Category Archives: Equipment

How To Measure Your Trauma Bay

In my last post, I detailed some standard info on trauma bay size. Today, I’ll describe what I found when I brought in my trusty tape measure a few years ago to check out the old trauma bays at Regions Hospital. I came up with several helpful measurements to help gauge the relative utility of the rooms.

Here are the indices that I came up with:

  • TBTA: Trauma Bay Total Area. This is the total square footage (meterage?) measured wall to wall.
  • TBWA: Trauma Bay Working Area. This is the area that excludes equipment carts next to a wall, and areas under countertops that extend away from the wall.
  • TBAA: Trauma Bay Available Area. This is the TBWA less any other unusable areas in the room. We have an equipment post near one corner that eats up 16.5  sq ft of space. Also remember to subtract the area taken up by the patient bed, as this area is not available to the trauma team, either.
  • TBSI: Trauma Bay Space Index. This value is derived by dividing the TBAA by the number of team members in the room. It gives an indication of how much space is available for each trauma team member to work in.

Values in the old trauma bays at my trauma center:

  • TBTA: 291 sq ft
  • TBWA: 220.5 sq ft
  • TBAA: 186.5 sq ft
  • TBSI: 15.5

What does it all mean? You’ll have to work out the details using measurements from your own resuscitation room. For my old rooms, it meant we each had a 4×4 foot square to move around in, on average. This was fairly tight, I would say. Fortunately, we’ve moved to new rooms with much, much more space.

Tune in to my next post this week on my thoughts on outfitting your resuscitation room.

Print Friendly, PDF & Email

How Big Should Your Trauma Bay Be?

Trauma professionals are never satisfied with the size of their trauma bay. Today, I’ll write about optimal trauma bay size. Next week, I’ll describe my system for quantifying the space in your trauma bay and address the equipment layout in your resuscitation room.

Trauma resuscitation rooms vary tremendously. They can range from very spacious…

to very tight…

Most trauma bays that I have visited were somewhere between 225 and 300 square feet (21-28 sq meters), although some were quite large (Rashid Hospital in Dubai at nearly 50 sq meters!).

Interestingly, I did manage to find a set of published guidelines on this topic. The Facility Guidelines Institute (FGI) develops detailed recommendations for the design of a variety of healthcare facilities. Here are their guidelines for adult trauma bays:

  • Single patient room: The clear floor area should be 250 sq ft (23 sq m), with a minimum clearance of 5 feet on all sides of the patient stretcher.
  • Multiple patient room: The clear floor area should be 200 sq ft (18.5 sq m) with curtains separating patient areas. Minimum clearance of 5 feet on all sides of the patient stretcher should be maintained.

The FGI “clear floor area” corresponds to my “Trauma Bay Working Area”, which is the area that excludes all the carts, cabinets, and countertops scattered about the usual trauma room. California’s guideline of 280 sq feet seems pretty reasonable as the “Trauma Bay Total Area”, if you can keep your wasted space down to about 30 sq feet.

Bottom line: Once again, don’t try to figure out everything from scratch if you are designing new resuscitation rooms. Somebody has probably already done it (designed a trauma bay, developed a practice guideline, etc). But remember, a generic guideline or even one developed for a specific institution may not completely fit your situation. In this case, the FGI guidelines say nothing about the trauma team size, which is a critical factor in space planning. Use the work of others as a springboard to jump start your own efforts at solving the problem.

Related link:

Print Friendly, PDF & Email

The Lowly Blood Pressure Cuff: Is It Accurate?

Yesterday, I described how the typical automated oscillometric blood pressure cuff works. We rely on this workhorse piece of equipment for nearly all pressure determinations outside of the intensive care unit. So the obvious question is, “is it accurate?”

Interestingly, there are not very many good papers that have ever looked at this! However, this simple question was addressed by a group at Harvard back in 2013. This study utilized an extensive ICU database from 7 ICUs at the Beth Israel Deaconess Medical Center. Seven years of data were analyzed, including minute by minute blood pressure readings in patients with both automated cuffs and indwelling arterial lines. Arterial line pressures were considered to be the “gold standard.”

