Journal Watch Search

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218 Articles Found

Perioperative management of the child with asthma.

January 17, 2023

This educational review outlines the pathophysiology of asthma, key aspects of preoperative evaluation of children with asthma, and provides updates in asthma treatment from multinational guidelines, including recommendations for the treatment of bronchospasm under anaesthesia.

This review focuses on the ‘Th2’ or ‘atopic, aspirin exacerbated respiratory disease’ (AERD) endotype, as it is by far the most common in paediatric asthma, where sensitisation to aeroallergens results in CD4 activation and release of interleukins IL4, IL5 and IL13.

Preoperative evaluation:

Spirometry and peak expiratory flow rate (PEFR) cannot be reliably performed in children under 5 years, therefore history and examination findings may be more pragmatic in the perioperative setting.

Risk factors for perioperative respiratory adverse events (PRAEs) include age <5yrs, moderate to severe asthma, respiratory tract infection within last 4 weeks, previous exacerbations under GA, need for intubation and ventilation for an exacerbation. Anaesthetic/surgical risk factors include intubation (vs supraglottic airway or bag mask ventilation only), airway surgery, and prolonged operation. Additional components of preoperative evaluation should include frequency of symptoms, exercise limitation, frequency of short acting beta agonists or ‘reliever’ medication use, known triggers, recent exacerbations, and level of care required if hospitalised. The child should be examined for wheeze, increased work of breathing, and abnormal vital signs.

Stratification based on severity is recommended:

  • Well controlled asthma (no need for reliever medication for last month, no exercise limitation, and symptom free): can proceed as a day case at a general or regional hospital
  • Mild asthma (symptoms less than three times per week, and no limitation in activity): can proceed with elective cases as a day case at a general or regional hospital.
  • Moderate asthma (daily or nightly symptoms, may have exercise limitation). Weighing risks vs benefits of elective surgery can be difficult. If the child is well, with a recent review by treating physician, and compliant with treatment, it is safe to proceed with elective cases.
  • Severe asthma (persistent daily or nightly symptoms, requires high dose inhaled corticosteroids plus a second agent to achieve symptom control, or is uncontrolled despite therapy). Recommend review by respiratory physician to optimise control and plan for perioperative care, consider performing surgery in a centre with paediatric HDU or PICU facility.

Perioperative management recommendations:

  • Ensure treatment compliance in the preceding month.
  • Children on > 15mg/m2 hydrocortisone equivalent for more than 1 month, are at risk of adrenal suppression, and perioperative steroid replacement should be considered.
  • Administer short acting inhaled beta agonist via spacer or nebuliser preoperatively
  • Ensure adequate depth of anaesthesia before instrumenting airway or painful stimuli
  • Consider sevoflurane and ketamine use to promote bronchodilation (as well as magnesium)
  • Consider choice of airway & bronchospasm risk: LMA < ETT
  • Minimise histamine releasing drugs (e.g., synthetic opioids over morphine)

Management of severe bronchospasm under general anaesthesia

  • Pharmacological agents:
    • First line: inhaled salbutamol via anaesthetic circuit
    • Deepen anaesthesia and consider changing to volatile if maintaining with TIVA
    • Second line: nebulised ipratropium, IV magnesium, IV salbutamol, hydrocortisone, and in extremis, IV adrenaline
    • Consider commencing infusions of salbutamol, aminophylline, adrenaline or ketamine
  • Ventilation strategies are listed as suggestions without an in-depth discussion of supporting literature
    • Target oxygen saturation >90%, allow permissive hypercapnia with pH >7.2
    • Maintain full paralysis
    • Either pressure or volume control modes can be utilised- the authors recommend a mode that is most familiar to the treating clinician
    • Tidal volumes of 5-7 ml/kg
    • Target plateau pressure <30 cmH20, and PIP of <40 mmHg to avoid barotrauma
    • Consider low PEEP of 4-5 cmH2O
    • Increase expiratory time aiming I:E ratio 1:3-1:4
    • Monitor for breath stacking: ensure flow reaches baseline at end expiration, and that end tidal CO2 reaches a plateau
    • Refrain from manually decompressing the chest: can precipitate cardiac arrest

In summary, this review paper provides a refresher for clinicians in the risk stratification and perioperative management of children with asthma, based on international guidelines formed from available evidence and consensus expert opinion.

 

Reviewed by Dr Heather Patterson

Bilateral erector spinae plane blocks in children undergoing cardiac surgery: A randomized, controlled study.

January 17, 2023

This small, randomized control study of 40 patients investigated the utility of erector spinae plane blocks (ESPB) in paediatric sternotomy for cardiac procedures. The primary outcome was cumulative morphine consumption in the first 24 hours post-operatively. Secondary outcomes included pain & sedation, time to extubation and ICU length of stay.

