Non-shunted Group Research Articles

Short-term outcomes after selective shunt during carotid endarterectomy: A propensity score matching analysis

Introduction and objectivesCarotid cross-clamping during carotid endarterectomy might lead to intraoperative neurologic deficits, increasing stroke/death risk. If deficits are detected, carotid shunting has been recommended to reduce the risk of stroke. However, shunting may sustain a specific chance of embolic events and subsequently incurring harm. Current evidence is still questionable regarding its clear benefit. The aim is to determine whether a policy of selective shunt impacts the complication rate following an endarterectomy. Material and methodsFrom January 2013 to May 2021, all patients undergoing carotid endarterectomy under regional anesthesia with intraoperative neurologic alteration were retrieved. Patients submitted to selective shunt were compared to a non-shunt group. A 1:1 propensity score matching (PSM) was performed. Differences between the groups and clinical outcomes were calculated, resorting to univariate analysis. ResultsNinety-eight patients were selected, from which 23 were operated on using a shunt. After PSM, 22 non-shunt patients were compared to 22 matched shunted patients. Concerning demographics and comorbidities, both groups were comparable to pre and post-PSM, except for chronic heart failure, which was more prevalent in shunted patients (26.1%, P=0.036) in pre-PSM analysis. Regarding 30-day stroke and score Clavien–Dindo≥2, no significant association was found (P=0.730, P=0.635 and P=0.942, P=0.472, correspondingly, for pre and post-PSM). ConclusionsIn this cohort, resorting to shunting did not demonstrate an advantage regarding 30-day stroke or a Clavien–Dindo≥2 rates. Nevertheless, additional more extensive studies are mandatory to achieve precise results concerning the accurate utility of carotid shunting in this subset of patients under regional anesthesia.

Transcallosal approach and post-operative subdural collections: 12-year paediatric neurosurgery tertiary centre experience.

Following transcallosal surgery for tumour resection, the formation of convexity or interhemispheric subdural cerebrospinal fluid collections may lead to clinical deterioration and may influence decision-making with regards to additional interventions. The aim of this study was to determine the incidence, risk factors, and management of subdural collections following the transcallosal approach in a paediatric cohort. A retrospective case note and radiological review of all children who underwent transcallosal surgery for intraventricular and thalamic tumours was carried out covering a 12-year period (2012-2023) in a single-centre tertiary paediatric neurosurgery unit. Parameters including demographics and clinical information including lesion location, pathology, extent of resection, need for and type of shunt required, as well as depth, laterality, and location of the collection were analysed prior to shunting, and at approximately 3 weeks, 3 months, and latest follow-up available post-operatively in order to further elucidate the natural history of these subdural collections and their clinical significance. Sixty-four cases satisfied the inclusion criteria of transcallosal surgery for tumour resection; 13 did not have adequate post-operative imaging and were excluded. Of the remaining 51 cases, there were 32 children (63%) with post-operative CSF subdural collections, of which 59% were ipsilateral, with the remainder showing bilateral distribution. The overall shunt insertion rate was 25.5% (12 ventriculoperitoneal and 1 subdural-peritoneal shunt) at 3 months, with a mean time to shunting of 19 days post-operatively. Children who developed post-operative subdural collections had a higher rate of shunting, at 37.5%, compared to 5.2% in those who did not. Pre- and post-operative hydrocephalus and subtotal resection were identified as risk factors for development of subdural collections post-operatively. Subdural collections showed a natural course of reduction and regression over follow-up, with the exception of 3 children where they persisted or increased over time; although none of these required shunting. Those children who underwent shunt insertion showed greater regression in the size of the subdural collection over time compared to the non-shunted group. In this paediatric cohort, 25.5 % of children required insertion of a shunt by 3 months following transcallosal surgery. Pre- and post-operative hydrocephalus and subtotal tumour resection were risk factors for development of subdural collections post-operatively.

