An atypical presentation of an acute neurological illness: acute motor axonal neuropathy.

Pain is a common symptom amongst patients presenting to the Acute Medical Unit, with an extensive differential diagnosis. We present the case of a patient with back and lower limb pain where the diagnosis of an atypical form of Guillain-Barre Syndrome (GBS) was made. Acute physicians must be vigilant to the less common presentations of GBS and the variations from the "classical" presentation of ascending flaccid paralysis.

Intrathecal morphine provides effective and safe analgesia in children after cardiac surgery.

BACKGROUND: The purpose of this prospective, randomized, blinded to observer study was to assess the analgesic effect and safety of intrathecal morphine (ITM) in post-operative pain control in children after heart surgery with a sternotomy incision. METHODS: Eighty children, 3-55 kg in body weight, undergoing elective cardiac surgery with opioid-based anaesthesia were randomly divided into two treatment groups to receive either 20 micrograms/kg ITM at induction of anaesthesia or control. To standardize the protocol for administration of post-operative rescue intravenous morphine boluses and infusion (20-60 micrograms/kg/h), the Cardiac Analgesic Assessment Scale (CAAS) was used. RESULTS: Nine patients were excluded from the study after randomization. Thirty-five patients were enrolled to the ITM group and 36 to the control group. The groups were similar for demographics and intra-operative clinical characteristics. The mean time for the first intravenous morphine dose from ITM administration or equivalent time zero in the control group was significantly longer (P = 0.003) in the ITM group compared with the control group (12.3 vs. 8.7 h). Time from Paediatric Intensive Care Unit (PICU) admission to the start of intravenous morphine was also significantly longer (P = 0.01) in the ITM group (6.0 vs. 3.4 h). The total intravenous morphine consumption over the mean 19 post-operative hours was significantly lower (P = 0.03) in the ITM group. However, the use of ITM did not result in earlier extubation or earlier discharge from the PICU. Of the 35 patients who received ITM at induction of anesthesia, 20% (n = 7) did not require any additional morphine in the PICU compared with three out of 36 control group patients. This did not reach statistical significance. The incidence of adverse events was low in both groups. CONCLUSIONS: An ITM dose of 20 micrograms/kg had a significant (P = 0.03) intravenous morphine-sparing effect after cardiac surgery. Effective analgesia was observed for 12 h after administration of intrathecal morphine.

Pharmacokinetics of levobupivacaine 0.25% following caudal administration in children under 2 years of age.

BACKGROUND: Levobupivacaine, the S(-)enantiomer of racemic bupivacaine is less cardiotoxic than racemic bupivacaine and the R(+)enantiomer dexbupivacaine, while retaining similar local anaesthetic properties and potency to racemic bupivacaine. The pharmacokinetic profiles of the two bupivacaine enantiomers differs and that of racemic bupivacaine may be age dependent. We examined the pharmacokinetics of levobupivacaine after its single shot caudal epidural administration in children. METHODS: An open-label phase 2 study was undertaken to examine the pharmacokinetics of levobupivacaine 0.25% 2 mg kg(-1) in 49 children aged less than 2 yr, after single shot caudal epidural administration. Plasma concentrations were determined at intervals up to 60 min after caudal injection. RESULTS: Time to peak plasma concentration (T(max)) ranged between 5 and 60 min (median 30 min) and was reached later in children aged less than 3 months (P<0.005). Peak plasma concentration (C(max)) ranged between 0.41 and 2.12 micro g ml(-1) (median 0.80, mean (SD) 0.91 (0.40) micro g ml(-1)). CONCLUSION: After the caudal epidural administration of levobupivacaine 2 mg kg(-1) in children less than 2 yr of age, C(max) was within the accepted safe range for racemic bupivacaine. T(max) varied and occurred later in some children, particularly those aged less than 3 months. Sampling in future pharmacokinetic studies in this age group should extend beyond 60 min.

Efficacy and safety of caudal injection of levobupivacaine, 0.25%, in children under 2 years of age undergoing inguinal hernia repair, circumcision or orchidopexy.

BACKGROUND: Levobupivacaine is the S(-)-enantiomer of racemic bupivacaine. Evidence suggests that it is less cardiotoxic than racemic bupivacaine and the R(+)-enantiomer, dexbupivacaine, while retaining similar local anaesthetic properties and potency to racemic bupivacaine. METHODS: This was an open study designed to assess the efficacy and safety of 0.25% levobupivacaine administered as a caudal injection at a dose of 2 mg.kg(-1) to 49 paediatric patients aged less than 2 years old undergoing circumcision (group 1), or hernia repair or orchidopexy (group 2). RESULTS: Adequate analgesia (an increase of <20% in pulse or respiratory rate compared with baseline and an absence of gross movement on application of surgical stimulus) was achieved in 43/48 patients evaluable for efficacy (89.6%). All 22 patients in the circumcision group had adequate analgesia, and two of these patients did not require additional analgesia. The mean time to the use of additional analgesia was 7.3 h. Only one event (a mild rash) was considered possibly related to study medication. CONCLUSIONS: Levobupivacaine is a promising new local anaesthetic agent for pain management in paediatric patients and appears to offer similar anaesthetic efficacy to racemic bupivacaine with a potentially improved tolerability profile.

