I’m always looking for ways to improve myself. Lately, I’m looking at various clinical elements of my practice and select certain endpoints that will better my practice of medicine.
This time, I’ve focused on cutting back on opioids intraoperatively for pain. I’m looking specifically at ketamine, an old drug with multiple benefits (and some downsides). Not only does ketamine help with intraoperative pain, but it also helps with postoperative pain. I’d like to incorporate some type of ERAS model for all of my patients and surgeries.
Ketamine: (different doses I’ve seen in the literature below)
• Induction: 0.2-0.5 mg/kg
• Infusion: 0.1mg/kg/hr before incision
◦ 2mcg/kg/hr x 24hr (spine)
◦ 0.1-0.15mg/kg/hr x 24-72hrs (UW)
What I’m using nowadays:
Cardiac open hearts: induction bolus=0.5mg/kg + infusion=0.1mg/kg/hr and stopping when last stitch placed. Patients seem to require less postoperative narcotics. Looking at time to extubation to see if this is improved. Time to extubation seems the same as my prior non-ketamine patients because RT and RNs follow a weaning protocol. Patients are more comfortable and require less pain medication.
Cardiac open hearts: induction bolus = 0.5 mg/kg + another 0.5 mg/kg bolus when re-warming; infusion 0.2 mg/kg/hr stopping when last dressing placed.
Cardiac open hearts: induction bolus = 1 mg/kg + 0.5mg/kg bolus pre-CPB. No infusion. This formula is roughly in between the bolus (0.5mg/kg) + infusion (0.1mg/kg/hr and 0.2mg/kg/hr) for <5hr case. For hearts >5hr, add 0.25-0.5mg/kg bolus when re-warming (0.5mg/kg dosing roughly approximates a 7hr case).
Cardiac open hearts: No induction bolus. 1mg/kg bolus prior to incision. 0.5mg/kg bolus pre-CPB. 0.25-0.5mg/kg bolus rewarming on CPB based on length of case (see July 2019 notes).
Question 1: Which patients and acute pain conditions should be considered for ketamine treatment? Conclusion: For patients undergoing painful surgery, subanesthetic ketamine infusions should be considered. Ketamine also may be warranted for opioid-dependent or opioid-tolerant patients undergoing surgery, or with acute or chronic sickle cell pain. For patients with sleep apnea, ketamine may be appropriate as an adjunct to limit opioid use.
Question 2: What dose range is considered subanesthetic, and does the evidence support dosing in this range for acute pain? Conclusion: Ketamine bolus doses should not exceed 0.35 mg/kg, whereas infusions for acute pain generally should not exceed 1 mg/kg per hour in settings lacking intensive monitoring. However, dosing outside this range may be indicated because of an individual patient’s pharmacokinetic and pharmacodynamic factors and other considerations, such as prior ketamine exposure. However, ketamine’s adverse effects prevent some patients from tolerating higher doses for acute pain; therefore, unlike for chronic pain management, lower doses in the range of 0.1 to 0.5 mg/kg per hour may be necessary to achieve an acceptable balance between analgesia and adverse events.
Question 3: What is the evidence to support ketamine infusions as an adjunct to opioids and other analgesic therapies for perioperative analgesia? Conclusion: There is moderate evidence to support using subanesthetic IV ketamine bolus doses up to 0.35 mg/kg and infusions up to 1 mg/kg per hour as adjuncts to opioids for perioperative analgesia.
Question 4: What are the contraindications to ketamine infusions in the setting of acute pain management, and do they differ from chronic pain settings? Conclusion: Patients with poorly controlled cardiovascular disease or who are pregnant or have active psychosis should avoid ketamine. Similarly, for hepatic dysfunction, patients with severe disease, such as cirrhosis, should not take the medicine; however, ketamine can be given with caution for moderate disease by monitoring liver function tests before infusion and during infusions in surveillance of elevations. On the other hand, ketamine should not be given to patients with elevated intracranial pressure or elevated intraocular pressure.
Question 5: What is the evidence to support nonparenteral ketamine for acute pain management? Conclusion: Intranasal ketamine is beneficial for acute pain management by achieving effective analgesia and amnesia/procedural sedation. Patients for whom IV access is difficult and in children undergoing procedures are likely candidates. But for oral ketamine, the evidence is less convincing, although anecdotal reports suggest this route may provide short-term advantages in some patients with acute pain.
