Waveform analysis for the detection of airways obstruction in man

The mathematical analysis of respiratory signals has been suggested as a safe noninvasive method for the diagnosis of airways obstruction in man. It involves (i) recording the respired air volume against time waveform for the deep and rapid breathing manoeuvre, (ii) digitising the analogue waveform and (iii) processing the data on a digital computer. The fast Fourier transform technique is used to process the data to yield the amplitude/power spectrum of the waveform. It is shown that, with the aid of the spectrum, it is possible to distinguish between the breathing waveform of a patient suffering from airways obstruction (AWO) and a normal subject (free from AWO). The paper presents results based on a study of the analysis of the respiratory volume signals of 85 subjects (both normals and patients) and suggests that this technique be used as a mass screening diagnostic test for AWO. The processing of the signals and subsequent diagnosis can be performed online with the aid of a microprocessor-based computer system.     

Influence of age on the immediate cardiovascular response to orthostatic manoeuvre

The dynamics of cardiovascular changes following standing up from the supine position were investigated in 41 healthy men aged 20–59 years, classified into three groups: (22–26 years, n = 14), (33–49 years, n = 13) and (51–59 years, n = 14). The protocols consisted of a sequence repeated twice lying down-standing up-lying down. The initial period supine was for 20 min and then the subjects remained in each position for 8 min. Stroke volume, cardiac output (CO), ejection time (ET), pre-ejection period and heart rate (HR) were continuously calculated using automated impedance cardiography and electrocardiography. Blood pressure was measured by the auscultation method. The patterns of HR and haemodynamic orthostatic response were shown to be highly reproducible. Most of the indices characterizing the amplitude and rate of cardiovascular changes following standing up showed a tendency towards attenuation with age. However, only the indices of HR, CO and ET responses correlated significantly with age. The strongest relationships with age were observed in the sudden increase in HR (n = – 0.61, P < 0.01), the transient increase in CO (r = – 0.45, P < 0.001), and the rapid decrease in ET (r = 0.42, P < 0.01) after standing up. A few indices of HR and haemodynamic response also showed weak correlations with the subjects' heights and body masses.     

A comparison of sleep nasendoscopy and the Muller manoeuvre

Knowledge of the level of pharyngeal obstruction during sleep is an important factor in deciding whether or not a patient suffering from obstructive sleep apnoea syndrome (OSAS) will benefit from uvulopalatopharyngoplasty. The Muller manoeuvre has been advocated as a method of obtaining this information. We compared the findings from the technique of sleep nasendoscopy, which actually allows visualization of the level of obstruction in the sleeping patient, with the results of the Muller manoeuvre performed in the same patients while awake. We found the Muller manoeuvre to be less accurate than previously believed.     

对演习人员心理状况调查分析

目的研究野外条件下实兵对抗演习中参演人员中各类参演人群的心理状况,以减少官兵因焦虑、抑郁等情绪在军事行动中引起的非战斗性减员。方法应用症状自评量表（SCL-90）对某兵站实兵对抗121名参演人员进行了焦虑、抑郁等情绪相关测试和分析。结果兵站人员的躯体化、抑郁及焦虑因子分值高于军人常模（P〈0.05）,非现役文职人员的症状总分高于兵站干部、士兵（均P〈0.05）,其中焦虑、恐怖及敌对3个因子分值高于干部、士兵（均P〈0.05）,士兵的各项得分与干部无明显差异（均P〉0.05）。结论对抗演习可使参演人员心理状况低下,心理问题的发生与环境的改变和人员身份类别有一定关系。     

Dramatic dilatation of the upper airway secondary to a Valsalva manoeuvre in a lateral cephalometric teleradiograph of a child

Radiographs are routinely used by orthodontists for the planning of treatment for their patients and they can, in some cases, play a decisive role in the early diagnosis of some unexpected medical or surgical disorders. This report presents the case of a substantial dilatation of the upper airway in a 10-year-old girl, which was attributed to a forced Valsalva manoeuvre. The diagnosis was confirmed upon repetition of the teleradiograph with the mouth open.     

