principles of transoesophageal echocardiography—practical aspects 21 Fig. 1.22 Standardized subcostal short-axis view at the mitral valve level during diastole (a) and systole (b), as well as the corresponding colour-coded images during diastole (c) and systole (d). Standardized subcostal short-axis view at the mid-papillary level during diastole (e) and systole (f), as well as the corresponding colour-coded images during diastole (g) and systole (h). Additional comments in the text. Fig. 1.23 The standardized subcostal short-axis view through the pulmonary valve and the pulmonary trunk at diastole (a) and systole (b). The corresponding colourcoded views are displayed in (c) and (d). In (e) the pulsed wave Doppler spectrum of the right ventricular outflow tract is shown. Additional comments in the text.
22 chapter 1 conventional echocardiography—basic principles Fig. 1.24 The subcostal longitudinal view of the inferior caval vein during expiration (a) and inspiration (b). Additional comments in the text. Fig. 1.25 The suprasternal view of the aortic arch using grey scale mode (a) and colour-coded imaging (b). Additional comments in the text. system. The patient should have an empty stomach, dental fixtures should be removed and a bite guard should be used to protect the shaft of the probe. A local oropharyngeal anaesthesia with lidocaine spray is often sufficient for intubation of the oesophagus. If additional sedation is needed, intravenous administration of midazolam (0.075 mg/kg) can be added in stable patients. It is obvious that lower sedation doses should be used in patients with severe heart failure or in patients with other compromising diseases. The transoesophageal echocardiography is normally performed in the left lateral position. During intubation of the probe, the tip of the probe has to be unlocked, regarding flexion and extension, to avoid injury to the oesophageal wall. After the examination the probe has to be disinfected as well as inspected for damage according to the international guidelines. The insertion of the probe is the most uncomfortable moment for the awake or slightly sedated patient. Assistance during the intubation is helpful to enable the most convenient mode of introduction of the probe ( Figs 1.26–1.27). The user-operated actuator should be held by the assistant directly above the patient in the vertical direction with the shaft leading downwards ( Fig. 1.26a–b). Then, the shaft is touched by the operator with the right hand at the distal shaft near the movable tip ( Fig. 1.26b–c). The distal ending of the unlocked probe is curved and adapted to the curvature of the oropharynx ( Fig. 1.26c). The left hand of the operator is free for manipulating the tip of the probe during introduction to the oral cavity. The advantage of this setting is that by pushing the probe forward into the oesophagus, the tip, as well as the shaft, of the probe will follow the natural course of the upper pharyngeal isthmus without inducing unnecessary forces to the wall of the pharynx and the upper oesophagus. The fingers of the left hand will guide the tip of the probe. If the bite guard has to be positioned between the teeth during insertion, the second finger should be laid across the tongue. Then, the probe can be fixed to the back of the pharynx, but positioned at the ridge in the middle of the tongue for