As some of you remembered, I have recently changed my job to a university academic center where I have picked up a few new tricks and some new understandings of the effects of common drugs we use. I would love to share one of my favorites with you. I am in love with no narcotics induction because it provides more hemodynamics stability particularly in sicker patients with kidney transplant patients. Let me explain to you why I like no narcotics induction.
When I first worked at my new job, I was assigned to some kidney transplant patients. I would give 50-100mcg fentanyl at induction to the ESRD r/t DM1 patients who are in their late 20′-early 30′. They are otherwise no other significant medical histories. Throughout the surgeries, the BP would be on the soft side. This would not be ideal for the kidney transplant case. In the end, more fluid was given and dobutamine infusion may be needed as well. Surgeon was not happy! After my first two cases of kidney transplant, I stopped using fentanyl for my induction, instead I used esmolol for induction. Hemodynamically, it was very smooth during induction. Rarely I would have to use pressors during the prepping period. I noticed that with the same surgeon, similar patients’ comorbidities, BP was much more stable even for the older patients.
You may ask fentanyl should have minimal effects on hemodynamics and therefore it is a good choice of drug to give to kidney patients. First of all, ESRD patients have sympathetic over-activity when they are awake, hence hypertension is often observed. Their arteries are stiff due to the deposits of calcium over time with the failed kidney. You can see why patients become hypotension when sympathetic stimulation is removed after induction, especially with fentanyl given at induction. Secondly, fentanyl takes 5-10 minutes to peak depending on patient’s co-morbidities. How often do we give patient fentanyl 5-10minutes prior to induction? You see my point? That’s why you see increased HR and BP if you don’t give adequate dose of propofol. However, the bolus of fentanyl peaks after induction during prepping patient. That’s when patient becomes hypotension as sympathetic tone is further attenuated by the fentanyl. The duration of action of fentanyl is 30-90 minutes. Studies have shown that essentially all opioids have some degree of accumulation of active drug or metabolite in CKD and ESRD, hence, the 100mcg of fentanyl may linger a lot longer than normal healthy patients.
What did I use for induction you may ask? Esmolol! The purpose of fentanyl is to attenuate the sympathetic response to the tracheal intubation. As stated above, it has to be given at least 5 minutes prior to induction. For older patients, it may take longer time to reach the peak. It is unlikely that we would give patient bolus of fentanyl without monitoring. Neither is possible to sit around for 5 minutes to let it reach peak before you intubate. Esmololol is a much better choice in these scenarios as it attenuates sympathetic response but also has short duration. Hence, for patients who need longer prepping time (a big case or if you are at academic center), esmolol would provide much more stable hemodynamics than the bolus of fentanyl.
Please let me know what your thoughts are on this topics.