Breathing patterns. 1. Normal subjects.

Ventilatory monitoring devices that require mouthpiece breathing produce a rise in tidal volume (VT), a fall in frequency (f) and alterations in periodicity and variability of breathing components. Together with the introduction of the respiratory inductive plethysmograph, a reliable noninvasive monitoring device of ventilation, major advances have taken place in understanding the significance of the components of the breathing pattern. We measured the breathing pattern of normal subjects utilizing respiratory inductive plethysmography and continuously processed these data with a microprocessor system. The mean values of the breathing pattern components in normal subjects were not affected by age, but the rhythmicity was more irregular in the elderly. The values of breathing pattern components obtained noninvasively by respiratory inductive plethysmography in normal subjects are fairly predictable in limits similar to other tests of pulmonary function.

Breathing patterns. 2. Diseased subjects.

We measured the breathing pattern of normal subjects, asymptomatic smokers, asymptomatic and symptomatic asthmatic patients, and patients with chronic obstructive pulmonary disease, restrictive lung disease, primary pulmonary hypertension and anxiety state utilizing respiratory inductive plethysmography. Respiratory rate was increased above the normal in smokers and in patients with COPD, restrictive lung disease and pulmonary hypertension, but remained normal in asthmatic patients. Inspiratory times (T1) of one second or less often occurred in patients with COPD, restrictive lung disease, and pulmonary hypertension. Smokers and patients with symptomatic asthma, COPD, restrictive lung disease and pulmonary hypertension showed heightened respiratory center drive as reflected by elevated mean inspiratory flow (VT/TI). Fractional inspiratory time was reduced to a variable extent in smokers, symptomatic asthmatic patients and patients with COPD, and was a weak indicator of airways obstruction. Patients with COPD often had major fluctuations of expiratory timing, periodic fluctuations of end-expiratory level, and asynchrony between rib cage and abdominal movements. Chronic anxiety was characterized by frequent sighs; episodic rapid rates alternating with apneas were less common. We conclude that analysis of breathing patterns provides diagnostic discrimination among normal subjects and disease states.

The validation of duplex scanning and continuous wave Doppler imaging: a comparison with conventional angiography.

Colour-coded continuous wave (CW) Doppler imaging and duplex scanning have been assessed prospectively in comparison with biplanar angiography for their accuracy in detecting significant arterial disease in the extracranial circulation. Of 96 comparisons with biplanar angiography, the sensitivity of Doppler imaging was 90% and specificity 98% in the detection of greater than 50% internal carotid stenosis and 86 and 100%, respectively, in the diagnosis of internal carotid occlusion. Of 85 comparisons with biplanar angiography, the sensitivity of duplex scanning was 93% and specificity 98% in the detection of greater than 50% internal carotid stenosis and 92 and 100%, respectively, in the diagnosis of internal carotid occlusion. The value of the peak systolic Doppler shift frequency of the internal carotid artery signal has proved to be the most reliable indicator of greater than 50% stenosis and is utilised in conjunction with a periorbital examination. It is concluded that both Doppler imaging and duplex scanning are effective screening techniques for the presence of significant (greater than 50%) internal carotid artery disease.

The accuracy of duplex scanning in the evaluation of early carotid disease.

The accuracy of duplex scanning in 69 comparisons with biplanar angiography in the detection of early carotid disease has been assessed. The various criteria reported for the categorisation of less than 50% disease have been critically analysed. As part of the study, 50 internal carotid arteries of 25 young, presumed normal medical students of mean age 20 years have been examined. The results suggest that duplex scanning has the ability to grade less than 50% carotid disease into normal, 1-24% and 25-49% stenosis categories. The most sensitive indicator of early disease is obtained from the real-time B-scan. The waveform changes of the maximum frequency envelope were more sensitive than spectral broadening except where full spectral broadening was present. For confident assessment, the real-time B-scan and pulsed Doppler must always be used in conjunction.

Ultrasound in the diagnosis of the early liver abscess.

An analysis has been made of the ultrasound studies of 29 patients with proven liver abscesses. Ten of these were first seen in the early stages of abscess formation and a detailed study of the echo characteristics has been made. Helpful features have been shown to include a peripheral echo-free halo, distal acoustic enhancement and progressive change over a short time. These features are highly suggestive of an early abscess and, in our experience, this combination is not seen in other space-occupying lesions of the liver. We consider them to have considerable diagnostic value.

Case report: life-threatening hypercalcaemia secondary to pancreatic tumour secreting parathyroid hormone-related protein--successful control by hepatic arterial embolization.

Parathyroid hormone-related protein elaborated by pancreatic neuro-endocrine tumours can cause life-threatening hypercalcaemia. This is the first reported case where hypercalcaemia caused by such a tumour has been successfully controlled by hepatic arterial embolization.

Hepatic arterial embolisation in patients with metastatic carcinoid tumours.

Hepatic arterial embolisation was performed in six patients with malignant carcinoid tumours; five with the carcinoid syndrome and the other with intractable pain due to pleural and hepatic metastases. A total of 11 embolisations was performed, each time producing noticeable symptomatic relief, especially of facial flushing and diarrhoea. Apart from occasional episodes of the post-embolisation syndrome, no significant complications were experienced. Relief of symptoms lasted 2 months to 18 months in all patients with the carcinoid syndrome. Repeat embolisation was performed in three of the six patients. Three of the six patients have died at intervals ranging from 3 weeks to 20 months after the last embolisation. The cause of death was not related to embolisation. Hepatic embolisation is an effective, safe and repeatable method of palliating the symptoms of the carcinoid syndrome.

