Hyperbaric prilocaine vs. hyperbaric bupivacaine for spinal anaesthesia in women undergoing elective caesarean section: a comparative randomised double-blind study.

Hyperbaric bupivacaine spinal anaesthesia remains the gold standard for elective caesarean section, but the resultant clinical effects can be unpredictable. Hyperbaric prilocaine induces shorter motor block but has not previously been studied in the obstetric spinal anaesthesia setting. We aimed to compare duration of motor block after spinal anaesthesia with prilocaine or bupivacaine during elective caesarean section. In this prospective randomised, double-blind study, women with uncomplicated pregnancy undergoing elective caesarean section were eligible for inclusion. Exclusion criteria included: patients aged < 18 years; height < 155 cm or > 175 cm; a desire to breastfeed; or a contra-indication to spinal anaesthesia. Patients were randomly allocated to two groups: the prilocaine group underwent spinal anaesthesia with 60 mg intrathecal prilocaine; and the bupivacaine group received 12.5 mg intrathecal heavy bupivacaine. Both 2.5 µg sufentanil and 100 µg morphine were added to the local anaesthetic agent in both groups. The primary outcome was duration of motor block, which was assessed every 15 min after arriving in the post-anaesthetic care unit. Maternal haemodynamics, APGAR scores, pain scores, patient satisfaction and side-effects were recorded. Fifty patients were included, with 25 randomly allocated to each group. Median (IQR [range]) motor block duration was significantly shorter in the prilocaine group, 158 (125-188 [95-249]) vs. 220 (189-250 [89-302]) min, p < 0.001. Median length of stay in the post-anaesthetic care unit was significantly shorter in the prilocaine group, 135 (120-180 [120-230]) vs. 180 (150-195 [120-240]) min, p = 0.009. There was no difference between groups for: maternal intra-operative hypotension; APGAR score; umbilical cord blood pH; maternal postoperative pain; and patients' or obstetricians' satisfaction. We conclude that hyperbaric prilocaine induces a shorter and more reliable motor block than hyperbaric bupivacaine for women with uncomplicated pregnancy undergoing elective caesarean section.

Spinal anaesthesia in neonates and infants: what about the cerebral oxygen saturation?

BACKGROUND: Spinal Anaesthesia (SA) has been firmly established as an efficient and safe technique, with minimal cardio-respiratory disturbance when administered in the neonatal period. Our objective was to assess the haemodynamic consequences of SA in infants, particularly its impact on cerebral perfusion using near-infrared spectroscopy (NIRS)-based cerebral oximetry (rSco2). METHODS: All infants up to 60 weeks' postmenstrual age, whether formerly preterm or not, and undergoing spinal anaesthesia, were enrolled. Haemodynamic data records, rSco2 and mean arterial blood pressure (MAP), were prospectively collected before SA (T0) and every five min for 30 min (T30) after the puncture. Compared with baseline measures, any changes of > 10% in rSco2 and of > 20% in MAP were considered clinically significant. Relative variations of data between T0 and T30 were analysed. RESULTS: Data of 103 infants were analysed. The mean relative changes in rSco2 were -2.25% (97.5% CI [-3.97; -0.5]) at T15, and 0.11% (97.5% CI [-1.67; 1.90]) at T30. No significant variation of rSco2 was recorded. The mean changes in MAP were respectively -13.94% (97.5% CI [-17.74; -10.14]) at T15 and -20.27% (97.5% CI [-24,25; -16.29]) at T30. MAP decrease was statistically and clinically significant 30 min after SA. No correlation between changes in MAP and rSco2 was found. The subgroup analysis did not reveal any effect of added intrathecal clonidine or preterm birth history on these results. CONCLUSIONS: In neonate and infants, SA did not cause clinically significant variation in cerebral oxygen saturation. Despite a significant decrease in MAP, cerebral auto-regulation seems to remain effective in neonates and not altered by spinal anaesthesia.

