Description

Following the onset of general anesthesia, hypotension is frequently observed, and intraoperative hypotension is linked to end organ damage following surgery, including cardiac ischemia and severe renal injury. postoperative end-organ damage depends on the duration and magnitude.

The incidence of hypotension after induction of general anesthesia varies and is influenced by the induction agent, patient characteristics, and the definition of hypotension.

Hypotension was defined by a 30% reduction in the SBP or 20% reduction in the MAP from baseline or an absolute SBP of less than 90 mm Hg and MAP of less than 65 mm Hg within 3 minutes after induction of general anesthesia.

Elderly people are more likely to experience hemodynamic fluctuation and hypotension due to the high prevalence of left ventricular diastolic failure, lower vascular reactivity and higher sensitivity to anesthetics. More significantly, older patients can't tolerate hypotension for a long time.

A variety of hemodynamic monitoring techniques have been used to predict post- anesthetic hypotension. Non-invasive cardiometry, ultrasound evaluation of fluid status, and pulse oximetry variables, such as the perfusion index and pulse variability index, were utilized.

Zhang and Critchley demonstrated that preoperative hypovolemia predicted postinduction hypotension as determined by the inferior vena cava (IVC) diameter and IVC collapsibility index.

In many clinical situations, volume-responsive patients have been identified using Doppler-derived metrics such as the peak blood flow peak velocity variation (ðVpeak) and the common carotid artery corrected flow time (cFT).

The carotid artery Doppler measures provide several benefits, including being noninvasive and being technically simple to obtain due to the carotid artery's superficial nature. Since the common carotid artery cFT is unaffected by respiratory attempts, it can also be used to assess a patient's volume responsiveness when they are breathing on their own.