Comparative study to evaluate blood pressure levels measured by an invasive method versus a non-invasive method in patients in an intensive care unit

Introduction

The blood pressure is an important variable in medical practice. A mistaken measurement can change the management of some diseases, modifying the patient's prognosis. Therefore a correct definition and control of blood pressure is an essential item in an ICU environment.

Methods

A prospective and comparative study of the blood pressure assessed by arterial catheterization (pressure referenced to atmospheric pressure at mid-chest level and adequate curve in the monitor) and by non-invasive blood pressure device (using the cuff of the monitor with automatic oscillometric measurement) in the upper and lower limbs.

Results

Included were 52 patients with average age of 54.7 years. In the right arm (RA), a difference between IBP and NIBP larger than or equal to 20 mmHg in systolic blood pressure (SBP) (plus or minus) occurred in 26.5% of the patients; 14.3% in diastolic blood pressure (DBP) and 8.7% in mean blood pressure (MBP). In the left arm (LA), 30.6% for SBP; 4.1% for DBP and 4.2% for MBP. In the left leg (LL), 40% for SBP, 17.8% for DBP and 17.8% for MBP. In the right leg (RL), 47.8% for SBP; 8.7% for DBP and 17.4% for MBP.

Conclusions

There were differences between BP measured by invasive and non-invasive methods mainly in SBP. Lower limbs presented a larger difference, which means that non-invasive methods in this place are not reliable. The DBP in both methods presented less difference.