Differences in Blood Pressure in Infants After General Anesthesia Compared to Awake Regional Anesthesia (GAS Study-A Prospective Randomized Trial).

BACKGROUND: The General Anesthesia compared to Spinal anesthesia (GAS) study is a prospective randomized, controlled, multisite, trial designed to assess the influence of general anesthesia (GA) on neurodevelopment at 5 years of age. A secondary aim obtained from the blood pressure data of the GAS trial is to compare rates of intraoperative hypotension after anesthesia and to identify risk factors for intraoperative hypotension. METHODS: A total of 722 infants ≤60 weeks postmenstrual age undergoing inguinal herniorrhaphy were randomized to either bupivacaine regional anesthesia (RA) or sevoflurane GA. Exclusion criteria included risk factors for adverse neurodevelopmental outcome and infants born at <26 weeks of gestation. Moderate hypotension was defined as mean arterial pressure measurement of <35 mm Hg. Any hypotension was defined as mean arterial pressure of <45 mm Hg. Epochs were defined as 5-minute measurement periods. The primary outcome was any measured hypotension <35 mm Hg from start of anesthesia to leaving the operating room. This analysis is reported primarily as intention to treat (ITT) and secondarily as per protocol. RESULTS: The relative risk of GA compared with RA predicting any measured hypotension of <35 mm Hg from the start of anesthesia to leaving the operating room was 2.8 (confidence interval [CI], 2.0-4.1; P < .001) by ITT analysis and 4.5 (CI, 2.7-7.4, P < .001) as per protocol analysis. In the GA group, 87% and 49%, and in the RA group, 41% and 16%, exhibited any or moderate hypotension by ITT, respectively. In multivariable modeling, group assignment (GA versus RA), weight at the time of surgery, and minimal intraoperative temperature were risk factors for hypotension. Interventions for hypotension occurred more commonly in the GA group compared with the RA group (relative risk, 2.8, 95% CI, 1.7-4.4 by ITT). CONCLUSIONS: RA reduces the incidence of hypotension and the chance of intervention to treat it compared with sevoflurane anesthesia in young infants undergoing inguinal hernia repair.

Necrotising soft tissue infections: the effect of hyperbaric oxygen on mortality.

In a single-centre, retrospective, case-controlled study of patients attending the Alfred Hospital in Prahran, Victoria, we assessed the effect of hyperbaric oxygen therapy (HBOT) in reducing mortality or morbidity in patients with necrotising fasciitis (NF) over a 13-year period from 2002 to 2014. A total of three hundred and forty-one patients with NF were included in the study, of whom 275 received HBOT and 66 did not. The most commonly involved sites were the perineum (33.7%), lower limb (29.9%) and trunk (18.2%). The commonest predisposing factor was diabetes mellitus (34.8%). Polymicrobial NF (type 1 NF) occurred in 50.7% and Group A streptococcal fasciitis (type 2 NF) occurred in 25.8% of patients. Mortality was 14.4% overall, 12% in those treated with, and 24.3% in those not treated with, HBOT. ICU support was required in 248 (72.7%) patients. Independent factors impacting on mortality included HBOT (odds ratio [OR] 0.42 [0.22 to 0.83], P=0.01), increased age (OR 1.06 [1.03 to 1.08], P=0.001) and immunosuppression (OR 2.6 [1.23 to 5.51], P=0.01). Mortality was linked to illness severity at presentation, however when adjusted for severity score and need for intensive care management, HBOT was associated with significant reduction in mortality.

Australian paediatric hyperbaric oxygen therapy 1998-2011.