The open lung concept: effects on right ventricular afterload after cardiac surgery

Background. The open lung concept (OLC) is a method of ventilationintended to maintain end-expiratory lung volume by increasedairway pressure. Since this could increase right ventricularafterload, we studied the effect of this method on right ventricularafterload in patients after cardiac surgery. Methods. We studied 24 stable patients after coronary arterysurgery and/or valve surgery with cardiopulmonary bypass. Patientswere randomly assigned to OLC or conventional mechanical ventilation(CMV). In the OLC group, recruitment manoeuvres were applieduntil was greater than 50 kPa (reflecting an open lung). This value was maintained by sufficient positiveairway pressure. In the CMV group, volume-controlled ventilationwas used with a PEEP of 5 cm H₂O. Cardiac index, right ventricularpreload, contractility and afterload were measured with a pulmonaryartery thermodilution catheter during the 3-h observation period.Blood gases were monitored continuously. Results. To achieve > 50 kPa, 5.3 (3) (mean, SD) recruitment attempts were performed with a peak pressureof 45.5 (2) cm H₂O. To keep the lung open, PEEP of 17.0 (3)cm H₂O was required. Compared with baseline, pulmonary vascularresistance and right ventricular ejection fraction did not changesignificantly during the observation period in either group. Conclusion. No evidence was found that ventilation accordingto the OLC affects right ventricular afterload.     

Evidence that imipramine-induced postural hypotension may be centrally mediated

The acute effects of imipramine upon cardiovascular reflexes have been studied in normal volunteers. Respiratory sinus arryhthmia, blood pressure and heart rate responses to standing, heart rate response to Valsalva's manoeuvre and the heart rate and blood pressure responses to isometric exercise were measured before and after 100 mg and 40 mg imipramine orally on separate occasions. Neither dose had an appreciable effect upon respiratory sinus arrhythmia (RSA), heart rate response to Valsalva or the responses to isometric exercise. Imipramine caused dose-related rises in resting heart rate and blood pressure. In view of the unchanged RSA these cannot be attributed to vagal blockade and may reflect peripheral noradrenaline reuptake inhibition. Imipramine profoundly altered the heart rate response to standing in a dose-related manner. This suggests an impairment of the orthostatic reflex. The presence of normal responses to the Valsalva manoeuvre and isometric exercise suggests that peripheral mechanisms were intact, and it is therefore likely that impairment of the orthostatic reflex is due to the effect of imipramine upon central monoaminergic neurones normally involved in this response.     

Anatomical justification of Belghiti's 'liver hanging manoeuvre' in right hepatectomy with anterior approach

Background: In cases of right hepatectomy for huge tumour encroaching onto the diaphragm, the ‘anterior approach’ is the most common surgical procedure undertaken. The ‘liver hanging manoeuvre’ has been described previously as an adjunct to this pro­cedure. It involves the dissection of a retrohepatic avascular plane anterior to the surface of the inferior vena cava. A tape is then passed through and the liver is resected under suspension. Methods: Cadaveric specimens were used to identify the structural relationship of the avascular plane and also to determine whether it is truly avascular. Results: Thirteen cases were analysed. The mean length of the avascular tunnel was 6.4 ± 1.0 cm. The median number of accessory hepatic veins within the tunnel was two (zero to three). At the caudal half of the tunnel, the median number of veins was two (zero to three). As for the cranial half of the tunnel, there were two cases with one vein in each. Conclusions: The key to the liver hanging manoeuvre is to develop the retrohepatic tunnel. However, our study showed that it is not absolutely avascular. During the blind dissection, there is a chance of damaging a retrohepatic vein. This may result in troublesome haemorrhage within the confines of the tunnel. Video‐assisted dissection of this region may help in visualisation, and hence control, in order to avoid bleeding.     

Multilobular Cavernous Malformation: Report of Two Cases

Summary The authors report two cases of cavernous malformation characterized by a multilobular appearance on magnetic resonance images. At surgery, the malformations consisted of several nests of angiomatous components that were separated by intervening brain tissue and connected with each other by tiny vessels. This basic configuration seems to explain the unexpected postoperative recurrence of cavernous malformations and/or rebleeding from the residual lesions.     

Topical application of decongestant in dysfunction of the Eustachian tube: a randomized,double-blind,placebo-controlled trial

Thirty-six patients, aged 12–75 years, with dry, central tympanic membrane perforations and a negative Valsalva manouevre and/or a negative aspiration/ deflation test, were included in a randomized, double-blind, placebo-controlled trial on the effect of a decongestant agent (xylometazoline chloride 0.1%) and placebo (saline 0.9%) applied directly to the pharyngeal opening of the Eustachian tube. Judged by the Valsalva manouevre, tubal patency was significantly improved after application of the active drug (P<0.003). In contrast, no effect was demonstrated by the aspiration test (P=0.80) or the deflation test (P=0.51). It is concluded that a topical decongestant improves Eustachian tube function but only at unphysiologically high pressures.