Flashcards in Revision Deck (33):
ST-segment-elevation myocardial infarction (STEMI) s always accompanied by chest pain
The elderly and diabetics may not have chest pain.
During the acute phase, there is a substantial risk of VF.
May present with S-T depression in leads V1-3 of a 12-lead ECG YES: A posterior STEMI will show S-T depression in leads V1-3.
New LBBB is diagnostic of STEMI.
When using transcutaneous pacing: Electrical capture typically occurs with a current of 5-10 amps NO: Capture typically occurs with a current of 50-100mA, ie. 100 times less.
Hyperkalaemia may prevent successful pacing.
If there is lot of movement artefact on the ECG this may be misinterpreted by the pacemaker and inhibit it.
A QRS complex does not guarantee myocardial contractility. Absence of a pulse in the presence of good electrical capture constitutes PEA.
With regard to the ECG:
Adhesive defibrillator pads should only be used in an emergency to assess the cardiac rhythm.
Electrodes should be placed over bone rather than muscle to minimise interference from muscle artefact.
The normal PR interval is between 0.12 and 0.20 second (3-5 small squares)
The normal QRS complex interval is < 0.12 second (< 3 small squares)
There are no differences in the treatment of victims of fresh or sea water drowning.
Resuscitation should be considered even if the patient has been submersed in water for 10 minutes: Start and continue resuscitation unless clear evidence resuscitation attempts are futile.
Cardiac arrest is usually a secondary event following a period of hypoxia. Resp arrest first
Prophylactic steroids and antibiotics have not been shown to be of benefit in preventing chest infection.
You arrive at the bedside 4 minutes after cardiac arrest of a 70 kg woman. An IV line is in place, and there is no pulse. The ECG confirms asystole. Two nurses are performing CPR competently. You would recommend:
The treatment of asystole does not include defibrillation.
Sodium bicarbonate: Routine use not recommended and is associated with a number of significant side-effects.
Calcium chloride: Indicated only for PEA caused by hyperkalaemia, hypocalcaemia and overdose of Ca blocking drugs
Adrenaline 1 mg IV should be given as soon as intravascular access is achieved in patients in asystole.
PaO2: 22.6 kPa (FiO2 85%)
> 11 kPa on air
pH 7.11 7.35 – 7.45
PaCO2 7.2 kPa 4.7 – 6.0 kPa
Bicarbonate 14 mmol l-1
22 – 26 mmol l-1
Base excess -10.6 mmol l-1
+2 to -2 mmol l-1
A decrease in blood pH below 7.35 indicates an acidaemia.
The PaO2 should be numerically about 10 less than the inspired concentration. In this case this would be > 60kPa.
There is no compensatory increase in base/bicarbonate. Both base excess and bicarbonate are reduced indicating a metabolic acidosis.
50 mmol of 8.4% sodium bicarbonate IV is required: Not routinely recommended. Has several adverse effects, including exacerbating intracellular acidosis.
Pulseless electrical activity (PEA):
The first monitored rhythm is VF/VT in only 25% of cardiac arrests. Therefore PEA and asystole are relatively more common.
Is NOT usually the cardiac arrest rhythm in patients with severe hypovolaemia
Is characterised by evidence of ventricular activity on the ECG without detectable cardiac output
Amiodarone is only indicated in the treatment of cardiac arrest due to VF.
Hypovolaemia results in loss of venous return to the heart, with loss of cardiac output. This may be due to severe haemorrhage
When giving drugs during CPR:
The intracardiac route is not advocated. Peripheral venous access is quick, easy and safe.
Peak drug concentrations and circulation times are shorter when injected into a central vein, therefore this should be used.
Peripheral venous access is quicker, easier and safer than attempting central access and can be performed without stopping CPR
IO access is safe and effective for fluid resuscitation and delivery of all drugs used in resuscitation.
Adrenaline has both alpha and beta adrenergic effects.
IO access is safe and effective for fluid resuscitation and drug delivery during cardiac arrest.
Increases systemic vasoconstriction: This is due to the alpha adrenergic effect of adrenaline.
The alpha adrenergic effect increases coronary and cerebral perfusion pressures.
At a standard paper speed of 25 mm per second the ventricular rate is calculated by dividing the number of large squares between consecutive R waves by 60
Count the number of cardiac cycles that occur in 6 sec (30 large squares) and multiply by 10.
A ventricular tachycardia will always require immediate cardioversion
Cardioversion is required only if adverse features e.g. shock, syncope, heart failure.
A 55-year-old woman presents with a 1 hour history of crushing central chest pain, nausea and sweating. Her pulse rate is 38 beats min-1, BP 75 / 45 mmHg. The ECG monitor shows sinus bradycardia. You would recommend that:
Atropine is the first line treatment in a bradycardia with adverse features in an attempt to increase heart rate and cardiac output.
