Gastric fluid measurement by blind aspiration in paediatric patients: A gastroscopic evaluation

Purpose

Numerous investigators have estimated gastric fluid volume using blind aspiration through multi-onficed catheters, but none have confirmed the validity of this technique in infants and children. We sought to validate the accuracy of this technique in a fasted paediatric population by using gastroscopy. Data from several studies were then combined to generate a gastric fluid volume frequency distribution for healthy paediatric patients fasted for surgery.

Methods

This is a prospective study of 17 patients aged six months to 11 yr who underwent elective upper endoscopy at a paediatric teaching hospital. Gastric contents were aspirated blindly with a syringe and a 16 or 18F multi-orificed orogastric tube, and the volume of gastric contents removed in the supine and decubitus positions was measured. Residual gastric fluid was aspirated using an endoscope. Data from 611 infants and children enrolled in previously published stuthes utilizing the same blind aspiration technique were pooled and a gastric fluid volume frequency distribution was created.

Results

Blind aspiration removed 97 ± 8% of the total gastric fluid volume. In 661 children presenting for elective surgery, the gastnc fluid volume was 0.40 ± 0.45 ml·kg^?1. Median volume was 0.27 ml · kg^?1, with the 95%ile at 1.25 ml · kg^?1 and an upper limit of 4.1 ml-kg^?1.

Conclusion

Blind aspiration of gastric contents accurately estimates gastric fluid volume for paediatric patients fasted for surgery. Population estimates for gastric fluid volume in otherwise healthy fasted paediatric patients are shown.     

Ropivacainevs bupivacaine in major surgery in infants

Purpose

To assess and compare the onset time and duration of neuroblockade obtained after ropivacaine or bupivacaine in infants undergoing major abdominal surgery. We also evaluated the efficacy and safety of employing ropivacaine instead of bupivacaine to provide operative anesthesia and postoperative analgesia.

Methods

In a prospective double blind study 28 infants, aged 1–12 months, undergoing elective major abdominal surgery, were randomly allocated to receive, after induction of general anesthesia, either 0.7 ml· kg^?1 bupivacaine 0.25% (group B) or ropivacaine 0.2% (group R) via lumbar epidural block. The onset time, total surgical time and duration of analgesia were recorded.

Results

No differences were noted in demographic data, hemodynamic variables or duration of surgery. The onset time for sensory blockade was 13.1 min ± 2.1 (group B) and 11.7 ± 2.4 min (group R). The duration of analgesia was 491 ± 291 (group R) and 456 min ± 247 (group B). Eight patients in group B and six in group R needed codeine and acetaminophen rescue on at least one occasion during the 24 hr study period. No major side effects were noted in either groups.

Conclusions

In infants undergoing major abdominal surgery under combined epidural/light general anesthesia, ropivacaine 0.2% produces sensory and motor blockade similar in onset, duration of action and efficacy to that obtained from an equal volume, 0.7 ml· kg^?1, of bupivacaine 0.25%.     

A comparison of ondansetron and prochlorperazine for the prevention of nàusea and vomiting after tympanoplasty

Purpose

To evaluate the effects on PONV and headache after tympanoplasty of prochlorperazine 0.2 mg·kg^?1 im, ondansetron 0.06 mg·kg^?1 iv or placebo (isotonic saline) 0.02 ml·kg^?1 iv given immediately after induction of anaesthesia prior to tracheal intubation.

Methods

The study was randomised, double blind and prospective. One hundred and forty-eight patients, aged 9–61 yr, received a standardised balanced inhalational anaesthetic with controlled ventilation and induced hypotension. Postoperatively, the frequencies of retching and vomiting in the PACU and of nausea, retching, vomiting, headache, analgesic and antiemetic requirements in the surgical ward for 24 hr were recorded.

