A complicated postoperative period developed in 7% of patients with SRT. Two thirds of this neurocritical care population has IAH, which developed on the second postoperative day. IAH correlated with worse APACHE-II and SOFA scores, and it occurred more frequently in non-survivors. Patients with normal IAP had better outcomes. However, the cause-and-effect relationship between IAP and severity of the patients' condition remains unclear. Severe injury to the hypothalamo-pituitary axis can lead to MOD . On the other hand, our patients had high maximal IAP values, and IAH can also be considered as a cause of MOD [5, 12]. Our data show the importance of IAP monitoring in these neurocritical care patients since early recognition and timely medical management can affect outcome.
Ileus was a leading cause of IAH in our cohort. Theoretically, capillary leak syndrome and fluid accumulation can also cause IAH [1, 3, 5]. This syndrome can be due to decompensated hypothyroidism  in patients with SRT and can lead to polyserositis with ascites, hydrothorax, and/or hydropericardium [6, 14]. In our population, severe hypothyroidism was ruled out because all the patients received postoperative polyhormonal therapy, and the levels of thyroid hormones in plasma were routinely controlled. Also, there were no patients with ascites in our study population.
Different types of ileus were observed: impaired intestinal and colonic emptying and a combined form. The leading cause of ileus was DD, and this can be explained by the surgery site. Hypothalamic nuclei directly regulate gastrointestinal motility [7, 15]. Furthermore, a normal thyroid status is necessary for an adequate function of the gastrointestinal tract . Independent risk factors had minor importance for the ileus development in our patients, especially narcotics, sympathomimetics, or positive fluid balance. The last is insignificant for SRT patients because central diabetes insipidus is a common postoperative complication. Sepsis was an important risk factor for ACS. Our results are in concordance with previous literature data [16–18]. Hypokalemia and hypomagnesaemia developed frequently due to glucocorticoid therapy .
Conservative treatment was effective in the majority of patients with IAH, but without ACS. In ACS, on the other hand, conservative treatment was ineffective in two thirds of the patients. Guidelines recommend urgent laparotomy if conservative therapy fails [5, 8, 20]. There are no publications on the timing and efficacy of urgent laparotomy in patients with secondary ACS due to neurosurgical pathology. Thoracic EA, used before laparotomy, should therefore be considered as a safe and effective therapeutic option.
The use of EA is generally accepted in the ICU and has been previously described [10, 21, 22]. The pathophysiological basis of thoracic EA for the treatment of ACS is: (1) sympathetic block and accordingly, prevalence of parasympathetic tonus in the innervation of the gastrointestinal tract, (2) strong analgetic effect, (3) abdominal wall muscle relaxation, (4) increase of gastrointestinal blood flow, gastric mucosal perfusion, improvement of tissue oxygenation, and (5) prevention of bacterial translocation [22–25]. These mechanisms can interrupt the deleterious pathological processes caused by ACS. We showed that the use of EA can be effective in a selected group of patients. In these patients, the IAP normalized within several hours, and signs of MOD regressed within 1 to 2 days. The duration of IAH in patients with EA was significantly shorter than that in patients without EA. We could not perform EA in two septic patients with ineffective conservative treatment for ACS. Traditionally, sepsis is a contraindication for EA due to an increased risk of infectious complications [21, 26]. All patients with ACS, who did not receive EA, died, irrespective of the duration of ACS. These data allow us to conclude the following: (1) early thoracic EA can be an effective treatment option for secondary ACS in neurosurgical patients; and (2) if the main cause of ACS in neurosurgical patients is sepsis, the only effective method of ACS treatment would probably be urgent laparotomy.
To our knowledge, this is the first study to investigate secondary ACS in patients with SRT. Our study has several serious limitations. First, 41 patients are still a small number for a meaningful statistical analysis, especially concerning the calculation of the risk of unfavorable outcomes and death in patients with IAH. Second, it is a single-center study. Third, we only performed intermittent measurements of IAP, not continuous monitoring, which could have changed the therapeutic approach and accordingly, the results. Fourth, four patients with EA are a small number for decision-making about the significance of EA for ACS treatment.