Enhanced visual acuity with echogenic needles in ultrasound-guided axillary brachial plexus block: a randomized, comparative, observer-blinded study.

BACKGROUND: We prospectively evaluated the effect of insertion angle on the visibility of echogenic and nonechogenic needles in phantoms and in axillary nerve blocks in patients. METHODS: Conventional and echogenic needles were studied in phantoms at insertion angles of 0-30°, 30-45°, and ≥ 45°. Operators rated comfort and image quality during the procedure and experts blinded to the needle groups randomly analyzed videos for tip and shaft visibility, surrounding tissue visibility, sharpness of the needle surface, and percentage of time with the needle completely visible. Patients scheduled for axillary nerve block were prospectively enrolled in the clinical study. Needle insertion angles were 0-30° for the median nerve approach, 30-45° for the radial nerve, and ≥ 45° for the musculocutaneous nerve. The same needle parameters were analyzed during the procedure and on videos. RESULTS: Physician comfort and image quality were significantly better for echogenic needles for phantoms and patients at 30-45° and ≥ 45° insertion angles. Needle tip and shaft visibility at 30-45° and ≥ 45° insertion angles in phantoms and for the musculocutaneous nerve in patients were significantly improved, as well as the percentage with complete needle visualization during the procedure. Tissue visibility and needle sharpness were significantly superior for conventional needles. There were no differences concerning block parameters and adverse events. CONCLUSION: Needles with enhanced echogenicity improved physician comfort, image quality, needle visibility, and visualization time of the needle during ultrasound-guided procedures in phantoms and axillary nerve blocks using insertion angles of 30-45° and ≥ 45°.

[Epidemiologic picture of one-year-pediatric anesthesia in France]. / Photographie épidémiologique d'une année d'anesthésie pédiatrique en France.

INTRODUCTION: Nowadays, the epidemiological data on French pediatric anesthesia is limited. The purpose of this study was to perform an "epidemiological picture" of this activity. MATERIAL AND METHOD: From the national Program Information System Medicalization, we have identified the institutions of France performing more than 50 anesthesia by year in children under 15 years in 2008 and noted the demographic data, types of institutions, hospital stay and surgeries. RESULTS: Seven hundred and eighty-nine thousands and two hundred anesthetic procedures have performed during 648,018 hospital stays in 929 institutions. A percentage of 68.4% of children were between 3 and 15 years old, 26.7% between 1 and 3 years, 4.1% between 1 year and 1 month and 0.8% less than one month, including 62% of boys and 38% of girls. A percentage of 53.6% of hospital stays were realized in private institutions, 20.9% in University Hospitals (UH), and 20.4% in General hospitals (GH), mainly in day-case surgery (60%), 15.2% in stay of 24h and 24.8% in full hospital stay (FHS). The main surgeries were ENT (29%), digestive (21%), orthopedic (14%), urology (12%) and plastics (9%). Children less than 1 year old were managed by University Hospital and during FHS. Older children were managed in private institution and during day-case surgery. CONCLUSION: Over 50% of stays with anesthesia were performed in private institution and during day-case surgery. Controversially, the management of children younger than 1 year was mainly in University Hospital.

Intraoperative use of transoesophageal Doppler to predict response to volume expansion in infants and neonates.