Results

The four test groups (n = 37 each) were comparable. The incidences of vomiting in the PACU were similar. During the first 24 hr after surgery the antiemetics produced no reductions in the incidence of nausea alone or of vomiting alone. However, the combination of nausea and vomiting was reduced from 53% (placebo) to 16% (P < 0.0005), 19% (P < 0.0005) and 30% (P < 0.05) by im. prochlorperazine, iv ondansetron and iv prochlorperazine, respectively. The frequency of those experiencing no PONV was increased from 27% (placebo) by prochlorperazine im to 57% (P < 0.01), by ondansetron iv to 62% (P < 0.005) and by prochlorperazine iv to 43% (P = NS). The. onset of PONV was delayed in those given prochlorperazine im, and vomiting was less severe in those given ondansetron iv. Headache occurred with similar frequency in each group.

Conclusion

Prophylactic prochlorperazine 0.2 mg·kg^?1 im and ondansetron 0.06 mg·kg^?1 iv are similarly efficacious in reducing nausea with vomiting after tympanoplasty, while prochlorperazine 0.1 mg·kg^?1 iv is less efficacious. Neither drug given as described appeared to reduce the frequency of postoperative nausea alone or vomiting alone.     

Serum bupivacaine concentrations during continuous extrapleural infusion

Purpose

To determine the rate of increase in serum bupivacaine concentration during continuous extrapleural infusion.

Methods

After thoracotomy for lobectomy under general anaesthesia, nine patients had an extrapleural catheter inserted, before chest closure, in a costovertebral gutter constructed surgically by lifting the panetal pleura. Bupivacaine 0.5% with epinephnne 1:200.000 was injected through the catheter as 0.3 ml·kg^?1 bolus followed by 0.1 ml· kg^?1·hr^?1 for five days. Serum bupivacaine (free and total), albumin, alpha-1 acid glycoprotein concentrations were measured 15 min after injection and at 24 hr intervals for five days. Bupivacaine concentrations were determined by column liquid chromatography using solid phase extraction. Serum alpha-1 acid glycoprotem concentration was determined by nephelometry on QM 300 protein analyzer. Serum albumin concentration was determined by bromocresol green dye binding procedure on Hitachi 717 Autoanalyzer.

Results

A continuous elevation in total serum bupivacaine was observed, with an average value of 0.75 μg· ml on day 1 to 2.77 μg· ml on day 4 (P< 0.05). There was no increase in postoperative free serum bupivacaine concentration; average value of 177 pcg· ml^?1 on day 1 and 249 pcgml^?1 on day 4 (P=0.92). Postoperative serum alpha-1 acid glycoprotein concentration showed a steady rise with an average value of 0.94 μg· ml^?1 on day 1 and 1.47 μg·ml^?1 on day 4 (P< 0.05). No change was observed in post-operative serum albumin with an average value of 31.4 g· l^?1 on day 1 and 31.3 g· l^?1 on day 4.

Conclusion

Continuous extrapleural infusion of bupivacaine over five days after thoracotomy is associated with a steady increase in total serum bupivacaine concentration and no elevation in free serum bupivacaine concentration.     

Heart rate and cardiac output after atropine in anaesthetised infants and children

Purpose

Heart rate is considered to be a major determinant of cardiac output in infants and small children but the relationships between age, heart, rate and cardiac output in humans have never been clearly established. This study was designed to determine the change in cardiac output following atropine iv to anaesthetised infants and small children. Methods: Following-,Institutional Ethics Committee approval and written-informed consent, 20 ASA l or ll unpremeditated patients aged from 1 to 36 mo were studied. Anaesthesia was induced with 5 mg · kg^?1 thiopentone, 2 μg · kg^?1 fentanyl and maintained with halothane 0.5% in nitrous oxide 66% in oxygen. Vecuronium, 0.1 mg · kg^?1 was used to provide muscular relaxation. Cardiac output was measured by non-invasive transthoracic blind continuous-wave Doppler echocardiography before and after the administration of 0.02 mg·kg^?1 atropine iv.

