Annals of cardiac anaesthesia
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Two features of off-pump coronary artery bypass (OPCAB) can lead to hemodynamic instability: transient occlusion of coronary arteries during distal anastomosis construction and displacement of the heart to provide access to distal coronary arteries. The position of the heart during OPCAB trans-esophageal echocardiography (TEE) can often provide an indication as to how much compression of the right or left ventricle has occurred. If either chamber is not filling, repositioning of the heart will be necessary. ⋯ This, along with distal anastomosis causing transient occlusion of coronary arteries, may cause transient hypotension with increased filling pressures. TEE is more helpful in this scenario. In these patients, TEE helps differentiate between cardiac dysfunction and secondary to myocardial ischemia in which regional wall motion abnormalities will be present from a much more common scenario where the increase in filling pressure is secondary to extra cardiac compression and provides the ability to detect mitral regurgitation (MR) with a color-flow Doppler, as well as assess right heart function.
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Review Meta Analysis
Halogenated anaesthetics and cardiac protection in cardiac and non-cardiac anaesthesia.
Volatile anaesthetic agents have direct protective properties against ischemic myocardial damage. The implementation of these properties during clinical anaesthesia can provide an additional tool in the treatment or prevention, or both, of ischemic cardiac dysfunction in the perioperative period. ⋯ The American College of Cardiology/American Heart Association Guidelines recommend volatile anaesthetic agents during non-cardiac surgery for the maintenance of general anaesthesia in patients at risk for myocardial infarction. Nonetheless, evidence in non-coronary surgical settings is contradictory and will be reviewed in this paper together with the mechanisms of cardiac protection by volatile agents.
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Cardiac allotransplantation has, over the years, become the established therapeutic modality for patients with end-stage heart failure. Significant advances in immunosuppressive therapy have dramatically improved the outcome of heart transplantation over the past four decades. This review will focus on the anaesthetic challenges involved in the perioperative management of these complex patients as well as some of the proposed alternatives to transplantation.
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There have been great advancements in cardiac surgery over the last two decades; the widespread use of off-pump aortocoronary bypass surgery, minimally invasive cardiac surgery, and robotic surgery have also changed the face of cardiac anaesthesia. The concept of "Fast-track anaesthesia" demands the use of nondepolarising neuromuscular blocking drugs with short duration of action, combining the ability to provide (if necessary) sufficiently profound neuromuscular blockade during surgery and immediate re-establishment of normal neuromuscular transmission at the end of surgery. Postoperative residual muscle paralysis is one of the major hurdles for immediate or early extubation after cardiac surgery. ⋯ Kinemyography and acceleromyography are the most important currently used neuromuscular monitoring methods. Whereas monitoring at the adductor pollicis muscle is appropriate at the end of surgery, monitoring of the corrugator supercilii muscle better reflects neuromuscular blockade at more central, profound muscles, such as the diaphragm, larynx, or thoraco-abdominal muscles. In conclusion, cisatracurium or rocuronium is recommended for neuromuscular blockade in modern cardiac surgery.
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Minimally invasive and non-invasive methods of estimation of cardiac output (CO) were developed to overcome the limitations of invasive nature of pulmonary artery catheterization (PAC) and direct Fick method used for the measurement of stroke volume (SV). The important minimally invasive techniques available are: oesophageal Doppler monitoring (ODM), the derivative Fick method (using partial carbon dioxide (CO2 ) breathing), transpulmonary thermodilution, lithium indicator dilution, pulse contour and pulse power analysis. Impedance cardiography is probably the only non-invasive technique in true sense. ⋯ The physical and the physiological aspects underlying the pulse contour and pulse power analyses, various pulse contour techniques, their development, advantages and limitations are also covered. The principle of thoracic bioimpedance along with computation of CO from changes in thoracic impedance is explained. The purpose of the review is to help us minimize the dogmatic nature of practice favouring one technique or the other.