Simultaneous cerebral and spinal fluid pressure recordings

Summary Simultaneous intraventricular and intraspinal pressure recordings in erect patients with obstructive lesions of the CSF pathways reveal differences in pressure which are frequently transitory and produced by pulsation. In nonacute cases without papilloedema but with suspected hindbrain hernia delay in equalization after pressure pulses may be demonstrated, and after Valsalva's manoeuvre differences between the head and the spine may be generated transiently and be responsible for clinical symptomatology. The particular clinical features related to hindbrain hernia are syringomyelia, cough headache, cough syncope, and lower cranial nerve signs with oscillopsia and cerebellar ataxia. Correction of the pressure dissociation is often associated with marked clinical improvement. It is suggested that this form of testing may be of relevance as an indication for operation and also for monitoring the progress of post-operative patients.     

Cardiac Beat to Beat Variation: Age Related Changes in the Normal Population and Abnormalities in Diabetics*

Abstract: Determination of heart rate variation (RR interval variation) is a non-invasive technique which may be used for assessment of diabetic autonomic dysfunction. Interpretation has been complicated by age changes in the normal population and by uncertainty as to the optimum conditions for the performance of the test. This study was designed to establish a normal age-related range for RR interval variation performed under the simplest conditions (resting, seated) applicable to an outpatient diabetic clinic and to compare these measurements with augmented RR variation due to deep breathing (ARRIV) and with the Valsalva ratio (VR ).
Using an ECG recorder and a computer analysis program, resting RR interval variation (RRIV) was assessed in 100 non-diabetics (N) aged 12–80 years and 60 randomly selected diabetics (D) aged 14–74 years. RRIV, the standard deviation of RR intervals, declined progressively after age 40 in normal subjects. The diabetics had significantly (p < 0.001) reduced RRlV compared with normals; 65% having RRIV values more than 1 SD and 25% more than 2 SD below the age related mean for normals.
RRlV was compared with ARRIV in 54 subjects (N40, 014) and with VR in 84 subjects (N54, D27). There was a significant correlation of RRlV with both indices but RRlV resulted in greater discrimination between N and D than ARRIV or VR. There was no significant correlation between RRlV and duration of diabetes but mean RRlV was significantly reduced in diabetics with peripheral neuropathy compared to those without. In seven diabetics studied both before and after substantial improvement in metabolic control RRlV improved by a mean of 51% (p < 0.005).
Measurement of RRlV is a simple non-invasive technique for assessment of diabetic autonomic dysfunction. Interpretation, however, depends on knowledge of an age-related reference range.     

入肝血流阻断法肝切除术的围手术期护理

目的总结入肝血流阻断法肝切除术的围手术期护理经验。方法回顾性分析安徽医科大学第一附属医院肝胆外科47例成功实施入肝血流阻断法肝切除术患者临床护理资料。结果 47例患者均顺利完成手术,9例患者出现术后并发症,并发症发生率为19%（9/47）,经对症治疗后,所有患者均痊愈出院。结论入肝血流阻断法肝切除术手术疗效良好,术中出血少,术后并发症发生率低,是一种安全有效的肝脏疾病治疗方法,严谨细致的围手术期护理对手术的成功实施及术后患者的快速恢复起着至关重要的作用。     

Comparison between objective and subjective benign paroxysmal positional vertigo: clinical features and outcomes

Conclusions: Objective benign paroxysmal positional vertigo (O-BPPV) and subjective BPPV (S-BPPV) have similar demographic and clinical features. Canalith repositioning manoeuvres (CRMs) can be an effective treatment for patients with S-BPPV, and a diagnosis of positional nystagmus is not essential for considering CRMs. This study supports the use of CRMs as the primary treatment for S-BPPV.

Objective: To examine differences in demographic and clinical features, as well as treatment outcomes, between O-BPPV and S-BPPV.