Question 6: Does any evidence support IV ketamine patient-controlled analgesia (PCA) for acute pain? Conclusion: The evidence is limited to support IV ketamine PCA as the sole analgesic for acute or periprocedural pain. There is moderate evidence, however, to support the addition of ketamine to an opioid-based IV PCA regimen for acute and perioperative pain therapy.
Ketamine is an N-methyl-d-aspartate receptor antagonist that is commonly used as an adjunct for the treatment of acute postoperative or posttraumatic pain to improve pain scores and reduce opioid consumption by approximately 30-50%. Certain patients seem to benefit more from the addition of ketamine, including those with chronic neuropathic pain, opioid dependence or tolerance and acute hyperalgesia. 8% of administered ketamine is metabolized by the liver forming norketamine, which possess only 20-30% of the potency of ketamine. Norketamine is then hydroxylated into a water-soluble metabolite excreted by the kidney. Most clinicians believe that dose modification for ketamine is not required for patients with decreased renal function.[48,49
A little background info… I’m an anesthesiologist for a fairly busy practice. That means we get called when you need an epidural or c-section. I am currently in my first pregnancy (so I haven’t experienced my own birth process), however I’ve seen and managed thousands of epidurals for delivery.
One of the most important things moms can do for their pregnancies… Eat right (clean, get plenty of veggies and fruits) and exercise. This is the best prep work you can do! Secondly, have an open mind when selecting your birth plan. You are not in control of what will happen. What happens with your baby is what will dictate what you will need and what will be best for your baby. Many mothers have opted for a “natural” delivery and have been successful. Some mothers have been in a fully equipped medical center and have had bad outcomes unrelated to interventions for their baby.
Your goal as a mom is to guide and give direction to your delivery team of your wishes — but this is a process that changes throughout your labor so flexibility is key.
Epidurals are NOT harmful for your baby. There are multiple studies that’re well backed with huge sample sizes that prove this. Epidurals can slow certain stages of labor, but it’s NOT harmful to you or your baby. There are a lot of misconceptions about epidurals. Whether it’s patient experience, epidural effectiveness (and this can be patient controlled), or fear of the unknown… epidurals have been given a bad reputation and sometimes these traumatic experiences are passed down without rhyme or reason (similar to the anti-vaccine movement which is dangerous!).
So, pick a birth plan… be flexible with it. Do what you can to optimize your health (and birthing experience) via diet and exercise. Lastly, no one loses when they’re comfortable. Comfort leads to a good experience and overall a happy mom, baby, and family.
Here’s my plan (which isn’t for everyone):
1) more plant-based diet w some fish
2) exercise via walks, hikes, and pilates/yoga/barre
3) birth plan: vaginal delivery with minimal pain (epidural immediately: I don’t want to feel a thing)… but anything to get the baby out safely.
4) breastfeed like crazy if possible
5) go back to work after 3 months
6) breast milk for at least 6 months (but will try for a year)
My plan isn’t for everyone… it’s for me. Good luck!!
Infusion: 2-3mg/kg/hr after induction to end surgery
If cardiac on CPB: bolus 1.5mg/kg on induction; Infusion: 4 mg/min x 48 hrs or discharge from ICU; On CPB bolus 4 mg/kg.
I am currently not using lidocaine infusions as my open heart patients are getting great relief with ketamine. I also came across some literature that said lidocaine infusions do not help postoperative cognitive decline. However, I may reassess this at a later time and reinstitute. We do not currently have an acute pain service. Look at the ASRA, May 2017 issue, I do like the dosing regimen used at UVA. See below.
In our institution, an infusion rate of 40 mcg/kg/min after 1–1.5 mg/kg bolus is used perioperatively as part of our ERAS protocols. The infusion rate is decreased to 5–10 mcg/kg/min at the end of the surgery and continues at the same rate until POD 2. Our acute pain management lidocaine infusion protocol uses a 0.5 mg/min starting dose with a maximum of 1 mg/min for adults, and doses between 15 to 25 mcg/kg/min for pediatric patients <40m kg.