Short-term outcomes after selective shunt during carotid endarterectomy: a propensity score matching analysis

Introduction and objectivesCarotid cross-clamping during carotid endarterectomy might lead to intraoperative neurologic deficits, increasing stroke/death risk. If deficits are detected, carotid shunting has been recommended to reduce the risk of stroke. However, shunting may sustain a specific chance of embolic events and subsequently incurring harm. Current evidence is still questionable regarding its clear benefit. The aim is to determine whether a policy of selective shunt impacts the complication rate following an endarterectomy. Material and methodsFrom January 2013 to May 2021, all patients undergoing carotid endarterectomy under regional anesthesia with intraoperative neurologic alteration were retrieved. Patients submitted to selective shunt were compared to a non-shunt group. A 1:1 propensity score matching (PSM) was performed. Differences between the groups and clinical outcomes were calculated, resorting to univariate analysis. ResultsNinety-eight patients were selected, from which 23 were operated on using a shunt. After PSM, 22 non-shunt patients were compared to 22 matched shunted patients. Concerning demographics and comorbidities, both groups were comparable to pre and post-PSM, except for chronic heart failure, which was more prevalent in shunted patients (26.1%, P=0.036) in pre-PSM analysis. Regarding 30-day stroke and score Clavien–Dindo ≥2, no significant association was found (P=0.730, P=0.635 and P=0.942, P=0.472, correspondingly, for pre and post-PSM). ConclusionsIn this cohort, resorting to shunting did not demonstrate an advantage regarding 30-day stroke or a Clavien–Dindo ≥ 2 rates. Nevertheless, additional more extensive studies are mandatory to achieve precise results concerning the accurate utility of carotid shunting in this subset of patients under regional anesthesia.

Detection of right-to-left shunt with transthoracic contrast echocardiography in patients with pulmonary hypertension

Objective: To explore the value of right heart contrast echocardiography in etiological diagnosis and severity assessment of pulmonary hypertension (PH). Methods: A retrospective analysis was conducted on 74 patients who underwent transthoracic contrast echocardiography in China-Japan Friendship Hospital from May 2015 to July 2018, all of whom were diagnosed as PH by right heart catheterization. Patients were divided into three groups according to contrast echocardiography: the intra-cardiac shunt group (<4 cardiac cycles with microbubbles in the left heart); Intrapulmonary shunt group (>4 cardiac cycles with microbubbles in the left heart); non-shunt group. The etiology, partial arterial oxygen pressure (PO(2)), N-terminal pro-brain natriuretic peptide (NT-proBNP), mean pulmonary artery pressure (mPAP), right atrial pressure (RAP), pulmonary vascular resistance (PVR) and cardiac output (CO) were analyzed. Central nervous system complications were also compared among the three groups. Results: Among the 74 patients, right-to-left shunt was found in 28 cases (37.8%) by contrast echocardiography, including 11 cases (14.9%) of intra-cardiac shunt and 17 cases (23.0%) of intrapulmonary shunt. In the 11 cases of intra-cardiac shunt, 7 were diagnosed with congenital heart disease and 4 were patent foramen. Two with hereditary hemorrhagic telangiectasia (HHT) and 1 with pulmonary arteriovenous malformation (PAVM) were included in the 16 cases of intrapulmonary shunt. There was no statistical difference in PO(2), mPAP, PVR, NT-proBNP, RAP, CO and functional class among the three groups (all P>0.05). A total of 5 cases (6.8%) were found with nervous system comorbidities, 4 cases (5.4%) with cerebral infarction and 1 cases epilepsy, and 2 cases of cerebral infarction were diagnosed as paradoxical embolism. Nervous system complications were more common in patients with intra-cardiac shunt than in other groups. Conclusion: While right-to-left shunt detected by contrast echocardiography has no relationship with disease severity, it has complementary value in the etiological diagnosis of PH, and intra-cardiac shunt may increase the risk of nervous system complications.

Detection of atrial shunt lesions with asingle echocardiographic parameter.

