The Annals of Thoracic Surgery, Vol 38, 117-123, Copyright © 1984 by The Society of Thoracic Surgeons
Sonomicrometry: its application as a routine monitoring technique in cardiac surgery
WY Moores, MM LeWinter, WB Long, M Grover, R Mack and PO Daily
We utilized ultrasonic-dimension crystals in approximately 50 patients
during a three-year period to evaluate clinical sonomicrometry as a routine
monitoring tool in patients undergoing cardiac operations. Standard
research piezoelectric pulse transit ultrasonic transducers were modified
with a hooked attachment in a tethered configuration to facilitate accurate
alignment and quick insertion for the measurement of myocardial segment
length changes. These segment crystals were used both intraoperatively and
postoperatively to evaluate the left ventricular pressure-geometry
relationships and to serve as a continuous monitor of myocardial function.
The left ventricular pressure-volume relationship was varied by temporarily
reapproximating the pericardium (pericardial closure resulted in a 12%
reduction in fractional shortening, a 5% decrease in end-diastolic segment
length, and an 8% increase in pulmonary artery diastolic pressure). During
both the intraoperative and postoperative periods, we found good
correlation between thermodilution, stroke volume, and myocardial
dimensions; no correlation was noted between pulmonary artery diastolic
pressure and stroke volume. No bleeding or major complications resulted
from the use of these sonomicrometry transducers. Our initial clinical
experience with sonomicrometry seems to support its use as a potentially
valuable monitoring tool.
