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Biomedical subjects

P A Stoddart

Publications and source records attributed to P A Stoddart.

16 recordsLinked to original sources

Prospective comparison of sevoflurane and desflurane in formerly premature infants undergoing inguinal herniotomy.

BACKGROUND: Formerly premature infants having inguinal herniotomy have been at a high risk of postoperative apnoea, newer less soluble anaesthetic agents may reduce this risk. METHODS: Thirty infants, under 37 weeks gestation and under 47 weeks post-conceptional age, undergoing inguinal herniotomy had an inhalational induction with sevoflurane and were randomly allocated to sevoflurane (group S) or desflurane (group D) for maintenance. All infants received i.v. atracurium 0.5 mg kg(-1), rectal acetaminophen 20 mg kg(-1) and caudal bupivacaine 0.25% 1 ml kg(-1). Infants were monitored for apnoeas (using nasal thermistry and impedance), haemoglobin oxygen desaturations and bradycardias for 12 h before and after operation with an Alice 4 polysomnograph. Emergence timings were recorded. RESULTS: There was no difference between pre- and postoperative incidence of apnoeas in either group, and no group difference between desflurane and sevoflurane in terms of pre- and postoperative ventilatory events or in the number of apnoeas in the postoperative period (nine patients in group D and five patients in group S had apnoeas). Median times to first movement, tracheal extubation, eye opening and first cry were all faster with group D (group D: 3.0, 10.0, 9.0 and 11.0 min and group S: 7.0, 15.1, 13.5 and 16.1 min, respectively). No infant had problems with airway irritation on emergence and no infant required airway intervention for apnoea. CONCLUSIONS: Infants wake faster from general anaesthesia when maintained with desflurane as compared with sevoflurane, but no difference in postoperative respiratory events was demonstrated between the groups.

Anesthesia Recovery Period↗

Emergence and recovery in children after desflurane and isoflurane anaesthesia: effect of anaesthetic duration.

BACKGROUND: We hypothesized that increasing duration of inhalation anaesthesia is associated with slower emergence and recovery in children, and that this effect would be less marked with desflurane in comparison with isoflurane. METHODS: Fifty-four infants and children assigned in groups according to age and expected length of operation were prospectively randomized to receive either isoflurane (I) or desflurane (D) for anaesthesia. After standard induction, the anaesthesia was maintained using an age-related 1.0 minimum alveolar concentration (MAC) equivalent for either agent in air and oxygen. Local analgesia was used as appropriate. End-tidal volatile agent concentration was recorded until extubation. Clinical evaluation of recovery was made by observers, blinded to group allocation. RESULTS: For patients <4 yr of age, the median (95% CI) times in minutes to first movement [5.27 (D), 9.22 (I)], eye opening [9.42(D), 13.3(I)] and extubation [7.18 (D), 12.5 (I)] were significantly shorter (P<0.05) for desflurane. In the group >4 yr of age, the median (95% CI) times in minutes to first movement [4.42 (D), 11.6 (I)], eye opening [8.55(D), 18.0(I)] and extubation [7.08 (D), 16.7 (I)] were significantly shorter (P<0.001) for desflurane. Times to leave recovery were not significantly different for the group <4 yr of age, but were significantly shorter for desflurane in the group >4 yr of age (P<0.01). The isoflurane, but not desflurane, had a time-dependent effect on arousal. There were no significant differences in incidence of airway irritation or emergence delirium between the two agents. CONCLUSIONS: The rate of recovery in children after exposure to desflurane was faster than those patients receiving isoflurane; recovery from desflurane, but not isoflurane, was relatively unaffected by the duration of anaesthesia.

Age Factors↗

Double-blind randomized controlled trial of caudal versus intravenous S(+)-ketamine for supplementation of caudal analgesia in children.

