Relationship Between Permissive Hypotension and Acute Kidney Injury in Rhinologic Surgeries: Evaluation With Serum NGAL and Cystatin C Levels
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 35
- 试验地点
- 1
- 主要终点
- Change in plasma NGAL and cystatin C concentrations indicating subclinical kidney injury
研究概览
简要总结
This study aims to investigate the effects of permissive hypotension, which is routinely used in rhinologic surgeries such as rhinoplasty, septoplasty, and functional endoscopic sinus surgery (FESS), on renal function. Although permissive hypotension has been widely practiced to improve surgical field visibility and reduce intraoperative blood loss, its specific definition is not standardized in the literature. In most studies, maintaining mean arterial pressure (MAP) within the range of 50-65 mmHg is considered permissive hypotension. MAP values below 60 mmHg have been associated with increased risk of cardiac and renal complications. However, in otherwise healthy patients, such episodes are frequently tolerated without clinically apparent renal dysfunction.
The kidneys have a strong compensatory reserve capacity, and early tubular injury may not be detected by conventional renal function tests such as serum creatinine. Therefore, the use of more sensitive biomarkers is necessary to detect potential subclinical injury.
In this prospective observational study, serum NGAL and cystatin C levels will be measured from routine preoperative and postoperative (12-24 hours) blood samples obtained from adult patients undergoing rhinologic procedures. A ≥25% increase in these biomarkers from baseline will be considered indicative of subclinical acute kidney injury.
Additionally, intraoperative hemodynamic data will be monitored, and the duration of MAP <60 mmHg and MAP <65 mmHg will be recorded. At the end of the procedure, surgical field conditions will be evaluated using the Boezaart Surgical Field Score. The relationship between these parameters and biomarker changes will be analyzed.
The goal of this study is to determine whether early, clinically silent renal injury may occur during permissive hypotension and to provide insight into its potential implications for future renal function. All interventions and blood samplings are part of routine care, and no additional procedures will be performed for research purposes.
详细描述
Permissive hypotension is a commonly used anesthetic technique in rhinologic surgeries to optimize surgical conditions by reducing bleeding and improving visualization. Although widely applied, a standardized definition is lacking in the literature. Many studies define permissive hypotension as maintaining mean arterial pressure (MAP) between 50-65 mmHg. MAP values lower than 60 mmHg may compromise tissue perfusion and oxygenation, particularly in the renal medulla, possibly predisposing patients to ischemic stress. Despite this, in patients without significant comorbidities, these controlled reductions typically do not result in clinically evident kidney dysfunction, which supports the continued use of this technique in suitable cases.
However, due to the high renal reserve, subclinical kidney injury may still occur without notable changes in serum creatinine or urine output. The early detection of renal injury may be possible through biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C, which are more sensitive to structural renal injury. This study is designed to evaluate such potential biomarker changes during permissive hypotension applied for rhinologic surgery.
Study Design and Methods: This is a prospective observational, single-center study including 35 adult patients aged 18-65 years who are scheduled to undergo elective rhinoplasty, septoplasty, or FESS. Patients with a history of chronic kidney disease, uncontrolled hypertension or diabetes mellitus, or contraindications to hypotensive anesthesia will be excluded. Informed consent will be obtained preoperatively. All blood sampling and hemodynamic monitoring will be performed as part of routine clinical care, and no additional intervention will be introduced.
Data Collection and Measurements: Preoperative routine blood samples will be analyzed for renal biomarkers including serum NGAL and cystatin C, in addition to standard biochemistry profiles. Serum NGAL levels will be measured using a validated ELISA method (Elabscience, USA), and serum cystatin C levels will be analyzed using the Siemens Atellica Neph 630 analyzer with a nephelometric method.
Intraoperative hemodynamic variables will be recorded every 5 minutes throughout anesthesia, and total durations of MAP <60 mmHg and MAP <65 mmHg will be calculated. Postoperatively, between 12 and 24 hours, routine blood sampling will again be performed, and NGAL and cystatin C levels will be re-evaluated. At the end of surgery, surgical field visibility will be assessed by the otorhinolaryngology surgical team using the Boezaart Surgical Field Score.
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
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Adults aged 18-65 years
- •Scheduled for elective rhinologic surgery (rhinoplasty, septoplasty, or functional endoscopic sinus surgery)
- •ASA physical status I-II
- •Able to provide written informed consent
- •Undergoing controlled hypotension anesthesia as part of routine clinical management
排除标准
- •Known chronic kidney disease (baseline creatinine above normal range or documented CKD)
- •Uncontrolled hypertension or uncontrolled diabetes mellitus
- •Contraindications to controlled hypotensive anesthesia
- •Pregnant or breastfeeding women
- •History of major cardiovascular disease affecting renal perfusion (e.g., severe heart failure)
- •Use of nephrotoxic medications preoperatively that may interfere with renal biomarker interpretation
- •Perioperative complications requiring deviation from routine anesthetic management (e.g., major bleeding or hemodynamic instability)
结局指标
主要结局
Change in plasma NGAL and cystatin C concentrations indicating subclinical kidney injury
时间窗: Preoperative baseline to postoperative 12-24 hours
Plasma neutrophil gelatinase-associated lipocalin (NGAL) concentration (ng/mL) measured by ELISA assay and plasma cystatin C concentration (mg/L) measured by automated nephelometric assay will be assessed preoperatively and at postoperative 12-24 hours. A relative increase of ≥25% from baseline in either biomarker will be used to define subclinical renal injury.
次要结局
- Duration of mean arterial pressure below 60 mmHg during anesthesia(Intraoperative period)
- Duration of mean arterial pressure below 65 mmHg during anesthesia(Intraoperative period)
- Correlation between intraoperative hypotension duration and renal biomarker changes(Intraoperative period to postoperative 12-24 hours)
- Correlation between surgical field quality and intraoperative hypotension(End of surgery)