The most common organism causing bacterial tracheitis is:

Correct Answer: D

Rationale: Bacterial tracheitis is most commonly caused by Staphylococcus aureus, leading to severe airway obstruction.

Correct Answer: C

Rationale: Thrombin time is not commonly used as an initial screening test for bleeding disorders; instead, PT, PTT, and bleeding time are more relevant.

Correct Answer: B

Rationale: Rh incompatibility does not 'never' occur in first-born infants. While it is less common, sensitization can occur during delivery or other events in the first pregnancy, leading to hemolytic disease in the first-born infant.

Correct Answer: D

Rationale: Bacterial tracheitis is most commonly caused by Staphylococcus aureus, leading to severe airway obstruction.

Correct Answer: D

Rationale: Long-term corticosteroid use can lead to osteoporosis, hypertension, and diabetes mellitus, making 'All of the above' the correct answer.