			Home About us Contact

Respiratory Compensation (respiratory + compensation)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Topiramate-induced metabolic acidosis: report of two cases

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 10 2001
Chun-hung Ko MRCP FHKAM Medical Officer
Two children who presented with symptomatic metabolic acidosis after being put on topiramate (TPM) are reported. The first patient was an 11-year-old male with refractory complex partial epilepsy who was put on TPM for 13 months. He developed hyperventilation 1 week after increasing the dose to 300mg/day. Arterial blood gas revealed hyperchloraemic metabolic acidosis with partial respiratory compensation: pH 7.36, PCO2 27.2 mmHg, bicarbonate 14.9 mEq/L, base excess -8.9 mmol/L. Hyperventilation and acidosis resolved after administration of sodium bicarbonate and reduction of the dose of TPM. The second patient was a female who developed increasing irritability at age 16 months and 21 months, each time associated with introduction of TPM and resolved promptly upon withdrawal of the drug. Venous blood gas taken during the second episode revealed pH 7.34, PCO2 37.4 mmHg, bicarbonate 20.4 mEq/L, base excess -4.2 mmol/L. The predominant mechanism of TPM-induced hyperventilation involves inhibition of carbonic anhydrase at the proximal renal tubule, resulting in impaired proximal bicarbonate reabsorption. The occurrence of hyperpnoea or mental status change in any patient who is on TPM should prompt an urgent blood gas sampling, with correction of the acid-base disturbances accordingly. [source]

Methanol outbreak in Norway 2002,2004: epidemiology, clinical features and prognostic signs

JOURNAL OF INTERNAL MEDICINE, Issue 2 2005
K. E. HOVDA
Abstract. Objectives., Knowledge on methanol poisoning does mainly come from clinical studies. We therefore report epidemiological, clinical and prognostic features from the large methanol outbreak in Norway in 2002,2004 where the new antidote fomepizole was the primary antidote in use. Design and subjects., Combined prospective and retrospective case series study of 51 hospitalized patients who were confirmed poisoned with methanol, of whom nine died. In addition, eight patients died outside hospital. Most patients were admitted in a late stage and because of symptoms. Treatment consisted of alkali, fomepizole (71%) and haemodialysis (73%). Results., The median serum methanol was 25.0 mmol L,1 (80 mg dL,1) (range 3.1,147.0 mmol L,1), median pH was 7.20 (6.50,7.50), and median base deficit 22 mmol L,1 (range 0,31). The most frequent clinical features reported were visual disturbances (55%), dyspnoea (41%), and gastrointestinal symptoms (43%). Twenty-four per cent were comatose on admission, of whom 67% died. There was a trend towards decreasing pCO2 with decreasing pH amongst the patients surviving. The opposite trend was demonstrated in the dying; the difference was highly significant by linear regression analyses (P < 0.001). Conclusions., Methanol poisoning still has a high morbidity and mortality, mainly because of late diagnosis and treatment. Respiratory arrest, coma and severe metabolic acidosis (pH < 6.90, base deficit >28 mmol L,1) upon admission were strong predictors of poor outcome. Early admission and ability of respiratory compensation of metabolic acidosis was associated with survival. [source]

Real-time Fourier velocity encoding: An in vivo evaluation

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2005
Christopher K. Macgowan PhD
Abstract Purpose To compare in vivo real-time Fourier velocity encoding (FVE), spectral-Doppler ultrasound, and phase-contrast (PC) magnetic-resonance (MR) imaging. Materials and Methods In vivo velocity spectra were measured in the suprarenal and infrarenal aorta and the hepatic segment of the inferior vena cava of eight normal volunteers using FVE, and compared to similar measurements using Doppler ultrasound and gated PC MR imaging. In vivo waveforms were compared qualitatively according to flow pattern appearance (number, shape, and position of velocity peaks) and quantitatively according to peak velocity. Results Good agreement was obtained between peak velocities measured in vitro using FVE and PC MR imaging (R2 = 0.99, P = 2.10,6, slope = 0.97 ± 0.05). Qualitatively, the FVE and ultrasound measurements agreed closely in the majority of in vivo cases (excellent or good in 21/24 cases) while the PC MR method resolved fewer velocity peaks due to the inherent temporal averaging of cardiac-gated studies (excellent or good agreement with FVE in 13/24 cases). Quantitatively, the FVE measurement of peak velocity correlated strongly with both ultrasound (R2 = 0.71, P = 2.10,7, slope = 0.81 ± 0.08) and PC MR (R2 = 0.85, P = 2.10,10, slope = 1.04 ± 0.08). Conclusion Real-time MR assessment of blood-flow velocity correlated well with spectral Doppler ultrasound. Such new methods may allow hemodynamic information to be acquired in vessels inaccessible to ultrasound or in patients for whom respiratory compensation is not possible. J. Magn. Reson. Imaging 2005;21:297,304. © 2005 Wiley-Liss, Inc. [source]

Exercise test mode dependency for ventilatory efficiency in women but not men

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 2 2006
James A. Davis
Summary Ventilatory efficiency is commonly defined as the level of ventilation V,E at a given carbon dioxide output (V,CO2). The slope of the V,E versus V,CO2 relationship and the lowest V,E/V,CO2 are two ventilatory efficiency indices that can be measured during cardiopulmonary exercise testing (CPET). A possible CPET mode dependency for these indices was evaluated in healthy men and women. Also evaluated was the relationship between these two indices as, in theory, V,E/V,CO2 falls hyperbolically towards an asymptote that numerically equals the V,E versus V,CO2 slope at exercise levels below the ones that cause respiratory compensation for metabolic acidosis. Twenty-eight healthy subjects (14 men) underwent treadmill and cycle ergometer CPET on different days. Ventilation and the gas fractions for oxygen and CO2 were measured with a vacumed metabolic cart. In men, paired t -test analysis failed to find a mode difference for either ventilatory efficiency index but the opposite was true in the women as each woman had higher values for both indices on the treadmill. For men, the lowest V,E/V,CO2 was larger than the V,E versus V,CO2 slope by 1·3 on the treadmill and 0·8 on the cycle ergometer. The corresponding values for women were 1·7 and 1·4. We conclude that in healthy subjects, women, but not men, demonstrate a mode dependency for the two ventilatory efficiency indices investigated in this study. Furthermore, our results are consistent with the theoretical expectation that the lowest V,E/V,CO2 has a numerical value just above the asymptote of the V,E/V,CO2 versus V,CO2 relationship. [source]