Olli A. Meretoja

Advantages of fentanyl over morphine in analgesia for ventilated newborn infants after birth: A randomized trial

OBJECTIVE To compare the efficacy and adverse effects of fentanyl or morphine analgesia during the first 2 days of life in newborn infants who underwent mechanical ventilation. STUDY DESIGN In a randomized double-blind trial, 163 infants were allocated to receive a continuous infusion of fentanyl (10.5 microg/kg over a 1-hour period followed by 1.5 microg/kg/hr) or morphine (140 microg/kg over a 1-hour period followed by 20 microg/kg/hr) for at least 24 hours. The severity of pain was assessed with physiological parameters, a behavioral pain scale, and stress hormone concentrations before and 2 and 24 hours after the start of treatment. RESULTS The analgesic effect was similar in both groups, as judged by the pain scale. Plasma adrenaline and noradrenaline concentrations decreased significantly from 0 to 24 hours in both groups. Median adrenaline decrease was 0.5 nmol/L (interquartile range [IQR] 1.1;0.0) in the fentanyl and 0.7 nmol/L (IQR 1.3;0.1) in the morphine group, noradrenaline 2.1 nmol/L (IQR 9.0;0.2), and 3.0 nmol/L (IQR 7. 5;0.3), respectively. beta-endorphin decreased significantly only in the fentanyl group ( 14 pmol/L (IQR 28; 7), P <.05). Decreased gastrointestinal motility was less frequent in the fentanyl group (23% vs 47%, P <.01). CONCLUSIONS With at least as effective analgesia as with morphine, fentanyl had fewer side effects. Fentanyl may be superior to morphine for short-term postnatal analgesia in newborn infants.

Neuromuscular block and current treatment strategies for its reversal in children.

Even though neuromuscular blocking agents are an essential part of balanced anesthesia and the risks of residual paralysis are well documented, many anesthetists seldomly monitor neuromuscular block. Classical reversal agent neostigmine is unable to antagonise a deep neuromuscular block and is rather slow to antagonise even a moderate block. These caveats may have introduced a practice to use muscle relaxants mainly for an endotracheal intubation. This review presents current views on the effects of muscle relaxants and their reversal agents in pediatric patients. This may help clinicians to reconsider the value of muscle relaxants during anesthesia in children.

Rocuronium in infants, children and adults during balanced anaesthesia

We studied 20 infants, 20 children and 20 adults during balanced anaesthesia to compare the neuromuscular blocking effects of rocuronium in these age groups. Neuromuscular function was recorded by adductor pollicis emg and a cumulative log‐probit dose‐response curve of rocuronium was established. Thereafter, full spontaneous recovery of the neuromuscular function was recorded. Onset time of the first dose of rocuronium was shorter in children than in infants or adults. The potency of rocuronium was greatest in infants and least in children; the ED50 doses (mean ± SD) being 149 ± 36 μg˙kg−1 in infants, 205 ± 52 μg˙kg−1 in children and 169 ± 47 μg˙kg−1 in adults (P<0.05 between infants and children) and the ED95 doses being 251 ± 73 μg˙kg−1, 409 ± 71 μg˙kg−1 and 350 ± 77 μg˙kg−1, respectively (P<0.05 between all groups). The emg recovery following an average 94.5 ± 4.8% neuromuscular blockade established by rocuronium was roughly similar in all study groups. Thus, one ED95 dose of rocuronium, unlike vecuronium, acts as an intermediate‐acting agent in all age groups.

The influence of the duration of isoflurane anaesthesia on neuromuscular effects of mivacurium.

Background:The pharmacodynamic profile of muscle relax‐ants is usually changed by volatile anaesthetics. These changes seem to be time‐dependent, even though few data are available to substantiate this.