BACKGROUND: The postoperative analgesic efficacy of S(+)-ketamine after caudal or i.v. administration following sub-umbilical surgery in children was studied to investigate its principal site of analgesic action. METHODS: Sixty children undergoing caudal block during general anaesthesia for hernia repair or orchidopexy were prospectively randomized to one of three groups: the bupivicaine group received plain bupivacaine 0.25% 1 ml x kg(-1); the caudal ketamine group received caudal plain bupivacaine 0.25% 1 ml x kg(-1) with S(+)-ketamine 0.5 mg x kg(-1); the i.v. ketamine group received caudal plain bupivacaine 0.25% 1 ml x kg(-1) plus S(+)-ketamine 0.5 mg x kg(-1) i.v. Postoperative measurements included analgesic requirements and modified objective pain score for the first 24 h. RESULTS: The median time to first analgesia was significantly longer in the caudal ketamine group (10 h) than in the i.v. ketamine (4.63 h) or bupivacaine (4.75 h) groups (P=0.01). Significantly fewer doses of analgesia were required over the first postoperative 24 h by subjects in the caudal ketamine group (median 1) compared with the i.v. ketamine (median 2) or bupivacaine (median 2.5) groups (P<0.05). There was no difference between the groups in the incidence of postoperative nausea and vomiting or psychomotor reactions. CONCLUSIONS: We have demonstrated that the addition of caudal S(+)-ketamine to bupivacaine prolongs the duration of postoperative analgesia. However, the same dose of i.v. S(+)-ketamine combined with a plain bupivacaine caudal provides no better analgesia than caudal bupivacaine alone, indicating that the principal analgesic effect of caudal S(+)-ketamine results from a local neuroaxial rather than a systemic effect.

Analgesia, Epidural↗

Double-blind randomized placebo-controlled trial of the effect of ketamine on postoperative morphine consumption in children following appendicectomy.

BACKGROUND: Ketamine has an opioid sparing effect following surgery in adults. This study investigated whether a similar effect is seen following appendicectomy in paediatric patients. METHODS: Seventy-five ASA 1 or 2 children aged 7-16 years were recruited, and randomly allocated to one of three groups. Following a standard anaesthetic for appendicectomy, all were prescribed patient controlled analgesia (PCA) morphine with paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDS) as required for postoperative analgesia. In addition the control group received a saline infusion postoperatively, the ketamine bolus group received 500 micro g.kg-1 intravenous (i.v.) ketamine preincision and a saline infusion postoperatively, and the ketamine infusion group received 500 micro g.kg-1 i.v. ketamine preincision and a ketamine infusion at 4 micro g.kg-1 min-1 postoperatively. Morphine consumption, rescue analgesia requirement and side-effects were recorded postoperatively. RESULTS: There was no difference in morphine consumption between the groups. The ketamine infusion group required more doses of rescue analgesia and reported more side-effects than the control group. Five patients, all in the ketamine infusion group, reported hallucinations. CONCLUSIONS: In this paediatric population intravenous ketamine did not have a morphine sparing effect. The increased incidence of side-effects, especially hallucinations, reported by patients given a ketamine infusion may limit the further use of postoperative ketamine in children.

Adolescent↗

Double-blind, placebo-controlled analgesic study of ibuprofen or rofecoxib in combination with paracetamol for tonsillectomy in children.

BACKGROUND: The analgesics used for paediatric tonsillectomy may be associated with side-effects such as sedation, respiratory depression and vomiting (opioids) or increased bleeding [non-steroidal anti-inflammatory drugs (NSAIDs)]. In our institution, we employ a combination of paracetamol, NSAID and opioid, although there is no published evidence of analgesic benefit from adding NSAIDs to paracetamol in children. METHODS: This randomized, double-blinded clinical study examined the analgesic effectiveness of combining paracetamol (20 mg kg(-1)) with rofecoxib (0.625 mg kg(-1)), ibuprofen (5 mg kg(-1)) or placebo as premedication for (adeno)tonsillectomy (n=98) in children aged 3-15 yr. Intravenous fentanyl 1-2 microg kg(-1) was given intraoperatively. Regular oral paracetamol (15 mg kg(-1), 4 hourly) was given after operation and could be supplemented on request from the child with oral ibuprofen 5 mg kg(-1) or oral codeine 1 mg kg(-1). The primary outcome variable was need for early supplementary analgesia (within 2 h after surgery). RESULTS: The addition of ibuprofen to paracetamol reduced the need for early analgesia from 72% to 38% of children (difference 34%; 95% confidence interval 4-64%). The addition of rofecoxib to paracetamol did not significantly alter the need for early analgesia (68 vs 72%). Pain scores were higher in those children who required early analgesia. There were no differences between the groups in operative blood loss or complications, total 24-h analgesic consumption, pain scores at 4 and 8 h, vomiting or antiemetic use. CONCLUSION: This study provides evidence to support the combination of ibuprofen (but not rofecoxib) with paracetamol for perioperative analgesia in children.

Acetaminophen↗

Rapid skin anaesthesia using high velocity lignocaine particles: a prospective placebo controlled trial.