The mean age of patients presenting for cardiac surgery was 6 years (range 2 – 10 years), with procedures limited to ASD or VSD closures & aortic membrane excision. Notably the duration of surgery was significantly longer in the ESPB group, and this group also received 2 microg/kg more fentanyl than the control group despite an apparent set timing and dose protocol for the administration of Fentanyl intra-op. This was not significant, but no explanation was offered in the paper either.

 

Strengths and weaknesses

Strengths of the study included that there were only 2 people experienced with performing ESPB doing the blocks in a standardized manner. The assessor measuring pain scores in the first 24 hours was blinded. Blocks were performed at a standardized period in the perioperative journey (prior to surgery & after induction of anaesthesia).

Weakness of the study were the small number of patients included and no explanation as to why 2 patients were excluded. There was no assessment of dermatomes in any patient postoperatively, and despite following up patients until discharge, assessment of morphine consumption stopped at 24 hours.

 

Results

As a primary outcome, the authors demonstrated a significant reduction (p=0.043) in rescue morphine (mg/kg) dosing, administered as 0.05 mg/kg boluses to a MOPS score of >4, in the first 24 hours post-operatively. The was no difference in any of the secondary outcomes listed above.

 

Discussion

The authors acknowledge that this is a small study and suggest that further larger trials are required to determine whether the block is effective in reducing pain scores and opioid consumption post-operatively following cardiac surgery in paediatric patients. One of the arguments the authors list for performing the ESPB is as part of an ERAS program to reduce PONV because of reduced opioid consumption. There was no difference in rates of PONV between the groups, a point acknowledged by the authors, but perhaps the difference in opioid consumption, although statistically significant, fails to make a clinical difference as demonstrated by no reduction in any of the secondary clinical outcomes or PONV. The discussion also highlights that there have been both positive and negative trials previously published in the area of plane blocks performed for sternotomy procedures.

 

Reviewed by Dr Neil Hauser

Scheduled methadone reduces overall opioid requirements after pediatric posterior spinal fusion: A single center retrospective case series

January 17, 2023

What?

  • A retrospective chart review of 94 patients undergoing posterior spinal fusion for adolescent idiopathic scoliosis between 2015 and 2020 at the American Family Children’s Hospital, University of Wisconsin, USA.
  • Three patient groups:
    • Group PCA received a hydromorphone PCA without methadone
    • Group PCA + Methadone received pre-incisional methadone and a hydromorphone PCA
    • Group Methadone received pre-incisional methadone, scheduled postoperative methadone, and no PCA
  • Methadone dosing:
    • Pre-incisional methadone 0.2 mg/kg (max 20 mg)
    • Post-operative methadone 0.1mg/kg (max 5 mg) IV in the PACU at first request for analgesia, and methadone 0.1 mg/kg (max 5 mg) IV 6 h after the PACU dose, with backup rescue hydromorphone IV boluses available on request.
  • The primary outcome was postoperative opioid use over 72hrs. Secondary outcomes included pain scores, sedation scores and length of stay.
  • Intraoperatively all patients received TIVA with remifentanil or fentanyl infusion and additional opioid boluses at the anaesthetist’s discretion.
  • The study period included post-operative days 0-3.

 

Findings

  • Group Methadone used significantly less opioid than Group PCA and Group PCA + Methadone
    • Mean hydromorphone equivalents in mg/kg = 0.18 vs 0.33 and 0.30 respectively
  • There were no statistically significant differences between the groups for secondary outcomes.

 

Comments

Intravenous methadone is a unique opioid that acts at multiple receptors, including mu-opioid, kappa- opioid, N- Methyl- D- aspartate (NMDA), serotonin, and norepinephrine. The clinical duration of action is dose-dependent and is significantly extended with repeat dosing. Methadone undergoes rapid redistribution after bolus administration and so supplementation of the pre-incisional dose with subsequent doses maintains analgesic plasma levels. Dose finding studies have found similar pharmacokinetics in adolescents and adults.

 

There was generally standardisation of care for spinal fusion patients with a streamlined multidisciplinary care pathway developed in 2015, which limits other confounding factors in post-operative care. All patients received standardised non opioid analgesia including gabapentin, acetaminophen and non-steroidal anti-inflammatories.

 

In terms of safety profile, none of the patients in the methadone groups experienced QT prolongation while on telemetry for the first 24 hrs post operatively.

 

This is a single centre retrospective chart review, so it is prone to bias and the numbers of patients in each group is small, with unequal patient sizes, and missing pain data points in all groups.

 

Total opioid was calculated incorporating methadone, hydromorphone, oxycodone and morphine doses and excluded short acting opioid doses of fentanyl, remifentanil, alfentanil and sufentanil.

There was a statistically significant difference in long-acting opioid use between all groups, however there was not a clinically significant difference between the PCA group and PCA + methadone group. This review suggests that the real opioid sparing benefit was gained by the scheduled methadone group receiving multiple doses of methadone.

 

Reviewed by Dr Bojana Stepanovic