For a large number of ischaemic, infective, inflammatory or traumatic conditions, hyperbaric oxygen therapy is either the only treatment or an adjunct that significantly reduces morbidity and mortality. The primary aim of this review is to identify clinical conditions treated in a paediatric population referred to Australian hyperbaric units. Secondary aims are to describe outcomes of treatment and detail any complications occurring during treatment or during transfer between units. This was a retrospective cohort study (January 1998-December 2011) of children treated at four Australian hyperbaric medical units. A total of 112 children underwent 1099 hyperbaric treatments for 14 indications. Ages were not normally distributed with a median age of 14 years (interquartile range 11-16; range 0.25-16 years). Treatments were completed as planned in 81.5% of cases with 25 patients' treatment terminated at the request of physicians, parents or patients. Complications relating to hyperbaric oxygen therapy occurred in 58 treatments (5.3%). Central nervous system oxygen toxicity occurred in 1:366 treatments. Our findings indicate that provision of hyperbaric oxygen therapy to children is feasible in major regional hyperbaric units and is associated with low complication rates. Management of children in an adult hyperbaric facility, however, requires significant cooperation between paediatric, intensive care and hyperbaric consultants, as the need for transfer to another hospital and prolonged transports often impacts on optimal ongoing surgical and intensive care management.

Multidetector computed tomography (MDCT) for preoperative airway assessment in children with mucopolysaccharidoses.

BACKGROUND: Accumulation of glycosaminoglycans is known to cause significant problems in the anesthetic management of children with mucopolysaccharidoses (MPS). Clinical and standard radiological evaluation may convey insufficient information about the upper airway and trachea in children with MPS. Multidetector computed tomography (MDCT) images have been used to define the central airway and previous studies have recommended this tool to assess the airway of children who are considered at risk of difficult intubation. However, MDCT has not been recommended in MPS children. The aim of this clinical scenario study was to verify whether information from MDCT reconstruction of the airway is useful in airway management planning of children with MPS. METHODS: In a two phase questionnaire-based study, 26 pediatric anesthesiologists were asked to produce airway management plans for 5 children with MPS. An initial plan for airway control was reported after assessment of standard preoperative anesthetic charts. A subsequent airway strategy was then described after reviewing tracheal MDCT images of each patient. RESULTS: MDCT images provided additional clinically-relevant information in 87% (95% CI: 79-92%) of the evaluations. Reduction of tracheal size was the most common finding provided by the MDCT images. After reviewing the MDCT images, anesthesiologists changed their primary airway device selection in 21% of the evaluations (P=0.01). CONCLUSION: Airway reconstruction using MDCT images from a previous CT scan may provide a useful assessment tool for preoperative airway evaluation and planning in MPS children.

Relative potencies of bupivacaine, levobupivacaine, and ropivacaine for neonatal spinal anaesthesia.

BACKGROUND: Comparing the relative potency of new local anaesthetics such as levobupivacaine and ropivacaine with bupivacaine by the minimum local analgesic concentration model has not been described for neonatal spinal anaesthesia. This information is important to compare agents and to determine the most effective spinal dose. METHODS: We performed a two-stage study to determine the ED50, the ED95, and the relative analgesic potency of isobaric spinal bupivacaine, levobupivacaine, and ropivacaine in infants. In phase 1, 81 infants were randomized in a Dixon-Massey study to describe the minimum local analgesic dose. In phase 2, a further 70 patients were randomly allocated to receive spinal anaesthesia with doses in the upper dose-response range to define the ED95. RESULTS: The ED50 doses for bupivacaine, levobupivacaine, and ropivacaine were estimated by isotonic regression to be 0.30 mg kg(-1) [95% confidence interval (CI) 0.25-0.43], 0.55 mg kg(-1) (0.50-0.64), and 0.50 mg kg(-1) (0.43-0.64), respectively. The ED(95), respectively, of bupivacaine, levobupivacaine, and ropivacaine were 0.96 mg kg(-1) (95% CI 0.83-0.98), 1.18 mg kg(-1) (1.05-1.22), and 0.99 mg kg(-1) (0.73-1.50). The relative potency ratios at the ED(50) were bupivacaine:levobupivacaine 0.55 (95% CI 0.39-0.88), bupivacaine:ropivacaine 0.61 (0.41-1.00), and levobupivacaine:ropivacaine 1.09 (0.84-1.45). CONCLUSIONS: Appropriate doses for infant spinal anaesthesia are 1 mg kg(-1) of isobaric 0.5% bupivacaine and ropivacaine and 1.2 mg kg(-1) of isobaric 0.5% levobupivacaine.

Analgesic effectiveness of caudal levobupivacaine and ketamine.

