The Administration of Supplementary Oxygen to Prevent Hypoxia During Upper Alimentary Endoscopy

Abstract

A prospective, randomized, controlled trial was conducted in 200 consecutive patients undergoing endoscopy of the upper alimentary tract. One hundred patients received supplementary oxygen at 4 liters/minute through nasal cannulae, while 100 patients received no additional oxygen. Within each of these two groups, 50 patients were sedated with midazolam and 50 patients with diazepam suspension ("Diazemuls"). The patients' weights were recorded and correlated with their height to assess whether they were over or under their ideal weight. Oxygen saturation was recorded at baseline and throughout the endoscopic procedure. The principal finding of this study was that hypoxia (oxygen saturation less than 93%) was prevented in all cases by the administration of 4 liters/minute of oxygen, whereas 48 of the 100 patients who did not receive oxygen exhibited falls in oxygen saturation to less than 93% (p < 0.0001). Those with the highest risk were the obese patients (p < 0.01). There was no significant difference between the two sedative drug groups in either frequency or severity of associated hypoxia (p = 0.77, patients not given oxygen; p = 0.31, patients receiving oxygen). The cost of administering oxygen during upper gastrointestinal endoscopy would be an average of 95 pence ($1.60) per patient. In conclusion, the administration of oxygen during endoscopy is a worthwhile prophylactic measure to prevent hypoxia and its potential adverse effects.

Risk Factors for Hypoxemia During Ambulatory Gastrointestinal Endoscopy in ASA I–II Patients

“…We also found BMI correlated with the number of hypoxemic episodes and that hypoxemia was numerically more frequent in obese patients compared with nonobese patients. Risk factors for hypoxemia have been evaluated in several studies [4][5][6][7][8][9][10][11][12][13], but a lack of a uniform definition of hypoxemia makes comparison across the studies difficult. This difficulty is further compounded by differences in patient populations, type of endoscopy, use of supplemental oxygen, and type of sedation agents [4][5][6][7][8][9][10][11][12][13][14][15].…”

“…Risk factors for hypoxemia have been evaluated in several studies [4][5][6][7][8][9][10][11][12][13], but a lack of a uniform definition of hypoxemia makes comparison across the studies difficult. This difficulty is further compounded by differences in patient populations, type of endoscopy, use of supplemental oxygen, and type of sedation agents [4][5][6][7][8][9][10][11][12][13][14][15]. Therefore, the incidence of hypoxemia during conscious sedation for gastrointestinal endoscopy has ranged widely, between 10% and 70% [4][5][6][7][8][9][10][11][12][13][14][15].…”

“…This difficulty is further compounded by differences in patient populations, type of endoscopy, use of supplemental oxygen, and type of sedation agents [4][5][6][7][8][9][10][11][12][13][14][15]. Therefore, the incidence of hypoxemia during conscious sedation for gastrointestinal endoscopy has ranged widely, between 10% and 70% [4][5][6][7][8][9][10][11][12][13][14][15]. Overall, conscious sedation is overwhelmingly safe, with a very low risk of death, requirement for artificial ventilation, myocardial infarction, or central nervous system damage.…”

“…Due to the confounding effect of the ASA class within the diverse populations in the previous reports, risk factors of hypoxemia within ASA I and II patients, who constitute the majority of ambulatory patients, are not well defined. Secondly, the relationships between body weight and hypoxemia have not been clearly defined in previous studies [8,12,13]. Therefore, our aims for this study were to evaluate the risk factors of hypoxemia in ASA I and II patients during moderate sedation for ambulatory endoscopic procedures and to evaluate the relationship between body mass index (BMI) and hypoxemia.…”

“…Previous studies have evaluated the risk factors of hypoxemia in both retrospective and prospective methods with disparate results [4][5][6][7][8][9][10][11][12][13]. A majority of the reports found the American Society of Anesthesiology (ASA) classification to be the most significant overall risk factor.…”