Current (or within past 3 months) history of apnea requiring an apnea monitor
Active, current respiratory issues that are different from the baseline status (pneumonia, exacerbation of asthma, bronchiolitis, and respiratory synctitial virus)
Unstable cardiac status (life threatening arrhythmias, abnormal cardiac anatomy, and significant cardiac dysfunction)
Craniofacial anomaly, which could make it difficult to effectively establish a mask airway for positive pressure ventilation if needed