Pediatric Anesthesia ISSN 1155-5645
ORIGINAL ARTICLE
Does the Miller blade truly provide a better laryngoscopic view and intubating conditions than the Macintosh blade in small children? Elsa Varghese1 & Ratul Kundu2 1 Department of Anaesthesiology, Kasturba Medical College & Hospital, Manipal University, Manipal, India 2 Department of Anaesthesiology and Critical Care, Institute of Post Graduate Medical Education and Research, Kolkata, India
Keywords child; laryngoscopes; airway devices; general anesthesia; techniques Correspondence Dr Ratul Kundu, Department of Anaesthesiology and Critical Care, Institute of Post Graduate Medical Education and Research, 244 AJC Bose Road, Kolkata, West Bengal 700020, India Email: [email protected] Section Editor: Charles Cote Accepted 26 February 2014 doi:10.1111/pan.12394
Summary Background: Both Miller and Macintosh blades are widely used for laryngoscopy in small children, though the Miller blade is more commonly recommended in pediatric anesthetic literature. The aim of this study was to compare laryngoscopic views and ease and success of intubation with Macintosh and Miller blades in small children under general anesthesia. Materials and Method: One hundred and twenty children aged 1–24 months were randomized for laryngoscopy to be performed in a crossover manner with either the Miller or the Macintosh blade first, following induction of anesthesia and neuromuscular blockade. The tips of both the blades were placed at the vallecula. Intubation was performed following the second laryngoscopy. The glottic views with and without external laryngeal maneuver (ELM) and ease of intubation were observed. Results: Similar glottic views with both blades were observed in 52/120 (43%) children, a better view observed with the Miller blade in 35/120 (29%) children, and with the Macintosh blade in 33/120 (28%). Laryngoscopy was easy in 65/120 (54%) children with both the blades. Restricted laryngoscopy was noted in 55 children: in 27 children with both the blades, 15 with Miller, and 13 with Macintosh blade. Laryngoscopic view improved following ELM with both the blades. Conclusion: In children aged 1–24 months, the Miller and the Macintosh blades provide similar laryngoscopic views and intubating conditions. When a restricted view is obtained, a change of blade may provide a better view. Placing the tip of the Miller blade in the vallecula provides satisfactory intubating conditions in this age group.
Introduction Laryngoscopy blade designs have been influenced by individual airway anatomy and the laryngoscopic views obtained. Airway anatomy in infants and children differs from that of adults, and a combination of factors may contribute to difficult laryngoscopy or intubation in smaller children. These include a relatively large head and tongue, a narrow floppy ‘u-’shaped epiglottis, and an anteriorly placed acute-angled larynx with anteroposterior caudally angulated vocal cords. Robert Miller was © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 24 (2014) 825–829
the first to design a straight-bladed laryngoscope with a curved distal tip (1). Sir Robert R Macintosh designed a shorter blade for adults, and to lift the epiglottis indirectly, the tip of the blade was placed in the vallecula (1,2). Straight-bladed laryngoscopes have been advocated in children
ORIGINAL ARTICLE
Does the Miller blade truly provide a better laryngoscopic view and intubating conditions than the Macintosh blade in small children? Elsa Varghese1 & Ratul Kundu2 1 Department of Anaesthesiology, Kasturba Medical College & Hospital, Manipal University, Manipal, India 2 Department of Anaesthesiology and Critical Care, Institute of Post Graduate Medical Education and Research, Kolkata, India
Keywords child; laryngoscopes; airway devices; general anesthesia; techniques Correspondence Dr Ratul Kundu, Department of Anaesthesiology and Critical Care, Institute of Post Graduate Medical Education and Research, 244 AJC Bose Road, Kolkata, West Bengal 700020, India Email: [email protected] Section Editor: Charles Cote Accepted 26 February 2014 doi:10.1111/pan.12394
Summary Background: Both Miller and Macintosh blades are widely used for laryngoscopy in small children, though the Miller blade is more commonly recommended in pediatric anesthetic literature. The aim of this study was to compare laryngoscopic views and ease and success of intubation with Macintosh and Miller blades in small children under general anesthesia. Materials and Method: One hundred and twenty children aged 1–24 months were randomized for laryngoscopy to be performed in a crossover manner with either the Miller or the Macintosh blade first, following induction of anesthesia and neuromuscular blockade. The tips of both the blades were placed at the vallecula. Intubation was performed following the second laryngoscopy. The glottic views with and without external laryngeal maneuver (ELM) and ease of intubation were observed. Results: Similar glottic views with both blades were observed in 52/120 (43%) children, a better view observed with the Miller blade in 35/120 (29%) children, and with the Macintosh blade in 33/120 (28%). Laryngoscopy was easy in 65/120 (54%) children with both the blades. Restricted laryngoscopy was noted in 55 children: in 27 children with both the blades, 15 with Miller, and 13 with Macintosh blade. Laryngoscopic view improved following ELM with both the blades. Conclusion: In children aged 1–24 months, the Miller and the Macintosh blades provide similar laryngoscopic views and intubating conditions. When a restricted view is obtained, a change of blade may provide a better view. Placing the tip of the Miller blade in the vallecula provides satisfactory intubating conditions in this age group.
Introduction Laryngoscopy blade designs have been influenced by individual airway anatomy and the laryngoscopic views obtained. Airway anatomy in infants and children differs from that of adults, and a combination of factors may contribute to difficult laryngoscopy or intubation in smaller children. These include a relatively large head and tongue, a narrow floppy ‘u-’shaped epiglottis, and an anteriorly placed acute-angled larynx with anteroposterior caudally angulated vocal cords. Robert Miller was © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 24 (2014) 825–829
the first to design a straight-bladed laryngoscope with a curved distal tip (1). Sir Robert R Macintosh designed a shorter blade for adults, and to lift the epiglottis indirectly, the tip of the blade was placed in the vallecula (1,2). Straight-bladed laryngoscopes have been advocated in children
