Preoperative Neutrophil-to-Albumin Ratio and Post-Induction Hemodynamic Vulnerability in Major Oncologic Surgery

This is a prospective, observational, non-interventional study involving adult patients undergoing elective major oncologic surgery under general anesthesia. The study is designed to evaluate the relationship between the preoperative neutrophil percentage-to-albumin ratio (NPAR) and post-induction hemodynamic vulnerability.

A total of 220 patients are planned to be enrolled using consecutive sampling. Eligible participants will be adults aged 18 years or older who are scheduled for elective major oncologic surgery under general anesthesia, have available preoperative complete blood count and serum albumin measurements, and undergo standard hemodynamic monitoring.

NPAR will be calculated by dividing the preoperative neutrophil percentage by the serum albumin concentration in g/dL. Demographic characteristics, ASA physical status, comorbidities, preoperative laboratory values, baseline hemodynamic measurements, induction-related data, intraoperative fluid administration, and vasopressor use and doses will be recorded prospectively.

Hemodynamic measurements will be evaluated from induction of general anesthesia until surgical incision, with a maximum observation period of 20 minutes. Participants will be classified according to the presence or absence of post-induction hemodynamic vulnerability.

The study will not alter routine anesthetic or surgical management. No additional medication, laboratory test, invasive procedure, or treatment modification will be performed for research purposes. Anesthetic agents, fluid therapy, and vasopressor administration will be determined by the responsible anesthesia team according to routine clinical practice.

The predictive performance of NPAR will be evaluated using receiver operating characteristic curve analysis and the area under the curve. Multivariable logistic regression analysis will be used to examine the association between NPAR and post-induction hemodynamic vulnerability while accounting for relevant clinical variables.

Inclusion criteria

• Age 18 years or older
• Scheduled for elective major oncologic surgery
• Undergoing surgery under general anesthesia
• Availability of preoperative complete blood count and serum albumin -measurements
• Standard hemodynamic monitoring
• Provision of written informed consent for participation in the study

Exclusion criteria

• Age younger than 18 years
• Emergency surgery
• Preoperative hemodynamic instability
• Preoperative vasopressor or inotropic support
• Sepsis or active infection
• Hematologic malignancy
• Advanced cardiac, renal, or hepatic failure
• Pregnancy
• Missing preoperative laboratory data -Inability to complete the 20-minute post-induction evaluation period-