Transcript
CHAPTER 28</P></ANS></ANSSET></MCQSET>
Clinical Reasoning Checkpoint Answers
MP, a 32-year-old male, is in the trauma intensive care unit (TICU) as the result of a motorcycle–tree crash. MP has multiple fractures and contusions. On ICU day 7, MP’s status begins to deteriorate, and it is determined that he has developed sepsis. On ICU day 8, the nurse notes petechiae on MP’s trunk. In addition, oozing of blood is noted from several discontinued intravenous insertion sites and suture lines. The nurse suspects that MP may be developing disseminated intravascular coagulation (DIC) and contacts the Intensivist. The following labs are ordered: Bleeding Time, Platelet Count, PT and aPTT, Factor I (Fibrinogen), Fibrin Degradation Product (FDP), and D-dimer.
Briefly explain the basis for the nurse’s suspicion that MP has developed DIC.
Answer: The rapid development of petechiae and new oozing from wounds such as old IV sticks and suture lines is very suspicious, suggesting abnormal dissolution of previously plugged wounds. This should not occur under normal circumstances. MP has sepsis, and DIC most commonly develops as a complication of sepsis (a complication of a complication).
For each lab ordered by the Intensivist: (a) Indicate whether the value would be abnormally elevated or decreased if MP has DIC; and (b) see if you can explain the reason for the abnormality.
Lab Test (units)
Elevated or Decreased
Reason for Abnormality
Bleeding Time (minutes)
Platelet Count (cells)
Prothrombin (PT) (seconds)
Factor I (Fibrinogen) (mg/dL)
FDP (mcg/dL) and D-dimer (mg/dL)
Answer:
Lab Test (units)
Elevated or Decreased
Reason for Abnormality
Bleeding Time (minutes)
Elevated
(> 6 minutes)
Bleeding time is a measure of the length of time it takes for bleeding to stop. It becomes prolonged with reduced platelet levels (thrombocytopenia).
Platelet Count (cells)
Decreased
(less than 150,000)
Formation of platelet plugs is the initial stage of clot formation. In DIC, systemic activation of platelets rapidly consumes them, thus causing decreased levels—and bleeding.
Prothrombin (PT) (seconds)
Elevated
(PT greater than 15 sec.)
Prothrombin, the factor II clotting factor, is a precursor of the clotting process. It requires conversion to its active form, thrombin. Measuring the PT actually reflects the status of multiple clotting factors (Factors I, II, V, VII, and X). Prolongation of PT reflects a reduction in (consumption of) the clotting factors.
Factor I (Fibrinogen) (mg/dL)
Decreased
(Less than 100 mg/dL)
Fibrinogen is acted on by thrombin to form fibrin strands needed for clot formation. Decreased levels suggest overconsumption of fibrin (see FDP).
FDP (mcg/dL) and D-dimer (mg/dL)
Elevated
(FDP >10 mg/dL; D-dimer >250 mg/dL)MP
Fibrin strands are a crucial part of clot formation. In the later part of the coagulation cascade, clots are broken down. When fibrin breaks down, its degradation (split) products promote anticoagulation and fibrinolysis (clot busting). When FDP is elevated, it causes bleeding. D-dimer is a fibrin degradation fragment that increases with fibrinolysis.
MP develops oliguria (abnormally low urine output) and azotemia (elevated serum nitrogen waste products) as a result of his DIC. Briefly explain the significance of this problem and how it can result from DIC.
Answer: In DIC, platelets become activated, triggering prothrombotic activities that particularly affect the microcirculation. Microthrombi can form anywhere in the body and any organ can become ischemic and damaged. In MP’s case, microthromboses likely have affected his renal circulation, causing damage sufficient to lead to his oliguria and azotemia, which suggest kidney injury.
MP’s platelet count is 45,250, and his latest laboratory values show that he has significant hypofibrinogenemia. What interventions can the nurse anticipate in response to these values?
Answer: He may receive platelet concentrates to increase his platelet count, particularly if he is actively bleeding. To treat his low fibrinogen level, he may receive cryoprecipitate. Fresh frozen plasma (FFP) might also be considered based on the status of his other coagulation factors.
While providing supportive therapy for MP, what is the most important goal for treating his DIC?
Answer: Correcting MP’s sepsis is the most crucial part of his management. To reverse the DIC, MP’s sepsis must be brought under control and reversed. Finding the source of the sepsis is sometimes difficult, particularly in complex trauma patients.
