Nonsteroidal anti-inflammatory drugs for postoperative pain: a focus on children

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.

Cerebrospinal Fluid Distribution of Ketoprofen after Intravenous Administration in Young Children

OBJECTIVE

The purpose of this study was to evaluate the cerebrospinal fluid (CSF) distribution of an NSAID, ketoprofen, in children. Ketoprofen concentrations were determined from the CSF, plasma and protein-free plasma samples.

METHODS

Children (n = 21), aged 13-94 months, were given intravenous ketoprofen (1 mg/kg) prior to surgery under spinal anaesthesia. Single venous blood and CSF samples from each patient were collected simultaneously 7-67 minutes after the drug administration. Ketoprofen concentrations in the samples were determined using gas chromatography-mass spectrometry.

RESULTS

Ketoprofen entered the CSF and was detectable in all samples. However, CSF delivery was limited; the ratio of ketoprofen concentration in CSF to plasma remained below 0.006 at all times. Ketoprofen was highly bound (> 98%) to plasma proteins. The free ketoprofen fraction was not in equilibrium with the CSF, and no clear peak drug concentration in the CSF was observed.

CONCLUSION

This study shows that ketoprofen is able to enter the CSF of children, which enables central analgesic effects of ketoprofen. However, the slow distribution of ketoprofen into the CSF and the apparently low absolute concentrations has to be taken into account when central analgesic effects are desired.

Postoperative Schmerztherapie nach Tonsillektomie im Kindesalter

OBJECTIVE

We investigated the efficacy and side-effects of a concept for pain therapy after tonsillectomy in children.

PATIENTS AND METHODS

A total of 100 children aged between 6 and 14 years were treated according to the following protocol for pain therapy after tonsillectomy: after induction of anaesthesia the children received 35-40 mg/kg acetaminophen rectally and 0.1 mg/kg piritramide i.v.. Additionally, boluses of 0.05 mg/kg pitritramide i.v. were allowed in the recovery room and 2 doses of 20 mg/kg acetaminophen were given rectally every 6 h on the day of surgery. On the following day the children received 30 mg/kg acetaminophen 3 times per day and from the second postoperative day onwards 1 mg/kg diclofenac was given 3 times a day. The rescue therapy was 5 mg/kg metamizol orally. The severity of the postoperative pain was evaluated by a visual pain scale (VAS) (0-100), side-effects such as vomiting and postoperative haemorrhage were documented. The Friedman test was used for testing the time course of pain intensity.

RESULTS

The median of the VAS was 42 on the day of surgery, 35 on the first postoperative day and fell continuously to 10 by the 6th postoperative day. The decrease of pain severity was statistically significant (p <0.05). A rescue therapy was necessary in 6 patients on the day of surgery and in 9 patients on the first postoperative day. 7 patients suffered a postoperative haemorrhage, 4 out of the 7 needed a surgical revision and 2 out of 100 patients vomited.

CONCLUSION

We conclude that this protocol for pain therapy after tonsillectomy was effective. The incidence of postoperative haemorrhage and vomiting was low.

Analgesia and anesthesia for neonates: Study design and ethical issues

OBJECTIVE

The purpose of this article is to summarize the clinical, methodologic, and ethical considerations for researchers interested in designing future trials in neonatal analgesia and anesthesia, hopefully stimulating additional research in this field.

METHODS

The MEDLINE, PubMed, EMBASE, and Cochrane register databases were searched using subject headings related to infant, newborn, neonate, analgesia, anesthesia, ethics, and study design. Cross-references and personal files were searched manually. Studies reporting original data or review articles related to these topics were assessed and critically evaluated by experts for each topical area. Data on population demographics, study characteristics, and cognitive and behavioral outcomes were abstracted and synthesized in a systematic manner and refined by group members. Data synthesis and results were reviewed by a panel of independent experts and presented to a wider audience including clinicians, scientists, regulatory personnel, and industry representatives at the Newborn Drug Development Initiative workshop. Recommendations were revised after extensive discussions at the workshop and between committee members.

RESULTS

Designing clinical trials to investigate novel or currently available approaches for analgesia and anesthesia in neonates requires consideration of salient study designs and ethical issues. Conditions requiring treatment include pain/stress resulting from invasive procedures, surgical operations, inflammatory conditions, and routine neonatal intensive care. Study design considerations must define the inclusion and exclusion criteria, a rationale for stratification, the confounding effects of comorbid conditions, and other clinical factors. Significant ethical issues include the constraints of studying neonates, obtaining informed consent, making risk-benefit assessments, defining compensation or rewards for participation, safety considerations, the use of placebo controls, and the variability among institutional review boards in interpreting federal guidelines on human research. For optimal study design, investigators must formulate well-defined study questions, choose appropriate trial designs, estimate drug efficacy, calculate sample size, determine the duration of the studies, identify pharmacokinetic and pharmacodynamic parameters, and avoid drug-drug interactions. Specific outcome measures may include scoring on pain assessment scales, various biomarkers and their patterns of response, process outcomes (eg, length of stay, time to extubation), intermediate or long-term outcomes, and safety parameters.

CONCLUSIONS

Much more research is needed in this field to formulate a scientifically sound, evidence-based, and clinically useful framework for management of anesthesia and analgesia in neonates. Newer study designs and additional ethical dilemmas may be defined with accumulating data in this field.

Non-steroidal anti-inflammatory drugs and perioperative bleeding in paediatric tonsillectomy

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used for pain relief following tonsillectomy in children. However, as they inhibit platelet aggregation and prolong bleeding time, they could cause increased perioperative bleeding. The overall risk remains unclear.

