cardiac/cardiac monitoring and support Flashcards
Conditions associated with bradycardia
Autonomic
-Raised ICP
-Visceral pain
-Drugs (beta blockers)
-Epidural
Non autonomic
-MI
-Hypoxia
-Hypothermia
-Hypothyroidism
Heart territories ecg
Anterior: V1-V4
Inferior: 2, 3, aVf
Posterior infarct: Isolated ST depression V1, V2
Treatment of STEMI
-Aspirin
-PCI followed by anticoagulation with heparin/LMWH/thrombolysis
-glycoprotein 2b/3a inhibitors
-Glycaemic control
-Beta blockers
-Thrombolysis if pci not availabe if not contraindicated
Contraindications to thrombolysis:
<2 weeks post op
-Active peptic ulcer
-Previous haemorrhagic stroke
-Recent head injury
-Prolonged traumatic CPR
What main parameters affect cardiac function?
Preload
Intrinsic cardiac function
Afterload
Describe the causes of cardiac failure
Factors affecting preload:
-Hypovolaemia
-Fluid overload
-Pneumothorax/cardiac tamponade
Factors affecting intrinsic myocardial function
-ACS
-Arrythmia
-Chronic heart failure + ‘operative stress’
-Pneumothorax/cardiac tamponade
-Electrolyte disturbance (e.g. cardiac tamponade)
Conditions affecting afterload
-Aortic stenosis
-PE
-Pneumothorax/cardiac tamponade
-Aortic dissection
How would you manage someone in acute heart failure?
-CCRISP principles
-Oxygen, sit pt up, CPAP if practicable
-Stop IVI
-IV diuretics (80mg furosemide IV)
-IV morphine (2.5-5mg diamorphine) to aid vasodilatation (reduce afterload)
-Nitrates (patch, sublingual/buccal/IV)
-ECG
-Tx underlying cause (Arrythmia/PE/tamponade)
What is the definition of cardiogenic shock?
-Severe impairment of cardiac function with hypotension <90mmhg or 30mmhg less than patients ‘normal’systolic
What is the most common cause of cardiogenic shoci?
Ischaemia/infarction
What are the important points in managing a patient with a pacemaker?
-Any pt undergoing surgery should have had recent pacemaker check
-Diathermy should be as far from pt as possible (e.g. on thigh or under buttocks). Never put it behind the pacemaker
-Short bursts of diathermy rather than long bursts
-Bipolar is safer
-Avoid diathermy near pacemaker
What is the definition of shock?
-Acute circulatory failure, with inadequate tissue perfusion causing cellular hypoxia
What are the most common mechanisms of shock?
-Hypovolaemic
-Cardiogenic
-Obstructive
-Vasodilatory
What are the causes of hypovolaemic shock? (preload)
-Haemorrhage
-Dehydration
-Fluid loss
Causes of cardiogenic shock (intrinsic cardiac function)
-MI
-Arrythmia
-Heart failure
-Cardiac contusions due to trauma
Causes of obstructive shock (intrinsic myocardial function)
-PE (obstruction to right ventricular outflow)
-Cardiac tamponade (construction on heart)
-Pneumothorax (pressure on heart)
Vasodilatory (afterload)
-Sepsis
-Neurogenic shock
-Anaphylaxis
-Adrenal insufficiency
Neurogenic shock
-Follows spinal transection (above level of T6) or brainstem injury with loss of sympathetic outflow beneath the level of the injury and consequent vasodilation
What is the definition of cardiogenic shock?
-Inadequate tissue perfusion resulting directly from myocardial dysfunction
CVP interpretation
High CVP (>15mmhg)–> right ventricular/biventricular failure
Low CVP (<5mmhg) –> hypovolaemia
Normal CVP: >8mmhg
Static measurement can be misleading; young pt may have normal CVP due to vasoconstriction but may be underfilled
FLuid challenge can resolve doubt: small fluid challenge can be given (100-200ml) and then CVP measured, if significant rise and remains high this suggests myocardial failure/dysfiunction
What are the indications for invasive cardiac monitoring?
