Case Study: Trench Rescue Near Miss

The information in this blog post comes from the FireFighterNearMiss.com.  To read the full near miss entry that was submitted, click here.

What Happened:

The fire department was dispatched to a trench collapse, with reports of two people trapped.  The first-arriving engine company arrived and spoke to “experts” that were on-scene at the construction site.  According to the experts, shoring was not required.  The engine company personnel entered the excavation and began working to free the only trapped individual (the other had self-extricated prior to their arrival).

When the battalion chief arrived on-scene, he/she established a command presence and ordered everyone out of the excavation.  Luckily, everyone was removed, apparently including the patient.  Moments later there was a secondary collapse of the remaining excavation wall.

11-24Source: IFSTA

Analysis:

Awareness level training is paramount!  According to NFPA 1670, emergency services organizations must identify hazards in their community.  If there is a chance their members will be dispatched to a technical rescue incident, the organization must at a minimum provide awareness level training to its members.  In this case study, the engine company personnel either did not have awareness level training, or their training was inadequate.  Luckily, the battalion chief was able to identify the hazard of a secondary collapse and evacuated the trench.

Any time there has been a collapse of an excavation or a trench wall, there is always the possibility of a secondary collapse.  How many times have you seen workers inside trenches with the trench boxes sitting outside of the trench (pictured above)?  While we sometimes must rely on “experts” that are on-scene, we must also realize that we are there for a reason.  Specifically, something has already gone wrong!  Often that something went wrong because the expert on-scene was either not educated on the hazard or chose to skip the appropriate safety measures needed to mitigate the hazard.  We must critically analyze the information provided to us when performing our size-up to ensure our members and the patient remain safe.

Please contact us if your emergency services organization needs Trench Rescue Awareness (3 hours) or any other awareness level training!

Bill Elder
Owner / Lead Instructor
Elder Technical Rescue Services, LLC

Tips for the Trench Rescue Professional

This week is Trench Safety Stand Down Week, sponsored by the National Utility Contractors Association (NUCA).  So far this week we have taught two of our Trench Rescue Awareness programs for first responders, and today we are sharing a new blog post focused towards our readers that are trained to the operations or technician level in trench rescue.  Our instructors are each sharing one tip with you related to trench rescue operations.

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Instructor Larry – Scene Control and Management

Trench rescue incidents can become worse by rushing in and causing greater damage to the victim.  There have been many cases of the “would-be rescuer syndrome” that afflicts the confined space field also occurring in the trench and excavation environment.  It is important that the first-arriving responder establish command and start to take control of the scene.  Remove would-be rescuers from the trench, shut down running equipment, and start to reduce risk by placing ladders and ground pads in and around the trench.

Instructor Bill – Shoring Operations

Remember the 2-4-2 rule of thumb.  Your top and bottom struts should be placed no more than 2 feet from the top and bottom of the trench wall.  There should also be no more than 4 feet between each strut.  When dealing with an 8 feet deep trench, two struts will theoretically be sufficient based on this rule.  However, consider using three struts even in an 8 feet deep trench for added safety, especially if operating in the recovery mode and not in rescue mode.  Do not risk a rescuer’s life to recover a dead body.

Instructor Rob – Equipment Retrieval

Once the patient is removed from the trench, rescue teams will typically want to retrieve their equipment, especially if they were using pneumatic struts for their shoring.  Take a deep breath after the extrication is complete, and mentally prepare for the removal of equipment from the trench.  If you used pneumatic struts to complete the rescue, your team may consider installing wood struts adjacent to them in order for the pneumatic struts to be removed safely.  No matter how you decide to handle the equipment retrieval, do not let your guard down, many hazards will still be present.

The Elder Technical Rescue Services, LLC Instructor Team

Safety Rules for Trench Rescue

OSHA 1926 Subpart P is the federal safety regulation that the construction industry must abide by when working in excavations.  While it may not apply to you as a first responder strictly from a regulatory perspective, there are many best practices related to trench and excavation safety that the emergency services field adopts from the OSHA regulation.  In this post, we will review some of these best practices.

Trench and Excavation Basics

An excavation is defined by OSHA as any man-made cut, cavity, trench, or depression in an earth surface, formed by earth removal.  A trench is merely a specific type of excavation that is narrow in relation to its length.  Trenches and excavations are dug every day in communities all around the United States.  They are dug to install, maintain, or repair things like building foundations, utilities, and underground storage containers.