BACKGROUND: Ketamine is used increasingly in paediatric anaesthetic practice to prolong the action of a caudal block. This study was designed to determine if adding S(+)-ketamine 0.5 mg kg(-1) allows a lower concentration of levobupivacaine to be used for caudal anaesthesia without loss of clinical effectiveness. METHODS: One hundred and sixty-four children (ASA I or II) aged 3 months-6 yr were randomly allocated to receive 1 ml kg(-1) of levobupivacaine 0.15% with 0.5 mg kg(-1) S(+)-ketamine (Group 1), levobupivacaine 0.175% with 0.5 mg kg(-1) S(+)-ketamine (Group 2), or levobupivacaine 0.2% (Group 3) by the caudal route. Pain, motor block, sedation, and requirement for postoperative analgesia were assessed up to 6 h after operation. RESULTS: There was no significant difference between the groups in effectiveness at first surgical incision. Significantly lower analgesic requirements were reported in Group 2 compared with Group 3 at wakeup, 180 and 360 min after operation. Time to first rescue analgesia was longer in Group 2 compared with Group 1 or 3. Kaplan-Meier survival analysis of analgesia free time demonstrated a significant advantage of Group 2 over Groups 1 and 3 (log rank P=0.05). The incidence of postoperative motor block was not significantly different between the groups. No excess sedation or dysphoric reactions were observed in the ketamine groups. CONCLUSIONS: The addition of 0.5 mg kg(-1) S(+)-ketamine to levobupivacaine 0.175% for caudal analgesia for lower abdominal and urological surgery is significantly more effective in providing postoperative analgesia than levobupivacaine 0.15% with 0.5 mg kg(-1) S(+)-ketamine or levobupivacaine 0.2%.

Preoperative hypnotherapy in the management of a child with anticipatory nausea and vomiting.

A six-year-old boy with oesophageal strictures secondary to neonatal repair of oesophageal atresia and requiring six to eight weekly oesophageal dilatations by bouginage developed anticipatory nausea and vomiting. This was effectively managed by a course of preoperative hypnotherapy over four sessions. Resolution of anticipatory nausea and vomiting occurred along with cessation of postoperative nausea and vomiting. This case supports early intervention with preoperative hypnotherapy in children with anticipatory nausea and vomiting that has not responded to other measures.

Bupivacaine caudal epidural anesthesia: assessing the effect of general anesthetic technique on block onset.

BACKGROUND: The primary objective of this prospective, randomized trial was to compare the effect of propofol and sevoflurane on effectiveness of regional anesthesia. As a secondary objective, we aimed at evaluating the influence of age on neuraxial block profile. METHODS: One hundred and thirteen healthy children aged <10 years, scheduled for general or urological surgical procedures were randomly allocated to receive either propofol or sevoflurane induction and maintenance. Children received caudal or lumbar epidural block depending on their weight and expected surgery. Time to onset of surgical anesthesia, intraoperative analgesic effectiveness, residual motor blockade, postoperative pain, and adverse effects were evaluated. To assess the influence of age on these measures children were further divided into three age groups: 0-24, 25-60 and >60 months. RESULTS: The mean time to onset of surgical anesthesia was significantly shorter in the sevoflurane group than the propofol group (3.1 vs 4.7 min, P < 0.01), independent of the type of regional technique employed. Distress on arousal in recovery was increased in children receiving sevoflurane (P = 0.03). There was no significant difference in residual motor blockade between the groups but children between 0 and 24 months receiving sevoflurane had a higher incidence of residual motor blockade 3 h after local anesthetic injection (P = 0.01). CONCLUSIONS: This study has demonstrated that general anesthesia with sevoflurane decreases the time to onset of surgical anesthesia relative to propofol anesthesia. This effect was most marked when sevoflurane anesthesia preceded caudal epidural blockade. The basis for this effect is most likely to be related to differential binding of the two anesthetic agents to receptors in the spinal cord that mediate immobility in response to surgical stimuli.

Comparison of thoracoscopic drainage with open thoracotomy for treatment of paediatric parapneumonic empyema.

