Premedication and Induction Aids

Premedication and Induction AidsAlyssa BrzenskiCaseYou are called by a parent of a child who you took care of a week and a half ago. The child, a 4 year old boy, came to IR for the first of many sclerotherapy of a Venous Malformation of the LLE. Per mom, the boy has been having night terrors and although he was previously potty trained has been wetting the bed almost every night. Case(cont)During the case the boy came back to the IR room with his mom, who was anxious at the time. He underwent a rocky mask induction. The remainder of the anesthetic was uneventful and he was discharged home following the procedure. Preoperative Anxiety

Pre-operative anxiety is associated with higher levels of stress hormones in the child throughout the perioperative period. It is also associated with increased pain levels throughout the perioperative period with the anxious child reporting higher pain levels through out the first 72 hours in kids undergoing T&A.4Post-op Delirium

Pre-op anxiety is also significantly associated with emergence delirium which is characterized by nonpurposeful restlessness and agitation, thrashing, crying, moaning and disorientation. From this graph we can see that the kids who had marked emergence delirium also had the highest level of anxiety in the preoperative holding area, on entrance to the OR and during induction.5Pre-operative Anxiety

However, pre-operative anxiety does not only lead to sequeale in the immediate post-op period but can also predispose to maladaptive behaviors which can extend up to 6 months after the childs perioperative event. Nearly 60% of unpremedicated kids can have some long-term sequale with separation anxiety being most common. However, they can also experience generalized anxiety, eating disturbances, apathy and withdrawal, sleep anxiety, aggression, or enuresis. 6Risk FactorsAgePrior stressful medical encountersTemperament- shy and inhibitedAnxious parents

Identifying risk factors for the anxious patient is important as it may alter your perioperative management. Children between the age of 1 and 5 years of age are at the highest risk, history of prior stressful medical encounters, patients with a shy inhibited temperament and patients with anxious parents are at increased risk of perioperative anxiety.7

Now that we have seen how detrimental pre-operative anxiety can be in the immediate and distant perioperative period and those kids who are at increased risk we can take a look at strategies to reduce the sequeale of the anxiety, specifically Parental Induction, Low sensory stimulation induction and then the majority of our time will be spent on pharmacologic options8Low Sensory Environment

Low sensory environment in which only one anesthesiologist speaks to the child and there is not background distractions, including the scrub tech moving a lot of equipment, and there is not loud distracting music in the background has been shown to reduce the stress of induction.9Parental Inductions

10Parental Induction vs Premed

However, when compared to premedication with oral midazolam parental induction does not reduce the childs stress level below that of an oral premed. Premedication has been how with a nearly 50% reduction in the post-operative sequeale, however, it is unclear how Parental Presence at Induction affects these longer term sequeale.11Distraction

In addition, distraction aids such as video games are also useful in reducing kids induction stress. Some are now extending this to using an i-phone or i-pad.12Pharmacologic InterventionsMidazolamKetaminePrecedexFinally, we will take a look at pharmacologic premeds that can be used. Ideally a pharmacologic premed would reduce anxiety, facilitate separation from a parent and induction, reduce post-op maladaptive behaviors. In addition, it would have a fast onset and not delay discharge from the PACU. Many kids who are not previously admitted to the hospital will not have an IV, forcing you to think about the route of administration as well.13Methods of AdministrationOralIntranasalSublingual/BucosalRectalIntramuscularMidazolamShort acting benzodiazepineImidazole ring allows for easy absorption across mucous membranes

Midazolam is the most commonly used premed given to adults with 75% of all adults receiving versed prior to entering the OR. The extremes of age, including the elderly(older than 75 years of age) and young children receiving it less. In fact as of a 10 years ago only 50% of kids were administered versed. As we all know Versed is a short-acting benzo with rapid onset and relatively quick elimination. In kids it has the advantage of having an imidazole ring allowing for easy absorption across mucous membranes, allowing for multiple routes of administration including oral, intranasal, rectal and intramuscular15Oral MidazolamLow bioavailability(27%) due to first pass metabolismDose= 0.2-0.5mg/kgOnset in 10 minutesPeak effect in 20 minutes

Oral versed used to be given from the IV formulation being mixed into Tylenol syrup but now there is a commercially prepared formulation. Different providers will administer different dosages ranging from 0.2-0.5mg/kg. With all being effective. However, the most commonly used dose of 0.5mg/kg has a faster onset of 10 minutes and peak effect in 20 minutes. In addition, the higher dose is associated with more anxiolysis. 16Oral MidazolamDecreases anesthetic requirementsDelays emergence and Stage I PACU recovery, but not discharge from the hospitalDecreases post-op maladaptive behavior

