High-flow nasal oxygen for children's airway surgery to reduce hypoxaemic events: a randomised controlled trial.

BACKGROUND: Tubeless upper airway surgery in children is a complex procedure in which surgeons and anaesthetists share the same operating field. These procedures are often interrupted for rescue oxygen therapy. The efficacy of nasal high-flow oxygen to decrease the frequency of rescue interruptions in children undergoing upper airway surgery is unknown. METHODS: In this multicentre randomised trial conducted in five tertiary hospitals in Australia, children aged 0-16 years who required tubeless upper airway surgery were randomised (1:1) by a web-based randomisation tool to either nasal high-flow oxygen delivery or standard oxygen therapy (oxygen flows of up to 6 L/min). Randomisation was stratified by site and age (<1 year, 1-4 years, and 5-16 years). Subsequent tubeless upper airway surgery procedures in the same child could be included if there were more than 2 weeks between the procedures, and repeat surgical procedures meeting this condition were considered to be independent events. The oxygen therapy could not be masked, but the investigators remained blinded until outcome data were locked. The primary outcome was successful anaesthesia without interruption of the surgical procedure for rescue oxygenation. A rescue oxygenation event was defined as an interruption of the surgical procedure to deliver positive pressure ventilation using either bag mask technique, insertion of an endotracheal tube, or laryngeal mask to improve oxygenation. There were ten secondary outcomes, including the proportion of procedures with a hypoxaemic event (SpO2 <90%). Analyses were done on an intention-to-treat (ITT) basis. Safety was assessed in all enrolled participants. This trial is registered in the Australian New Zealand Clinical Trials Registry, ACTRN12618000949280, and is completed. FINDINGS: From Sept 4, 2018, to April 12, 2021, 581 procedures in 487 children were randomly assigned to high-flow oxygen (297 procedures) or standard care (284 procedures); after exclusions, 528 procedures (267 assigned to high-flow oxygen and 261 assigned to standard care) in 483 children (293 male and 190 female) were included in the ITT analysis. The primary outcome of successful anaesthesia without interruption for tubeless airway surgery was achieved in 236 (88%) of 267 procedures on high-flow oxygen and in 229 (88%) of 261 procedures on standard care (adjusted risk ratio [RR] 1·02, 95% CI 0·96-1·08, p=0·82). There were 51 (19%) procedures with a hypoxaemic event in the high-flow oxygen group and 57 (22%) in the standard care group (RR 0·86, 95% CI 0·58-1·24). Of the other prespecified secondary outcomes, none showed a significant difference between groups. Adverse events of epistaxis, laryngospasm, bronchospasm, hypoxaemia, bradycardia, cardiac arrest, hypotension, or death were similar in both study groups. INTERPRETATION: Nasal high-flow oxygen during tubeless upper airway surgery did not reduce the proportion of interruptions of the procedures for rescue oxygenation compared with standard care. There were no differences in adverse events between the intervention groups. These results suggest that both approaches, nasal high-flow or standard oxygen, are suitable alternatives to maintain oxygenation in children undergoing upper airway surgery. FUNDING: Thrasher Research Fund, the Australian and New Zealand College of Anaesthetists, the Society for Paediatric Anaesthesia in New Zealand and Australia.

Prediction of Early Postoperative Pain in Infants Undergoing Primary Cleft Palate Repair.

OBJECTIVE: Identification of at risk patients before surgery could facilitate improved clinical communication, care pathways and postoperative pain management. DESIGN: A retrospective cohort study was performed in all infants who had undergone cleft palate repair. SETTING: Tertiary Institutional. PARTICIPANTS: Infants < 36 months of age who underwent primary repair of cleft palate between March 2016 and July 2022. INTERVENTION: Requirement for analgesic intervention in the post operative care unit. MAIN OUTCOME MEASURE: Adverse perioperative event defined as pain or distress. Secondary outcomes were the incidence of airway obstruction, hypoxemia or unplanned intensive care admission. RESULTS: Two hundred and ninety one patients (14.6 months,10.1 kg weight) were included. Cleft distribution included submucous (5.2%), Veau I (23.4%), Veau 2 (38.1%), Veau 3 (24.4%), and Veau 4 (8.9%). Overall 35% of 291 infants undergoing cleft palate repair experienced pain or distress requiring opiate intervention in the first hour after surgery. Infants with a Veau 4 cleft palate had 1.8 times and Veau 2 cleft palate had 1.5 times the risk of postoperative pain compared to infants with Veau 1 cleft palate (relative risk 1.82, 95%CI 1.04-3.18 and 1.49, 95%CI 0.96-2.32 respectively). The use of bilateral above elbow arm splints was significantly associated with postoperative pain or distress (odds ratio 2.23, 95%CI 1.01-5.16). CONCLUSIONS: Post operative pain requiring intervention in PACU is common despite adequate intraoperative multimodal analgesia, local anaesthesia infiltration and postoperative opiate infusions. Infants undergoing soft palate alone or submucous palate repair may require less perioperative opiates.

