Should fluid be withheld in a patient who is nil by mouth (nothing by mouth) and hypertensive with a pre-operative diagnosis of small bowel obstruction?

From the Guidelines

No, fluid should not be withheld in a patient who is nil by mouth (NPO) and hypertensive with a pre-operative diagnosis of small bowel obstruction. These patients require aggressive intravenous fluid resuscitation, typically with isotonic crystalloids such as 0.9% normal saline or lactated Ringer's solution, as recommended by the most recent guidelines 1. Initial fluid administration should be rapid, with 1-2 liters given over 1-2 hours, followed by maintenance fluids at 125-150 mL/hour, adjusted based on clinical response. Small bowel obstruction causes significant fluid sequestration in the obstructed bowel lumen and surrounding tissues, leading to intravascular volume depletion despite the patient appearing hypertensive. This hypertension may represent a stress response and can mask underlying hypovolemia. Adequate fluid resuscitation helps correct electrolyte imbalances, improves renal perfusion, and prepares the patient for potential surgery. Clinical parameters including urine output (target >0.5 mL/kg/hr), heart rate, blood pressure trends, and laboratory values should guide ongoing fluid management. Nasogastric tube decompression should also be initiated to relieve pressure in the obstructed bowel while fluid resuscitation continues. The latest evidence suggests that perioperative fluid management should be individualized, taking into account the type of surgery and important patient factors, including intravascular volume status and acute and chronic comorbidities 1. In the context of small bowel obstruction, the goal is to achieve euvolemia and correct any fluid and electrolyte deficits before surgery, as emphasized by the ERAS society recommendations 1. By prioritizing fluid resuscitation and individualized fluid management, we can optimize patient outcomes and reduce the risk of morbidity and mortality. Key considerations in fluid management include:

• Aggressive intravenous fluid resuscitation with isotonic crystalloids
• Individualized fluid management based on patient factors and surgery type
• Correction of fluid and electrolyte deficits before surgery
• Monitoring of clinical parameters to guide ongoing fluid management
• Nasogastric tube decompression to relieve pressure in the obstructed bowel. The most recent and highest quality study 1 supports the approach of individualized fluid management and aggressive fluid resuscitation in patients with small bowel obstruction.

From the Research

Fluid Management in Pre-operative Small Bowel Obstruction

• The provided studies do not directly address the question of whether to withhold fluid in a patient who is nil by mouth and hypertensive with a pre-operative diagnosis of small bowel obstruction.
• However, study 2 suggests that restricted postoperative IV fluid management in patients undergoing major abdominal surgery may be harmful, leading to an increased risk of major postoperative complications and a prolonged postoperative hospital stay.
• Study 3 discusses the management of adhesive small bowel obstruction, recommending initial conservative management with tube decompression and the use of water-soluble contrast medium for diagnostic and therapeutic purposes.
• Study 4 highlights the risk of post-operative gastric ileus leading to erratic absorption of oral pharmaceuticals, including antihypertensive medications, but does not provide guidance on fluid management in this context.
• Studies 5 and 6 present case reports of small bowel obstruction, but do not address fluid management in pre-operative patients.
• In the absence of direct evidence, it is unclear whether fluid should be withheld in this patient population, and further research or clinical guidelines may be necessary to inform decision-making 3, 2.