[Syndromes of overdrainage of ventricular shunting in childhood hydrocephalus]

Overdrainage in ventricular shunting constitutes a difficult to prevent and to treat complication. The authors reviewed a retrospective series of 512 children submitted to a ventricular shunting procedure aimed at analysing factors influencing this type of complication. The causes for the hydrocephalus were congenital (n=172), post-myelomeningocele (n=123), posthemorrhagic (n=103), tumoral (n=64), postmeningitis (n=40) and posttraumatic (n=10). Eighty-eight children (17.8%) evolved with a complication related to the excessive function of the valve. The authors investigated the relationship between hydrocephalus' etiology and type of overdrainage syndromes. The most frequent complication was ventricular catheter block (n=50), followed by symptomatic slit ventricle syndrome (SVS) (n=19), subdural hematoma (n=10) and trapped fourth ventricle (n=9). There were no statistical differences regarding complications for each etiologic subset of hydrocephalus. SVS occurred in 19 children (3.71%), a low rate according to the current literature. Posthemorrhagic and postinfectious hydrocephalus grouped together showed a higher rate of SVS (p=0.005), a feature that we attributed to the cerebral destruction caused by these two conditions. Treatment of SVS was complex and required diverse procedures, applied in an escalated way, which included five decompressive craniectomies. The authors suggest avoiding, as much as possible, the use of ventricular shunts, and recommend the alternative use of new technology valves and neuroendoscopic procedures.

[Is the predischarge exercise test valid in patients younger than 40 years old after myocardial infarct for determination of multivascular disease?]

BACKGROUND AND OBJECTIVES

Conventional exercise testing before hospital discharge is the most useful procedure in order to estimate postinfarction prognosis and in detecting multivessel coronary disease which is associated with a poor long-term prognosis. There are no bibliographic reports about it in younger myocardial infarction survivors. The aim of the study was to evaluate sensitivity, specificity and predictive value of symptoms limited maximal exercise testing for multivessel disease diagnosis in young patients after myocardial infarction.

METHODS

Myocardial infarction survivors until the age of 40 performed symptoms limited maximal exercise testing and had a coronary arteriography before hospital discharge.

RESULTS

A total of 100 consecutive patients were included, although in only 83 of them exercise tests and coronariographic studies were done. In this group, multivessel disease was confirmed in 27 patients (15 with positive tests and 12 with normal exercise testing). In the remaining 56 young adults without multivessel involvement, positive tests were only observed in 15 patients and normal tests in 45. Thus, a sensitivity of 56%, specificity of 73%, positive predictive value of 50% and negative predictive value of 77% were found. When patients showed high risk exercise test criteria, the exercise test positive predictive value increased to 80%.

CONCLUSIONS

Due to the lower sensitivity of this test in young myocardial infarction survivors for detecting multivessel artery disease, we remark on the need for predischarge complementary tests such as isotopic, stress echocardiography or coronariography testing.

Application of thermal desorption to the biological monitoring of organic compounds in exhaled breath

We have developed a thermal desorption-gas chromatographic method for the analysis of organic compounds in exhaled breath air, to be used in the biological monitoring of environmental exposure. The exhaled breath sampler is based on the concentration of compounds present in alveolar air in a solid sorbent material. Isoflurane (1-chloro-2,2,2-trifluoroethyl-difluoromethyl-ether), an inhaled anaesthetic used widely in surgery, and styrene, used in boat construction and the manufacture of fibreglass-reinforced plastics, are partially eliminated from the body in exhaled breath, samples of which can therefore be used to monitor biological exposure to these two organic compounds. Recoveries were tested in controlled atmospheres of isoflurane or styrene, with Chromosorb 106 or Tenax, respectively, as the adsorbent. We also investigated the influence of relative humidity, an important factor in breath sampling, on adsorption.