What are the possible causes of sudden abdominal distention in a patient with a cervical spine fracture, tracheostomy, and ventilation on BiPAP (Bilevel Positive Airway Pressure), who is hemodynamically stable and taking oral feeds?

Sudden Abdominal Distention in Cervical Spine Fracture Patient on BiPAP

In a tracheostomized, ventilated cervical spine fracture patient who develops sudden abdominal distention, the most likely causes are gastric distention from positive pressure ventilation, paralytic ileus from spinal shock, aspiration with gastric stasis, or acute gastric dilatation—all of which are significantly elevated risks in this specific population.

Primary Mechanisms Related to Cervical Spine Injury

Spinal Shock and Autonomic Dysfunction

• Paralytic ileus is a direct consequence of spinal shock in cervical spine injuries, particularly with upper cervical lesions, resulting from loss of sympathetic innervation to the gastrointestinal tract 1, 2.
• The autonomic dysfunction causes gastrostasis and impaired bowel motility, leading to progressive abdominal distention 1.
• This complication typically manifests within the first week after injury and can persist throughout the acute phase 2.

Gastric Distention from Positive Pressure Ventilation

• BiPAP ventilation significantly increases the risk of gastric distention through inadvertent air insufflation into the stomach, especially in patients with reduced lower esophageal sphincter tone from spinal shock 1.
• The combination of positive airway pressure and supine positioning promotes gastric stasis, reflux, and air swallowing 1.
• This risk is compounded in cervical spine injury patients who cannot be positioned optimally due to spinal precautions 1.

Aspiration and Pneumonia-Related Complications

• Gastrostasis, reflux, and aspiration are promoted by the static supine position required for cervical spine immobilization, leading to ventilator-associated pneumonia and prolonged complications 1.
• The inability to clear secretions effectively due to expiratory muscle weakness at C5 and above further compounds this risk 3.
• Poor oral care and prolonged immobilization are linked to bacteremia and sepsis, which can manifest with abdominal distention 1.

Ventilation-Specific Complications

BiPAP-Related Issues

• High-flow positive pressure can cause aerophagia and progressive gastric distention, particularly problematic in patients who cannot protect their airway adequately despite tracheostomy 1.
• The tracheostomy itself does not eliminate the risk of gastric distention from positive pressure ventilation 1.

Nutritional Complications

• Higher rates of failed enteral nutrition occur in immobilized cervical spine patients, with failure to reach nutritional targets potentially requiring parenteral nutrition 1.
• Enteral feeding in the setting of gastric stasis can lead to acute gastric dilatation and distention 1.

Critical Differential Diagnoses to Exclude

Life-Threatening Causes

• Acute mesenteric ischemia from hypotension or thromboembolic events (7-100% incidence of thromboembolism in tetraparesis with inadequate prophylaxis) 1.
• Bowel perforation from unrecognized trauma or pressure-related ischemia.
• Acute colonic pseudo-obstruction (Ogilvie syndrome), which occurs with spinal cord injury and autonomic dysfunction 2.

Infectious Complications

• Intra-abdominal sepsis from catheter-related infections, aspiration pneumonia, or pressure ulcer-related bacteremia 1.
• Central line sepsis can present with systemic signs including ileus and abdominal distention 1.

Immediate Diagnostic Approach

Clinical Assessment

• Assess for peritoneal signs despite the challenge that neurologic deficit may mask abdominal pain and guarding.
• Check nasogastric tube patency and measure gastric residual volumes.
• Evaluate for signs of systemic infection (fever, leukocytosis, hemodynamic instability despite stated stability).

Imaging

• Obtain upright or cross-table lateral abdominal radiograph to assess for free air, bowel gas pattern, and gastric distention.
• CT abdomen/pelvis if peritonitis, perforation, or ischemia suspected.
• Assess for pneumoperitoneum which could indicate perforation.

Laboratory Evaluation

• Complete blood count, lactate, liver function tests, lipase, and inflammatory markers.
• Blood cultures if sepsis suspected.

Management Priorities

Immediate Interventions

• Insert or confirm patency of nasogastric tube for gastric decompression 1.
• Reduce BiPAP pressures if clinically tolerable to minimize gastric insufflation 1.
• Position patient in semi-recumbent position (30-45 degrees) if cervical spine stability permits 1.

Pharmacologic Management

• Initiate prokinetic agents (metoclopramide or erythromycin) for gastroparesis.
• Consider neostigmine for colonic pseudo-obstruction if large bowel distention confirmed and perforation excluded.
• Ensure adequate DVT prophylaxis given the 7-100% thromboembolism risk 1.

Nutritional Adjustments

• Temporarily hold enteral feeds until distention resolves.
• Consider post-pyloric feeding tube placement to bypass gastric stasis 1.

Common Pitfalls to Avoid

• Do not assume hemodynamic stability excludes mesenteric ischemia—early ischemia may present before cardiovascular collapse.
• Do not attribute all distention to ileus without excluding mechanical obstruction or perforation—these require surgical intervention.
• Do not overlook thromboembolic complications—cervical spine injury patients have exceptionally high VTE risk 1.
• Do not delay decompression—prolonged gastric distention increases aspiration risk and can lead to gastric necrosis.