Use of hypertonic saline solutions in treatment of cerebral edema and intracranial hypertension

OBJECTIVES: To review the literature on the use of hypertonic saline (HS) in treating cerebral edema and intracranial hypertension. DATA SOURCES: Review of scientific and clinical literature retrieved from a computerized MEDLINE search from January 1965 through November 1999. STUDY SELECTION: Pertinent literature is referenced, including clinical and laboratory investigations, to demonstrate principles and efficacy of treatment with HS in patients with intracranial space-occupying pathology. DATA EXTRACTION: The literature was reviewed to summarize the mechanisms of action, efficacy, adverse effects, systemic effects, and comparisons with standard treatments in both clinical and laboratory settings. DATA SYNTHESIS: HS has an osmotic effect on the brain because of its high tonicity and ability to effectively remain outside the bloodbrain barrier. Numerous animal studies have suggested that fluid resuscitation with HS bolus after hemorrhagic shock prevents the intracranial pressure (ICP) increase that follows resuscitation with standard fluids. There may be a minimal benefit in restoring cerebral blood flow, which is thought to be mitigated through local effects of HS on cerebral microvasculature. In animal models with cerebral injury, the maximum benefit is observed in animals with focal injury associated with vasogenic edema (cryogenic injury). The ICP reduction is seen for < or =2 hrs and may be maintained for longer periods by using a continuous infusion of HS. The ICP reduction is thought to be caused by a reduction in water content in areas of the brain with intact blood-brain barrier such as the nonlesioned hemisphere and cerebellum. Most comparisons with mannitol suggest almost equal efficacy in reducing ICP, but there is a suggestion that mannitol may have a longer duration of action. Human studies published to date reporting on the use of HS in treating cerebral edema and elevated ICP include case reports, case series, and small controlled trials. Results from studies directly comparing HS with standard treatment in regard to safety and efficacy are inconclusive. However, the low frequency of side effects and a definite reduction of ICP observed with use of HS in these studies are very promising. Systemic effects include transient volume expansion, natriuresis, hemodilution, immunomodulation, and improved pulmonary gas exchange. Adverse effects include electrolyte abnormalities, cardiac failure, bleeding diathesis, and phlebitis. Although unproven, a potential for central pontine myelinolysis and rebound intracranial hypertension exists with uncontrolled administration. CONCLUSIONS: HS demonstrates a favorable effect on both systemic hemodynamics and intracranial pressure in both laboratory and clinical settings. Preliminary evidence supports the need for controlled clinical trials evaluating its use as resuscitative fluid in brain-injured patients with hemorrhagic shock, as therapy for intracranial hypertension resistant to standard therapy, as firstline therapy for intracranial hypertension in certain intracranial pathologies, as small volume fluid resuscitation during spinal shock, and as maintenance intravenous fluid in neurocritical care units.     

Complications,outcomes, and need for fusion after minimally invasive posterior cervical foraminotomy and microdiscectomy

Background context

Posterior cervical foraminotomy (PCF) with or without microdiscectomy (posterior cervical discectomy [PCD]) is a frequently used surgical technique for cervical radiculopathy secondary to foraminal stenosis or a laterally located herniated disc. Currently, these procedures are being performed with increasing frequency using advanced minimally invasive techniques. Although the safety and efficacy of minimally invasive PCF/PCD (MI-PCF/PCD) have been established, reports on long-term outcome and need for secondary surgical intervention at the index or adjacent level are lacking.

Purpose

To determine the rates of complications, long-term outcomes, and need for secondary surgical intervention at the index or adjacent level after MI-PCF and microdiscectomy.

Study design

Retrospective analysis of a prospective cohort.

Patient sample

Seventy patients treated with MI-PCF and/or MI-PCD for cervical radiculopathy.

Outcome measures

Visual Analog Scale for neck/arm (VAS_N/A) pain and Neck Disability Index (NDI).

Methods

Ninety-seven patients underwent MI-PCF with or without MI-PCD between 2002 and 2011. Adequate prospective follow-up was available for 70 patients (95 cervical levels). The primary outcome assessed was need for secondary surgical intervention at the index or adjacent level. The secondary outcomes assessed included complications and improvements in NDI and VAS_N/A scores. All complications were reviewed. Mixed-model analyses of variance with random subject effects and autoregressive first-order correlation structures were used to test for differences among NDI, VAS_A, and VAS_N measurements made over time while accounting for the correlation among repeated observations within a patient. All statistical hypothesis tests were conducted at the 5% level of significance.

