Your patient is an ill worker on the top of a water tank. You’ve packaged them in a Stokes litter and, due to the location of anchors, you’ve chosen to lower them down the enclosed ladder cage. Due to the size of the ladder cage, the litter will need to be rigged to be lowered in a vertical position. A litter attendant will not be used.
Sounds like a simple rigging operation, right? Maybe. Do your personnel practice rigging the litter in a vertical orientation? Do you rig the litter differently with or without a litter attendant? Do you have a plan for how to transition the litter over an edge for a lower? What about a raise?
Horizontal vs. Vertical Rigging
Patients are never enthusiastic about being packaged and moved in a litter basket. Often, they’re in pain and just want it to go away. Lying horizontal is usually the most comfortable position–and a familiar one; it’s not uncommon for a patient to fall asleep while in the litter on an extended rescue operation. Hanging vertically in a litter, on the other hand, can be both terrifying and uncomfortable to an injured patient. However, there are times when vertical raising or lowering are the best and fastest options for patient movement. Narrow areas such as manholes or ladder enclosures necessitate a vertical orientation of the litter. Terrain and vegetation will also dictate the litter orientation in a wilderness environment.
Packaging Considerations
As with packaging in any litter configuration, when the time and materials are available, attempt to pad the patient in the appropriate places to prevent further injuries. There’s a difference in packaging a patient for short, horizontal movement vs. a multi-hour technical rescue. For technical rescue packaging and longer transports in the litter, pay attention to padding behind the knees, and between the litter and the patient’s legs, pelvis and shoulders. If the patient is to be raised or lowered in a vertical position, then they should be placed in the litter as close to the top rail as possible. Avoid having their feet contact the lower rail, as this will put pressure on their lower back and legs.
To ensure that the patient stays in place, they need to be appropriately lashed into the litter. This can be done using a combination of a harness and an internal lashing. Alternatively, tie a long piece of webbing in a wrap around the patient’s pelvic area with the ends of the webbing secured at the top of the litter. Practice this a few times so that the patient will not slide down due to slack in the rigging.
Rigging for Vertical
Most often, the litter is rigged with the standard horizontal rigging spider and the lower end elongated or disconnected, but it’s critical to practice vertical rigging ahead of time so you’ll know how your equipment works. Example: The litter spider will need to be long enough to ensure that the rigging will not end up lying across the patient’s face and will clear their head. This isn’t possible even in the longest position on some litter spiders, so check that out ahead of time.
If you’ve attached a patient safety strap from the main litter attachment point (rigging ring) or the tail of the main or belay line to the patient (which may not be needed) check that there’s enough slack in this connection so that the patient won’t be hanging from this connection when the litter spider gets weighted.
Many litter spiders connect to a steel rigging ring. At minimum, these rings are a half-inch and are rated to 10,000 lbs. The larger 9/16″ rings are rated to 40,000 lbs. Attaching the main and belay lines to these rings with a direct tie-in keeps the overall length of the rigging short and reduces the chance of an unlocked or tri-axle-loaded carabiner. When using a one-piece litter with the patient secured by internal and external lashing, your team can decide whether an additional attachment to the patient is needed.
The Spiders
Not all litter spiders are created equal. Commercially sold spiders may be made with strands of 12.5-mm rescue rope, 2″ mil spec. webbing or 1″ mil spec. webbing. Each of these has a different rating, with the 12.5-mm rope having the highest rating as well as significant abrasion resistance. You can also make your own litter spiders from material as small as 7-mm on up to 12.5-mm or even flat or tubular webbing. All of these have different strength ratings and resistance to abrasion.
When rigging for a horizontal configuration, the spider strength isn’t much of an issue because the load is shared on four (sometimes three) legs. When the load is shared on two legs and the two legs are tied into a single bite, however–as in vertical rigging–you’ll have a single strand around the rigging ring holding your load. If you’re using a length of 12.5-mm rope or an independently stitched webbing spider, that’s not an issue. When using a single bite of 1″ tubular webbing or a smaller-diameter rope, you may consider tying the spiders with independent bites to the litter ring. Your rigging system should allow for use with single- or two-person loads so that you have the option of using an attendant. Regardless of the spider rigging you use, you should evaluate it with a critical point systems analysis and a 10:1 static system safety factor analysis.
Getting Over the Edge
Whether on a lower or a raise, the edge is the most difficult portion of the evolution. At a glance, departing an edge with the litter in a vertical position appears to be easier because there’s more opportunity for edge tenders to manipulate the litter. But in fact, the process can be quite difficult as the patient is pushed out feet-first and then the edge tenders attempt to change the orientation of the litter from feet-first horizontal to feet-first vertical.
Navigating the edge on a vertical lower can be awkward; there’s often a “drop” as the mainline is loaded as the litter transitions over the edge. On a raise, it can be extremely difficult to change the direction of pull on the litter; it can end up stuck at the edge. In either case, it can be a back-wrenching job for the edge tenders. Whenever possible, we attempt to find a way to elevate the mainline. Without a high overhead anchor a vertical orientation of the litter may be easier to manage than a horizontal one but there’s still the issue of transitioning past the edge.
This is where the V Strap method can be helpful. The V Strap is a long, two-leg bridle attached to the litter when it’s vertically oriented and immediately below the edge transition. The bridle attachment point is on the sides of the litter, about two feet above the foot of the litter. The main and belay lines remain in position. The V Strap is a third rope, usually 8- or 9-mm cordelette, attached to the litter. It can be attached to a 2:1 or 3:1 mechanical advantage system without a progressive capture cam (PCD).
The V Strap technique can be used to negotiate an edge on both a raise and a lower. It doesn’t require any additional personnel; the haul team can run the V Strap and a single person can be left to pull the mainline though the PCD (on a raise) or run the lowering device (on a lower).
Regardless of whether you chose to use a V Strap, if a litter attendant is used, get them off the system prior to hauling the litter over the edge. If working on a lower do not put the litter attendant on the system until the litter is over the edge and the litter spider rigging has cleared the edge and is weighted.
Rigging Without an Attendant
If the patient does not require management while being raised or lowered and a tag line can keep the litter away from obstructions, consider rigging without an attendant. The load will be easier to lower and you will save on personnel. Rigging the main and belay lines to the litter rigging ring with a direct tie-in will save you hardware and reduce the total length of your rigging. I like to attach the main line to the ring with a bowline (backed up) because I can untie it when it’s unweighted. The belay line can be attached with either a figure eight follow through or a bowline (backed up).
Wrapping Up
So, what happened during the lower off the water tank? Due to some sloppy rigging, there was not quite enough length in the main line for the litter to reach the ground. A knot pass was performed and the litter reached the ground.
