New Methods to Detect a Decrease in Heart Function

The incidence of hypotension during onset of spinal anesthesia in elderly patients varies from 27% to 80% depending on which definition being used. Studies of cardiac output (CO) has shown that it is maintained or only slightly decreased .

Unfortunately, the time-resolution in these studies is often several minutes, and the description of changes is consequently often a start-to-end relation rather than a description of the dynamic changes during onset of spinal anesthesia.

A recent advance in measuring CO is the LiDCOTMplus hemodynamic monitor, which has proved reliable compared to pulmonary artery catheters in various intensive care settings. This monitor allows for beat-to-beat measuring during various procedures and thus early warning of hemodynamic events.

Another method with potential for early warning of decreased perfusion is near-infrared spectroscopy (NIRS). NIRS is used for continuous and non-invasive monitoring of cerebral oxygen saturation (ScO2) and even a small reduction has recently shown to predict maternal hypotension during caesarian section.

The aim of our study was to describe the changes in CO during onset of spinal anesthesia in elderly patients using a method with high time-resolution. We also attempted to evaluate NIRS as predictor of hemodynamic events.

Inclusion criteria

• Age 60 years or older
• Elective orthopedic or plastic lower limp surgery
• in spinal anesthesia

Exclusion criteria

• Body weight <40 kg
• Currently in treatment with lithium
• Evidence of aortic valve regurgitation