Structural damage burden and hypertrophic olivary degeneration in pediatric postoperative cerebellar mutism syndrome

Cerebellar mutism syndrome (CMS) occurs in one out of four children after posterior fossa tumor surgery, with open questions regarding risk factors, pathophysiology, and prevention strategies. Because of similarities between several cerebellar syndromes, a common pathophysiology with damage to the dentato-thalamo-cortical and dentato-rubro-olivary pathways has been proposed. Hypertrophic olivary degeneration (HOD) is an imaging correlate of cerebellar injury observed for instance in stroke patients. Aim of this study was to investigate whether the occurrence and severity of CMS correlates with the extent of damage to the relevant anatomical structures and whether HOD is a time-dependent postoperative neuroimaging correlate of CMS. We performed a retrospective single center study of CMS patients compared with matched non-CMS controls. CMS occurred in 10 children (13% of the overall cohort) with a median age of 8 years. Dentate nucleus (DN) injury significantly correlated with CMS, and superior cerebellar peduncle (SCP) injury was associated by tendency. HOD was observed as a dynamic neuroimaging phenomenon in the postoperative course and its presence significantly correlated with CMS and DN injury. Children who later developed HOD had an earlier onset and tended to have longer persistence of CMS. These findings can guide surgical measures to protect the DN and SCP during posterior fossa tumor resections and to avoid a high damage burden (i.e., bilateral damage). Development of intraoperative neuromonitoring of the cerebellar efferent pathways as well as improved preoperative risk stratification could help to establish a patient-specific strategy with optimal balance between degree of resection and functional integrity.

     

Continuous, on-line, real-time measurement of cardiac output and derived cardiorespiratory variables in the critically ill

A previously reported monitoring system provided continuous direct measurements of oxygen consumption and intravascular pressures. These data were combined with interval measurements of cardiac output and blood oxygen saturations to derive various hemodynamic and oxygen transport variables. This system has now been modified so that cardiac output is measured continuously in real-time.     

Retrospective consideration of the incidence of anaphylactoid reactions following administration of Plasmasteril and Longasteril]

The frequency of anaphylacotid reactions following the infusion of colloidal volume substitutes has become more transparent in the recent years due to retrospective reports of several hospitals and especially by a prospective multi-clinical study carried out in the Bavarian area. As a contribution towards medicament safety by the manufacturers of infusion solutions, a quantitation of the incidents should be tried. For the period January 1974-June 1977 Dr. E. Fresenius KG has compared the units sold of HES (Plasmasteril) and Dextran 75 (Longasteril 75) with the reported incidents. The frequency of severe anaphylactoid reactions (type III + IV) amounted to 19/458 924 = 0.0041% for Dextran 75 and to 2/550 350 = 0.0004% for hydroxyethyl starch. The frequency of life-threatening incidents with HES proved to be lower than for Dextran 75 by the factor 10.     

Mathematical decription of the human intravascular elimination of HAS after repeated infusions]

Serum concentrations of high molecular weight-hydroxyethyl starch (HMW-HES, Mw 450,000 d, Mn 71,000 d, Mw/Mn = 6.3, MS = 0.7) were determined in normovolemic subjects dosed with three consecutive daily 500 ml infusions, to mathematically calculate the influence of the two-variable (Mw and MS) HES drug design system, on elimination of this material from the intravascular space under controlled conditions. Following the initial 500 ml (6% solution) infusion, the intravascular clearance up to 24-hours post-injection, was well predicted by the exponential equation: y = 3.94 + 3.34e-0.15x. On days two and three, the clearances up to 24-hours post-injection, were described by the equations: y = 6.32 + 3.75e-0.15x and y = 9.39 + 5.41e-0.15x, respectively. From these mathematical models, it appears that up to 24-hours post-injection on each of the three infusion days, HMW-HES is cleared from the bloodstream in a similar manner. HMW-HES clearance from the blood on day three, however, exhibited a slightly faster rate of decline, as seen by the larger coefficient attributed to the exponential component. The serum concentration of HMW-HES, 480 hours (2.9 weeks) following the third and final infusion, was 2.3 +/- 0.3 (SD) mg ml-1. Thus, in the 480-hour interval following the third and final injection, the serum concentration of HMW-HES measured at 10 minutes after injection 3, had been reduced by 85%. This decline in serum concentration following the infusion of HMW-HES, appears to be greater than previously reported by other investigators.     

Role of ventriculoperitoneal shunt valve design in the treatment of pediatric hydrocephalus—a single center study of valve performance in the clinical setting

Purpose

Previous studies have established risk factors for ventriculoperitoneal shunt failure in children. However, the role of valve type as a determinant of complications and outcome remains unclear. The aim of this study was to compare the fixed-pressure paediGAV and the programmable Codman Hakim valves in the clinical setting.

