Category Archives: Equipment

What Is A Hybrid OR, Exactly?

A hybrid operating room is a special suite that allows advanced imaging to be carried out at the same time as one or more additional operative procedures. It’s that simple. It contains specialized imaging equipment including fluoroscopy and infusion equipment for radiographic dye administration. Some also contain CT and/or MRI capabilities, although the shielding required for these makes them very rare. It is generally stocked with a variety of endovascular

devices and supplies. The usual anesthesia circuits are available, as are selected surgical packs, typically related to vascular and CV surgery.

These suites are typically large, and can easily accommodate multiple operating teams. However, they are very expensive in a number of ways.

First, they take up a great deal of space. Many have the square footage of two or more standard operating rooms. Initial construction costs are very high, as are remodeling and maintenance costs. They can also tax the hospital engineering infrastructure, from electrical to plumbing to ventilation.

But if a hybrid room is available, it can deliver significant benefits to the hospital and to patient care. Intraoperative imaging can provide immediate quality assurance, and patients can undergo more complex procedures and enjoy a shorter length of stay.

Next post, why use a hybrid room for trauma?

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The Hybrid OR, Revisited

Over a year ago I published a series on using the hybrid room for trauma cases. In the meantime, some new papers have been published on this concept. Over the next two weeks, I’ll be refreshing and republishing this information to help you optimize the use of yours, or to support your efforts to get one if you don’t.

While quite a bit of trauma care is routine, involving simpler, single system injuries, a small subset of our patients sustains major, multi-system, and life-threatening ones. They require rapid access to skilled trauma professionals and advanced resources including imaging, operating rooms, and other procedures.

In most trauma centers, initial resuscitation takes place in a trauma resuscitation room in or near the ED. Some diagnostic imaging can be performed there, but more sophisticated studies may require a short (or longer) road trip. Operating rooms and other procedural areas are also usually more distant. And most importantly, each of these areas is designed for a single discipline. Diagnostic radiology has equipment, technicians, and radiologists available. Interventional radiology contains the specialized equipment needed for this more invasive procedure. ORs are designed specifically for surgical procedures, and frequently contain equipment for a single surgical discipline.

But some of our patients require it all! Think about a patient who arrives after a major car crash. Blood pressures are soft, the pelvis is grossly unstable, FAST exam is positive, and there is bleeding from the vagina.

How do we prioritize? Where do we go first? How long will it take the interventional radiology team to arrive? Where’s that external fixator equipment? Can we slip in a CT scan? Where’s OB/GYN??

The solution is right under our nose! Many hospitals have added so-called “hybrid ORs” to their operating suites in order to address the needs of their vascular and cardiovascular surgeons. The next several posts will cover everything you need to know about this important tool for trauma care. I’ll review:

  • What is a hybrid OR, exactly?
  • Why use a hybrid OR for trauma?
  • Is the hybrid OR for trauma useful?
  • Which patients may benefit from a hybrid OR?
  • So you want your own hybrid room?!

Next post: what is a hybrid OR, exactly?

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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.

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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 the past few years 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, or finger), 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. Using a manufacturer specific computer algorithm, the mean arterial pressure is measured. A little more proprietary calculation results in an estimated systolic and diastolic pressure.

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.

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EAST Guidelines: TEG And ROTEM In Coagulopathic Trauma Patients

In my last post, I explained why TEG is not so easy to use. Today, I’ll share the new Eastern Association for the Surgery of Trauma (EAST) practice management guidelines for using TEG and its twin, ROTEM for bleeding patients.

TEG first appeared in the trauma literature in 2008. A paper by John Holcomb showed that it was superior to the standard lab tests (PT, aPTT, and activated clotting time) in monitoring hemorrhagic shock in pigs. Since then, research has exploded with TEG papers. There have been about 50 published annually for the last four years.

In this month’s Journal of Trauma, EAST published their most recent practice management guideline, dedicating it to TEG. They identified over 6,000 potential papers and ultimately settled on 38 articles. They used them to attempt to answer three questions regarding use of these devices during resuscitation.

Question 1

In adult trauma patients with ongoing hemorrhage, should TEG/ROTEM be used vs non-TEG/ROTEM monitoring to guide transfusion strategy in order to reduce mortality, blood product transfusions and the need for additional hemostatic interventions such as angioembolization, endoscopy, or operation?

Answer: Only seven studies were found regarding this question. All but one showed no difference in 24 hour and hospital mortality. They also showed an inconsistent effect on blood product usage with some showing no difference and some shower less transfused product.

Nonetheless, EAST “conditionally recommended” the use of TEG/ROTEM. This is based  solely on the presumption that it can reduce the risk of blood transfusions by using a test that is harmless.

Question 2

In adult surgery patients with ongoing hemorrhage, should TEG/ROTEM be used vs non-TEG/ROTEM monitoring to guide transfusion strategy in order to reduce mortality, blood product transfusions and the need for additional hemostatic interventions such as angioembolization, endoscopy, or operation? Note the shift here to non-trauma patients.

Twenty one studies were found addressing this question. Most papers showed no difference in reoperation rate. There were also no consistent differences in transfusion of various blood products. And the vast majority showed no difference in mortality.

But once again, EAST conditionally recommended the use of this test in these patients, mainly because it is believed to be harmless.

Question 3

In adult critically ill patients with ongoing hemorrhage, should TEG/ROTEM be used vs non-TEG/ROTEM monitoring to guide transfusion strategy in order to reduce mortality, blood product transfusions and the need for additional hemostatic interventions such as angioembolization, endoscopy, or operation?

There were only 10 studies relating to this question, and they included patients with a variety of surgical and medical problems. TEG/ROTEM was no better than non-TEG parameters in predicting the need to transfuse, but did somewhat better than clinical judgement. Once again, there was no consistent effect on the number of transfusions given, although some studies showed that use of non-TEG/ROTEM studies resulted in fewer units of red cells, platelets, and cryoprecipitate given.

Interestingly, although there was little difference in the number of units transfused, fewer patients required transfusion using TEG/ROTEM. There was no difference in mortality or interventions to stop bleeding.

Yet again, EAST conditionally recommended use of TEG/ROTEM in these patients despite the very low level of evidence. Again, this is mainly because of the lack of perceived harm in using it, and the possibility that it might reduce exposure to blood products.

Bottom line: Hmm. I remain skeptical. What EAST is saying is that, hey it’s harmless and there’s a chance that it might reduce a patient’s exposure to blood products, so why not? I have a vial of bat wings and eye of newt that might do the same thing. As long as it’s harmless, right?

Well, it may be clinically harmless, but it costs money and time. First, you have to buy the machine. Luckily, they are much cheaper than a CT scanner. But then the manufacturer kills you with the disposables. Like a cheap inkjet printer, you have to keep buying $40 ink cartridges every few weeks to keep it working. Except TEG cartridges cost more than $40.

And don’t overlook the time spent training people in how to interpret the curves. And developing a system to obtain the specimen and pay people to run the equipment. It all adds up, and yet the papers can’t show us any dramatic clinical results.

I’ll probably irritate the TEG/ROTEM true believers, but it still seems like a device searching for a great clinical problem to solve. IMHO we need much more high-quality research to help us figure out how this tool can help us with our trauma / surgical / critical care patients.

Reference: Thromboelastography and rotational thromboelastometry in bleeding patients with coagulopathy: Practice management guideline from the Eastern Association for the Surgery of Trauma. J Trauma 89(6):999-1017, 2020.

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