Evaluation of the analgesia nociception index for monitoring intraoperative analgesia in children.

BACKGROUND: Intraoperative analgesia is still administered without guidance. Anaesthetists decide upon dosing on the basis of mean population opioid pharmacological studies and in response to variations in haemodynamic status. However, those techniques have been shown to be imprecise. We assessed the diagnostic value of monitoring the analgesia nociception index (ANI) to detect surgical stimulation in children. METHODS: This was an observational study of 2- to 12-yr-old patients 5 min before and after surgical incision. Hypnosis was maintained with sevoflurane and guided by bispectral index. Intraoperative analgesia was administered as a remifentanil infusion titrated to variations in haemodynamic parameters, and ANI monitor values were recorded. ANI parameters assessed included instantaneous ANI (ANIi), mean ANI (ANIm), and the relative change of ANIi to ANIm (DeltaANI=ANIi-ANIm/ANIm). Statistical analyses were performed using receiver-operating-characteristic analysis with determination of the area under the receiver operating characteristic (AUROC) curve and the grey zone. RESULTS: Overall, 49 subjects were included in this study. The AUROC was 0.755 (0.738-0.772), 0.771 (0.755-0.787), and 0.756 (0.738-0.774) for ANIi, ANIm, and DeltaANI, respectively. The threshold of ANI parameters indicating the presence of noxious surgical stimuli was ≤53%, ≤56%, and ≤-13.3% for ANIi, ANIm, and DeltaANI, respectively. The percentage of subjects in the inconclusive zone was 41%, 51%, and 33% for ANIi, ANIm, and DeltaANI, respectively. CONCLUSIONS: ANI has diagnostic value for detecting surgical stimuli in children.

Ketamine for chronic non-cancer pain: A meta-analysis and trial sequential analysis of randomized controlled trials.

BACKGROUND: Ketamine has been suggested to be efficient in relieving chronic pain. However, there is inconsistency across studies investigating the effect of ketamine for chronic pain management. We aimed to perform a meta-analysis in order to assess the efficacy of this compound during chronic non-cancer pain conditions. METHODS: The study consisted in a meta-analysis of clinical trials comparing ketamine to a placebo during chronic non-cancer pain. The primary endpoint of this study was pain relief 4 weeks after the beginning of treatment. Secondary outcomes were: pain relief 1, 2, 8 and 12 weeks after the beginning of treatment and incidence of psychedelic manifestations. RESULTS: Six studies were included in this meta-analysis. Overall, 99 patients received ketamine and 96 received placebo. Ketamine did not decrease pain intensity at 4 weeks (MD (on a 0 to 10 scale) = -1.12 [-2.33, 0.09], GRADE evidence: very low). However, analysing studies with no high-risk bias found ketamine to decrease pain intensity at 4 weeks and increased the level of GRADE evidence to moderate. Trial sequential analysis confirmed the overall result and revealed the lack of power of this meta-analysis. Ketamine also decreased pain intensity at all other evaluated points in time. Ketamine increased the incidence of psychedelic manifestations in comparison to placebo. CONCLUSION: Results of this meta-analysis found moderate evidence suggesting the efficacy of ketamine during chronic pain. Further studies are warranted to conclude about the effect of ketamine during chronic pain conditions and to determine optimal administration regimes of this agent during this condition. SIGNIFICANCE: Ketamine has been found interesting for managing chronic pain. We performed a meta-analysis aiming to confirm those results. Ketamine was found efficient in alleviating pain up to 12 weeks after the beginning of treatment. However, overall evidence favouring the use of this compound was very low.

Validation of a simple tool for anxiety trait screening in children presenting for surgery.

