The dose-effect relationship for morphine and vomiting after day-stay tonsillectomy in children

Pharmacokinetic modeling and simulation to understand diamorphine dose-response in neonates, children, and adolescents

Pharmacokinetic-pharmacodynamic modeling and simulation can facilitate understanding and prediction of exposure-response relationships in children with acute or chronic pain. The pharmacokinetics of diamorphine (diacetylmorphine, heroin), a strong opioid, remain poorly quantified in children and dose is often guided by clinical acumen. This tutorial demonstrates how a model to describe intranasal and intravenous diamorphine pharmacokinetics can be fashioned from a model for diamorphine disposition in adults and a model describing morphine disposition in children. Allometric scaling and maturation models were applied to clearances and volumes to account for differences in size and age between children and adults. The utility of modeling and simulation to gain insight into the analgesic exposure-response relationship is demonstrated. The model explains reported observations, can be used for interrogation, interpolated to determine equianalgesia and inform future clinical studies. Simulation was used to illustrate how diamorphine is rapidly metabolized to morphine via its active metabolite 6-monoacetylmorphine, which mediates an early dopaminergic response accountable for early euphoria. Morphine formation is then responsible for the slower, prolonged analgesic response. Time-concentration profiles of diamorphine and its metabolites reflected disposition changes with age and were used to describe intravenous and intranasal dosing regimens. These indicated that morphine exposure in children after intranasal diamorphine 0.1 mg.kg-1 was similar to that after intranasal diamorphine 5 mg in adults. A target concentration of morphine 30 μg.L-1 can be achieved by a diamorphine intravenous infusion in neonates 14 μg.kg-1 .h-1 , in a 5-year-old child 42 μg.kg-1 .h-1 and in an 15 year-old-adolescent 33 μg.kg-1 .h-1 .

comparison of palonosetron and aprepitant for prevention of post operative nausea and vomiting in females undergoing laparoscopic hysterectomy under general anesthesia

Background: Postoperative nausea and vomiting (PONV) is the second most common complaint following pain after surgery. In this era of daycare and outpatient-based surgery, PONV is the cause of delayed recovery and discharge from hospital settings. This study was designed to compare Palonosetron and Aprepitant for the prevention of PONV in patients undergoing laparoscopic hysterectomy under general anesthesia. Methods: 70 patients were included in this randomized double-blind study. Each group was allocated to receive either 0.075 mg of intravenous Palonosetron or 40mg of oral Aprepitant for PONV prophylaxis. A standard regimen of general anesthesia was administered to both groups for surgery. The primary outcome was the PONV impact severity scale (PISS) score at 48 hours following surgery in both groups. Secondary outcomes were the incidence of clinically significant PONV in both groups and the requirement of rescue antiemetics.  Results: Mean PISS score at 48 hours was significantly lower (0.91±0.13 vs 3.43±0.2) in the Palonosetron group than in the Aprepitant Group. Incidence of PONV (16/35 vs 33/35) was significantly lower with Palonosetron. Incidence of clinically significant PONV and requirement of rescue antiemetics was significantly lower (2/35 vs 13/35) in the Palonosetron group. 

Is Prevention of Postoperative Vomiting Surgery Dependent? A Retrospective Cohort Study of Total Knee Arthroplasty

The study of postoperative nausea and vomiting (PONV) has been ongoing since the early days of general anesthesia. The search for risk factors of PONV and the development of new agents to treat PONV are the two main strategies to combat the adverse side effects of general anesthesia. Female sex, non-smoking status, a history of PONV/motion sickness, and postoperative opioid use are the four independent risk factors for PONV derived after a series of prospective studies, evidence-based systematic reviews, and meta-analyses. The two frequently asked questions that arise ask whether risk factors apply to different clinical settings and whether prevention measures of PONV can be surgery dependent. We conducted a comprehensive review of 665 patients who underwent primary total knee arthroplasty (TKA) between January and December 2019. As nausea is subjective and its measurement is not standardized, postoperative vomiting (POV) was used as a study endpoint. The exclusion criteria were desflurane anesthesia, spinal anesthesia, anesthesia without bispectral index monitoring, and day surgery. Three well-recognized risk factors, consisting of body weight, sevoflurane consumption, and postoperative opioid consumption, were not considered as independent risk factors of POV, while female sex, preoperative adductor canal block (ACB), and dexamethasone were identified as being so in this study. The risk of POV in the female sex was 2.49 times that in the male sex; however, when dexamethasone was used, this risk was reduced by >40% compared with no antiemetic use, and by >50% when patients received preoperative ACB compared with those without the block. The clinical characteristics of our TKA patients—female dominance, old age, and their fairly constant body weights that were distinct from those of other surgical patients—suggested that age may play a crucial role in determining the relative contributions of the different risk factors of POV. We concluded that risk factors of POV are dependent on clinical settings. Based on these results, it is reasonable to speculate that a surgery-dependent plan for the prevention of POV is feasible for patients in similar clinical settings.

Risk Factors of Postoperative Vomiting in the Eye of "Real-World Evidence"-Modifiable and Clinical Setting-Dependent Risk Factors in Surgical Trauma Patients

Numerous studies on postoperative nausea and vomiting (PONV) have been carried out since the early days of contemporary surgery. The incidence of PONV has been greatly reduced in recent years and new drugs for PONV keep evolving in the market; however, a substantial number of patients are still under the threat of PONV. Female gender, non-smokers, a history of PONV/motion sickness, and postoperative opioid use are four well-recognized risk factors of PONV. Many potential risk factors reported in previous studies were not consistently presented as predictors for PONV. Two questions then arise; are risk factors clinical setting dependent and are risk factors modifiable? We attempted to answer the questions through a comprehensive review of perioperative records of surgical patients from the Trauma Department of our hospital. As nausea is subjective and no standard is applicable for its measurement, postoperative vomiting (POV) was used as an endpoint in this study. To the best of our knowledge, this is the first study to address the POV issue in surgical trauma patients. A total of 855 patients were enrolled in this study after excluding age below 20 years old, total intravenous anesthesia, desflurane anesthesia, or records with missing data. Our results showed that female gender (OR 4.89) is the strongest predicting factor, followed by a less potent predicting factor—more intraoperative opioid consumption (OR 1.07)—which favor more POV. More intraoperative crystalloid supply (OR 0.71) and a higher body weight (OR 0.9) favor less POV. Other potential risk factors did not reach statistical significance in this study as independent risk factors. Our results also showed that when the intraoperative crystalloid infusion rate is greater than 4 mL/kg/h (OR 0.20), it favors a lower rate of POV; when intraoperative opioid consumption is greater than 12 mg morphine equivalents, MME (OR 1.87), it favors a higher rate of POV. We concluded that dominance of any independent risk factor over other risk factors depends on how individual factors interact with the clinical setting. Some risk factors could be modified, and a cut-off value could be derived to facilitate a better plan for POV prevention.

