyzed separately. The area under the threshold (AUT), defined as the integral of the magnitude and duration of desaturation below a given threshold, and the duration under the threshold are computed with the INVOS Analytics Tool Software.
OBSERVATIONAL INTEGRITY ESrSO2 and renal rSO2 are collected for research purposes only. The corresponding channel displays are physically masked during surgery, no alarms are set for these channels, and the values are not available to the clinical team and are not used for intraoperative or postoperative management. Data are retrieved after surgery from the device. Cerebral rSO2 remains part of standard institutional monitoring for OPCAB and is used and managed as usual.
DATA COLLECTED Preoperative: demographics, comorbidities, medications, New York Heart Association class, Canadian Cardiovascular Society class, EuroSCORE II, Society of Thoracic Surgeons risk score, hemodynamic variables, complete blood count and chemistry including serum creatinine, estimated glomerular filtration rate and serum albumin, echocardiography, and coronary angiography. All of these are part of the routine preoperative work-up for OPCAB and none are performed additionally for the study.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 19 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Adults aged 19 years or older scheduled for elective off-pump coronary artery bypass (OPCAB) surgery.
- •Able to receive a full explanation of the purpose and procedures of the study and to provide written informed consent voluntarily.
- •Depth from the skin to the erector spinae muscle at the level of the left renal hilum, measured by ultrasonography in the operating room before anesthetic induction, of less than 2.0 cm, so that stable near-infrared spectroscopy measurement is considered feasible. Consenting patients who do not meet this criterion are not enrolled and are classified as screen failures.
排除标准
- •Emergency surgery.
- •Concomitant surgery performed by another department.
- •Preoperative or postoperative cardiogenic shock, or need for mechanical circulatory support.
- •Estimated glomerular filtration rate below 30 mL/min/1.73 m
- •Previous kidney transplantation.
- •Left renal disease or a solitary kidney.
- •Body mass index above 30 kg/m
- •Active bleeding or active infection.
- •Inability to read and voluntarily consent to the informed consent document (for example, because of illiteracy, language barrier, or cognitive impairment).
- •Refusal to participate in the study.
研究组 & 干预措施
OPCAB cohort
Adults aged 19 years or older undergoing elective off-pump coronary artery bypass (OPCAB) surgery, in whom the skin-to-erector spinae muscle depth at the level of the left renal hilum measured by ultrasound before anesthetic induction is less than 2.0 cm. Erector spinae muscle, renal, and cerebral regional oxygen saturation are monitored continuously with near-infrared spectroscopy throughout surgery, and postoperative acute kidney injury is assessed for 7 days after surgery. A single cohort is enrolled; no comparison group is allocated, and the analysis compares participants who do and do not develop acute kidney injury within this cohort.
干预措施: Near-infrared spectroscopy monitoring of erector spinae muscle and renal regional oxygen saturation (Device)
结局指标
主要结局
Predictive performance (area under the receiver operating characteristic curve, AUROC) of intraoperative erector spinae muscle regional oxygen saturation (ESrSO2) variables for postoperative acute kidney injury
时间窗: ESrSO2 is recorded continuously from before anesthetic induction until the end of surgery (intraoperative period, up to approximately 6 hours). Acute kidney injury is assessed within 7 days after surgery.
Receiver operating characteristic curves are constructed for each candidate ESrSO2 variable and the AUROC values are calculated and compared in order to identify the variable with the highest predictive performance for acute kidney injury. Candidate variables are: (1) baseline ESrSO2 measured before anesthetic induction on room air; (2) intraoperative nadir ESrSO2; (3) area under the threshold (AUT), defined as the integral of the magnitude and duration of desaturation below a given threshold, for absolute values below 60%, 55%, and 50% and for values below 80% of baseline; and (4) duration under the same thresholds. AUT and duration under the threshold are calculated separately for the period before cardiac displacement and for the cardiac displacement period, which is defined as the interval from the deep pericardial stitch to heart return. All values are computed with the INVOS Analytics Tool Software. Acute kidney injury is defined according to the KDIGO criteria as an increase in
次要结局
- Independent and incremental predictive value of the selected ESrSO2 variable for acute kidney injury after adjustment for pre-specified established risk factors(ESrSO2 recorded intraoperatively; acute kidney injury assessed within 7 days after surgery)
- Comparison of the predictive performance (AUROC) for acute kidney injury among ESrSO2, cerebral rSO2, and renal rSO2(All regional oxygen saturation channels recorded intraoperatively; acute kidney injury assessed within 7 days after surgery)
- Predictive performance of the selected ESrSO2 variable for severe acute kidney injury (KDIGO stage 2 to 3)(Within 7 days after surgery)
- Predictive performance of the selected ESrSO2 variable for persistent acute kidney injury (lasting 48 hours or longer)(Within 7 days after surgery)
- Association between the selected ESrSO2 variable and major adverse kidney events at 30 days (MAKE-30) and days alive and out of hospital at 30 days (DAOH-30)(Within 30 days after surgery)