Cardiac Surgery
Lec: 4Cardiac Trauma
May be either :-
1.Blunt Trauma
2.Pentrating Trauma:- Which is either due to:
a.Stab wound b.gun shot c.iatrogenic e.g by chest tube.
Clinical Presentation depends on:
1.Site of injury 2.mode of injury 3.associated injuries
The Right ventricle is mostly involved by penetrating injuries in 42% of cases because it occupies the largest percent of the anterior surface area of heart followed by Left ventricle in 32% of cases and Right atrium in 15% of cases, Factor affect Mortality from penetrating injuries may be due to
1.Coronary artery injury
2.multiple chamber injury
3.Isolated left side injury
4.commonuted tear of single chamber
5.Isolated right side chamber injury
6.Tangential injurywhich does not penetrate the endocardium
Clinical Presentation
A.Temponade:- occur in 80% of cases of stab wound injuries and 20% of gunshot injuries.
B.Heamorrhagic shock occur in 20% of stab wound injuries and 80% of gun shot injuries.
Cardiac Temponad :-
Occur due to small tears in the pericardium and myocardium, here little or transient haemorrhage will be sealed by contraction of myocardial muscles, the collection of 150 ml. Of blood inside the pericardium will press on the heart and leads to classical signs of Becks Tride which are:
1.Hypotention 2.Distended neck veins 3.Muffled heart sounds
Other features may be present like tachycardia ,shortness of breath, pulses paradoxus.
Heamorrhagic shock:-
Occurs due to large tear in the heart and pericardium which leads to :-
1.sever bleeding 2.sever hypotention and bradycardia 3.flat neck veins 4.high mortality
Investigations:-
Chest Film:- In temponade it is of no benefit as it is an acute event there will be no enough time for the pericardium to distend ;while in haemorrhagic shock we may see haziness and irregularity of cardiac boarder but the patient may not live long enough to chest film
Echo :- requires cooperative patient and well trained personal and associated with 5% false negative rate.
Pericardiocentesis :- must be done with great care and better to be guided by echo and paitent must afford pain ; in 15% of cases the blood may be clotted.
Subxyphoid pericardial window:- can be done under local anaesthesia and when blood found it is evacuated easily and the incision can be converted to median sternotomy to repair the cardiac injury.
Management :-
1. Secure the air ways, if the patient is not breathing spontaneously endotracheal tube must be inserted and oxygen must be delivered by umbo back or ventilator.
2. Establish 2 or 3 I.V lines to deliver crystalloid and/ or colloid, in Temponade this is of diagnostic value since it improve general condition of the patient transiently.
3. Emergency room operation is indicated in the following condition
Low Blood Pressure or Agonal breathing.
b. Rapid deterioration.
Patient can not be stabilized by usual resuscitative measures.
Strong suspect of cardiac injury.
The operation is carried out either by Median Sternotomy or Left Anterior Thoracotomy.
Methods of repair of cardiac injury.
1.Atrial injury: put a side clamp and suture the tear.
2.Large vessel injury : repaired like atrial injury.
3. Small hole in the ventricle :suture with pledgete
4. injury beside coronary artery: suture with pledgete beneath the coronary artery
5.Coronary artery injury: if small ligate the artery ,if large ligate and do coronary bypass graft.
6.Intracardiac injury: can be manged later on unless it is sever.
Blunt Cardiac Trauma:-Usually produce cardiac contusion which may produce heart block, arrhythmia and decrease contractility sometimes damage to atrial septum or ventricular septum may occur or damage to valve may occur.
Investigation :-
1.Cardiac enzmes usually elevated
2. ECG shows rhythm disturbance
3.Echo showsabnormal contractility
Management :-
Simple injury usually self limited and improve spontenously.
Sever injuryleads to poor out comelike cardiac arrest.
Cardiopulmonary resuscitation:-Measures done to manage person sustain cardiopulmonary arrest.cardiac arrest may be due to arrhythmia which may be due to
a. Coronary artery diseases b. Anoxia C.electrolyte disturbance d. Drug toxicity.
Diagnosis is done by confirmation of
1.unconsciousness
2.abscence of central pulse and breathing for 15 seconds
Cardiac arrest leads to hypoxia and anerobic metabolism
Management:-
1.Secure air ways and breathing.
2. establish I.V lines
3.Cardiac massage either closed chest massage or open cardiac massage.
4. ECG monitoring
5. drugs like adrenaline, xylocain, NaHCO3, insulin+glucose for hyperkalemia
6. Temporary transvenous or extracardiac pacemaker.