Nasal Sprays Containing Mometasone Furoate for Relief of Post-Adenotonsillectomy Pain in Children: A Prospective Controlled Study

Objectives

Adenotonsillectomy is one of most common surgeries performed in childhood. Post-operative pain associated particularly with tonsillectomy is still a problem for many physicians. Despite advances in surgical techniques, analgesics, or anti-inflammatory drugs, no unique strategy for post-tonsillectomy pain management has been suggested. The aim of this study is to investigate the analgesic effect of steroid containing nasal spray applied to tonsillar region after tonsillectomy.

Methods

Eighty-two patients were assigned into two groups as study and control. In study group, nasal spray containing steroid was applied to each tonsillar region after surgery for 5 days. Post-operative pain of all patients was assessed using a visual analog scale and results were compared.

Results

Pain decreased gradually over time in both the study and control groups. Although the pain scores from 4 h post-surgery to post-operative day 5 were not found to significantly decrease in children that used nasal spray containing steroid, these patients developed less pain on post-operative day 5,with statistical significance (p<0.05).

Conclusion

Post-tonsillectomy pain was reported to increase around post-operative day 5, which coincides with the time of intense wound inflammation. Therefore, significant pain reduction on post-operative day 5 observed in children that used nasal spray with steroid may have clinical importance for overcoming this problem.

Addition of dexmedetomidine to ropivacaine for local infiltration anaesthesia improves analgesic efficacy after tonsillectomy and adenoidectomy: A randomized controlled trial

OBJECTIVES

The aim of this study was to determine whether the addition of dexmedetomidine to ropivacaine for local infiltration anaesthesia was more effective than ropivacaine alone in attenuating pain after tonsillectomy and adenoidectomy.

METHODS

This was a double-blind randomized clinical trial. One hundred and twenty children scheduled for tonsillectomy and adenoidectomy using a combination of general anaesthesia and local infiltration anaesthesia were randomized into the dexmedetomidine plus ropivacaine group (DR) and ropivacaine group (R). The children were locally infiltrated with 1 μg kg^-1 dexmedetomidine and 0.25% ropivacaine in the DR group or 0.25% ropivacaine alone in the R group. In both groups, local infiltration anaesthesia was performed using 5 ml of solution. The pain scores were recorded at the 1st, 4th, 8th, 12th, 16th, 20th, and 24th hours after surgery using the Face Legs Activity Cry Consolability (FLACC) scale. When the pain score exceeded 4, paracetamol syrup (15 mg kg^-1) was administered as a rescue analgesic. Time to the first administration of analgesic was recorded.

RESULTS

8th, 16th, 20th, and 24th hours after surgery, the children in the DR group had lower pain scores than those in the R group (P<0.05). The time to the first administration of analgesic was significantly longer in the DR group (mean: 10.4 h, range: 9.4-11.4 h) than in the R group (mean: 8.1 h, range: 7.3-8.8 h) (P < 0.001).

CONCLUSION

The addition of dexmedetomidine to ropivacaine for local infiltration anaesthesia effectively improved the efficacy of analgesia and extended the duration of analgesia after tonsillectomy and adenoidectomy.

Hypopharyngeal packing during adenotonsillectomy by cold dissection in children: a randomized controlled trial

PURPOSE

Nausea and vomiting occur in up to 70% of children after adenotonsillectomy, ingested blood during procedure being one of the reasons for emesis. Hypopharyngeal packing (HP) is a common practice among otolaryngologists to prevent blood from being swallowed, but studies in nasal surgeries in adults failed to show efficacy of this technique in reducing postoperative nausea and vomiting (PONV). There are no studies evaluating the effect of HP in adenotonsillectomy in children. The aim of this study is to evaluate the efficacy HP during adenotonsillectomy in children in the prevention of PONV.

METHODS

This is a randomized, double-blinded, controlled trial. Children aged 4-16 years, scheduled for adenotonsillectomy due to sleep-disordered breathing were enrolled in Hospital da Criança Santo Antônio (Brazil). 192 participants were screened, while 129 were enrolled and completed follow-up for primary outcome. Patients were randomized in a consecutive manner to receive HP or not during adenotonsillectomy. PONV occurrence was assessed in the first 24 h after surgery in HP and control group and relative risk with 95% confidence interval was calculated.

RESULTS

There were 129 patients randomized, 64 in the HP and 65 in the control group. Female were 40.3% and mean ± SD age was 7.3 ± 2.9. Baseline characteristics and surgery variables were distributed similarly between the groups. Incidence of PONV was 20.3% in the HP and 23.1% in the control group. The relative risk for PONV was 0.88 (95% CI 0.46-1.70).

CONCLUSION

Our results suggest that there is no benefit of HP during adenotonsillectomy in children for the prevention of PONV.

TRIAL REGISTRATION

Brazilian Register of Randomized Trials (REBEC) identifier: RBR-3zjn27; Universal Trial Number U1111-1197-7461.

The Society for Pediatric Anesthesia recommendations for the use of opioids in children during the perioperative period

Opioids have long held a prominent role in the management of perioperative pain in adults and children. Published reports concerning the appropriate, and inappropriate, use of these medications in pediatric patients have appeared in various publications over the last 50 years. For this document, the Society for Pediatric Anesthesia appointed a taskforce to evaluate the available literature and formulate recommendations with respect to the most salient aspects of perioperative opioid administration in children. The recommendations are graded based on the strength of the available evidence, with consensus of the experts applied for those issues where evidence is not available. The goal of the recommendations was to address the most important issues concerning opioid administration to children after surgery, including appropriate assessment of pain, monitoring of patients on opioid therapy, opioid dosing considerations, side effects of opioid treatment, strategies for opioid delivery, and assessment of analgesic efficacy. Regular updates are planned with a re-release of guidelines every 2 years.

Parent/Nurse-Controlled Analgesia Compared with Intravenous PRN Opioids for Postsurgical Pain Management in Children with Developmental Delay: A Randomized Controlled Trial

Objectives

The aim of this study was to conduct a randomized, controlled comparison of outcomes associated with parent/nurse-controlled analgesia (PNCA), with and without a basal (background) opioid infusion, with intravenous (IV) opioids intermittently administered by a nurse on an "as needed" basis (IV PRN) for postoperative pain management in children with developmental delay (DD).

Methods

Participants included children with DD expected to require IV opioids for at least 24 postoperative hours. Patients were randomized to one of three groups: PNCA with a basal infusion, PNCA without a basal infusion, or IV PRN opioids. Demographics, pain scores, opioid consumption, and frequency of side effects were collected beginning 12 hours after emerging from anesthesia to decrease the impact of anesthetic agents on outcomes.

