A less invasive airway device — called a supraglottic airway device or SAD — was found to safely and effectively maintain breathing in pediatric patients with aromatic L-amino acid decarboxylase (AADC) deficiency during general anesthesia, according to a small study in Taiwan.
These SADs were used for children with AADC who were given anesthesia before undergoing routine medical procedures.
“None of the patients with AADC deficiency experienced … respiratory adverse events,” the researchers wrote, adding that the needed medical procedure “was successfully completed in all patients.”
Given that AADC patients are at higher risk of anesthesia-related respiratory complications, these findings highlight that SADs are safe and reliable for use in high-risk pediatric patients, the researchers noted.
The study, “Feasibility and Safety of Using Supraglottic Airway Devices for Pediatric Patients Undergoing Magnetic Resonance Imaging: A Case Series of High-Risk Patients,” was published in the Asian Journal of Anesthesiology.
AADC deficiency is caused by mutations in the DDC gene, which, as the disease’s name suggests, result in low levels of the AADC enzyme. That enzyme is necessary for the production of dopamine and serotonin, two neurotransmitters — chemical messengers used by nerve cells to communicate with each other.
Low levels of these neurotransmitters profoundly disrupt the communication between brain regions, and between the brain and other parts of the body, beginning at an early age.
This leads to developmental delays, intellectual disabilities, and muscle weakness. It also causes problems in the autonomic nervous system that controls involuntary body functions, such as blood pressure, breathing rate, and heartbeat.
The diagnosis and monitoring of AADC deficiency usually involve several exams, such as lumbar puncture, genetic tests, and magnetic resonance imaging, known as MRI scans. A lumbar puncture, or spinal tap, involves inserting a needle into the spinal canal to collect a small amount of cerebrospinal fluid, the liquid that surrounds the brain and spinal cord.
Both lumbar puncture and MRI require that the patient remain still for the whole procedure, which can be challenging for any child, let alone those neurologically impaired or with developmental delays. As such, general anesthesia — a combination of medications that induce a sleep-like state — is often used for high-risk pediatric patients undergoing such procedures.
However, most children with AADC deficiency already have impaired nerve cell communication. Thus, the nerve cell-suppressing effects of anesthesia, which can lower blood pressure, slow breathing rates, and reduce the heartbeat, may pose added risks for these pediatric patients.
Clinicians, therefore, advise that these patients be closely monitored while on general anesthesia to rapidly detect and manage any complications.
Several airway devices are available to help maintain breathing while on anesthesia, the researchers noted, adding that SADs — fully, supraglottic airway devices — have “recently become more popular than endotracheal tubes.”
SADs, which sit above the glottis — the main valve between the passages to the lungs and the stomach — are shorter, quicker- and easier-to-insert tubes than standard endotracheal tubes, which are inserted all the way through the windpipe.
The insertional procedure of SADs is less invasive and less traumatic, requires a lower dose of anesthetics, and is associated with lower airway complication rates. Some SADs, including the i-gel, also allow for the aspiration of liquids that have leaked upward from the stomach to prevent their entry into the lungs, which can cause lung infections.
While a few studies have evaluated the feasibility and safety of using SADs for general anesthesia during MRI scans in healthy children, none included children with neurological or developmental problems.
Now, a team of researchers in Taiwan retrospectively analyzed the safety of using SADs for airway maintenance in 30 children (17 boys and 13 girls) with neurological and developmental disabilities who received anesthesia for MRI.
All procedures were conducted at a single Taiwanese center between October 2016 and July 2018 and SADs used included the i-gel and laryngeal mask airways (LMA).
The children’s median age was 4 years (range, 1.6–17.0 years), and 19 of them (63.3%) were at higher risk for anesthesia-related complications, including 10 with AADC deficiency. To avoid additional anesthesia, AADC deficiency patients also underwent lumbar puncture for diagnostic testing before the MRI.
A total of 38 MRIs (66% of them in the brain) were included and analyzed. Among them, 20 (53%) were made using i-gel, while 18 (47%) were done using the reusable Ambu LMA.
MRI scans lasted a mean of 50.9 minutes, and the children were under anesthesia for a mean of 83.7 minutes; the duration being longer than the MRI due to the additional lumbar puncture procedure in those with AADC deficiency.
Results showed that all MRI scans were completed without interruption and produced images with adequate quality, according to a specialized radiologist. No respiratory, heart, or blood pressure problems were reported throughout the MRI for all children.
Before the anesthesia, a 5-year-old boy with AADC deficiency experienced airway collapse and severe gastroesophageal reflux, which occurs when stomach contents flow back into the tube connecting the mouth and stomach.
During his lumbar puncture, large amounts of stomach content were detected close to the i-gel and subsequently sucked through the SAD.
Lower-than-normal blood pressure was observed in one 9-year-old child with AADC deficiency during anesthesia induction, and it was resolved with appropriate medication. Temporary lower-than-normal heartbeat was detected in an 8-year-old child during post-MRI follow-up that resolved without treatment.
These findings highlight that “using both reusable Ambu LMA and i-gel for airway maintenance during MRI is feasible and safe for pediatric patients including high-risk children, such as patients with AADC deficiency,” the researchers wrote.