During the aging process, many important changes occur in the cardiovascular system. In
elderly patients undergoing surgery, systemic vascular resistance is generally high but
accompanying dehydration is a very common condition. The hemodynamic status of these patients
may be compromised during spinal anesthesia due to the decrease in both systemic vascular
resistance (SVR) and cardiac preload. Intraoperative hypotension may develop after spinal
anesthesia. Intraoperative hypotension can prolong hospital stay by causing serious
complications, and it can significantly affect mortality rates. Predicting hypotension which
may develop after spinal anesthesia, can save time to decide, prepare and apply preventive
interventions.
Shock index (SI) has been defined as the ratio of heart rate (HR) to systolic blood pressure
(SBP). SI is an easy and non-invasive marker used in hypovolemia and early diagnosis of
shock. SI is usually <0.7. In case of acute hypovolemia and circulatory failure, this ratio
increases. It has been stated that in critical patients, diastolic blood pressure (DBP) will
drop earlier than SBP, and the mean blood pressure will be a more accurate marker to assess
the severity of the disease. For this reason, the modified shock index (MSI), which is
obtained by dividing the heart rate by the mean arterial pressure (MAP), has been defined.
MSI> 1.3 indicates a hypodynamic state.
The Age Shock Index (ASI) is defined by multiplying SI by age. In trauma patients, this index
has been shown to correlate with a higher mortality rate with an increase greater than 50.
Since age affects the physiological reserve negatively, it has been stated that ASI is a
better predictor of 48-hour mortality compared to heart rate, SBP or SI. In studies
evaluating ASI, SI and MSI to predict post-intubation hypotension; pre-intubation SI, MSI,
ASI values have been shown to be the independent predictors of post-intubation hypotension.
Aim of this prospective observational study is to investigate whether SI, MSI and ASI have
any predictive value in predicting post-spinal hypotension which may develop in patients over
65 years of age, who are planned to undergo transurethral resection of the prostate (TURP)
and transurethral resection of the bladder (TURB) surgery under spinal anesthesia.
The secondary objective is to compare the two groups in terms of preoperative and
postoperative blood tests, and to determine whether the patients were admitted to intensive
care or postanesthesia care unit. If the patient was admitted, length of unit and hospital
stay and postoperative complications (if developed any) will be recorded. In addition, the
investigators will examine whether intraoperative hypotension has any negative effects.
