Association Between Nil Per Os Status and Intubated Patients Undergoing Surgery

J Surg Res. 2024 Mar:295:175-181. doi: 10.1016/j.jss.2023.10.015. Epub 2023 Nov 28.


Introduction: Patient outcomes heavily rely on nutritional support. However, holding enteric feeds prior to surgical operations in critically ill patients is still a common practice in intensive critical units. Our objective is to describe the relationship between duration of nil per os (NPO) and respiratory outcomes in intubated, critically ill patients requiring operative intervention.

Methods: We conducted a retrospective analysis on intubated, critically ill patients who underwent operative intervention between January 1, 2016, and December 31, 2018, to investigate how the duration of NPO status may affect respiratory outcomes. We compared adverse respiratory events among patients who maintain NPO ≥6 h (NPO group) versus those who were NPO <6 h (non-NPO group) prior to surgery.

Results: Two hundred patients met inclusion criteria: 104 for NPO and 96 for non-NPO. Aspiration event was found in 5.8% of NPO patients and 7.3% in non-NPO patients, P = 0.66. Desaturation event was found in 16.3% for NPO and 14.6% in non-NPO, P = 0.73. Pneumonia was found in 18.3% of NPO patients and 19.8% in non-NPO patients, P = 0.78. Reintubated rates were 13.5% for NPO and 16.7% for non-NPO, P = 0.57. Median (range) hours of NPO for non-NPO was 1.0 h (0-3.0) and 13.0 h (6.0-20.0) for NPO, P < 0.05.

Conclusions: For intubated, critically ill patients requiring operative intervention, there was no difference observed in adverse respiratory events between those kept NPO for 6 h or greater compared to those kept NPO for less than 6 h. Patients were commonly without enteric nutrition for periods of time much greater than the American Society of Anesthesia's recommended 6-h period.

Keywords: Critical care nutrition; Nil per os; Preprocedural fasting.

MeSH terms

  • Critical Illness* / therapy
  • Enteral Nutrition* / adverse effects
  • Humans
  • Retrospective Studies
  • Time Factors