Surgery and Perioperative Carecommon
A 66-year-old man is five days after an ultra-low anterior resection for rectal cancer and had initially been recovering well. Overnight he developed an irregular heart rate of 124/min, confirmed on ECG as new atrial fibrillation. This morning his temperature is 38.2°C and respiratory rate 24/min, and he reports worsening lower abdominal pain, with tenderness in both lower quadrants. His chest is clear to auscultation, oxygen saturation is 95% on room air, and the wound looks clean. Which one of the following is the most likely cause of his deterioration?