Recent advances in paediatric anaesthesia

ABSTRACT

Recent development in science has led to a significant improvement in safety for the anaesthetic management of children. Enhanced recovery after surgery is one of the novel approaches aiming to enhance paediatric surgical outcomes and their quick recovery. Preoperative counselling, minimal fasting, and no routine pharmacological premedication are critical components of enhanced recovery after surgery. As anaesthetists, management of airway is our priority and introduction of paraoxygenation in addition to preoxygenation has resulted in reduction in desaturation episodes during periods of apnoea. Safe care has been made possible by improvements in monitoring, equipment, medications, techniques, and resuscitation protocols. We are motivated to collect more evidence regarding ongoing disputes and issues, such as the effect of anaesthesia on neurodevelopment.

INTRODUCTION

Over the past few decades, anaesthesiology has made tremendous improvements in patient safety, with a notable decrease in mortality. This improvement is mostly attributable to the advancement of science and the creation of novel theories, medications, procedures, and equipment. This narrative review aims to highlight the scientifically proven advances in the last 10 years in the field of paediatric anaesthesia. The intent of this narrative review is to discuss important recent paediatric anaesthesia developments.

PREOPERATIVE ANAESTHETIC MANAGEMENT

Due to enhanced recovery after surgery (ERAS), which is a protocolised approach with simultaneous application of numerous pre-existing principles seeking to improve the overall outcome for the patients, there have been many changes made to the preoperative care of a child. ERAS concentrates on all facets (preoperative, intraoperative, and postoperative care). Preadmission counselling and education are encouraged by ERAS recommendations, in particular providing parents with specific information regarding the type of surgery being performed, anaesthesia management, and the recovery schedule.[1] Recent international consensus has shifted from conservative long durations of fasting toward a more liberal policy of 1 hour for clear fluids and is endorsed by several national societies.[2] Gastric ultrasound has played a major role in establishing the safety for children while moving toward liberal feeding practices.[3] Hospitalisation and surgery can provoke significant stress and anxiety in children with adverse outcomes. As a routine, ERAS does not recommend pharmacological premedication for anxiolysis, especially with long-acting agents, but if the anxiety is significant, pharmacological intervention as anxiolysis is recommended. Nonpharmacological agents like preoperative anaesthesia visit and use of music and smart phones to allay anxiety have been found to be beneficial.

INTRAOPERATIVE MANAGEMENT

Preoxygenation increases the safety during apnoeic periods during intubation since children physiologically have low oxygen stores and high oxygen demands, but it is difficult to practically apply because of uncooperative nature of the children. Addition of apnoeic oxygenation as a strongly recommended step along with preoxygenation by many difficult airway recent guidelines has provided safe apnoea period of as long as 8 minutes in older children.[4]

ANAESTHESIA MONITORING

Traditionally, paediatric perioperative monitoring was limited to basic clinical observations, and was later supplemented with American Society of Anesthesiologists (ASA) standards on basic anaesthetic monitoring in most set-ups. Newer technology aimed to provide more accuracy like Masimo Signal Extraction Technology overcomes the challenges of movement and low perfusion artefacts during pulse oximetry. The noninvasive pulse co-oximetry (SpHb) seems a reliable way of monitoring the haemoglobin trend noninvasively. With an increasing trend of sicker children being operated for complex surgeries, newer monitoring modalities are being explored. Near-infrared spectroscopy used for measuring cerebral oxygenation during complex cardiac repairs has failed to show mortality benefit.[5] Many noninvasive technologies for cardiac output monitoring like oesophageal Doppler, pulse contour analysis, and bioimpedance show promising results in adults and are being evaluated in children. But these technologies based on adult algorithms will need fine tuning in children before they are accepted in routine practice.[6,7] The transcutaneous measurement of carbon dioxide is complementary to blood sampling and capnography in children and may find a role in procedural sedation monitoring without a definite airway.[7] Electroencephalography-based anaesthetic depth monitoring is increasingly being used in older children but lacks validity in infants and neonates. As per a survey among paediatric anaesthesiologists, the most frequently used depth of anaesthesia monitor was the bispectral index monitor with very few using Entropy, Narcotrend, and the Cerebral State Index.[8]

PAEDIATRIC AIRWAY

The Paediatric Perioperative Cardiac Arrest (POCA) registry and ASA demonstrated that despite better monitoring in terms of oxygenation, capnography and advances in anaesthetic medications, airway complications still continue to be one of the major contributing factors leading to perioperative cardiac arrest (27%) and brain death.[9]

Assessment of the airway is a key component in maintaining airway safety.[10]