Trench

The primary problem with working in trenches and excavations is having the walls of dirt collapse on a worker, seriously injuring or killing them.  In 2016, the number of deaths resulting from trench collapses outnumbered the total deaths from the previous two years.  The alarming rise in fatalities caught the attention of OSHA as well as the technical rescue community.

Best Practices

Means of Egress – A stairway, ladder, or ramp must always be within 25 feet laterally from a rescuer in any trench greater than 4 feet in depth.  Typically, first responders exceed this requirement during rescue operations by placing a minimum of two ground ladders in the trench.

Air Monitoring – Air monitoring for oxygen deficiency and other hazardous atmospheres must be conducted in any trench greater than 4 feet in depth prior to a rescuer entering the trench.  The monitoring must continue to ensure the atmosphere stays safe.  Typically, this results in a first responder being assigned to conduct continuous monitoring during a rescue.

Cave-In Protection – Rescuers must be protected from cave-in or collapse in every trench greater than 5 feet in depth.  Remember, if you respond to a trench collapse incident, there is a strong potential for a secondary soil collapse, so this protection is incredibly important.  Typically, first responders will protect a trench from collapse with shoring by using wood and/or aluminum struts.  This is an operations or technician level skill, depending on the depth and complexity of the trench collapse.

Daily Inspection – Per OSHA, a “competent person” must inspect trenches and excavations daily to detect evidence of cave-in, hazardous atmospheres, and other hazards.  For first responders, this translates into the need to appoint an Incident Safety Officer during rescue operations.  Be sure to appoint a safety officer who is knowledgeable in trench rescue operations!

Bill Elder
Owner / Lead Instructor
Elder Technical Rescue Services, LLC

Mention this blog post when contacting us to set up a Trench Rescue Awareness (3 hrs) class for your agency and receive a 10% discount!

Prehospital Treatment of Crush Syndrome

You and your partner are dispatched as the first due responding ALS unit for an industrial rescue. The dispatch notes indicate that one worker is trapped after an accident, but no other workers are injured. You see that you have a heavy rescue, a rescue-engine and ladder company responding with a chief officer. Enroute, you and your partner start discussing how you will approach the extrication and the medical treatments that may be necessary.

The scenario described above falls into the category of low frequency, high impact. Simply stated, they don’t happen all that often, but when they do, they are time and resource intensive. You may only have an annual refresher on technical rescue and the medical treatment of these types of patients. Lastly, with the low frequency of these events, we are not able to refine our skills through repetition on the job. With any technical rescue, the first consideration should be, “Is the scene safe?” You will need to consider what other resources you may need on scene such as a second or third ALS unit for other victims and the rescuers.

2-37Typical High-Pressure Air Bag Kit. Source: IFSTA

Arriving on scene you are directed to a staging area that will allow suitable egress from the incident. You find the victim conscious, alert and oriented with a patent airway. There is a large concrete pipe laying across the patient’s right femur. His chief complaint is leg pain, and he denies any other injuries. You attach your cardiac monitor and see that other than a slightly elevated normal sinus rhythm heart rate, all other vital signs are within normal limits. You establish two large bore IVs and follow your protocol for pain control with analgesia. By now the rescue company has determined that the best way to extricate the victim will be by using air bags to lift the pipe. The patient’s right leg has been pinned by the concrete pipe for 45 minutes. The rescue company say that they are ready to lift and are waiting for you to give the go ahead. Coordinated extrication is key in the removal of any victim, but with crush syndrome it is paramount due to the type of injury.

Crush injuries differ from other types of blunt force trauma. After as little as thirty minutes, the damage to large muscle groups will have a profound effect on your patient. When cells are crushed the cell membrane is compromised, and everything inside the cell is suddenly let out. The inflicting object, in this case a concrete pipe, prevents the spilling out of these harmful contents until it is removed or lifted from the muscle. You will be most concerned about the sudden release of potassium into the patient’s blood stream. Continuous ECG monitoring is key as you will be watching for ECG changes to determine the presence of excess potassium, known as hyperkalemia. The progression of changes during hyperkalemia will go from peaked T waves, to ST depression / prolonged PR intervals and eventually to a wide QRS / V-tach which is life threatening.

IMG_3684Sodium bicarbonate is a key medication used for treating crush syndrome. Calcium chloride and albuterol are other medications used.