BACKGROUND.: Screening for preoperative anxiety is an important challenge during the preoperative period. The aim of our study was to validate the faces scale used to detect anxiety trait in children. METHODS.: Children aged 8-18 yr were asked to quantify their anxiety trait using the readily available faces scale and to respond to the trait component of the State-Trait Anxiety Inventory (STAI) for children (C) or adults (A) before the anaesthesia consultation. Using receiver operating characteristics analysis, we determined the faces scale optimal value on a construct cohort. A validation cohort was recruited to assess the accuracy of the results. RESULTS.: The construction cohort comprised 207 patients and the validation cohort 91 patients. The receiver operating characteristics analysis found an area under the curve of 0.75 [95% confidence interval (CI) 0.67, 0.83]. The optimal value for faces scale score was 4, with a sensitivity of 0.61 [95% CI 0.59, 0.62] and a specificity of 0.82 [95% CI 0.81, 0.83]. When this threshold was applied to the construction and validation cohorts, 61.3 and 44.4% of positives were true positives in the construction and validation cohorts, respectively; and 82.1 and 81.3% of negatives were true negatives, respectively. CONCLUSIONS.: Our study determined the performance of a simple faces scale to measure the preoperative anxiety trait in children aged 8-18 yr. This tool is potentially helpful for clinicians aiming to identify patients at risk of preoperative anxiety and to assign them to targeted management.

Efficacy of intraoperative dexmedetomidine compared with placebo for surgery in adults: a meta-analysis of published studies.

Dexmedetomidine (Dex) demonstrates sedative and analgesic effects. We investigated the intraoperative and postoperative effects of intraoperative Dex administration during surgery in adult patients. A search for randomized placebo-controlled trials was conducted in Pubmed and Embase databases to identify randomized controlled clinical trials using intraoperative Dex for surgery in adult population. Outcome assessed were: intraoperative and postoperative opioid consumption, time of recovery from anesthesia, postoperative pain, and postoperative nausea or vomiting (PONV) in the first 24 hours. Data from each trial were combined to calculate pooled odds ratios (OR), mean difference (MD) or standardized mean difference (SMD) and 95% confidence interval (95 % CI). Heterogeneity was measured using I² statistics. Eighteen randomized controlled trials were analyzed. Dex was administered to 815 patients and 410 received placebo. Overall, Dex significantly decreased intraoperative opioid consumption (SMD=-1.58 [-2.98, -0.19], I²=95 %, P<0.00001), but did not decrease time of recovery from anesthesia (SMD=-0.13 [-1.60, 1.34] minutes, I²=95 %, P<0.00001). Dex significantly reduced postoperative opioid consumption (SMD=-1.58 [-2.98, -0.19], I²=95 %, P<0.00001), postoperative pain intensity (SMD=-0.73 [-1.19, -0.27], I²=62 %, P=0.03), and the prevalence of PONV (OR=0.43 [0.27, 0.69], I²=0 %, P=0.46). This meta-analysis shows that intraoperative Dex administration in adult patients reduces intra and postoperative opioid consumption, postoperative pain and PONV. Time of recovery is not affected.

[Sub-capsular renal hematoma during severe preeclampsia: clinical case and review of the literature]. / Hématome sous-capsulaire du rein compliquant une prééclampsie sévère: cas clinique et revue de la littérature.

Renal haematoma during severe preeclampsia is a rare uneventful event. It is usually associated with other organ injury such as cerebral or liver haematoma. Imaging (ultrasound or tomodensitometry examination) plays an important role in detecting this complication and following its evolution. In the current case report, we describe an isolated renal haematoma during a severe preeclampsia complicated by a HELLP syndrome. This patient was managed with a conservative treatment (control of arterial pressure and induction of delivery) and an imaging follow-up.

Limits of agreement between measures obtained from standard laboratory and the point-of-care device Hemochron Signature Elite(R) during acute haemorrhage.

BACKGROUND: Rapid diagnosis of coagulopathy in the bleeding patient using point-of-care (POC) devices would be ideal. The Hemochron Signature Elite(®) (HC(®)) is a POC device that determines international normalized ratio (INR) and activated partial thromboplastin time (aPTT). The aim of the study was to evaluate the agreement for INR and aPTT between the HC(®) and standard laboratory values in acute haemorrhage. METHODS: This was a single-centre observational prospective study including patients with acute haemorrhage. Laboratory INR and aPTT were compared with simultaneous measurements performed with the HC(®). The diagnostic performance of HC(®) was determined; bias and limits of agreement were calculated according to the method of Bland and Altman. RESULTS: Seventy-two pairs of measurements from 39 patients were analysed. The bias between the INR-HC(®) and aPTT-HC(®) measurements and the central laboratory were 0.02 and -1.13, respectively. The Spearman's correlation coefficients for the INR-HC(®)/INR-lab and the aPTT-HC(®)/aPTT-lab were 0.68 and -0.29, respectively. Twenty-seven per cent of INR-HC(®) values and 89% of the aPTT-HC(®) values exceeded the predefined limits of agreement. The INR-HC(®) measurement identified patients with a central laboratory INR >1.5 with a sensitivity, specificity, and positive and negative predictive values of 83%, 70%, 76%, and 77%, respectively. CONCLUSIONS: The results showed a lack of agreement between the INR-HC(®) and the aPTT-HC(®) measurements and the standard laboratory in the context of acute haemorrhage. The INR-HC(®) showed moderate performance as a decision-making tool to detect coagulopathy in the context of acute haemorrhage.