Results

Patients were followed for a mean of 32.1 months. Of 70 patients operated, there were 3 (4.3%) complications (1 cerebrospinal fluid leak, 1 postoperative wound hematoma, and 1 radiculitis), none of which required a secondary operative intervention. Five patients required an anterior cervical discectomy and fusion (eight total levels fused) on average 44.4 months after the index surgery. Of those, five (5.3%) were at the index level and three (2.1%) were at adjacent levels. Neck Disability Index scores improved significantly (p<.0001) immediately postoperatively and continued to decrease gradually with time. Visual Analog Scale for neck/arm scores improved significantly (p<.0001) from baseline immediately postoperatively but tended to plateau with time.

Conclusions

Minimally invasive PCF with or without MI-PCD is an excellent alternative for cervical radiculopathy secondary to foraminal stenosis or a laterally located herniated disc. There is a low rate (1.1% per index level per year) of future index site fusion and a very low rate (0.9% per adjacent level per year) of adjacent-level disease requiring surgery.     

Guidewire pacing during transcatheter aortic valve implantation in a patient with complex congenital heart disease

We present a case of temporary guidewire pacing in a patient with Fontan anatomy during transcatheter aortic valve implantation. Temporary pacing was successfully achieved utilizing this method without complications. There is an increasing population of patients with complex congenital heart disease and expanding variety of transcatheter interventions. Due to limitations in vascular access and surgical anatomies, guidewire pacing may have a wide array of potential applications in pediatrics and the congenital heart disease population.     

Doppler echocardiographic evaluation of pulmonary artery flow after modified Fontan operation: importance of atrial contraction

Doppler echocardiography was used to evaluate blood flow in the pulmonary artery in 14 patients 2 to 42 months (mean (SD) 17 (12) months) after a modified Fontan operation incorporating a direct atriopulmonary anastomosis. Preoperatively six patients had tricuspid atresia, six had a double inlet left ventricle, and two had pulmonary atresia with an intact ventricular septum. The postoperative rhythm was sinus in 11 patients, junctional in one, ventricular pacing in one, and atrioventricular sequential pacing in one. In one patient the Doppler trace was unsatisfactory for analysis. In all patients forward flow in the pulmonary artery had biphasic peaks related to both atrial and ventricular contraction. The mean (SD) peak flow velocity that was synchronous with atrial contraction was 80 (30) cm/s and that synchronous with ventricular contraction was 74 (23) cm/s. The atrial contribution to total pulmonary artery flow, assessed by velocity-time integrals, varied between 22% and 73% (mean (SD) 45 (14)%). In patients with tricuspid atresia the mean (SD) peak flow velocity with atrial contraction was 90 (27) cm/s and that with ventricular contraction was mean (SD) 68 (24) cm/s. In patients with double inlet left ventricle the mean (SD) peak flow velocity was 67 (36) cm/s with atrial contraction and 80 (25) cm/s with ventricular contraction. The atrial contribution to total pulmonary blood flow in patients with tricuspid atresia was significantly higher (53 (11)%) than in those with double inlet left ventricle (37 (14)%). Pulmonary artery flow after modified Fontan operation was biphasic and was related to both atrial and ventricular contraction. The atrial contribution to pulmonary blood flow is greater in patients with tricuspid atresia than in those with a double inlet left ventricle. The mechanism of the second peak related to ventricular contraction is unknown.     

Noncirrhotic portal fibrosis/idiopathic portal hypertension: APASL recommendations for diagnosis and treatment

The Asian Pacific Association for the Study of the Liver (APASL) Working Party on Portal Hypertension has developed consensus guidelines on the disease profile, diagnosis, and management of noncirrhotic portal fibrosis and idiopathic portal hypertension. The consensus statements, prepared and deliberated at length by the experts in this field, were presented at the annual meeting of the APASL at Kyoto in March 2007. This article includes the statements approved by the APASL along with brief backgrounds of various aspects of the disease.     

