Loss of consciousness on turning the patient

• Published in: BMJ 2010-08, Vol.341 (aug11 1), p.c3542-c3542
• Main Authors: van Boxel, G I, Goodman, A J, Green, J, Orme, R M
• Format: Article
• Language: English
• Subjects: Aged, 80 and over; Anesthesiology; Biliary Fistula - complications; Catheters; Cerebral Arteries - diagnostic imaging; Cholangiopancreatography, Endoscopic Retrograde - adverse effects; Computed tomography; Consciousness; Coronary Vessels; Echocardiography; EKG; Electrocardiography; Embolism; Embolism, Air - diagnostic imaging; Embolism, Air - etiology; Embolisms; Endoscopy; Foramen Ovale, Patent - complications; Heart attacks; Heart diseases; Humans; Hypertension; Hypertonicity; Intensive care; Lungs; Male; Medical diagnosis; Myocardial Infarction - etiology; Oxygen therapy; Pressure; Prone Position - physiology; Pulmonary arteries; Reflexes; Supine Position - physiology; Tomography, X-Ray Computed; Unconsciousness - etiology; Vascular Fistula - complications; Veins & arteries
• ISSN: 0959-8138; 1468-5833; 1756-1833
• DOI: 10.1136/bmj.c3542

Generalised hypertonicity with brisk reflexes and upgoing planters were noted at this stage. Because he was haemodynamically stable, computed tomography of the head was performed without delay to rule out an acute intracranial bleed (figs 1 and 2 ). [...]if the volume of air is large (>100 ml) it can cause cardiac arrest through complete right heart failure or massive pulmonary embolism, 6 7 or by paradoxical right to left shunting. [...]an abnormality, in the form of a patent foramen ovale, is present in 27% of the population. 8 Under normal physiological conditions the pressure in the left side of the heart is greater than that of the right so right to left shunting cannot occur. Under physiologically abnormal conditions-for example, when a large venous air embolism in the pulmonary trunk raises the pressure in the right side of the heart above that of the left-a right to left shunt may allow air to pass to the arterial side causing an arterial air embolism. A normal transthoracic echogram does not preclude the presence of a small patent foramen ovale-this requires a bubble contrast study to be performed to identify the passage of air between the right and left atria upon release of a Vasalva manoeuvre. Even under these conditions this technique has a sensitivity of 63% compared with the gold standard-transoesophageal echocardiography. 9 The second proposed mechanism involves a failure of the lungs to reabsorb air when the volume of air is too large. Short answer The changes on electrocardiography...