Transluminal dilatation in the management of mesenteric angina: a report of two cases.

Two patients with typical clinical and angiographic findings of mesenteric angina are reported. Both remain asymptomatic seven and 11 months respectively, after transluminal dilatation of superior mesenteric artery stenoses.

The effects of vitamin E-deficiency on serum prolactin and serum luteinising hormone levels in the pregnant rat.

No significant differences were observed between the serum prolactin or serum LH levels of vitamin E-deficient or vitamin E-replete rats during the first 12 days of gestation. It is suggested that pituitary dysfunction is not the cause of the characteristic foetal resorption observed in vitamin E-deficient rats.

Rebreathing techniques for pulmonary capillary blood flow and tissue volume.

The variability of three methods of calculating pulmonary capillary blood flow (Qc) and pulmonary tissue plus capillary blood volume (Vt) during rebreathing was assessed in normal humans by using as markers acetylene, ethyl iodide, and dimethyl ether. The methods of analysis were as follows. Method I, the timing of the disappearance curves of the soluble gases was corrected by assuming that the C18O-disappearance curve intercepted at unity at time O. Method II, it was assumed that the acetylene Qc calculated by method I was correct; ethyl iodide and dimethyl ether Vt were solved by an equation using the disappearance slopes of these gases and the acetylene Qc value, thereby avoiding dependence on extrapolated intercept values. Method III, Vt was calculated by solving for a unique value of Qc between pairs of disappearance slopes of acetylene and dimethyl ether, acetylene and ethyl iodide, and ethyl iodide and dimethyl ether. Among the three methods, method I gave the most reproducible values for Vt as determined with acetylene or dimethyl ether. Using method I, both acetylene and dimethyl ether were equally acceptable gases for measurement of Vt; acetylene was a better marker for Qc measurements.

Prospective randomized controlled trial of hepatic arterial embolization or infusion chemotherapy with 5-fluorouracil and degradable starch microspheres for colorectal liver metastases.

Survival benefit from hepatic artery embolization (HAE) or hepatic arterial infusion chemotherapy (HAI) in patients with unresectable colorectal liver metastases has not previously been assessed in a randomized controlled trial. Sixty-one patients were randomized, 20 to receive no treatment, 22 to receive HAE, and 19 to receive HAI with 5-fluorouracil and degradable starch microspheres. Both treatments were acceptable to the patients in terms of low treatment morbidity rate. Median survival from diagnosis of metastases was 9.6 months for controls, 8.7 months for the HAE group and 13.0 months in the HAI group. There was no apparent survival benefit for the HAE group. The increased survival in the HAI group was observed in all the subgroups analysed but failed to reach statistical significance. The greatest observed benefit was achieved in the subgroup with less than 50 per cent hepatic replacement with tumour at presentation (median survival from diagnosis 10.0 months for controls, 10.2 months for HAE and 23.6 months for HAI); 36 per cent of patients developed extrahepatic disease recurrence. No significant benefit has been shown from either HAE or HAI, but a more carefully selected group of patients with only low volume hepatic disease may benefit from HAI therapy.

Liver tumour blood flow and responses to arterial embolization measured by dynamic hepatic scintigraphy.

Liver and tumour blood flow has been studied in 30 patients with multiple liver metastases and in 14 patients with solitary liver tumours by means of dynamic hepatic scintigraphy. Observations were compared with those of a group of 33 control subjects. Haemodynamic changes were also measured in 10 patients who underwent hepatic arterial embolization (HAE). The mesenteric fraction (MF) to tumour regions in 32 subjects showed a wide range compared with control subjects. In 9 patients the MF to the tumour region was within the normal range suggesting that some tumours may possess a portal venous supply. The MF to the uninvolved liver regions was below the normal range in 25% of patients, indicating that HAE could be hazardous in this group. Following HAE the MF rose in all 4 tumour regions and fell in 4 non-embolized uninvolved liver regions. No increase in colloid clearance rate (k) was seen though a significant decrease occurred in 4 patients. These changes may well represent increased portal venous flow into tumours.

Duplex ultrasound assessment of femorodistal grafts: correlation with angiography.

Fifty-eight grafts have been assessed using duplex scanning and ankle brachial pressure indices. This assessment is compared with the findings by angiography. Eighteen grafts were occluded and 40 patent. Duplex scanning defined graft status with a greater accuracy than pressure indices. Pressure indices alone would not differentiate "satisfactory" grafts from those with localised, haemodynamically significant disease. Only 55% of those grafts with localised stenoses demonstrated a fall of greater than 0.2 in ankle brachial pressure index after exercise. When the information obtained using pressure indices and duplex scanning was combined non-invasive assessment had a sensitivity of 86% and specificity of 94% for detection of localised, haemodynamically significant disease in patent grafts. Haemodynamically significant disease, as defined by angiography, can be detected and localised with duplex scanning complementing the use of pressure indices in graft assessment.

Percutaneous transluminal dilatation of the renal artery: follow-up studies on renovascular hypertension.

Percutaneous transluminal dilatation of 80 renal artery stenoses was attempted in 68 patients. The procedure was technically successful in 58 (85%) patients. Fifty (86%) of the 58 patients were initially cured or improved. Life-table analysis of this group gives a cumulative success rate of 81% for a 3 year period. Hypertension recurred in only seven patients. There were no deaths related to the procedure, but four major complications occurred, including two secondary nephrectomies.