For example: char a; a= getchar(); The function getchar() reads a single character from the standard input device, the keyboard being assumed because that is the standard input device, and assigns it to the variable a.
This excludes acute and chronic respiratory failure (518.84), acute respiratory distress (518.82), acute respiratory failure following trauma and surgery (518.51), chronic respiratory failure (518.83), respiratory arrest (799.1), and respiratory failure, newborn (770.84). This applies to respiratory failure NOS.
Ideally, coders should assign code 518.81 rather than code 518.51 even when the respiratory failure occurs during the postoperative phase. However, without more accurate code definitions, the acute respiratory failure will be incorrectly classified as a complication of the surgical procedure.