Cardiopulmonary resuscitation Flashcards
CPR is a set of procedures and pharmacological interventions designed to
increase oxygen delivery to the heart and the brain during cardiac arrest.
The ultimate goal of CPR is to
restore spontaneous, effective cardiac and respiratory efforts.
Cardiopulmonary arrest (CPA) is present when
there is a sudden and unexpected cessation of heart function and/or when cardiac pumping failure results in loss of consciousness and eventual respiratory arrest.
Changes observed before Cardiopulmonary arrest
¡ Hypothermia
¡ Bradycardia
¡ Hypotension
¡ Dilated unresponsive pupils (!)
¡ Gasping breathing
¡ Agonal breaths
¡ Blueish mucous membranes
NB! Mucous membranes color may remain normal for several minutes after arrest.
Definitive clinical signs of CPA: (4)
loss of consciousness,
absence of spontaneous ventilation, absence of heart sounds on auscultation, absence of palpable pulses
CPR induces spontaneous cardiac rhythm recovery in what % of cases?
34% of cases
In small animals, only 4-12% of patients who have experienced cardiac arrest survive.
CPR is effective and has a good chance of survival if the cardiac arrest occurred as a complication of anesthesia.
Resuscitation should continue for how long?
Resuscitation should continue for at least 20 minutes but not longer than 30 minutes!
Describe Circulation-portion of CPR.
restoration of circulation
¡ Rapid auscultation of the heart with a stethoscope and palpation of the pulse.
¡ If there are no heart sounds - start chest compressions.
¡ Chest compressions at a rate of 100 - 120 times per minute.
¡ The diameter of the chest is compressed by 35 - 50% (maximum 25% in the dorsal position).
¡ After compression, the chest must restore its full diameter - otherwise diastolic filling of the heart will not occur.
¡ Compressions are performed in 2-min cycles.
When resuscitating cats and small dogs - use what technique for compressions?
two thumbs, one thumb or palm technique.
Describe Restoring airway patency -portion of CPR.
¡ Ensure airway patency of the animal by endotracheal intubation.
¡ Local anesthesia of the vocal cords with lidocaine in cats!
¡ Vocal cord spasm is possible 3-4 minutes after cardiac arrest.
¡ Connect the Ambu bag to the endotracheal tube.
¡ Give two long breaths
¡ Under normal circumstances, the correct placement of the endotracheal tube can be checked with capnograph, but in case of cardiac arrest, ETCO2 is 0 or close to zero.
¡ If placement of the endotracheal tube is difficult or impossible – consider emergency tracheotomy.
¡ In non-intubated animals, a well-fitting face mask (rubber rimmed mask, etc.) should be preferred for performing manual
ventilation.
Describe the ventilation-portion of CPR.
¡ If the animal is attached to an anesthesia machine, make sure that the anesthetic vaporizer is turned off.
¡ Quickly turn the animal on its right side
¡ Start ventilation of the lungs with 100% oxygen.
¡ Ventilation is started with two breaths and then it is assessed whether spontaneous breathing has returned or not.
¡ If spontaneous breathing has not returned within 7 – 10 seconds, start ventilating the animal with an Ambu bag at a rate of 10 – 12 times per minute.
¡ Cooling the animal’s head area with ice packs reduces the likelihood of anaerobic glycolysis of the brain.
¡ If the initial resuscitation efforts are unsuccessful (no heartbeat, no change in
mucous membrane color), something needs to be changed: (4)
¡ Strengthening compressions
¡ Increasing compression speed
¡ Increasing compression duration (systole)
¡ Changing the position of the veterinarian’s hands
Drugs used in resuscitation (4)
¡ Epinephrine (adrenaline)
¡ Atropine
¡ Lidocaine
¡ Amiodarone (antiarrhythmic)
Describe Epinephrine
¡ Agonist of both a1- and b1,2-drenoceptors
¡ Effects of stimulation of b1-drenoceptors:
- ¡ Increase in heart rate
- ¡ Increase in contractility
- ¡ However, increase in myocardial oxygen
consumption as well.
¡ Effects of stimulation of b2-drenoceptors:
- ¡ Relaxation of bronchial smooth muscles – breathing becomes easier.
¡ Effects of stimulation of a1-adrenoceptors:
- ¡ Vasoconstriction (centralization of blood)
Epinephrine low dose?
High dose?
¡ Low dose (0.01 mg/kg IV)
- 1 ml of 1:1000 adrenaline is diluted with 9 ml of NaCl 0.9%, resulting in a 1:10000 solution. Dose 1 ml per 10 kg.
¡ High dose (0.1 mg/kg IV) - no longer recommended according to new guidelines!
¡ Pure adrenaline (1:1000) IV: 1 ml per 10 kg
¡ High dose use is associated with extremely high oxygen consumption
¡ High dose use is associated with an increased likelihood of recurrent ventricular fibrillation
¡ Studies show that high dose use of epinephrine reduces survival rates
Lidocaine Local anesthetic with antiarrhythmic activity Effective in (2)
¡ Ventricular tachycardia
¡ Ventricular fibrillation
Dose: 2 mg/kg IV in dogs and 0.5 mg/kg IV in cats.
The blind intracardiac route is associated with
a number of potential problems and must be avoided.
¡ Blind IC injections may be associated with lung laceration, coronary artery laceration, heart laceration.
¡ IC administration of epinephrine may cause refractory ventricular fibrillation.
¡ IC injections requires discontinuing the compressions. It is technically difficult because there is no apex beat.
¡ Doesn’t increase the chance of survival
¡ Only in the case of open heart
What are the 2 rhythms depicted?
Top: Ventricular fibrillation
Bottom: Ventricular tachycardia
CPR formula / min
Compressions 100-120 times/min
Manual ventilation 10 - 12 times/min
