The use of heat and moisture exchange filter (HMEF) has become a routine standard of care in general anesthesia (GA), more so, during the current COVID-19 pandemic times. However its routine use, especially in pediatric patients, has several issues. We report a case of increased dead space ventilation in a pediatric patient due to the presence of HMEF. Hypercapnia and its cause was instantly diagnosed with two capnography sampling lines placed at two ends of the HMEF.

Phenylketonuria (PKU) is an inborn error of metabolism caused by a deficiency of the enzyme phenylalanine hydroxylase which results in accumulation of phenylalanine. Patients of PKU presents with seizures, mental retardation, and organ damage and possess a unique challenge to the anesthesiologists when they need anesthetics for diagnostic or surgical procedures. There is limited literature regarding the safety of various anesthetic drugs in PKU patients. None of them reported the use of dexmedetomidine as safer sedative option for such patients. Therefore, we describe the management of such a case posted for magnetic resonance imaging under dexmedetomidine sedation.