Chapter 2 - Cardiac Flashcards
VT
Treatment
- Pulseless = emergency defib
- Pulse present = anti- arrhymic and may consider cardioversion
Looks like
- Tomb stones
VF
Description
- Multiple areas within the ventricles display marked variation in depolarisation and repolarisation. Since there is no organised ventricular depolarization, the ventricles do not contract as a unit.
- There is no cardiac output – this is the most common mechanism of cardiac arrest resulting from myocardial ischemia or infarction.
Treatment
- defib
Coarse VF vs Fine VF
Coarse VF - indicates recent onset and can be reversed by defib promptly.
Fine VF - indicates that there has been a considerable time since the collapse, heading towards asystole.
Torsades de Pointes
Description
- A form of VT in which the QRS complexes appears to be constantly changing in amplitude.
- This is due to, LONG QT syndrome, drug intoxication or an idiosyncratic reaction to antiarrhythmic agents such as quinidine or procainamide.
- Hypokalaemia, hypomagnesemia, phenothiazine overdoses and bradycardia can precipitate this also.
Treatment
- Pulseless: emergency defib
- Pulse present: Magnesium sulphate, isoprenaline and pacing.
PEA
Check pulse as can look like sinus.
Treatment
- BLS
- Correct reversable causes
TYPES OF P.E.A
1. Narrow complex – Associated with profound hypovolemia, practically multi-trauma pt.
2. Broad complex – observed in cardiac arrests, associated with massive MI, hypoxic and severe hyperkalemia.
** PEA following a significant MI usually signifies a terminal event e.g., tamponade
Asystole
Description
- Ventricular asystole represents the total absence of ventricular electrical activity. May occur as the primary event of a cardiac arrest of may follow VF / PEA.
Treatment
- BLS
- Adrenaline
Precordial Thump
A precordial thump may be administered when VT/VF is confirmed on monitor and in a witnessed arrest when a defib is not immediately available.
Using the ulna edge of a tightly clenched first, the hand is raised approx. 20cm above the patient’s chest then a sharp blow is delivered to the lower portion of the sternum.
- More effective in VT than VF.
Defib - anatomy
- Therapeutic application of an electric shock to terminate an arrhinia and attempt to restore normal sinus rhythm.
- A single brief electric shock is applied to the heart to completely depolarise the myocardium thus allowing uniform repolarisation of the myocardial cells.
- The sinus node then resumes as the dominant pacemaker.
Electrode (paddle) placement.
1 x right parasternal area over the second intercostal space
1 x left side of the chest in the mid-axillary line in the sixth intercoastal space
- Can be used for up to 150 shocks
- Can remain on pt. for 24 hours.
Transthoracic resistance
Impendence is resistance to the flow of electrical current and is measured in ohms. Resistance must be overcome for successful cardiac defibrillation.
- Transthoracic resistance is the resistance to the current flow imposed by the chest wall, lungs and the myocardium.
- Impedance is influenced by the contact between the electrode and the skin.
** Resistance is decreased when lungs are empty so defb. Is best carried out on expiration.
Hypoxemia
Hypoxemia can be defined as an abnormal deficiently of oxygen concentration in arterial blood supplying the brain and to the vital organs.
- It is diagnosed by cyanosis, Sp02 <75% and Pa02 <70 mmHg.
- The tissues most sensitive to hypoxemia; brain, heart, pulmonary vessels, and liver.
COMMON CAUSE:
Due to respiratory failure in a pre-arrest or arrest situation.
TREATMENT:
Exclusion of mechanical causes of obstruction and corrective measures e.g., high flow concentration oxygen. Securing the airway with an LMA or ETT.
MINAMISE RISK:
1. Ventilate lungs to 100% oxygen
2. Adequate chests rise and fall
3. Bilateral breath sounds
4. ETT – not misplaced e.g., bronchus or oesophagus
5. Ensure patent and secure airway e.g., ETT, LMA.
Hypovolaemia
Hypovolemia is an abnormally low circulating blood volume (blood or plasma).
COMMON CAUSE:
Caused by obvious trauma / blood loss, multiple fractures – particularly pelvic and long bone fractures. Dehydration, fluid shift or sepsis.
TREATMENT:
IV Fluids – colloids/crystalloids and or blood products and correcting the source of blood loss.
MANAGEMENT:
1. Rapid restoration of intravascular volume with fluid
2. Urgent surgery.
3. In the initial stages in resus there are no advantages to using colloids; use saline or CSL (CSL is preferred in trauma).
a. Avoid dextrose as it is redistributed away from the intravascular space and rapidly causes hyperglycaemia which worsens neuro outcomes.
- Hyper/Hypokalaemia & metabolic disorders
This covers the reversable causes of abnormal <> electrolyte levels.
- Most common; K + Calcium
- Hypothermia/Hyperthermia
Hypothermia – low core body temperature, <30*c
COMMON CAUSES:
Exposure, near drowning, prolonged operative period.
TREATMENT:
- Slow rewarming procedures. E.g., Bair hugger, warm IV fluids, heated ventilator
NOTE
- Can not defib if pt. core body temp is equal or > 30* c. Continue CPR.
- Adrenaline reduced its effects in severely hypothermic patients and therefore the time before amin is every 8 minutes.
- Tension Pneumothorax
Tension pneumothorax develops when an air leak into the pleural space acts as a one-way valve. Air moves into the pleural space on inspiration but cannot escape on expiration. This results in a rapid increase in intrapleural pressure and collapse of the affected lung to the opposite side, displacement of the mediastinum to the opposite side and compression of the heart and major blood vessels.
Cardiac arrest can occur if not promptly relieved.
INDICATIONS:
- Tracheal deviation away from the affected side
- Tymoany percussion
- Absent breath sounds on auscultation
TREATMENT:
Insertion of a large bore needle into the 2nd intercostal space, midclavicular line on the affected side. Immediate prep for insertion and intercoastal drain is required