Resulits

Atropine increased both heart rate and cardiac index by 31.1 ± 12.8% and 29.4 ± 17.3% respectively (P < 0.05). The cardiac index before atropine was 5.1 ± 1.2 L.min^?1m^?2 and the increase after atropine varied widely from 1,4 to 52.1%. Although atropine did not alter the overall stroke index the recorded changes ranged from -20.8 to + 18.0%. There was no association between age and either cardiac index or % change in cardiac index after atropine. However, there was a positive but weak correlation between percentage change in heart rate and cardiac output (r²=0.46).

Conclusion

Atropine causes a variable increase in cardiac output in infants and children aged between 1 and 36 mo. The change in cardiac,output, considering the limits of the transthoracic echocardiography methodology, suggests that this is related to the increase in heart rate but is not dependent of age.     

Bupivacaine decreases epidural meperidine requirements after abdominal surgery

Purpose

The purpose of this study was to determine the optimal of three concentrations of bupivacaine (0.0%. 0.05%. 0.10%) to add to an epidural infusion of mependine (1 mg· ml¹) for postoperative pain relief.

Methods

In this prospective, double blind study. 60 patients undergoing abdominal surgery with general anaesthesia were randomized into three groups to receive for postoperative epidural analgesia: 1) 1 mg· ml¹ mependine (0% group). 2) bupivacaine 0.05% and 1 mgml mependine (0.05% group). 3) bupivacaine 0.10% and 1 mg· ml mependine (0 10% group). Postoperatively, the epidural infusion rate was titrated to produce adequate analgesia and pain was assessed at rest and on movement.

Results

There were no differences in demographic data, average pain scores or side effects among the three groups. However, there was improvement of pain relief at rest over time in the three groups (P< 0.05). Postoperative epidural analgesic infusion rates increased over time for the three groups (P< 0.05) and were lower in the 0.10% group (mean of 10.0 ml· hr^?1 than in the 0% group (mean of 12.6 ml·hr¹) (P< 0.05). More than half of the 0% group had serum mependine concentrations >400 g· L^?1 to control moderate postoperative pain.

Conclusion

Although analgesia was identical among groups, the lower serum concentrations of mependine support the addition of bupivacaine 0.10% to mependine when administered as a continuous infusion following abdominal surgery.     

Rocuronium prevents succinylcholine-induced fasciculations

Purpose

The aim of this study was to assess the effect of rocuronium pretreatment at 3 and 1.5 min before succinylcholine administration on fasciculations, neuromuscular blockade and intubating conditions.

Methods

Sixty ASA I or II adults scheduled for elective surgery were anaesthetised with midazolam, fentanyl, propofol, N₂O and isoflurane. They were randomised in a double blind manner into three groups: group ROC-3 min (n = 22) received 0.05 mg·kg^?1 rocuronium, 3 min before 2 mg·kg^?1 succinylcholine; group ROC-1.5 min (n = 20) received 0.05 mg·kg^?1 rocuronium 1.5 min before 2 mg·kg^?1 succinylcholine; and group NO ROC (n = 18) had no rocuronium before injection of 2 mg·kg^?1 succinylcholine. Fasciculations and intubating conditions were evaluated by the same physician who was unaware of the randomisation. Neuromuscular block was measured at the adductor pollicis with an accelerometer.

Results

The incidence of fasciculations was lower in the ROC-3 min (9%) and ROC-1.5 mm (30%) groups than in the NO ROC group (83%;P < 0.001 ). The intensity of fasciculations was also less in both pretreatment groups. No statistical difference was noted between pretreatment at 3 and 1.5 min. Intubating conditions, onset time and duration of succinylcholine blockade were comparable in all three groups.

Conclusion

The incidence and severity of succinylcholine fasciculations can be reduced by giving 0.05 mg·kg^?1 rocuronium either 1.5 min or 3 min before succinylcholine. The effects of 2 mg·kg^?1 succinylcholine with rocuronium pretreatment, and 1 mg·kg^?1 succinylcholine, without pretreatment, are similar with respect to intubating conditions, onset of paralysis and duration of blockade.     

