Table 2

Study variables of patients in the positive and negative Air-Test results groups also assessed with a reference standard CT scan

Positive Air-Test result (n=30)Negative Air-Test result (n=29)p Value
Demographic data
 Age, years62 (13)53 (15)0.045
 Women, n (%)12 (40)11 (37)0.57
 Height, cm165 (10)163 (12)0.32
 Body weight, kg88 (29)75 (17)<0.001
 ARISCAT score28 (14)14 (15)<0.001
 Preoperative SpO2, %98 (2)98 (2)0.28
 Lower abdominal surgery39 (10)29 (5)0.20
 Upper abdominal surgery6 (3)4 (3)0.11
 Peripheral surgery, %55 (11)67 (7)0.06
 Duration of surgery, min137 (62)119 (63)0.27
Intraoperative ventilatory management
 Tidal volume, mL472 (50)466 (92)0.56
 Respiratory rate, breaths/min12 (1)12 (2)1.00
 PEEP, cmH2O6 (1)6 (2)1.00
 FiO20.7 (0.2)0.7 (0.3)0.90
SpO2 and arterial blood gases at PACU at the end of the Air-Test
 Postoperative SpO2, %92 (3)99 (1)0.01
 PaO2, mm Hg78 (21)90 (10)<0.001
 PaCO2, mm Hg40 (6)42 (6)0.34
 pH7.37 (0.04)7.38 (0.03)0.09
 MAP, mm Hg81 (12)76 (15)0.72
 Lactate, mmol/L1.1 (0.4)1.0 (0.6)0.52
 Hb, g/dL12.5 (1.2)12.3 (1.6)0.41
 Temperature, °C36.2 (1.9)36.2 (2.3)0.68
 VAS1 (1)1 (1)1.00
  • Data are described as mean (SD) or number/total number (%). The ARISCAT score was used to predict postoperative pulmonary complications.22

  • ARISCAT, Assess Respiratory Risk in Surgical Patients in Catalonia; FiO2, inspiratory oxygen fraction; Hb, haemoglobin; MAP, mean arterial pressure; PaCO2, carbon dioxide partial pressure; PACU, postanaesthesia care unit; PaO2, arterial oxygen partial pressure; PEEP, positive end-expiratory pressure; pH, acid–base status; SpO2, pulse oximetry haemoglobin saturation; VAS, visual analogue scale.