An observational study in Lumbar Stabilization Surgery and Noninvasive Hemoglobin Monitoring, sponsored by Sehit Prof. Dr. Ilhan Varank Sancaktepe Training and Research Hospital. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-16.
Sponsored by Sehit Prof. Dr. Ilhan Varank Sancaktepe Training and Research Hospital · Observational
This prospective observational study aims to evaluate whether the prone position affects the agreement between noninvasive hemoglobin (SpHb) measurements and laboratory hemoglobin values in patients undergoing lumbar stabilization surgery under general anesthesia.
SpHb provides continuous, noninvasive monitoring of hemoglobin using multi-wavelength pulse CO-oximetry. However, its accuracy may be affected by changes in peripheral perfusion, hemodynamic status, and patient position. The prone position used during spine surgery may alter cardiovascular function and peripheral perfusion and may therefore influence SpHb measurements.
In this study, SpHb values obtained in the supine and prone positions will be compared with simultaneously obtained laboratory hemoglobin values. The study will also evaluate the ability of SpHb to follow changes in hemoglobin during surgery. The results may help clarify the clinical usefulness of continuous noninvasive hemoglobin monitoring during surgery performed in the prone position.
This is a prospective, single-center observational study involving adult patients undergoing lumbar stabilization surgery under general anesthesia. Eligible patients will be older than 18 years and classified as American Society of Anesthesiologists (ASA) physical status I-III.
During surgery, noninvasive hemoglobin concentration (SpHb) will be monitored using a pulse CO-oximetry sensor placed on the finger as part of intraoperative monitoring. SpHb measurements will be compared with laboratory hemoglobin values obtained from blood gas analysis. Measurements obtained during supine and prone positioning will be evaluated to determine whether prone positioning affects the agreement between noninvasive and laboratory hemoglobin measurements.
Demographic and clinical characteristics, intraoperative hemodynamic variables, laboratory and blood gas parameters, estimated intraoperative blood loss, amount of transfused blood products, postoperative intensive care unit stay, and total hospital length of stay will also be recorded. The study will additionally assess the potential of SpHb for following intraoperative hemoglobin trends.
Adult patients undergoing elective lumbar stabilization surgery under general anesthesia at Sancaktepe Şehit Prof. Dr. İlhan Varank Training and Research Hospital. Eligible participants will have an ASA physical status of I-III and will undergo intraoperative noninvasive hemoglobin (SpHb) monitoring together with laboratory hemoglobin measurements.
Exclusion Criteria:
Adult patients undergoing lumbar stabilization surgery under general anesthesia. Noninvasive hemoglobin (SpHb) and laboratory hemoglobin measurements will be obtained and compared during supine and prone positioning.
Other: Prone Positioning
Prone positioning is performed as part of standard surgical care for lumbar stabilization surgery and is not assigned by the investigators. The study will evaluate the association between prone positioning and the agreement between noninvasive hemoglobin (SpHb) measurements and simultaneously obtained laboratory hemoglobin values.
Agreement Between Noninvasive Hemoglobin (SpHb) and Laboratory Hemoglobin Measurements
Paired noninvasive hemoglobin (SpHb) and laboratory hemoglobin values will be obtained at corresponding intraoperative time points in the supine and prone positions. The primary outcome is the agreement between SpHb and laboratory hemoglobin measurements and whether this agreement changes after positioning the patient prone.
Time frame: Intraoperative period, during supine and prone positioning on the day of surgery
Ability of SpHb to Track Intraoperative Hemoglobin Changes
Changes in noninvasive hemoglobin (SpHb) measurements over the intraoperative period will be compared with corresponding changes in laboratory hemoglobin values to evaluate the ability of SpHb to track the direction and magnitude of hemoglobin changes during surgery.
Time frame: Intraoperative period on the day of surgery
Plan to share: No
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Sehit Prof. Dr. Ilhan Varank Sancaktepe Training and Research Hospital