Inhibition of cerebral metabolic and circulatory responses to nitrous oxide by 6-hydroxydopamine in dogs

Purpose

To determine whether cerebral metabolic and circulatory consequences of N₂O result from activation of the sympathoadrenal system. The effects of pretreatment with intracistemal injection of 6-OHDA, which produces chemical sympathectomy, were studied in dogs.

Method

Seven days before measurement dogs were pretreated with intracisternal injection of either saline vehicle (sham-group) or 100 μg· kg^?1 6-hydroxydopamine (6-OHDA group). Cerebral blood flow (CBF) was measured using an electromagnetic flow-meter probe and cerebral metabolic rate for oxygen (CMRO₂) was calculated as the product of CBF and arterial-sagittal sinus blood oxygen content difference [C(a-v)O₂].

Results

In the sham group, N₂O (60%) increased CMRO₂ from 6.11 ± 0.21 ml· 100 g^?1· min^?1 to 7.10 ± 0.39 ml· 100g^?1· min^?1 and CBF from 63 ± 5 ml· 100 g^?1 · min^?1 to 173 ± 26 ml· 100 g^?1· min^?1. In the 6-OHDA group, CMRO₂ did not change during N₂O exposure, whereas CBF increased from 61 ± 3 ml· 100 g^?1· min^?1 to 135 ±19 ml· 100 g^?1· min^?1 but less then in the sham group. The 6-OHDA group displayed a reduction in cortical noradrenaline (NA) concentration from 263.2 ± 35.6 ng·g^?1 to 102.7 ± 16.5 ng· g^?1. Cortical dopamine (DA) concentration was not affected by 6-OHDA administration.

Conclusion

These results suggest that most of the increase in CMRO₂ and, at least a part of, the increase in CBF during N₂O exposure in the sham-group are related to sympathoadrenal-stimulating effects of N₂O.     

Extra-uterine renal growth in preterm infants: Oligonephropathy and prematurity

Background

Nephron number in humans is determined during fetal life. The objective of this study was to investigate the effects of preterm birth on nephron number using renal volume as a surrogate for nephron number.

Methods

This observational study was conducted over 12 months in a tertiary perinatal center. Preterm babies less than 32 weeks of gestation were recruited and followed until discharge. Term infants were recruited for comparison. The babies underwent renal sonography and renal function measurements at 32 and 38 weeks corrected age. The primary outcome measurement was total kidney volume at 38 weeks and the secondary outcome was estimated glomerular filtration rate (eGFR).

Results

Forty-four preterm infants and 24 term infants were recruited. At 38 weeks corrected age, premature infants had lower total kidney volume than term infants (21.6?±?5.7 vs. 25.2?±?5.7 ml; p?=?0.02) and a significantly lower eGFR (73.6 [IQR 68.1–77.6] vs. 79.3 [IQR 72.5–86.6] ml·min^?1·1.73 m^?2; p?=?0.03). There was a significant correlation between total kidney volume and eGFR in premature and term babies.

Conclusions

Premature infants have smaller kidney volume and likely decreased nephron number and lower estimated glomerulofiltration rate relative to infants born at term.     

Dose-response of flurbiprofen on postoperative pain and emesis after paediatric strabismus surgery

Purpose

Intravenous flurbiprofen, a non-steroidal antiinflammatory drug (NSAID), has been used recently for postoperative pain relief in adults. The drug is also likely to have antiemetic property. The present study was undertaken to investigate the effect of flurbiprofen on postoperative pain and emesis in children undergoing strabismus surgery, which is well known to produce postoperative nausea and vomiting.

Methods

In a prospective, randomised, controlled dinical trial, 90 children aged 2–11 yr received saline (control), flurbiprofen 0.5 mg · kg^?1, or flurbiprofen 1 mg · kg^?1. Saline and flurbiprofen were administered iv immediately after induction of anaesthesia. Anaesthesia was induced and maintained with sevoflurane and nitrous oxide in oxygen. Postoperative pain was assessed by a blinded observer using an objective pain scale (OPS). No opioids or antiemetics were administered throughout the study. The incidence and frequency of vomiting were compared among groups.