Results

The 81 participants (median = 12.0, 9.0-15.0 years) were primarily Caucasian (74%) males (58%), with severe DD (69%) having spinal surgery (41%). The proportion of patients in each group with pain scores ≤3 vs ≥ 4 revealed no between-group differences in any epoch (P = 0.09-0.27). Patients in the PNCA with a basal group consumed significantly more opioid (median = 0.03 mg/kg/h morphine equivalents, 0.02-0.03 mg/kg/h) than the PNCA without a basal infusion. No difference was found between the PNCA without a basal (median = 0.01 mg/kg/h morphine equivalents, 0.00-0.02 mg/kg/h) and the PRN groups (median = 0.01 mg/kg/h morphine equivalents, 0.01-0.02 mg/kg/h). There were no statistically significant differences in side effects, with the exception that more children in the PNCA group required supplemental oxygen (P = 0.05).

Conclusions

Results suggest there may be no advantage to PNCA over PRN opioids in this patient population after the first 12 postoperative hours with regard to pain scores, opioid consumption, or side effects.

A comparison of intraoperative haemostatic techniques during tonsillectomy: Suture vs electrocautery-A study to assess postoperative pain scores and duration to resumption of normal diet

OBJECTIVES

To assess postoperative pain and pattern of recovery to normal diet in children who underwent tonsillectomy.

METHODS

Cold steel tonsillectomy (or adenotonsillectomy) was performed in 61 children. Haemostasis was attained with sutures in Group 1 (n = 30, 8 tonsillectomy and 22 adenotonsillectomy), and electrocautery in Group 2 (n = 31, 6 tonsillectomy and 25 adenotonsillectomy). Information obtained included postoperative pain scores and the number of postoperative days taken to resume normal diet. The pain score was evaluated with the Wong-Baker FACES^® Pain Rating Scale (WBFS).

RESULTS

Pain values in Group 1 (haemostasis with sutures) were significantly lower than those in Group 2 (haemostasis with cauterisation) from the 6th hour to the 7th postoperative day (P < .05). For both liquid and solid food, Group 1 returned to normal diet earlier, compared to Group 2 (P < .05). When comparing patients undergoing tonsillectomy vs adenotonsillectomy, resumption of normal diet was achieved later in the adenotonsillectomy patients (P < .05). In terms of postoperative bleeding, there were 2 significant events in Group 2 (electrocautery group), occurring on the 1st (severe) and 10th day (slight) in 2 children (6.5%). There were no postoperative bleeding events in Group 1.

CONCLUSION

Our results showed that suture haemostatis causes less pain and faster resumption of normal diet compared to electrocautery. In view of this, we recommend the use of sutures for achieving intraoperative haemostasis in paediatric patients.

Comparison of topical ropivacaine with and without ketamine on post-surgical pain in children undergoing tonsillectomy: a randomized controlled double-blind study

PURPOSE

Tonsillectomy in pediatric patients may cause severe postoperative pain. Topical local anesthetics are an easy and safe way to control post-tonsillectomy pain, but there is no benefit during the early postoperative stage. Topical ketamine shows a good effect on early stage postoperative pain. We compared the effect of topical ropivacaine with and without ketamine on post-tonsillectomy pain.

METHODS

Patients aged 3-7 years undergoing tonsillectomy were selected to participate in the study. Our study was performed in a randomized, placebo-controlled, double-blind manner. Patients were randomly assigned to one of two groups using computer-generated random numbers. The researchers who assessed the pain score, the caregivers, and the patient were blinded to group assignment. One group received topical ropivacaine with saline (RS group) and the other group received topical ropivacaine with 20 mg ketamine (RK group) on the tonsillar bed. Pain scores using the modified Children's Hospital of Eastern Ontario Pain Scale (mCHEOPS) at 15 min and 30 min, and at 1, 2, 4, 8, 16 and 24 h were recorded. Rescue analgesic requirement and complications were also recorded.

RESULTS

A total of 66 patients were randomly assigned to the RS group (n = 33) and the RK group (n = 33). The mCHEOPS scores were significantly lower in the RK group at 15 min (P = 0.046). The mCHEOPS scores of the two groups decreased with time, but there was no intergroup interaction. The RS group received more analgesics until 1 h after surgery and the RK group received more analgesics during 1-24 h after surgery. There were no differences in adverse outcomes.

CONCLUSIONS

Topical ropivacaine with ketamine can reduce immediate postoperative pain and analgesic requirement better than ropivacaine alone.

Adjuncts to local anaesthetics in tonsillectomy: a systematic review and meta-analysis

The infiltration of local anaesthetic agents has been shown to reduce post-tonsillectomy pain. A number of recent studies have shown that the addition of agents such as clonidine and dexamethasone improve the efficacy of nerve blocks and spinal anaesthesia. The aim of this review was to determine whether additives to local anaesthetic agents improve post-tonsillectomy outcomes. Four major databases were systematically searched for all relevant studies published up to August 2016. All study designs with a control group receiving local anaesthetic infiltration and an intervention receiving the same infiltration with an added agent were included in this review. These studies were then assessed for level of evidence and risk of bias. The data were then analysed both qualitatively and where appropriate by meta-analysis. We reviewed 11 randomised controlled trial (RCTs) that included 854 patients. Due to inconsistencies in the methods used to report outcomes, both quantitative and qualitative comparisons were required to analyse the extracted data. Overall, we found that dexamethasone, magnesium, pethidine and tramadol reduce post-operative pain and analgesia use, with dexamethasone in particular significantly reducing post-operative nausea and vomiting and magnesium infiltration significantly reducing the incidence of laryngospasm. This systematic review of RCTs provides strong evidence that the use of dexamethasone and magnesium as additives to local anaesthetics reduces post-tonsillectomy pain and analgesia requirement. There is limited evidence that pethidine and tramadol have a similar effect on pain and analgesia requirement. The studies in this pooled analysis are sufficiently strong to make a level one recommendation that the addition of magnesium to local anaesthetics reduces the incidence of laryngospasm, a potentially lethal post-operative complication. Review level of evidence: 1.

Pharmacokinetics and analgesic effectiveness of intravenous parecoxib for tonsillectomy ± adenoidectomy

BACKGROUND

Few pharmacokinetic (PK) and pharmacodynamic (PD) data exist for COX-2 selective inhibitors in children. We wished to characterize the PKPD of parecoxib and its active metabolite, valdecoxib, in this population.

METHODS

Children (n = 59) were randomized to parecoxib 0.25 mg·kg^-1 , 1 mg·kg^-1 , and 2 mg·kg^-1 during tonsillectomy ± adenoidectomy. Samples (4-6 per child) were obtained from indwelling cannula over 6 h. A second group of inpatient children (n = 15) given 1 mg·kg^-1 contributed PK data from 6 to 24 h. Pain scores and rescue medication for the first group were recorded postoperatively for up to 24 h. PK data were pooled with those (10 samples/24 h) from a published study of children (n = 38) who underwent surgery. A three-compartment parent and one-compartment metabolite model with first-order elimination was used to describe data using nonlinear mixed effects models. An E_MAX model described the relationship between dose and rescue morphine equivalents during recovery.