BACKGROUND: Local anaesthetic creams (EMLA and Ametop) are used widely to provide pain free intravenous cannulation. However, they take a minimum of 45 minutes to become effective. AIMS: To evaluate a prototype device, dermal Powderject lidocaine (DPL), that delivers high velocity lignocaine particles into the skin. METHODS: A total of 132 children (aged 4-12 years) were randomised to receive either a sham delivery or a delivery of DPL on the skin at the antecubital fossa, or back of hand. Pain of intravenous cannulation was assessed four minutes later using self reporting behaviours and blinded observation with standard pain assessment tools. The trial was designed to measure both efficacy of skin anaesthesia and potential skin damage with increasing driving pressure of the device (30 or 40 bar), and different lignocaine particle sizes (<38 micrometer or 38-53 micrometer) in a block randomised fashion. RESULTS: A total of 128 patients were evaluable. There was a trend towards improved anaesthesia at higher device pressures at the antecubital fossa with both self reporting and blinded observation. Acceptable analgesia was achieved in 90% of patients for high pressure at both particle sizes compared to 60% and 40% for the sham device using self reporting measures. The observed differences using the blinded observer were similar: 90% v 20% (40 bar and small particles v sham), and 80% v 40% (40 bar and large particles v sham). At the back of hand the differences between active and sham devices were not significant. The device was well tolerated and not associated with pain on deployment. One patient had mild petechiae and oedema after deployment (Draize score of 3). CONCLUSIONS: This prototype device appears to provide significant skin anaesthesia at the antecubital fossa, but not at the back of hand. The device is not painful to use and causes only minor short term skin changes.

Anesthesia, Dental↗

Post-operative recovery after inguinal herniotomy in ex-premature infants: comparison between sevoflurane and spinal anaesthesia.

We prospectively studied the post-operative recovery profile of 28 ex-premature infants undergoing inguinal herniotomy. All infants had a post-conceptual age of less than 46 weeks at the time of surgery and were randomized to receive either sevoflurane (group 1, 14 patients) or spinal anaesthesia (group 2, 14 patients). All patients received supplemental caudal analgesia before skin incision. Cardiorespiratory function was continuously recorded in all patients before and after surgery. A blinded observer analysed each paired recording for predefined episodes of apnoea, hypoxaemia or bradycardia and the reports were used to compare the two groups. Spinal anaesthesia was attempted unsuccessfully in four patients in group 2. Five patients in group 1 demonstrated an 'excess' number of episodes (median 4, range 3-12) of clinically silent post-operative cardiorespiratory complications. ('Excess' in our study was defined as a 3-fold or greater increase in the number of post-operative episodes of bradycardia or apnoea relative to pre-operative occurrence). Three of these patients had pre-existing abnormal respiratory function and accounted for 80% of the episodes (26/32) of post-operative bradycardia and all five episodes of post-operative apnoea identified. All episodes of bradycardia and apnoea were temporally unrelated. None of the remaining patients in group 2 demonstrated an unacceptable number of post-operative cardiorespiratory complications. Our limited study suggests that general anaesthesia with an inhalational agent such as sevoflurane may induce or unmask abnormalities of cardiopulmonary function in predisposed infants. Spinal anaesthesia may be preferable but it is potentially stressful for the infant and associated with a clinically significant failure rate.

Anesthesia, Spinal↗

Onset of neuromuscular blockade and intubating conditions one minute after the administration of rocuronium in children.

In a blinded randomized study intubating conditions were compared at one min following intravenous induction with propofol and either suxamethonium 1.0 mg.kg-1, or rocuronium 0.6 mg.kg-1. Onset time to maximal twitch depression, % block at one minute and clinical duration (time to 25% recovery) were measured. Sixty children undergoing elective tonsillectomy were recruited. Onset time [42s (SD 11s)] and clinical duration [3.3 min (SD 1.0 min)] in the suxamethonium group was significantly (P < 0.001) less than in the rocuronium group [92s (41s)] and [24.2 min (6.6 min)] respectively. The median twitch height at one minute for suxamethonium was 0% (range 0-8%) and significantly greater (P < 0.001) at 5% (range 0-22%) for rocuronium. Despite this there was no difference in the intubating conditions at one minute with 25 excellent/5 good in the suxamethonium group and 27 excellent/3 good in the rocuronium group. We conclude that rocuronium 0.6 mg.kg-1 gives optimal intubating conditions at one minute in children.

Androstanols↗

A comparison of 4.5% human albumin solution and Haemaccel in neonates undergoing major surgery.