Results

Flurbiprofen 1 mg · kg^?1 provided lower OPS (highest) scores during the eight hours after surgery and a reduced requirement for postoperative supplementary analgesic (diclofenac suppository) compared with the other two regimens. The two doses of flurbiprofen failed to decrease the incidence and frequency of vomiting.

Conclusion

These data suggest that preoperative flurbiprofen 1 mg · kg^?1 iv is a simple and effective approach to postoperative pain relief but not to the prevention of emesis following paediatric strabismus surgery.     

Cigarette smoking does not affect thiopentone pharmacodynamic or pharmacokinetic behaviour

Purpose

Smoking affects the pharmacodynamic and pharmacokinetic behaviour of several drugs. In smokers, induction of anaesthesia is often stormy. In this study we have determined whether cigarette smoking affected thiopentone pharmacodynamic or pharmacokinetic behaviour during induction of anaesthesia.

Methods

Fifteen smokers and 15 non-smokers, scheduled for elective surgery, were studied. Heart rate, invasive arterial pressures and middle latency auditory evoked potentials were recorded awake and during thiopentone induction (9 mg·kg^?1 lean body mass), before and after tracheal intubation. Blood was sampled up to 24 hr after induction to measure thiopentone plasma concentrations and to calculate pharmacokinetic parameters.

Results

Anaesthesia was adequate in all patients, although haemodynamic intubation response was not blunted. Latencies or amplitudes of middle latency auditory evoked potentials (MLAEP) did not differ between the groups. The postintubation latencies of Nb waves were 48.9 ± 8.1 msec (mean ± SD) in smokers and 48.1 ± 8.5 msec in nonsmokers. Pharmacokinetic data showed no differences between smokers and non-smokers. Clearance of thiopentone was 2.9 ± 1.1 ml·min^?1 ·kg^?1 in smokers and 3.3 ± 1.0 ml·min^?1 ·kg^?1 in non-smokers and elimination half life of thiopentone was 12.5 ± 6.3 hr in smokers and 10.7 ± 3.1 hr in non-smokers, respectively. The haemodynamic response after the induction dose of thiopentone and after tracheal intubation were similar in smokers and non-smokers. Mean postintubation systolic arterial pressures were 192 ± 35 vs 189 ± 20 mmHg and mean postintubation heart rates were 103 ± 12 vs 102 ± 17 beat per minute (bpm) in smokers and non-smokers, respectively.

Conclusion

We conclude, that cigarette smoking does not affect the pharmacodynamic or pharmacokinetic behaviour of thiopentone.     

Conscious sedation for interventional neuroradiology: a comparison of midazolam and propofol infusion

Purpose

The aim of this study was to compare two conscious sedation techniques, midazolam (M) and propofol (P), for interventional neuroradiology by assessment of the incidence of complications and satisfaction scores.

Methods

Forty patients were randomized to receive 0.75 μg · kg^?1 fentanyl and a M or P bolus followed by an infusion; (M I5 μg · kg^?1 + 0.5 μg · kg^?1 · min^?1: P 0.5 mg · kg^?1 + 25 μg · kg^?1 min^?1). The incidences of complications and untoward events requinng intervention were documented. These included respiratory depression, excessive pain, inappropriate movements and the inability to examine the patient. The satisfaction of the anaesthetic technique from the perspective of both the neuroradiologist and the patient was scored.

Results

The incidence and types of complications were not different between the two groups. Pain occurred in 12 patients (6M, 6P), inappropriate movements in 17 (7M, 10P) and respiratory changes in 10 patients (2M, 8P).

Conclusions

Both techniques were satisfactory and the incidence of complications was similar for both groups.     

Intravenous ketorolac vs diclofenac for analgesia after maxillofacial surgery

Purpose

To compare the efficacy of the nonsteroidal antiinflammatory drugs (NSAID), ketorolac and diclofenac in prevention of pain after maxillofacial surgery.

