015 Canine Haemoabdomen - Part 1

Some Things To Know...

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Recent (April 2015) Facebook post (Veterinary ECC Small Talk page, ER Vet Tech Rounds group):

“When You Hear About A 'Collapsed Dog' What Are The Top Three Differentials That Come To Mind?”

Approximately 150 responses
Haemoabdomen in particular due to splenic rupture mentioned by approximately 80% of respondents

Episode loosely based around:

Herold LV, Devey J, Kirby R, Rudloff E. Clinical evaluation and management of hemoperitoneum in dogs. J Vet Emerg Crit Care 2008. 18(1):40-53.

“This clinical review combines a search of the veterinary literature with the clinical experience of the authors to provide a resource for the emergency management of hemoperitoneum in dogs.”

1. Causes:

Traumatic vs. non-traumatic

NON-TRAUMATIC cases of clinically significant canine haemoabdomen most common – especially rupture of intra-abdominal tumours – especially haemangiosarcoma lesions

Other non-traumatic causes:

  • Haematoma rupture
  • Systemic coagulopathy due to e.g. vitamin K antagonist anticoagulant rodenticides, Angiostrongylus vasorum (canine lungworm)
  • Gastric dilation-volvulus (GDV)
  • Liver torsion
  • Splenic torsion
  • Etc.
“Don’t assume that every dog with a non-traumatic haemoabdomen has a tumour and in particular please don’t go chopping open dogs that have a primary systemic coagulopathy!”

Obviously some dogs will have a secondary consumptive coagulopathy that needs to be managed along with the primary problem.

Clinically significant TRAUMATIC haemoabdomen relatively rare?
Focused abdominal ultrasonography (A-FAST) may reveal small clinically insignificant bleeds more commonly?

2. Canine abdominal haemangiosarcoma:

A dog with a non-traumatic haemoabdomen:

  • What is the probability that this individual dog has a bleeding structural mass lesion as the cause?
  • What is the probability that that bleeding lesion is a tumour rather than a haematoma?
  • If it is a tumour, what is the probability that it is haemangiosarcoma?

Sweeping superficial summary of some papers listed below – papers not been critiqued for quality/reliability:
Malignant neoplasia most common cause of non-traumatic haemoabdomen in dogs occurring in approximately 65-85% of cases
Of those approximately 60-75% are haemangiosarcoma lesions

3. History, Clinical Signs and Physical Examination:

Will depend to an extent on:

  • Cause
  • Single/multiple bleeding episodes
  • Severity of current bleeding episode

Not all cases are collapsed

 “At least 40 mL/kg of peritoneal fluid is required to detect a fluid wave, making abdominal distension an insensitive indicator of early or slow forming free abdominal fluid.”

Radiography more sensitive, ultrasonography even more sensitive
40 ml/kg cut-off: is a universal cut-off rational across breeds, standing vs. recumbent, all palpators? Evidence for this figure??

“Four objectives must be met during resuscitation efforts: (1) to re-establish and maintain effective circulating volume, (2) to diagnose hemoperitoneum and identify database abnormalities, (3) to maintain oxygen-carrying capacity, and (4) to arrest ongoing hemorrhage. The actions to achieve these goals are often undertaken simultaneously depending on the severity of clinical signs. When clinical signs indicating decompensatory shock are present, immediate resuscitation will preclude definitive diagnostic evaluation; however, a rapid assessment of the packed cell volume (PCV), total solids (TS), and abdominocentesis results can be evaluated to confirm a diagnosis of hemoperitoneum.”

Make sure to provide analgesia as needed.

4. Re-establish and maintain effective circulating volume:

How best to resuscitate haemorrhagic hypovolaemia?
Overly aggressive crystalloid resuscitation harmful; rapid increases in intravascular hydrostatic pressure may blow off clots and promote further/on-going bleeding
We can’t leave the patient in a shocked state and on the flipside we don’t want to exacerbate the haemorrhage. So what do you do?

Careful conservative titrated resuscitation; end-point is adequate but not necessarily normal systemic perfusion
Stop resuscitation when end-point reached and continue to monitor closely
Assess and resuscitate perfusion using physical examination parameters – supplemented by blood pressure and lactate if available

‘Hypotensive resuscitation’:

Resuscitate systemic blood pressure to a low-normal end-point (e.g. mean arterial blood pressure (MAP) 60 mmHg; Doppler systolic 80-90 mmHg)
But:
Do not use blood pressure in isolation; systemic blood pressure is a proxy for but not the same thing as systemic perfusion
Ensure non-invasive blood pressure measurements are repeatable/reliable/

See podcast episode 009 for discussion of resuscitation fluids and crystalloids versus colloids

Haemoglobin-based oxygen-carrying solutions provide both oxygen-carrying capacity and colloidal support:

  • Oxyglobin® only one currently available; not in all countries
  • Potentially very expensive resuscitation strategy

‘Haemostatic resuscitation’:

Not mentioned in review article
Replace lost whole blood with comparable blood products – packed red blood cells, plasma, platelets
Increasingly adopted and researched in human medicine; also use of specific clotting factors/clotting factor combinations and antifibrinolytics especially tranexamic acid.
Minimises harm from not replacing like-for-like, also dilutional coagulopathy etc.

