Effect of the transversus abdominis plane block on the postoperative course of cesarean section in women with preeclampsia: a single-center, prospective, randomized study

BACKGROUND: In women with preeclampsia, the need for continuation of antihypertensive therapy after abdominal delivery persists. Postoperative pain may contribute to the set of factors underlying hypertension. The effect of the transversus abdominis plane (TAP) block on the course of hypertension in women with preeclampsia after cesarean section remains insufficiently studied.

AIM: This study aimed to comparatively evaluate pain intensity, hemodynamic parameters, and the requirement for analgesic and antihypertensive therapy in women with preeclampsia during the first 24 hours after cesarean section under multimodal analgesia alone and multimodal analgesia supplemented with TAP block.

METHODS: Women with preeclampsia (n = 104) were randomized into two groups. Group 1 (n = 54) received multimodal analgesia; group 2 (n = 50) received multimodal analgesia combined with TAP block. The study included assessment of pain intensity using the visual analog scale, blood pressure, and heart rate before surgery and at 3, 6, 12, and 24 hours postoperatively. Blood glucose and serum cortisol concentrations were measured preoperatively and at 12 and 24 hours after surgery. Cardiac index and total peripheral vascular resistance were evaluated before surgery and at 24 hours postoperatively. Analgesic load and antihypertensive therapy were analyzed and compared between groups 24 hours after surgery.

RESULTS: During the first postoperative day, visual analog scale pain scores, as well as blood glucose and cortisol concentrations, were significantly higher in group 1 compared with group 2. The frequency of trimeperidine administration in group 1 was increased twofold (p = 0.000), and tramadol administration increased 45.5-fold (p = 0.000). Antihypertensive therapy was modified as follows: to correct hypotension in 13.0% of patients in group 1 and 46.0% in group 2 (p = 0.002); to correct hypertension in 46.3% and 16.0% of patients, respectively (p = 0.006). These adjustments allowed maintaining target arterial blood pressure values in groups. Cardiac output and total peripheral vascular resistance did not differ between groups before and after surgery. No adverse reactions associated with TAP block were observed.

CONCLUSIONS: TAP block provided lower postoperative pain intensity and reduced opioid consumption in women with preeclampsia after cesarean section. Improved analgesic efficacy reduced the incidence of progression of hypertension by 2.4-fold and increased the number of patients showing a tendency toward resolution of hypertension by 3.5-fold during the first postoperative day. Adjustment of antihypertensive therapy under TAP block conditions had no negative effect on cardiac output or total peripheral vascular resistance. The study is limited by its single-center design and by the inability to exclude the influence of the visceral pain component on hypertension.