[Effects of treatment based on different target mean arterial pressure on gastrointestinal function in septic shock patients with hypertension].

OBJECTIVE

To investigate the effect of fluid resuscitation and circulatory support, directed by different target mean arterial pressure (MAP), on abdominal blood flow, gastrointestinal function and inflammatory response in septic shock patients with hypertension.

METHODS

A prospective randomized controlled study was conducted. Hypertensive patients with septic shock admitted to the department of intensive care unit (ICU) of Liuzhou People's Hospital from January 1, 2019 to May 31, 2020 were enrolled. Patients were randomly divided into the low MAP groups (low standard group, LS group) or high MAP group (high standard group, HS group). According to the Surviving Sepsis Campaign Guidelines in 2016 and the updated guideline in 2018, all patients were given treatment of primary disease, fluid resuscitation, supportive management. The target MAP was 65-70 mmHg (1 mmHg = 0.133 kPa) in LS group, and was 75-80 mmHg in HS group. Acute gastrointestinal function injury (AGI) classification was performed on the 1st, 3rd and 7th day. The mean flow rate (Vm) and resistance index (RI) of superior mesenteric artery were evaluated using ultrasound, and the gastrointestinal function was dynamically evaluated using the modified single section ultrasonic gastric antrum method. The gastric antrum movement index (MI) and gastric empaging time (GET) were recorded. The levels of inflammatory markers in serum were detected by enzyme linked immunosorbent assay (ELISA), such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), procalcitonin (PCT) and vascular endothelial growth factor (VEGF). The target MAP, the days of use of vasopressors and the amount of fluid resuscitation were recorded.

RESULTS

A total of 208 hypertensive patients with septic shock were enrolled, including 109 in the LS group and 99 in the HS group. There were no significant differences in gender, age, acute physiology and chronic health evaluation II (APACHE II) score and sequential organ failure assessment (SOFA) score between the two groups when diagnosed. After treatment, there was no significant difference in AGI classification between the LS group and HS group on the 1st day. On the 3rd and 7th day, there were statistical differences between the two groups (3rd day: proportion of I, II, III, IV grades were 25.69%, 56.88%, 11.93%, 5.50% in LS group, 15.15%, 54.55%, 25.25%, 5.05% in HS group, respectively, χ = 7.900, P = 0.048; 7rd day: proportion of I, II, III, IV grades were 44.96%, 49.54%, 3.67%, 1.83% in LS group, 31.31%, 52.53%, 11.11%, 5.05% in HS group, respectively, χ = 8.178, P = 0.042). The Vm of superior mesenteric artery was higher and the RI was lower in the LS group than those in the HS group on day 1, 3 and 7 [Vm (cm/s): 21.72±3.02 vs. 19.50±2.83, 20.42±2.62 vs. 17.02±1.99, 26.52±2.70 vs. 22.47±4.03; RI: 0.86±0.05 vs. 0.92±0.04, 0.87±0.05 vs. 0.95±0.05, 0.81±0.03 vs. 0.85±0.03, all P < 0.01]. The MI was higher and the GET was shorter in the LS group than those in the HS group on day 3 and day 7 [MI: 3.00±0.33 vs. 2.60±0.29, 4.50±0.51 vs. 3.90±0.33; GET (minutes): 86.01±19.78 vs. 100.99±25.01, 71.00±16.37 vs. 84.98±20.18, all P < 0.01]. In addition, the levels of serum TNF-α, IL-6, PCT, VEGF were lower in the LS group than those in the HS group after 3 days of treatment [TNF-α (ng/L): 147.05±28.32 vs. 256.99±27.04, IL-6 (ng/L): 762.99±57.83 vs. 1 112.30±118.32, PCT (μg/L): 37.00±5.58 vs. 56.00±12.36, VEGF (ng/L): 123.00±19.78 vs. 167.01±21.55, all P < 0.05]. The target MAP was maintained at (68.02±4.71) mmHg in LS group, and (79.04±3.04) mmHg in HS group. The difference between the two groups was statistically significant (P < 0.01). Compared with the HS group, the days of using vasopressors was shorter in LS group (days: 3.50±1.27 vs. 4.55±1.47), and the amountof fluid was reduced significantly (mL: 1 602.29±275.49 vs. 2 000.30±272.59, both P < 0.01).

CONCLUSIONS

Maintaining a low target mean arterial pressure (65-70 mmHg) in hypertensive patients with septic shock can improve blood supply of superior mesenteric artery, protect the gastrointestinal function, reduce the level of inflammatory factors, and diminish the duration of using vasopressors and the amount of fluid.