Some patients remember paralysis after emergency tracheal intubation

Key takeaways:

• After undergoing intubation, 7.4% of patients remembered feeling paralysis.
• Patients had less awareness of paralysis if they had low levels of consciousness before the procedure.

Some patients who underwent emergency tracheal intubation remembered feeling paralysis, and having this experience was based on their consciousness level before the procedure, according to results published in CHEST.

“A considerable proportion of patients report being awake and not able to move during invasive mechanical ventilation in the ED and ICU, which was more likely when patients had near-normal levels of consciousness prior to intubation,” Brian E. Driver, MD, of the department of emergency medicine at Hennepin County Medical Center in Minneapolis, and colleagues wrote.

In a prospective observational study, Driver and colleagues evaluated 886 adults who underwent emergency tracheal intubation and received a neuromuscular blocking agent for the procedure to find out how common recalled awareness in paralysis is in these patients.

Researchers found the studied patients in a continuous quality improvement database that tracks many factors involved in intubation, as well as patient data. Through a modified Brice questionnaire, researchers evaluated patients’ remembrance during paralysis and/or memory of the breathing tube being placed after extubation in an interview between the physician and the patient.

This information was then presented to three physicians who determined if the patient’s experience of paralysis awareness and/or memory of intubation was definite, possible or not.

Of the total cohort, researchers concluded that 61 patients possibly recalled awareness, whereas five patients definitely did, making for a total of 66 patients (7.4%; 95% CI, 5.8-9.4). In terms of memory of the procedure, researchers concluded that 15 patients possibly have this memory, whereas 19 patients definitely did, for a total of 34 patients (3.8%; 95% CI, 2.7-5.3). Twenty-one patients experienced both outcomes.

Based on the Richmond Agitation Sedation Scale (RASS), researchers found that 14 out of 45 patients with just awareness of paralysis had a score of 0, signaling that they were alert and calm before the procedure, and 13 patients had a score of +1 or more, which signals that they were restless or agitated. The 18 remaining patients had lower levels of consciousness, with scores ranging from –1 to –5.

To figure out clinical variables related to awareness, researchers used a logistic regression model and found a relationship between a reduced likelihood of awareness and negative consciousness levels before being intubated (adjusted OR = 0.39; 95% CI, 0.22-0.69).

This was the only significant association found since researchers did not find any relationships between recalled paralysis awareness and the neuromuscular blocking agent (rocuronium vs. succinylcholine), sedative (ketamine vs. etomidate), shock index before intubation and sedatives given after intubation (ketamine or propofol).

Similarly, no variables were related to memory of the procedure in logistic regression models, according to researchers.

As another measure of memory, each patient was shown a picture of an apple before the procedure, and 39 remembered the image. A majority of these patients (92%) had a RASS score that signaled alertness or restlessness.

“Clinicians should ensure that effective sedation is given during neuromuscular blockade,” Driver and colleagues wrote.