Shock Flashcards
84 year old female admitted with loss of consciousness. BP is 76/44. HR is 40. No other history available.
Diagnosis: cardiogenic shock due to inappropriate HR
HR inappropriately low for BP→ most likely bradyarrhythmia → unable to mount a stroke volume to maintain BP e.g. if myocardium lacked elasticity (myocardial fibrosis), or outflow obstruction (aortic stenosis, mitral stenosis). Vaso-vagal episode would manifest in the same way.
Investigation: essential immediate test is an ECG, which would show complete heart block, with an escape rhythm, or a sinus bradycardia.
Treatment: atropine → reverses vagally mediated bradycardia, and will reassert the blood pressure. If unsuccessful, use of more potent chronotropes (e.g. isoproteranol), or external pacing.
Other possibilities: inferior wall myocardial infarction causing complete heart block, hypothyroidism, and overdosing on nodal blocking drugs – beta blockers, calcium channel blockers and digoxin.
A 43 year old female is admitted to ICU with acute pancreatitis. She develops acute respiratory distress syndrome and is managed with difficulty with high oxygen requirements, prone positioning, high levels of PEEP and vasopressor. On day 29 following admission, the patient, who had been hemodynamically stable, without support, on minimal ventilation settings, acutely deteriorates. Her blood pressure falls to 60/40. SpO2 is 80%, heart sounds are inaudible, heart rate is 45, jugular veins are distended.
This patient has a tension pneumothorax. The differential diagnosis is sepsis and myocardial dysfunction. The acute onset, hemodynamic insufficiency and absence of heart sounds support the diagnosis. The other signs that may be present are absence of breath sounds on one side, and tracheal deviation away from that side. Urgent placement of a chest drain is required.
Dx: cardiogenic shock due to inflow obstruction.
A 42 year old female is transferred from another hospital for chemotherapy. Two days prior to transfer the patient had undergone a laparotomy for a hysterectomy. The procedure was abandoned when the surgeon realized that there was an inoperable tumor present in the pelvis, and there was a considerable amount of blood loss, which continued into the post-operative period.
Hours after transfer the patient becomes initially hypoxemic and subsequently hypotensive. Her temperature is 37 degrees Celsius, her heart rate is 140, blood pressure is 80/36, ECG shows a sinus tachycardia, SpO2 is 79%. The patient’s hemoglobin is 10.2g/l, and creatinine is 1.4.
What is your differential diagnosis, and how would you manage this patient?
This patient has an appropriate heart rate response to hypotension. The differential diagnosis is between hypovolemia due to continued blood loss (unlikely with a normal range hemoglobin), cardiac inflow or outflow obstruction and septic shock. The history of hypoxemia preceding hypotension is suggestive of a cardiorespiratoty problem. Initial oxygen therapy and airway control is followed by aggressive volume loading. There is no evidence of a myocardial problem, and given the history of pelvic surgery and surgery, cardiac inflow-outflow obstruction due to pulmonary embolism is the most likely scenario. This diagnosis needs confirmation – echocardiography (if not stable enough to travel) or, ideally a spiral CT scan or pulmonary angiogram. If this is a pulmonary embolism, anticoagulation, thrombolysis or pulmonary embolectomy is required.
Echocardiogram shows a hyperdynamic heart and an empty left ventricle, consistent with inflow obstruction. The patient remained hypotensive and hypoxemic, and the decision was taken to proceed with thrombolysis, with good results.
Dx: cardiogenic shock, outflow obstruction, pulmonary embolism.
A 63 year old male is admitted through the ER. He presented with acute shortness of breath. On admission his BP was 90/50, heart rate 110, PaO2 80 on 100% oxygen. His ECG shows left ventricular hypertrophy with T wave across his antero-lateral leads. His chest x-ray shows cardiac hypertrophy with bilateral infiltrates. He has a history of hypertension, treated with lisinopril, and has a 40 pack-year history of smoking.
What is your diagnosis and how would you manage this patient?
This is pump failure with diastolic dysfunction. This patient has acute left ventricular failure with pulmonary edema. The treatment is oxygen, followed by preload reducing agents – furosemide or nitroglycerin. Intravenous morphine will reduce the patients suffering.
Dx: cardiogenic shock, pump failure.
A 22 year old male motorcyclist is involved in a accident. He arrives in the ER intubated and hypotensive. His blood pressure is 82/40, minimal urinary output, heart rate 130, fractured left acetabulum, fractured left femur, flail chest on the right, normal cardiac silhouette, grade 2 liver laceration. His hemoglobin is 9.2g/L, creatinine 1.6, and creatine kinase 1084, MB 15%. ECG: ST segment elevation along anterior leads.
What is the diagnosis, and how would you manage this patient?
This patient has undergone extensive chest trauma, with almost certain cardiac contusion. A contused segment of myocardium will behave in a similar manner to infracted tissue with the anticipation that functional recovery will occur. The presence of ST segment elevation may represent actual ischemia due to disruption of a coronary artery. The patient undoubtedly has systolic dysfunction, requires volume loading and inotropic support until an intra-aortic balloon pump has been placed. The patient requires urgent angiography and perhaps surgical intervention.
Dx: cardiogenic shock, pump dysfunction.
A 27 year old male is involved in an motor vehicle accident. He sustains a burst fracture of T2 with complete neurological deficit below this level. Fours hours following admission his SpO2 is 85%, his blood pressure is 80/40 and his heart rate is 45.
This unfortunate young man has spinal shock as a result of disruption of both the spinal cord and the sympathetic tract. He is hypotensive due to loss of sympathetic tone to the lower part of his body, and bradycardic, due to loss of his cardioaccelerator nerves. He has relative hypovolemia, and inability to compensate. The treatment initially is airway protection and volume loading, with blood/colloid, as necessary. If this is insufficient to restore the blood pressure, this patient will require a systemic sympathetic analogue to tighten up his blood vessels and increase his heart rate: the choice is either dopamine or epinephrine. Dx: distributive shock, loss of vasomotor tone, relative hypovolemia, inappropriate heart rate.
Explain the determinants of blood pressure