Methods: The medical records of 134 patients with BPPV were reviewed for demographic characteristics, past medical history, associated symptoms, response to CRMs, interval between symptom onset and the first medical visit, and recurrence rate. The O-BPPV group (n?=?101) comprised patients who experienced vertigo and accompanying autonomic symptoms, and showed typical nystagmus. The S-BPPV group (n?=?33) comprised patients who, when subjected to a provoking manoeuvre, showed all of the classic BPPV symptoms but did not show nystagmus. All patients had at least 3 years of follow-up.

Results: The demographics (age and sex ratio), past medical history, and associated symptoms were not significantly different between the two groups. Posterior semi-circular canal BPPV appeared more than twice as often as horizontal semi-circular canal BPPV in patients with S-BPPV. However, both canals were affected to a similar proportion in patients with O-BPPV, and the difference was marginally significant (p?=?0.073). Overall improvement was better in O-BPPV than in S-BPPV; however, there was no significant difference. The total numbers of manoeuvres for recovery and the interval between symptom onset and the first medical visit also did not show any significant inter-group differences. During a 3-year follow-up, the recurrence rate was 13.8% for O-BPPV and 21.2% for S-BPPV.     

The influence of operator and wheelchair factors on wheelchair propulsion effort

Abstract

Purpose: The goal of this study was to evaluate the relative influence of operator and wheelchair factors on propulsion effort during over-ground wheelchair manoeuvres.

Method: This observational study included 23 full-time manual wheelchair users and 13 able-bodied subjects. The operator factors included shoulder position, aerobic capacity and propulsion strength. The wheelchair factors included system mass, weight distribution, and frictional loss in straight and turning trajectories. The performance of over-ground manoeuvres was defined as the propulsion effort measured by VO₂ as operators propelled along a modified figure-8 course on tile and carpet surfaces.

Results: According to our regression model, shoulder position was the only significant contributor within operator factors, whereas weight distribution was the only significant contributor within wheelchair factors in influencing propulsion efforts. When combining operator and mechanical factors in the regression model, weight distribution became the only significant contributor to influence propulsion effort.

Conclusion: Weight distribution and shoulder position had a significant influence on propulsion effort. These variables are related to the operator’s relationship to the drive wheels. However, system mass and muscle strength had the least influence on wheelchair manoeuvres. Our finding can help clinicians to improve wheelchair configurations and manufacturers to improve wheelchair design by understanding the importance of shoulder position and weight distribution.

• Implication for rehabilitation

• Studying wheelchair manoeuvers by considering both wheelchair and operator factors might provide a unique insight to address the complex interactions among wheelchair designs and users.

• Propulsion effort decreases as percentage weight is increased on the drive wheels and the shoulder becomes more aligned with the axle position, which highlights the need to optimize wheelchair axle position.

• Wheelchair configuration, as represented by weight distribution, had a more significant influence on everyday manoeuvre than wheelchair mass does.

• It is essential for wheelchair users to choose a wheelchair that can match their daily needs and anthropometric measurements for saving propulsion efforts.

     

Comparison of the influence of aerobic and resistance exercise of the upper and lower limb on intraocular pressure

Purpose: To compare the influence of aerobic and resistance exercise on intraocular pressure (IOP). Methods: Twenty‐one healthy subjects participated. Aerobic exercise was performed using a cycle ergometer, and resistance exercise was performed with a leg curl and a butterfly machine. Intraocular pressure was measured at baseline, during exercise and 10 min after. During resistance exercise, a Valsalva manoeuvre was prevented. Results: Before aerobic exercise, the mean IOP was 18.8 ± 2.7 mmHg. It was 16.5 ± 2.8 after 10, 17.1 ± 2.6 after 20 and 16.7 ± 3.3 mmHg after 30 min of exercise. After 10 min, the IOP returned to baseline (18.8 ± 2.7 mmHg). The mean IOP before resistance exercise with the leg curl machine was 17.0 (15.6–18.4; 65%W_max) and 16.8 (15.3–18.3) mmHg; 75%W_max) and did not change significantly during the experiment. The mean IOP before resistance exercise with the butterfly machine (65%W_max) was 16.4 (15.2–17.6) and increased to 17.2 (16.0–18.4) mmHg (p < 0.05). After 10 min of recreation, it recovered to 16.3 (15.0–17.5) mmHg. At 75%W_max, the mean baseline IOP was 16.3 (15.2–17.4) mmHg, and there were no significant changes. Conclusions: Aerobic exercise leads to a significant decrease of IOP. There was no influence of resistance exercise on IOP as long as a Valsalva manoeuvre was prevented.     

