Background -It is known that automatic breathing is controlled by centres in the lower brain stem, whereas volitional breathing is controlled by the cerebral cortical centres. In hemiplegia, lesions above the brain stem result in paralysis of limb muscles. This study was performed to determine whether the diaphragm might also be affected in patients with hemiplegia. Methods -Studies were performed in six normal control subjects and in eight patients with complete hemiplegia caused by a lesion above the brain stem, all with no known chest disease. Full lung function tests were performed. Diaphragmatic excursion and inspired volume (VT) were measured simultaneously by M mode ultrasonography and respiratory airflow measurements. Recordings of diaphragmatic excursion were performed on each side separately during volitional and automatic breathing at a similar range of VT. Results -Lung function tests lay within the normal range in all the control subjects. In the hemiplegic patients mean (SD) vital capacity was 79 (18)% and residual volume was 123(30)% of predicted. Total lung capacity and functional residual capacity were in the normal range. In the control subjects no significant difference in diaphragmatic excursion was found between volitional and automatic breathing for the same range of inspired volume. By contrast, there was a significant decrease in diaphragmatic excursion during volitional breathing compared with automatic breathing on the affected side in four of the eight hemiplegic patients. Conclusions -In four of eight hemiplegic patients reduced diaphragmatic movement was present on the paralysed side during volitional inspiration when compared with automatic inspiration. The hemidiaphragm may be involved on the affected side in patients with hemiplegia.

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Background -Although real time ultrasonography has been used in the last decade to record diaphragmatic motion, the relation between diaphragmatic excursion and different inspired volumes (VT) has not been assessed by ultrasound. Methods -Ten normal subjects were studied in the supine posture. Diaphragmatic excursion and VT were assessed simultaneously by M mode ultrasonography and respiratory airflow measurements at different inspired volumes. Ultrasound recordings of the movement of the right hemidiaphragm were carried out in the longitudinal plane subcostally. The transducer was held in a fixed position by a frame, built especially to eliminate any artefactual movement caused by outward motion of the anterior abdominal wall on inspiration.Results -Mean (SD) maximal diaphragmatic excursion recorded was 6X0 (0.7) cm. Inspired volumes ranged from 15(5)% to 87(10)% of the subjects' inspiratory capacity. A linear relation between diaphragmatic excursion and VT was found in all subjects (r = 0.976-0.995).The regression line had a slope of (0.24) cm/l. This slope had no correlation with either the height (r = 0.007) or weight (r=0.143) of the subjects. In five subjects in whom diaphragmatic excursion could be recorded at volumes near total lung capacity, the relation between diaphragmatic excursion and VT became alinear at very high lung volumes. Conclusions -The relation between diaphragmatic excursion and VT was linear between 15(5)% and 87(10)% ofinspiratory capacity. Ultrasonography of the diaphragm is a simple technique that could be applied in the clinical investigation of patients with suspected abnormalities of diaphragmatic movement. (Thorax 1994;49:885-889) Until the last decade assessment of diaphragmatic movement relied traditionally on fluoroscopic measurements. The exposure to irradiation limits the duration of such studies.In addition, fixed reference points are difficult to establish because many structures within the field of view move with inspiration. Ultrasonography is a safe and accurate method which is currently used in cardiology with great reliability and reproducibility. This method has recently been used to assess normal movement of the diaphragm in subjects with no respiratory disease'2 and abnormal movement in patients with diaphragmatic pathology.3 The present study assesses the relation between diaphragmatic excursion and different inspired volumes with simultaneous ultrasonography and respiratory airflow measurements. Since inevitable movement of the transducer occurs as a result of abdominal movement during breathing if the probe is held by hand, it was necessary to build a special device to hold the transducer in a fixed position. Methods SUBJECTSStudies were performed on 10 healthy subjects (five men) with no history of respiratory disease. Their age was 31 (6) years, height 170 (9) cm, and weight 67 (11) kg. Nine of the subjects were either physiologists or technicians from the department of respiratory medicine and one was a naive subject. All gave their verbal informe...

Duplex Doppler ultrasound (DDU) was used to study the blood flow characteristics of the renal interlobar artery in 20 subjects with acute renal failure (ARF), 14 subjects with transient impairment of renal function and 23 control subjects with normal function. Renovascular resistance was assessed by pulsatility index (PI) and change in flow velocity by change in mean frequency shift (delta f). The 99% confidence intervals for PI in the three groups were 3.32-5.46, 1.58-2.34 and 0.99-1.33 respectively. Values for delta f were 0.2-0.38, 0.5-0.62 and 0.7-1.02 kHz respectively. Ten ARF patients recovered function, 99% confidence intervals for PI just prior to recovery were 0.9-1.48 and for delta f 0.52-1.02 kHz. There was increased renovascular resistance and reduced intrarenal blood flow velocity at the onset of ARF. These changes persisted during ARF; recovery of function occurred after they returned to normal. Similar, but less marked, changes were found in patients with a transient impairment of function.

This study describes a reliable and reproducible method of obtaining Doppler frequency shift waveforms from the uterine artery based on observations in 26 non-pregnant women. The waveforms werc detected easily but direct display of the vessel was inconsistent. The values of the pulsatility index calculated from the waveforms had a mean of 3.25 (SD 0-83). The standard error of the mean was 0.16 and based on this, the 95% reference range was 1.21 to 5.29. The stage of the menstrual cycle did not affect the pulsatility index nor was there any significant difference between subjects who were nulliparous and those who had had previous pregnancies. These results show that Doppler ultrasound can be applied to thc non-pregnant uterus and the data presented may be used as a baseline for the study of uterinc pathology.