Methods

Sixty ASA I– II patients (30 in each group) received randomly, and double blindly either ketorolac 0.4 mg · kg^{? 1} or diclofenac 1.0 mg · kg^{? 1} iv after general anaesthesia induction, before surgical incision. In the ketorolac group, the same dose was repeated iv three times at six hour intervals. The diclofenac group patients received diclofenac 1.0 mg μ kg^{? 1} after 12 hr iv. Rescue analgesic medication consisting of oxycodone 0.03 mg · kg^{? 1} iv, was administered by a patient controlled analgesia apparatus.

Results

Two patients in the ketorolac and three patients in the diclofenac group did not need oxycodone during the study period. On average, 12 and 11 doses of oxycodone were needed in the ketorolac and the diclofenac groups, respectively (NS). Sideeffects were similar in both groups. All patients except one were satisfied with the pain therapy.

Conclusion

Parenteral ketorolac (0.4 mg · kg^{? 1} four times in 24 hr) and diclofenac (1 mg · kg^{? 1} twice in 24 hr) were similar, but insufficient alone, for analgesia after maxillofacial surgery.     

Lower oesophageal sphincter tone increases after induction of anaesthesia in pigs with full stomach

Purpose

The lower oesophageal sphincter (LOS) is the main mechanism that prevents gastro-oesophageal regurgitation during anaesthesia. The aim of this study was to assess the effect on lower oesophageal sphincter pressure (LOSP) of rapid sequence induction in pigs with full stomachs.

Methods

Lower oesophageal sphincter pressure and oesophageal barrier pressure (BrP = LOSP minus gastric pressure) were measured using a water-perfused manometric catheter method in 12 pigs after gastric filling with 500 ml of liquid nutrient mixture. Six pigs were randomly allocated to receive 5 mg · kg^?1 propofol and 3 mg · kg^?1 succinylcholineiv, and six pigs received 8 mg · kg^?1 thiopentone and 3 mg · kg^?1 succinylcholineiv.

Results

After induction, mean LOSP increased during the period with fasciculations from 19 ± 4 mmHg to 28 ± 5 mmHg in the propofol-succinylcholine group and from 23 ± 6 mmHg to 36 ± 7 mmHg in the thiopentone-succinylcholine group. The LOSP remained elevated after the fasciculations. LOSP and BrP were not different between the groups.

Conclusions

Induction of anaesthesia with propofol-succinylcholine or thiopentone-succinylcholine increases LOSP and, consequently, BrP in pigs with a full stomach. This increase begins before fasciculations and remains elevated for the period when intubation would occur.     

Volume kinetics of Ringer’s solution and dextran 3% during induction of spinal anaesthesia for Caesarean section

Purpose

To study how the body handles fluid given intravenously during the onset of spinal anaesthesia in women scheduled for Caesarean section.

Methods

The effect of spinal anaesthesia on the volume kinetics of a constant-rate infusion of 25 ml · kg^?1 of Ringer’s solution (n = 11) and 10 ml · kg^?1 of dextran 3% 60 (n = 8) was studied before elective Caesarean section, Measurements of the blood haemoglobin concentration and urine excretion served as input variables in calculations of the size(s) of the body fluid spaces expanded by the infused fluid. The blood glucose level was also monitored.

Results

When a one-volume kinetic model were fitted to the data, spinal anaesthesia reduced the size of the expanded body fluid space by 30% (Ringer’s) and 58% (dextran) (P < 0.02) When a two-volume model was statistically justified, anaesthesia reduced the rate of fluid equilibration between the two expanded body fluid spaces by 47% and 19%, respectively (P < 0.04) The baseline volume for the primary (central) fluid space was smaller than the expected plasma volume; 1.5 l for Ringer’s solution and 0.9 l for dextran. Only small changes in the blood glucose concentration were found.

Conclusion

The onset of spinal anaesthesia induces acute changes in the body’s handling of infused fluid that can be described by volume kinetic analysis.     

Epidural and intravenous bolus morphine for postoperative analgesia in infants

Purpose

To compare two doses of bolus epidural morphine with bolus iv morphine for postoperative pain after abdominal or genitourinary surgery in infants.

