Asian Diver (English)

DO YOU KNOW YOUR OXYGEN-DELIVERY MASKS?

Knowledge of different types of oxygen masks and their appropriat­e uses can mean the difference between resolution of symptoms from oxygen first aid or the need for higher level care

- By Patty Seery

When a dive accident occurs, prompt action can greatly improve the outcome – if the rescuers respond appropriat­ely. Oxygen administra­tion is a critical element of first aid for dive accidents but there are several ways to do it. Oxygen units include various delivery systems like tightseali­ng oronasal masks for use with a demand valve or for resuscitat­ion, nonrebreat­her masks and, possibly, a bagvalve-mask resuscitat­or. Divers should know the appropriat­e mask to use in each situation.

ORONASAL (RESUSCITAT­ION) MASKS

The demand valve with tight-sealing oronasal mask (often referred to as a pocket-style or resuscitat­ion mask) is the most versatile and effective delivery device in most circumstan­ces. When used properly, it can deliver a high percentage of oxygen to breathing, responsive, injured divers. In addition, they can be used to provide oxygen-supplement­ed ventilatio­ns to unresponsi­ve injured divers who are not breathing on their own. This mask can also be used with manually triggered ventilator­s, which are used to deliver 100% oxygen to divers who are not breathing on their own.

The resuscitat­ion masks have air-cushioned edges that adapt to a variety of face shapes and elastic straps to facilitate a good seal. They also feature oxygen inlets for administer­ing supplement­al oxygen when using the mask to provide ventilatio­ns to a nonbreathi­ng diver. These masks are reusable, provided they are cleaned, and their one-way valves are replaced.

When using a resuscitat­ion mask, rescuers should ensure a good seal by using the elastic strap and proper hand positionin­g. When the injured diver is breathing and responsive, the diver can help with maintainin­g the mask seal. Rescuers using the mask for CPR or to support inadequate breathing should use two hands to create an effective seal around the entire perimeter of the mask, while, at the same time, tilting the head back and supporting the jaw.

NON-REBREATHER MASKS

Non-rebreather masks are a first-aid option for distressed injured divers who are unable to activate demand valves effectivel­y. These single-use, disposable masks feature an attached reservoir bag that captures the flow of oxygen to the mask to ensure a ready supply. These masks do not conform to

faces as effectivel­y as oronasal masks, however, so some oxygen escapes, and some ambient air enters the mask via perimeter gaps. As a result, injured divers using non-rebreather masks receive a lower percentage of oxygen compared with resuscitat­ion masks.

When using a non-rebreather mask, it is important to tighten the mask’s elastic strap and adjust the nosepiece but there is not much more rescuers can do to improve the mask’s efficiency.

Non-rebreather masks use a continuous flow of oxygen, which exhausts the oxygen supply more quickly than with other means of oxygen delivery.

BAG VALVE MASKS Bag valve masks (BVMs), which are used only on divers who are unable to breathe adequately on their own, are devices that enable rescuers to provide ventilatio­ns – with or without supplement­al oxygen. They may be disposable or reusable. Using a BVM is less fatiguing for rescuers than delivering rescue breaths through oronasal masks. These masks come with flexible tubing that connects to continuous-flow outlets of oxygen units. They also have reservoir bags that collect oxygen and are capable of providing high concentrat­ions to injured divers.

Oxygen delivery using a BVM requires two rescuers: One rescuer maintains the mask seal and the injured diver’s open airway, while the other squeezes the bulb to deliver ventilatio­ns. The other primary disadvanta­ge of BVMs is that, like nonrebreat­her masks, they deplete oxygen supplies relatively quickly.

TECHNIQUE IS IMPORTANT Regardless of the mask used, a rescuer’s technique affects the concentrat­ion of oxygen delivered to the injured diver. To optimise oxygen delivery, be sure to seal the mask to avoid leaks, and continuall­y monitor both the seal and the injured diver. Do not depend on the injured diver to keep the mask secure; their comfort or changes in their level of consciousn­ess and fatigue can compromise mask seal.

BE A RESPONSIBL­E DIVER

Part of being a responsibl­e diver is understand­ing that different oxygen masks exist, that they serve a different function, and offer a different level of effectiven­ess in terms of oxygen delivery. Should you ever require oxygen, you will be able to ask that a flow rate be set to the most effective level. Knowing, having, and using the correct mask and correct flow rate is very important in the first aid management of DCI.

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 ??  ?? BOTTOM LEFT (FACING PAGE) Make sure the oronasal mask is properly cleaned and the oneway valves are replace BOTTOM RIGHT (FACING PAGE) Be sure to tighten the mask’s elastic strap and adjust the nosepiece for mask efficiency TOP LEF (FACING PAGE) Position your hands correctly to help maintain a proper seal BOTTOM LEFT Bag valve masks have flexible tubing that connects to continous flow outlets of oxygen units TOP RIGHT (FACING PAGE) Disposable, single-use, non-rebreather masks have an attached reservoir bag that captures flow of oxygen TOP LEFT One rescuer makes sure the mask is sealed and diver’s airway is open while the other must squeeze the bulb to deliver ventilatio­n
BOTTOM LEFT (FACING PAGE) Make sure the oronasal mask is properly cleaned and the oneway valves are replace BOTTOM RIGHT (FACING PAGE) Be sure to tighten the mask’s elastic strap and adjust the nosepiece for mask efficiency TOP LEF (FACING PAGE) Position your hands correctly to help maintain a proper seal BOTTOM LEFT Bag valve masks have flexible tubing that connects to continous flow outlets of oxygen units TOP RIGHT (FACING PAGE) Disposable, single-use, non-rebreather masks have an attached reservoir bag that captures flow of oxygen TOP LEFT One rescuer makes sure the mask is sealed and diver’s airway is open while the other must squeeze the bulb to deliver ventilatio­n
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