Table 1. Summary of characteristics and possible confounding factors of group A–E.

Surgery duration is presented as mean and standard deviation. Intra-abdominal pressure, number of people in the operating theatre and carbon dioxide concentration are presented as median and range. Number of people in operating theater excludes the patient.

	Group	Location	Surgeries (n)	Observations (n)	IAP (mmHg)	People in OT (n)	Duration (min)	Gas detector CO 2 (ppm)
Cholecystectomy	A	DSU	6	52	12 [12–12]	7 [5–7]	77 (19)	600 [400–600]
	B	NGSW	3	30	12 [12–12]	7 [6–7]	90 (26)	700 [600–1100]
Hernia repair	C	NGSW	4	40	12 [12–14]	6 [6–7]	90 (22)	700 [600–1000]
Intestinal surgery	D	OGSW	2	35	13 [12–14]	9 [7–10]	165 (120)	600 [600–1000]
	E	NGSW	5	57	14 [12–14]	7 [5–8]	113 (85)	700 [600–800]
Total			20	210				700 [400–1100]

IAP intra-abdominal pressure, CO ₂ carbon dioxide, OT operating theatre, OGSW old general surgery ward, NGSW new general surgery ward, DSU day surgery unit, ppm parts per million