Opioid Free Anesthesia Michael H Wilhelm, CRNA, APRN Opioid Free Anesthesia Michael H Wilhelm, CRNA, APRN 1
Why is pain important? Primary contributor to post-operative distress 56% of patients state that this is the major concern about surgery 75% of patients state that inadequate pain management during their care at a facility This can lead to certain factors: Prolonged hospital stays Unnecessary readmissions Increased morbidity Increased healthcare costs Can lead to chronic pain syndromes Indications for Opioid Free Anesthesia Obese Patients Obstructive Sleep Apnea Acute and Chronic Opioid Addiction Previous Hyperalgesia Problems Patients with severe PONV 2
Contraindications to Opioid Free Anesthesia Absolute Allergy to any of the adjuvant drugs Relative Consider side effects of adjuvant drug side effects Do we need a new method of anesthesia? Aims of a surgical anesthetic Amnesia Analgesia Control of autonomic effects Rapid Emergence Opioids were the ideal product to meet this aim, but are they still as necessary with less cardiovascular suppressant anesthetic drugs. 3
Why should we practice opioid sparing/free Opioids have traditionally been the first line therapy for surgical pain control Opioid drugs produce pharmacologic properties by binding to opiate receptors, located in the CNS, supraspinal and spinal and peripheral sites Side effects of opioid unwanted effects are seen about 30% Can exacerbate obstructive sleep apnea and increase its severity Opioid tolerance can happen even after a single dose Decrease the chances of opioid related side effects such as: Delayed emergence GI side effects such as ileus, constipation, nausea and vomiting Respiratory Depression Pruritus Urinary Retention Tolerance by desensitization Reduced cardiac output Short duration of central muscle stiffness Acute Tolerance and Hyperalgesia Potent opioids may be rapidly eliminated and lead to acute tolerance which may lead to increased postoperative pain This has been labeled the opioid paradox The more opioids given intraoperatively the more is needed postoperatively and the higher pain scores will be Prolonged exposure to opioids shifts the dose-response curve in such a way that larger doses of opioids are needed over time to render the same level of analgesia (Opioid Tolerance) 4
Drugs Available to Reduce Opioid Requirements We need to block the sympathetic system Opioids at one time were the only option Today we have many drugs that that can work in the same manners Direct Central or peripheral sympathetic block Clonidine Dexmedetomidine Beta-Blockers Indirect Blockers Calcium Channel Blockers Lidocaine Magnesium Sulfate Inhalational Agents Multimodal pain management is the best way to reduce opioid consumption. Multimodal analgesia includes local anesthetic as well as systemic drugs and aim to reduce the dose of any single agent thereby reducing the potential for adverse effects A stable anesthetic can be delivered with the multimodal approach of sympatholytic drugs and non-opioid analgesics This can result in the reduction or avoidance of opioids in the postoperative area 5
What are the options to lead to opioid free? Different drug classes that can be used to help with pain relief Regional Anesthesia Alpha-2 Agonists Pharmacologically they are suitable for a multimodal approach Can cause sedation, hypnois, anxioloysis, sympatholysis and analgesia Clonidine was used in this fashion in the 1980 s Today dexemedtomidine is a better replacement Intial Bolus leads to activiation of alpha-2 receptors on vascular smooth muscle Intial vasoconstriction and a transient increased blood pressure with a reflex bradycardia Following the bolus a more gradual central effect is seen with sedatin and decrease in sympathetic outflow The antinociceptive effect is belived to be from the a2-adreno receptors in the central nervous sytem and spinal cord 6
Lidocaine Sodium Channel Blocker Can provide excellent pain relief when given intravenously Analgesic, antihyperalgesic and anti-inflammatory effects Advantages Decreased intraoperative anesthetic requirements Reduces opioid requirements with a reduction of opioid side effects Faster return of bowel function Good for abdominal cases Decreased duration of hospital stay Shown to decrease hospital stay by one day In the outpatient setting it demonstrated less opioid requirements, faster discharge and decreased PONV Lidocaine Meta-Analysis by Dunn & Duriex (2017) stated that lidocaine infusions can be delivered in various fashions but that the most common was as follows: Bolus on Induction 1.5 mg/kg followed by an infusion of 1-3mg/kg/hr The infusion could be discontinued on emergence but could also be continued in PACU and the floor for up to 2 days. 7
Esmolol Ultra-Short Acting cardioselective beta1 adrenergic receptor antagonist Rapidly hydrolyzed by red blood cell esterases Duration of action of about 9 minutes Can be targeted to attenuate unwanted autonomic responses Studies have demonstrated that it also has analgecis properties In the past has been recommended in replacement of opioids Advantages Has been shown to result in earlier discharge Because of reduced narcotics, reduced incidence of PONV Increased patient satisfaction Esmolol In a study by Margarita et al. (2001) they utilized an esmolol infusion instead of a remifentanil infusion during outpatient GYN Cases Less Nausea 4% with esmolol vs 35% in remi group Faster discharge times 112 min with esmolol vs 151 min with remi Esmolol dose on induction was 1mg/kg followed by infusion prior to skin incision of 5mcg/kg/min and discontinued on completion of case. 8