OBJECTIVES

The primary objective of this review was to assess the effects of NSAIDs on bleeding for paediatric tonsillectomy. There is good evidence (Kokki 2003; Romsing 1997) to show that NSAIDs are effective analgesics in children. It was not the remit of our review to question this, but rather to assess the risk of bleeding when NSAIDs are used for pain relief following paediatric tonsillectomy.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 3, 2004); MEDLINE (inception until August 2004); EMBASE (from inception until August 2004), Current Problems (produced by the UK Medicines Control Agency); MedWatch (produced by the US Food and Drug Administration) and the Australian Adverse Drug Reactions Bulletin in December 2001. The Cochrane Anaesthesia Review Group's handsearch co-ordinator performed handsearching as required. We also contacted manufacturers and researchers in the field.

SELECTION CRITERIA

We included randomized controlled trials assessing NSAIDs in children up to and including 16 years of age, undergoing elective tonsillectomy or adenotonsillectomy.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted the data. We contacted study authors where necessary for additional information. We also collected information on adverse effects from the trials.

MAIN RESULTS

We included 13 trials involving 955 children. All included trials compared NSAIDs with other analgesics or placebo and looked at bleeding requiring surgical intervention. NSAIDs did not significantly alter number of perioperative bleeding events requiring surgical intervention; Peto odds ratio 1.46 (95% confidence interval 0.49 to 4.40). Seven trials involving 471 children looked at bleeding not requiring surgical intervention. NSAIDs did not significantly alter number of perioperative bleeding events not requiring surgical intervention; Peto odds ratio 1.23 (95% confidence interval 0.44 to 3.43). Ten trials involving 837 children looked at post-operative nausea and vomiting. There was less nausea and vomiting when NSAIDs were used as part of the analgesic regime, compared to when NSAIDs were not used; Odds ratio 0.40 (95% confidence interval 0.23 to 0.72).

AUTHORS' CONCLUSIONS

NSAIDs did not cause any increase in bleeding requiring a return to theatre. There was significantly less nausea and vomiting when NSAIDs were used compared to alternative analgesics.

Proniosomes as a drug carrier for transdermal delivery of ketorolac

Niosomes are nonionic surfactant vesicles that have potential applications in the delivery of hydrophobic and hydrophilic drugs. Permeation of a potent nonsteroidal anti-inflammatory, ketorolac, across excised rabbit skin from various proniosome gel formulations was investigated using Franz diffusion cells. Each of the prepared proniosomes significantly improved drug permeation and reduced the lag time (P<0.05). Proniosomes prepared with Span 60 provided a higher ketorolac flux across the skin than did those prepared with Tween 20 (7- and 4-fold the control, respectively). A change in the cholesterol content did not affect the efficiency of the proniosomes, and the reduction in the lecithin content did not significantly decrease the flux (P>0.05). The encapsulation efficiency and size of niosomal vesicles formed by proniosome hydration were also characterized by specific high performance liquid chromatography method and scanning electron microscopy. Each of the prepared niosomes achieved about 99% drug encapsulation. Vesicle size was markedly dependent on the composition of the proniosomal formulations. Proniosomes may be a promising carrier for ketorolac and other drugs, especially due to their simple production and facile up.

Ketorolac after congenital heart surgery: does it increase the risk of significant bleeding complications?

BACKGROUND

The routine use of ketorolac after congenital heart surgery in infants and children is limited by concerns for postoperative bleeding complications. The object of this study was to determine if the use of ketorolac is associated with an increased risk of significant postoperative bleeding after congenital heart surgery in infants and children.

METHODS

A retrospective chart review was performed. The exposure of interest was postoperative use of ketorolac after congenital heart surgery in infants and children. The outcome measured was postoperative bleeding requiring surgical exploration. The patients who received ketorolac were compared with an age- and diagnosis-matched comparison group who did not receive ketorolac.

RESULTS

Records of 842 infants and children who underwent congenital heart surgery between July 2001 and October 2002 were reviewed. 94 (11.1%) patients were treated with ketorolac postoperatively. The comparison group consisted of 94 matched subjects selected from the patients that did not receive ketorolac. The mean age of patient in the ketorolac group was 8.5 (+/-6.1) years. No (0%) patients in the ketorolac group and four (4.2%) patients in the nonketorolac group developed postoperative bleeding requiring surgical exploration. The relative risk for postoperative bleeding that required surgical exploration in the ketorolac group compared with the nonketorolac group was 0.2 (95% CI 0.02-1.67).

CONCLUSIONS

The use of ketorolac after congenital heart surgery in infants and children does not significantly increase the risk of bleeding complications requiring surgical exploration.

Prevention and treatment of postoperative pain with particular reference to children

Pain therapy is an important aspect of medical practice for patients of all ages, to optimize care, to obtain an adequate quality of life and to improve their general conditions. Pain is among the most prevalent symptoms experienced by patients undergoing surgery. The success of postoperative pain therapy depends on the ability of the clinician to assess the presenting problems, identify and evaluate pain syndromes and formulate a plan for comprehensive continuing care. The prevalence of acute pain has led to the need to develop techniques for the assessment and management of this symptom in order to focus the attention on an interdisciplinary therapeutic approach (including pharmacologic, cognitive-behavioral, psychologic and physical treatment) and on the timing of different interventions (pre and postoperative). In this chapter we describe the principal therapeutic approaches to control pain in post-operative patients, such as non-opioid, opioid and adjuvant analgesics with particular attention in paediatric age. Moreover we report the principal scales to assess the pain intensity in the post-operative period. The need of a multidisciplinatory team and of a pre and postoperative pain management program represents an important goal in order to obtain effective pain relief and optimize pediatric care and rapid recovery. The introduction of a perioperative team service will improve the approach to pain management programs and it is considered the most important challenge for future.