We treat hyperkalemia with an array of medicines each carrying out a separate task. The first is by introducing a chemical buffer to offset the impending acidosis. This is achieved by pushing sodium bicarbonate. The timing of this administration is key. It must be done when the object is lifted and the sudden release of potassium hits the bloodstream. Secondly, we want to protect the myocardium which is especially sensitive to potassium by administering calcium chloride. This will precipitate if mixed with sodium bicarbonate, so use your second IV to accomplish this. Lastly, an albuterol treatment can be applied as it will help to drive potassium out of the bloodstream and back into uninjured cells. As soon as the victim is extricated be prepared to open your IV fluids wide open to obtain a systolic blood pressure greater than 100 and to give additional sodium bicarbonate and calcium chloride if ECG changes are observed. The patient should be promptly packaged and transferred to the nearest trauma center.

The key to the successful treatment of crush syndrome involves the coordination of all parties involved. You should not hesitate to call for additional resources such as another ALS unit or for a physician response team that may carry additional medication outside of your ALS protocol. As with any incident, scene safety and communication is key. Let your patient know what you’re doing and when you’ll be doing it. While time is of the essence, don’t rush through the extrication as not coordinating the administration of medication with the rescue company can have life-threatening effects. A rescue like this may be a once-in-a-career event, but your patient will be depending on your expertise to save them.

Author’s note: Always refer to your medical director and local protocols for clinical guidelines in your jurisdiction.

Larry Durland, BSN, RN, PHRN, CFRN, CEN
Instructor
Elder Technical Rescue Services, LLC

Mention this blog post when contacting us to set up a Medical Aspects of Technical Rescue (3 hrs) class for your agency and receive a 10% discount!

Picking Things Up with Cribbing and Air Bags

Heavy lifting drills can be an absolute blast for rescue professionals.  There is something extremely satisfying about lifting an object of considerable weight with the simple press of a button.  However, there is a lot of knowledge, skill, and attention to detail that goes into these evolutions.

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Box Cribbing

Do you know how much weight your box cribbing can safely carry?  Typical 4″ x 4″ cribbing made of softwoods (i.e., Douglas Fir) will provide you 6,000 lbs. of carrying capacity per contact point.  That means, when you stack two pieces of cribbing per layer, you have a total of four contact points for 24,000 lbs. of carrying capacity.  The maximum height of a crib stack is relative to the length of the pieces of cribbing, but the recommended maximum height of a crib stack made of 4″ x 4″ cribbing is 4 feet.

It is critical that all layers of the crib stack are aligned perfectly.  The transfer of weight through the crib stack is dependent on all of the connection points being in line.  If one of the layers of the crib stack is off centered, the entire operation can be compromised.  It is also important to maintain at least 4″ of overhang on the edges of the crib stack.  Finally, when lifting with high pressure air bags on top of a crib stack, the top layer of cribbing has to be a solid layer or else inflating the air bags will cause the entire stack to fail.

High Pressure Air Bags

The high pressure air bags pictured here are operated at 118 psi, but you have to be familiar with the correct operating pressure of your bags.  Some newer models operate at higher pressures.  Try to use the biggest air bag you have for your lifting evolutions to ensure you get maximum lift height and capacity.  Remember, as the bag inflates, its lifting capacity decreases due to the bag’s shape becoming rounder.

A maximum of two bags can be stacked (again, this can differ between makes and models), and when that is done the lifting capacity is equal to that of the weakest air bag.  We recommend always stacking two bags if you have the space, even if you don’t think you will need to use both of them.  It slows the whole rescue scene down when you realize one air bag isn’t giving you enough lift height and you have to scramble to add a second bag in after the fact.

Scene Management

It is important to remember that stabilizing and lifting are two different operations.  The priority is stabilizing the object to prevent the load from shifting and making the situation worse.  Then, we can set up our lifting operation.  When we lift, we always follow the object up with our stabilization system.  We refer to this concept as, “lift an inch, crib an inch.”

Assign a supervisor to oversee both the stabilization and lifting operations to ensure they are on the same page and coordinating their efforts.  The supervisor should also give all lifting commands.  A safety officer is also an important position to fill during these evolutions.  Keep the number of personnel near the object during the lifting operation to the bare minimum (typically just those adjusting the stabilization system).  For those who must remain close to the object during the lift, ensure they are wearing appropriate PPE and always have an “exit strategy” should they need to remove themselves from a dangerous situation.

Lastly, you must coordinate the lifting operation with EMS!  Crush syndrome treatment has to begin before the lift and its imperative EMS is ready to provide follow-up treatment as soon as the patient is extricated.  We’ll talk about this more in our next blog post.

Bill Elder
Owner / Lead Instructor
Elder Technical Rescue Services, LLC