OXYGEN ADMINISTRATION

OXYGEN ADMINISTRATION


It may be advisable or necessary under certain circumstances to administer supplemental oxygen gas (O2) to a person who would benefit from such therapy. Examples include those stricken with severe high-altitude pulmonary edema, acute severe congestive heart failure, decompression sickness (the bends), and so forth. Anyone who may be called on to use oxygen delivery equipment should be properly trained in its use ahead of time.


The equipment required to deliver oxygen includes a medical oxygen cylinder (tank), pressure gauge, pressure-reducing valve, flowmeter, tubing, and nasal cannula (tube) or facemask (with or without a reservoir bag).


Oxygen cylinders in the United States are usually painted green or have distinctive green markings. They come in two practical field sizes: D (20 in, or 50.8 cm, in length; carries 360 liters of oxygen) and E (30 in, or 76.2 cm, in length; carries 625 liters of oxygen). The length of time that oxygen can be delivered is calculated by dividing the tank capacity by the flow rate. For instance, a D cylinder can deliver 10 liters per minute for 36 minutes. To make the oxygen last longer, keep the flow rate to the lowest effective number.


The pressure gauge reading indicates how much oxygen remains in the cylinder. At full capacity, an oxygen tank is pressurized to 2,000 lb per square inch (psi). Thus, when the gauge indicates a pressure of 500 psi, one-fourth of the tank’s capacity for oxygen remains. At a reading of 200 psi, a tank is near empty.


The pressure gauge, pressure-reducing valve, and flowmeter combine to create the regulator, which reduces the pressure of the oxygen from that inside the tank to approximately 50 psi. This allows delivery to the victim at flow rates between 1 and 15 liters per minute.


The delivery device attached to the victim is either a two-pronged (one for each nostril) nasal cannula, or a mask, the latter with or without a reservoir bag. A nonrebreather is a mask with a reservoir bag attached by a one-way valve such that the victim can breathe oxygen that is delivered into the bag, but cannot exhale carbon dioxide back into the bag (he cannot “rebreathe” from the bag). The nonrebreather is used to deliver high concentrations (as a percent of inspired air, 80% to 90% oxygen at flow rates of 10 to 15 liters per minute) of oxygen. The reservoir bag should be kept at least half full of oxygen. This can be accomplished with flow rates of 6 liters per minute or greater.


If lesser concentrations of oxygen are adequate or desired, as with a patient who has chronic obstructive pulmonary disease (see page 47), a nasal cannula can be used. The cannula will deliver 25% to 40% oxygen at flow rates of 2 to 6 liters per minute. The nasal cannula is less confining in that the victim can speak, drink, and eat without having to remove a mask.


Since O2 is dry, it is often desirable to interpose a humidifying device when O2 delivery will be prolonged.


To administer oxygen:



1. Place the cylinder upright. Open and close the tank valve slowly (“crack the tank”) with a wrench to clean debris from the outlet.


2. Close the regulator flow valve and attach the regulator to the tank. Tighten securely by hand. Never use a regulator without the proper O-ring fitting. Never use tape to hold a loose regulator in place.


3. Open the tank valve slowly to half a turn beyond where the regulator becomes pressurized and there is a maximum reading on the pressure gauge.


4. Attach the plastic delivery tubing to the regulator outflow nipple. Attach the breathing mask or nasal cannula to the other end of the tubing, if it is not already attached.


5. Open the regulator flow valve to the desired flow rate in liters per minute (LPM). A regulator marking of “low” indicates 2 to 4 LPM, “medium” is 4 to 8 LPM, and “high” is 10 to 15 LPM. The flow rate for a nonrebreather mask should not be less than 6 LPM; the flow rate for a nasal cannula should not be more than 6 LPM.


6. Position the mask or cannula on the victim’s face. Adjust for comfort. Observe the victim to be certain that the device is tolerated, and that the reservoir bag fills properly.

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Aug 11, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on OXYGEN ADMINISTRATION

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