Here are the factoids:

  • Over 27,000 pairs of simultaneously recorded cuff and arterial line measurements from 852 patients were analyzed
  • The cuff underestimated art line SBP for pressures at or above 95 torr
  • The cuff overestimated SBO for pressures below 95 torr (!)
  • Patients in profound shock (SBP < 60) had a cuff reading 10 torr higher
  • Mean arterial pressure was reasonably accurate in hypotensive patients

sbp-cuff-v-aline

Bottom line: The good, old-fashioned automated blood pressure cuff is fine for patients with normal pressures or better. In fact, it tends to understimate the SBP the higher it is, which is fine. However, it overestimates the SBP in hypotensive patients. This can be dangerous! 

You may look at that SBP of 90 and say to yourself, “that’s not too bad.” But really it might be 80. Would that change your mind? Don’t get suckered into thinking that this mainstay of medical care is perfect! And consider peeking at the mean arterial pressure from time to time. That may give you a more accurate picture of where the patient really is from a pressure standpoint.

Reference: Methods of blood pressure measurement in the ICU. Crit Care Med Journal, 41(1): 34-40, 2013.

 

Print Friendly, PDF & Email

How Does It Work? The Lowly Blood Pressure Cuff

The blood pressure cuff is one of those devices trauma professionals don’t give a second thought to. Old timers like me remember using the cuff with a sphygmomanometer and stethoscope to get manual blood pressures. I’ve had to do this twice in recent months on airplanes, and I had forgotten how much work this is.

But technology makes things easier for us. Now you just slap a cuff on the arm (or wrist), push a button, and voila! You’ve got the pressure.

But have you stopped to think about how this actually works? Why don’t we need the stethoscope any more? Here’s the scoop:

When you take a manual blood pressure, the cuff is inflated until a pulse can no longer be auscultated with the stethoscope. The pressure is slowly released using a little thumb wheel while listening for the pulse again. The pressure at which it is first audible is the systolic, and the pressure at which it softens and fades away is the diastolic.

The automatic blood pressure device consists of a cuff, tubing that connects it to the monitor, a pressure transducer in line with the tubing, a mini air pump, and a small computer. The transducer replaces the analog pressure gauge, and the pump and computer replace the human.

The transducer can “see” through the tubing and into the cuff. It is very sensitive to pressure and pressure changes. The computer directs the pump to inflate to about 20 torr above the point where pulsations in the air column cease. It then releases the pressure at about 4 torr per second, “feeling” for air column vibrations to start. When this occurs, the systolic pressure is recorded. Deflation continues until the vibrations stop, representing the diastolic pressure. Each manufacturer uses its own algorithm for this, adding or subtracting a few torr to obtain the most accurate reading for their particular device.

bpcuff

Piece of cake! But here’s the question: is it accurate? In my next post, I’ll write about how the automated cuff compares to an indwelling arterial line.

Print Friendly, PDF & Email

The Rise And Fall Of MAST Trousers

Remember MAST Trousers (Military Anti-Shock Trousers)? They were a staple of prehospital care starting in the 1970s and lasting through the turn of the century. But what happened after that? They seem to have disappeared. I recently received a question on the topic recently and wanted to share the real story with you readers.

The basic MAST trouser consists of three inflatable compartments: two legs and one covering the abdomen and pelvis. Each can be inflated or deflated separately. The basic concept was first described by a surgeon who wanted to increase blood pressure during neurosurgical procedures in the early 1900s. The US military embraced the concept during the Vietnam war, using it to augment systolic pressure in servicemen in shock.

Military surgeons migrated this device into civilian prehospital care during the mid-1970s, and the American College of Surgeons Committee on Trauma listed this device as essential on all ambulances in 1977. MAST trousers then came into widespread use throughout the 1980s and 1990s.

Early research in the 1970s suggested that this device could provide up to a 20% boost in volume to the upper part of the body when applied. But as occurs with so many new toys, additional research demonstrated that this auto-transfusion effect was actually only about 5% of blood volume. Some significant complications also came to light as lower extremity ischemia and compartment syndromes were described. Ben Taub Hospital published a study in 1987 which showed no improvement in mortality in patients with penetrating injury.

At the end of the century, support for MAST started to dry up. The NAEMSP published a position paper limiting use to ruptured abdominal aortic aneurysms and pelvic fractures with hypotension. The final straw was a review by the Cochrane Collaboration in 2000 that confirmed no reduction in mortality with MAST use.

Although a few older textbooks may still mention MAST trousers, they are no longer the standard of care. There are no longer any accepted indications for their use, and the few trousers that remain are gathering cobwebs in some corner of the trauma basement.

Reference: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan.

Print Friendly, PDF & Email