The purpose of this study was to compare the efficacy of thoracoscopic drainage with open drainage of empyema in children. A retrospective case history audit was done of children presenting to a single major paediatric centre who underwent thoracoscopy drainage and decortication or open decortication and drainage (thoracotomy) between January 2000 and September 2002. Time to resolution of infection, duration of intercostal catheter (ICC) drainage, postoperative morphine requirements, and length of hospital admission were compared as primary measures of outcome. Thirty-three patients, 17 male and 16 female, aged between 1 month and 21 years were included in the study. Median age at surgery was 2.6 years. The location of the empyema was right-sided in 17 patients and left-sided in 16 patients. The empyema was drained by thoracoscopy in 11 patients, and 22 patients underwent thoracotomy. Two patients had thoracoscopy converted to thoracotomy for late-stage disease requiring greater surgical access. There were no differences between treatment groups with respect to duration of ICC drainage (p=0.6), duration of fever (p=0.6), length of stay (p=0.9), or postoperative morphine use (p=0.2). However, overall pain scores were lower in the thoracoscopy group, particularly on days 2 and 3; this approached statistical significance (p=0.07). This study has demonstrated that thoracoscopic drainage is an effective procedure for treating empyema in children. It is less invasive than open thoracotomy and is associated with less patient discomfort and less severe pain as measured by objective pain scores. We advocate thoracoscopic drainage for the majority of patients with empyema, except for those with advanced disease.

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.

Clinical course and medical management of neonates with severe cardiac failure related to vein of Galen malformation.

BACKGROUND: Neonatal presentation of vein of Galen aneurysmal malformations (VGAMs) with intractable cardiac failure is considered a poor prognostic sign. Interventional neuroradiology with embolisation has been shown to control cardiac failure, but there is a perception that neurological outcome in survivors is poor. OBJECTIVE: To determine if aggressive intensive care and anaesthetic management of cardiac failure before urgent embolisation can influence morbidity and mortality. PATIENTS: Nine newborns (four boys, five girls) were diagnosed with symptomatic vein of Galen malformations in the neonatal period during the period 1996-2001. Eight developed intractable high output cardiac failure requiring initial endovascular treatment in the first week of life. RESULTS: The immediate outcome after a series of endovascular procedures was control of cardiac failure and normal neurological function in six (66%) patients, one death from intractable cardiac failure in the neonatal period, and two late deaths with severe hypoxic-ischaemic neurological injury (33% mortality). Clinical review at 6 months to 4 years of age showed five infants with no evidence of neurological abnormality or cardiac failure and one child with mild developmental delay (11%). CONCLUSIONS: Aggressive medical treatment of cardiac failure and early neurointervention combined with modern neuroanaesthetic care results in good survival rates with low morbidity even in cases of high risk VGAM presenting in the immediate perinatal period with cardiac failure. Systemic arterial vasodilators improve outcome in neonates with cardiac failure secondary to VGAM. Excessive beta adrenergic stimulation induced by conventional inotropic agents may exacerbate systemic hypoperfusion.

Endovascular management of vein of Galen aneurysmal malformations presenting in the neonatal period.

BACKGROUND AND PURPOSE: Neonates with vein of Galen aneurysmal malformations (VGAMs) presenting with cardiac failure have high morbidity and mortality, and outcomes are significantly better in those presenting in later childhood. Neurologic outcomes in survivors are perceived to be uniformly poor, which may lead to the neonate being denied treatment. We assessed outcomes of modern neonatal intensive care and endovascular embolization in a consecutive series of such neonates presenting with cardiac failure. METHODS: Between 1996 and 1998, five infants (three male, two female) were diagnosed with symptomatic VGAMs in the first week of life, four of whom had intractable, high-output cardiac failure and underwent initial endovascular treatment. There were 15 endovascular procedures and one neurosurgical clipping in these five patients. Transarterial and transvenous routes were required, using multiple embolic agents. We emphasized the use of sonographically guided, percutaneous transtorcular-venous-access, moveable-core guidewire as an embolic agent; routine MR imaging; and MR angiography. RESULTS: Immediate outcomes included control of cardiac failure with normal neurologic function in four (80%) patients and one (20%) death from intractable cardiac failure. On follow-up examination, three (60%) infants showed no evidence of neurologic abnormality or cardiac failure; one (20%) infant showed moderate developmental delay. Two have had no further shunting on angiography, one has minimal flow, and one is awaiting follow-up imaging. CONCLUSION: Endovascular therapy with modern neuroanesthetic and neurointensive care can provide good outcomes even in the highest-risk neonates with VGAMs and cardiac failure. If medical management of cardiac failure fails, and there is no evidence of gross cerebral parenchymal damage on imaging, urgent endovascular treatment is feasible and can reduce the almost-100% mortality otherwise expected, without invariably severe morbidity. Use of multiple embolization strategies in multiple stages usually is necessary in these patients, and novel approaches and embolic agents may be necessary.