An adrenaline infusion 20-100 mcg min-1 may be required.
An adrenaline infusion may be required, the correct rate is 2-10 mcg min-1 IV.
Relief of pain is important and IV morphine should be titrated to control symptoms.
Oxygen by face mask should be given to achieve an arterial blood oxygen saturation (SpO2) of 94-98% (88-92% in the presence of COPD).This may require more than 24% initially.
Transmission of HIV during CPR has never been reported.
PPE should be used when the victim has a serious infection such as TB or SARS.
Gloves may provide limited protection from the electrical current, but no part of any person should make contact with the patient.
The ventilation bag can be left connected to the tracheal tube or supraglottic airway device. Alternatively disconnect and remove it at least 1 m from the patient.
Following successful resuscitation from VF cardiac arrest:
Oxygen should be titrated to maintain the arterial blood oxygen saturation (SpO2) at 94-98%. Not close to 100%
Ventilation should be adjusted to achieve normocarbia, PaCO2 4.7-6.0kPa.
Therapeutic hypothermia improves outcome in patients who remain in coma after ROSC: Although the evidence is based on studies of out-of-hospital VF arrests who remain in coma after ROSC, it should be considered for any mechanically ventilated patient admitted to ITU for organ support.
Absence of both pupillary light and corneal reflexes at 72 hours is a reliable predictor of outcome in comatose patients not treated with hypothermia: This is one of the few reliable prognostic factors.
Giving 8.4% sodium bicarbonate:
Intracellular acidosis: It does this by generating CO2 which diffuses intracellular.
Routine use is not recommended.
Raising the pH ie > 7.45 reduces the risk of arrhythmias in TCA overdose
It shifts the oxygen dissociation curve to the left, inhibiting release of oxygen to the tissues.
Primary percutaneous coronary intervention (PCI):
Is the preferred treatment for a patient with chest pain lasting more than 20 min and acute ST segment elevation in leads V4-V6 on their ECG
ST depression in V4-V6 is caused by a NSTEMI. PPCI is the preferred treatment for STEMI.
PPCI is the preferred treatment for STEMI, not unstable angina.
The sooner PPCI is commenced, the more effective it is. Longer delays are associated with higher mortality.
The correct management of an adult patient in ventricular fibrillation includes:
Adrenaline is given after the third shock and subsequently after alternate shocks (every 3-5 minutes).
Digoxin is not indicated in the treatment of VF. It is used in the treatment of atrial fibrillation.
Atropine is not indicated in the treatment of VF.
An initial biphasic shock at 150-200J. Subsequent shocks can be 150-360J biphasic.
Adrenaline is only given after the 3rd shock in VF. If ROSC is achieved before this adrenaline will not be required.
The initial dose of amiodarone for shock refractory ventricular fibrillation is 300 mg IV-This is given after the 3rd shock for patients in VF.
If the patient has adverse features, then cardioversion will be required. If stable treatment will depend on the QRS morphology.
Adenosine is effective in the treatment of paroxysmal supraventricular tachycardias
This can be tried after vagal manoeuvres if the rhythm is not atrial flutter.
If an organised rhythm is seen during a 2 min period of CPR, do not interrupt chest compressions to palpate a pulse unless the patient shows signs of life. Interruptions in chest compressions causes coronary perfusion pressure to decrease.
Compressions at 100-120/min are continued and the lungs are ventilated at 10 breaths/min without stopping compressions.
Agonal breathing is a sign of cardiac arrest, not a sign of life. Starting CPR on a patient with low cardiac output is unlikely to be harmful and may be beneficial.
In acute severe asthma:
Although the patient may be hypercapnic, cardiac arrest is secondary to hypoxia.
Oxygen should be given to achieve an SpO2 of 94-98%. This may need to be high-flow.
A PaCO2 of 5.3 kPa is NOT normal: Although this normal for a non-asthmatic patient, it is one of the indicators that the patient has life-threatening asthma and becoming exhausted. PaCO2 is normally low in an asthma attack due to hyperventilation.
Magnesium 2 g (8 mmol) IV may produce bronchodilatation: Magnesium is a bronchodilator and can be effective in these circumstances.
In a patient with suspected anaphylaxis:
Skin and mucosal changes are common features: They are often the first feature and present in over 80% of anaphylactic reactions.
Adrenaline is the most important drug for the treatment of an anaphylactic reaction. It should be given IM not IV.
Steroids are a second line drug and may help prevent or shorten protracted reactions. They have no effect in the acute situation.
There is no evidence to support the use of colloids over crystalloids. Consider colloids. They may also be the cause of anaphylaxis in a patient already receiving them at the time of the reaction.