Today, I’m #20 on the call schedule after being #2 last night. It wasn’t bad… I left work around 7:30p and never got called back to the hospital. That’s a great #2 night! A couple of days ago, I awoke with a pinched nerve along the left side of my neck and it’s incredibly uncomfortable turning my head and just doing regular tasks (i.e. making the bed). Right now, I wreak of Bengay and I’m partially comforted with some Aleve. Hot compress, you are next! Sometimes, it’s really nice to enjoy a lazy morning with zero agenda other than to catch up on life and maybe even do some self reflection.
A buddy of mine sent me this article and asked me my thoughts….
I gave it a once over and thought, this is interested. A small sample size of various parents from various geographical regions all commenting on their children. Their is italicized because it seems like commenting on what the perfect number of children to have is so personal and completely unique to their experience.
It’s a heavy duty article with a lot of good perspective. I kind of agree with them all. I liked the one with 3 kids best… and the one with no kids the least. Since when did the purpose of procreation become about supporting the older generation? I had a tough one with that. I don’t think people have kids to look after them in old age.
What do u think?
This article came at a perfect time for me. Bear and I just got married; we’re older… and we’re looking to start a family. I just went on an Amazon spending spree for knowledge:
Even as an M.D., I am thirsty for knowledge in an area that I know pretty little about. Sure, I’ve rotated on OB/GYN as a med student — but that was back in 2005. Plus, doing two months of a rotation doesn’t equal a full understanding of mom’s body and baby’s development. It taught me how to safely deliver a baby, but I need to know and understand the building blocks leading up to that. Secondly, I’m an anesthesiologist who places labor epidurals for our pregnant ladies getting ready to welcome their little bundles of joy into the world. I typically meet the moms when they are having contractions and wanting pain control and follow-up with them at delivery. So you can see, there’s a 9 month knowledge gap that I need to fill in.
If you’re a future mom and are interested in an epidural, educate yourself on the pros and cons as well as what you expect to feel and when to ask for an epidural.
Remember, it is dependent on YOU as you are in control of your pain. A pain scale will vary from person to person (i.e. everyone has different pain tolerances). There’s no magical dilation number that tells you when to ask for an epidural. Keep in mind that you will need to hold extremely still when you do ask for an epidural. So please make it easy on your anesthesiologist (and yourself) and ask for an epidural when you are able to be as motionless as a statue — otherwise, it may be too risky to request an epidural if you are in too much pain to stay still.
“Now you can’t walk away from the price you pay” Bruce Springsteen, The Price You Pay…..I was called in at 2:30 a.m. recently for an aortic dissection. Seems like no one ever dissects in the middle of the day. When Dr. Newsome walked into the room he looked at me and said, ” it seems like we’ve done a few of these over the years.” Indeed we have…these cases are generally long and difficult. There is a feeling you get at the beginning of the case, usually around the time when you first see the patient, when you realize that you are more than likely going to be there anywhere from 8 to 12 hours or longer. It’s kind of a sinking feeling, especially if you had something planned that you were hoping to do, but the feeling recedes and you go about your business doing what must be done. It is a wonderful thing to be part of doing something that prolongs someone’s life. We are also financially compensated for what we do. But it comes with a price. It is a very surrealistic feeling to be driving home on a sunny Sunday evening at 6:00 p.m. after being at the hospital since 3 a.m. People are out enjoying life, surfing, riding bikes, going out to eat, whatever else they might enjoy, and all you want to do is make it home and fall into your bed. Basically, you have given up a day of your life. Which, at this stage, is not an infinite supply. It takes a toll on your body also. You feel like you’ve been run over by a truck. Everything hurts, and it’s usually a couple of days before you start to feel like yourself again. That being said, I can’t really complain as the scrub tech for the case was the amazing Ann McCullough who seems to have twice the endurance and stamina of someone half her age. Plus I got to spend the day with Drs Stahl, Wang and Newsome as well as Danny and Chad….priceless…oh yeah, at the end of the day when everyone was leaving Danny congratulated Chad on doing such a great job and said he would take call with him anytime. Seems like a small thing but the smile on Chads face told me it meant a lot to him. Things like that are why Danny is such a great person to work with…..