The effect of continuous wound infusion of ropivacaine on postoperative pain after median sternotomy and mediastinal drain in children.

BACKGROUND: Postoperative pain after median sternotomy is usually treated with i.v. opioids. We hypothesized that continuous wound infusion of ropivacaine decreases postoperative morphine consumption and improves analgesia in children who undergo cardiac surgery. METHODS: This randomized, double-blind study comprised 49 children aged 1-9 years who underwent atrial septal defect (ASD) closure. Patients received continuous local anesthetic wound infiltration either with 0.2% ropivacaine, 0.3-0.4 mg·kg(-1) ·h(-1) (Group R) or with saline (Group C). Rescue morphine consumption, Objective Pain Scale (OPS), time to mobilization, time to enteral food intake, and time to discharge were recorded. RESULTS: There were no statistically significant differences in morphine consumption at 24, 48, and 72 h postsurgery between R and C groups. There was a weak evidence for a difference in the time to the first morphine administration after tracheal extubation to be longer for Group R than Group C (186.2 vs 81.0 min; 95% CI (-236.5, 26.2), P = 0.114). The incidence of nausea and vomiting were comparable between the groups. No signs or symptoms of local anesthetic toxicity were registered. CONCLUSIONS: Contrary to our hypothesis, continuous ropivacaine wound infusion did not reduce morphine consumption, pain score values, or nausea and vomiting in children who underwent ASD closure with median sternotomy and mediastinal drain.

Spectral entropy as a measure of hypnosis and hypnotic drug effect of total intravenous anesthesia in children during slow induction and maintenance.

BACKGROUND: We evaluated whether spectral entropy (SpE) can measure the depth of hypnosis and the hypnotic drug effect in children during total intravenous anesthesia. METHODS: Sixty healthy children, aged 3-16 yr, were studied. Anesthesia was induced with an increasing target controlled infusion of propofol, and maintained by a stable remifentanil infusion and variable concentrations of target controlled infusion propofol. Depth of hypnosis was assessed according to the University of Michigan Sedation Scale (UMSS). Estimated plasma (C(p)) and pseudo effect site (C(eff)) propofol concentrations reflected the hypnotic drug effect. Patients were stratified to three age groups. The correlations between SpE versus UMSS, C(p), and C(eff) were analyzed by Prediction Probability (P(k)). The pharmacodynamic relationship between SpE and C(p), and the differences of SpE values between the age groups at the corresponding UMSS levels, were studied. RESULTS: Respective mean P(k) values for the youngest, middle, and oldest age groups were: 1) during induction: SpE versus UMSS 0.87, 0.87, and 0.93; SpE versus C(p) 0.92, 0.95, and 0.97; and SpE versus C(eff) 0.88, 0.94, and 0.95; 2) during maintenance: SpE versus C(eff) 0.86, 0.75, and 0.81. The pharmacodynamic analysis determined an association between SpE and C(p) that followed the E(max) model closely. There were significant differences in SpE values between age groups at corresponding UMSS sedation levels. CONCLUSIONS: SpE measures the level of hypnosis and hypnotic drug effect in children during total intravenous anesthesia. There is an age dependency associated with SpE. Anesthesia should not be steered solely on the basis of SpE.

The Narcotrend index indicates age-related changes during propofol induction in children.

BACKGROUND: The Narcotrend electroencephalogram monitor is designed to measure hypnotic state during anesthesia. We performed this study to evaluate the effectiveness and reliability of the Narcotrend monitor in assessing hypnotic state and loss of consciousness (LOC) during propofol anesthesia induction in children. METHODS: Sixty-two children, aged 1-5 (n = 17), 6-12 (n = 23), and 13-16 (n = 21) yr, scheduled for elective surgery were studied. The patients were premedicated with oral midazolam 0.5 mg/kg. After IV access, propofol target controlled infusion (TCI) was started with 0.5 microg/mL and increased by 0.5 microg/mL increments every 2 min until the child did not respond to any verbal command or physical stimuli. A manual scheme was used for children weighing <15 kg. Hypnotic state was measured every minute from the start of the propofol infusion using the University of Michigan Sedation Scale (UMSS). LOC was defined as a transition of UMSS scale value 2 to 3. The Narcotrend index (NI) was recorded before the start of induction and during the whole study period. NI values were noted simultaneously, yet independently of the sedation measurements. Prediction probability (PK) was used to assess the correspondence between NI and UMSS. Sensitivity and specificity of NI for differentiating between consciousness and unconsciousness were calculated. NI values at specific UMSS levels were compared between the different age groups and the relationships between TCI propofol concentrations and sedation levels were assessed using correlation analysis. RESULTS: A PK-value of 0.84 (95% CI [0.80-0.88]) of NI was calculated from the data for the detection of LOC. Similarly, a PK value of 0.82 (95% CI [0.78-0.86]) indicated agreement between NI and UMSS values. The average NI values differed between successive UMSS sedation levels 0 and 1 and levels 1 and 2 (P < 0.01). In the youngest age group, the NI discriminated between UMSS levels 2 and 3, in the second age group between levels 1 and 2 and 2 and 3, and in the oldest age group between 0 and 1. Furthermore, the NI values differed significantly between age groups at UMSS levels 1-4 (P < 0.005), with the NI values being higher in younger compared with older children. The average NI value at LOC was 68. For the detection of consciousness, a sensitivity of 0.67 and specificity of 0.79 were achieved. Spearman correlation coefficients indicated higher association between TCI propofol concentrations and UMSS (0.96) than between NI and UMSS (-0.68). CONCLUSIONS: During propofol induction in children, the Narcotrend electroencephalogram monitor was capable of following changes in the sedation level of children to some extent, but also had a relatively high probability (0.18) of incorrectly predicting changes in conscious state. Therefore, the monitor should not solely be used to guide sedation and anesthesia. NI was age-dependent and younger children had higher NI-values than older children at the same level of sedation.

