Relationship of Preoperative inferior vena cava diameter and general anesthesia-associated hypotension

The surgical results are negatively impacted by intraoperative hypotension. An key risk factor for intraoperative hypotension is hypovolemia. The intravascular volume status and anaesthesia-associated hypotension are now increasingly determined by preoperative inferior vena cava diameter (dIVC) and collapsibility index (IVCCI) measurements .

A study that was recently released examines the relationship between the preoperative diameter of the inferior vena cava (IVC) during spontaneous breathing (dIVCmax) and the IVCCI and general anesthesia-related hypotension (GAAH).

The research comprised 110 adult patients who were having elective surgery under general anesthesia. Twenty to thirty minutes before the patient was transferred to the operation room, IVC ultrasonography was performed in the preoperative room. Two minutes and ten minutes after giving vecuronium, hypotension was seen (hypo@). There were 107 patients analyzed. Patient height and dIVCmax had a strong positive connection (r = 0.25, P = 0.009). For predicting hypo@2 min, the area under the receiver operating characteristic curve for dIVCmax and IVCCI was 0.595 (95% confidence interval (CI) 0.485-0.705) and 0.568 (95% CI 0.458-0.679), respectively, with diagnostic accuracy of 54% and 53%. In terms of predicting GAAH, dIVCmax 1.14 cm exhibited a sensitivity of 31% and a specificity of 87%. IVCCI 63.3% had an 84% specificity and 31% sensitivity for predicting GAAH. Preoperative fasting or environmental variables did not significantly affect the preoperative IVC values. IVCCI was computed using the formula IVCCI = dIVCmax - dIVCmin/dIVCmax 100 and represented as a percentage. The vein's diameter was measured during inspiration (dIVC min) and expiration (dIVC max) during a single respiratory cycle.

Patient height and dIVCmax were shown to be significantly correlated in the current research (r = 0.25, P = 0.009). Previous investigations have shown a similar positive connection between height and dIVCmax diameters.

In the current investigation, a statistically significant association between patient height and dIVCmax was found. Fasting duration and preoperative IVC measures did not significantly correlate with one another (dIVCmax, IVCCI). The diagnostic performance of fasting length in predicting GAAH [measured at 2 minutes after induction of anaesthesia] was equally subpar.

Long-term preoperative fasting may cause a hidden fluid deficit that is difficult for young, healthy people to identify. Nevertheless, individuals who are old, have co-morbid conditions, or are undergoing high-risk operations may exhibit this deficiency in a clinically significant way. The current research is unique in a number of ways. It assessed the relationship between preoperative IVC values, extended fasting states, and ambient humidity and temperature. Also noted is the prospective significance of "Visible IVC collapse" in forecasting GAAH.

Preoperative fasting, GAAH, ambient temperature, and humidity did not significantly correlate with the preoperative ultrasound-guided assessment of dIVCmax and IVCCI. In terms of predicting GAAH, both dIVCmax and IVCCI demonstrated poor diagnostic accuracy, excellent specificity, and low sensitivity. It is necessary to create a consistent formula for IVC diameter prediction that is modified for patient demographics.

Reference-

Agarwal, Jyotsna; Panjiar, Pratibha; Khanuja, Samiksha; Annapureddy, Sai Krishna R.; Saloda, Ali; Butt, Kharat M.. Correlation of preoperative inferior vena cava diameter and inferior vena cava collapsibility index with preoperative fasting status, patient demography and general anaesthesia associated hypotension: A prospective, observational study. Indian Journal of Anaesthesia: October 2022 - Volume 66 - Issue Suppl 6 - p S320-S327.doi: 10.4103/ija.ija_354_22