A noninvasive method to determine the actual stomach contents of parturients may help to identify factors responsible for delayed gastric emptying as well as define the risk of aspiration of gastric contents in individual patients. Therefore, we tested the ability of ultrasound imaging to identify noninvasively the stomach contents of laboring and nonlaboring pregnant volunteers. A preliminary study demonstrated that the stomach contents could be identified by ultrasound in 20 healthy volunteers and in 34 parturients, not yet in active labor, scanned after consuming liquids or solid food. Next, 39 parturients in active labor were scanned at varying postprandial times. Sixteen parturients in active labor who had not eaten for 8-24 h still had food detected in the stomach. In fact, nearly two-thirds of the patients in active labor who were scanned had solid food present in the stomach independent of the interval between last oral intake and the ultrasound scan. The present study demonstrates that high-resolution ultrasonography is capable of noninvasively identifying the stomach contents of parturients. These results confirm the clinical impression that emptying of the stomach is delayed for many hours after the onset of labor.
To evaluate the accuracy of two non-invasive techniques for cardiac output (CO) measurement, we have measured CO simultaneously by thoracic electrical bioimpedance (TEB), pulsed Doppler ultrasound (DU) and standard thermodilution methods (TD) under different clinical conditions. Measurements were made in 10 patients: (I) during steady state anaesthesia with controlled IPPV ventilation (n = 131), spread over the entire ventilatory cycle; (II) during apnoea (n = 56); (III) during spontaneous breathing (n = 152) in the intensive care unit. Mean (SD) cardiac output values were: (I) COTD 3.5 (1.0) litre min-1, COTEB 3.4 (0.7) litre min-1, CODU 2.8 (0.7) litre min-1; (II) COTD 3.6 (0.6) litre min-1, COTEB 3.5 (0.4) litre min-1, CODU 2.9 (0.7) litre min-1; (III) COTD 7.7 (1.5) litre min-1, COTEB 7.6 (1.9) litre min-1, CODU 5.2 (1.4) litre min-1. The mean percentage deviation of TEB from TD ranged from -2.2% to 1.4% and that of DU from TD was from -16% to -32%. There were no statistically significant differences between TD and TEB, but TD and DU differed significantly during IPPV, apnoea and spontaneous ventilation (P < 0.0001).
Although the dependence of cerebral perfusion on blood pressure has been well studied, little data is available about the effect cardiac output has on cerebral flow velocity and autoregulation, particularly during acute stroke. To improve cerebral perfusion, we treated 10 patients who suffered from an acute ischemic stroke of the middle cerebral artery with a hypervolemic hemodilution combined with dopamine‐dobutamine. The influence of blood pressure and cardiac output on the blood flow velocity in the middle cerebral artery was measured using transcranial doppler sonography (TCD). Under the therapy, a dosage‐dependent increase of 12% in blood pressure (BP) and 53% increase in cardiac output was observed. There was a significant (p > 0.01) correlation between TCD‐mean flow velocity (Vm) and cardiac output (r = 0.33) as well as between Vm and blood pressure (r = 0.52) on the affected side. The unaffected side showed no correlation between Vm and cardiac output (r = 0.01), or between Vm and blood pressure (r = 0.03). Systolic flow velocity increased significantly in both hemispheres. As an expression of increasing cerebral vascular resistance, the pulsating index (PI) increased significantly (p > 0.01) in the affected hemisphere as well as in the unaffected hemisphere. This suggests that during acute stroke blood flow velocity and autoregulation in the affected vascular region depend not only on cerebral perfusion pressure but also on CO levels.
It is well known that blood pressure is elevated during acute stroke. Despite its importance for cerebral haemodynamics, cardiac output (CO) has been determined only in individual cases during acute stroke. We measured CO and blood pressure in patients with no history of heart disease who suffered from acute stroke (n = 30) and in a control group comparable with regard to age, gender and cardiac health (n = 30). CO, blood pressure and heart rate were significantly (P < 0.01) higher in the group of stroke patients than in the control group. There was a tendency for more time to have elapsed between the onset of symptoms and measurements, the higher the CO [b = 0.08 l/min per hour (-0.01; 0.17)]. Adjusted for age in a multiple regression model, the regression coefficient was significant (CO = 10.35 +0.094 x time -0.077 x age). The present study shows for the first time that patients with a healthy cardiovascular system who suffer from acute stroke have a higher CO than a group of comparable controls.
The cerebral representation of emotions has previously been investigated by the study of patients with local brain damage, experiments with selective stimulation of only one hemisphere, and more recently by imaging techniques such as positron-emission tomography or magnetic resonance imaging measuring local cerebral blood flow. We investigated the mean flow velocity (FVmean) in the middle cerebral artery (MCA) by transcranial Doppler sonography during emotional stimulation with video scenes in 24 healthy test persons. The videos consisted of an erotic scene and a violent scene shown in contrast to a calming scene. Blood pressure, heart rate, and breathing frequency were monitored continuously by noninvasive measurement. FVmean increased during the erotic scene to 108.5+/-11.9% (P < 0.05) of the baseline value in the right MCA and to 109.0+/-10.6% (n.s.) in the left MCA. During the violent scene FVmean reached 109.0+/-8.7% (P < 0.05) on the right side and 108.1+/-13.0% (n.s.) on the left side. The FVmean time course showed a close relationship to the video sequence. During scenes involving great tension FVmean showed a plateaulike state and peaked during sudden actions. Blood pressure, heart rate, and respiratory rate showed no significant changes. However, we observed a tendency towards lower heart rates (lowest value 94.5+/-13.6%) during the erotic scene and two peaks (103.2+/-13.3%, 104.8+/-16.8%) coinciding with sudden violent actions. The significant increase in FVmean in the right MCA supports the theory of a right hemisphere dominance for the processing of emotions.
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