Influence of perioperative oxygen fraction on pulmonary function after abdominal surgery: a randomized controlled trial

Abstract

BackgroundA high perioperative inspiratory oxygen fraction (FiO2) may reduce the frequency of surgical site infection. Perioperative atelectasis is caused by absorption, compression and reduced function of surfactant. It is well accepted, that ventilation with 100% oxygen for only a few minutes is associated with significant formation of atelectasis. However, it is still not clear if a longer period of 80% oxygen results in more atelectasis compared to a low FiO2.Our aim was to assess if a high FiO2 is associated with impaired oxygenation and decreased pulmonary functional residual capacity (FRC).MethodsThirty-five patients scheduled for laparotomy for ovarian cancer were randomized to receive either 30% oxygen (n = 15) or 80% oxygen (n = 20) during and for 2 h after surgery. The oxygenation index (PaO2/FiO2) was measured every 30 min during anesthesia and 90 min after extubation. FRC was measured the day before surgery and 2 h after extubation by a rebreathing method using the inert gas SF6.ResultsFive min after intubation, the median PaO2/FiO2 was 69 kPa [53-71] in the 30%-group vs. 60 kPa [47-69] in the 80%-group (P = 0.25). At the end of anesthesia, the PaO2/FiO2 was 58 kPa [40-70] vs. 57 kPa [46-67] in the 30%- and 80%-group, respectively (P = 0.10). The median FRC was 1993 mL [1610-2240] vs. 1875 mL [1545-2048] at baseline and 1615 mL [1375-2318] vs. 1633 mL [1343-1948] postoperatively in the 30%- and 80%-group, respectively (P = 0.70).ConclusionWe found no significant difference in oxygenation index or functional residual capacity between patients given 80% and 30% oxygen for a period of approximately 5 hours.Trial registrationClinicalTrials.gov Identifier: NCT00637936.

Effect of Intraoperative High Inspired Oxygen Fraction on Surgical Site Infection, Postoperative Nausea and Vomiting, and Pulmonary Function

“…3B) (table 3). 55,56,60,61,63,64,69,70,72 Six articles reported on atelectasis using chest radiographs and/or thoracic computed tomography scans for diagnosis (table 4); however, two of those 69,70 were subgroup analyses reporting on the same outcomes as the original larger study. 63 Thus, data from four trials, two small 56,60 and two large, 63,64 could be combined (fig.…”

“…55,60,69 In one, 55 there was an evidence of statistically significant worsening of the intraoperative Pao 2 / FIo 2 ratio in patients receiving 100% FIo 2 (use of positive end-expiratory pressure and postoperative Pao 2 /FIo 2 ratio was not reported). The two other studies failed to show any detrimental effect on the postoperative Pao 2 /FIo 2 ratio with supplemental oxygen, 60,69 despite the use of 100% oxygen and no positive end-expiratory pressure in one trial. 60 Three small studies reported on lung function (table 4).…”

“…5 Results of another multicenter study reporting on SSI and pulmonary outcomes 63 were reported in two further articles; one concentrated on pulmonary outcomes in obese patients 70 and the other on pulmonary outcomes in patients scheduled for laparotomy for ovarian cancer. 69 …”

“…[4][5][6][7][27][28][29][30][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72] Seven reports with additional data from 900 patients have not been considered for any previously published metaanalyses. [27][28][29][30]61,69,70 Two articles reporting on pulmonary outcomes 56 and PoNV, 7 respectively, were subgroup analyses of a multicenter study that reported on SSI. 5 Results of another multicenter study reporting on SSI and pulmonary outcomes 63 were reported in two further articles; one concentrated on pulmonary outcomes in obese patients 70 and the other on pulmonary outcomes in patients scheduled for laparotomy for ovarian cancer.…”

Inspiratory Oxygen Fraction and Postoperative Complications in Obese Patients

“…10 Another subgroup study of the PROXI Trial involving 35 patients showed no significant difference in change in oxygenation index or functional residual capacity when 80% oxygen was administered than when 30% oxygen was used. 36 Less evidence of the effect of ventilation with high oxygen is available in obese patients, but morbidly obese patients are more prone to perioperative atelectasis formation, and the atelectasis remains unresolved for a longer period after surgery than occurs in nonobese patients. 1 One recent study of 142 moderately obese patients found a minimal reduction in postoperative lung function when patients were given 80%, compared with 40%, oxygen during minor peripheral surgery.…”