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Managing Postoperative Hypoxemia

By October 14, 2020 No Comments
Doctor using electrode on patient in operating theatre.

Postoperative hypoxemia is a serious yet common condition that requires immediate treatment. It occurs predominantly as the result of gas exchange impairment or abnormalities in breathing control that can result from prolonged sedation by means of general anesthesia or opioids.[1] Risk factors for post-operative hypoxemia include heart disease, low pre-operative oxygen saturation, and a surgical duration of more than three hours.[2] All methods of intervention should seek to maintain oxygen at a target saturation rate—for a human adult, this is approximately 92-98 percent. Patients with chronic obstructive pulmonary disease should have a target saturation rate of around 88-92 percent.[3],[4]

There are a variety of strategies for treating postoperative hypoxemia. The ideal treatment for each patient may vary depending on postoperative state and existing risk factors; therefore, a complete respiratory assessment should be performed prior to determining a plan of action. For less severe cases, it may be sufficient to raise the head of the bed and place the patient in a Fowler’s or semi-Fowler’s position, therefore allowing gravity to maximize inhalation volume and promote chest expansion. When attending to conscious or semi-conscious patients, deep breathing and coughing techniques may also be effective for restoring oxygenation. However, for patients that may require additional assistance or those that are already on supplemental oxygen, direct administration will likely be necessary. When performing oxygen therapy, the exit ports of oxygen flow should be placed directly into the patients’ nostrils to maximize intake; both oxygen tank levels and the integrity of the connecting tube should be monitored consistently. Bronchodilators are a slightly more invasive method of oxygen supplementation that may be preferable for patients with respiratory disease, as they perform a more active role in relaxing smooth muscle and opening airways. Oral suctioning may be necessary if the patient’s cough reflex is compromised and they are therefore unable to clear mucous and other debris from their pharynx or mouth.

Regardless of the methodology used to treat postoperative hypoxemia, it is essential to check cardiovascular and respiratory vital signs within the next several minutes following application. If there is indication that hypoxemia is persisting, more rigorous or additional methods of oxygen supplementation may be necessary.


References

[1] Jones JG, Sapsford DJ, Wheatley RG. Postoperative hypoxaemia: mechanisms and time course. Anaesthesia 45: 566–573, 1990.

[2] Melesse DY, Denu ZA, Kassahun HG, Agegnehu AF. The incidence of early post-operative hypoxemia and its contributing factors among patients underwent operation under anesthesia at University of Gondar comprehensive and specialized referral hospital, Gondar, North West Ethiopia, 2018. A prospective observational study. International Journal of Surgery Open 22: 38–46, 2020.

[3] Austin MA, Wills KE, Blizzard L, Walters EH, Wood-Baker R. Effect of high flow oxygen on mortality in chronic obstructive pulmonary disease patients in prehospital setting: randomised controlled trial. BMJ. 2010;341:c5462.

[4] Long-Term Oxygen Treatment Trail Research Group. A randomized trial of long-term oxygen for COPD with moderate desaturation. N Engl J Med. 2016;375(17):1617-1627. 

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