ABSTRACT
Objective To evaluate the impact of positive end-expiratory pressure (PEEP) on hemodynamic variables including central venous pressure (CVP),mean arterial pressure (MAP) and heart rate (HR) in patients with central respiratory failure treated by mechanical ventilation.Methods Thirty two neurosurgical patients with central respiratory failure,male 19,female 13,mean age (58.8 ± 13.9)years,GCS ≤ 8 points,were enrolled in this prospective,self-control study between June 1,2009,and May 31,2011.Patients were excluded in cases of severe cardiopulmonary disorders,pericardial diseases,person machine confrontation,administration of vasoactive drugs,and hypervolemia or hypovolemia.On admission to neurosurgical intensive care unit,all patients were mechanically ventilated in the mode of synchronized intermittent mandatory ventilation.Hemodynamic effects of six randomly set levels of end-expiratory pressures (0,3,6,9,12,15 cm H2O,every 10 min,1cm H2O =0.098 kPa) were studied in all patients.CVP,MAP and HR were recorded at each of the six end-expiratory pressure levels.One-way analysis of variance and simple linear regression model were used for data analysis.Results The levels of central venous pressure were elevated with increase in end-expiratory pressures.CVP levels were positively correlated with the levels of PEEP (R =0.468,P =0.000),with a simple linear regression equation expressed as:CVP (cm H2O) =7.870 +0.344 ×PEEP (cm H2O),The levels of MAP showed no statistically significant changes at different PEEP levels (F =1.390,P =0.227).No linear correlation between MAP,HR and PEEP levels was found (R =0.042 and 0.160,P =0.413 and 0.002).Conclusions CVP values would be overestimated during mechanical ventilation at different PEEP levels in mechanically ventilated patients due to central respiratory failure,positive correlation existed between CVP values and PEEP levels,whereas MAP was unaffected by different PEEP levels.This study could probably offer a quantitative reference for correct assessment of such a hemodynamic variable as CVP for mechanically ventilated patients without discontinuance of PEEP.Further studies are needed to determine whether these findings could be confirmed in a prospective manner.
ABSTRACT
Objective To discuss the reasons of false judgments of localization of the rupture aneurysms and find the way to fix this problem in patients with multiple intracranial aneurysms. Methods The clinical data of 25 consecutive patients, who presented with their first spontaneous subarachnoid hemorrhage and had multiple intracranial aneurysms from 2003 to 2009 in our hospital, were analyzed retrospectively. The rupture aneurysms were determined according to Nehls' method that reported before, and the supposed responsible rupture aneurysms w0ere clipped within 48 hours after hemorrhage in all patients. More aneurysms that could not be accessed in the same surgical session were surgically terated later. Results The location of the rupture aneurysm was verified at the time of surgery in all 25 patients. The concordance rate of the prediction and the reality of the rupture aneurysm was 80% (20/25). Four patients ( 16% ) ,in whom the ruptured aneurysm was not correctly identified,rebled after surgery,and 2 patients died as a result of the rebleeding One patients had no clear diagnosis at the end. Conclusion In the reported cases, about 80% rupture aneurysms could be correctly diagnosed before treatment according to the CT and DSA examinations. If clear diagnosis couldn't be made,additional examinations should be considered, such as CTA or MRI. Rupture aneurysms must be confirmed during the operation and the other aneurysms should be checked to exclude additional responsible aneurysms in all cases.
ABSTRACT
Objective To evaluate the effect of computer-aided design of composite materials with epoxide acrylate maleic (E) and hydroxyapatite (H) in cranioplasty. Methods A total of 45 patients with cranium defects were treated with cranioplasty by using skull bone flaps made of composite materials including epoxide acrylate maleic (E) and hydroxyapatite (H) ,which was designed with computer aid according to individual requirements. The patients were followed up for 6-36 months. Results After cranioplasty with composite EH, there occurred subcutaneous fluid in one patient and mild bone collapse in one. The composite EH showed good histocompatibility, with no infection or rejection. Conclusion During cranioplasty, use of computer-aided design of composite EH takes advantages of good accuracy, short operation time, good biocompatibility and good clinical efficiency.