Inferior Vena Cava Ultrasonography before General Anesthesia Can Predict Hypotension after Induction

Abstract

Background Hypotension is a common side effect of general anesthesia induction, and when severe, it is related to adverse outcomes. Ultrasonography of inferior vena cava (IVC) is a reliable indicator of intravascular volume status. This study investigated whether preoperative ultrasound IVC measurements could predict hypotension after induction of anesthesia. Methods One hundred four adult patients, conforming to American Society of Anesthesiologists physical status I to III, scheduled for elective surgery after general anesthesia were recruited. Maximum IVC diameter (dIVCmax) and collapsibility index (CI) were measured preoperatively. Before induction, mean blood pressure (MBP) was recorded. After induction, MBP was recorded for 10 min after intubation. Hypotension was defined as greater than 30% decrease in MBP from baseline or MBP less than 60 mmHg. Receiver operating characteristic curve analysis with gray zone approach and regression analyses were used. Results IVC scanning was unsuccessful in 13.5% of patients. Data from 90 patients were analyzed. After induction, 42 patients developed hypotension. Areas (95% confidence interval) under the curves were 0.90 (0.82 to 0.95) for CI and 0.76 (0.66 to 0.84) for dIVCmax. The optimal cutoff values were 43% for CI and 1.8 cm for dIVCmax. The gray zone for CI was 38 to 43% and included 12% of patients and that for dIVCmax was 1.5 to 2.1 cm and included 59% of patients. After adjusting for other factors, it was found that CI was an independent predictor of hypotension with the odds ratio of 1.17 (1.09 to 1.26). CI was also positively associated with a percentage decrease in MBP (regression coefficient = 0.27). Conclusions Preoperative ultrasound IVC CI measurement was a reliable predictor of hypotension after induction of general anesthesia, wherein CI greater than 43% was the threshold.

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“…In 2016, Zhang and Critchley reported that the IVC collapsibility index was a reliable predictor of postinduction hypotension in Chinese patients undergoing elective surgery. As the IVC collapsibility index is a known predictor of volume responsiveness in spontaneously breathing patients in various settings, it may be postulated that hypovolemia contributed to the postinduction hypotension.…”

Transesophageal Echocardiographic Measurements of the Superior Vena Cava for Predicting Fluid Responsiveness in Patients Undergoing Invasive Positive Pressure Ventilation

“…Zhang et al found that the IVC diameter was lower in hospital patients than in healthy volunteers. Other investigators have found that preoperative ultrasound measurements of the IVC with a CI of less than 43% was an effective predictor of hypotension after general anesthesia induction, and it could prevent patients from high‐risk complications resulting from intraoperative hypovolemia and hypotension . However, mechanical ventilation, obesity, accumulation of gas in the gastrointestinal tract, abdominal injury, edema, and other factors may incur difficulties in accurately measuring the IVC diameter .…”

Focused Cardiac Ultrasound for the Regional Anesthesiologist and Pain Specialist

“…4B) Under normal circumstances, the IVC is collapsible with spontaneous inspiration and should not be mistaken for the aorta, which is pulsatile and noncollapsible. The IVC diameter and collapsibility give insight into the patient's volume status, the potential for hypotension upon induction, 21 and fluid bolus responsiveness.…”