Clinical Vignettes on Hemostasis (Common Scenarios) - Hemostasis: Lesson 13
ฝัง
- เผยแพร่เมื่อ 3 ก.ค. 2024
- A discussion of 5 clinical vignettes with board-style multiple choice questions on the topic of hemostasis (i.e. pathology of platelets and the coagulation cascade).
#hematology #MedEd
(EDIT: Viewer Martin Welsh makes a great point below regarding Case #2, Question #2. In order to make the provided "correct" answer for this question more unambiguously correct, I should have made the patient more hypotensive than in the case, say something like 70/45.)
Let me know how you like this format for occasional videos (i.e. discussion of board-style MCQs on a focused topic). I'm already committed to doing one more such video for uncommon scenarios within the topic of hemostasis. If interest is high, I could also do some on other topics that I've covered in relative depth (e.g. anemia, liver disease, AKI/UAs, antiarrhythmics).
(The series on CXRs, EKGs, and ABGs all have practice cases already built into the videos themselves)
I would love to see more videos in this format.
Thanks for putting efforts in making these videos.
As a paramedic these videos have been invaluable to developing my understanding of medicine outside the confines of my ambulance.
I am curious regarding case 2, question 2 however: given the patient has such a severe derangement in coagulation and is now suffering from diffuse hemorrhages would the utility of fluids be almost zero? Increasing her BP is the obvious goal, but given the diffuse uncontrolled haemorrhages this would just increase the rate of bleeding as well as the dilutional anaemia/coagulopathy you discussed. Her MAP is floating just above 60, which is adequate to perfuse vital organs.
My answer would have been to prioritise reversing the coagulopathy with platelets and FFP (with monitoring for hypocalcaemia); followed by PRBC for the haemodynamics.
This is obviously a few steps outside my education, so would appreciate some corrections.
Thanks for the comment, and this is a great question and point of discussion!
To be honest, that case originally had a BP of 74/50 but I misspoke when I recorded it, and it was easier to change the slide than it was to rerecord that section of audio. In retrospect, I should have rerecorded the audio...
But even with a slightly higher BP, I think the priority would still be fluids. When I think about fluids in shock, particular hypovolemic shock, what's more important than her BP at this exact moment is what do I think the BP will be in 20 minutes. If the cause of bleeding was fully stopped (e.g. vascular injury that now repair with good hemostasis), then a BP of 84/50 sounds ok. But for a patient in acute DIC who still seems to be oozing blood, and even the operative hemostasis that you think the surgeon may think they achieved during the emergent hysterectomy may not be as robust as it appears, I think I'd want a little more cushion with the BP.
There is a mostly hypothetical phenomenon that increasing the BP above some minimum value necessary for organ perfusion may worsen blood loss from arterial hemorrhage (like sitting on a waterbed with a small leak - the added pressure of sitting on it will increase the rate of leaking). This wouldn't impact venous blood loss. And that's in addition to the effect of further diluting coagulation factors - though in acute DIC, I don't think it's obvious whether this specific effect would be detrimental or even beneficial since the initial trigger for the pathology is actually microthrombi.
There's a good summary of permissive hypotension here: www.ncbi.nlm.nih.gov/books/NBK558915/
By only minor gripe about the summary is that it implies the primary concern with fluids in massaive hemorrhagic is that it might decrease vasoconstriction (which otherwise would be helping to minimize blood loss), but a patient in hypovolemic shock is going to be maximally vasoconstricted whether their MAP is 50 or 60.
In short, permissive hypotension is something that probably has a role in penetrating trauma before intraoperative stabilization, but I don't think we have any idea whether the same principles would apply in a post-op patient actively in DIC.
As I write this response though, I am even more annoyed at myself for not making the patient in case 2 more hypotensive in order to make IV fluids more clearly the correct answer.
@@StrongMed Thankyou for the response, it has been very useful.
On further reflection of your comments in the video, and obviously with the revised blood pressure, I understand more clearly the answer: in such a critically ill patient like this the question isn't really whether or not she will receive fluids, but rather how much will she receive. While more definitive blood products will be used in the patients care, the obvious immediate treatment is to simply hang a bag. Pre-empting deterioration is a very good point that I had not fully appreciated.
In regards to permissive hypotension/restrictive fluid approaches: I agree that there is a dearth of evidence beyond that in trauma/peri-operative environment, however this exists at the same time as a lack of evidence for most pro-fluid recommendations. It does seem that whenever I revisit this topic the literature seems to move towards the restrictive approach (although I have made no attempt to understand the literature in it's entirety).
Wonderful work man..Thanx...
Great video!
Nicely explained.Music at the end of video is lovely
Best regards)