Continuing Education Activity
Oxygen administration may be initiated for a variety of reasons. Increased metabolic demand, maintenance of oxygenation while providing anesthesia, supplementation during treatment of lung illnesses that affect oxygen exchange, treatment of headaches, carbon monoxide exposure are a few examples for its initiation. Oxygen is necessary for basic metabolic demand in the body, and it is an important part of resuscitation in many acute illnesses, as well as maintenance of chronic hypoxemic diseases. This activity will highlight the mechanism of action, adverse event profile, and other key factors pertinent to members of the interprofessional team in the management of patients with hypoxemia and related conditions. This activity discusses the interprofessional evaluation and treatment of patients needing oxygen therapy.
- Identify the routes of administration, indications for, and complications of oxygen administration, as well as potential side effects and situations in which oxygen administration is contraindicated.
- Outline patient populations that benefit from oxygen administration.
- Review the considerations of oxygen administration.
- Summarize the most appropriate oxygen administration modalities for select patients and describe the role of the interprofessional team in appropriate treatment.
Clinicians initiate oxygen administration for a variety of reasons. Increased metabolic demand, maintenance of oxygenation while providing anesthesia, supplementation during treatment of lung illnesses that affect oxygen exchange, treatment of headaches, carbon monoxide exposure, and more are examples of reasons for its initiation. At sea level, the atmosphere consists of approximately 21 percent oxygen. As altitude increases, the percent of oxygen in the air decreases in a near-linear fashion. Adding supplemental oxygen or oxygen that is above the amount found in the atmosphere without alteration is most commonly delivered to the patient by nasal cannula, O2 mask (simple, non-rebreather, Venturi-mask) or added into a CPAP (continuous positive airway pressure) or BiPAP (bilevel positive airway pressure) system. The ventilator provides oxygen for intubated patients.
Anatomy and Physiology
Each patient's airway anatomy merits consideration to achieve optimal oxygenation of a patient. For example, a trauma patient with nasal passages occluded by blood would be sub-optimally provided supplemental oxygen using a nasal cannula, while for a patient with micrognathia, it might be challenging to achieve oxygenation goals using a sealed mask such as a CPAP or BiPAP system.
Oxygenation is optimal in an upright position, and awake patients requiring oxygenation support should be upright unless a contraindication to such positioning is present; contraindications include trauma before c-spine clearance, anatomy, patient risk, and level of sedation.
The most readily accepted indication for supplemental oxygenation is hypoxemia or decreased levels of oxygen in the blood. For the otherwise healthy patient, oxygen saturation targets are generally at 92 to 98%. For patients with chronic hypercapnic conditions, target oxygen saturations are generally between 88 to 92%, with oxygen administration indicated at saturations below these levels. This value is commonly measured with pulse oximetry, but a pulse oximeter can give falsely elevated readings in anemia, cyanide, or carbon monoxide poisoning and is not an adequate indicator of perfusion, as seen in cases of shock.
- Chronic obstructive pulmonary disease (COPD)
- Cystic fibrosis
- Pulmonary fibrosis
- Medical emergencies requiring high concentrations of oxygen in all cases:
- Major trauma
- Cardiac arrest and during resuscitation
- Carbon monoxide and cyanide poisonings
- Transfusion-related acute lung injury (TRALI)
- Medical emergencies which may or may not require oxygen administration
- Acute heart failure or heart failure exacerbations
- Pulmonary embolism
Historically, it is worth noting that acute myocardial infarction (AMI) receives treatment with morphine, oxygen administration, nitroglycerin, and aspirin; however, recent studies have shown routine oxygen administration to be non-beneficial.
Paraquat, a common herbicide, is toxic to humans, and poisoning by this substance is worsened by oxygen therapy due to its redox activity.
Carbon dioxide narcosis occurs in patients with conditions such as obstructive pulmonary disorders or chronic respiratory insufficiency that result in hypercarbia, over-administration of oxygen may reduce the respiratory drive. This reduction can result in further hypercarbia, altered mental status, or even complete respiratory collapse. Titrated therapy in hypoxemic patients with obstructive respiratory disease should merit consideration.
Neonates exposed to high levels of oxygen are at risk for developing retinopathy of prematurity, or ROP, as the oxygen promotes neovascularization of the retinas and can cause vision loss or blindness. Administration of vitamin E to premature neonates and antioxidants in adults may provide some protection for those infants requiring supplemental oxygenation.
Oxygen is highly flammable, and thus it poses a fire risk with use in proximity to open flames; this is particularly important in those patients who are having treatment for lung conditions associated with smoking, such as COPD. Concurrent use of supplemental oxygen and cigarettes can result in damage to person and property for oxygen users. Care is necessary with all flames, and careful storage of oxygen tanks is essential for patient safety.
Oxygen administration can increase insensible losses due to the use of dry (non-humidified) air, particularly at high flow rates. Additionally, in vulnerable patients, the administration of cool or even cold oxygen can increase the risk of hypothermia; this is easily mitigated by humidification and warming before administration.
Oxygen toxicity is an iatrogenic illness caused by exposure to high FIO2 during oxygen therapy. Oxygen saturation should be monitored in patients receiving supplemental O2. As the oxygen gets metabolized, some molecules convert to superoxide anions known as hydroxyl radicals, which are human tissue toxic. The resulting pathophysiological changes at the alveolar level result in decreases in lung compliance, diffusing capacity, and PaO2 levels. Central nervous system (CNS) toxicity can occur with exposure to high partial pressures of oxygen. Acute changes in the lungs resulting from oxygen toxicity consist of alveolar and interstitial edema, alveolar hemorrhages, and proteinaceous exudates. Further prolonged exposure to oxygen leads to a proliferative phase, which includes the proliferation of type II epithelial cells and fibroblasts, followed by collagen deposits. Exposure to FIO2s greater than 0.60 for as little as 24 to 48 hours can lead to severe irreversible pulmonary fibrosis.
Oxygen administration is one of the most common interventions in the acute care setting and is indicated in a wide variety of acute and chronic medical conditions. Health care professionals should be familiar with routes of oxygen administration, as well as the physiological effects of oxygen administration as a fundamental part of patient care.
Enhancing Healthcare Team Outcomes
Teams should be familiar with multiple modalities of oxygen administration, their initiation and use, as well as limitations of each modality. Although a clinician may order a specific type of oxygen administration and initially be the most appropriate, individual patients change, and their medical conditions evolve. Constant re-evaluation of the patient is critical to ensure that continued oxygen administration is necessary, as well as the route is the best possible for each patient. Respiratory therapists are often the team members initiating and monitoring methods of oxygenation, and vigilance from the respiratory therapist is vital in ensuring that the patient receives optimal therapy. Additionally, nurses, medical techs, and all other members of the team have a role to play in vigilant monitoring of the patient requiring acute oxygen administration for optimal patient-centered care. Patients placed on oxygen supplementation should have vigilant monitoring by pulse oximetry, and the patient's oxygen administration should undergo titration to parameters set forth by the patient's care team based on the most current evidence-based guidelines for each disease process. An interprofessional approach for patients receiving oxygen will result in the best outcomes. [Level 5]