Cisatracurium during halothane and balanced anaesthesia in children

Cisatracurium, 51W89, is one of the ten stereoisomers of Tracrium® which, unlike atracurium, has been reported to have a lack of histamine mediated cardiovascular effects at doses as high as 8×ED95 in adults. We compared the time‐course of neuromuscular effects of 80 μg·kg−1 or 100 μg·kg−1 cisatracurium during N2O‐O2‐halothane or N2O‐O2‐opioid anaesthesia, respectively, in 32 children 2–12 years old. Neuromuscular function was monitored by evoked adductor pollicis EMG. Even‐numbered patients (n=16) were allowed to obtain full spontaneous recovery of neuromuscular function and odd‐numbered patients (n=16) received neostigmine 45 μg·kg−1 together with glycopyrrolate at the time of 25% EMG recovery. Data are expressed as median with 10th to 90th percentile range. Cisatracurium had an onset time (time from administration to maximal effect) of 2.2 (1.7–3.8) or 2.3 (1.8–4.9) min, a clinical duration (time to 25% EMG recovery) of 34 (22–40) or 27 (24–33) min, and a spontaneous 25–75% recovery time (time from 25 to 75% EMG recovery) of 11 (9–13) or 11 (7–12) min during halothane or balanced anaesthesia, respectively (NS). Train‐of‐four ratio recovered to 0.70 in 2.5 (1.8–3.0) or 3.2 (2.1–4.3) min following neostigmine during halothane or balanced anaesthesia, respectively (NS). Changes in blood pressure or heart rate following cisatracurium were negligible. We regard cisatracurium as a safe and promising intermediate duration muscle relaxant the effects of which can easily be reversed with neostigmine.

Alfentanil and fentanyl sedation in infants and small children during cardiac catheterization

Thirty patients aged 1–23 mth received either alfentanil or fentanyl for the induction and maintenance of IV sedation during cardiac catheterization following oral flunitrazepam premedication (0.1 mg · kg−1). Patients breathed spontaneously 30 per cent oxygen in air. Both alfentanil and fentanyl abolished all reaction to pain and discomfort with minimal haemodynamic and respiratory changes. Induction doses of alfentanil and fentanyl were 20 ± 6 and 2.5 ± 1.1 (mean ± SD) μg · kg−1, respectively, and maintenance requirements 30 ± 12 and 1.5 ± 0.6 μg · kg−1 · h−1, respectively. These requirements were comparable among younger and older as well as cyanotic and acyanotic patients. The TV sedation described adds an effective method to the armamentarium of an anaesthetist working in the cardiac laboratory.RésuméTrente patients âgés de 1 à 23 mois ont reçu soit de l’alfentanil soit du fentanyl pour l’induction et le maintien de la sédation intraveineuse durant le cathétérisme cardiaque après une prémédication au flunitrazépam (0,1 mg · kg−1). Les patients respiraient spontanément 30 pour cent d’oxygène dans l’air. L’alfentanil el le fentanyl ont aboli la rèaction et la douleur avec des changements minimes tant hémodynamiques que respiratoires. Les doses d induction d’alfentanil et de fentanyl étaient respectivement 20 ± 6 et 2,5 ± 1,1 (moyenne ± SD) μg · kg−1, respectivement, et les doses de maintien étaient 30 ± 12 et 1,5 ± 0.6 μg · kg−1 · hres−1, respectivement. Ces doses étaient comparables chez les jeunes et les moins jeunes ainsi que chez les patients présentant une cyanose ou ceux qui étaient acyanotiques. La sédation intraveineuse décrite ajoute une méthode efficace à l’armatorium de l’anesthésiste ceuvrant dans le laboratoire de cardiologie.

Oral naproxen but not oral paracetamol reduces the need for rescue analgesic after adenoidectomy in children

Background:  Our aim was to show the efficacy of naproxen and paracetamol with and without pethidine on pain and nausea and vomiting after adenoidectomy. The primary outcome was the requirement of rescue analgesic for post‐operative pain and the secondary outcome was post‐operative nausea and vomiting (PONV).