-Failure to maintain cardiovascular homeostasis with simple measures
-Procedures that give rise to rapid/profound changes in preload or afterload, e.g. AAA repair
-Treatement with vasoactive drugs that influence preload/afterload/myocardial function, to monitor response to treatment
-Pts at risk of developing low perfusion states e.g. high risk pt with poor cardiac function
What is the CVP a measurement of?
-Preload
-Pressure within SCV as it enters right atrium, reflects ability of right heart to accept and deliver circulating volume
What influences the CVP?
-Venous return
-Right heart coimpliance
-Intrathoracic pressure
What are the indications for a central line?
-Administration of fluid replacement therapy for hypovolaemia when conventional access not possible, e.g. when concern exists about overtransfusion when there is uncertainty about fluid volume status
-Measure effect of vasoactive drugs on venous capacitance, particularly vasodilators
-To aid diagnosis of right heart failure: high pressure with low cardiac output
-Administration of potent drugs e.g. inotropes
-TPN (needs dedicated clean lumen)
Complications of central line
Related to insertion
-Haemotoma/haemothorax
-Tension pneumothorax
-Air embolus
-Extravascular catheter placement
-Neuropraxia
-Lymphatic puncture
-Tracheobronchial puncture
-Sepsis
Related to catheter
-Knotting of catheter
-Catheter breakage
Descrbibe noradrenaline receptor/effect/clinical use
Receptor
-Alpha adrenoreceptor agonist
Effect
-Arteriolar vasoconstriciton
Clinical use
-Septic shock with low SVR
Describe Adrenaline receptor/effect/clinical use
Receptor
-Alpha and beta adrenoreceptor agonist, predominantly beta 1 adrenoreceptor agonist at low doses
Effect
-Positive inotropic and chronotropic. Vasoconstricts at high doses
Clinical use
-Widespread in conidtions of low cardiac output: usful in emergency situations
Dopamine
Receptor:
-Alpha and beta adrenoreceptors. Dopamine (DA) 1 and 2 receptors
Effect:
-Low dose: splanchnic vasodilatation, increased renal and hepatic blood flow (DA1). High dose: vasoconstriction
Clinical use
-Used less frequently
Dobutamine
Receptor:
-DA1, DA2 and beta adrenoreceptor agonist
Effect
-Reduses SVR and increases cardiac output
CLinical use
-Cardiogenic shock
What are the functions of the kidney?
-Elimination of water soluble waste products of metabolism other than CO2
-Elimination of water soluble drugs
-Fluid and electrolyte homeostasis
-Acid-base balance
-BP control: RAAS system
-Endocrine function: EPO and vitamin D production
What is normal urine output?
Normal: 1.5-2ml/kg/hr
Oliguria: <0/5
Anuria: <100ml/day
What is the definition of AKI
-Abrupt (within 48 hrs) reduction in kidney function defined as absolute increase in creatinine of >26 micromol/L OR
-Percentage increase in serum creatinine level of >50% from baseline OR
-Reduction in UO (oliguria <0.5ml/kg/hr for >6 hrs)
What are common causes of AKI?
Prerenal:
-Hypovolaemia
-Sepsis
-Low cardiac output
Intrinsic renal
-ATN
-Nephortoxics: drugs, contrast
-Abdominal compartment syndrome
-Hepatorenal syndrome
-Glomerulonephritis
Post renal
-Bladder outflow obstruction
-Bilateral ureteric obstruction
What are nephrotoxic drungs?
-ACE inhibitors
-NSAIDS
-Diuretics
-Aminoglycosides
Indiciations for renal replacement therapy
Absolute:
-Refractory hyperkalaemia (>6mmol/L)
-Refractory pulmonary oedema and fluid overload
-Uraemic encephalopathy
Relative
-Acidosis (pH <7.2)
-Uraemia
-Pericarditis
-Toxin removal
What is the emergency treatment for hyperkalaemia?
-Continuous cardiac monitoring
-Insulin (10-20 units actrapid) in 100ml 20% dextrose intravenously over 30 minutes
-Sodium bicarb 50mmol intravenously over 5-10 mins
-10% calcium gluconate IV (10-30 ml)
-B2 agonist: nebulised salbutamol
