ACLS Advanced Cardiac Life Support

Part 1: Basic Airway Management

Devices to Provide Supplementary Oxygen

Overview            Oxygen administration is often necessary for patients with acute cardiac disease, pulmonary distress, or stroke. Supplementary oxygen administration, ideally, should be titrated to the lowest concentration required to maintain Sp O₂ ≥94%. Various devices can deliver supplementary oxygen from 21% to 100% (Table 1) . This section describes 4 devices to provide supplementary oxygen:Nasal cannulaSimple oxygen face mask Venturi mask Face mask with O₂ reservoir Whenever you care for a patient receiving supplementary oxygen, quickly verify the proper function of the oxygen delivery system in use.

Table 1. Delivery of Supplementary Oxygen: Flow Rates and Percentage of Oxygen Delivered.

A nasal cannula provides up to 44% oxygen. In this low-flow system, inspired air mixes with room air. The ultimate inspired oxygen concentration is determined by the oxygen flow rate through the cannula and how deeply and rapidly the patient breathes (minute ventilation).

Increasing the oxygen flow by 1 L/min (starting with 1 L/min) will increase the inspired oxygen concentration by approximately 4%.

Indications:

Patients with adequate spontaneous respiratory effort, airway protective mechanism, and tidal volumePatients with arterial oxyhemoglobin saturation <94% Patients with minimal respiratory or oxygenation problems Patients who cannot tolerate a face mask

Figure 1. A nasal cannula used for supplementary oxygen delivery in spontaneously breathing patients.

Simple The simple oxygen face mask delivers low-flow oxygen to the Oxygen patient’s nose and mouth. It can supply up to 60% oxygen with flow Face Mask rates of 6 to 10 L/min, but the final oxygen concentration is highly dependent on the fit of the mask (Table 1). Oxygen flow rate of at least 6 L/min is needed to prevent rebreathing of exhaled CO₂ and to maintain increased inspired oxygen concentration.

Venturi Venturi mask enables a more reliable and controlled delivery of Mask oxygen concentrations from 24% to 50% (Table 1). Deliveredoxygen concentrations can be adjusted to 24%, 28%, 35%, and 40% using a flow rate of 4 to 8 L/min and 40% to 50% using a flow rate of 10 to 12 L/min. Observe the patient closely for respiratory depression. Use a pulse oximeter to titrate quickly to the preferred level of oxygen administration.

A Venturi mask can accurately control the inspired oxygen concentration. Use this mask in patients with chronic obstructive pulmonary disease (COPD), who usually have chronic hypercarbia (high CO₂) and mild to moderate hypoxemia. Administration of high oxygen concentrations to patients with end-stage COPD may produce respiratory depression because the increase in PaO₂ eliminates the stimulant effect of hypoxemia on the respiratory centers.

Never withhold oxygen from patients who have respiratory distress and severe hypoxemia simply because you suspect a hypoxic ventilatory drive. If oxygen administration depresses respiration, support ventilation.

Face Mask   The face mask with oxygen reservoir is a partial rebreathing mask

With                that consists of a face mask with an attached reservoir bag (Figure

Oxygen          2). A face mask with oxygen reservoir (nonrebreathing mask)

Reservoir       provides up to 95% to 100% oxygen with flow rates of 10 to 15 L/min

(Table 1). In this system a constant flow of oxygen enters an

attached reservoir.

Figure 2. A face mask with oxygen reservoir used for supplementary oxygen delivery in spontaneously breathing patients. Use of a face mask with a reservoir is indicated for patients who Are seriously ill, responsive, spontaneously breathing, have adequate tidal volume, and require high oxygen concentrations May avoid endotracheal intubation if acute interventions produce a rapid clinical effect (eg, patients with acute pulmonary edema, COPD, or severe asthma) Have relative indications for advanced airway management, but maintain intact airway protective reflexes, such as gag and cough Have relative indications for advanced airway management, but have physical barriers to immediate intubation, such as cervical spine injury  Are being prepared for advanced airway management

always requires close monitoring. Suctioning devices should be immediately available. Additionally, prolonged exposure to high inspired oxygen concentration could be detrimental when PaO₂ is high (ie, >300 mm Hg) and arterial oxyhemoglobin saturation is 100%. When feasible, the minimum supplementary oxygen needed to maintain arterial oxyhemoglobin saturation ≥94% should be used.