Inherited Sensorineural Low-Frequency Hearing Impairment: Some Aspects of Phenotype and Epidemiology

This study retrospectively analysed how 20 patients with posterior canal benign paroxysmal positional vertigo (BPPV) were managed from primary care, to treatment in tertiary care. The average time from first referral to treatment was 93 weeks, with an average of 58 weeks within primary care and 40 weeks within hospital care. At least 85% of cases had classical symptoms of BPPV and could have been easily identified by Primary Care Physicians at first referral, had they been trained to recognise and diagnose the condition. It was concluded that patients could be treated more efficiently and at less cost if the condition was identified at first referral in primary care, and treated in either primary care or dedicated BPPV clinics receiving referrals from primary care. A dedicated clinic for BPPV is recommended, which will substantially reduce waiting time for treatment and save primary care and hospitals time and money by avoiding unnecessary appointments and medication.     

Response patterns of arterial pressure and heart period to Mueller manoeuvre and their comparison to those of Valsalva manoeuvre

Objective: It has not been established if the Mueller manoeuvre (MM) induces characteristic arterial pressure (AP) and heart rate changes analogous to those observed during its respiratory strain opposite, the Valsalva manoeuvre (VM). Our aims were to explore, on a beat‐by‐beat basis, if MM evokes well‐defined changes in AP and heart period (HP), and to compare these responses with those of VM. Methods: From the ECG and AP records of 24 healthy subjects who performed VM and MM in sitting position, RR intervals and AP series were computed. The series were ensemble‐averaged, and the characteristic points that limit the phases were semi‐automatically detected from each record. Results: Our main findings were: (i) MM provoked consistent patterned responses in both AP and HP in the same four phases of VM; (ii) the AP and HP changes of MM were parallel to those of VM in phases II and IV, and opposite in direction in phases I and III; (iii) pooled data during the strain and poststrain and the mean characteristic points of AP and HP were smaller in MM than in VM (P<0·001); (iv) MM presented two changes absent in VM, AP and HP rise immediately after phase I and hypotension in late phase IV; (v) systolic pressure and HP presented a strong positive correlation (r = 0·87 ± 0·02) in late phase II of MM. Conclusion: Our study characterizes on a phase‐by‐phase basis the AP and RR interval responses to MM, documents their great similarity to those corresponding to VM and establishes that MM exerts a 50% smaller impact on the cardiovascular autonomic function than VM.     

Solving mixed‐integer optimal control problems by branch&bound: a case study from automobile test‐driving with gear shift

The article discusses the application of the branch&bound method to a mixed integer non‐linear optimization problem (MINLP) arising from a discretization of an optimal control problem with partly discrete control set. The optimal control problem has its origin in automobile test‐driving, where the car model involves a discrete‐valued control function for the gear shift. Since the number of variables in (MINLP) grows with the number of grid points used for discretization of the optimal control problem, the example from automobile test‐driving may serve as a benchmark problem of scalable complexity. Reference solutions are computed numerically for two different problem sizes. A simple heuristic approach suitable for optimal control problems is suggested that reduces the computational amount considerably, though it cannot guarantee optimality anymore. Copyright © 2005 John Wiley & Sons, Ltd.