In a randomized blinded study we compared two colloid solutions in 30 neonates undergoing major surgery. Fifteen neonates received 4.5% Human albumin solution (HAS) (mean volume 25.6 ml.kg-1, SD 9.5) and the others received Haemaccel (Hoechst) (24.9 ml.kg-1, SD 10). Pre and postoperative plasma albumin and haemoglobin concentrations and plasma colloid osmotic pressure (COP) were compared. In the group given Haemaccel there was an appreciable and statistically significant decrease in the mean plasma albumin concentration from 34.27 to 28.27 g.1(-1) (mean difference 6, CI 3.38 to 8.62) and the mean COP decreased significantly from 22.2 to 19.9 mmHg (mean difference 2.3, CI 0.3 to 4.5). In the HAS group there was no significant change in either the plasma albumin concentration or COP. There was a small but significant decrease in the mean haemoglobin concentration from 15.92 to 14.35 g.dl-1 (mean difference 1.56, CI 0.57 to 2.55) after HAS. We conclude that HAS is the superior colloid for volume replacement in neonates undergoing surgery.

Hemoglobins↗

Serum fluoride concentration and urine osmolality after enflurane and sevoflurane anesthesia in male volunteers.

The purpose of this study was to measure the serum fluoride concentration after enflurane or sevoflurane anesthesia and to compare the effects of prolonged anesthesia with these drugs on renal concentrating function in male volunteers. The study was subdivided into three stages; an ascending dose study of 3.0 and 6.0 minimum alveolar anesthetic concentration (MAC) hours of sevoflurane alone, a 6.0-MAC-hour comparison of enflurane and sevoflurane, and a 9.0-MAC-hour comparison of enflurane and sevoflurane. Renal concentrating function was assessed by an 18-h period of fluid deprivation and the serum fluoride concentration was measured at intervals until 60 h postanesthesia. The maximum serum fluoride concentration was greater in the volunteers exposed to sevoflurane and reached a peak in the 9-MAC-hour sevoflurane group of 36.6 microM (SD 4.3) compared with 27.5 microM (SD 2.6) in the 9-MAC-hour enflurane group. However, the rapid decrease in the serum fluoride concentration after sevoflurane was such that there was no difference between the areas under the fluoride concentration-time curves. There were no significant differences between the median maximum urine osmolalities after enflurane or sevoflurane anesthesia. Prolonged anesthesia with enflurane or sevoflurane is not associated with impaired renal concentrating function despite an increase in the serum fluoride concentration.

Adolescent↗

Postal survey of paediatric practice and training among consultant anaesthetists in the UK.

A postal survey of previous paediatric anaesthetic training, current paediatric experience and management of an infant pyloromyotomy was undertaken among consultant anaesthetists in the UK. A total of 851 questionnaires were returned, giving a response rate of 31%; 352 (41%) consultants had at least one paediatric list each week, 180 (21%) anaesthetized more than one infant less than 6 months old each month and 373 (44%) had obtained more than 6 months' specialist training. Consultants trained most recently had received significantly longer (P < 0.001) specialist training than their senior colleagues: 558 (66%) consultants dealt with infants requiring a pyloromyotomy, 348 with one or two cases annually. Two-thirds preferred to use an i.v. induction technique and less than half used cricoid pressure. Choice of technique was related to the duration of specialist paediatric training and when it was received, but not to current paediatric anaesthetic experience. The results are discussed in relation to recently published recommendations on paediatric anaesthetic services.

Anesthesia↗

A comparison of epidural diamorphine with intravenous patient-controlled analgesia using the Baxter infusor following caesarean section.

In a randomised study of analgesia following Caesarean section, we compared the efficacy and side effects of on-demand epidural diamorphine 2.5 mg with intravenous patient-controlled analgesia using diamorphine from the Baxter infusor system. Pain scores fell more rapidly in the epidural group, but by the fourth hour, and thereafter, both techniques had a similar analgesic effect. The patient-controlled analgesia group used significantly more diamorphine (p < 0.001), median 62 mg (range 18-120 mg) compared to the epidural group, median 10 mg (range 2.5-20 mg), over a significantly longer time period (p < 0.001), median 54.25 h (range 38-68 h) compared to the epidural group, median 40.75 h (range 6-70 h). The frequency and severity of nausea, vomiting and pruritus were similar in the two groups, however, the patient-controlled analgesia group were more sedated during the first postoperative day. This reached statistical significance (p < 0.05) between 9-24 h. Overall satisfaction scores (0-100) were high, but the patient-controlled analgesia group scored significantly higher: mean 85.5 (SD 12.2) compared to mean 77.0 (SD 11.7) in the epidural group.

Adult↗