RESULTS

Parecoxib PK parameter estimates were CL_PARECOXIB 19.1 L·h^-1 ·70 kg^-1 , V1_PARECOXIB 4.2 L·70 kg^-1 , Q2_PARECOXIB 6.29 L·h^-1 ·70 kg^-1 , V2_PARECOXIB 130 L·70 kg^-1 , Q3_PARECOXIB 6.02 L·h^-1 ·70 kg^-1 , and V3_PARECOXIB 2.03 L·70 kg^-1 . We assumed all parecoxib was metabolized to valdecoxib with CL_VALDECOXIB 9.53 L·h^-1 ·70 kg^-1 and V_VALDECOXIB 51 L·70 kg^-1 . There was no maturation of clearance over the age span studied. There were no differences in pain scores between groups on waking, discharge, 12 h, or 24 h. There were no differences in analgesia consumption over 24 h between groups for tramadol, fentanyl, and morphine rescue use. Fentanyl and morphine consumption, expressed as morphine equivalents (0.13 mg·kg^-1 ) in the 0.25 mg·kg^-1 group, was greater than that observed in the 1 or 2 mg·kg^-1 groups (0.095 mg·kg^-1 ) in PACU.

CONCLUSIONS

Parecoxib 0.9 mg·kg^-1 in a 2-year-old, 0.75 mg·kg^-1 in a 7-year-old, and 0.65 mg·kg^-1 in a 12-year-old child achieves dose equivalence of 40 mg in a standard 70 kg person. Clearance maturation may occur in infants younger than the current cohort. Parecoxib doses above 1 mg·kg^-1 add no additional analgesia.

Treatment of Pain in Pediatric Patients

A growing body of evidence demonstrates that untreated pain is associated with adverse consequences that can compromise clinical and developmental outcomes in children but that these adverse consequences can be prevented or attenuated by appropriate analgesic therapy. Thus, effective treatment of acute pain must be a clinical priority for children of all ages. Over the past 20 years, extensive pediatric research exploring pain assessment, developmental pharmacology of analgesics, and the clinical use of analgesics has dispelled many myths and misconceptions about pain management in pediatric patients; proven that analgesics can be used safely in neonates, infants, and children; and provided a framework for the development of pediatric pain management guidelines. This article reviews guidelines recommended for managing acute pain in pediatric patients and the treatment options for children experiencing acute pain. Contemporary issues regarding acetaminophen, nonsteroidal anti-inflammatory agents, and opioids are discussed.

Does Montelukast Have an Effect on Post-tonsillectomy Pain Control in Children? A Randomized Trial Study

OBJECTIVE

Tonsillectomy surgery is associated with severe postoperative pain that usually requires analgesics including opioids. Pain control is still a big problem after tonsillectomy surgery. We aimed to evaluate the efficacy of preemptive analgesia using montelukast for pediatric post-tonsillectomy pain management. This is the first-time use of montelukast in post-tonsillectomy pain.

STUDY DESIGN

Double-blind, controlled-randomized study.

SETTINGS

University teaching and research hospital.

SUBJECTS AND METHODS

A total of 60 children, aged 5 to 15 years, American Society of Anesthesiologist class I-II, scheduled for elective tonsillectomy were enrolled in this clinical trial study. The patients were randomized into 2 groups: the montelukast group (group M, n = 30) and control group (group C, n = 30). Group M recieved an oral montelukast tablet and group C recieved placebo at 2400pm on the morning before surgery. Post-tonsillectomy pain was evaluated with the Wong-Baker FACES Scale during the 24 hours after surgery. Patients' intraoperative hemodynamic parameters and intraoperative and postoperative complications were recorded.

RESULTS

There were statistically significant differences between group C and group M for Wong-Baker FACES pain rating scale scores (P < .05). In the 24 hours after surgery, the total number of patients using rescue analgesics was higher in group C than in group M, and the difference was statistically significant (P < .001). There was no significant difference in demographic parameters (P > .05). There were no significant differences in postoperative nausea and vomiting, otalgia, trismus, fever, or halitosis between the groups (P > .05).

CONCLUSION

Preemptive montelukast can be used safely to reduce the serious pain caused by tonsillectomy in children.

The impact of clonidine on sedation after adenotonsillectomy: a prospective audit

AIMS

Clonidine may be used intraoperatively to decrease emergence delirium in children, but the drug's impact on postoperative sedation is poorly quantified.

METHODS

A prospective audit of children (≤15 years) undergoing (adeno) tonsillectomy or adenoidectomy over a period of 4 months was carried out. All children received sevoflurane for induction and maintenance of anesthesia. The use of clonidine as an adjunct was left to the discretion of the anesthesiologist. Postoperative sedation was assessed using the University of Michigan Sedation Scale (UMSS) at 30 min intervals until discharge. Arousal was characterized using a zero asymptote model. The impact of clonidine dose on half-time to an awake state after anesthesia was investigated using nonlinear mixed effects models. Survival analysis was used to explore the effect of clonidine dose on discharge time.

RESULTS

The mean age of children (n = 177) was 5.4 sd 3.3 years, range 0.8-15.0 years and weight was 23.8 SD 11.4 kg, range 10.0-76.4 kg. There were 73 children given clonidine 0.29-4.80 mcg·kg(-1) after induction. The half-time to emergence was 10.8 (95% CI 8.5, 13.2) min. Emergence half-time was increased to 15 min with clonidine 0.5 mcg·kg(-1), 20 min with clonidine 1.5 mcg·kg(-1), 25 min with clonidine 2 mcg·kg(-1) and 65 min with clonidine 4 mcg·kg(-1). Clonidine doses 0.5-3 mcg·kg(-1) did not affect hospital discharge time.

CONCLUSIONS

Clonidine administered intraoperatively for (adeno) tonsillectomy or adenoidectomy prolonged emergence from anesthesia. Doses of 0.5-3 mcg·kg(-1) caused greater sedation in the postanesthesia care unit but did not impact on hospital discharge times.

Ketamine peritonsillar infiltration during tonsillectomy in pediatric patients: An updated meta-analysis

OBJECTIVES

Peri-operative ketamine peritonsillar infiltration in children can reduce the incidence of postoperative nausea and vomiting (PONV), but its postoperative analgesic time is short. A previous meta-analysis in 2011 was inconclusive due to insufficient data. Consequently, we updated the meta-analysis to verify the role of ketamine peritonsillar infiltration for tonsillectomy in pediatric patients.

METHODS

Ten randomized controlled trials with a total of 522 cases were included. Pain intensity was measured by standard modified CHEOPS score.

RESULTS

The pain scores of ketamine group at 30 min and 60 min were significantly lower than placebo group after surgery [weighted mean difference (WMD) -1.20, 95% CI -2.20 to -0.19, P=0.02; WMD -1.71, 95% CI -2.12 to -0.22, P=0.02]. Analgesic requirement in ketamine group were less than placebo group [risk ratio (RR) 0.51, 95% CI 0.26-0.97; P=0.04]. Moreover, the incidence of PONV was lower in ketamine group. (RR 0.73, 95% CI 0.54-0.97; P=0.03). However, there were no differences between these two groups in operation time, anesthesia time, first analgesic time and pain score at 120 min.

