6% Hydroxy ethyl starch versus 0.9% sodium chloride preloading during spinal anesthesia for elective cesarean delivery : coagulation changes using thromboelastography

الملخص EN

The aim of this study was to evaluate and compare the effects of fluid preloading with 6% hydroxyethyl starch (HES) (130 / 0.4) and 0.9 Sodium Chloride (Normal Saline) solutions on blood coagulability using thromboelastography (TEG) in healthy pregnant patients prior to spinal anesthesia for Cesarean delivery.

Methods: 30 healthy parturients (ASA physical status I) with uncomplicated singleton pregnancies at full term presenting for elective cesarean delivery under spinal anesthesia (intrathecal) were randomly allocated to one of two study groups, prior to spinal anesthesia.

HES-Group (n=15): receive fluid preloading with 500 mL 6% Hydroxy-Ethyl-Starch (VOLUVEN® 6% hydroxyethyl starch 130/0.4).

NS-Group (n=15): receive fluid preloading with 1500 mL 0.9% sodium chloride (Normal Saline).

Parturients with significant medical or obstetric co¬morbidity including hypertension, preeclampsia, liver disease, preexisting coagulation disorders were excluded.

Standard Thromboelastography (TEG) parameters were analyzed before and after fluid preloading in each group, in terms of the reaction time (r) in minutes, the k time (min), the alpha angle (degree) and the maximum amplitude (MA) (mm).

Results: The preoperative hematological investigations, for all parturients, including prothrombin time (PT), partial thromboplastin time (PTT), international normalized ratio (INR), fibrinogen level, hemoglobin level and platelet counts were similar and within normal values and this exclude preexisting coagulation disorders.

All these values showed insignificant differences between the two groups (P < 0.05).

Before fluid preloading; the baseline thromboelastograph parameters, in both groups (HES and NS), were in the normal range associated with normal pregnancy and there were statistically insignificant differences among the two groups (p>0.05).

After fluid preloading; in HES-group although, these parameters remained within the normal reference range, the r time (6.85±0.6 min) and k-times (2.28±2.3 min) were significantly longer when compared to baseline values (P= 0.01 for r-time andp = 0.04 for k-time), while the alpha angle (60.69±4.60C) and MA (57.8±2.6 mm) were significantly lower when compared to baseline values (p = 0.05 for a-angle andp = 0.04 for MA).In the NS group no significant differences were seen in all thromboelastograph (TEG) values when compared to baseline values (p>0.05).

Conclusion: Compared with 0.9% Sodium Chloride, 6% hydroxyethylstarch 130 / 0.4 are more likely to produce coagulation abnormalities in the form of mild hypocoagulable effect by thromboelastogram (TEG) in healthy parturients undergoing elective cesarean delivery, but these TEG parameters following the HES preload remained within the normal reference range for normal pregnancy so; they may not be associated with adverse patient outcomes.