Table 2.

Key demographic and surgical factors related to mortality.

	Case 1 (7-day mortality)	Case 2 (31-day mortality)
COVID-19 status	Swab test negative, no symptoms of COVID-19	COVID-19 negative throughout initial hospital admission, including operation. Discharged home and later re-admitted, with subsequent COVID-positive swab test (day-10 post-operatively)
Age	>65 years old	>65 years old
ASA grade	IV	III
Urgency of surgery	NHS England priority level 2	NHS England priority level 2
Complexity of surgery	Neurosurgical resection, neck dissection and free flap reconstruction	Coronary artery bypass grafts complicated by sternal dehiscence and sternal osteomyelitis, requiring multiple repeat debridements and omental flap reconstruction through laparotomy
Surgical time	17.8 h	2.1 h
Post-operative complications	Clavien-Dindo grade 4 and 5 (stroke, respiratory failure requiring ventilation and death)	Clavien-Dindo grade 4 and 5 (COVID pneumonia, respiratory failure and death)
Death	Day 7 post-operatively	Day 31 post-operatively
Mortality rate	0.2% 30-day mortality rate	0.4% overall mortality rate