ARTICLE DOI: 10.31480/2330-4871/109
Letter to Editor OPEN ACCESS
Response: Ketamine Hallucination & Dose Limits Rebutted
Christian Bohringer, MD, Carlos Astorga, MD and Hong Liu*, MD, FASE
Department of Anesthesiology and Pain Medicine, University of California Davis Health, Sacramento, California, USA
Hong Liu, MD, FASE, Professor, Department of Anesthesiology and Pain Medicine, University of California Davis Health, 4150 V Street, Suite 1200, Sacramento, CA 95817, USA, Tel: 916-734-5031, Fax: 916-734-7980, E-mail: firstname.lastname@example.org
Editor: Renyu Liu, MD, PhD, Associate Professor, Department of Anesthesiology and Critical Care, Perelman School of Medicine at the University of Pennsylvania, Center of Penn Global Health Scholar, Director of Stroke 120 Special Task Force, Chinese Stroke Association, 336 John Morgan building, 3620 Hamilton Walk, Philadelphia, PA 19104, USA, Phone: 2157461485, Fax: 2153495078, Email: RenYu.Liu@pennmedicine.upenn.edu
Received: December 13, 2019 | Accepted: December 15, 2019| Published: December 20, 2019
Citation: Bohringer C, Astorga C, Liu H. Response: Ketamine Hallucination & Dose Limits Rebutted. Transl Perioper & Pain Med 2020; 7(1):174-175.
We sincerely thank Dr. Friedberg for having pioneered the concept of Opioid Free Anesthesia (OFA) and for his valuable reflection  about our recent paper "The Benefits of Opioid-Free Anesthesia and the Precautions Necessary when Employing it" . As part of our practice in a large urban trauma center, we have to anesthetize most of our patients and the operations usually involve major physiological changes. Both circumstances lead to a significant activation of the sympathetic nervous system and make us conservative with the size of our bolus doses of ketamine.
We concede that in patients undergoing monitored anesthesia care for elective plastic surgery which is the area of Dr. Friedberg's expertise, larger doses of ketamine can be administered without producing excessive tachycardia.
However, we would like to reaffirm that in our patient population it is more cautious to administer multiple small doses of ketamine rather than a single big one if the patient has ischemic heart disease and is undergoing major surgery induced sympathetic stimulation. A low dose ketamine is effective in providing intraoperative analgesia [3,4]. Alternatively, dexmedetomidine can be given before ketamine to prevent tachycardia after a larger dose of ketamine.
We do occasionally observe hallucinations after ketamine in the recovery room and this may be due to many of our patients recreationally abusing methamphetamines. A recent study found that a combination of ketamine and amphetamine was associated with greater psychotic effects than methamphetamine alone . Many of our patients also undergo prolonged operations with major fluid shift, electrolyte imbalance and blood transfusion. This may be another reason why we, unlike Dr. Friedberg, occasionally see hallucinations after ketamine.
Ketamine together with magnesium is an invaluable tool for the treatment of pain in patients with opioid induced hyperalgesia and in Dr. Friedberg's observation has successfully eliminated opioid induced nausea and vomiting. In Dr. Friedberg's plastic surgery experience, both tachycardia and hallucinations after ketamine were also prevented by prior administration of propofol [6,7]. We believe that this difference in observation has its origin in the difference in patient populations and the nature of the surgery being performed in our respective institutions. We would like to once again thank Dr. Friedberg for his valuable feedback and for having pioneered the growing field of opioid free anesthesia.
This work was supported by the University of California Davis Health Department of Anesthesiology and Pain Medicine, and NIH grant UL1 TR001860 of the University of California Davis Health.
- Friedberg BL. Ketamine Hallucination & Dose Limits Rebutted. Transl Perioper & Pain Med 2020; 7(1):170.
- Bohringer C, Astorga C, Liu H. The Benefits of Opioid Free Anesthesia and the Precautions Necessary When Employing it. Transl Perioper & Pain Med 2019;7(1):152-57.
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- Friedberg Bl. Propofol-ketamine technique, dissociative anesthesia for office surgery: a five year review of 1,264 cases. Aesth Plast Surg 1999;23:70-74.
- Friedberg BL. Hypnotic doses of propofol block ketamine induced hallucinations. Plast Reconstruct Surg 1993;91:196