NEJM reviews

Question 1

What are the most common organisms in aspiration pneumonia today?

Answer 1

S. pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Enterobacteriaceae, whereas gram-negative bacilli, including P. aeruginosa, were found without anaerobes in hospital-acquired cases

Institutionalised elderly (Gram-negative enteric bacteria accounted for 49% of the pathogens)

Question 2

Most common cause of death for haemolytic transfusion reactions

Answer 2

ABO-incompatible transfusions

(But it’s TACO for general transfusion related deaths)

Question 3

What is the rate of acute haemolytic reactions in non cross matched blood (e.g. trauma)

Answer 3

1 in 2000

Question 4

Where does red cell destruction occur in delayed haemolytic transfusion reactions?

Answer 4

Extravascularly in liver/spleen due to incomplete complement activation through C3b opsonization and monocyte-and-macrophage

Question 5

What is the most common cause of haemolysis after infusion of hematopoietic cells for transplantation or after solid-organ transplantation?

Answer 5

Incompatibility between the donor’s plasma and the recipient’s red cells, termed minor ABO incompatibility, with subsequent red-cell destruction in the recipient

Question 6

Timing of delayed haemolytic transfusion reactions

Answer 6

2 days to 1 month

Question 7

Management of acute haemolytic transfusion reactions

Answer 7

Send off blood/transfusion/urine samples

Management must occur in an intensive care unit, along with a renal consultation, since dialysis may be required

Vigorous hydration with isotonic saline to maintain urine output at a rate above 0.5 to 1 ml per kilogram of body weight per hour is recommended to minimize the effects of free heme-mediated renal and vascular injury