Newly Published
Correspondence  |   August 2019
Neurologic Examination for Anesthesiologists: Reply
Author Notes
  • Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Massachusetts Institute of Technology, Cambridge, Massachusetts. enb@neurostat.mit.edu
  • (Accepted for publication July 11, 2019.)
    (Accepted for publication July 11, 2019.)×
Article Information
Correspondence
Correspondence   |   August 2019
Neurologic Examination for Anesthesiologists: Reply
Anesthesiology Newly Published on August 19, 2019. doi:10.1097/ALN.0000000000002913
Anesthesiology Newly Published on August 19, 2019. doi:10.1097/ALN.0000000000002913
Professor Drummond makes a good point that apnea induced by propofol does not occur entirely through its actions at γ-aminobutyric acid–mediated synapses in the dorsal and ventral respiratory groups in the medulla and pons. However, he further writes, “I suggest that loss of consciousness mediated by suppression of the arousal centers, which is also considered by Reshef et al.,1  to be a more likely cause of apnea in these circumstances. In conscious subjects, respiration is generally sustained not by chemosensor stimulation, but by consciousness itself…After a bolus of  IV agent, loss of consciousness often causes apnea, because there is, for a short time, no alternative stimulus to provide respiratory drive.” These statements do not offer any specific circuit mechanism as to how loss of consciousness “causes” apnea.