Optimum Position for an Antisiphon Device in a Cerebrospinal Fluid Shunt System

Neurosurgery ◽  
1991 ◽  
Vol 29 (4) ◽  
pp. 519-525 ◽  
Author(s):  
Kazuhiko Tokoro ◽  
Yasuhiro Chiba
Keyword(s):  
Supine Position ◽  
Normal Pressure ◽  
Low Pressure ◽  
Sitting Position ◽  
Foramen Of Monro ◽  
Shunt System ◽  
Shunt Valve ◽  
Shunt Flow ◽  
Optimum Position ◽  
Antisiphon Device

Abstract The effects on shunt flow from the position of an antisiphon device (ASD) and from changes in posture in hydrocephalic patients were examined. Fifty patients with hydrocephalus (including 36 with normal pressure hydrocephalus) were investigated, using quantitative radionuclide shuntography (99mtechnetium-pertcchnetate) in the supine, sitting, and standing positions. The types of shunt valve used were as follows: Mishler dual chamber low pressure without ASD (16 cases), with ASD 40 cm below the level of the foramen of Monro (three cases), and with ASD 10 cm below the level of the foramen of Monro (12 cases); low pressure with integral ASD (14 cases); and medium pressure with integral ASD (five cases). In patients with a low pressure valve without ASD, shunt flow was least in the supine position (0.0011 ml/min) but increased significantly in the sitting position (0.4381 ml/min, P < 0.001) because of the siphon effect. Conversely, in patients with a low pressure valve with integral ASD, shunt flow was maximal in the supine position (0.1056 ml/min) and decreased significantly in the sitting position (0.0017 ml/min, P < 0.001), indicating overfunction of the ASD. Intracranial pressure (ICP) in the supine position increased significantly compared with patients with a low pressure valve without ASD (93.6 and 20.7 mm H2O. respectively, P < 0.01). Intermediate values for shunt flow in the supine and sitting positions (0.0279 and 0.0896 ml/min, respectively) and for ICP (55.8 mm H2O) were obtained with patients with a low pressure valve with the ASD 10 cm below the level of the foramen of Monro P < 0.05). Shunt flow in the supine position correlated negatively with the log of the shunt flow in the sitting position (P < 0.025). Shunt flow in the sitting position correlated positively with the distance between the ASD and the level of the foramen of Monro (P < 0.01). ICP in the supine position correlated negatively with the distance between the ASD and the level of the foramen of Monro (P < 0.025). Shunt flow and ICP are significantly affected by the position of the ASD and the patient's posture. The optimum position for the ASD appears to be 10 cm downstream; the resulting hydrostatic column helps initiate flow when the patient assumes the sitting and standing positions.

New concept for the pressure setting of a programmable pressure valve and measurement of in vivo shunt flow performed using microflow meter

2000 ◽  
Vol 92 (1) ◽  
pp. 181-187 ◽  
Author(s):  
Hiroji Miyake ◽  
Tomio Ohta ◽  
Yoshinaga Kajimoto ◽  
Kohji Nagao
Keyword(s):  
Normal Pressure ◽  
Intraabdominal Pressure ◽  
Sitting Position ◽  
Content Type ◽  
Shunt Flow ◽  
Pressure Setting ◽  
Programmable Pressure Valve ◽  
Fine Print ◽  
The Ideal

✓ The aim of this study was to establish a standard method for determining the pressure setting of the Codman Hakim valve (CHV) in patients with hydrocephalus.The authors' investigation was twofold. It focused on: 1) the relationships among CHV setting, intracranial pressure (ICP), intraabdominal pressure (IAP), hydrostatic pressure (HP), and perfusion pressure (PP); and 2) the shunt flow in 18 patients with normal-pressure hydrocephalus.With the patient in a sitting position, the pressure environment around the ventriculoperitoneal shunt stabilized when PP became equal to the CHV setting. The lower the CHV setting, the lower the ICP obtained in patients in a sitting position (ICPsit) settled. This indicated the possibility of calculating the CHV setting by the equation CHV setting = HP + ideal ICPsit − IAP, where the ideal ICPsit was estimated to be between −70 and −140 mm H2O. The CHV setting was individually determined for 18 patients by using this method. The ICPsit was controlled at a level equal to the estimated ICPsit in most cases, which supported the rationality of our concept. Shunt flow was intermittent or very low when the patient assumed a supine position and between 200 and 600 µl/minute when the patient was seated.Determining the CHV setting by using the equation CHV setting = HP + ideal ICPsit − IAP was found to be useful when directly measuring HP and IAP in patients and estimating the ideal ICPsit to be between −70 and −140 mm H2O. Postoperative shunt control performed using this method was satisfactory, and shunt complications and the number of CHV resettings were lower than in those published in previous reports.Shunt-flow measurement performed in vivo and in real time by using a microflowmeter should be useful not only in testing the functioning of shunt systems, but also in clarifying the pathophysiology of hydrocephalus.

