Background: Mannitol and hypertonic saline (HS) are routinely used during craniotomy. Both increase myocardial preload and reduce afterload, and may improve cardiac output. It is not currently known whether this results in an improvement in the global myocardial function. Thus, the aim of this study was to compare the effects of a single equiosmolar bolus of 20% mannitol (5 mL/kg) or 3% HS (5 mL/kg) on the global myocardial function by tissue Doppler-derived myocardial performance index (TD-MPI) in patients undergoing craniotomy.
Methods: Fifty adult patients were included and randomized to receive either mannitol or 3% HS. Transesophageal echocardiography was performed in all patients. Early (E) and late (A) peak mitral inflow velocity, early diastolic mitral annular velocity (E prime), isovolumetric relaxation time (IVRT), ejection time (ET), and isovolumetric contraction time (IVCT) were recorded at baseline and at 15, 30, 60, and 120 minutes after administration of the hyperosmolar solutions. TD-MPI was calculated as IVRT+IVCT/ET.
Results: There were no significant differences in the TD-MPI (HS vs. mannitol: 0.43 vs. 0.44 [baseline], 0.45 vs. 0.43 [15 min], 0.44 vs. 0.45 [30 min], 0.47 vs. 0.45 [60 min], 0.45 vs. 0.46 [120 min]), E/A ratio, IVCT, and E/E' either within or between the 2 groups at any time point. IVRT was prolonged in HS group as compared with baseline at 15, 30, and 60 minutes postinfusion. ET was decreased in both the groups at 120 minutes postinfusion. Neither of these altered the TD-MPI.
Conclusions: Equiosmolar administration of 20% mannitol and 3% HS did not show any difference in global myocardial performance as measured by TD MPI.