The role of hyperbaric oxygen therapy in the management of perioperative peripheral nerve injury: a scoping review of the literature.

BACKGROUND/IMPORTANCE: Peripheral nerve injury is an uncommon but potentially catastrophic complication of anesthesia and surgery, for which there are limited effective treatment options. Hyperbaric oxygen therapy is a unique medical intervention which improves tissue oxygen delivery and reduces ischemia via exposure to oxygen at supra-atmospheric partial pressures. While the application of hyperbaric oxygen therapy has been evidenced for other medical conditions involving relative tissue ischemia, its role in the management of peripheral nerve injury remains unclear. OBJECTIVE: This scoping review seeks to characterize rehabilitative outcomes when hyperbaric oxygen therapy is applied as an adjunct therapy in the treatment of perioperative peripheral nerve injury. EVIDENCE REVIEW: The review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for scoping reviews, using a systematic screening and extraction process. The search included articles published from database inception until June 11, 2022, which reported clinical outcomes (in both human and non-human models) of peripheral nerve injury treated with hyperbaric oxygen therapy. FINDINGS: A total of 51 studies were included in the narrative synthesis. These consisted of animal (40) and human studies (11) treating peripheral nerve injury due to various physiological insults. Hyperbaric oxygen therapy protocols were highly heterogenous and applied at both early and late intervals relative to the time of peripheral nerve injury. Overall, hyperbaric oxygen therapy was reported as beneficial in 88% (45/51) of included studies (82% of human studies and 90% of animal studies), improving nerve regeneration and/or time to recovery with no reported major adverse events. CONCLUSIONS: Existing data suggest that hyperbaric oxygen therapy is a promising intervention in the management of perioperative peripheral nerve injury, in which tissue ischemia is the most common underlying mechanism of injury, neurological deficits are severe, and treatment options are sparse. This positive signal should be further investigated in prospective randomized clinical trials.

The role of routine pulmonary imaging before hyperbaric oxygen treatment.

Respiratory injury during or following hyperbaric oxygen treatment (HBOT) is rare, but associated pressure changes can cause iatrogenic pulmonary barotrauma with potentially severe sequelae such as pneumothoraces. Pulmonary blebs, bullae, and other emphysematous airspace abnormalities increase the risk of respiratory complications and are prevalent in otherwise healthy adults. HBOT providers may elect to use chest X-ray routinely as a pre-treatment screening tool to identify these anomalies, particularly if a history of preceding pulmonary disease is identified, but this approach has a low sensitivity and frequently provides false negative results. Computed tomography scans offer greater sensitivity for airspace lesions, but given the high prevalence of incidental and insignificant pulmonary findings among healthy individuals, would lead to a high false positive rate because most lesions are unlikely to pose a hazard during HBOT. Post-mortem and imaging studies of airspace lesion prevalence show that a significant proportion of patients who undergo HBOT likely have pulmonary abnormalities such as blebs and bullae. Nevertheless, pulmonary barotrauma is rare, and occurs mainly in those with known underlying lung pathology. Consequently, routinely using chest X-ray or computed tomography scans as screening tools prior to HBOT for low-risk patients without a pertinent medical history or lack of clinical symptoms of cardiorespiratory disease is of low value. This review outlines published cases of patients experiencing pulmonary barotrauma while undergoing pressurised treatment/testing in a hyperbaric chamber and analyses the relationship between barotrauma and pulmonary findings on imaging prior to or following exposure. A checklist and clinical decision-making tool based on suggested low-risk and high-risk features are offered to guide the use of targeted baseline thoracic imaging prior to HBOT.