Randomized double-blind trial of low- and moderate-dose lidocaine regional anesthesia for forearm fractures in childhood.

We undertook a randomized double-blind trial to compare the efficacy of 1.5 mg/kg body weight (low dose) and 3 mg/kg (moderate dose) lidocaine regional anesthesia for closed reductions of forearm fractures in childhood. Of the 283 children studied, 143 were randomized to the moderate-dose group and 140 to the low-dose group. The characteristics of the children and their injuries did not differ significantly. There were no complications due to lidocaine toxicity. In children with angulated and incompletely displaced fractures, satisfactory anesthesia was achieved in 94% of those receiving the low dose and in 97% of those receiving the moderate dose of lidocaine. In children with completely displaced fractures, satisfactory anesthesia was achieved in 93% of those receiving the moderate dose but in only 67% of those receiving the low dose of lidocaine. We conclude that the low-dose lidocaine protocol is suitable for children requiring closed reductions of angulated and incompletely displaced fractures of the forearm. In contrast, the moderate-dose lidocaine protocol is more reliable in children with displaced forearm fractures. Meticulous adherence to the protocols is essential to prevent systemic lidocaine toxicity from premature deflation of the tourniquet. This potential risk is further reduced by use of the low-dose protocol, which is applicable to approximately 70% of the children with forearm fractures requiring closed reductions.

Effect of extradural analgesia on stress responses to abdominal surgery in infants.

We studied 40 children younger than 4 yr having elective abdominal surgery under general anaesthesia supplemented with either systemic opioids or extradural bupivacaine. Venous blood samples were obtained before tracheal intubation to measure baseline concentrations of adrenaline, noradrenaline, glucose, ACTH and cortisol. Additional samples were obtained 45 min after the start of surgery, at the end of surgery, 1 h and 24 h after the end of surgery. Plasma concentrations of bupivacaine were measured also in the extradural group at each sampling time. Both techniques provided acceptable analgesia, but the perioperative increases in adrenaline, glucose and ACTH were significantly greater in the opioid group. Noradrenaline concentrations decreased to less than baseline values in the extradural group and were significantly less than in the opioid group. The perioperative increase in cortisol was similar in the two groups, despite the differences in ACTH responses. Most responses returned to the baseline values within 24 h. Plasma bupivacaine concentrations remained within safe limits during the study, but systemic concentrations increased in some of the patients during postoperative infusion with 0.125% bupivacaine.

Outpatient treatment of upper extremity injuries in childhood using intravenous regional anaesthesia.

Intravenous (i.v.) regional anaesthesia was used in outpatient treatment of 400 upper extremity fractures and dislocations in children ranging in age from 3 to 16 years. All reductions were performed in the emergency department. Good analgesia was achieved in 90% of the patients, and only nine children (2.3%) had unacceptable reductions that required further treatment under general anaesthesia. Intravenous regional anaesthesia is a safe and effective procedure that facilitates outpatient treatment of upper extremity injuries in children.

Effects of vasodilators on rates of change of nasopharyngeal temperature and systemic vascular resistance during cardiopulmonary bypass in anaesthetized dogs.

The effects of various vasodilating agents on the rates of change of nasopharyngeal temperature and total systemic vascular resistance of anaesthetized dogs during cardiopulmonary bypass were studied. Intravenous administration of nitroglycerine (14 micrograms/kg per min, infused at 35 degrees C and 36 degrees C), sodium nitroprusside (5 micrograms/kg per min, infused at 36 degrees C) and phenoxybenzamine (1 mg/kg bolus, given at 32 degrees C and 36 degrees C) did not have any effect on the total cooling time or the rate of cooling from 36 degrees C to 18 degrees C. However, in dogs treated with phenoxybenzamine the time taken to rewarm to 36 degrees C was significantly shorter than those observed in the control, nitroglycerine or sodium nitroprusside treated animals. This difference in rewarming time was mainly due to the more even rate of rewarming induced by phenoxybenzamine. Moreover, a significantly greater reduction in systemic vascular resistance was observed in phenoxybenzamine treated animals than in the other treatment groups.

Plasma bupivacaine concentrations following lumbar epidural anaesthesia in children.

Plasma levels of bupivacaine were measured following lumbar epidural administration of 3 mg/kg of 0.5% plain solution in sixteen children. The peak levels were generally between 1.0 and 2 micrograms/ml, the highest being 2.9 micrograms/ml. No manifestations of toxicity were observed. There was a significant positive correlation between peak plasma levels and increasing age.

The influence of age on lignocaine pharmacokinetics in young puppies.