High-flow oxygen for children's airway surgery: randomised controlled trial protocol (HAMSTER).

INTRODUCTION: Hypoxaemia during anaesthesia for tubeless upper airway surgery in children with abnormal airways is common due to the complexity of balancing adequate depth of anaesthesia with maintenance of spontaneous breathing and providing an uninterrupted field of view of the upper airway for the surgeon. High-flow nasal oxygenation (HIGH-FLOW) can prolong safe apnoea time and be used in children with abnormal airways but to date has not been compared with the alternative technique of low-flow nasal oxygenation (LOW-FLOW). The aim is to investigate if use of HIGH-FLOW can reduce the number of hypoxaemic events requiring rescue oxygenation compared with LOW-FLOW. METHODS AND ANALYSIS: High-flow oxygen for children's airway surgery: randomised controlled trial (HAMSTER) is a multicentre, unmasked, randomised controlled, parallel group, superiority trial comparing two oxygenation techniques during anaesthesia. Children (n=530) aged >37 weeks to 16 years presenting for elective tubeless upper airway surgery who fulfil inclusion but not exclusion criteria will be randomised prior to surgery to HIGH-FLOW or LOW-FLOW post induction of anaesthesia. Maintenance of anaesthesia with HIGH-FLOW requires Total IntraVenous Anaesthesia (TIVA) and with LOW-FLOW, either inhalational or TIVA at discretion of anaesthetist. The primary outcome is the incidence of hypoxaemic events requiring interruption of procedure for rescue oxygenation by positive pressure ventilation and the secondary outcome includes total hypoxaemia time, adverse cardiorespiratory events and unexpected paediatric intensive care admission admission. Hypoxaemia is defined as Sp02 <90%. Analysis will be conducted on an intention-to-treat basis. ETHICS AND DISSEMINATION: Ethical approval has been obtained by Children's Health Queensland Human Research Ethics Committee (HREC/18/QRCH/130). The trial commenced recruitment in 2018. The primary manuscript will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: The HAMSTER is registered with the Australia and New Zealand Clinical TrialsRegistry: ACTRN12618000949280.

Pharmacokinetics of levobupivacaine following infant spinal anesthesia.

BACKGROUND: Infant spinal anesthesia with levobupivacaine has been promoted as a technique to reduce both the risk of postoperative apnea and exposure to volatile anesthesia. There is, however, no pharmacokinetic data to support the currently recommended doses. AIMS: Our aim was to determine whether infant levobupivacaine spinal anesthesia is associated with plasma concentrations consistent with a low risk of local anesthetic systemic toxicity. METHODS: This was an open-label pharmacokinetic safety and tolerability study of levobupivacaine spinal anesthesia in infants <55 weeks Post Menstrual Age undergoing lower abdominal surgery. Infants received a spinal anesthetic with levobupivacaine 1 mg·kg(-1) in the left lateral position. RESULTS: Spinal anesthesia was successful in 25 (86.2%) of 29 infants (postmenstrual age 36-52 weeks; weight 2.2-4.7 kg). The median (IQR) total venous levobupivacaine plasma concentrations was 0.33 (0.25-0.42) µg·ml(-1) and unbound venous levobupivacaine was 19.5 (14.5-38) ng·ml(-1) . Median protein binding was 93.5 (91.4-96%). Alpha-1 acid glycoprotein concentrations were 0.25 (0.17-0.37) g·l(-1) and albumin concentrations were 29 (24-32) g·l(-1) . CONCLUSION: Total plasma concentrations and unbound (free) concentration of levobupivacaine were consistently lower than concentrations reported in cases of pediatric local anesthetic toxicity. In a small number of infants requiring a repeat spinal of 1 mg·kg(-1) was also associated with acceptable total and free concentrations. We conclude that levobupivacaine at 1 mg·kg(-1) is associated with no systemic side effects in infants receiving awake spinal anesthesia.