Preoperative Evaluation of IVC Collapsibility Index and Caval Aorta Index After Induction of General Anesthesia

Post- anesthesia hypotension is of common occurrence, and it hampers tissue perfusion. The magnitude of hypotension is determined by the preoperative volume status, which varies depending on American Society of Anesthesiologists (ASA) physical status, preoperative comorbidities, preoperative medications, and fasting.

General anesthesia causes significant alterations in hemodynamics, as both inhalational and intravenous anesthetics cause bradycardia, decrease in systemic vascular resistance and vasodilatation, and decrease in myocardial contractility, cardiac output and stroke volume, with the absence of surgical stimulus, making induction of anesthesia is the most crucial period at which hypotension occurs.

Due to different definitions of hypotension and diverse patient populations, the effect of volume preload on prevention of hypotension is still controversial. Many recommendations to identified sonographic determination of inferior vena cava (IVC) collapsibility index (IVCCI) as non-invasive, and easy technique for evaluating volume status. Recent guidelines from the American Society of Echocardiography support the general use of IVCCI in assessing volume status.

Inclusion criteria

• Age from 18 to 40 years.
• Both sexes.
• Body Mass Index< 40 kg/m².
• American Society of Anesthesiologists (ASA) physical status I, II.
• Fasted according to the ASA guidelines: 2 hours for clear fluids, 6 hours after light meal, 8 hours after a full meal with high calorie or fat content.
• Scheduled for elective craniotomy surgeries before induction of general anesthesia.

Exclusion criteria

• Current or recent pregnancy (within 3 months).
• Pre-existing cardiac disease or hypertension.
• On medications affecting blood pressure [Beta-blockers (BBs) and calcium channel blockers (CCBs)] .
• Refusing to undergo the study.