Methods

We conducted a retrospective review of patients younger than 16 years who underwent primary implantation of a ventriculoperitoneal shunt with either valve type at our institution between January 2005 and December 2010. Shunt survival analyses were performed to identify variables associated with risk of shunt failure.

Results

Of the 44 patients in the paediGAV cohort, 50 % reached the endpoint of shunt failure with a mean time to shunt failure of 7 months. The Codman Hakim cohort comprised 29 patients, of which 55 % experienced shunt failure with a mean time to shunt failure of 8 months. Stratified analyses identified young age at implantation and posthemorrhagic hydrocephalus as risk factors for shunt failure. Shunt survival analysis revealed no significant difference with regard to valve type.

Conclusions

This study confirmed important risk factors for shunt failure in children. Despite certain limitations and biases, similar findings for both valves examined in the clinical setting were obtained. Thus, valve type does not seem to influence risk of shunt failure. Prospective, randomized, and controlled trials are required to validate these results.     

Reactions of critically ill patients to volume therapy with hydroxyethyl starch (6% HES 450/0.7)

At 31 critically ill surgical patients who on clinical grounds required fluid therapy, hemodynamic and oxygen transport, responses were measured after volume expansion with 500 ml 6% HES 450/0,7. There were statistically significant increases in cardiac index (CI) from 3,5 +/- 2,1 to maximal values of 4,4 +/- 0,2 (l/min/m2) and in wedge pressure (WP) from 9,3 +/- 0,7 to maximal values of 13,6 +/- 0,8 (mm Hg) and a significant reduction of systemic vascular resistance index (SVRI) from 2018 +/- 128 to 1641 +/- 102 (dynsec/cm5 m2). There were also observed statistically significant maximal increases of left ventricular stroke work index (LVSWI) from 41 +/- 3,1 to 53 +/- 3,2 (gm/m2) of oxygen delivery (DO2) from 489 +/- 24 to 587 +/- 29 (ml/min/m2) and of oxygen consumption (VO2) from 111 +/- 6 to 130 +/- 7 (ml/min/m2) which took place at the time of the maximum CI-increase. Moreover MAP-, CI- and VO2-responses of patients were stratified according to clinical conditions like time of operation, age, prognosis, ARDS, sepsis, hyperdynamic- and blood volume status.     

Genetic predisposition favors the acquisition of stable artemisinin resistance in malaria parasites

The emergence of artemisinin-resistant Plasmodium falciparum malaria jeopardizes efforts to control this infectious disease. To identify factors contributing to reduced artemisinin susceptibility, we have employed a classical genetic approach by analyzing artemisinin responses in the F1 progeny of a genetic cross. Our data show that reduced artemisinin susceptibility is a multifactorial trait, with pfmdr1 and two additional loci (on chromosomes 12 and 13) contributing to it. We further show that the different artemisinin susceptibilities of the progeny strains affect their responses to selection with increasing concentrations of artemisinin. Stable, high-level in vitro artemisinin resistance rapidly arose in those parasites that were the least artemisinin susceptible among the F1 progeny, whereas progeny that were highly artemisinin susceptible did not acquire stable artemisinin resistance. These data suggest that genetic predisposition favors the acquisition of high-level artemisinin resistance. In vitro-induced artemisinin resistance did not result in cross-resistance to artesunate or artemether, suggesting that resistance to one derivative does not necessarily render the entire drug class ineffective.     

Tolerance of awake surgery for glioma: a prospective European Low Grade Glioma Network multicenter study

Background

Gross total removal of glioma is limited by proximity to eloquent brain. Awake surgery allows for intraoperative monitoring to safely identify eloquent regions. However, data on adverse psychological effects induced in these patients is limited.

Objective

This study explored patients’ perception of awake surgery for glioma, with special focus on intraoperative pain and anxiety.

Methods

This study was conducted at five neurosurgical centers within the European Low Grade Glioma Network. Patients underwent awake surgery for glioma according to the protocol of the individual center. Pain and discomfort were measured during the awake phase. Postoperatively, patients answered a questionnaire on aspects of their operation.

Results

One hundred five patients were enrolled. Pain levels on a 10-cm visual analogue scale were 1.3 cm at the beginning, 1.9 cm the middle, and 2.1 cm at the end of awake phase. Levels of anxiety were 2.2 cm, 2.5 cm and 2.6 cm, respectively. Women and patients younger than 60 years exhibited highest mean anxiety levels. The patient questionnaire revealed that the majority of patients feel comfortable with the procedure. Discomfort resulted from head fixation or positioning on the operating table.

Conclusions

We demonstrate that awake surgery is well tolerated, as neither intraoperative nor postoperative assessment revealed major disadvantages. Concerning practical lessons learned from this study, we emphasize the importance of minimizing pain and preparing patients thoroughly to reduce anxiety and maximize cooperation. Awake surgery is an excellent treatment modality for brain tumors with very positive perception by patients.