SummaryBackgroundUnrepaired left to right atrial shunt lesions can cause significant right ventricular (RV) volume overload. The parameter pulmonary to systemic shunt volume ratio (Qp:Qs) has been shown to detect even small differences between left and right ventricular stroke volume; however, four parameters are needed for its calculation. This study was carried out to evaluate the accuracy of the single parameter right ventricular outflow tract (RVOT) velocity time integral (VTI) to identify atrial shunt lesions.MethodsAll patients who underwent transesophageal echocardiography (TEE) examination at this institution between 1 January 2013 and 1 January 2018 were retrospectively analyzed. The RVOT-VTI was measured in the transthoracic echocardiography performed immediately before each TEE. The diagnostic accuracy for detection of atrial shunt lesions was tested.ResultsA total of 2797 patients with a median age of 67 years (interquartile range, IQR 54–77 years) were included in the final analysis. A total of 113 (4%) patients had a relevant atrial shunt lesion. The mean RVOT-VTI of the shunt group was 25 cm (SD ± 8.1 cm) and was significantly higher than that of the non-shunt group with 17 cm (SD ± 4.8 cm) (p < 0.001). The area under the curve (AUC) was 0.81. A total of 106 patients (93.8%) of the shunt group had a VTI of ≥16 cm. If the RVOT-VTI was <16 cm, the negative predictive value was 99.3%. If the RVOT-VTI was ≥25 cm, 22% of patients proved to have a significant shunt lesion.ConclusionIn this large retrospective analysis it could be shown that a low RVOT-VTI predicted the absence of significant atrial shunt lesions, while a high RVOT-VTI predicted the presence. The parameter should be applied in all patients with suspected atrial shunt lesions where calculation of Qp:Qs is impossible.Electronic supplementary materialThe online version of this article (10.1007/s00508-020-01659-0) contains supplementary material, which is available to authorized users.

Hindbrain Herniation and Banana and Lemon Sign After Open Fetal Myelomeningocele Repair - When Do These Signs Disappear and is Shunting Predictable?

The aim was to describe the sonographic follow-up of hindbrain herniation (HH), the banana and lemon sign after fetal myelomeningocele (fMMC) repair, and the time of disappearance of these signs after the intervention, and to investigate any predictive value for the necessity of shunting during the infant's first year of life. Additionally, the sonographic evolution of the transcerebellar diameter (TCD) before and after fetal intervention was assessed. The first 50 patients that underwent fMMC repair at Zurich Center for Fetal Diagnosis and Therapy (www.swissfetus.ch) were included in this study. Sonographic scans performed weekly after fMMC repair focusing on HH and banana and lemon signs were analyzed and compared between the shunted and the non-shunted group. ROC curves were generated for the time intervals of resolution of the signs in order to show their predictive accuracy for the need for shunting until 1 year of age. HH resolved in 48 fetuses (96 %) before delivery. The sonographic disappearance of HH within the first two weeks after fMMC repair was associated with a significantly lower incidence of shunt placement (OR 0.19; 95 % CI 0.4-0.9) during the first year of life (p = 0.03). All fetuses with persistent HH before delivery received a shunt. TCD growth was observed in all fetuses. The reversibility of HH within two weeks after fMMC repair is associated with an 80 % lower incidence of shunt placement during the infant's first year of life. Moreover, it allows the cerebellum to grow and to normalize its configuration.

Cerebral monitoring during carotid endarterectomy using transcranial cerebral oximetry.

This study aimed to evaluate the outcomes of carotid endarterectomies (CEA) performed using transcranial cerebral oximetry as cerebral monitoringMETHODS: This single-center study included patients treated surgically for significant stenosis of the internal carotid artery (ICA) from January 2012 to December 2017RESULTS: Of the 654 patients, 267 were asymptomatic, and 387 were symptomatic. Eversion CEA was performed in 64.8 %, and patched conventional CEA in 35.2 % of all patients. Totally 11.4 % of all patients had a shunt inserted; all patients with the inserted shunt had the conventional pathed CEA. Severe postoperative complications occurred in 1.5 % of asymptomatic patients and 2.6 % of symptomatic patients. The stroke and death ratio in the shunted group was 2.7 %, and in the non-shunted group, 2.1 % (p = 0.7). We found no significant difference in severe postoperative complications between the shunted and non-shunted group. Further, we found the male gender (p = 0.005), coronary artery disease (p = 0.01), and ongoing smoking (p = 0.003) to be significantly associated with neurological symptoms of the ICA stenosis. We also confirmed current tobacco smoking to be significantly associated with the occurrence of postoperative stroke and death (p = 0.005)CONCLUSION: We found transcranial cerebral oximetry to be reliable in the determination of shunt insertion (Tab. 6, Ref. 26).

Dual Monitoring with Stump Pressure and Electroencephalography During Carotid Endarterectomy.