Horner's syndrome secondary to internal jugular venous cannulation.

Horner's syndrome is a rare complication following insertion of a central catheter into the internal jugular vein (IJV). A 5-year-old boy, who developed unilateral Horner's syndrome postoperatively following IJV cannulation, is presented. The Horner's syndrome resolved completely after 5 months.

The analgesic efficacy of acetaminophen, ketoprofen, or their combination for pediatric surgical patients having soft tissue or orthopedic procedures.

The combined use of acetaminophen and a nonsteroidal antiinflammatory drug has been shown to provide better postoperative analgesia than either drug alone in several adult studies. However, there are no pediatric studies analyzing similar effects when the currently recommended doses of acetaminophen are used. In a double-blind, placebo-controlled design we randomized 120 children, aged 1-9 yr, undergoing orthopedic or soft tissue surgery, into 3 groups to receive either acetaminophen 60 mg/kg rectally and 40 mg/kg orally, ketoprofen 2 mg/kg IV twice, or the combination of the active drugs. The first drug doses were given at anesthetic induction and the second doses 8 h thereafter. During anesthesia all children received sevoflurane and a continuous infusion of remifentanil. Postoperative pain was evaluated by the behavioral objective pain scale (0-9) for 24 h. The rescue medication was morphine 0.05 mg/kg IV. The primary outcome variable was morphine consumption. For statistical analysis, analysis of variance, chi2 test and Kaplan-Meier survival analysis were used. Morphine requirement was less in the combination than in the acetaminophen group both in the postanesthesia care unit (2.5 +/- 1.7 versus 3.9 +/- 2.1 morphine doses) and during the 24-h postoperative follow-up (4.1 +/- 2.5 versus 5.9 +/- 2.9 morphine doses) (P < 0.05). No differences existed between the ketoprofen and the acetaminophen groups. The objective pain scale scores were lowest in the combination group both in the postanesthesia care unit and in the postoperative ward (P < 0.05). When children were divided based on their surgery, opioid requirement and pain scores were less in the combination than in the parent drug groups only after orthopedic surgery. The combination of acetaminophen 100 mg/kg and ketoprofen 4 mg/kg in a day provided better analgesia and lower pain scores after orthopedic, but not soft tissue, surgery in children.

Acetaminophen improves analgesia but does not reduce opioid requirement after major spine surgery in children and adolescents.

STUDY DESIGN: A randomized, placebo-controlled, double-blind study to evaluate the effect of intravenously (IV) administered acetaminophen on postoperative pain in children and adolescents undergoing surgery for idiopathic scoliosis or spondylolisthesis. OBJECTIVE: To evaluate effectiveness of IV-administered acetaminophen on postoperative analgesia, opioid consumption, and acetaminophen concentrations after major spine surgery in adolescents. SUMMARY OF BACKGROUND DATA: Scoliosis surgery is associated with severe postoperative pain, most commonly treated with IV-administered opioids. Nonsteroidal anti-inflammatory drugs (NSAIDs), as adjuvant to opioids, improve analgesia and reduce the need for opioids. However, by inhibiting cyclo-oxygenase enzymes peripherally, NSAIDs may inhibit bone healing. Acetaminophen, a centrally acting analgesic, does not have the adverse effects of NSAIDs and has improved analgesia in children after another orthopedic surgery. METHODS: In an institutional review board approved study, 36 American Society of Anesthesiology patient classification I to III patients of 10 to 18 years of age were analyzed. Acetaminophen 30 mg/kg, administered IV or 0.9% NaCl was administered at the end of scoliosis or spondylolisthesis surgery, and thereafter twice at 8-hour intervals. Timed blood samples for acetaminophen determination were taken between 0.25 and 20 hours after the first dose. All patients received standard propofol-remifentanil anesthesia. Pain scores (visual analogue scale [VAS], 0-10), opioid consumption, and adverse effects were recorded. RESULTS: In the surgical ward, 7 (39%) patients in the acetaminophen and 13 (72%) in the placebo group had a VAS pain score 6 or more (P < 0.05). There were fewer hours with VAS score 6 or more in the acetaminophen group compared with the placebo group (8.7% vs. 17.8% of the hours, P < 0.05). There was no difference in oxycodone consumption during the 24-hour follow-up between the 2 groups. CONCLUSION: IV-administered acetaminophen 90 mg/kg/day, adjuvant to oxycodone, did improve analgesia, but did not diminish oxycodone consumption during 24 hours after major spine surgery in children and adolescents. All acetaminophen concentrations were in nontoxic levels.

