Pediatric Anesthesia 2008 18: 303–307 doi:10.1111/j.1460-9592.2008.02446.x Pediatric laryngospasm DARRYL HAMPSON-EVANS FRCA*, PATRICK MORGAN FRCA† AND MARK FARRAR FRCA* *Consultant in Anaesthesia, St. George’s Hospital, London, UK and †Specialist Registrar in Anaesthesia, Anaesthetic Department, St. George’s Hospital, London, UK Summary Pediatric laryngospasm is an anesthetic emergency. It is a relatively common phenomenon that occurs with varying frequency dependent on multiple factors. In view of this and the clear risks to the patient when it occurs, a consensus committee has been established to deter- mine the evidence based management of this condition. This article will cover the definition, causes and recognition of laryngospasm and the evidence behind a proposed algorithm for its’ management. Keywords: pediatric; laryngospasm; algorithm Introduction simulation centers and subsequently in operating theatres. Currently there is a lack of a nationally agreed algorithm for the management of pediatric laryngospasm. Definition The national collaborative pediatric simulation Laryngospasm can be defined as glottic closure due project, Managing Emergencies in Paediatric Anaes- to reflex constriction of the laryngeal muscles; it can thesia (MEPA), has led to the need for an evidence be complete or partial. Sumner and Hatch (2) define based algorithm. MEPA is designed to provide True Laryngospasm as ‘complete closure of the simulator based exposure to pediatric emergencies larynx caused by external stimulation’. Here the and is supported by The Royal College of Anaes- ventricular cords (false vocal cords) are tightly thetists and The Association of Paediatric Anaesthe- occluded, the paraglottis (intralaryngeal part of the tists (1). epiglottis) moves posteriorly and the arytenoids The MEPA committee is a national group, made cartilages both perform a ventral movement thus up of pediatric anesthetists with experience in effectively sealing the larynx. simulation. Their aim has been national consensus They describe glottic spasm as different from on the theory behind the treatment of emergencies in true complete laryngospasm. In partial spasm both pediatric anesthesia. This has been achieved by a vocal cords are firmly pressed against each other, review of the available literature and discussion to leaving a small lumen open at the posterior form an algorithm that is evidence based and commissure which allows minimal ventilation by educationally fit for use in crisis management. an anesthetist. The authors present a review of the literature and As it is difficult to distinguish between true the algorithm agreed by MEPA committee in 2006 laryngospasm and glottic spasm most clinicians for the management of pediatric laryngospasm. This describe both as laryngospasm. Therefore clinically will hopefully allow a structured approach to this it seems more useful to define laryngospasm as common problem to be taught and developed in complete or partial (3). Complete laryngospasm – chest movement but Correspondence to: Darryl Hampson-Evans, Anaesthetic Depart- ment, St. George’s Hospital Blackshaw Road, London SW 17 0QT, silent with no bag movement and no ventilation UK (email: [email protected]). possible. Ó 2008 The Authors Journal compilation Ó 2008 Blackwell Publishing Ltd 303 304 D. HAMPSON-EVANS ET AL. Partial laryngospasm – chest movement but lignocaine and topical lignocaine to the vocal cords stridulous noise with a mismatch between the (10–14), magnesium sulphate (15), acupuncture (16) patients’ respiratory effort and the small amount of and the use of 5% carbon dioxide for 5 min prior to bag movement. extubation (17). However, none of these methods has been shown to abolish laryngospasm completely. Incidence To manage laryngospasm effectively it first needs to be recognized. Once recognized, most agree a Laryngospasm occurs more commonly in pediatric similar protocol although there are a number of anesthetic practice than in adults. The incidence is reports that are not common place. Of less frequently twice that of adults in older children and three times used techniques there are two worthy of note. that of adults in younger children (4). This correlates to 17 events in 1000 anesthetics in children up to Pressure in the laryngospasm notch 9 years. This increases to 64 ⁄ 1000 in children with obstructive lung disease and 96 ⁄ 1000 in those with The notch is found behind the lobule to the pinna of acute upper respiratory tract infections. This latter each ear bounded anteriorly by the ascending ramus incidence can last for up to 6 weeks following acute of the mandible adjacent to the condyle, posteriorly by infection (5). the mastoid process and cephaloid by the base of the Other studies support this but also show that skull (18,19). The technique involves firm pressure at young age and supervision by less experienced and this clearly defined point that causes pain over the non-pediatric anesthetists, increases the incidence of styloid process. The afferent input is thought to cause laryngospasm (6). Those children passively exposed relaxation of the