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SPA Newsletter.
Out and About the ASAAmerican Academy of Pediatrics Section on Anesthesiology Breakfast Panel Pushy Parents, Production Pressure and Crazed Kids; Pediatric Anesthesia in the New MilleniumModerator: Constance S. Houck, MDReviewed by: Anne E. Dickison, MD Three topics were selected to highlight issues encountered during changed pediatric anesthetic practices brought on by evolving economic forces, time/personnel considerations, product development, regulatory oversight, concerns for potential litigation, and political pressures in health care delivery today. The three topics were sequentially relevant to pre-operative, intra-operative, and post-operative areas of care. Pre-op: The Science and Politics of Parent-Present Induction Zeev. N. Kain, MD (Yale U. School of Medicine, New Haven, CT) presented his group's multifaceted study on Parental Presence during Induction of Anesthesia (PPIA), concentrating on the effectiveness of pre-op intervention and instruction. Studies have shown that compared to the effects of Parental Presence alone, children premedicated with oral midazolam are significantly less anxious and more compliant with induction of anesthesia. The Yale group found that PPIA offered no extra anxiolytic benefit than was achieved by oral midazolam without parental presence. On the other hand, parents who accompanied their sedated children into the operating room were significantly less anxious, more comfortable with the separation process, and they reported more satisfaction with the overall anesthetic, nursing, and surgical care given. Dr. Kain's studies sought to further identify which aspects of parental presence could most benefit the child, parents, and system. If certain behaviors improved both outcome and parental satisfaction, then instruction could be given to parents pre-operatively to modify behaviors and reinforce understanding of how to best contribute. Identified as positive methods of improving both pediatric and parental stress as measured by cortisol levels, vital signs, self-reporting, and third party observation were 1) Distracting methods (humor, toys, games), and 2) Commands to engage in actively rehearsed coping mechanisms. Assessed to be of no help during PPIA were 1) Empathy and "Everything will be OK" types of reassurance, 2) Apologizing, 3) Criticizing, 4) Bargaining, and 5) Giving the child control. On the basis of observations about which of the identified parental behaviors practiced pre-operatively could potentially improve a child's stress markers over midazolam alone, and concurrently reduce parental anxiety and/or improve parents' perceived satisfaction, an early intervention program was set up for clinical investigation. This program utilizes an instructional video, coaching, and phone calls starting a week before the planned anesthetic. Follow-up occurred in the PACU, prior to discharge, and two weeks after the procedure. Study groups were divided into those that ultimately received oral midazolam preoperatively (as well as PPIA interventional instruction), and those that ultimately received PPIA instruction alone. Politics influencing pediatric anesthesia practice, patient flow, and system permissiveness vary by institution, geographic part of the country, economic basis, surgeon acceptance, nursing beliefs, level of education and expectations of the population, personnel availability and distribution, and administrative vision. Successful introduction of any program of pre-operative parental instruction involves significant changes and buy-in from the various components. Local demographics and patient referral patterns tend to determine surgeon acceptance and their willingness to funnel parents into an instructive PPIA system as the child's surgery is scheduled. Among hospital administrators, 50% discourage pre-operative parental intervention, and only 10% of those surveyed supported the idea. Nurses, however, strongly support the idea of instructed PPIA, but their advocacy is not based on science, so it becomes easy for those in decision-making capacities to dismiss. To convince administrators, surgeons, nursing personnel, and other system components, data is necessary to prove that benefit is worth the added expense, effort, time, and disturbance to the way things are being done at present. Studies have established that in general parents want to be with their child during induction of anesthesia, but that over 90% of those who do go into the operating room experience significant anxiety. Thirty-two percent of parents change their minds about wanting to accompany their child to the OR if they see their child sedated in the holding area pre-operatively. Parental heart rate is highest upon entering the operating room, then diminishes during induction. Instructed parents show the same pattern but to a lesser degree. PP improves satisfaction with or without the use of sedatives. More questions were directed to Dr. Kain than he had time to answer. Sample questions: *Q: Were behavior changes [bedwetting, nightmares, school phobias, temper tantrums, etc.] or perceptions of satisfaction