scholarly journals P248 Changes of atrial septum defect caused by posture during three-dimensional transesophageal echocardiography ( a case of Platypnea-orthodeoxia syndrome)

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
Y Takeuchi ◽  
S Suzuki ◽  
H Tsuneyoshi ◽  
H Sakamoto ◽  
T Shimada
Keyword(s):  
Blood Flow ◽  
Transesophageal Echocardiography ◽  
Supine Position ◽  
Three Dimensional ◽  
Atrial Septum ◽  
Arterial Oxygen ◽  
Sitting Position ◽  
Postural Change ◽  
Right Heart ◽  
Shunt Flow

Abstract Background Platypnea-Orthodeoxia syndrome (POS) is a rare phenomenon which is characterized postural hypoxia due to the intracardiac shunt from right to left through a patent foramen ovale, an atrial septal defect or a pulmonary arteriovenous malformation. POS is often underestimated because the hypoxia by postural change is difficult to be detected. We evaluated three-dimensional transesophageal echocardiography (TEE) to diagnose POS in an elderly patient. Case report A 84-year-old woman suffered from repetitive syncope for several years. She undertook twelve leads electrocardiogram (ECG), screening transthoracic echocardiography (TTE), twenty-four hours ECG and treadmill stress ECG, however, the cause of syncope was not identified. After another syncope event happened, she was transferred to the emergency room. Then, the hypoxia caused by sitting position was pointed out for the first time. Her hypoxia was improved by supine position and oxygen administration. TTE demonstrated no right heart enlargement. Shunt flow was suspected on her atrial septum; however, it was difficult to reveal it by TTE because of her obesity. Therefore, she underwent intravenous saline injection test. In the decubitus position, an intravenous injection of saline under Valsalva maneuver revealed the shunt flow from the right atrium to the left atrium. Her arterial oxygen saturation (SpO2) was 95%. In the sitting position, a visible shunt flow was observed, then her SpO2 dropped to 85%. By TEE, the shunt hole was found in the oval fossa of the atrial septum. TEE was evaluated by different positions. The atrial defect hole became larger in the sitting position (area 1.05cm2) than in the supine position (area 0.43cm2). As a result, the postural change to sitting revealed Platypnea-Orthodeoxia syndrome associated with ASD. The pulmonary blood flow/systemic blood flow ratio (Qp/Qs) was estimated at 1.6. After surgical ASD closure, she was discharged without any symptoms. Conclusion Unclearness of TTE and the absence of a right heart overload may lead to misdiagnosis of POS. If a syncope patient caused hypoxia in the only sitting position, detailed echocardiography should be needed to rule out a diagnosis of POS. This is considerably valuable case of three-dimensional TEE confirmed the changes of ASD size by postural change. Abstract P248 Figure.

Malfunction of V-P Shunt System Equipped with Antisiphon Device in Normal-pressure Hydrocephalus

1990 ◽  
pp. 80-81
Author(s):  
Mitsuru Seida ◽  
Umeo Ito ◽  
Shuichi Tomida ◽  
Shingo Yamazaki ◽  
Yutaka Inaba
Keyword(s):  
Normal Pressure Hydrocephalus ◽  
Normal Pressure ◽  
Shunt System ◽  
Antisiphon Device

Surgical Management of Idiopathic Normal-pressure Hydrocephalus

Neurosurgery ◽  
2005 ◽  
Vol 57 (suppl_3) ◽  
pp. S2-29-S2-39 ◽  
Author(s):  
Marvin Bergsneider ◽  
Peter McL. Black ◽  
Petra Klinge ◽  
Anthony Marmarou ◽  
Norman Relkin
Keyword(s):  
Surgical Management ◽  
Normal Pressure Hydrocephalus ◽  
English Language ◽  
Normal Pressure ◽  
Idiopathic Normal Pressure Hydrocephalus ◽  
Practical Reasons ◽  
Shunt System ◽  
Adjustable Valve ◽  
Pubmed Search ◽  
Antisiphon Device