CONCLUSIONS

Compared to placebo, ketamine peritonsillar infiltration can relieve postoperative pain within one hour but not at 120 min and reduces analgesic requirement and incidence of PONV. Moreover, there was no difference in the first analgesic time.

Incidence and risk factors of postoperative nausea and vomiting in patients with fentanyl-based intravenous patient-controlled analgesia and single antiemetic prophylaxis

PURPOSE

We evaluated the incidence and risk factors of postoperative nausea and vomiting (PONV) in patients with fentanyl-based intravenous patient-controlled analgesia (IV-PCA) and single antiemetic prophylaxis of 5-hydroxytryptamine type 3 (5 HT₃)-receptor antagonist after the general anesthesia.

MATERIALS AND METHODS

In this retrospective study, incidence and risk factors for PONV were evaluated with fentanyl IV-PCA during postoperative 48 hours after various surgeries.

RESULTS

Four hundred-forty patients (23%) of 1878 had showed PONV. PCA was discontinued temporarily in 268 patients (14%), mostly due to PONV (88% of 268 patients). In multivariate analysis, female, non-smoker, history of motion sickness or PONV, long duration of anesthesia (>180 min), use of desflurane and intraoperative remifentanil infusion were independent risk factors for PONV. If one, two, three, four, five, or six of these risk factors were present, the incidences of PONV were 18%, 19%, 22%, 31%, 42%, or 50%. Laparoscopic surgery and higher dose of fentanyl were not risk factors for PONV.

CONCLUSION

Despite antiemetic prophylaxis with 5 HT₃-receptor antagonist, 23% of patients with fentanyl-based IV-PCA after general anesthesia showed PONV. Long duration of anesthesia and use of desflurane were identified as risk factors, in addition to risk factors of Apfel's score (female, non-smoker, history of motion sickness or PONV). Also, intraoperative remifentanil infusion was risk factor independent of postoperative opioid use. As the incidence of PONV was up to 50% according to the number of risk factors, risk-adapted, multimodal or combination therapy should be applied.

Ropivacaine plus dexamethasone infiltration reduces postoperative pain after tonsillectomy and adenoidectomy

OBJECTIVE

To compare the effect of ropivacaine plus dexamethasone and ropivacaine alone as infiltration anesthesia on postoperative pain, nausea and vomiting, and oral intake in children after tonsillectomy and adenoidectomy.

METHODS

Two hundred pediatric patients scheduled for tonsillectomy and adenoidectomy were prospectively enrolled and randomly placed in a ropivacaine with dexamethasone group (RD) or a ropivacaine alone group (R). Treatment for both groups was administered by local infiltration, and pain scores were recorded at various intervals. Primary outcomes were pain scores recorded 4-24h postoperation. Secondary outcomes included time to the first administration of analgesic and total consumption of analgesics for all children, time to first water request, first oral intake, incidence of nausea or vomiting, and time to discharge.

RESULTS

From postoperative hours 4-24, children in the RD group had lower pain scores than children in the R group (P < 0.05). Total fentanyl consumption was significantly decreased in the RD group compared to the R group (50.9 ± 9.3 vs. 103.9 ± 11.5 μg, P < 0.001). The time to first water request and first oral intake were significantly shorter in the RD group [(40 min (27-64) vs. 64 min (43-89); P < 0.001) and (54 min (40-91) vs. 85 min (67-127); P < 0.001), respectively]. Oral intake was significantly improved, and the incidence of nausea and vomiting were reduced in the RD group (P < 0.05). The time to discharge was shorter in the RD group when compared with the R group (9.06 ± 0.89 d vs. 7.05 ± 0.71 d; P < 0.001).

CONCLUSIONS

Ropivacaine plus dexamethasone infiltration effectively lowers pain, improves oral intake, lowers postoperative nausea and vomiting, and decreases the time to discharge.

Comparison of topical tramadol and ketamine in pain treatment after tonsillectomy

OBJECTIVES/AIM

The primary objective of this study is to evaluate the effects of topically applied ketamine or tramadol on early postoperative pain scores in children undergoing tonsillectomy. The secondary aim of the study is to assess nausea, vomiting, difficulty in swallowing, and sore throat characteristics of the patients.

BACKGROUND

Tonsillectomy surgery is frequently associated with postoperative pain, which usually requires substantial consumption of analgesics including opioids. Safe and effective post-tonsillectomy pain control is still a clinical dilemma, in spite of the use of various surgical and anesthetic techniques.

METHODS

A total of 60 children, aged between 4 and 10 years, scheduled for tonsillectomy, were randomly assigned to one of three groups. Study drugs were administered to both tonsillar fossae for 5 min. In 5 ml artificial saliva, Group K (n = 20) received 0.4 ml (20 mg) ketamine and Group T (n = 20) received 0.8 ml tramadol HCl solution. Group C (n = 20) received only 5 ml saline as a control. Ramsay Sedation Scale and FACES PRS Score, nausea, vomiting, difficulty in swallowing, and sore throat were evaluated.

RESULTS

There was no difference among the groups in terms of baseline characteristics, including age, sex, and ASA profile (P > 0.05 for all). Systolic blood pressure, diastolic blood pressure, mean blood pressure, heart rate, respiratory rate, and saturation of peripheral oxygen (SpO2 ) values were not significantly different among the groups in all time points (P > 0.05 for all). There was a statistically significant difference among the groups according to Ramsay Sedation Scales in 40th minute (P < 0.001). There were statistically significant differences among the groups in terms of Wong-Baker FACES Pain Rating Scale Score in all time points (P < 0.004 for all). There was a statistically significant difference among the groups in terms of rescue analgesia necessity in 5th and 10th minute (P < 0.001 and P = 0.003). There was a statistically significant difference among the groups in terms of sore throat in 5th and 10th minute (P < 0.001 for both). Neither rescue analgesia necessity nor sore throat characteristics was different between the Group T and Group K in all time points.

CONCLUSION

Topical tramadol and ketamine seem to be safe, effective, and easy analgesic approach for decreasing tonsillectomy pain.

A prospective, randomized, double blind and placebo-control study comparing the additive effect of oral midazolam and clonidine for postoperative nausea and vomiting prophylaxis in granisetron premedicated patients undergoing laparoscopic cholecystecomy

Background:

Reduction of postoperative nausea and vomiting (PONV) continues to be a major challenge in perioperative care in spite of introduction of newer antiemetics with better efficacy and safety profiles. Therefore, we evaluated the additive effect of oral midazolam and clonidine for PONV prophylaxis in granisetron premedicated patients undergoing laparoscopic cholecystectomy.

Materials and Methods:

In a prospective, randomized fashion, 120 selected cases were randomized into three groups: I, II or III to receive a tablet of midazolam (15 mg, n = 36), clonidine (150 mcg, n = 40), or glucose as placebo (5 g, n = 44) orally, 1 h before anesthesia. Occurrence of PONV along with need for rescue antiemetic during the first postoperative day was compared between groups as a primary outcome.