The credibility of the Mallampati scoring system has been questioned in uncooperative children and thus many adopted more reliable Colorado Pediatric Airway Score [COPUR; C hin, O pening (mouth), P revious intubation difficulty and OSA, U vula, R ange (of movements)].[11] The prospective multicentre trial (NECTARINE; NEonate and Children audiT of Anaesthesia pRactice In Europe) found a higher incidence of difficult airway in children less than 60 weeks post-conceptual age, leading to severe hypoxaemia[12] and thereby, warranting a well-comprehensive plan for airway management in the preoperative phase. Nowadays, video laryngoscopes have taken a cardinal position in the armamentarium of paediatric difficult airway cart. A multicentric trial (VISI; Video laryngoscopy In Small Infants) inferred that among the anaesthetised infants, video laryngoscopy use with a standard blade improved the first-attempt success rate and brought down complications.[13] Traditionally, uncuffed endotracheal tubes (ETTs) were preferred in children aged less than 8 years due to the fear of mucosal injury causing subglottic stenosis. Magnetic resonance imaging has revealed rima glottidis as the narrowest part of the larynx in children. Consequently, this has encouraged the use of newly designed micro-cuffed tubes in the paediatric population. Not withstanding, the selection of an appropriate ETT size is pivotal and various formulae have been deployed for many years, but ultrasound is emerging as the latest tool for accurate measurement of the ETT size in children. In addition to this, recent advances in simulation-based training have become a valuable tool to enhance technical skills and teamwork execution during difficult airway management.[14] Despite the advancement in paediatric anaesthesia, the controversy regarding cuffed versus uncuffed ETTs persists.[15]

POINT-OF-CARE ULTRASOUND

Point-of-care ultrasound (POCUS), as a noninvasive diagnostic tool, is evolving in the paediatric population. Beyond the commonly used indications for invasive procedures under vision, POCUS applications like airway, lung, cardiac, and gastric ultrasound can be used to guide critical clinical decisions perioperatively. The role of ultrasonography in the selection of the correct size of ETT as opposed to height and age-based methods in the paediatric age groups has been investigated. Demet Altun, et al.[16] concluded from their study findings that subglottic diameter measured by ultrasound during apnoea appears to be reliable in estimating the appropriate size of a cuffed paediatric ETT. POCUS of the airway has the potential to evolve as a first-line noninvasive addendum assessment device in airway management.

While the use and popularity increases, we also need to be aware of the limitations of ultrasound.[17] Anaesthesiologists are still acquiring the skills and POCUS being an operator dependent skill, can deliver false results if not performed accurately. Similarly, direct extrapolation of adult data in children may not be reliable and studies to establish age or weight-based cut-offs while interpreting results may be required. Although available for intensive care and emergency setting, there are no guidelines so far for the structured use of POCUS in children perioperatively.

REGIONAL ANAESTHESIA

Regional anaesthesia (RA) in children has seen new horizons due to the increasing availability of ultrasound to the anaesthesiologists. Central neuraxial block, which was the gold standard of yesteryears is slowly being replaced with the truncal and peripheral nerve blocks–erector spinae plane block, paravertebral block, and quadratus lumborum block being among the popular few.[18] Ultrasound has allowed these blocks to be performed precisely, safely, and with lower volumes of local anaesthetic as compared to the blind techniques.[19] Dexmedetomidine has emerged as a useful adjunct to prolong the duration of action of peripheral nerve blocks in children.[20] But do newer techniques always translate to better outcomes? Fascial plane blocks have been implicated in higher incidence of local anaesthetic systemic toxicity due to the higher volume of local anaesthetic needed and faster absorption from these planes. Adjuvants to local anaesthetics in peripheral nerve blocks have been implicated in neurotoxicity. The safety of these procedures in children needs to be established with larger data.

The American Society of Regional Anesthesia and Pain Medicine (ASRA) and the European Society of Regional Anaesthesia and Pain Therapy (ESRA) Joint Committee worked on controversies of paediatric regional anaesthesia (PRA). They issued practice advisories on 1) the regional blocks either under sedation or general anaesthesia (GA); 2) the test dose for epidural; 3) identifying the epidural space, the use of air versus normal saline for loss of resistance; and 4) RA and the risk of obscuring compartment syndromes.[21]

PHARMACOLOGY

Not only are new chemical compounds discovered with the intention of maximising benefit with the least amount of negative effects but also newer mechanisms of delivery systems. The following are the new compounds that have emerged in the last decade:

1. Remimazolam, a new ultra-short-acting benzodiazepine (BZD), acts on gamma amino butyric acid-A (GABA_A) receptor, containing carboxylic ester moiety in its benzodiazepine core which permits rapid hydrolysis to inactive metabolites by nonspecific tissue esterase. Due to its property of high clearance, and minimal tissue accumulation, it has faster onset and quick recovery.[22] In paediatric patients, the initial dose is 0.2-0.3 μg/kg for induction, followed by 1 mg/kg/h (2 mg/kg/h of maximal infusion rate) for maintenance.