Pulmonary regurgitation in transposition of the great arteries.

A female infant who presented with cyanosis and tachypnoea was found to have transposition of the great arteries, a ductus arteriosus, and a ventricular septal defect. An aortogram showed evidence of mild pulmonary regurgitation, which persisted after a Senning's operation; this is a hitherto unrecognised clinical finding.     

Variation management by functional tolerance allocation and manufacturing process selection

The imperfections of the manufacturing process lead to functional characteristics degradation, and therefore product quality. To ensure a certain level of product quality, the synthesis of tolerance (tolerance design) aims to determine the acceptable limits of the characteristics of parts, assemblies... The allocation or synthesis of functional tolerances is an important step in the design process which takes place generally during the detailed design and greatly impacts the design of the manufacturing process, manufacturing and product control. That is why it is important, when functional tolerances are quantified, to take into account their impacts on the manufacturing cost and product quality. These two concepts (manufacturing cost and product quality) are usually considered as conflicting goals. The proposed approach aims to allocate the functional tolerances that provide the best ratio between functional performances and manufacturing cost. It is based on the “Key Characteristics” approach, developed by Boeing coupled with an activities approach. This optimization is carried out by a genetic algorithm. The process selection is performed by a constraint satisfaction algorithm. Finally, the impacts of process choices are assessed with the Monte Carlo simulation which calculates the behavior and quality of the resulting product.     

Epigenetic Mechanisms Underlying the Pathogenesis of Neurogenetic Diseases

There have been considerable advances in uncovering the complex genetic mechanisms that underlie nervous system disease pathogenesis, particularly with the advent of exome and whole genome sequencing techniques. The emerging field of epigenetics is also providing further insights into these mechanisms. Here, we discuss our understanding of the interplay that exists between genetic and epigenetic mechanisms in these disorders, highlighting the nascent field of epigenetic epidemiology—which focuses on analyzing relationships between the epigenome and environmental exposures, development and aging, other health-related phenotypes, and disease states—and next-generation research tools (i.e., those leveraging synthetic and chemical biology and optogenetics) for examining precisely how epigenetic modifications at specific genomic sites affect disease processes.     

High Risk of New Episode of Symptomatic Vasospasm in Unaffected Arteries in Subarachnoid Hemorrhage Patients Receiving Targeted Endovascular Treatment for Symptomatic Focal Vasospasm

Background

There is controversy whether asymptomatic vasospasm in other arteries should be concurrently treated (global treatment) in patients receiving targeted endovascular treatment [percutaneous-transluminal-angioplasty (PTA) and/or intra-arterial (IA) vasodilators] for focal symptomatic vasospasm.

Objective

To determine the rates of occurrence of new symptomatic vasospasm in previously asymptomatic arterial distributions among patients with aneurysmal subarachnoid hemorrhage (SAH) who underwent targeted endovascular treatment for focal symptomatic vasospasm.

Methods

We identified all patients with SAH who had received targeted endovascular treatment during a 4-year period. We ascertained any new occurrence of symptomatic vasosopasm requiring endovascular treatment in previously unaffected (and untreated) arterial distributions within the same hospitalization. Blinded reviewers quantitatively graded angiographic vasospasm (<25, 26–49, ≥50 %) in all major arteries for each patient at the time of targeted treatment.

Results

Of the 41 patients who received targeted endovascular treatment (PTA in 41 % and vasodilators in 59 %), 11 (27 %) developed new symptomatic vasospasm in previously asymptomatic vascular distributions requiring endovascular treatment. Moderate severity of angiographic vasospasm in asymptomatic arteries at the time of targeted treatment tended to predict the occurrence of new symptomatic vasospasm. The rate of death and disability at discharge [modified Rankin scale (mRS) of 3–6] was 82 % (9/11) among those who developed a new episode of symptomatic vasospasm compared with 70 % (21/30) in those who did not (P = 0.58).

Conclusions

High risk of new occurrence of ischemic symptoms in previously asymptomatic (and untreated) arterial distributions among patients receiving targeted treatment should be recognized. Further studies should evaluate the benefit of performing global endovascular treatment during the initial targeted endovascular treatment session.