BACKGROUND: Volume expansion (VE) in neonates or infants during volatile anaesthesia may lead to fluid overload if inappropriate. Transoesophageal Doppler (TED), a non-invasive cardiac output monitoring technique, can provide a comprehensive estimation of the volaemic status. We evaluated whether intraoperative TED-derived parameters can predict volume responsiveness. METHODS: Neonates and infants under general anaesthesia without myocardial dysfunction were prospectively included when the attending anaesthetist, blinded to TED measurements, decided to provide VE based on clinical appreciation and standard monitoring data. Standard and TED-derived data were recorded before and after VE. After VE, patients were classified as responders and non-responders, if their indexed stroke volume (iSV) increased by more than 15% or not, respectively. The attending anaesthetist assessment of VE responsiveness was recorded at the end of VE. RESULTS: Fifty patients aged 42 (4) post-conceptional weeks were included, among which 26 (52%) were responders. Baseline iSV was the only parameter associated with VE responsiveness. Baseline iSV was fairly correlated with VE-induced changes in iSV (ρ=-0.64) and was associated with an area under the receiver operating characteristic curve of 0.90 (0.80, 0.99). Using a cut-off of 25 ml m(-2), baseline iSV predicted volume responsiveness with a sensitivity of 92% and a specificity of 83%. Attending anaesthetists' assessment of VE effectiveness agreed only moderately with TED measurements of iSV changes. CONCLUSIONS: TED-derived iSV measurement during volatile anaesthesia is useful to predict and follow VE responsiveness in neonates and infants without myocardial dysfunction.

Phase-controlling phononic crystals: realization of acoustic Boolean logic gates.

A phononic crystal (PC) consisting of a square array of cylindrical polyvinylchloride inclusions in air is used to construct a variety of acoustic logic gates. In a certain range of operating frequencies, the PC band structure shows square-like equi-frequency contours centered off the gamma point. This attribute allows for the realization of non-collinear wave and group velocity vectors in the PC wave vector space. This feature can be utilized to control with great precision, the relative phase between propagating acoustic waves in the PC. By altering the incidence angle of the impinging acoustic beams or varying the PC thickness, interferences occur between acoustic wave pairs. It is recognized that information can be encoded with this mechanism (e.g., wave amplitudes/interference patterns) and accordingly to construct a series of logic gates emulating Boolean functions. The NAND, XOR, and NOT gates are demonstrated with finite-difference time-domain simulations of acoustic waves impinging upon the PC.

[Comparison of saline, air, and a mixture oxygen-nitrous oxide for endotracheal cuff tracheal tube inflation in children? A prospective randomized trial]. / Comparaison de sérum salé, d'air et d'un mélange oxygène-protoxyde d'azote pour le remplissage des ballonnets de sondes d'intubation chez l'enfant? Étude prospective randomisée.

OBJECTIVE: The purpose of the present study was to compare how many inflate and deflate are necessary to maintain the endotracheal tube cuff pressure between 15 and 35 cm H2O by using air, O2-N2O mix or saline solution. STUDY DESIGN: Randomized and prospective study. PATIENTS AND METHODS: Ninety children from 1 month to 15 years of age were included in the study. All patients were ventilated with O250%-N2O50%. Subsequently, the patients were divided in three groups: (1) Group 1: patients with air inflated cuffs; (2) Group 2: patients with O2-N2O mix inflated cuffs; (3) Group 3: patients with saline solution inflated cuffs. In all groups cuffs were inflated to reach an intracuff pressure of 20 cm H2O. The cuff pressure was then monitored every 10 minutes and adjusted to be between 15 and 35 cm H2O. Laryngeal and tracheal symptoms were noted in the recovery room. RESULTS: The three groups of patients were similar for age, weight, and sex. The length of surgery was significantly longer in Group 3. The deflate rate was higher in Group 1 (60%) than in Group 2 (10%) or 3 (3.3%) (p<0.0001). The inflate rate was higher in Group 2 (76.6%) than in Group 1 or 3 (both 3.3%) (p<0.0001). Side effects were comparable in the three groups of patients. CONCLUSION: Using air or O2-N2O mix to inflate cuffs is not reliable. SSI helps to maintain a more stable cuff pressure but monitoring is difficult and sometimes contraindicated by tracheal tubes producers. Inflating cuffs with air and regularly monitoring pressure is the most reliable and easiest technique.

[Continuous epidural block versus continuous psoas compartment block for postoperative analgesia after major hip or femoral surgery in children: a prospective comparative randomized study]. / Analgésie péridurale continue versus bloc continu du compartiment psoas pour l'analgésie postopératoire après chirurgie majeure du bassin ou du fémur chez l'enfant : étude prospective comparative randomisée.