BackgroundIntraoperative monitoring during carotid endarterectomy is crucial for cerebral protection. We investigated the results of carotid endarterectomy under dual monitoring with stump pressure and electroencephalography.MethodsWe retrospectively reviewed the medical records of 50 patients who underwent carotid endarterectomy between March 2010 and February 2016. We inserted a temporary shunt if the stump pressure was lower than 35 mm Hg or if any intraoperative change was observed on electroencephalography.ResultsSeventeen (34%) patients used a temporary shunt, and the mean stump pressure was 26.8 mm Hg in the shunt group and 46.5 mm Hg in the non-shunt group. No postoperative mortality or bleeding occurred. Postoperatively, there were 3 cases (6%) of minor stroke, all of which took place in the shunt group. A comparison of the preoperative and the intraoperative characteristics of the shunt group with those of the non-shunt group revealed no statistically significant difference between the 2 groups (p <0.01).ConclusionDual monitoring with stump pressure and electroencephalography was found to be a safe and reliable monitoring method with results comparable to those obtained using single monitoring. Further study should be performed to investigate the precise role of each monitoring method.

Extracorporeal membrane oxygenator support in infants with systemic-pulmonary shunts

BackgroundManagement of a patent systemic-pulmonary (SP) shunt and the resulting runoff during extracorporeal membrane oxygenation (ECMO) varies among institutions. We have used a strategy of increased flow without surgical reduction of the shunt diameter, and here report our results with this strategy. MethodsIn this database review of 169 successive veno-arterial ECMO runs performed between 2002 and 2013 in infants and neonates, ECMO flow, time to achieve lactate clearance, normal pH, and negative fluid balance were compared in patients with shunts and those without shunts. ResultsFifty-one of 169 infants (30.2%) had a shunt in situ when ECMO was initiated. Significantly higher ECMO flows were maintained in the shunt group compared with the nonshunt group (161 ± 43 mL/kg/minute vs 134 ± 41 mL/kg/minute; P < .001). Infants with shunts had significantly higher pre-ECMO and peak lactate levels (12.4 ± 5.6 mmol/L vs 10.0 ± 6.3 mmol/L; P < .05 and 13.7 ± 4.9 mmol/L vs 11.6 ± 5.5 mmol/L; P < .02, respectively) and required a longer period of support for clearance (median, 28.8 hours [16.1-63.3 hours] vs 17.5 hours [10.8-34.5 hours]; P < .001). Although the absolute rate of lactate clearance was not significantly different between the 2 groups (median, 0.46 mmol/L/hour [0.12-0.72 mmol/L/hour] vs 0.48 mmol/L/hour [0.22-0.86 mmol/L/hour]; P = .139) the presence of a shunt, neonatal age, peak lactate, extracorporeal cardiopulmonary resuscitation, and the use of hemofiltration on ECMO significantly predicted the rate of clearance. Survival to hospital discharge was similar in the shunt and nonshunt groups (49.0% vs 48.3%; P = .932). ConclusionsA strategy of increased ECMO flow without surgically restricting shunt diameter appears to be successful in providing circulatory support in the majority of patients with an SP shunt. Equivalent survival suggests that routine surgical reduction of shunt diameter is not indicated.

Operative Factors Associated with the Development of New Brain Lesions During Awake Carotid Endarterectomy

The aim was to analyse a prospective, consecutive series of awake carotid endarterectomy (CEA) patients undergoing, when possible, pre- and postoperative diffusion-weighted magnetic resonance imaging brain scans (DWI). All CEA patients from June 23, 2006, to January 13, 2012, were prospectively entered in the study. CEA was performed under regional cervical block. Only patients demonstrating shunt dependence were shunted. Before August 7, 2008, all longitudinal endarterectomy had been performed with a vein patch. From that date all CEA were eversions without a patch, except shunted patients who were vein patched. DWI was performed 2 days before and 5 days after (3 Tesla). Scans were reported by MRI-trained radiologists. Logistic regression analysis (LRA) identified predictive variables for MRI changes using backward stepwise elimination of variables with p>.05. There was a total of 295 consecutive CEA. There were no deaths but four clinical strokes (1.4 %); 89 excluded from DWI leaving 206; of these 27 (13%) developed new DWI lesions including four of 57 (7%) in the asymptomatic group and 23 of 149 (15%) symptomatic patients. Nineteen of the 206 (9.2%) were shunted. LRA showed that shunt dependence was highly associated with new DWI lesions: odds ratio (OR) 6.43; 95% confidence interval (CI) 2.3-17.9; p<.001. Both the vein patched, non-shunted group (OR .25; CI 0.09-0.72; p=.010) and the eversion (all non-shunted and all non-patched) group (OR 0.05; CI 0.01-0.22; p<.001) were associated with a low risk of new lesions, with the eversion group a lower risk than the patched group. One in every eight CEA patients developed new DWI lesions (rate doubled in symptomatic patients). Shunt dependence in conscious CEA patients is highly associated with the development of new DWI lesions compared with non-shunted patients. For non-shunted patients the new lesion risk is low, and in those patients the risk in the eversion group is lower than in the patched group.

