Comparison of indirect and direct blood pressure monitoring in normotensive swine.

The gold standard for blood pressure measurement in pigs is direct monitoring of arterial pressure, but this is an invasive technique adding complexity to surgical procedures. We sought to compare direct measurements obtained via catheterization to more easily-obtained indirect measurements using a sphygmomanometer with an automated cuff. Simultaneous measurements via an arterial pressure transducer and a child-size cuff were performed in pigs undergoing abdominal surgical procedures under normotensive conditions. Correlation between direct and indirect measurements was good (r=0.881). Systolic blood pressures for the cuff were higher than those for arterial measurements, while diastolic pressures were lower for the cuff than arterial. A Bland-Altman analysis confirmed this bias at the extremes of the normotensive range. For highly accurate readings, especially under stressed conditions, direct arterial catheterization remains the preferred method of measuring blood pressure. When monitoring surgical procedures, the more convenient blood pressure cuff can provide reliable measurements.