BACKGROUND: Intravenous opioids and/or continuous epidural block (CEB) are used for postoperative analgesia after hip and/or femoral shaft surgery but adverse effects limit their use in children. A continuous psoas compartment block (CPCB), effective technique in adults can be an alternative. In this randomized comparative study, we wanted to evaluate CEB and CPCB in children after major hip surgery in terms of adverse events, pain relief and ropivacaine plasma concentrations. METHODS: After ethical committee and parents' approval, 40 children scheduled for hip surgery were included and randomly allocated to receive CPCB or CEB. After general anaesthesia induction, 0.5 mL/kg of 0.375% ropivacaine were injected via the epidural or lumbar plexus catheter. After surgery, 0.1 ml/kg per hour (group CPCB) or 0.2 ml/kg per hour (group CEB) of 0.2% ropivacaine was infused for 48h. Post-operative pain was evaluated using VAS or CHIPPS scores values at h1, h6, h12, h18, h24, h36 and h48, as well as doses of first line (paracetamol 15 mg/kg/6h) or second line rescue analgesia (0.2mg/kg intravenous nalbuphine), if pain score remained high after 30 mm. niflumic acid was systematically used. Adverse events were noted as well as parents' satisfaction at 48h. Ropivacaine plasma concentrations were measured four times up to 48h (h1, h6, h24 and h48) by high performance gas chromatography. RESULTS: Forty children 1 to 12 years old (CPCB=20, CEB=20) were included. The demographic data were equivalent in both groups. Postoperative analgesia was excellent for both continuous block techniques during the whole studied period. Doses of rescue analgesics were comparable in both groups at the end of the 48h. Number of children who had at least one side effect is significantly higher in CEB group. Furthermore, the number of local anaesthetic premature stops was significantly more frequent in this group. Median values of ropivacaine plasma level in CEB group were significantly higher than CPCB group at h6 and h24. Ten parents in the CEB group and 15 in CPCB group were satisfied. CONCLUSION: Continuous psoas compartment block is an effective technique of postoperative analgesia after major hip or femoral surgery in children. It equally manages postoperative pain with significantly less adverse event and decreased ropivacaine doses and plasma concentration than CEB.

Avoiding propofol injection pain in children: a prospective, randomized, double-blinded, placebo-controlled study.

BACKGROUND: Pain on injection limits the use of propofol in children. The combination of lidocaine and propofol is widely used to reduce pain. A new solvent [medium-chain triglyceride (mct)/long-chain triglyceride (lct)] has been advocated to be less painful than standard (lct) propofol in adults, but no information is available of its usefulness in pre-school children. We designed a prospective, randomized, double-blinded, placebo-controlled study to assess injection pain with two different propofol emulsions, each given with or without lidocaine in children <7 yr. METHODS: A total of 160 ASA I-III children were randomly assigned to receive lct-propofol or mct/lct-propofol, 5 mg kg(-1), with lidocaine 10 mg ml(-1) or saline. The site and size of venous cannulation and restlessness before injection were recorded in each patient. A pain score graded 0-6 was established based on spontaneous verbal and motor reaction during injection, each graded 0-3. Kruskall-Wallis and Mann-Whitney tests were used for statistical analysis. RESULTS: Median pain scores decreased in all groups compared with lct-propofol-saline (P<0.001) and were least in the lct/mct-propofol-lidocaine group (P<0.001). Painless injection (score, 0-2) occurred in 92.5% of patients in the mct/lct-propofol-lidocaine group compared with 41-77% in the others (P<0.001). CONCLUSIONS: Mct/lct-propofol caused significantly less pain than lct-propofol in preschool children. Mixing of lidocaine with mct/lct-propofol resulted in a further significant decrease, virtually eliminating the pain on injection.