Postoperative decrease in plasma sodium concentration after infusion of hypotonic intravenous solutions in neonatal surgery.

BACKGROUND: Hypotonic i.v. solutions can cause hyponatraemia in the context of paediatric surgery. However, this has not been demonstrated in neonatal surgery. The goal of this study was to define the relationship between infused perioperative free water and plasma sodium in neonates. METHODS: Newborns up to 7 days old undergoing abdominal or thoracic surgery were included in this prospective, observational study. Collected data included type and duration of surgery, calculated i.v. free water intake, and pre- and postoperative plasma sodium. Statistical analyses were performed using the Pearson correlation, Mann-Whitney test, and receiver operating characteristic analysis with a 1000 time bootstrap procedure. RESULTS: Thirty-four subjects were included. Postoperative hyponatraemia occurred in four subjects (11.9%). The difference between preoperative and postoperative plasma sodium measurements (ΔNaP) correlated with calculated free water intake during surgery (r=0.37, P=0.03), but not with preoperative free water intake. Calculated operative free water intake exceeding 6.5 ml kg(-1) h(-1) was associated with ΔNaP≥4 mM with a sensitivity and specificity [median (95% confidence interval)] of 0.7 (0.9-1) and 0.5 (0.3-0.7), respectively. CONCLUSIONS: Hypotonic solutions and i.v. free water intake of more than 6.5 ml kg(-1) h(-1) are associated with reductions in postoperative plasma sodium measurements ≥4 mM. In the context of neonatal surgery, close monitoring of plasma sodium is mandatory. Routine use of hypotonic i.v. solutions during neonatal surgery should be questioned as they are likely to reduce plasma sodium.

[Hyperbaric oxygen therapy and inert gases in cerebral ischemia and traumatic brain injury]. / Oxygénothérapie hyperbare et gaz inertes dans l'ischémie cérébrale et le traumatisme crânien.

Cerebral ischemia is a common thread of acute cerebral lesions, whether vascular or traumatic origin. Hyperbaric oxygen (HBO) improves tissue oxygenation and may prevent impairment of reversible lesions. In experimental models of cerebral ischemia or traumatic brain injury, HBO has neuroprotective effects which are related to various mechanisms such as modulation of oxidative stress, neuro-inflammation or cerebral and mitochondrial metabolism. However, results of clinical trials failed to prove any neuroprotective effects for cerebral ischemia and remained to be confirmed for traumatic brain injury despite preliminary encouraging results. The addition of inert gases to HBO sessions, especially argon or xenon which show neuroprotective experimental effects, may provide an additional improvement of cerebral lesions. Further multicentric studies with a strict methodology and a better targeted definition are required before drawing definitive conclusions about the efficiency of combined therapy with HBO and inert gases in acute cerebral lesions.

[Opioid-sparing effect of ketamine during tonsillectomy in children]. / Effet d'épargne morphinique de la kétamine au cours de l'amygdalectomie chez l'enfant.

INTRODUCTION: In the adult population, Ketamine is currently used as an antihyperalgesic and opioid-sparing agent during the perioperative period. However, for doses of ketamine up to 0.5mg/kg, these effects have not been found in pediatric population. The aim of the present study was to evaluate the efficacy of a preoperative bolus of 1mg/kg of ketamine on postoperative pain intensity and morphine consumption in children undergoing tonsillectomy. METHODS: We have undertaken a retrospective comparison of 60 consecutive children operated for tonsillectomy in our institution before (first 30 patients) and after (last 30 patients) the introduction of a preoperative bolus of 1mg/kg of ketamine. Data collected were: age, ASA score, dose of intraoperative sufentanil, OPS score during PACU stay and the first postoperative day, morphine consumption during PACU stay and the first postoperative day, psychodysleptic manifestations, pain at first solid oral intake and postoperative respiratory complications or haemorrhage. RESULTS: No difference was found between the two groups in terms of demographic characteristics. Perioperative doses of sufentanil, postoperative opioid consumption or pain score in PACU or during 24hours were similar between the two groups. The two groups did not differ in terms of pain at first oral intake, or other adverse effects. CONCLUSION: These results suggest that 1mg/kg of ketamine administered right after anaesthesia induction in children undergoing tonsillectomy did not result in an opioid sparing effect.