Plasma concentrations of bupivacaine after combined spinal epidural anaesthesia in infants and neonates.

The unbound and bound plasma concentration of bupivacaine in 50 infants less than 55 weeks postconceptual age was determined following combined spinal and epidural anaesthesia (csea). Plasma concentrations were determined at 15-min intervals up to 60 min postspinal anaesthesia. Maximum plasma bupivacaine levels were recorded between 45 and 60 min post CseA. Total plasma concentrations above a toxic threshold level of 4 microg.ml(-1) were recorded in 4% of patients and above 2.5 microg.ml(-1) in 10% of patients. Unbound bupivacaine levels were greater than a presumed toxic level of 0.25 microg.ml(-1) in 16% of cases and above 0.3 microg. ml(-1) in 14% of cases. A wide range of protein binding was measured (varying from 53.8-98.2%) and could not be correlated with standard indicators of local anaesthetic binding. Two neonates had brief apnoeas in the immediate perioperative phase but no adverse cardiac or central nervous system events attributable to the performance of Csea were demonstrated.

Laparotomy for necrotizing enterocolitis: intensive care nursery compared with operating theatre.

OBJECTIVE: To determine whether neonates requiring laparotomy for necrotizing enterocolitis (NEC) are more stable perioperatively and have less disruption of physiological parameters if surgery is performed in the neonatal intensive care unit (NICU) compared with the operating theatre (OR). METHODOLOGY: A retrospective case review was performed on 233 neonates referred for further surgical management of severe NEC in the period January 1989 to December 1997. Mortality and morbidity were compared by calculating the score for neonatal acute physiology (SNAP) and its attendant risk of mortality score. Thirty-six separate physiological variables were also compared pre- and postoperatively and the mean postoperative change was calculated. RESULTS: For neonates weighing less than 1500 g, mortality was linked to illness severity, as measured by SNAP, rather than operative location. Specific adverse events associated with secondary transfer to the OR included hypothermia, deterioration in oxygenation parameters, ventilation parameters and platelet count. The liberal use of blood products, albumin and bicarbonate in perioperative resuscitation may have obscured other effects. CONCLUSIONS: The use of the neonatal intensive care nursery for surgery on neonates weighing less than 1500 g with severe NEC can be justified and such use should be encouraged. In contrast, secondary transport of neonates weighing less than 1500 g to the OR for laparotomy is associated with significant deterioration in a number of physiological parameters, which may impact on morbidity.

Monitoring nitric oxide: a comparison of three monitors in a paediatric ventilator circuit.

Simultaneous measurements of nitric oxide (NO) (0-80 ppm) using a chemiluminescence monitor and two electrochemical monitors were performed during simulated paediatric mechanical ventilation. The mean difference (bias) between the chemiluminescence (Model 42H Thermo Environmental Instruments Inc) and an electrochemical monitor (Pulmonox Research and Development Corp) was 0.52 +/- 6.52 ppm (SD). The 95% confidence limits of the mean difference were 3.00 to -1.96 ppm and the limits of agreement between the two techniques were 13.56 to -12.52 ppm. The mean difference between the chemiluminescence monitor and another electrochemical monitor (NOxBox, Bedfont Scientific Inc) was -7.27 +/- 4.29 ppm. The 95% confidence limits of the mean difference were -9.02 to -5.56 ppm and limits of agreement of the two techniques were -16.13 to 1.55 ppm. These results suggest that electrochemical monitors may be used to guard against potentially toxic concentrations of NO (greater than 20 ppm). However they do not suggest that either of the electrochemical monitors may be used with confidence in lieu of the chemiluminescence monitor to regulate NO at low clinical NO levels (1-5 ppm).