Results:

Episodes of PONV reduced significantly in Group II (15%) as compared to group I and III (22.2%, 59%) at various time points during the period of observation (P = 0.002). Need for rescue antiemetic was significantly lower in group I (13.88%) and II (5%) as compared to group III (52.27%, P < 0.001).

Conclusion:

Oral clonidine is better adjuvant for PONV prophylaxis, as compared to midazolam, in granisetron premedicated patients undergoing laparoscopic cholecystectomy.

My child is unique; the pharmacokinetics are universal

The pharmacokinetic (PK) parameters that are important for dosing (e.g., clearance and volume) are well known. They are used in universal mathematical formulae that describe the time course of drug concentration. Additional formulae can be used to describe major covariate effects in children, such as size and maturation. PK parameters describing the time-concentration profile of a drug after administration are those for a typical individual in a population. These parameters are associated with variability. Further, any one individual may not be typical of the population studied. While size and maturation are two important considerations in children and assist with dosing estimation, there are also a number of additional PK covariates (e.g., organ function, disease, drug interactions, pharmacogenetics), and identifying these sources of variability allows us to individualize drug dose. Pharmacology is not simply an application of PK, and determinants of drug dose also require an understanding of the variability associated with pharmacodynamic response and a balancing of beneficial effects against unwanted effects. Each child is unique in this respect.

Analgesic efficacy of topical tramadol in the control of postoperative pain in children after tonsillectomy

PURPOSE

Pain control after tonsillectomy is still a controversial issue. Topical approaches have the advantage of pain control with good patient acceptability. Therefore, this study was conducted to evaluate the effects of topical tramadol on postoperative pain and morbidity in children undergoing tonsillectomy.

METHODS

A prospective, randomized, double-blind, controlled clinical study was designed. Forty children aged between 4 and 15 years, ASA I-II, scheduled for elective tonsillectomy and/or adenoidectomy were randomized into two groups. For patients in Group T (n = 20) swabs soaked with 2 mg/kg tramadol diluted in 10 ml saline were applied to both of their tonsillar fossa for 5 min; in the control group (n = 20) swabs soaked with 10 ml saline were applied. Postoperative pain scores, bleeding, nausea, vomiting, abdominal discomfort, constipation, pain in the throat, painful swallowing, fever, otalgia, trismus, and halitosis were recorded at the first, fifth, thirteenth, seventeenth, twenty-first, and twenty-fourth postoperative hours and the week after tonsillectomy.

RESULTS

Pain scores were found to be significantly lower at the 21st hour and on postoperative day seven in the tramadol group compared with the control group (p < 0.05). Mean daily pain scores ranged from Day 1: 0.34 (±0.21) to Day 7: 0.11 (±0.08) in the tramadol group and Day 1: 0.53 (±0.14) to Day 7: 0.42 (±0.15) in the control group. There were no significant differences in morbidity between the groups (p > 0.05).

CONCLUSION

Topical 5% tramadol with its local anesthetic effect seems to be an easy, safe, and comfortable approach for pain management in children undergoing tonsillectomy.

A national survey of the anesthetic management of tonsillectomy surgery in children

BACKGROUND

Tonsillectomy in children is a common procedure; however, there appears to be a significant degree of variability in anesthetic management. Thus far, there has been no large national survey looking at the perioperative care of these children.

OBJECTIVES

We conducted a national survey with the aim of determining what represents common practice in the perioperative management of children undergoing tonsillectomy surgery. We compared the respondents' management against evidence-based practice.

METHODS

The survey took the form of a questionnaire, which was sent to members of The Association of Paediatric Anaesthetists (APAGBI) and to Royal College tutors. The questionnaire was sent in paper format to the College Tutors and in digital format to APAGBI members. Emphasis was placed upon preoperative preparation, induction technique, airway management, analgesia, postoperative nausea and vomiting strategy, fluid management and emergence from anesthesia.

RESULTS

Responses were obtained from 173 individuals representing a broad cross-section of anesthetists from teaching and district general hospitals. Findings are as follows: the application of topical anesthetic cream is commonplace (93%), with Ametop being the primary preparation used; the intravenous route was preferred to induce anesthesia; most practitioners intubate the trachea to maintain the airway during anesthesia (79%); a muscle relaxant was employed to assist intubation of the trachea in 47% of respondents and the routine use of suxamethonium was reported to be uncommon (9%); the administration of prophylactic ondansetron and dexamethasone was reported by 79% and 70% of respondents respectively; and nonsteroidal anti-inflammatory drugs (NSAIDs) are used by 77% of individuals either pre-emptively or during the intraoperative period.

CONCLUSIONS

Whilst there is individual variability in the management of these cases, the majority of anesthetists prefer the intravenous route for induction of anesthesia, after application of topical anesthetic cream. It is routine practice to intubate the trachea, administer paracetamol, NSAIDs, strong opiates and antiemetics.

Subhypnotic propofol infusion plus dexamethasone is more effective than dexamethasone alone for the prevention of vomiting in children after tonsillectomy

BACKGROUND

Postoperative vomiting (POV) is a common complication after tonsillectomy. Dexamethasone is known to decrease postsurgical vomiting. In this study, we compared the effects of dexamethasone alone to dexamethasone plus propofol on postoperative vomiting in children undergoing tonsillectomy.

METHODS

In a randomized double-blinded study, we evaluated 80 healthy children, aged 4-12 years, who underwent tonsillectomy with or without adenoidectomy. After anesthesia was induced by inhalation of sevoflurane, 0.15 mg x kg(-1) dexamethasone and 2 microg x kg(-1) fentanyl was administered i.v. to all patients. The patients in the dexamethasone plus propofol group received 1 mg x kg(-1) propofol before intubation and continuously after intubation at a rate of 20 microg x kg(-1) x min(-1) until the surgery was completed. Data for postoperative vomiting were grouped into the following time periods: 0-4 and 4-24 h. Data were analyzed using a Student's t-test and chi-squared analysis.

RESULTS

The percentage of patients exhibiting a complete response (defined as no retching or vomiting for 24 h) increased from 37.5% in the dexamethasone-alone group to 75% in the dexamethasone plus propofol group (P = 0.001). Twenty-two patients (55%) in the dexamethasone-alone and nine patients (22.5%) in the dexamethasone plus propofol groups experienced vomited during 0-4 h (P = 0.003). Eight patients in the dexamethasone-alone group and three patients in the dexamethasone plus propofol group received ondansetron as a rescue antiemetic during the postoperative period.

CONCLUSION

For children undergoing tonsillectomy, intraoperative subhypnotic propofol infusion combined with dexamethasone treatment provides a better prophylaxis against postoperative vomiting than does dexamethasone alone.