[Anesthetic malignant hyperthermia: what's new in 2012?]. / Quoi de neuf en hyperthermie maligne en 2012 ?

Malignant hyperthermia (MH) is a pharmacogenetic disorder of anesthesia. Recent advances dealing with epidemiology of MH and the safe anesthetic course of MH susceptible patients are shortly presented here with a special insight into the preparation of modern anesthesia workstations, which they will share in operating room.

An individual scoring system for the prediction of postpartum anaemia.

BACKGROUND: Postpartum anaemia (PPA) is a common postpartum complication. The goal of this study was to prospectively construct a predictive score for individual risk of PPA. PATIENTS ET METHOD: We prospectively analyzed factors associated with PPA (<10gdL(-1) at 48hours postpartum). Parameters analyzed were demographic data, pregnancy characteristics, delivery and postpartum characteristics. Univariate analysis was performed using Anova or X(2); the Cox model was used for multivariate analysis. The scoring system was validated using ROC curve. RESULTS: Analysis was performed in 475 patients and validation was carried using an additional 95 patients. Multivariate analysis found four factors independently associated with PPA: anaemia during the third trimester of the pregnancy, Southeast Asian ethnic origin, episiotomy and severe postpartum haemorrhage (PPH) identified by the use of sulprostone. According to the score derived from the Cox model, patients were classified as low (22%, score=0), medium (55%, score=2 or 3) and high (86%, score>3) probability of PPA. Using the AUC of the ROC curve for both the first and the validation cohorts (performed on 95 further patients), we recorded AUCs of 72% and 70% respectively. CONCLUSIONS: This study allowed the derivation and validation of a predictive score of PPA. This score might be useful in targeting prophylactic strategies for PPA. Such strategies could include a more active treatment of iron deficiency (increasing oral iron treatment observance or intravenous iron therapy) especially in exposed population, improvement in the prevention and treatment of postpartum haemorrhage and decreasing the use of episiotomy. Future studies must focus on the external validation and generalisation of this scoring system.

[Neurological consequences after long-term sedation in the ICU]. / Conséquences neurologiques de la sédation en réanimation.

Experiments performed in mammals, including non-human primates, have demonstrated an increase in neuronal death rates normally seen in normal brain development. Such an increase is encountered in diseases but also after exposure of the brain to various class of anaesthetics. In living animals, it can (but not always) result in persistent cognitive impairment. Most of the experiments have been conducted in animals which were never exposed to any pain, which questions their relevancy. On the clinical side, all data comes from retrospective studies. Given the multiple bias, they cannot definitely state that a protocol, if toxic, is more or less when compared to another. Until now, prospective follow-up of children exposed to anaesthetics in utero or during the first months of life do not suggest a major deleterious effect. Yet, a minor one, if existing, would be hard to detect among polluting variables (e.g. pathology requiring anaesthesia, long hospitalization after birth, preterm birth, environmental stress...). For sure, when surgery is mandatory during pregnancy, it is generally for maternal indication and should not be a motif strong enough for foetal extraction, especially in terms where the baby has few chances to survive. Second, it is known for years than anaesthesia before 1 year of age is much riskier than after 1 year, whatever the theorical neurotoxicity is. Third, this enforces the need to develop tools enhancing the precision of anaesthesia as much as possible. Meanwhile, when an infant has undergone numerous general anaesthesias, we strongly recommend a long-time neurological follow-up.

An observational study of factors leading to difficulty in resident anaesthesiologists identifying the epidural space in obstetric patients.

