Oxygen: friend or foe in peri‐operative care?

Perioperative hyperoxia: perhaps a malady in disguise

“…The harm caused by excess FiO 2 is almost always iatrogenic and can be prevented with careful use of oxygen. A recent review of current literature concludes that strong clinical evidence is insufficient for showing the benefit of high perioperative FiO 2 and warns off its routine use due its potential detrimental effects [2,4,36]. Apart from solely increasing FiO 2 , tissue oxygenation can be improved by ensuring adequate alveolar ventilation, improved diffusion capacity of the lung, sufficient hemoglobin level and optimal metabolic status [1].…”

“…Although a SpO 2 level nearing 100% is intuitively reassuring to prevent risk of life-threatening hypoxemia, increasing FiO 2 blindly just to achieve that may have more detrimental effects [2,4]. The primary goal of oxygen therapy is to increase oxygen available for aerobic metabolism, but it can also cause damage directly or via molecular sequelae of adverse metabolic alterations in perioperative period.…”

“…Its delivery is a simple and effective intervention for acutely ill, especially hypoxemic, patients and most clinical professionals feel comfortable prescribing, and perhaps even overusing it [1,2]. No guidelines for perioperative oxygen use exist.…”

AAGBI recommendations for standards of monitoring during anaesthesia and recovery 2015 - a further example of ‘aggregation of marginal gains’

“…Transferring a spontaneously breathing patient, most commonly breathing through their own airway or via a supraglottic airway, using a breathing system that cannot deliver less oxygen than in air, with a trained anaesthesia provider observing them, is not comparable to an intubated, ventilated patient. Similarly, a continued blanket recommendation that all patients should receive supplemental oxygen during recovery from surgery is disappointing when pulse oximetry is now ubiquitous and oxygen therapy is now recommended to be targeted to a predefined oxygen saturation in most situations where oxygenation is threatened [5]. This is exemplified in our unit where increasing numbers of oncology patients have received bleomycin therapy, and routine administration of oxygen in these patients would be detrimental.…”

Oxygen at Caesarean section: too much of a good thing?

“…7 Despite this though, there remains little evidence that the routine use of supplemental oxygen confers much benefit, and in fact may even harm the fetus. 1,5 Khaw et al found that while supplemental oxygen improved both maternal and umbilical venous PaO 2 , it also resulted in higher levels of the markers of lipid peroxidation, namely 8-isoprostane, malondialdehyde and hydroperoxide. This was accounted for by an excess of oxygen-free radical activity in both the child and mother.…”