Anesthesia Student Survival Guide.pdf - Index of

38 ● AnesthesiA student survivAl Guide
Slow respiratory rate may also indicate excessive opioid effect. In some cases,
careful titration of naloxone, an opioid antagonist, can be used to reverse
opioids. But care must be taken not to be overzealous with this drug. Sudden
reversal of deep narcosis can lead to hypertension and pain. Moreover, due
to its short duration of action, vigilance for return of opioid effects in the
PACU is essential.
If you conclude that isoflurane is responsible for the patient’s delayed
awakening, how will you proceed?
Isoflurane must be eliminated by exhalation. You can raise the fresh gas flow
of 100% oxygen to 10 L/min or more to ensure that the patient does not
rebreathe any isoflurane. Modest hyperventilation, or at least avoidance of
hypoventilation with the use of controlled ventilation or careful attention
to end-tidal CO 2 during hand ventilation, may increase the rate of elimination.
However, care must be taken not to hyperventilate to the point of
cerebral vasoconstriction, which may counteract any enhanced elimination
by reducing egress of drug from the brain. Beyond these maneuvers, only
time will terminate the action of isoflurane. In some cases, postoperative
ventilation in the PACU may be necessary.
Suggested Further Readings
Bryant, B, Knights, K and Salerno, E (2007), Pharmacology for health professionals,
Mosby, Sydney.
Murphy J. Clinical Pharmacokinetics, 3rd Edition. Published by the American
Society of Health-System Pharmacists, Bethesda, MD, 2005.