Right Ventricular Diastolic Performance in Children With Pulmonary Arterial Hypertension Associated With Congenital Heart Disease

Background— Right ventricular diastolic dysfunction influences outcomes in pulmonary arterial hypertension (PAH), but echocardiographic parameters have not been investigated in relation to invasive reference standards in pediatric PAH. We investigated echocardiographic parameters of right ventricular diastolic function in children with PAH in relation to simultaneously measured invasive reference measures. Methods and Results— We prospectively recruited children undergoing a clinically indicated cardiac catheterization for evaluation of PAH and pulmonary vasoreactivity testing. Echocardiography was performed simultaneously with invasive reference measurements by high-fidelity micromanometer catheter. For analysis, patients were divided into shunt and nonshunt groups. Sixteen children were studied. In the group as a whole, significant correlations were found among τ and tricuspid deceleration time, E′ , E/E′ , Time E – E ′ , A wave velocity, and global early and late diastolic strain rate. d p /d t minimum correlated significantly with late diastolic tricuspid annular velocity ( A′ ), tissue Doppler imaging–derived systolic:diastolic duration ratio, and global late diastolic strain rate. End-diastolic pressure correlated significantly with tissue Doppler imaging–derived systolic:diastolic duration ratio. On multivariate analysis, tricuspid deceleration time, Time E – E ′ , and global early diastolic strain rate were independent predictors of τ, whereas tissue Doppler imaging–derived systolic:diastolic duration ratio was an independent predictor of d p /d t minimum. In general, correlations between echocardiographic and invasive parameters were better in the shunt group than in the nonshunt group. Conclusions— Echocardiography correlates with invasive reference measures of right ventricular diastolic function in children with PAH, although it does not differentiate between early versus late diastolic abnormalities. Newer echocardiographic techniques may have added value to assess right ventricular diastolic dysfunction in this population.

EComment. Superior caval clamping without a cavoatrial shunt during bidirectional Glenn operation

We read with interest the paper by Mostafa et al. [1], in which they presented the results of two groups of single ventricle patients, who underwent bidirectional cavopulmonary anastomosis with and without a veno-atrial shunt. The authors indicate a mean venous pressure of 37.07 ± 7.12 mmHg in the non-shunted group for a mean clamp time of 9.85 ± 3.52 min. The mean intensive care unit stay was 2.57 ± 75 days in the non-shunted patients. The authors performed bidirectional Glenn operation in a cohort of patients aging between 8-108 months [1]. The superior vena cava carries at least half of the blood volume in the early periods of life [2,3]. With growth, the inferior vena cava dominates [3] and proportions become 1/3-4 in adulthood [2,3]. Thus, although superior vena cava clamping may be uneventful in later childhood or adulthood, clamping of the superior caval vein in the early periods of life may not be easily haemodynamically tolerated. The manoeuvre may lead to cardiac failure and an increased amount and number of inotropic agents may be required [2]. Moreover, although authors state the manoeuvre had not led to serious neurologic sequelae during clamping of the superior vena cava, intracerebral pressure increases and cerebral arterial flow diminishes for sure. The literature includes animal experiments of superior vena cava clamping in monkeys [4] and dogs [5]. Research indicates that temporary occlusion of the superior vena cava is safe, despite decreased cerebral blood flow during clamp application [4,5]. First of all, it seems that these experiments were performed on adult animals in both studies [4,5]. Moreover, Masuda et al. indicated histopathological changes in the basal ganglia, hippocampus and even bleeding at the frontal lobe in their experiments on monkeys [4]. Urayama et al. [5] experienced attenuated amplitudes of somatosensory evoked potentials and prolonged latency [5]. We never hesitate to perform cardiopulmonary bypass during bidirectional Glenn procedure at our institution. When an off-pump operation is planned, an external cavo-atrial shunt is created. Despite the shunt, at least 5 mcg/kg/min of dopamine facilitates the surgery. A cavo-atrial shunt with or without minimal dose of inotropic support during reconstruction of the bidirectional Glenn provides a non-adventurous procedure and is a safe technique to decompress the cerebral pressure, to minimize decrease in cerebral arterial blood flow and hence to prevent postoperative neurological events. The cannula inserted into the superior vena cava does not pose major trauma to the superior vena cava and usually does not cause venous distortion or even in case of doubt, the vein can be easily reconstructed. Conflict of interest: none declared.