Eight mongrel puppies were studied at intervals of a few weeks. Lignocaine 4 mg/kg was infused over 60 seconds. Frequent samples were taken over 30 minutes for plasma lignocaine assay. Initially the concentrations were significantly higher in the oldest group (178-191 days) but after 10 minutes the youngest group (3-16 days) had significantly higher levels than the other groups. Pharmacokinetic data derived included the rate constants k21, k12 (drug movement between two compartments), k10 (elimination from the central compartment), and the volume of distribution (V beta). The elimination rate constant k10 was significantly lower in Group 1 (3-16 days) than all other groups and Group 2 (37-57 days) was lower than Group 4 (178-191 days). The calculated beta half-life was significantly longer in the youngest group than the others. There was no significant difference in the volume of distribution between these age groups--up to 6 months.

Intravenous regional anaesthesia for the treatment of upper limb injuries in childhood.

A prospective study was made of the use of intravenous regional anaesthesia for the treatment of upper limb fractures and dislocations in 200 children aged from 3 to 15 years. An aqueous solution containing 5 mg/ml of lignocaine (0.5%) was administered in a dosage of 3 mg/kgm body weight, but dosages of 2 mg/kgm were used in each arm of a child with bilateral injuries. Intravenous regional anaesthesia was well tolerated and was a safe and effective method of treating these injuries in a casualty department with adequate resuscitation facilities and staff trained in the management of local anaesthetic toxicity.

The influence of age on plasma lignocaine levels following tracheal spray in young dogs.

A study was conducted in puppies of one litter beginning before they were three weeks old and repeated up to six times in the first four months of life to determine whether any age-related changes in peak plasma lignocaine levels occurred following tracheal spray. These were significantly higher in the youngest group (less than 20 days) than in dogs 2-3 months of age. There was a significant negative correlation between peak plasma levels and age up to four months. The maximum level attained by any puppy was 4.48 ug/ml after 4 mg/kg tracheal lignocaine spray.

Plasma bupivacaine concentrations in children during caudal epidural analgesia.

Plasma bupivacaine concentrations were measured in 45 children, whose ages ranged from 4 months to 12 years, following administration of caudal epidural analgesia. Using 3 mg/kg of bupivacaine 0.25%, mean blood levels of 1.2-1.4 microgram/ml were reached, which are well within the limits of projected toxic levels. Simultaneous arterial and venous sampling showed a small but significant difference between these two sampling sites fo the first fifteen minutes.

Plasma lignocaine concentrations following topical laryngeal application.

Lignocaine 4%, 4 mg/kg, was sprayed onto the larynx and subglottic area of 96 children aged from 2 weeks to 12 years and plasma lignocaine concentrations were measured. While the majority were well within the accepted safe range (4.5 micrograms/ml) occasional concentrations over 8 micrograms/ml appeared in all groups. Simultaneous arterial and venous sampling showed a small but significant difference in the first 10 minutes.

Colonization by Salmonella typhimurium and Shigella flexneri III of the gastrointestinal tract of mice treated with beta-2-thienylalanine and streptomycin.

Mice fed beta-2-thienylalanine (beta-2-T) by oesophageal tube were no more susceptible to gastrointestinal tract colonization by Salmonella typhimurium or Shigella flexneri III than control mice fed water. In both beta-2-T-fed and water-fed groups, the increasing dosage of S. typhimurium, in logarithmic increments to groups of mice, resulted in increasing numbers of these bacteria detectable on dilution plates from organ homogenates. Colonization by S. flexneri III only occurred at a dosage of 10(8) bacteria for both groups. Pretreatment with 50 mg streptomycin allowed 10(3) Salmonella or 10(4) Shigella to colonize both beta-2-T and water-fed groups. Coliforms, inhibited by beta-2-T under certain conditions in vitro, were found in equal numbers in both groups. No obvious differences were noted in either types of other bacteria detected or numbers recovered from the two groups. No gross behavioural changes were noted in mice fed beta-2-T and not challenged with pathogenic bacteria, and no pathological changes were noted in hepatic or splenic tissues. With increasing Salmonella dosage, collections of polymorphonuclear leucocytes, which were almost focal, and increased numbers of giant cells were noted in splenic red pulp areas, in both groups.

Local anaesthetic plasma levels in children.

Blood levels of lignocaine and bupivacaine were measured in children following caudal, subcutaneous and tracheal administration. The highest peak levels were in children under 3 years following tracheal spray but all blood levels were below accepted toxic adult levels for anaesthetised patients. No toxic manifestations were seen.

Low-temperature pasteurisation of human milk.

Human milk was pasteurised at 62.5 degrees C for 30 minutes. This treatment resulted in a 99.99 percent drop in the bacterial count of the milk. Only non-pathogenic organisms remained, and both Escherichia coli and Staphylococcus aureus were destroyed. There was some reduction (less than 50 percent) of the activities of specific antibody to E. coli and lactoferrin, but lysozyme was stable and the pasteurised milk remained effective at inhibiting in vitro growth of E. coli.