Eg. Pivalizza et al., PERIOPERATIVE THROMBOELASTOGRAPHY AND SONOCLOT ANALYSIS IN MORBIDLY OBESE PATIENTS, Canadian journal of anaesthesia, 44(9), 1997, pp. 942-945
Purpose: To investigate perioperative coagulation in morbidly obese (M
O) patients with the thromboelastography (TEG) and Sonoclot analyzer.
Methods: Twenty-six consecutive morbidly obese and 26 consecutive lean
patient presenting for elective surgery were enrolled in this prospec
tive observational study. Blood was sampled for and Sonoclot analysis
immediately after anaesthetic induction and at the end of surgery in t
he MO group, and immediately after anaesthetic induction in the lean g
roup. The R and K times, alpha angle, maximum amplitude and percentage
fibrinolysis at 30 and 60 min were recorded from the TEG. The Sonoclo
t ACT, initial clot rate, peak amplitude and time to peak amplitude we
re recorded from the Sonoclot. Results: The TEG in the MO group demons
trated decreased R and K times (8.6 +/- 4.8 vs 11.7 +/- 3.9 mm, and 2.
8 +/- 1.2 vs 3.5 +/- 0.9 mm respectively (P < 0.05)), and increased al
pha angle (73.7 +/- 6.0 vs 66.7 +/- 6.0 degrees, P < 0.05) and maximum
amplitude (72.0 +/- 5.4 vs 67.9 +/- 4.4 mm, P < 0.05), without change
in fibrinolysis, Sonoclot variables in the MO group included increase
d clot rate (37.5 +/- 11.5 vs 23.9 +/- 7.7%, P < 0.05) and decreased t
ime to peak impedance (11.7 +/- 5.0 vs 17.5 +/- 7.2 min, P < 0.05, wit
hout change in Sonoclot ACT or peak signature impedance. Conclusion: T
he MO group demonstrated accelerated fibrin formation, fibrinogen plat
elet interaction, and platelet function compared with lean controls bu
t no difference in fibrinolysis, Viscoelastic measures of coagulation
may be useful in MO patients, who are are at increased risk of thrombo
embolic events.