Pediatric Anesthesia ISSN 1155-5645

REVIEW ARTICLE

Total intravenous anesthesia will supercede inhalational anesthesia in pediatric anesthetic practice Gillian R. Lauder Department of Pediatric Anesthesia, British Columbia’s Children’s Hospital, Vancouver, BC, Canada

Keywords anesthesia; pediatric; total intravenous anesthesia; drugs; propofol; remifentanil; dexmedetomidine Correspondence Gillian R. Lauder, Department of Pediatric Anesthesia, British Columbia’s Children’s Hospital, 4480 Oak Street, Vancouver, BC V6H 3V4, Canada Email: [email protected]

Summary Inhalational anesthesia has dominated the practice of pediatric anesthesia. However, as the introduction of agents such as propofol, short-acting opioids, midazolam, and dexmedetomidine a monumental change has occurred. With increasing use, the overwhelming advantages of total intravenous anesthesia (TIVA) have emerged and driven change in practice. These advantages, outlined in this review, will justify why TIVA will supercede inhalational anesthesia in future pediatric anesthetic practice.

Section Editor: Neil Morton Accepted 9 September 2014 doi:10.1111/pan.12553

‘If you always do what you always did, you will always get what you always got’. [Albert Einstein]

Introduction The first intravenously administered anesthetic, followed by long-term recovery, was performed successfully on a dog in 1656 (1). Unfortunately, a number of factors were responsible for the lack of translation to potential use in human clinical practice, principally the lack of a hollow bore needle for injection. The lack of appreciation of intravenous anesthesia potential meant that nearly 200 years past before the speciality of anesthesia was born, with the demonstration of the first ether anesthetic in Boston by William TG Morton in 1846. Inhalational anesthesia has dominated the practice of pediatric anesthesia ever since because barriers to the use of total intravenous anesthesia (TIVA) also prevented its early widespread adoption. However, since the introduction of agents such as propofol, short-acting opioids, midazolam, and dexmedetomidine a monumental change has occurred. With increasing use, the overwhelming 52

advantages of TIVA have emerged and driven change in practice. These advantages, outlined in this review, will justify why TIVA will supercede inhalational anesthesia in future pediatric anesthetic practice. As a TIVA enthusiast, working in an anesthetic department that converted from inhalational anesthesia to predominantly TIVA over 15 years ago, I present this flagrantly biased perspective. The advantages cited will be supported with available evidence. Where no evidence is published and with the understanding that ‘absence of evidence is not evidence of absence’ (2) consensus impressions gleaned from years of departmental clinical experience, working with TIVA, will also be presented. Pharmacology Propofol, 2,6 di-isopropylphenol, is a highly lipophilic anesthetic agent presented in a lipid emulsion of soybean oil and egg lecithin. The pharmacokinetics of propofol are now well described in children. Data are available through the age range from neonates to maturity for healthy children and also in the presence of comorbidities and/or critical illness (3–14). © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 25 (2015) 52–64

G.R. Lauder

Bolus dose propofol After intravenous (IV) administration of a bolus of 3–5 mgkg 1 of propofol loss of consciousness occurs within 30–60 s with drug delivery to the central nervous system (CNS). The time taken for equilibration of the plasma propofol concentration (Cp) with the propofol concentration at the effect site (Ce) following a bolus loading dose is relatively constant (approximately 4 min). There is little variation in the time to peak Ce even when the rate of injection varies widely. Hence, a slow induction time will minimize respiratory depression where maintenance of spontaneous ventilation (SV) is required. The blood concentration-time profile of propofol after an i.v. bolus injection follows a three-compartment model. Firstly, immediate distribution from systemic circulation to brain and liver, redistribution to the rapidly equilibrating compartment of the abdominal viscera and muscles then subsequent distribution to the slowly equilibrating but much larger peripheral compartment of the adipose tissue. The half-lives for each of these compartments are 2–4 min, 30–45 min, and 3–63 h, respectively. Children have a much larger central compartment than adults, and therefore require an increased bolus dose and higher initial infusion rate (15). Elimination of the drug from the body occurs from the central compartment with hepatic glucuronidation and renal excretion. Clearance of propofol is high at rates of 50 mlkg 1min 1, but clearance rates are even higher in children, which contributes to the requirements of an increased rate of maintenance infusion doses (16). Conversely, neonates have markedly reduced and widely variable clearance. Postmenstrual age (gestational age and chronological age) and postnatal age of

Total intravenous anesthesia will supercede inhalational anesthesia in pediatric anesthetic practice.

Inhalational anesthesia has dominated the practice of pediatric anesthesia. However, as the introduction of agents such as propofol, short-acting opio...
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