A Left-to-Right Shunt via the Ductus Arteriosus Is Associated with Increased Regional Cerebral Oxygen Saturation during Neonatal Transition

Background: Oxygen delivery to the brain is dependent on cardiac output and arterial oxygen content. Objectives: The study was designed to investigate the influence of a left-to-right shunt via the ductus arteriosus (DA) on regional oxygen saturation (rSO₂) of the brain and peripheral tissue during postnatal transition. Methods: Nested case-control study. In term neonates after elective cesarian section, rSO₂ of the brain and pre- and postductal peripheral tissue were measured 15 min after uncomplicated postnatal transition. Two groups were formed according to shunt flow characteristics via the DA: shunt group (with a left-to-right shunt), and nonshunt group (no shunt). Results: Of 80 infants, in 58 (72%) a left-to-right shunt was identified, and in 22 (28%) no flow was seen via the DA. The 22 infants formed the nonshunt group. They were matched with 22 newborn infants with a left-to-right shunt via the DA (shunt group). Infants in the nonshunt group had significantly lower cerebral rSO₂ values and higher fractional tissue oxygen extraction and heart rate values. There were no significant differences in regard to peripheral rSO₂ values. Conclusion: During postnatal transition, term infants with a left-to-right shunt via the DA have significantly higher cerebral rSO₂ values compared to infants without shunt flow.

Fetal myelomeningocele surgery: preschool functional status using the Functional Independence Measure for children (WeeFIM)

To study preschool functional status in children following fetal myelomeningocele (fMMC) surgery. Prior to the NICHD-MOMS trial, 30 fMMC underwent standardized neurodevelopmental examination at 5 years of age. Functional status was determined with the Functional Independence Measure (WeeFIM), which assesses self-care, mobility, and cognitive independence. Evaluations were completed in 26 (87%). Mean cognitive (93.0 ± 21.9), self-care (66.5 ± 23.9), mobility (82.3 ± 19.5), and total (77.9 ± 20.3) functional quotient of fMMC children were significantly lower than age-matched population norms (P < 0.01). Complete caregiver independence was achieved by 22 (84%), 10 (38%), 16 (62%), and 15 (58%) fMMC children for cognition, self-care, mobility, and total functional outcome, respectively. Cognitive, mobility, and total independence were higher in non-shunted than shunted fMMC children (P = 0.02, P = 0.02, and P < 0.01, respectively) and in fMMC children with average neurodevelopmental scores (P < 0.001, P = 0.01, and P < 0.01, respectively). Self-care independence tended to be higher in the non-shunted group and in fMMC children with normal neurodevelopmental outcome (P = 0.07 and P = 0.09, respectively). The majority of fMMC children achieved cognitive and mobility independence, but continue to require significant assistance in self-care. Non-shunted and fMMC children with normal neurodevelopmental outcome were more likely to be independent in daily living activities. Better understanding of the extent of functional limitations following fMMC surgery will allow for more effective early interventions geared toward maximizing independence in everyday tasks in all environments.

Cerebral monitoring in patients undergoing carotid endarterectomy using a triple assessment technique

