Question 2b

Last updated Sun, 04/30/2017 - 18:12
 Topic: Cardiac Arrest and Resuscitation
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Other SAQs in this paper:

A 58 year old man is brought in by ambulance moribund with barely palpable pulse and a sinus tachycardia.


(b)  His condition improves with therapy.   When his wife arrives she tells of his recent hip replacement complications by a bleeding duodenal ulcer. What are the likely diagnoses? 
How will you establish the definite diagnosis and why? 

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College Answer

(b) This provides some help.but is not definitive. Possible causes still include pulmonary embolus. hypovolaemia from bleeding DU. myocardial infarction etc. A progression from simple/quick investigations to more complex but specific/diagnostic investigations should be outlined. There should have beeo a sense of appropriate priorities.

If there are signs of GIT bleed with hypovolaemia, then fluid resuscitation, NG tube insertion, endoscopy, FBC and coag screen will be indicated  along with anti-ulcer therapy and perhaps surgery.

If there are signs of acute myocardial infarction. in the setting of recent DU, angiogram and angioplasty would be a preferable course perhaps after urgent echo.

If there are signs of massive pulmonary embolus (right  heart failure), and initial tests are supportive (right heart strain on ECG, oligaemic lung on CXR, distended RV on echo), a spiral CT would be indicated with commencement of IV heparin

Discussion

This part of this multi-part question offers some explanation as why the patient is "moribund". In essence, it narrows the differentials generated by the "4 Hs and 4 Ts" approach, which one can use to systematically organise one's diagnostic approach to this peri-arrest scenario in the first part of this question.

In detail:

  • Hypoxia is possible due to pulmonary oedema or atelectasis
  • Hypovolemia is a differential, given the history of GI bleeding
  • Hyper/hypokalemia is now less likely
  • Hyper/hypothermia is also less likely
  • Tension pneumothorax is unlikely given the history
  • Tamponade (i.e. cardiac tamponade) cannot be excluded but again, does not fit the history
  • Toxins (eg. anaphylactic reaction or intoxication) cannot be ruled out, especially given the recent surgery and thus the potential oral antibiotic therapy
  • Thrombus (eg. a PE or MI) is a definite possibility - particularly the PE - given the recent history of orthopaedic surgery

Thus, one would organise the following investigations:

  • Routine bloods to measure urea and haemoglobin, to investigate the possibility of a GI bleed
  • CXR to exclude pneumothorax, atelectasis and APO, as well as to look for subdiaphragmatic gas associated with a perforated duodenal ulcer
  • TTE to investigate myocardial contractility and to look for regional wall motion abnormalities associated with MI. Even a low-skilled interpreter will also be able to rapidly rule out cardiac tamponade and right ventricular dilatatation associated with massive PE.
  • CTPA to exclude massive PE; the CT will also capture a portion of the upper GI tract giving more information regarding the state of affairs in the duodenum.
  • Upper GI endoscopy would be the gold standard to investigate and manage duodenal bleeding, and one should contact a gastroenterologist to organise this.

The following specific management could be commenced while awaiting results:

  • High flow oxygen therapy
  • Volume resuscitation
  • PPI infusion

Seeing as both bleeding and thrombosis are a part of the differentials, anticoagulation/thrombolysis should be thought about but left until investigations reveal more about the cause of this shock state.

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