Safe paediatric procedural sedation — formative SAQs

SAQ 1 (10 marks)

A 5-year-old, ASA I, presents to the emergency department with a displaced forearm fracture requiring urgent reduction. He last ate a light meal three hours ago. The team plans procedural sedation. [1] [2]

1. Define procedural sedation and analgesia, and outline the four levels of the sedation depth continuum with the responsiveness, airway and ventilation criterion for each. (4) [2]
2. Describe the structured pre-sedation assessment you will perform at the bedside before any drug is given. (3) [2]
3. State how you will use the fasting history, and defend your decision to proceed or delay. (3) [6]

Model answer — SAQ 1

(1) Definition and the sedation continuum (4). Procedural sedation and analgesia is a monitored, titrated, drug-induced depression of consciousness that allows an unpleasant or painful procedure to be performed while protective airway reflexes, spontaneous ventilation and cardiovascular function are preserved. The ASA continuum has four levels. In minimal sedation (anxiolysis) the child responds normally to verbal command and airway, ventilation and cardiovascular function are unaffected. In moderate or conscious sedation the child shows purposeful response to verbal command or light tactile stimulation, the airway is maintained independently and spontaneous ventilation is adequate. In deep sedation the child responds only purposefully to repeated or painful stimulation, the airway may require active intervention and spontaneous ventilation may be inadequate. In general anaesthesia the child is unarousable even to painful stimulus, the airway usually cannot be maintained without intervention and ventilation is frequently inadequate. The practical boundary is that deep sedation and general anaesthesia carry the risk of airway loss and require anaesthetic-level training. [2]

(2) Structured pre-sedation assessment (3). I perform a fixed pre-sedation check. First, I assign the ASA physical status class (ASA I or II is suitable for sedation by a trained team; ASA III or above needs anaesthetic input). Second, I take the history: age and weight in kilograms for dosing, the procedure to be performed and its anticipated pain and duration, the fasting history, recent upper airway infection or wheeze, snoring or sleep-disordered breathing, reflux or vomiting, previous sedation or anaesthetic problems, allergies and the past medical history. Third, I perform a focused airway assessment looking for mouth opening, neck movement, mandibular recession, visible tonsils and any stridor, and a cardiorespiratory examination recording baseline observations. Before the drug I confirm a two-person team, rescue airway equipment (suction, bag-valve-mask, age-appropriate airway adjuncts, oxygen) at the bedside, continuous monitoring with a baseline, and vascular access where the agent requires it, and I document consent. [2]

(3) Fasting history and the decision to proceed (3). I take the fasting history and use it to inform the risk and the depth of sedation, but I would proceed with sedation now. The evidence on pulmonary aspiration risk during emergency procedural sedation shows it is negligible and is not predicted by fasting status; aspiration is prevented by sedation depth and airway care rather than by the time since the last meal. The ASA elective fasting intervals (2 hours clear fluid, 6 hours light meal) were designed for elective anaesthesia and should not delay a child in pain needing a time-critical reduction. The current position, reflected in the guidelines, is that fasting is not a substitute for monitoring. I would choose an agent and depth matched to the child's risk, ensure rescue equipment and a dedicated observer are present, use capnography, and proceed. [6]

SAQ 2 (10 marks)

During ketamine dissociative sedation for the fracture reduction, the child develops stridor and paradoxical chest movement, and the oxygen saturation begins to fall. [3] [4]

1. What is the most likely diagnosis, and what is the stepwise immediate management? (4) [3]
2. Explain why capnography is preferred over pulse oximetry alone for monitoring during procedural sedation. (3) [4]
3. Outline the recovery and discharge criteria you will apply once the procedure is complete. (3) [2]

Model answer — SAQ 2

(1) Diagnosis and stepwise management (4). The most likely diagnosis is laryngospasm — sudden closure of the vocal cords following airway irritation, more common with a recent upper respiratory infection. The stepwise management is: first, clear secretions and apply sustained positive airway pressure with 100 percent oxygen via a tightly sealed bag-valve-mask using a firm jaw thrust; second, if positive pressure does not break the spasm, give suxamethonium (1 to 1.5 milligrams per kilogram intravenously, or 4 milligrams per kilogram intramuscularly if no access) to paralyse the cords and allow ventilation, with preparation for intubation; and third, call for senior and anaesthetic help and review the plan. If the episode were transient hypoxia or apnoea rather than laryngospasm, the response would be verbal or tactile stimulation, airway-opening manoeuvres, bag-valve-mask ventilation with 100 percent oxygen and withholding further sedation. [3]

(2) Capnography over pulse oximetry alone (3). Pulse oximetry measures arterial oxygen saturation, so it falls only after hypoventilation has progressed far enough to drop the alveolar oxygen, and supplemental oxygen masks the fall further by keeping the saturation normal even as the carbon dioxide climbs. Capnography measures exhaled (end-tidal) carbon dioxide and detects the rising carbon dioxide of hypoventilation within seconds, before the saturation falls. A randomised trial in a paediatric emergency setting confirmed capnography detects hypoventilation that oximetry misses, which is why current guidelines recommend it wherever available and why relying on pulse oximetry alone is a recognised pitfall. [4]

(3) Recovery and discharge criteria (3). I recover the child in a monitored area with continuous pulse oximetry and a dedicated observer until discharge criteria are met. The structured tool is the modified Aldrete score, assessing activity, respiration, circulation, consciousness and oxygen saturation; a score of 9 or above, sustained over a period of observation, supports discharge. The child should be alert or at their baseline conscious state, have a patent airway and adequate breathing, stable cardiovascular observations, and be able to tolerate oral intake. Recovery time varies by agent — nitrous clears within minutes of stopping, ketamine over roughly 60 to 120 minutes. I admit if recovery is prolonged, if any serious adverse event occurred, or if the child is an infant at higher risk of late apnoea, and I give the family aftercare advice: supervision by a responsible adult, no driving or cycling, and return precautions for drowsiness, breathing problems or vomiting. [2]