Introduction
Anaesthetic complications occur in all patients, including those with Down syndrome — however, the likelihood of such complications is considerably higher in individuals with Down syndrome than in the general population. Awareness of the most common complications enables anaesthetic teams to develop safer plans. Planning a safe anaesthetic requires a thorough patient assessment and medical history review by a trained anaesthetist. Direct consultation with the anaesthetist well in advance of a planned procedure may be essential where the medical or behavioural history warrants it.
Why Do Individuals with Down Syndrome Require Anaesthesia?
Between 40 and 60 percent of children born with Down syndrome have significant cardiac defects, most of which require early surgical intervention. Early cardiac surgery has been one of the most important factors in improving survival rates for people with Down syndrome since the 1960s. Other congenital anomalies requiring early surgical intervention include oesophageal, gastrointestinal, and urinary tract problems. Surviving these major health challenges also means a greater likelihood of developing chronic health conditions in later life that may require surgical intervention — just as with the general population.
Aspects of Down Syndrome Most Likely to Affect Anaesthetic Safety
Many aspects of Down syndrome must be considered when planning a safe anaesthetic. Before any sedation or anaesthesia is administered, a thorough review of current medical issues, relevant history, allergies, medications, and surgical and anaesthetic history is essential, along with a physical examination to the extent the patient permits.
The most important considerations include: behaviour and communication, airway obstruction and obstructive sleep apnoea, bradycardia, gastro-oesophageal reflux disease, atlanto-axial instability, and airway size.
How Behaviour and Communication Issues Affect Anaesthesia
Individuals with Down syndrome may exhibit heightened anxiety and distress when placed in unfamiliar environments such as a clinic or operating theatre. Severe anxiety can trigger sympathetic nervous system responses ("fight or flight") that may contribute to anaesthetic complications. In many cases, calm communication between the healthcare professional, the patient, and their carer is sufficient; however, pre-operative sedation may sometimes be necessary.
It is important for family members and carers to display calm, reassuring behaviour during assessment and preparation. Since receptive language skills typically exceed expressive abilities in individuals with Down syndrome, they are acutely aware of anxiety in those around them and will respond accordingly. Communication difficulties may also prevent them from expressing pain or nausea, and they often struggle to describe their pain in detail — including location, duration, intensity, and character.
How Sleep Apnoea and Airway Obstruction Affect Anaesthesia
Individuals with pre-existing airway obstruction during sleep are particularly susceptible to obstruction under anaesthesia. Under the influence of sedatives and anaesthetic agents, patients lose protective airway reflexes — such as the cough and gag reflexes — and muscle tone, causing airway tissues to approximate. For those whose airways are already prone to collapsing during normal sleep, the loss of these reflexes alone may be sufficient to cause obstruction.
Airway obstruction is dangerous because it prevents oxygen from reaching the lungs, and prolonged obstruction can be fatal. Anaesthetists are trained to manage airway obstruction by various means, including intubation. In rare cases, a surgical incision in the neck may be necessary. A pre-operative sleep study is not routinely required; however, complex procedures or a history of previous anaesthetic airway difficulties may warrant one.
How Anaesthesia Affects Heart Rate
Up to 50 percent of individuals with Down syndrome may develop bradycardia — including rates slow enough to constitute asystole — during anaesthesia or sedation. Significant slowing of the heart rate leads to a drop in blood pressure, impairing oxygen delivery to vital organs. Although children may be more susceptible than adults, the risk remains significant across all age groups.
Cardiac valve abnormalities — most notably mitral valve prolapse — affect approximately 50 percent of adolescents and adults with Down syndrome and can adversely affect circulatory stability during anaesthesia. Physical examination, electrocardiography, and echocardiography are used to assess valve disease. Anaesthetists should enquire about any suspected valvular disease prior to proceeding.
How Gastro-oesophageal Reflux Disease (GERD) Affects Anaesthesia
GERD is a significant anaesthetic consideration because it increases the risk of aspiration. Sedation and anaesthesia suppress the natural protective reflexes that coordinate swallowing and coughing. When impaired, the patient cannot protect their airway from acid refluxing up the oesophagus, which may enter the lungs and cause irritation, inflammation, or life-threatening bronchospasm. Fasting prior to anaesthesia exists solely to prevent aspiration.
Individuals with Down syndrome are more prone to acid reflux, have weaker cough reflexes, show higher rates of obesity, and experience significantly higher rates of pneumonia — a combination that substantially increases the risk of aspiration and its associated complications.
How Atlanto-axial and Atlanto-occipital Instability (AAI/AOI) Affects Anaesthesia
Individuals with Down syndrome are at increased risk of upper cervical and craniocervical joint instability, placing them at greater risk of serious spinal cord injury. Manipulating the head and neck to open the airway and position airway devices is an expected component of nearly every anaesthetic. If the patient has AAI or AOI, this routine manoeuvre may carry significant danger.
Maintaining a neutral head and neck position during airway instrumentation is usually sufficient to prevent spinal cord injury; however, this position may hamper successful intubation. Pre-operative cervical spine imaging or medical clearance from a neurologist or neurosurgeon may be necessary before proceeding.
How Airway Size Relates to Anaesthesia
The laryngeal and tracheal diameter in individuals with Down syndrome is generally smaller than average, and they may also present with subglottic stenosis or tracheomalacia. Smaller endotracheal tubes than would typically be used are therefore required, and this must be borne in mind to prevent avoidable injury to the trachea, vocal cords, or larynx.
Other Considerations Affecting Anaesthesia in Down Syndrome
Difficult intravenous access — due to obesity and dry skin — may complicate drug administration. Additional conditions to consider include: autoimmune disorders, diabetes, dementia, depression, epilepsy, hypotonia, obesity, and osteoporosis. Anaesthetic staff should ask detailed questions about the patient's full medical and surgical history, as prior conditions may have lasting sequelae that directly affect anaesthetic safety.
Source: Information in this section has been reproduced under an exclusive agreement with the National Down Syndrome Society (NDSS). Available at: www.ndss.org