Selective shunting during carotid endarterectomy (CEA) is advocated to reduce shunt related stroke. Cerebral monitoring is essential for temporary carotid shunting. Many techniques are available for cerebral monitoring, however, none is superior to monitoring the patient's neurological status (awake testing) while performing the procedure under local anaesthesia (LA). Cerebral oximetry (CO) and trans-cranial Doppler (TCD) has previously been used to show the adequacy of cerebral circulation in patients undergoing CEA. The aim of this study is to assess the reliability of CO and TCD in predicting the need for shunting compared to the awake testing. Patients scheduled for CEA under LA were included. Patients converted to general anaesthesia (GA) and patients with no TCD window were excluded from the study. The Somanetics INVOS(®) CO was used for ipsilateral cerebral monitoring in all patients, in addition to TCD and awake testing. The percentage fall in CO regional oxygen saturation (rSO(2)), and decline in the mean flow velocity (FVm) in TCD following carotid artery clamping recorded. A drop in rSO(2) of ≥20% or FVm of ≥50% was considered an indicator of cerebral ischaemia that may predict the need for carotid shunting. Patients only shunted based on awake testing. Forty-nine patients underwent triple assessment. The median clamp time was 24 min. 8/49 patients (16.3%) needed carotid shunting based on awake testing. In this group, six patients had ≥20% drop in rSO(2), and ≥50% drop in FVm. However, two patients had a non-significant drop in both rSO(2) and FVm (false negative). In the non-shunted group (41/49), one patient had a significant drop in rSO(2) (false positive) while 10/41 patients had a >50% drop in FVm. This represents sensitivity of 75%, and specificity of 97.5% for CO compared to sensitivity of 75% and specificity of 75% for TCD in prediction of shunting. The positive predictive value and negative predictive value were 85.7 and 95.2%, respectively for CO, compared to 37.5 and 93.9% for TCD. TCD is less accurate than CO in predicting the need for carotid shunting during CEA. A combination of both methods does not add to the accuracy of detecting the need for carotid shunting.

Leukoaraiosis Predicts the Need for Intraoperative Shunt Placement During Carotid Endarterectomy

White matter hyperintense lesions (WMHLs) are related to age, hypertension, and ischemia. They increase the risk of stroke in natural history and perioperatively during carotid endarterectomy. This may reflect an association with impaired cerebral hemodynamics. Hence, the authors studied whether ipsilateral WMHLs predict shunt requirement on clamping as an indicator of hemodynamic compromise. A retrospective analysis was done in patients with symptomatic and severe carotid stenosis (>60%). Ipsilateral WMHL volumes were calculated from magnetic resonance imaging scans and association studied with the requirement of an intraoperative shunt. Seventy patients were included. Twelve (17%) patients required shunting and 2 developed perioperative strokes. Patients requiring shunting had a larger WMHL volume (adjusted means = 16.2 +/- 2.9 mL compared with 8.7 +/- 1.2 mL for the nonshunt group; P = .020). Ipsilateral WMHL volume is a significant predictive factor for shunt requirement during carotid endarterectomy. This may reflect cerebral hemodynamic compromise.

Functional gait comparison between children with myelomeningocele: shunt versus no shunt

The aim of this study was to compare functional gait differences between patients with myelomeningocele (MM) who have a ventriculoperitoneal shunt (VPS) with those who do not. Our analyses were adjusted for confounding by age, lesion level, orthotic use, and assistive device use. The Functional Mobility Scale (FMS) was used to compare the shunted group (n=98; 60 males, 38 females; mean age 10y 2mo [SD 3y 11mo]; 73 sacral/19 low lumber/six high lumbar lesion level) with the non-shunted group (n=63; 32 males, 31 females; mean age 9y 11mo [SD 3y 11mo]; 45 sacral/12 low lumber/six high lumbar lesion level). Participants with a shunt had lower FMS 500 and FMS 50 scores compared with participants without a shunt; hence the participants without a shunt were more independent in their ambulation at medium and longer distances. For a subset of participants who underwent a three-dimensional gait analysis, we also collected temporal-spatial gait parameters (velocity, cadence, and stride length). Our results show that participants with MM and no shunt who underwent gait analysis(11 males, 10 females; mean age 9y 6mo [SD 4y]; 15 sacral/6 low lumber/0 high lumbar lesion level) tend to walk at a significantly greater velocity and stride length as compared with those with a shunt (33 males, 18 females; mean age 10y [SD 4y]; 38 sacral/13 low lumber/zero high lumbar lesion level). These data allow the treatment team to present more specific information regarding functional ambulatory expectations to patients with MM and their families.

Effect of maternal dexamethasone treatment on the type II pneumocytes in hypoplastic lung by oligohydramnios: an ultrastructural study

