Presentation on theme: "Presented by : Dr Rashmi Bhatt From: British Journal of Anaesthesia 2007."— Presentation transcript:
Presented by : Dr Rashmi Bhatt From: British Journal of Anaesthesia 2007
In his publication from 1920, the physician Eduard Schott from Cologne, Germany first described mechanical stimulation of the heart, which he performed, repeatedly and successfully, in a patient with recurrent Adam– Stokes attacks caused by complete heart block. Several case reports and case series have been published about this technique in the following decades, percussion (or fist) pacing seems to remain a ‘forgotten procedure’ in the management of symptomatic bradycardia or bradycardic circulatory arrest.
percussion pacing is still relatively unknown and does not represent a standard component of the therapeutic repertoire of most medical professionals. This is remarkable in as much as percussion pacing represents an instantly available and easy to perform procedure for temporary emergency pacing of the heart in symptomatic bradycardias, including bradycardic pulseless electrical activity (PEA) and CHB with ventricular asystole.
Case I: On postop day 6, after mechanical aortic valve replacement, a 78-yr-old female developed CHB. The intraoperatively inserted epicardial pacing wires had been removed shortly before. she presented with marked haemodynamic instability and recurrent loss of consciousness consistent with classic Adams–Stokes attacks. During insertion of a venous sheath and a transvenous electrical pacemaker wire, percussion pacing was performed as a temporary intervention. The patient instantly regained consciousness, and continuous plethysmographic reading of the pulse oximeter showed good electromechanical coupling.
CASE II: Ten days after an aortocoronary bypass operation, a 65-yr-old female presented for surgical revision of her sternum. After induction, the patient suddenly developed CHB associated with marked haemodynamic instability. percussion pacing was initiated, resulting in rapid restoration of an adequate mean arterial pressure. CASE III: a 3-yr-old girl was undergoing percutaneous closure of a large secundum ASD under GA. During the procedure, the occluder slipped off the septal rim and impacted in the right ventricular outflow tract. During a successful attempt to retrieve the occluder with a snare catheter, the septal leaflet of the tricuspid valve was injured, with subsequent CHB and ventricular asystole. Percussion pacing was started instantly and A good peripheral pulse was palpable and visible in a continuous plethysmography signal.
In a 55-yr-old woman with CHB, Chan and colleagues compared the three different modes of emergency cardiac stimulation: percussion pacing, transcutaneous, and transvenous electrical pacing. Ventricular stroke volumes calculated with the use of a previously inserted pulmonary artery catheter, were comparable for all three techniques. Whereas chest compressions produce compressions of the heart with passive expulsion of blood, mechanical stimulation in percussion pacing generates an almost physiological situation with electrical impulses followed by myocardial contractions. ‘Percussion pacing’ and ‘fist pacing’ are used synonymously. Furthermore, some authors do not clearly differentiate between ‘percussion (fist) pacing’ and ‘precordial’, or ‘chest thumping’.
Percussion pacing is based on the physical phenomenon of energy transformation; mechanical energy applied to viable myocardium triggers an electrical impulse, after an all-or-none principle. Precordial thumping, which is often confused with percussion pacing, produces a premature ventricular beat (PVB), capable of terminating early ventricular tachycardia, or ventricular fibrillation. In percussion pacing, rhythmically applied mechanical stimuli produce serial PVBs (electrical coupling), thus generating consecutive contractions of the myocardium with ventricular ejection (mechanical coupling).
In some case reports, one single fist blow terminated symptomatic bradycardia. However, most authors and also the European Resuscitation Council (ERC) recommend serial blows with a rate of approximately 50–70/min. Compared with precordial thumping, percussion pacing is performed with less force. To estimate the required mechanical energy, it is recommended to let the ulnar side of the fist fall from a height of approximately 20–30 cm above the chest, on left lower sternal edge. Because of its larger force, precordial thumps intended to terminate tachyarrhythmias are applied to the mid sternum, whereas for percussion pacing the lower left sternal edge is recommended, presumably above the right ventricle.
increase in right ventricular pressure of at least 15–20 mm Hg is necessary to generate an electrical impulse in the myocardium. the efficacy of percussion pacing must be controlled and reconfirmed continuously. Mechanical artifacts may render it difficult to identify percussion-generated QRS complexes (i.e. electrical coupling), if the ECG leads are attached to the chest or shoulders. Hence, it seems useful to attach the leads to the arms and legs, similar to the practice in cardiac catheterization. A palpable central or peripheral pulse confirms mechanical coupling, often visible on the pulse oximeter in a reliable plethysmographic reading. an indwelling arterial catheter or a pulmonary artery catheter may be available for reliable confirmation of the presence of a pulse with sufficient CO. Regaining of consciousness in patients suffering Adam–Stokes attacks is also regarded as a good clinical sign of restitution.
Percussion pacing is generally indicated in all haemodynamically unstable bradyarrhythmias, in particular in CHB with or without ventricular escape rhythm (‘P wave asystole’). the presence of atrial activity is regarded as a prerequisite for successful stimulation. Instantly started percussion pacing can bridge the time it takes to establish transcutaneous or transvenous electrical pacing. In many patients with bradycardic circulatory arrest (PEA), percussion pacing can replace chest compressions until pharmacological or electrical intervention shows its effect. Particularly, in post- cardiac surgical patients, the avoidance of chest compressions may prevent the serious complication of an unstable sternum.
If no cardiac stimulation can be achieved in bradycardic PEA, cardiopulmonary resuscitation (CPR) must be started immediately. Whereas there is a paucity of evidence on percussion pacing, there exist numerous animal studies, case reports, and case series to report on its efficacy. However, partly because of the ERC’s recent incorporation of percussion pacing into their 2006 ALS manual, it is likely that this technique will receive more widespread publicity and clinical use.