Very unrealistic in vast majority of veterinary practice environments? Adequate and timely access to blood components? Financially affordable strategy for pet carers?

5. Diagnosing haemoabdomen:

Venous manual packed cell volume (PCV) and plasma total solids (TS):

May suggest acute haemorrhage – does not localise to abdominal cavity

Both red blood cells and protein are lost from the circulation in haemorrhage and therefore PCV and TS do not change initially:

  • Remember that PCV is a percentage and TS a concentration, i.e. neither is a measure of absolute quantity.
  • In the first few minutes following haemorrhage, the absolute number of red blood cells and plasma protein molecules will be reduced but PCV and TS are unchanged.
  • Fluid then moves from the interstitial compartment into the bloodstream diluting the remaining red cells and protein and causing a decrease in the measured PCV and TS.
    • It takes a while for fluid shift and therefore dilution to occur although it is not possible to be too precise about the exact length of time in clinical patients.
    • In dogs the spleen contracts in response to haemorrhage and expels a large amount of stored red blood cells into the circulation; therefore PCV may remain in the normal range for a while despite low TS, i.e. with blood loss, TS is usually expected to fall first followed by PCV in dogs.
    • The response of the spleen in cats is either much less substantial or in fact non-existent depending on which reference one consults.
  • As yet more time passes PCV will also fall depending on whether haemorrhage is on-going, the severity of any on-going haemorrhage, and any treatment instituted.

Evaluate for systemic coagulopathy

 “Resuscitation efforts should not be delayed while awaiting laboratory results.”

…and I couldn’t agree with that more.

Identify free peritoneal fluid – ultrasonography best way to do this
Aspirate – including potentially with ultrasound guidance – and analyse
Blood lost into the abdomen (and other cavities) often has an echogenic appearance

When analysed the fluid will:

  • Be grossly sanguineous but non-clotting
  • Have a PCV that is similar to (could be lower, same or higher than) the patient’s circulating PCV
  • Have red blood cells, possible occasional erythrophagocytosis, and typically no platelets on cytology
    • Note: although cytology is not required to diagnosis haemoabdomen, it should always be performed to exclude the presence of a concurrent septic process which would then make surgery an emergency following stabilisation.

Beware of over-interpreting fluid aspirated from any body cavity as being consistent with haemorrhage purely based on gross appearance. It is not unusual for fluid to grossly appear consistent with bleeding only for PCV measurement to then be inconsistent – grossly sanguineous fluid can for example have a PCV of less than 5-10%.

“Repeated paracentesis during stabilization and hospitalization provides information to monitor the progression of intra-abdominal bleeding. An increasing trend in the abdominal PCV that parallels a decreasing trend in the peripheral PCV indicates ongoing or active hemorrhage.”

Note that intravenous resuscitation with red cell-free fluids – including plasma – may affect both venous and effusion PCV and hence laboratory evaluation.

Part 2 includes maintaining oxygen-carrying capacity, arresting haemorrhage, possible use of abdominal counterpressure etc.

Papers that informed this episode:

Aronsohn MG, Dubiel B, Roberts B, Powers BE. Prognosis for acute nontraumatic hemoperitoneum in the dog: a retrospective analysis of 60 cases (2003-2006). J Am Anim Hosp Assoc 2009. 45(2):72-77.

Hammond TN, Pesillo-Crosby SA. Prevalence of hemangiosarcoma in anemic dogs with a splenic mass and hemoperitoneum requiring a transfusion: 71 cases (2003-2005). J Am Vet Med Assoc 2008. 232(4):553-8.

Herold LV, Devey J, Kirby R, Rudloff E. Clinical evaluation and management of hemoperitoneum in dogs. J Vet Emerg Crit Care 2008. 18(1):40-53.

Lux CN, Culp WTN, Mayhew PD, et al. Perioperative outcome in dogs with hemoperitoneum: 83 cases (2005–2010). J Am Vet Med Assoc 2013. 242(10):1385-1391.

Pintar J, Breitschwerdt EB, Hardie EM, Spaulding KA. Acute nontraumatic hemoabdomen in the dog: a retrospective analysis of 39 cases (1987-2001). J Am Anim Hosp Assoc 2003. 39(6):518-522. 

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