Magnesium Activates NMDA receptors causing calcium entry into the cell and triggering central sensitization NMDA receptors control ion channels and depolarization of 2nd order neurons Works as a non-competitive antagonist of NMDA glutamate receptors Leads to a voltage dependant block of NMDA receptors by blocking the entry of calcium and sodium into the cells Prevents depolarization and transmission of pain signals Ketamine receptor prevents efflux of potassium Magnesium Ryu, Kang, Park and Do (2008) demonstrated in a double blind, prospective study that Magnesium reduced the amount of Rocuronium used in a case and also improved the quality of postoperative analgesia. Rocuronium use on Group Magnesium was 35 mcg/kg/min vs Group Saline 44 mcg/kg/min Propofol and Remifentanil delivery were similar in both groups Postoperative pain scores, cumulative analgesic consumption and shivering incidents were significantly reduced. On induction Magnesium was delivered with a bolus of 50 mg/kg followed by an infusion of 15 mg/kg/hr. 9
Ketamine Unique intravenous anesthetic with analgesic properties Small doses (0.1-0.2mg/kg) have shown to provide opioid sparing effect Greater patient and physician acceptance because of the less frequency of side effects Studies show mixed results with regard to benefit, but no demonstration of harm Pretreatment with ketamine has shown attenuation of opioid induced hyperalgesia. Seems to hold particular benefits for the opioid tolerant patient and significantly improves the postoperative management during the first few days following surgery. Ketamine At doses of 0.5mg/kg as a bolus or infusions exceeding 0.5mg/kg/hr have been found to be associated with increased neuropsychiatric effects. 4 At doses less that 0.5mg/kg it reduces postoperative analgesic needs and this is especially seen in the opioid tolerant patient. 4 Some authors recommend that opioid tolerant patients should receive a 5-10mg/hr ketamine infusion postoperatively and this may be continued for weeks. 5 10
Dexamethasone Potent corticosteroid lacking of mineralocorticoid effects Used as an antiemetic when given at a dose of 50mcg/kg on induction At doses of 100mcg/kg it has been demonstrated to have analgesic properties 6 Reduced pain scores and decreased narcotic need by patient shown within 24 hours of procedure It is believed that this if from the anti-inflammatory properties leading to less edema formation and less pain at operated site 6,7 Suggested to be given prior to incision as this may limit inflammation, preoperative administration may be more beneficial as onset of action is 1-2 hours, but we may see the painful perineal sensation 7 Optimal dose suggested in literature is 0.1-0.2mg/kg 7 Gabapentinoids Limits facilitation of pain transmission by inhibiting the voltage gated calcium channels on sensory neurons Has demonstrated benefits in the management of neuropathic pain Multiple studies have shown a role for acute postoperative pain Reduces opioid consumption by about 33% when given as a premedication 5 Side effect of dizziness and lack of coordination 11
Case Example - Pre-Op Procedure: Laparoscopic Total Hysterectomy with removal of Fallopian Tubes and Ovaries. Patient Information: 5 11 111kg BMI-36 Age-52 Allergies: Codeine and PCN PMH: HTN, Denies OSA, Denies Smoking, GERD PSH: Lap Chole, D&C, Toe Surgery, C-Section X 2 Airway: MPII, teeth intact no cervical limitations Induction Pt was brought to the OR uneventful and attached to all monitors and preoxygenated with O2. Premedicated with Versed 2mg Induction Fentanyl 50mcg, Propofol 100mg, Magnesium 2gms, Lidocaine 1.5mg/kg, Rocuronium 50mg Intubation was uneventful and ETT placed Pt was given a TAP Block Bilateral with 30ml 0.25% Bupivicaine on each side 12
Intra-Op After induction the following was done: Ofirmev 1000mg IV Lidicaine 2mg/kg/hr for duration of case Decadron 10mg Zofran 4mg Toradol 30mg Lopressor 2mg Anesthesia was maintained with Sevoflurane at 2% and Rocuronium was redosed for a total of 30mg Emergence Pt reversed with Sugammadex 200mg Lidocaine infusion was discontinued Emergence and extubation was uneventful Patient delivered to PACU with normal order set and after visiting the patient later in the day only received another 12.5mcg Fentanyl and was sent to the floor and discharged the following day. During stay at hospital patients pain resulting in only one incident of 6/10 pain all others were 5/10 or below. Pt pain was managed with Ibuprofen and Tylenol during stay till discharge. 13
References 1. Dunn LK, Durieux ME. Perioperative Use of Intravenous Lidocaine. Anesthesiology. 2017;126(4):729-737. doi:10.1097/aln.0000000000001527. 2. Coloma, M, Chiu, J, White, P & Armbruster, P. The Use of Esmolol As an Alternative to Remifentanil During Desflurane Anesthesia for Fast-Track Outpatient Gynecologic Laparoscopic Surgery. Survey of Anesthesiology. 2001;45(6):321-322. doi:10.1097/00132586-200112000-00003. 3. Ryu J-H, Kang M-H, Park K-S, Do S-H. Effects of magnesium sulphate on intraoperative anaesthetic requirements and postoperative analgesia in gynaecology patients receiving total intravenous anaesthesia. British Journal of Anaesthesia. 2008;100(3):397-403 4. Hodgson, E. Sticky concepts in anaesthetic practice. FMM. 2015. 5. Viscomi, CM. Postoperative analgesia: elements of successful recovery. Anesthesiology. 2013; 55(25). 6. De Oliveira, GS, Almeida, MD, Benzon, HT, McCarthy, RJ. Perioperative single dose systemic dexamethasone for postoperative pain: a meta-analysis of randomized controlled trials. Anesthesiology. 2011; 115(3):575-588. 7. Waldron NH, Jones CA, GAN TJ, Allen TK, Habib AS. Impact of perioperative dexamethasone on postoperative analgesia and side effects: systematic review and meta-analysis. British Journal of Anaesthesia. 2013; 110(2):191-200. 14