Effect of hyperventilation on electroencephalographic activity.

OBJECTIVE: To observe the effect of voluntary hyperventilation on electroencephalographic activity during routine EEG recording on patients referred to a tertiary care hospital. METHODS: This was an observational study conducted at Neurophysiology Lab, Department of Neurology at Liaquat National Hospital, Karachi from May 2007 to September 2007. Data of 326 patients was collected prospectively and analyzed by SPSS version 10.0. At least 3 minutes voluntary hyperventilation was performed by the subjects. All those patients who were able to perform voluntary hyperventilation adequately were included in the study. RESULTS: Of 326 recordings, 256 (78.8%) were normal and 69 (21.2%) were abnormal. Focal epileptiform discharges were identified in 8.6% and generalized in 8.3% of subjects. Physiological slowing was found in 31 records. Out of 55 epileptics, 3 had discharges only during HV and 9 had increase in epileptiform discharges. CONCLUSION: Hyperventilation has significant effect on background rhythm during EEG recording. It is a useful activation method utilized to increase the yield of EEG.

Factors delaying hospital arrival of patients with acute stroke.

INTRODUCTION: To determine the proportion of patients with acute stroke presenting late to hospital and to identify the factors that delay hospital arrival of patients with acute stroke. METHODS: A cross sectional study was carried out between Sept 2006 to Feb 2007 in the department of Neurology, Liaquat National Hospital Karachi. All patients of both genders, ago >18 years with symptoms of stroke and neuro- imaging (CT scan/MRI brain) findings consistent with stroke were included. RESULTS: Atotal of 165 patients attending the Emergency department were included. There were 86 (52%) males and 79 (47.9%) females. The mean age was 60.04+/-13.98 years, (males 58.2 years and females 61.9 years). The median delay from onset of symptoms to hospital arrival was six hours. Only 28.5% of the patients came within three hours while 71.5% after three hours. Attendants of 47 patients had a low throat perception, 53 (32%) of the patients did not know a single symptom of stroke and 63% (104) patients first contacted their General Practitioner who referred them to hospital. Similarly 60.6% of patients wore first taken to a local hospital not equipped to handle major emergencies. CONCLUSION: Time elapsed from onset of symptoms to hospital arrival is influenced by lack of knowledge of stroke symptoms, contact with a local doctor, low threat perception and non availability of ambulance services.