cords by a poorly defined mecha- to cigarette smoke also show increased incidence nism. This maneuver may also open the airway. (7,8). Pull of Mandible Cause This technique can be used when true spasm cannot Laryngospasm occurs during anesthesia for two be broken (2). It involves a vigorous forward pull of reasons: firstly, a lack of inhibition of glottic reflexes the mandible. This causes a painful stimulus and because of inadequate central nervous system stretches the geniohyoid muscle to ventralise the depression and, secondly increased stimuli (2). paraglottis. Rapid bagging through a now partially Causes of stimulation at an inappropriate depth of open larynx will break most cases of laryngospasm. anesthesia include extubation, secretions or blood Although both of these techniques may have their irritating the vocal cords, stimulation of the airway place, they seem hard to support as a sole technique. by an artificial airway, laryngoscope or suction They may be able to be incorporated as an appendix catheter. to an algorithm for use in the management of laryngospasm. Recognition Superior laryngeal nerve block has been reported as a method to treat laryngospasm but has not been Laryngospasm is identified by varying degrees of adopted by many (20). Topical cocaine has been airway obstruction with paradoxical chest move- trialled after GA for endoscopy (21). ment, intercostal recession and tracheal tug. A Of the more accepted protocols for the manage- characteristic crowing noise may be heard in partial ment of laryngospasm options include maintaining a laryngospasm but will be absent in complete laryn- clear airway while administering 100% oxygen with gospasm. CPAP and avoiding further instrumentation of the airway until the cords relax (2,3). Attempts to Management provide intermittent positive-pressure ventilation with a face mask may distend the stomach, splinting There are a number of ways reported to reduce the the diaphragm and make subsequent resolution of incidence of laryngospasm (9). These include IV hypoxia more difficult (2). Ó 2008 The Authors Journal compilation Ó 2008 Blackwell Publishing Ltd, Pediatric Anesthesia, 18, 303–307 PEDIATRIC LARYNGOSPASM 305 ) The next step in management depends on whether IM Succinylcholine (4 mgÆkg 1) (32,34) in to a there is complete or partial laryngospasm. If there is large muscle bulk such as the quadriceps has been no bag movement then complete laryngospasm is shown to produce 90% twitch suppression in present and some of the maneuvers above may be 295 s. If this is given via the submental route this useful. In complete spasm CPAP may make the reduces to 265 s which can be reduced to 133 s if situation worse by forcing the area just above the the intralingual injection site is digitally massaged false cords against each other closing the entrance to (35). the, larynx (2,22,23). Therefore if complete spasm Although these times seem prolonged, the clinical cannot be broken early IV agents should be effect to allow oxygenation is anecdotally reported to considered. be much less than the time for 90% twitch suppres- The gold standard still seems to be Succinylcho- sion, which is more appropriate for intubation. ) ) line (1–2 mgÆkg 1) with Atropine (0.02 mgÆkg 1)if A recent editorial by Walker and Sutton concen- there is bradycardia. Some authors have recom- trated on the use of Succinylcholine via intra- mended a smaller dose of Succinylcholine muscular, intra-lingual, submental and intra-osseous ) (0.1 mgÆkg 1) be used (24). The other main intra- routes. The intra-osseous route for administration of venous agent that can break laryngospasm is medication and fluids is widely accepted in the ) Propofol (0.5–0.8 mgÆkg 1) (25–27). Most studies emergency setting. However, due to the lack of have not used Propofol in the younger age groups published evidence supporting its use in the treat- (<3 years) and its role to break complete spasm ment of laryngospasm, we have excluded this when bradycardia is present has not been defined. If particular route in our algorithm (36) Figure 1. the stimulus is a painful one perioperatively then the We feel the development of one algorithm for use of a short acting opioid such as Alfentanil can be the management of pediatric laryngospasm and used (28). However, this may also lead to apnoea understanding of the evidence that formed it is with less optimal intubating conditions than follow- essential. Attention should be concentrated on ing Succinylcholine. airway assessment and the presence or absence Other IV agents reported in the literature include of bag movement. doxapram (5 patients) (29) and nitroglycerine (2 patients) (30). The low patient numbers in these Conclusions studies here exclude them from this protocol. Management of laryngospasm that fails to There is no level one evidence to support a definitive improve with simple measures appears fairly protocol for the management of laryngospasm. simple to treat when IV access is available but Most evidence is from small studies with small becomes more of an issue when no cannula is treatment groups and case reports.