Abstract OBJECTIVE: To develop evidence-based guidelines for surgical management of idiopathic normal-pressure hydrocephalus (INPH). Compared with the diagnostic phase, the surgical management of INPH has received less scientific attention. The quality of much of the literature concerning the surgical management has been limited by many factors. These include retrospective analysis, small patient numbers, analysis of a mixed NPH population, and sometimes a lack of detail as to what type of shunt system was used. Many earlier studies predated our current understanding of the hydrodynamics of cerebrospinal fluid shunts, and therefore, the conclusions drawn may no longer be valid. METHODS: A MEDLINE and PubMed search from 1966 to the present was conducted using the following key terms: normal-pressure hydrocephalus and idiopathic adult-onset hydrocephalus. Only English-language literature in peer-reviewed journals was reviewed. The search was further limited to articles that described the method of treatment and outcome selectively for INPH patients. Finally, only studies that included 20 or more INPH patients were considered with respect to formulating the recommendations in these Guidelines (27 articles). RESULTS: For practical reasons, it is important to identify probable shunt responders diagnosed with INPH. If the patient is an acceptable candidate for anesthesia, then an INPH-specific risk-benefit analysis should be determined. In general, patients exhibiting negligible symptoms may not be suitable candidates for surgical management, given the known risks and complications associated with shunting INPH. The choice of valve type and setting should be based on empirical reasoning and a basic understanding of shunt hydrodynamics. The most conservative choice is a valve incorporating an antisiphon device, with the understanding that underdrainage (despite a low opening pressure) may occur in a small percentage of patients because of the antisiphon device. On the basis of retrospective studies, the use of an adjustable valve seems to be beneficial in the management of INPH. CONCLUSION: The treatment of INPH should not be considered lightly, given the seriousness of the potential complications. Within these limitations and the available evidence, guidelines for surgical management were developed.

scholarly journals Reproducibility and agreement between three positions for handgrip assessment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Olga-Cecilia Vargas-Pinilla ◽  
Eliana-Isabel Rodríguez-Grande
Keyword(s):  
Supine Position ◽  
Cross Sectional Study ◽  
Sitting Position ◽  
Average Difference ◽  
Cross Sectional ◽  
Hand Grip ◽  
Standardization Process ◽  
The One ◽  
Level Of Agreement ◽  
Apparently Healthy

AbstractThe protocol established for taking hand grip dynamometry measurements determines that the patient must be in a sitting position. This protocol cannot be applied due to the patient’s conditions in some cases, such as abdominal surgery, musculoskeletal spine or hip injuries. The purpose was to determine the reproducibility and level of agreement between the Handgrip dynamometry in supine position with the elbow flexed or extended, and the one measured in the sitting position, the design was a descriptive cross-sectional study. The population were young apparently healthy between 18 and 30 years of age (N = 201). Handgrip measurement was performed on both upper limbs in a sitting position with a flexed elbow, a supine position with a flexed elbow, and supine position with the elbow extended. Reproducibility was nearly perfect in all positions (ICC 0.95–0.97). Regarding the level of agreement for the comparison between sitting and supine positions with a flexed elbow, an average difference of − 0.406. For supine position with an extended elbow and supine position with a flexed elbow, the average difference was − 1.479. Considering the results, clinicians or researchers can choose any of the positions evaluated herein and obtain reliable results as long as the standardization process is followed.

scholarly journals Experimental study on the effect of spray cone angle on the characteristics of horizontal jet spray flame under sub-atmospheric pressure

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2941-2952 ◽  
Author(s):  
Kai Xie ◽  
Xingqi Qiu ◽  
Yunjing Cui ◽  
Jianxin Wang
Keyword(s):  
Atmospheric Pressure ◽  
Cone Angle ◽  
Flame Temperature ◽  
Normal Pressure ◽  
Low Pressure ◽  
Dimensionless Temperature ◽  
Thermal Imager ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Matlab Programming

The burning state of a plateau environment is attracting more and more attention. In this paper, in order to have a deeper scientific understanding of diesel spray combustion and the characteristics of a flame under different spray cone angles in a plateau environment, experiments were carried out in a low pressure chamber. The flame morphology was recorded by a high speed video instrument, and the temperature change was recorded by a thermal imager and thermocouples. The MATLAB programming was used to process the video image of the flame, and the probability of its binarization was calculated. The results indicate that the flame becomes longer and wider under different pressures with the same spray angle. The variation is more pronounced at a smaller spray taper angle. The flame uplifted height characteristic is mainly negatively related to the atmospheric pressure. According to the normalized flame temperature and the dimensionless horizontal projection, the length can be divided into three regions. In the region of buoyancy flame, the dimensionless temperature varies with sub-atmospheric pressure more than with normal pressure. In addition, under different spray cone angle conditions, the law of variation in the normalized flame temperature under sub-atmospheric pressure is exactly opposite to that under normal pressure. This study is of great significance to the scientific research on flames in a low pressure environment, and the design of different fuel nozzles for application in a plateau environment.