Methods

Eighteen infants were randomly assigned to bolus epidural morphine (0.025 mg · kg^?1 or 0.050 mg · kg^?1) or bolus iv morphine (0.050–0.150 mg · kg^?1). Postoperative pain was assessed and analgesia provided, using a modified infant pain scale. Monitoring included continuous ECG, pulse oximetry, impedance and nasal thermistor pneumography. The CO₂ response curves and serum morphine concentrations were measured postoperatively.

Results

Postoperative analgesia was provided within five minutes by all treatment methods. Epidural groups required fewer morphine doses (3.8 ± 0.8 for low dose [LE], 3.5 ± 0.8 for high dose epidural [HE] vs. 6.7 ± 1.6 for iv, P < 0.05) and less total morphine (0.11 ± 0.04 mg · kg^?1 for LE, 0.16 ± 0.04 for HE vs 0.67 ± 0.34 for iv, P < 0.05) on POD1 Dose changes were necessary in all groups for satisfactory pain scores. Pruritus, apnoea, and haemoglobin desaturation occurred in all groups. CO₂ response curve slopes, similar preoperatively (range 36–41 ml · min^?1 · mmHg ETco ₂ ^?1 · kg^?1) were generally depressed (range, 16–27 ml · min^?1 · mmHg ETco ₂ ^?1 · kg^?1) on POD1. Serum morphine concentrations, negligible in LE (<2 ng · ml^?1), were similar in the HE and iv groups (peak 8.5 ± 12.5 and 8.6 ± 2.4 ng · ml^?1, respectively).

Conclusion

Epidural and iv morphine provide infants effective postoperative analgesia, although side effects are common. Epidural morphine gives satisfactory analgesia with fewer doses (less total morphine); epidural morphine 0.025 mg · kg^?1 is appropriate initially. Infants receiving epidural or iv morphine analgesia postoperatively need close observation in hospital with continuous pulse oximetry.     

Analgesia after otoplasty: regional nerve blockade vs local anaesthetic infiltration of the ear

Purpose

Children scheduled to undergo otoplasty experience severe pain postoperatively. Nausea and vomiting is also a problem. This study was designed to compare two analgesic techniques (i) regional nerve blockade (ii) local anaesthetic infiltration, with respect to quality and duration of analgesia, opioid requirements and the incidence of postoperative nausea and vomiting (PONV).

Methods

Forty three children, ASA I–II, aged 3–15 yr, were studied and followed for 24 hr postoperatively. Patients were randomised into two groups. Patients in Group A received local infiltration with lidocaine 1% with adrenaline 1:200,000 0.4 ml·kg^?1 (n = 21). Patients in Group B (n = 22) received nerve blockade, bupivacaine 0.5%, 0.4 ml·kg^?1. No other form of analgesia was used intraoperatively. Quality and duration of analgesia were assessed using pain and sedation scores recorded by a blinded observer at 0, 5, 10, 15, 30, 45 min with Recovery Room, and at 0, 30, 60, 90, 120, 180, 240, 360, 480 min on the ward. Pain score > 6 was treated with fentanyl 1 μg·kg^?1 iv (recovery) and morphine 0.2 mg·kg^?1 im or mefenamic acid 8 mg · kg^?1 po on the ward. Time to first supple-mental analgesia was noted. Mean duration of analgesia was 8.6 (1,1–24) hr, Group A and 10.5 (1,3–24) hr, Group B (P > 0.7). 24% per cent of children (Group A) and 27% (Group B) required no supplemental analgesia (P > 0.6). The degree of pain control resulted in a low requirement for opioids, Group A: 24%, Group B: 14% (P:NS). The overall incidence of PONV was 43% (Group A) and 36% (Group B) (P:NS): PONV correlated with opioid use. There were no differences between the groups with regard to pain/sedation scores, quality/duration of analgesia, opioid requirements and incidence of PONV.