Oral Versed has been shown to reduce the anesthetic requirements by nearly 1/3. In addition there was a delay in emergence by an extra 6 minutes and prolongation of Stage I recovery by 14 minutes, but no change in discharge time from the hospital in patients receiving it for the short T&A procedure. As previously mentioned the incidence of post op maladaptive behavior is decreased by nearly 50% with oral versed. Finally, there are conflicting reports of increased emergence delirium in these patients. I personally will try very hard to not give oral versed to kids undergoing short procedures(ie T&A, Tubes) if possible, but will give it if necessary.17Other Routes for MidazolamIntravenous- 0.05-0.1 mg/kgNasal Midazolam- 0.2 mg/kgSignificant stinging during administrationPotential for neurotoxicity via the cribiform plate- use only preservative freeIntramuscular- 0.1-0.15mg/kgOnset within 10 minutesRectal- 0.5-1mg/kgAssociated with hiccups (22%)

Lets look at the other routes of administration of Midazolam. Intravenous versed can be given to the child with an IV at a dose of 0.05-0.1mg/kg with nearly immediate effects. Nasal midazolam can be administered via a nasal atomizer. It takes effect within 10 minutes. However, it is associated with significant stinging during administration. In addition, animal studies have suggested neurotoxicity via access by the cribiform plate so it should not be administered unless preservative free. IM dose is also associated with significant stinging. Finally, rectal doses can be given but hiccups are observed in 22% of patients. Finally, in patients undergoing lengthy procedures, such as heart surgery or scoliosis surgery oral diazepam can be a better choice but it takes 18KetaminePhencyclidineProduces sedation and analgesia while preserving respiratory drive and upper airway toneIncreased sympathetic stimulation, direct cardiac depressantAssociated with increased oral secretions, nystagmus, increased post-op nausea and vomitingLess post-op delirium in kidsIntramuscular KetamineA good option for the child who refuses to take oral medication or who is combativeDose = 2-5 mg/kgCan add atropine/glyco to reduce secretionsCan add midazolamSignificantly prolongs recovery during short procedures20KetamineIntravenous- 1mg/kg Oral- 5-6mg/kg sedates within 12 minutesNasal- 6mg/kgPotentially neurotoxicRectal- 5mg/kg sedates within 30 minutesPrecedex-2 agonist- sedation with maintence of spontaneous respiration

Intranasal Precedex

1mg/kg of intranasal precedex was shown to have better sedation than oral versed, with significantly signifant better sedation during sedation at separation than versed or 0.5mg/ml intranasal precedex. There were statistically significant improved sedation at induction, however there was also a greater change of sedation. It takes about 45 minutes to take effect and may prolong recovery in short procedures.23ConclusionPerioperative anxiety can be associated with increased pain scores, post-operative delirium and prolonged regression and maladaptive behaviorsThere should not be a 1 size fits all approachHowever, a tailored plan should be made for high risk patients while being cognizant of pre-operative and post-operative/PACU effects.SourcesKain Z, et al. Predicting Which Child-Parent Pair Will Benefit from Parental Presence During Induction of Anesthesia: A Decision-Making Approach. Anesthesia and Analgesia. 2006; 102:81-4.Green S, Cote C. Ketamine and Neurotoxicity: Clinical Perspectives and Implications for Emergency Medicine. Annals of Emergency Medicine. 2008; 1-9.Yuen VM, Hui TW, Irwin MG, Yuen MK. A Comparison of Intranasal Dexmedetomidine and Oral Midazolam for Premedication in Pediatric Anesthesia: A Double-Blinded Randomized Controlled Trial. Anesthesia and Analgesia. 2008; 106: 1716-21.Kain Z, et al. Preoperative Anxiety, Postoperative Pain, and Behavioral Recovery in Young Children Undergoing Surgery. Pediatrics. 2006; 118: 651-8.Kain Z, et al. Preoperative Anxiety and Emergence Delirium and Postoperative Maladaptive Behaviors. Anesthesia and Analgesia. 2004; 99: 1648-54.Kain Z, et al. Preoperative Anxiety in Children: Predictors and Outcomes. Arch Pediatric and Adolescent Medicine. 1996; 150: 1238-45.Kain Z, et al. Sensory Stimuli and Anxiety in Children Undergoing Surgery: A Randomized, Controlled Trial. Anesthesia and Analgesia. 2001; 92: 897-903.Patel A, et al. Distraction with a Hand-Held Video Game Reduces Pediatric Preoperative Anxiety. Pediatric Anesthesia. 2006; 16: 1019-27.