Topical ketamine and morphine for post-tonsillectomy pain

BACKGROUND AND OBJECTIVES

Tonsillectomy is frequently associated with postoperative pain of considerable duration, which is usually accompanied by the substantial consumption of both opioid and non-opioid analgesics. Despite the use of different surgical and anaesthetic techniques in the search for safe and effective post-tonsillectomy pain relief, this problem remains a clinical dilemma. The aim of the current study was to evaluate the potential effects of topically administered ketamine and morphine by an oral rinse into the tonsillar fossae.

METHODS

In all, 60 children, 15 for each group, aged between 3 and 12 yr scheduled for tonsillectomy were randomly assigned to one of four groups. Study drugs were administered to both tonsillar fossae for 5 min. Group K received 0.4 mL (20 mg) ketamine in 10 mL artificial saliva, Group KM received 0.4 mL (20 mg) ketamine + 5 mL (20 mg) 4 per thousand morphine aqueous solution in 5 mL artificial saliva, Group M received 5 mL (20 mg) 4 per thousand morphine aqueous solution in 5 mL artificial saliva, Group C received only 10 mL artificial saliva. Postoperative pain, nausea, vomiting, sedation and bleeding were evaluated.

RESULTS

Pain scores were higher in the control group at arrival in the recovery ward (P < 0.05). Morphine and ketamine groups had longer effective analgesia time than the morphine + ketamine and control groups. The 24-h analgesic consumption was significantly higher in the control group.

CONCLUSION

Topical ketamine and morphine seems to be a safe and easy analgesic approach for decreasing adenotonsillectomy pain.

Population clinical pharmacology of children: modelling covariate effects

INTRODUCTION

Population modelling using mixed effects models provides a means to study variability in paediatric drug responses among individuals representative of those in whom the drug will be used clinically.

DISCUSSIONS

Explanatory covariates explain the predictable part of the between-individual variability. Growth and development are two major aspects of children not seen in adults. These aspects can be investigated by using size and age as covariates. Problems attributable to co-linearity can be approached by using size as the first covariate. Size standardisation is achieved using allometric scaling, a mechanistic approach that has a strong theoretical and empirical basis. Age is used to describe the maturation of clearance. The quantitative models (linear, exponential, first-order, variable slope sigmoidal) used to describe this maturation process vary depending on the span of the ages under investigation. Measures of response are not always straightforward and can be more difficult to quantify in children.

CONCLUSION

Covariate investigation in children is improving the understanding of developmental aspects of drug disposition and effects in the paediatric population, ultimately leading to more effective use of medications.

Prophylaxis of postoperative vomiting in children undergoing tonsillectomy: a systematic review and meta-analysis

Postoperative vomiting (POV) remains one of the commonest causes of significant morbidity after tonsillectomy in children. A variety of prophylactic anti-emetic interventions have been reported, but there has only been a limited systematic review in this patient group. A systematic search was performed by using Cochrane Controlled Trials Register, MEDLINE and EMBASE to identify double-blind, randomized, placebo-controlled trials of prophylactic anti-emetic interventions in children undergoing tonsillectomy, with or without adenoidectomy. The outcome of interest was POV in the first 24 h. Summary estimates of the effect of each prophylactic anti-emetic strategy were derived using fixed effect meta-analysis. Where appropriate, dose-response effects were estimated using logistic regression and 22 articles were identified. Good evidence was found for the prophylactic anti-emetic effect of dexamethasone [odds ratio (OR) 0.23, 95% CI 0.16-0.33], and the serotinergic antagonists ondansetron (OR 0.36, 95% CI 0.29-0.46), granisetron (OR 0.11, 95% CI 0.06-0.19), tropisetron (OR 0.15, 95% CI 0.06-0.35) and dolasetron (OR 0.25, 95% CI 0.1-0.59). Metoclopramide was also found to be efficacious (OR 0.51, 95% CI 0.34-0.77). There is not sufficient evidence to suggest that dimenhydrinate, perphenazine or droperidol, in the doses studied, are efficacious, nor were gastric aspiration or acupuncture. In conclusion, dexamethasone and the anti-serotinergic agents appear to be the most effective agents for the prophylaxis for POV in children undergoing tonsillectomy.

Schmerztherapie bei ambulanten Operationen im Kindesalter

A number of surgical procedures for pediatric patients can be suitably performed in an outpatient setting. The advantages are impressive: reduced costs, lower rate of infection, avoidance of hospitalization with the inherent psychological stress, and timely return of the patients to their familiar home environment. An essential feature of the quality of outpatient surgery is the efficacy of the perioperative pain therapy for which a multimodal approach has proven to be very effective: workflow tailored to children's needs, ambiance appropriate for children, and pharmacological analgesia. In the preliminary counseling session it is imperative that parents and children receive detailed information on procedures (role playing, modeling). Associated unpleasant factors prior to induction of anesthesia should be avoided. The primary element of pharmacological analgesia is regional anesthesia; additional options are paracetamol, nonsteroidal antirheumatic agents (be aware of the highest dosages!), and opioids. When opioids are employed, care should be taken that monitoring standards in the recovery room are not lowered and include pulsoxymetry. Because of the clearly elevated rate of postoperative nausea and vomiting related to perioperative administration of opioids, the lower dosage level should be chosen. This article presents concepts of perioperative analgesia.

An evaluation of pain and postoperative nausea and vomiting following the introduction of guidelines for tonsillectomy

BACKGROUND

Tonsillectomy and adenotonsillectomy have a high incidence of postoperative pain, and postoperative nausea and vomiting (PONV). Pain is traditionally controlled with morphine but this increases the risk of PONV and may cause respiratory depression. Antiemetics reduce PONV but their routine use has been questioned on safety grounds.

METHOD

After determining the current anesthetic management of elective tonsillectomy and adenotonsillectomy patients in our hospital, guidelines were developed to avoid the routine use of morphine and antiemetics. The effect on pain and PONV was then evaluated over a 3 month period. Postoperative pain was scored using the Oucher visual analog scale and nausea scored using a five point scale.

RESULTS

We analysed 34 cases to determine our current practice and 37 cases to evaluate the effect of introducing guidelines. Postguidelines, the median Oucher pain score at 4 h was 10, and at 8, 12, 16 h was zero. Despite receiving no antiemetics, only two children vomited (5%) after introduction of guidelines.

CONCLUSION

Guidelines which use a combination of paracetamol, nonsteroidal anti-inflammatory drugs and fentanyl, provide excellent analgesia with minimal PONV after elective tonsillectomy and adenotonsillectomy. As a result the routine use of morphine and antiemetics can be avoided.

Day stay pediatric tonsillectomy--a safe procedure

OBJECTIVE

There is a controversy about day stay pediatric tonsillectomy in the UK and Australia. New Zealand has a similar health structure and we wished to compare day stay tonsillectomy from our hospital with those reported from other centers.

METHODS

We performed a prospective audit of day stay tonsillectomy to determine conversion to hospital admission rate and the incidence of postoperative hemorrhage.

