Identify a Pacer by Chest X-Ray

Clinicians are confronted every day with a growing number pacemakers (PMs), implantable cardioverter-defibrillators (ICDs) and implantable loop recorders (ILRs). Collectively these devices are sub summarized as cardiac rhythm management devices (CRMDs). Identification of these devices is simple as long a the patient can present an ID card or some other form of identification. This can become challenging especially in emergencies where such information might not be accessible and interrogation of the pacemaker becomes a problem.
Using the wrong manufacturer-specific device programmer causes delay in diagnostic and treatment and can be relevant in these situations.

Techniques to identify a CRMD are following:

- Patient's ID card

- Medical records

- Manufacturers' patient registries (All CRMD manufacturers keep their own in-house registry of patients implanted with their devices and provide 24-hour telephone technical support

- Device specific radiopaque alphanumeric codes (ANC)

All these identification techniques have their problems in clinical practice and so far no other technique or algorithm was available to help out in such a dilemma. Sony Jacob et al. have therefor developed and validated the so called

Cardiac Rhythm Device Identification Algorithm using X-rays (CaRDIA-X, see below)

The study participants using this algorithm showed an overall accuracy of 96.9%. This study was published in 2011 but only now caught our attention.

We have tried this algorithm on a few X-rays ourselves and came to the conclusion:

Using the chart is a little challenge itself, but very helpful in most cases! Certainly worth keeping in mind!

Jacob S et al. Heart Rhythm. 2011 Jun;8(6):915-22.

CT is the Key to Clear the Spine in the Intoxicated!

We just had the discussion again and finally found a good and solid answer to it:

A 19 year old male was transferred to our unit from casualty with a GCS of 10 (E2, V3, M5) secondary to a little bit of... to many drinks. As he was found lying on the ground with no company an unwitnessed fall was considered and a rigid collar applied by paramedics. A c-spine CT-scan in the hospital showed no abnormalities and the patient was transferred to ICU for further treatment... with the rigid collar still in place!

The question soon arose whether it is safe to remove a rigid collar in the intoxicated and dazed patient after a normal c-spine scan or not. Some argued that the patient should also be examined clinically once sober in order to safely evaluate and clear the spine. As always by the way: The rigid collar was removed in ICU and no further problems evolved. 

At that time we just knew it is safe to do so but now we seem to get some excellent evidence supporting this procedure.

Martin et al. have just published a 

prospective multicenter study at 17 centers

in which they analyzed

10191 trauma patients that underwent CT of the c-spine during their primary evaluation (67% male, 83% car accidents or falls, mean ISS 11)

They found that 

the intoxicated cohort had a lower incidence of c-spine injuries

and that

c-spine CT had a sensitivity of 94%, a specifity of 99.5% and a negative predicitve value of 99.9%!
In words this means that a negative CT-result for a patient gives us a very high confidence that this negative result is true!

The Bottom Line:

Clearing the c-spine by CT-scan in the intoxicated patient is definitely safe, especially when there are no other injuries or history of a high velocity trauma.

Martin MJ et al. J Trauma Acute Care Surg. 2017 Jul 19

Intraoperative Ketamine: A Big Hooray for Special K?

Postoperative pain and delirium is a common concern and currently approached by different interventions. There is  some evidence suggesting that ketamine given intra-operatively might have an influence on postoperative pain and delirium. Some anaesthetists commonly give a single dose of ketamine intra-operatively for exactly this reason.

Thumbs up for Ket

Ketamine has kept its fascination in various settings, from retrieval medicine onto the the care of critically ill patients in the ICU.  Ketamine reduces postoperative markers of inflammation, is a rapid-acting antidepressant drug with an effect lasting for several days and might have neuroprotective properties. 

Ketamine also has become increasingly popular as an adjunct to other sedatives in the ICU. There is evidence showing that ketamine used in the ICU has the potential to reduce cumulative opioid consumption after surgery (Asad E. et al. J Intensive Care Med December 8 2015 ).

Even better: It does not cause any kidney injuries, preserves laryngeal protective reflexes, lower airway resistance and much more...

And: Ketamine is cheap and has been used safely for over 50 years by anaesthetists!

The Dark Side of Ket

But there's the other side of ketamine making all of this a little more complicated. After all, Ketamine is a psychoactive drug and has well known hallucinogenic properties. Developed in the 1960s as a dissociative anaesthetic agent it started to appear on the street in the early 1970s and made its way to the 1980s as Special K, Acid and Super C (Dotson JW et al. J of Drug Abuse, Vol 25, Issue 4, 1995).

From a medical point of view there are some worries that these psychotomimetic effects, which are of concern in the critically ill patient, might predispose to delirium (Erstad BL, J Crit Care, Oct 2016, Vol 35, p 145-149​).


On the background of all this facts this trial revealed some interesting findings. Avidan et al. performed a

multicentre, international randomised trial

in which they randomly assigned

672 patients undergoing major cardiac and non-cardiac surgery under general anaethesia

into three groups to either receive a bolus of

placebo (normal saline), low-dose ketamine (0·5 mg/kg), or high dose ketamine (1·0 mg/kg) after induction of anaesthesia, before surgical incision.

 Participants, clinicians, and investigators were blinded to group assignment. They found

NO difference in in the incidence of postoperative delirium among these groups


significantly more postoperative hallucinations and nightmares with increasing ketamine doses compared to placebo
This trial seems well performed with an acceptable sample size. The application of a single dose of ketamine before surgery neither prevented delirium nor induced it. With this sample size it seems safe to say that even if ketamine does prevent delirium, its effect would be rather small.

Furthermore, postoperative pain was not influenced by giving a single dose of ketamine and this is in contrast to previous findings and current guidelines. Importantly, most of the previous studies are smaller than this trial, making these findings remarkable.

But what really drew my attention was the fact that the appearance of hallucinations and night-mares was increased for at least 3 days after surgery.  

So if ketamine has no influence on postoperative delirium or pain but does induce hallucinations and nightmares, even 3 days after surgery, current guidelines might have to be revised.

The Bottom Line

- The application of a subanaesthetic dose of ketamine during surgery to tackle postoperative pain and delirium does not seem to be as effective as previously assumed

- The usage of ketamine in this setting even seems to have undesirable side-effects like hallucinations and nightmare - and this effect might even last for up to 3 days!

- This trial provides good reasons to look for other options to prevent postoperative delirium!

(Like dexmedetomidine? The answer to this question has just been answered: READ HERE!)