The Value of Consistent Emergency Care
Medical professionals avoid the risk of forcing hazardous materials into the nasal cavity via the lacrimal system This is the best approach.
It has always amazed me how a simple thing such as a lack of communication can not only lead to less-than-optimal results, but also that the sub-par performance can sometimes continue for decades! No example of this phenomenon is more readily apparent than the traditional approach used to irrigate injured eyes in commercial or industrial facilities.
The idea behind commercial plumbed-in eyewashes is simple: to irrigate injured eyes with copious amounts of water aimed at removing foreign (often hazardous) materials, while also cooling the area in instances of chemical splash incidents. It’s certainly not a new idea; it has been around for the better part of six decades. And for every one of those six decades, the safety equipment industry has been irrigating eyes in a, shall we say, less-than-optimal direction.
Plumbed-in eyewashes have traditionally been designed to focus twin streams of water aimed upward and in toward each other, roughly forming what looks like a “McDonald’s Arc.” An injured worker activates the eyewash and places his or her face down into the twin streams, allowing the streams to enter the eyes from the outboard corners. The irrigating water would then flow inward across both eyes toward the nose, exiting the eye surfaces roughly at the bridge of the nose.
In contrast, the medical community irrigates eyes in the exact opposite direction: Irrigating fluid is introduced into the eye at the inner corner, or canthus, and is allowed to flow gently toward the outer corner. The logic behind the universally accepted medical approach is simple: Medical professionals avoid the risk of forcing hazardous materials into the nasal cavity via the lacrimal system.
The Physiology of the Human Eye
The human eye is equipped with an automatic lubricating and cleansing mechanism called the lacrimal system (see Figure 1). It consists of the lacrimal gland, which produces tears; the ducts that channel tears from the lacrimal gland to the ocular cavity; and the lacrimal puncta. which are drains that channel excess fluids out of the ocular surface. Importantly, the lacrimal puncta drain excess fluids directly into the nasal cavity. This is the reason why your nose runs when you cry.
The eyelid also plays a critical role.As we blink, the eyelid wipes the cornea, pushing contaminants and excess fluids toward the lacrimal puncta, or the ocular surface’s drains. If a hazardous material is introduced into the eye, nature’s own cleansing mechanism can serve to force the contaminant into the nasal cavity, where it can be breathed into the lungs or swallowed. Obviously, this is not the ideal situation!
Proper Eye Irrigation
As mentioned earlier, the medical profession teaches and practices irrigating eyes by introducing the flushing fluid at the inner corner of the eye -- adjacent to the nose -- and letting it run across the eye to the outer edge. In effect, we irrigate by moving the fluid away from the lacrimal puncta. This is opposite the flow direction of traditional, plumbed-in eyewash products. Pushing contaminants toward the nose risks introducing them into the nasal cavity, where, again, they can be breathed in or swallowed.
The ideal method of irrigating eyes in a commercial or industrial setting is to use plumbed-in products that mirror approved medical protocols.Eyewash streams that are inverted versus the traditional eyewash contact the eyes at the inner canthus or corner, adjacent to the bridge of the nose.Contaminants are thus swept to the outer edge of the eye, where gravity takes over, running them into the eyewash bowl. This approach offers the greatest amount of security possible to the lacrimal puncta.
Comfort for the Victim
Don’t forget about the comfort of the victim in specifying eyewash equipment. As I have reviewed the available products on the market today, very few meet my criteria for effective and comfortable flows. As I understand it, the ANSI standard governing eyewash operation calls for a minimum flow rate of 0.4 gallons per minute for eyewashes and 3.0 gpm for eye and face wash products. These flow rates must be maintained for the full prescribed 15-minute irrigation cycle.
Like most things in our society, these minimums have been exceeded in product designs almost across the board. It’s a “more is better” kind of world we live in today! Unfortunately, it is pretty common to find eye and face wash products, for example, that flow in excess of 5 gpm. Products without proper flow controls also can experience fluctuations based on line pressure surges, as well. One would be hard pressed to find an uninjured volunteer capable of staying in those streams for 15 minutes.
Specifiers should seek out products that meet the ANSI requirements on the low side and are equipped with flow controls and stream designs that maximize victim comfort during use. Let’s face it, providing the best equipment money can buy isn’t going to help if employees won’t use it.
One final point on irrigating stream comfort: Recent developments have introduced the use of laminar flow designs in eyewash and eye/face wash products. A laminar flow is one in which there is an absence of turbulence because the stream is “built” in layers.Turbulence or inconsistencies in the flow stream can strike the eye as a change in total pressure, making the victim much less comfortable with the process. The best approach is providing an even, comfortable, predictable stream height and circumference, accomplished by using laminar design principles.
The Next Wave of Change
Years ago, it may have been acceptable to assume a certain number of injuries, even fatalities, as a part of the planning for major projects. Workers seem to have been considered more an expendable piece of equipment than a valuable asset to be protected and safeguarded. That changed as part of a greater awareness of the value of human capability and with an increased sense of morality in the overall business mentality. And, certainly, the dawn of watchdog functions, such as OSHA, to administer practical standards such as the ANSI guidelines, took us to even greater levels of safety and response excellence.
Advancements in making available products to safeguard workers and respond to emergencies during the past half-century or more also have played a huge role in lowering incidents and mitigating their devastating effects. Today, products resulting from a collaboration between safety equipment manufacturers and the medical community are yet another step in the right direction.
This article originally appeared in the October 2008 issue of Occupational Health & Safety.