Alpha-1-acid glycoprotein and its potential impact on local anesthetic dose in neonates.

BACKGROUND: Alpha-1-acid glycoprotein is an acute-phase protein with a high affinity for amide local anesthetics. Compared to adults, neonates have lower concentrations of this glycoprotein in plasma, and are therefore at higher risk of developing local anesthetic toxicity. Alpha-1-acid glycoprotein concentrations rise in adults after surgery as a response to stress as well as in inflammatory conditions. Previous studies have shown that concentrations of alpha-1-acid-glycoprotein in neonates vary postpartum, influenced by gestational age and mode of delivery. AIM: This study aims to determine the concentrations of alpha-1-acid glycoprotein pre- and postoperatively in neonates undergoing major surgery. This information is important for determining safe and effective dosage of local anesthetic in this vulnerable group of patients. METHODS: In this prospective observational study, 25 neonates (median 3 days of age) undergoing major surgery were included. Blood sampling was performed preoperatively and at four occasions postoperatively. Alpha-1-acid-glycoprotein plasma concentrations were analyzed using an immunoturbidimetric assay. Mann-Whitney U test, Kruskal-Wallis and Spearman ranking correlation test were used for the statistical analysis. RESULTS: Higher plasma concentrations of alpha-1-acid-glycoprotein were found 48 h postoperatively compared to preoperatively [median (inter-quartile range) 0.815 g L-1 (0.663-0.983 g L-1 ) vs. 0.300 g L-1 (0.205-0.480 g L-1 p < 0.001)], respectively. It was not possible to detect any influence of sex, postnatal age, gestational age, or delivery mode on alpha-1-acid-glycoprotein concentrations in our data. CONCLUSIONS: Alpha-1-acid-glycoprotein concentrations increase in neonates as a response to surgery regardless of gestational age, sex, or mode of delivery.

Plasma levels of levobupivacaine during continuous infusion via a wound catheter after major surgery in newborn infants: An observational study.

BACKGROUND: Epidurals may be challenging in neonatal patients due to technical difficulties relating to insertion and the risk of local anaesthesia toxicity. The use of wound catheters with an infusion of local anaesthetic has been shown to be well tolerated in adults and older children. There are few data concerning wound catheter techniques in neonatal patients. OBJECTIVES: The primary aim of this study was to analyse plasma levels of levobupivacaine associated with continuous wound infiltration via a catheter following neonatal surgical procedures. Secondary parameters, including the quality of postoperative analgesia and wound healing, were also noted. DESIGN: A prospective, observational study. SETTING: Paediatric ICU at the Karolinska University Hospital, Stockholm, Sweden, from March 2008 to December 2010. PATIENTS: Twenty newborn infants (median weight 3.48 kg) scheduled for major abdominal or thoracic surgery were included. Exclusion criteria were known or suspected hepatic dysfunction. Before skin closure, a subcutaneous catheter was inserted into the wound followed by a 0.5 mg kg(-1) bolus of levobupivacaine (0.125%, 0.4 ml kg(-1)) through the catheter. A continuous infusion was started 20 to 30 min later at a rate of 0.2 mg kg(-1)h(-1) (0.16 ml kg(-1) h(-1)). MAIN OUTCOME MEASURES: Plasma concentrations of levobupivacaine (total and unbound) at 12, 24, 48 and 72 h postoperatively. Morphine consumption, pain scores and wound healing were also analysed. RESULTS: Median concentrations of unbound and total levobupivacaine at 72 h were 0.018 and 1.305 µg ml(-1), respectively. In 18 out of 20 infants [90%; 95% confidence interval (CI) 68.3 to 98.8], the unbound plasma concentration of levobupivacaine remained relatively stable and below 0.05 µg ml(-1) throughout the 72 h observation period. Pain scores and morphine consumption levels were low. All wounds except one healed within 10 days. CONCLUSION: The studied infusion regimen was associated with plasma levels of levobupivacaine well below those associated with toxicity. Adequate wound healing, low pain scores and a reduced need for opioids were also noted.

Plasma concentrations of levobupivacaine associated with two different intermittent wound infusion regimens following surgical ductus ligation in preterm infants.

BACKGROUND: Administration of local anesthetics by a surgically placed wound catheter has recently been shown to reduce the need for postoperative morphine administration in extremely preterm infants undergoing ductus ligation. The primary aim of this randomized safety study was to define the plasma levels of levobupivacaine (LB) following two different intermittent infusion regimens. METHODS: Eighteen preterm infants 23-27 gestational weeks, median birthweight 721 g scheduled for ductus ligation were included in the study. All patients were anesthetized according to a standardized protocol based on high-dose fentanyl (25-50 µg·kg(-1) ). Before skin closure, a subcutaneous catheter was inserted into the wound. The patients were randomized to receive one of the two intermittent infusion regimens: Group BII: Initial bolus plus early start of the intermittent infusion or Group DII: No bolus plus delayed start (8 h) of the intermittent infusion. Blood samples for determination of LB plasma concentrations were obtained on six occasions during the 24-h postoperative observation period, as well as hourly postoperative pain assessments using the Echelle Douleur Inconfort Noveau (EDIN) pain scale. RESULTS: Plasma concentrations of LB ranged from 0.094 to 1.682 µg·ml(-1) and 0 to 0.549 µg·ml(-1) in group BII and DII, respectively. Both regimens were associated with low postoperative EDIN pain scores (24 h median of 0 and 1 in group BII and DII, respectively). No signs of systemic local anesthetic toxicity were noted. CONCLUSIONS: The two studied intermittent infusion regimens were associated with plasma levels below potentially toxic levels and were both associated with adequate postoperative pain scores.

Development and psychometric properties of the Swedish ALPS-Neo pain and stress assessment scale for newborn infants.

AIM: To validate and evaluate the psychometric properties of the ALPS-Neo, a new pain assessment scale created for the continuous evaluation of pain and stress in preterm and sick term infants. METHODS: A unidimensional scale for continuous pain, Astrid Lindgren Children's Hospital Pain Scale (ALPS 1), was developed further to assess continuous pain and stress in infants treated in the neonatal intensive care unit (NICU). The pain scale includes observations of five behaviours. A manual was created, clarifying the scoring criteria. An internal and an external panel assessed face validity. Psychometric properties were evaluated in three different steps. Inter-rater reliability was estimated from video-based assessments (n = 625) using weighted kappa statistics (test I). Inter-rater reliability was further evaluated in test II (n = 125) and test III (n = 96) by real-time assessments using the intraclass correlation coefficient (ICC) and Cronbach's alpha. RESULTS: The final inter-rater reliability (test III) was assessed as good with ICC 0.91 for the total score and 0.62-0.81 for the five items. Cronbach's alpha showed 0.95 for the total score. CONCLUSION: ALPS-Neo is a new assessment tool for optimising the management of pain and stress in newborn infants in the NICU. It has proved easy to implement and user-friendly, permitting fast, reliable observations with high inter-rater reliability.

[Swedish guidelines for prevention and treatment of pain in the newborn infant]. / Svenska riktlinjer för prevention och behandling av smärta hos nyfödda.

A Swedish national consensus statement concerning prevention and management of pain in the newborn infant has been prepared by members of the Swedish Paediatric Pain Society (Svensk Barnsmärtförening, SBSF). The document is based on the Consensus Statement for the Prevention and Management of Pain in the Newborn Infant by Anand et al [1].