CURRENT Essentials of Critical Care.pdf

128 Current Essentials of Critical CareSyncope■ Essentials of Diagnosis• Transient loss of consciousness and postural tone with promptrecovery• Pallor and generalized perspiration prior to event• Cardiac syncope: chest discomfort, dyspnea, palpitations• Vasovagal syncope: prodrome of light-headedness, diaphoresis,nausea, “aura”• Bradycardia and hypotension not always identified• Monitor ECG and rhythm strip• Echocardiogram to identify structural heart disease• Tilt-table testing to evaluate vasovagal symptoms■ Differential Diagnosis• Cardiovascular: arrhythmias, outflow tract obstruction• Pulmonary vascular disease: pulmonary embolism, pulmonaryhypertension• Vasovagal syndrome and situational syncope: cough, micturition,pain• Postural hypotension and autonomic dysfunction• Neurologic: cerebrovascular accidents, vertebrobasilar insufficiency,seizures• Metabolic derangements: hypoglycemia• Hypoxemia• Hysterical fainting■ Treatment• Identify and correct underlying etiology• When patient is unconscious, position horizontally and secureairway• In vasovagal syncope effective prophylaxis can be achievedwith beta-blockers; theophylline, scopolamine, disopyramide,ephedrine, support stockings tried with varying success• Pacemakers: adjunct in management of cardioinhibitory responsesseen in vasovagal syndromes; indicated in bradyarrhythmias• Fludrocortisone helpful in autonomic dysfunction• Electrophysiology studies and implantable defibrillators can beconsidered in tachyarrhythmias especially ventricular in origin• Advise against driving■ PearlIn tilt-table testing for vasovagal syndromes, vasodepressor and cardioinhibitoryresponses may be seen but are diagnostic only when associatedwith symptoms.ReferenceKapoor WN et al: Current evaluation and management of syncope. Circulation2002;106:1606. [PMID: 12270849]