changed on a long-term basis? Dr. Kain: The midazolam group did benefit during the first seven days. Longer term effects of instructed PPIA and use of pre-operative sedation for a single operative procedure are not feasible to study because of the frequency of interaction by other unrelated factors like divorce, job loss, economic duress, birth or death of another sibling, need for further surgery, and a host of other influences on child and parent emotional well-being. *Q: How about Frequent Flyers? Dr. Kain: Results depended on the child's baseline personality and his previous exposure. Parents still wanted to go into the OR. *Q: Mother versus father? Dr. Kain: No difference in frequency of parental benefits, though mothers did report a higher anxiety during induction. To the child it did not matter whether the mother or father was the present parent in either the midazolam or non-midazolam groups. *Q: Have you ever sedated the parents? Dr. Kain: Problems with informed consent, who is responsible for supervision post-operatively, and driving home are all prohibitive issues. Acupuncture has been studied and is helpful, however. There may be a role for biofeedback, self-hypnosis, and other methods of non-pharmacologic intervention for achieving anxiety reduction for the parents of Frequent Flyers. Intraop: When and Why Should We Use Remifentanil? Peter J. Davis, MD (Children's Hospital of Pittsburgh, Pittsburgh, PA), pointed out that in patients less than 30 days of age, there are no labeled used for opioids, but neither do there exist any official sanctions for dopamine, dobutamine, or other drugs in common use in the neonatal population. Approval in the PDR is in large part a function of the drug industry's interest in doing studies. Consent for clinical trials, medicolegal worries, economics of reimbursement, nature of the population, and other factors inhibit processes for studying and approving potentially important agents to use for neonatal surgery. Dr. Davis reviewed a history of landmark studies evaluating opioids for use during procedures on neonates. Cited were Kupferberg (1963): baby rats were more sensitive to morphine sulfate, and had a higher death rate when given the same mg/kg dose. On necropsy they also had higher brain concentrations than their older controls. Zhang (1981): Mu and Mu-2 receptor pool increase with age, so the young get less analgesia from the same serum concentration. Robinson and Gregory (1970s-80s): The philosophy at this time for management of the sick neonate was to reduce lung water as much as possible, so babies were routinely and intentionally severely dehydrated. If Fentanyl 30 mcg/kg were administered during induction of anesthesia (as was advocated for congenital heart surgery), the blood pressure would inevitably bottom out. By preparing them with LR 10 cc/kg, the babies tolerated a fentanyl induction much better. Anand (1987): Classic demonstration that physiologic parameters of stress metabolism and survival statistics improved with the use of fentanyl during congenital heart surgery. Hertzka (1989): incidence of opioid-associated apnea was higher in neonates. Anne Lynn: Morphine sulfate concentration was the determining factor for prediction of respiratory depression. Discussing challenges to pharmacokinetic studies, Dr. Davis observed that individual variability of drug response in adults was 10-15%, and was even bigger in neonates. A drug resulting in less variability of response has a greater predictability of action. The most predictable responses occur when the drug does not accumulate, and when it does not require the liver for metabolism and excretion. With its highly lipid constitution, immature hepatic metabolism, and preoccupation by the liver for doing other chores like conjugating bilirubin, the neonate is particularly disadvantaged in terms of variability of response. He posited that studying variability of response of neonates to various opioids could potentially predict frequency of adverse side effects. Plotting Clearance (Y-axis) versus Duration of Infusion (X-axis), Dr. Davis plotted accumulation curves and hence determined variability for Fentanyl vs. Alfentanil vs. Sufentanil vs. Remifentanil. Fentanyl had the steepest slope and accumulated the most. Remifentanil had the flattest slope and hence accumulated the least. Remifentanil ended up with a 40% variability score, which was 1/3 of all others. The conclusion was that remifentanil, because of this "best" variability profile, offered significant advantages to the neonatal patient. In a study of well neonates undergoing surgery for pyloric stenosis, anesthetics with remifentanil were compared with variability scores obtained for a customary and standardized protocol for halothane. Awake extubation times were virtually identical. Variability measurements with remifentanil were half that of halothane, however. The conclusion was that remifentanil had a greater predictability of action than traditional halothane, and was hence more desirable. Furthermore, all patients received pre-op and post op pneumograms to assess their index of apnea. No babies with normal pre-op pneumograms