scholarly journals Postural Changes in Measures of Arterial Stiffness in Hypertensive Subjects on Antihypertensive Drug Therapy: A Prospective, Pilot Study

2016 ◽  
Vol 26 (02) ◽  
pp. 078-082
Author(s):  
Du Jun ◽  
Chin Cheong ◽  
Ashish Sule
Keyword(s):  
Arterial Stiffness ◽  
Supine Position ◽  
Enzyme Inhibitor ◽  
Antihypertensive Drug Therapy ◽  
Rank Test ◽  
P Value ◽  
Sitting Position ◽  
Antihypertensive Medications ◽  
Postural Changes ◽  
Significant Difference

AbstractProspective study with a controlled arm to know if there are variations of measures of arterial stiffness with posture in subjects with hypertension on antihypertensive medications.We studied postural variations of measures of arterial stiffness in 21 subjects with diagnosed hypertension on antihypertensive medications and compared them with 21 normotensive subjects. All subjects underwent pulse-wave analysis on SphygmoCor in the morning between 8 am to 10 am initially in supine and then in sitting position after 3 minutes. Summary measures on demographics, and blood pressure characteristics at sitting and supine positions are obtained. Differences between characteristics at supine and sitting position are compared using nonparametric paired test of Wilcoxon signed-rank test. A value of p < 0.05 was accepted as statistically significant.Antihypertensive medications decreased the supine aortic augmentation pressure (AAP) and augmentation index (AI) but not significantly. When subgroups of patients with antihypertensive treatment were analyzed, it was noted that angiotensin-converting enzyme inhibitor and angiotensin receptor blocker group (12) decreased AAP and AI significantly in supine position compared with patients on other antihypertensive medications (9) (p-value 0.034 and 0.038, respectively). There was no significant difference in other groups of calcium channel blockers, β-blockers, or diuretics. However, in normotensive control arm, there was an increase in AAP and AI in the supine position.In hypertensive subjects, on antihypertensive, there was reduction in AAP and AI in supine position compared with those of normotensives. The significance of the decrease in AAP and AI in supine position on antihypertensive needs to be studied further.

scholarly journals Occurrence and management of postoperative pneumocephalus using the semi-sitting position in vestibular schwannoma surgery

2020 ◽  
Vol 162 (11) ◽  
pp. 2629-2636
Author(s):  
Kathrin Machetanz ◽  
Felix Leuze ◽  
Kristin Mounts ◽  
Leonidas Trakolis ◽  
Isabel Gugel ◽  
...  
Keyword(s):  
Posterior Fossa ◽  
Supine Position ◽  
Tumor Size ◽  
Clinical Symptoms ◽  
Neurosurgical Procedures ◽  
Posterior Fossa Surgery ◽  
Sitting Position ◽  
Tension Pneumocephalus ◽  
Replacement Procedure ◽  
Duration Of Surgery

Abstract Background The semi-sitting position in neurosurgical procedures is still under debate due to possible complications such as venous air embolism (VAE) or postoperative pneumocephalus (PP). Studies reporting a high frequency of the latter raise the question about the clinical relevance (i.e., the incidence of tension pneumocephalus) and the efficacy of a treatment by an air replacement procedure. Methods This retrospective study enrolled 540 patients harboring vestibular schwannomas who underwent posterior fossa surgery in a supine (n = 111) or semi-sitting (n = 429) position. The extent of the PP was evaluated by voxel-based volumetry (VBV) and related to clinical predictive factors (i.e., age, gender, position, duration of surgery, and tumor size). Results PP with a mean volume of 32 ± 33 ml (range: 0–179.1 ml) was detected in 517/540 (96%) patients. The semi-sitting position was associated with a significantly higher PP volume than the supine position (40.3 ± 33.0 ml [0–179.1] and 0.8 ± 1.4 [0–10.2], p < 0.001). Tension pneumocephalus was observed in only 14/429 (3.3%) of the semi-sitting cases, while no tension pneumocephalus occurred in the supine position. Positive predictors for PP were higher age, male gender, and longer surgery duration, while large (T4) tumor size was established as a negative predictor. Air exchange via a twist-drill was only necessary in 14 cases with an intracranial air volume > 60 ml. Air replacement procedures did not add any complications or prolong the ICU stay. Conclusion Although pneumocephalus is frequently observed following posterior fossa surgery in semi-sitting position, relevant clinical symptoms (i.e., a tension pneumocephalus) occur in only very few cases. These cases are well-treated by an air evacuation procedure. This study indicates that the risk of postoperative pneumocephalus is not a contraindication for semi-sitting positioning.

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