A 65-year-old man with a 2-hour history of central chest pain develops a tachyarrhythmia that appears regular with a rate of approximately 180 beats min-1. BP <90
This patient has an adverse sign, hypotension, and therefore DC shock is indicated.
If he has no adverse signs and the QRS complex is < 0.12 sec, amiodarone 300 mg IV should be given.
If he has no adverse signs and the QRS complex is < 0.12 sec, adenosine 6 mg IV should be given.
If he has no adverse signs and the QRS complex is > 0.12 sec, amiodarone 300 mg IV should be given.
Hyperkalaemia is defined as a plasma conc > 5.5mmol l-1, severe hyperkalaemia is > 6.5mmol l-1.
Causes tall, peaked T waves and ST depression on the ECG
Renal failure is a common cause of hyperkalaemia.
The correct conc of calcium chloride is 10%, not 1%.
The only indication for not starting CPR in a patient is the presence of a valid advanced directive
There are other reasons for not starting CP, for example if it is considered futile, it does not have to be attempted.
Although patients have a right to refuse treatment, they cannot insist that resuscitation must be started in any circumstances.
Overall responsibility for decisions rests with the senior clinician in charge of the patient’s care
Although it is good practice to involve relatives, there is no legal requirement to involve relatives.
In second degree atrioventricular heart block:
Second degree block results in lack of QRS complexes after some P waves therefore always more P waves than QRS complexes
The P-R interval is always regular: There is progressive lengthening of the P-R interval in Type I block.
There is always a bradycardia: Not usually in type 1 block. More common in type II.
When it is Mobitz type II there is a risk of asystole: Mobitz type II is more likely to progress to complete block and asystole.
Higher defibrillation energies may be required in patients whose cardiac arrest has been caused by asthma. Hyperinflation increases thoracic impedance. Higher energies should be considered if initial ones fail.
The amplitude of the VF waveform is irrelevant in determining the need for a shock. FALSE: Fine VF is unlikely to be shocked successfully.
Pads should be placed at least 8cm from the ICD or alternatively in the AP position. FALSE to say: Self-adhesive pads must be placed in the antero-posterior position in a patient with an implantable cardioverter-defibrillator (ICD).
If the rhythm changes from asystole to VF, a shock should be given immediately: CPR should be continued until the end of the 2 min cycle and then a shock delivered.
Thrombolysis is contraindicated if the patient has had surgery within 3 months: Surgery within 3 weeks is an absolute contraindication.
PPCI is the most reliable method of reopening an artery and there is a lower risk of bleeding.
PaO2 26.6 kPa (FiO2 85%)
> 11 kPa on air
7.35 – 7.45
PaCO2 2.1 kPa
4.7 – 6.0 kPa
Bicarbonate 20.3 mmol l-1
22 – 26 mmol l-1
Base excess -4.6 mmol l-1
+2 to -2 mmol l-1
Breathing oxygen at high flow would provide an FiO2 of around 80%. We would expect the PaO2 to be 60-70 kPa.
The pH is increased indicating an alkalaemia.
The bicarbonate and base excess are reduced suggesting a mild metabolic acidosis.
The pH is increased indicating alkalaemia and this has been caused by the hypocapnia. There is no increase in bicarbonate or base excess to suggest this is metabolic in origin.
A 35-year-old lady is on the ward following a cholecystectomy. She complains of abdominal pain and appears pale and sweaty.
A respiratory rate of 30 breaths min-1 may be a sign of deterioration.
A high (>25 min-1) or increasing respiratory rate is a marker of illness and a warning that the patient may deteriorate suddenly.
Following successful resuscitation from a cardiac arrest:
The patient may be hyperkalaemic
The use of cardiac output monitoring doesnt improves outcome
Immediately after ROSC, there is a period (about 15 min) of cerebral hyperaemia.
Seizures or myoclonus occurs in about 10-40% of patients who achieve ROSC and remain comatose.
The QRS complex is less than 0.12 sec (3 small squares) and therefore originates above the ventricles. i.e. SVT
The interval between P waves is approximately 4.6 large squares giving a rate of 65 min-1.
If the patient is dyspnoeic and hypotensive, systolic blood pressure 80 mmHg, transvenous pacing is appropriate
This patient has complete heart block with broad complexes which puts them at risk of asystole.
The R-R interval is 12 large squares giving a ventricular rate of 25 min-1.
The P-R interval is 0.28 sec (7 small squares). This is prolonged and represents 1st degree heart block.
Atropine 0.5 mg IV up to a maximum of 3 mg is the initial treatment of a bradycardia in a patient with adverse features in an attempt to increase heart rate and cardiac output.
Adrenaline is contraindicated in the presence of this rhythm:
Adrenaline may be used to increase the rate in a patient with a pulse. If the patient is pulseless, this represents PEA and again, adrenaline would be appropriate treatment.