BACKGROUND: Multiple attempts at needle placement for neuraxial block may cause patient discomfort, a higher incidence of spinal haematomas, postdural puncture headache and nerve trauma. The aim of this study was to evaluate the factors predicting difficult epidural analgesia for inexperienced residents. METHODS: In this prospective observational study, conducted in a teaching hospital, four anaesthesiology residents without prior experience in obstetric anaesthesia performed all epidural procedures. A difficult epidural was defined as a need for more than one attempt at catheter placement. The following patient data were recorded: body mass index, abdominal circumference (classified as <105 or ≥ 105 cm), ability to palpate anatomical landmarks and spinal abnormality. RESULTS: Four hundred and twelve pregnant women in labour were recruited. Residents achieved successful cannulation of the epidural space in 74% of attempts. Factors associated with difficult epidural placement in the univariate analysis were body mass index > 30 kg/m(2), an abdominal circumference > 105 cm, inability to palpate spinous processes and spinal abnormality. With the exception of abdominal circumference, all factors were independently predictive of difficult placement in the multivariate analysis with spinal abnormality being the most significant factor. CONCLUSIONS: For residents with no prior experience in obstetric anaesthesia, the most reliable factor in predicting difficult epidural cannulation was spinal abnormality.

Pharmacological prevention of sevoflurane- and desflurane-related emergence agitation in children: a meta-analysis of published studies.

BACKGROUND: Emergence agitation (EA) in children is increased after sevoflurane anaesthesia. The efficacy of prophylactic treatment is controversial. The aim of this study was to provide a meta-analysis of the studies of the pharmacological prevention of EA in children. METHODS: A comprehensive literature search was conducted to identify clinical trials that focused on the prevention of EA in children anaesthetized with sevoflurane, desflurane, or both. The data from each trial were combined using the Mantel-Haenszel model to calculate the pooled odds ratio (OR) and 95% confidence interval. I(2) statistics were used to assess statistics heterogeneity and the funnel plot and the Begg-Mazumdar test to assess bias. RESULTS: Thirty-seven articles were found which included a total of 1695 patients in the intervention groups and 1477 in the control ones. Midazolam and 5HT(3) inhibitors were not found to have a protective effect against EA [OR=0.88 (0.44, 1.76); OR=0.39 (0.12, 1.31), respectively], whereas propofol [OR=0.21 (0.16, 0.28)], ketamine [OR=0.28 (0.13, 0.60)], alpha(2)-adrenoceptors [OR=0.23 (0.17, 0.33)], fentanyl [OR=0.31 (0.18, 0.56)], and peroperative analgesia [OR=0.15 (0.07, 0.34)] were all found to have a preventive effect. Subgroup analysis according to the peroperative analgesia given does not affect the results. CONCLUSIONS: This meta-analysis found that propofol, ketamine, fentanyl, and preoperative analgesia had a prophylactic effect in preventing EA. The analgesic properties of these drugs do not seem to have a role in this effect.

Premedication with clonidine is superior to benzodiazepines. A meta analysis of published studies.

BACKGROUND: Premedication is considered important in pediatric anesthesia. Benzodiazepines are the most commonly used premedication agents. Clonidine, an alpha2 adrenoceptor agonist, is gaining popularity among anesthesiologists. The goal of the present study was to perform a meta-analysis of studies comparing premedication with clonidine to Benzodiazepines. METHODS: A comprehensive literature search was conducted to identify clinical trials focusing on the comparison of clonidine and Benzodiazepines for premedication in children. Six reviewers independently assessed each study to meet the inclusion criteria and extracted data. Original data from each trial were combined to calculate the pooled odds ratio (OR) or the mean differences (MD), 95% confidence intervals [95% CI] and statistical heterogeneity were accessed. RESULTS: Ten publications fulfilling the inclusion criteria were found. Premedication with clonidine, in comparison with midazolam, exhibited a superior effect on sedation at induction (OR=0.49 [0.27, 0.89]), decreased the incidence of emergence agitation (OR=0.25 [0.11, 0.58]) and produced a more effective early post-operative analgesia (OR=0.33 [0.21, 0.58]). Compared with diazepam, clonidine was superior in preventing post-operative nausea and vomiting (PONV). DISCUSSION: Premedication with clonidine is superior to midazolam in producing sedation, decreasing post-operative pain and emergence agitation. However, the superiority of clonidine for PONV prevention remains unclear while other factors such as nausea prevention might interfere with this result.