Conclusion

Both techniques provided excellent postoperative analgesia. Lidocaine 1% infiltration (adrenaline 1:200,000) has the added advantage of improving surgical field and haemostasis. Thus, we advocate use of the simpler technique.     

Latex anaphylaxis during tissue expander insertion in a healthy child

Purpose

To report intraoperative latex anaphylaxis that occurred in an otherwise healthy child. Although latex anaphylaxis is seen in patients with myelodysplasia, genitourinary anomalies, sensitised healthcare workers, and patients with frequent exposure to latex, it has not been described in otherwise healthy children.

Clinical features

A nine-year-old girl developed intraoperative latex anaphylaxis manifested by increased airway pressure, expiratory wheezing, a decrease in oxygen saturation, severe hypotension and urticaria. The patient was treated with 5 μg·kg^?1 epinephrine iv and 5 mg·kg^?1 hydrocortisone iv. She required an epinephrine infusion of 0.4 μg·kg^?1 ·min^?1 and prolonged ICU admission. Her only previous latex exposure was during plastic surgical procedures. Latex allergy was confirmed weeks later using the prick method allergy testing.

Conclusion

Latex anaphylaxis can occur in otherwise healthy children whose only latex exposure occurred during a previous operation, including plastic surgery.     

Perioperative pulmonary aspiration in children: a review

The incidence of significant pulmonary aspiration in children is very low. Factors determining risk include the anaesthetist's experience, the child's ASA status, gastro-oesophageal disease, obesity, intra-abdominal obstruction, emergencies, trauma and the occurrence of laryngospasm. The diagnosis of pulmonary aspiration may be confused with post-obstructive pulmonary oedema. Several approaches to risk reduction can be used and include appropriate pre-operative fasting, acid aspiration prophylaxis and anaesthetic management. The widespread use of acid aspiration prophylaxis cannot be justified. Less emphasis should be placed on the ‘cut-off’ values for gastric fluid contents of pH 2.5 and volume 0.4 ml·kg^?1 in defining aspiration risk. Clear fluid fasts beyond 2–3 h do not result in reduced gastric fluid volume and if prolonged can be potentially harmful. It seems appropriate to use this interval in fasting guidelines for clear fluids. Recommended guidelines for solids vary from 4 h to no solids on the day of surgery.     

Dose-response to anaesthetic induction with sufentanil: haemodynamic and electroencephalographic effects

Purpose

To determine the effect of a five-fold variation in sufentanil dose on the haemodynamic and electroencephalo graphic (EEG) response to anaesthetic induction and tracheal intubation.

Methods

Thirty-four patients undergoing elective coronary artery bypass grafting (CABG) participated in this randomized double-blind study. Patients in Group L (n= 17) received 3 μg · kg^?1 sufentanil and those in Group H (n= 17) 15 μg · kg^?1. Premedication was 60 μg · kg^?1 lorazepam po. Anaesthesia and neuromuscular blockade were induced by infusing sufentanil and 0.15 mg · kg^?1 vecuronium iv over five minutes. Haemodynamic data and the electroencephalographic (EEG) spectral edge were acquired by computer and compared at Control, Induction and Intubation.

Results

Sufentanil dose did not affect the haemodynamic or EEG response at end-induction. No bradyarrhythmias occurred, and the incidence of hypotension was 12% in both groups. However, during induction apparent electromyographic artifacts and a transiently greater increase in heart rate were observed in Group H. The serum sufentanil concentration at Induction was 6.1 ± 1.8 ng · ml^?1 in Group L and 25.4 ± 8.8 ng · ml^?1 in Group H, and did not correlate with haemodynamic changes. No patient recalled any intraoperative event.

Conclusion

Increasing sufentanil dose from 3 to 15 μg · kg^?1 does not influence the ultimate haemodynamic response to induction. Combined with lorazepam premedication, 3 μg · kg^?1 sufentanil produces near-maximal haemodynamic and EEG effects and is adequate for induction and tracheal intubation of patients undergoing CABG. Sufentanil 15 μg · kg^?1 is no more efficacious, and causes transient cardiovascular stimulation.