2. A novel micro to macro (M2M) approach of destabilising a microemulsion of propofol immediately prior to injection is developed which could improve stability and reduce pain on injection in children.[23]

3. Articaine belongs to the amide group of local anaesthetics with thiophene ring and an ester group that is metabolised by esterases in the tissues with a half-life of about 20 minutes. The faster onset and longer duration of action is because of increased lipid solubility and protein binding capacity of the drug, aiding in its diffusion into the tissues and lipid nerve membrane. In children, the maximum dose of articaine 4% with 1:1,00,000 epinephrine is half the lignocaine 2% with 1:1,00,000 epinephrine.[24]

Although the drug delivery systems are not very new [total intravenous anaesthesia (TIVA), target control infusion (TCI), and liposomal drugs], their use in paediatric patients has significantly increased in the last decade.

EFFECT OF ANAESTHESIA ON NEURODEVELOPMENT OF CHILD

Since the Food and Drug Administration[25] published their concern of association between general anaesthesia (GA) and neurocognitive abnormalities for children in 2016, many clinical researches have been attempted to determine the relation between GA and long-term neurocognitive effects. The three most prominent prospective studies, Mayo Anesthesia Safety in Kids (MASK),[26] general anesthesia spinal (GAS)[27] and Pediatric Anesthesia NeuroDevelopment Assessment (PANDA)[28] found that a single GA exposure was safe. In contrast, the MASK and PANDA studies found significant neurocognitive changes with multiple exposures but were unable to pinpoint the real culprit being the number of exposures or the duration of procedure. The GAS study found equivalence between GA and local anaesthesia, suggesting that long-term adverse neurocognitive outcomes could be the result of surgical procedures or other factors and not really the consequence of anaesthetic agents. A multicentric trial (T REX; Trial Remifentanil and dEXmedetomidine) is going on to establish the safety of dexmedetomidine.[29]

PAEDIATRIC ADVANCED LIFE SUPPORT GUIDELINES (2020)

With the ongoing advancements in medical science, the resuscitation guidelines[30] are updated every 5 years with the latest edition being released in 2020. The updates are discussed under three subheadings: prearrest, intra-arrest, and postarrest. Prearrest care recommends the use of extracorporeal life support and extracorporeal pulmonary resuscitation in children with acute myocarditis with arrhythmias, heart block, ST-segment changes, and/or low cardiac output with the idea of avoiding the onset of cardiac arrest. The fluid resuscitation in sepsis is modified to cautious fluid bolus of 10 ml/kg as compared to earlier 20 ml/kg with isotonic crystalloids with continuous monitoring and early addition of adrenaline or noradrenaline in fluid-refractory septic shock. While continuing the emphasis on high-quality cardiopulmonary resuscitation, the guidelines suggest early administration of adrenaline within 5 minutes for nonshockable rhythm. The most important change in intra-arrest care is the recommendation for higher respiratory rate (20-30 breaths/min) in children receiving cardiopulmonary resuscitation with advanced airway and during rescue breaths. Cuffed ETTs are found reasonable as they decrease the need for tube changes but with attention toward the size, position, and cuff pressure (<20 cm H₂O). The use of cricoid pressure is not recommended as it does not reduce the risk of regurgitation and may impede intubation success. Naloxone has been added for reversing respiratory arrest due to opioid overdose. Postarrest care continues to emphasise on maintaining homeostasis and targeted temperature management in unconscious children after attaining return of spontaneous circulation. The use of continuous electroencephalography monitoring in identifying nonconvulsive seizures has been added. Recovery link is new to “The Chain of Survival,” emphasising the role of postdischarge care in survivors.

SUMMARY

There are many advancements in the practice of paediatric anaesthesia [Table 1]. Updating the knowledge regarding recent advances helps in achieving better quality and safety in care. Although most advances follow from adults, they may not always be equally relevant in children. The global disparity in healthcare services limit the uniform access of these advancements. Nevertheless, they need to stand the test of time before advances can be considered the standard of care globally.

Table 1.

Key Points

Key Points

Enhanced recovery after surgery (ERAS), is a protocolised approach with simultaneous application of numerous pre-existing principles seeking to improve the overall outcome for the patients.

Fasting duration of 1 h for clear fluids is recommended.

Preoxygenation and apnoeic oxygenation improve safe period for intubation.

Advanced monitors - Masimo SET, NIRS, pulse contour analysis, electrical cardiography, thoracic bioreactance, bioimpedance, BIS (EEG) electrical cardiometry, impedance cardiography, bioimpedance and bioreactance have been described and validated.

Centrineuraxial blocks have been replaced by peripheral nerve blocks.

Remimazolam, Articaine are new drugs for paediatric usage.

MASK, GAS, and PANDA trials are crucial in giving conclusive remarks for effect of anaesthesia drugs on neurodevelopment of brain.

AHA-PALS 2020 guidelines have made many important modifications.

SET: Signal extraction technology; NIRS: Near-infrared spectroscopy; BIS: Bispectral index; EEG: Electroencephalography; MASK: Mayo Anesthesia Safety in Kids ; GAS: General anesthesia spinal trial; PANDA: Pediatric Anesthesia NeuroDevelopment Assessment; AHA-PALS: American Heart Association-Pediatric Advanced Life Support

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.