A previous study documented the effects of maternal corticosteroid treatment on structural growth and functional development in fetal lungs associated with pathogenic conditions such as oligohydramnios using immunohistochemical and morphometric analyses. The purpose of the present study was to examine the effect of maternal dexamethasone treatment the expression of lamellar body in type II pneumocytes of the fetal rabbit lungs with hypoplasia induced by oligohydramnios using electron microscopy. Using an amniotic shunting rabbit model, pregnant rabbits were injected intravenously with either 0.1 ml of saline or 0.25 mg/kg/day of dexamethasone in 0.1 ml of saline 48 and 24 h before the delivery of fetuses, at day 30 of gestation. The number of lamellar bodies per type II pneumocyte was counted in each group using electron micrographs. The number of lamellar bodies per type II pneumocyte in the lungs of the shunted group that received saline was consistently and significantly less than that of the other three groups (5.49 +/- 2.07 vs. 7.34 +/- 2.27: shunted group that received dexamethasone, 7.58 +/- 2.08: non-shunted group that received saline, 7.79 +/- 1.90: non-shunted group that received dexamethasone; P < 0.01). These results suggest that maternal dexamethasone treatment accelerates the maturation of the surfactant system, especially the expression of lamellar bodies in type II pneumocytes, even in hypoplastic lungs induced by oligohydramnios.

Neuronal damage in hydrocephalus and its restoration by shunt insertion in experimental hydrocephalus: a study involving the neurofilament-immunostaining method

The morphological and functional impairments of neurons and their connections caused by hydrocephalus, and their restoration by ventricular shunt placement were investigated in experimental hydrocephalus by the immunostaining of neurofilaments, which constitute the major component of the neuronal cytoskeleton. Progressive hydrocephalus was induced in 15 young mongrel dogs 1 to 2 months of age, 3 to 4 weeks after cisternal injection of kaolin. The dogs were divided into three groups of five animals each, a "preshunt," "post-shunt," and "nonshunt" group, depending on whether the hydrocephalic animals underwent a procedure to insert a ventriculoperitoneal shunt. Neurofilament, glial fibrillary acid protein (GFAP), and synaptophysin immunostaining were performed using samples of brain tissue from each hydrocephalic group and a fourth "control" group (five animals). In the cortex, morphological deformation and heterogeneous neurofilament immunoreactivity of the apical dendrites became pronounced in accordance with the progression of hydrocephalus (from the preshunt to the nonshunt group), and these changes remained after shunt insertion (postshunt group). In the periventricular white matter, swollen and fragmented axons increased in number along with hydrocephalic progression and were incompletely repaired by ventricular shunt placement. The GFAP-positive astrocytes observed around repaired axons in the postshunt group were seen more prominently than in the untreated hydrocephalic groups. In the internal capsule, fairly good recovery from axonal damage caused by the hydrocephalic condition was achieved by insertion of a ventricular shunt, compared with that seen in the periventricular white matter. Cytoskeletal damage of neurons in hydrocephalus and its incomplete restoration by shunt placement were most significant in the periventricular white matter. This finding may account for the impaired cognitive function seen in children who have shunts and an apparently reconstituted cerebral mantle; therefore, neuronal protection in the early hydrocephalic state should be considered.

QEEG Changes During Carotid Clamping in Carotid Endarterectomy: Spectral Edge Frequency Parameters and Relative Band Power Parameters

Intraoperative monitoring is needed to identify accurately those patients in need of a shunt during carotid endarterectomy. EEG can be used for this purpose, but there is no consensus on the variables to use. Using a database consisting of 149 EEGs recorded from patients during carotid endarterectomy under isoflurane (n=61) or propofol (n=88) anesthesia and who did or did not receive a shunt, the authors investigated which of 16 derivations (common reference, Cz) and 12 parameters (relative and absolute powers and spectral edge frequencies [SEFs]) singly or in combination could best distinguish between the shunt and the nonshunt groups for the two anesthesia regimens. Receiver operating characteristic curves were used to select derivation/parameter combinations for three types of trend computation: (1) values of relative powers and SEFs during clamping (C) only, (2) clamp minus preclamp (baseline) differences (C-B), and (3) C-B differences in absolute logarithmic power (DeltalogP). For both anesthesia regimens, C-B computation distinguished best between the shunt and nonshunt groups. For isoflurane anesthesia, SEF parameters were the best, and for propofol anesthesia the relative power parameters. Discriminant analysis, in which additional derivation/parameter combinations were added, increased the discriminative power of the DeltalogP computation but not of the C or C-B computations. For isoflurane anesthesia, SEF 90% was the best single parameter for distinguishing between patients who did and did not need a shunt and the four best derivations were F3-Cz, P4-Cz, C4-Cz, and F7-Cz. For the propofol anesthesia, the relative power (C or C-B computations) of the delta band was the best and the four best derivations were F8-Cz, T4-Cz, C4-Cz, and F4-Cz.