RESULTS

There were 4850 paediatric tonsillectomies performed with 80% of them as day stay procedures over a 9-year study period (1993-2002) in a university-affiliated tertiary children's hospital. The primary postoperative hemorrhage rate (within 24h of surgery) was 0.9% (CI 0.68-1.22%) and 83% occurred within the mandatory 4h postoperative observation period. Primary hemorrhage requiring re-operation to achieve hemostasis occurred in 18 children (0.37%, CI 0.2-0.54%). No child with a primary hemorrhage who presented after discharge following day stay surgery required re-operation or blood transfusion. Day stay surgery was planned in 4041 children and 4.7% (CI 4.1-5.4%) required conversion to hospital admission. Postoperative vomiting was the most common indication for conversion (2.65%, CI 2.2-3.1%), while hemorrhage contributed only 0.95% (CI 0.64-1.24%).

CONCLUSIONS

This study was performed in a health system similar to that of Australia and the UK. Complication and conversion rates are similar to those reported in North American centers. Pediatric day stay tonsillectomy is a safe procedure when performed with strict preoperative criteria, trained day stay unit (DSU) staff, and with in-patient facilities on site.

Preemptive diclofenac reduces morphine use after remifentanil-based anaesthesia for tonsillectomy

BACKGROUND

We investigated the effect of preincisional rectal diclofenac on pain scores and postoperative morphine requirements of children undergoing tonsillectomy after remifentanil-propofol anaesthesia in a randomized clinical trial.

METHODS

Induction and maintenance of anaesthesia were with remifentanil and propofol. Forty children were randomly assigned into two groups before incision. The diclofenac group (n=20) received diclofenac suppositories (approximately 1 mg x kg(-1)) and the control group (n=20) received no treatment. Following discontinuation of remifentanil, patient-controlled analgesia (PCA) with morphine (a loading dose 50 micro g x kg(-1), a background infusion 4 micro g x kg(-1) x h(-1) and a demand dose 20 micro g x kg(-1) with 5-min intervals) was started. We assessed pain score [verbal analogue scales (VAS), 0-10] and sedation level at 5-min intervals and recorded the total morphine consumption of the first hour in the PACU. Patients were discharged to the ward with a new PCA morphine programme (a demand dose 20 micro g.kg-1 with a lockout time of 30 min, for 4 h), and total morphine consumption was recorded.

RESULTS

The mean VAS score of the diclofenac group was significantly lower than the control group on arrival in the PACU (2.85 +/- 0.77, 7.60 +/- 0.83, respectively, P < 0.01) and it remained significantly lower in the PACU stay of the children. The mean total morphine consumption of the diclofenac group was less than the control group in the PACU (130.33 +/- 11.26 and 169.92 +/- 9.22, respectively, P=0.012) and the ward (50.80 +/- 11.38 and 87.77 +/- 10.55, respectively, P=0.021).

CONCLUSIONS

Preemptive diclofenac given rectally reduced pain intensity and morphine requirements of children anaesthetized with remifentanil for tonsillectomy.

The effect of remifentanil or fentanyl on postoperative vomiting and pain in children undergoing strabismus surgery

Postoperative vomiting (POV) after strabismus surgery in children results in discomfort and prolonged hospital stays. Opioids increase the incidence of POV. Remifentanil has a context-sensitive half-life of 3 to 4 min, and how this short half-life influences POV in those patients is unknown. We conducted a prospective, double-blinded study in 81 ASA status I or II children from 2 to 12 yr of age undergoing elective strabismus surgery under general anesthesia. Patients were randomized to receive either remifentanil (bolus 1 microg/kg; infusion 0.1-0.2 microg x kg(-1) x min(-1)) or fentanyl (2 microg/kg, and 1 microg/kg every 45 min). POV episodes were recorded for 25 h. Pain scores were obtained by using an objective pain scale for 60 min during recovery. The number of patients who experienced POV did not differ significantly between groups (49% vs 48%). However, in the Remifentanil group, POV episodes were significantly less frequent (0.95 vs 2.2 episodes). In contrast, fentanyl was associated with lower pain scores during the first 30 min of recovery. We conclude that children undergoing strabismus surgery under balanced anesthesia with remifentanil, compared with fentanyl, showed less frequent POV. However, early postoperative analgesia was better with fentanyl.

IMPLICATIONS

Opioids increase the incidence of postoperative vomiting (POV). Remifentanil is characterized by the shortest half-life of all opioids used in anesthetic practice. Therefore, we studied the effect of remifentanil on POV compared with the longer-acting opioid fentanyl in children undergoing strabismus surgery.

Cisapride does not prevent postoperative vomiting in children

The peripherally acting prokinetic drug cisapride can overcome opioid-induced gastrointestinal paresis and may thereby eliminate a stimulus for postoperative vomiting. We conducted a prospective, randomized, double-blinded, controlled trial of 96 children undergoing inguinal surgery to determine whether cisapride would reduce the incidence of postoperative vomiting after general anesthesia supplemented with morphine. Group C1 patients (n = 38) received cisapride 0.3 mg/kg orally 1 h before surgery and placebo 6 h later, Group C2 (n = 28) received cisapride both before and after surgery, and Group P (n = 30) received placebo. Mean age (5.0 +/- 2.7 yr) and weight (21.0 +/- 8.6 kg), median pain scores and parent satisfaction scores, and incidence of rescue analgesic administration were similar across groups. Contrary to our hypothesis, incidences of postoperative vomiting in the hospital (32% vs 20%, P = 0.33) and at home (53% vs 46%, P = 0.33) did not vary by treatment group (with [C1 and C2] and without [P] cisapride, respectively). There was a trend toward more severe postoperative vomiting (three or more episodes) in children who received cisapride versus those who did not, both in hospital (6% vs 0%, P = 0.3) and at home (22% vs 8%) (P = 0.13). We conclude that cisapride does not prevent postoperative vomiting in this patient population and speculate that factors other than reduced gastrointestinal motility associated with general anesthesia and opioids are more important determinants of postoperative vomiting.

IMPLICATIONS

Cisapride does not prevent postoperative vomiting in children and may increase its severity.

Pharmacologic rationale for anesthetic agents in ambulatory practice

Patients undergoing surgery in the ambulatory setting require anesthetic agents that expedite postoperative recovery, minimize adverse side effects, and contribute to patient satisfaction. The newer anesthetic agents that are currently used in today's practice offer the flexibility needed to provide anesthesia care for a wide variety of diagnostic and therapeutic procedures performed on an outpatient basis. It is important for the perianesthesia nurse to be familiar with the anesthetic agents used in the operating room to fully understand the influence of these drugs on the patient's recovery process. The role of the perianesthesia nurse is vital in assessing the residual effects of the anesthetic agents and instituting proper nursing interventions during the patient's postanesthesia experience. This article focuses on the rationale for the use of a variety of anesthetic and related agents necessary for the provision of ambulatory anesthesia. The commonly used agents used in ambulatory anesthesia care and their influences on the continuum of care is reviewed.