had abnormal post-op apnea indices. In the halothane group, however, 3 out of 10 babies converted to abnormal apnea indices post-operatively. Results of this second method of clinical assessment correlated with determinations of variability from pharmacokinetic studies done on the same study group. Postop: Wild in the PACU Ira Todd Cohen, MD (Children's National Medical Center, Washington, DC) started out his session with a hilarious animated cartoon depicting emergence agitation and its effect on serenity in the PACU. Dr. Cohen deserves technical and artistic kudos for bringing down the house. Studies of emergence delirium are especially difficult to conduct and compare due to the variety of assessment tools and scales; definitions about what behavior constitutes disturbance during what specific periods of time; difficulties interpreting behavior in non-verbal populations with other influencing factors like pain, hunger, fear of strangers; and disagreeing opinions about the point at which a "normal" emergence transcends into the spectrum of "abnormal" post-operative dementia. DSM IV breaks down delirium into 1) Disturbance of consciousness, 2) Change in cognition, and 3) Fluctuations in the course of disturbance. Various scales used to study post-op delirium have included 3-point (1994); EAS: 5-point (2000); PAE: 5-point (2002); PAEDS: 5-point (2002), and PABA: DSM IV (2003) observation by trained psychologists. Risk factors for post-op delirium in the child less than 5 years of age, as reported by Voelpel-Lewis (in A&A 2003) include ENT and Ophthalmologic surgery, volatile anesthetic agents, intraoperative opioids, rapid emergence, and low adaptability. The incidence of emergence dysphoria in all comers was 12-18% and was highest on arrival from the OR to the PACU. Emergence delirium with desflurane was 40-60%, and was about the same for both painful and painless procedures. The incidence cited for sevoflurance was 30-50% whether or not the child arrived in PACU sleeping or was already agitated at the time of transport. Posited mechanisms of action include drug disposition, rapid emergence, dissociated states induced by various parts of the brain coming out of anesthesia at different rates, coexistent pain, underlying brain anatomy/chemistry/immaturity, and other factors influencing metabolism and excretion. The rapidity of emergence and coexistence of inadequately treated pain are not the full story, however, or the incidence of emergence dysphoria after a remifentanil-based anesthetic would not be less than what is seen with most other anesthetic agents, which is what has been observed in several other studies. Emergence phenomena leads to higher complication rates: increased bleeding from operative sites, pulling out of drainage tubes and IVs, pulling off of dressings, increased perception of pain and administration of pain medications, increased use of sedative medications with potential for drug interaction or increased respiratory depression, unhappy parents and nurses, disturbance and agitation of other patients in the PACU, and prolonged stays. To decrease the incidence of post-operative complications and prolongation of PACU stays, it is important to try to identify patients at risk for emergence delirium, or methods to abort it once it has occurred. Recommendations and observations coming forth from studies for preventing emergence phenomena in the pediatric patient include: 1) Avoid volatile agents (propofol and remifentanil seem to work very well for most procedures). 2) Fentanyl 1.25 mcg/kg for T&As, or intranasal fentanyl 1-2 mcg/kg for PE tubes 3) Ketorolac decreased post-op agitation in both sevoflurane and halothane groups 4) Propofol inductions did not decrease the incidence of post-op dysphoria 5) Midazolam pre-operatively or intraoperatively did not prevent and just seemed to delay emergence agitation occurring in the PACU 6) Oxycodone (Murray, 2002) did not decrease the incidence of agitation 7) Tramadol (Murrray, 2002) did not decrease the incidence of agitation Observations from the audience: *Dr. Charles Cote: In one of our studies in children with working caudals, the incidence of delirium was higher with sevoflurane than halothane on admission to PACU, but after five minutes, the incidence became the same. *Dr. David Polaner, quoting Dr. Elliot Krane: "Their ids wake up before their egos." Dr. Polaner endorsed the idea that different parts of the brain woke up at different rates. He referred the group to a poster on the role of GABA receptors on awakening. *Q: Once it happens, how should it be treated? Moderator: put the child back to sleep with propofol and let them wake up again. Dr. Cohen: administration of fentanyl (rather than meperidine or morphine) in the PACU. *Q: What is the best technique for a 5-year old for T&A? Dr. Cohen: Personally I prefer the combination of desflurane and fentanyl. Many institutions without access to desflurane are going back to halothane. Some anesthesiologists use a mask induction with sevoflurane but convert to isoflurane for the remainder of the anesthetic. Table of Contents
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