This retrospective medical record review was deemed exempt by the Institutional Review Board, Office of Research and Grants at Arrowhead Regional Medical Center. Records of patients admitted to our institutions with severe TBI who required intubation and admission to the ICU between January 20, 2009, and November 8, 2016 were reviewed. 

Patients were selected for this study if they had received a bowel regimen that consisted of scheduled daily doses of bisacodyl and docusate sodium, received nasogastric tube feeding within 24 hours of presentation, and received the same fluid management with a 0.9% saline solution and maintenance fluids based on the patient's body weight in kilograms. Patients were excluded if their records showed any blunt or penetrating trauma to the abdominal cavity, any injury to the spine or spinal cord, or any history of abdominal or pelvic surgery. We also excluded patients with known diabetes, because autonomic nerve function can be inhibited by diabetic autonomic neuropathy. The control group consisted of patients with TBI who were admitted to the ICU while intubated and who were unable to have a bowel movement within 48 hours of admission but who did not receive mesenteric lift. (Control group patients did not receive mesenteric lift because both allopathic and osteopathic neurosurgeons participated in the residency program in which this study occurred; during the days when allopathic neurosurgeons were on call, no OMT was performed.) Patients were intubated in the trauma unit before arriving in the ICU. The OMT technique was performed by attending osteopathic neurosurgeons (D.M.) and residents under direct supervision (J.A.D.B., J.O., S.K., and H.S.). The treatment and control groups received a full bowel regimen of medications to facilitate a bowel movement. 

Patients were positioned supine in their beds. The physician stood on the right side of the patient and bent the patient's knees. The physician's hands were placed on the abdominal wall on either side of the cecum wall in the right lower quadrant with the fingers medial to the anterior superior iliac spine. A gentle scooping motion was performed with the fingers that started in the region of the cecum in the right lower quadrant, then moved superior to the transverse colon, and then moved to the right across the midline. The physician performed a lifting motion after pressing deeper into the abdomen. A deep technique was used to mobilize the abdominal viscera. The technique then followed the colonic wall down the right side, toward the sigmoid. 

Seventy-nine patients (35 study, 44 control) met the inclusion criteria. Their ages ranged from 19 to 83 years (mean, 42 years), and the majority were men (men, 29 [66%]; women, 15 [34%]). The study group population ranged from age 17 to 69 years (mean, 39 years). There was also a slight male predominance (men, 24 [68%]; women, 11 [32%]). After receiving OMT, 27 of 35 patients (77%) had a bowel movement within 24 hours of completing treatment, compared with 16 of 44 (36%) control patients (P=.01). Patients who received mesenteric lift within the specified period in our study were 212% more likely to have a bowel movement compared with those who did not. 

Neurogenic bowel is a common occurrence in patients with TBI, with reported rates ranging from 30% to 60%.⁷ In severe TBI, a sympathetic surge shunts blood away from the mesenteric vessels of the GI tract and into the muscles. This disrupts the normal balance and regulation of sympathetic and parasympathetic discharge from the hypothalamus and the fibers, which both enter and leave this autonomic center. The celiac, superior mesenteric, and inferior mesenteric ganglia are the primary autonomic ganglia in the enteric nervous system. The enteric nervous system contains more cell bodies than the spinal cord and is almost exclusively controlled by autonomic influences both sympathetic and parasympathetic.⁸ 

The autonomic efferent motor neurons in the myenteric (Auerbach) and submucosal (Meissner) plexuses contain μ-, κ-, and δ-opioid receptors that are extremely sensitive to opioid agonists, which cause a decrease in motility, secretion, and sphincter function.⁹ ICU patients often receive medications that are necessary for their clinical management but which greatly affect the autonomic nervous system. This adverse effect is seen frequently with the use of vasopressors, which are often used in patients with TBI to maintain adequate systolic blood pressure, mean arterial pressure, and cerebral perfusion pressure. These medications also increase shunting of blood away from the mesenteric system and toward the muscles. Additionally, opiates play a significant role in reducing GI motility. These factors contribute to a decrease in GI motility that can interfere with fluid absorption and expel waste from the body. The inability to properly absorb fluids, nutrients, and medications due to decreased blood flow to the GI tract can be detrimental in patients with severe TBI. 

Although there are limited data documenting the efficacy of OMT in adult patients in the ICU, its use in a critical care setting is supported in the literature. Two studies,^10,11 in particular, have shown significant improvements in GI function in preterm neonates in the ICU that have resulted in reduced length of stay, increased weight gain, and reduced medical costs. The mesenteric lift technique can function as both a direct and indirect technique. As a direct technique, it manually promotes persistalsis in the GI tract and can potentially relieve mechanical obstructions by softening and mobilizing stool. Indirectly, it can be a form of myofascial release, releasing visceral restrictions.¹¹ 

Several limitations exist in this study that introduce potentially confounding variables. The retrospective nature inherently introduces a selection bias. Because of limitations with our institution's medical records system, it was difficult to analyze which patients in our treatment and control groups were receiving vasopressors and opiate drips and for what duration; these factors are confounding variables because they can play a role in the constipation rates in both patient groups. An additional limitation is that much of the medical history of the patients was unknown, as trauma patients often do not have any identifying information for several days. 

This increase in GI motility shown in our study resulting from mesenteric lift improves the absorption of nutrients, medications, and fluids, which can improve clinical outcomes. While this study focused on a very specialized patient population, we believe that OMT can be applied to a broader population to optimize the functioning of the GI system. 

All authors provided substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; all authors drafted the article or revised it critically for important intellectual content; all authors gave final approval of the version of the article to be published; and all authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.