Synergism between mivacurium and pancuronium in adults

Mivacurium could be a useful agent as a final dose of a muscle relaxant following pancuronium if only additivily exists between these agents. We examined the interaction between mivacurium and pancuronium in 70 patients (ASA I‐II) during propofol‐alfentanil‐N2O‐C2 anaesthesia. Neuromuscular function was monitored by adductor pollicis EMG.

PCA in paediatric orthopaedic patients: influence of a NSAID on morphine requirement

Ninety‐seven consecutive children (5‐16 years of age), who underwent a major orthopaedic operation received patient controlled analgesia (PCA) as their main therapy for postoperative pain. A Pharmacia DeltecTM pump was used with a bolus dose of 25 μg·kg−1 of morphine, a lock‐out period of 8 min, and a maximally delivered dose of 0.1 mg·kg−1 in an hour. Two‐thirds of the patients were allocated to receive a concomitant non‐steroidal anti‐inflammatory drug (NSAID), either ibuprofen 40 mg·kg−1 or diclofenac 2 mg·kg−1 daily. Individual morphine requirement varied greatly (range 0.1‐1.6 mg·kg−1 in a day) and could not be predicted preoperatively. It was 29% less in patients receiving a NSAID (0.53 ± 0.35 (SD) vs 0.75 ± 0.28 mg·kg−1 during the first postoperative day, P= 0.002). Patients age did not influence morphine requirement, but patients with nausea took 23% less morphine than other patients (P= 0.023). Postoperative nausea was more frequent in patients having a NSAID (52 vs 31%, P= 0.027). The principle of PCA made it possible to cover even a wide individual range of postoperative opioid requirement with great patient satisfaction.

Postoperative neuromuscular block following atracurium or alcuronium in children.

Postoperative neuromuscular block (NMB) was evaluated in 60 children who received randomly either atracurium or alcuronium to induce and maintain an 85–95 per cent NMB during balanced anaesthesia. The EMG-monitor was turned away from the anaesthetist 10–15 min before the end of surgery. The average NMB was comparable between the groups at the time of reversal with neostigmine 50 μg · kg−1 (84 ±9 per cent, mean ±SD) as were the NMB and the train-of-four ratio when the tracheas were extubated on a clinical basis (32 ±20 per cent and 50 ±18 per cent, respectively). Patients who had been paralyzed with atracurium arrived at the recovery room earlier and on arrival had greater train-of-four ratios than the patients paralyzed with alcuronium (P < 0.01). Time to a train-of-four ratio of > 90 per cent was significantly shorter in the atracurium group (10 ±5 min vs 26 ±15 min, P < 0.001). Thus, an intermediate-acting muscle relaxant offers a safer recovery profile of the NMB than a long-acting muscle relaxant in paediatric patients.RésuméLe bloc neuromusculaire postopératoire (NMB) a été évalué chez 60 enfants avant reçu d’une façon randomisée soil l’atracurium soil l’alcuronium afin d’induire et de maintenir un NMB de 85 à 95 pour cent lors d’ une anesthésie balancée. L’EMG fut tournée de l’anesthésiste 10 à 15 minutes avant la fin de la chirurgie. Le NMB moyen était comparable entre les groupes lors de l’antagonisme avec de la néostigmine 50 μg · kg−1 (84 ±9 pour cent, moyenne ±SD). Il en est de même pour le NMB et le rapport de train-de-quatre quand les trochées furent extubées sur une base clinique (32 ±20 pour cent et 50 ±18 pour cent respectivement). Les patients ayant été paralysés avec l’atracurium sont arrivés plus tôt à la salle de réveil et dès leur arrivée, ils ont présenté des ratios de train-de-quatre plus élevés que ceux des patients paralysés avec l’alcuronium (P < 0.01). Le temps pour atteindre un ratio de train-de-quatre >90 pour cent était significativement plus court chez le groupe atracurium (10 ±5 min vs 26 ±15 min, P < 0.001). Ainsi. un relaxant musculaire à action intermédiate offre un profil de récupération plus sécuritaire pour le NMB que celui d’un relaxant musculaire à longue action chez les patients pédiatriques.