40: Approach to Edx Studies in the ICU

Question 1

What precedes critical illness polyneuropathy in most cases? What type of polyneuropathy is it?

Answer 1

Typically septic encephalopathy;

axonal sensorimotor polyneuropathy

Question 2

When is phrenic neuropathy seen?

Answer 2

Idiopathic (post-infectious or autoimmune);
neuralgic amyotrophy;
maybe complication of thoracic surgery

Question 3

Most common muscle disorder in the ICU? What is the usual cause?

Answer 3

Critical illness myopathy;

neuromuscular blocking agents in conjunction with IV steroids

Question 4

What can adult-onset acid maltase deficiency lead to from an ICU standpoint?

Answer 4

Respiratory insufficiency with respiratory and abdominal muscles compromised

Question 5

With excessive electrical noise, what can be done to mitigate this in the ICU?

Answer 5

Use coaxial cables; good skin prep; use of electrode gel; turn off devices if possible; don’t touch the metal bed

Question 6

What to be wary of if F response is not present?

Answer 6

AHC is susceptible to suprasegmental inhibitor influences

Question 7

Besides peripheral neuropathy, what are a couple illnesses that can lead to both low/absent motor and sensory responses?

Answer 7

Acute motor and sensory axonal neuropathy (AMSAN);

CMT type 2C (diaphragm, vocal cord, limb, intercostal muscles)

Question 8

Again, what can lead to decreased activation?

Answer 8

CNS disease, sedation, pain, poor cooperation

Question 9

In addition to myopathy, what can lead to SDSA MUAP’s in ICU setting?

Answer 9

Severe NMJ disorders

Question 10

One method to try and differentiate CIP and CIM?

Answer 10

Direct muscle stimulation;
comparison of direct muscle CMAP with nerve-evoked CMAP ratio;
if about 1, think CIM, but if near 0 think CIP

Question 11

What are a couple reasons why you wouldn’t perform a phrenic motor study?

Answer 11

With external pacemaker in place or central line on that side