Spectral entropy as a measure of hypnosis in children.

BACKGROUND: The Datex-Ohmeda S/5 Entropy Module (Datex-Ohmeda Division, Instrumentarium Corp., Helsinki, Finland), using time-frequency balanced Spectral Entropy, is a novel tool for monitoring the hypnotic state during anesthesia. The Entropy Module produces two values, State Entropy (SE) and Response Entropy (RE), and in adults, it has been shown to measure reliably the hypnotic effects of various drugs. In children, Spectral Entropy has been only preliminary studied. The authors' aim was to study Spectral Entropy as a marker of hypnotic state during general anesthesia in infants and children. METHODS: Twenty infants (aged 1 month-1 yr) and 40 children (aged 1-15 yr) were anesthetized for surgery using standardized sevoflurane-nitrous oxide-based anesthesia. The relationships between SE, RE, or Bispectral Index (BIS) and (1) a modified Observer's Assessment of Alertness/Sedation Scale, (2) non-steady state end-tidal concentration of sevoflurane, (3) steady state end-tidal concentration of sevoflurane, and (4) hemodynamic values were calculated using prediction probability, nonlinear regression, and correlation coefficients, as appropriate. The performances of SE, RE, and BIS were compared. RESULTS: The prediction probability values (+/- SEM) of SE, RE, and BIS versus the modified Observer's Assessment of Alertness/Sedation Scale in the induction phase were 0.83 +/- 0.06, 0.88 +/- 0.06, and 0.87 +/- 0.08 for children and 0.76 +/- 0.08,0.79 +/- 0.08, and 0.73 +/- 0.10 for infants; values in the emergence phase were 0.68 +/- 0.05, 0.74 +/- 0.04, and 0.64 +/- 0.05 for children and 0.64 +/- 0.07, 0.69 +/- 0.06, and 0.72 +/- 0.06 for infants, respectively. SE, RE, and BIS values were inversely proportionally related to the end-tidal concentration of sevoflurane for children, but for infants, the correlation was much less clear. No significant correlations were found between SE, RE, or BIS values and the hemodynamic values. CONCLUSIONS: Spectral Entropy may be a useful tool for measuring the level of hypnosis in anesthetized children and seems to perform as well as BIS. In infants, the clinical usefulness of both these electroencephalogram-derived methods must be evaluated in further controlled studies.

Optimally fitted tracheal tubes decrease the probability of postextubation adverse events in children undergoing general anesthesia.

BACKGROUND: The air leak test is recommended for assessing the appropriate size of an uncuffed tracheal tube (TT) in children. Our objectives were to determine whether there is a certain threshold air leak value beyond which a higher risk for adverse events after removal of TT can be predicted and to define other risk factors related to extubation. METHODS: We enrolled 234 cases ranging from newborn to 9 years of age requiring tracheal intubation for elective or emergency surgery. General anesthesia was induced by a mask or intravenously. The TT size was calculated using the formula: [age (years)/4] + 4.5. After the induction of anesthesia, the patient's trachea was intubated and the correct position was confirmed. The attending anesthetist assessed the leak pressure. Incidences of adverse events (prolonged or barking cough, obstructed or prolonged inspiration or expiration, subcostal and sternal retractions, arterial desaturation, or laryngospasm) were recorded after removal of TT. RESULTS: Ten patients were excluded from the study. A total of 218 children underwent 224 operations under general anesthesia. Children who had an absent air leak at 25 cmH(2)O pressure had 2.8 times more adverse events during emergence from anesthesia than those with an audible air leak. Adverse events after the removal of TT were 3.7 times more likely to occur in children whose anesthesia was provided by a less experienced anesthesia trainee. CONCLUSIONS: Adverse events after removal of TT were more likely to occur in children with an absent air leak at 25 cmH(2)O pressure and in children whose anesthesia was provided by a less experienced anesthetist.