Can hyperbaric oxygen be used as adjunctive heart failure therapy through the induction of endogenous heat shock proteins

Heart failure (HF) is a chronic condition that is expected to increase in incidence along with increased life expectancy and an aging population. As the incidence of HF increases, the cost to national healthcare budgets is expected to run into the billions. The costs of lost productivity and increased social reliance on state support must also be considered. Recently, acute myocardial infarction (AMI) has come to be seen as the major contributing factor to HF. Although thrombolysis may restore coronary perfusion after an AMI, it may also introduce ischemic reperfusion injury (IRI). In an attempt to ameliorate sustained protein damage caused by IRI, endogenous chaperone proteins known as heat shock proteins (HSPs) are induced as a consequence of the stress of IRI. Recently, hyperbaric oxygen has been shown to induce the production of HSPs in noncardiac tissue, with a resultant protective effect. This current opinion review article suggests a possible role for hyperbaric oxygen, as a technologically modern drug, in augmenting the induction of endogenous HSPs to repair and improve the function of failing hearts that have been damaged by AMI and IRI. In addition, this simple, safe, noninvasive drug may prove useful in easing the economic burden of HF on already overextended health resources.     

Conversion of recent-onset atrial fibrillation or flutter with ibutilide after amiodarone has failed

OBJECTIVE: To evaluate whether ibutilide can convert atrial fibrillation or flutter in patients in whom amiodarone has failed. DESIGN AND SETTING: Clinical study in a university hospital intensive care unit (ICU). PATIENTS: Twenty-six patients were studied, in whom atrial fibrillation or flutter persisted for a maximum of 6 h at maximum. Patients were monitored continuously during the arrhythmia. Medical conversion was necessary due to symptomatic or hemodynamic causes. INTERVENTIONS: All patients initially received amiodarone (150 mg i.v.) and after 2 h of persistent arrhythmia ibutilide (1 mg or, without success and body weight > 70 kg, 2 mg i.v.). Before the administration of ibutilide 1 g magnesium was administered, and high normal levels of potassium serum levels were achieved (4.5-5.0 mmol/l). RESULTS. After amiodarone atrial flutter persisted in 73% and atrial fibrillation in 27% of patients. After ibutilide the QT interval was prolonged from 327 +/- 61 to 387 +/- 62 ms. The QTc interval increased from 456 +/-32 to 461 +/- 66 ms. Conversion to normal sinus rhythm was achieved in 22 of 27 of cases. Nonsustained torsade de pointes tachycardia was seen in three patients (11%). No patient showed sustained ventricular tachycardia. Patients with proarrhythmic effects were characterized by a decreased left ventricular function. CONCLUSIONS: In ICU patients ibutilide led to conversion to sinus rhythm in 81.5% of patients in whom amiodarone was unsuccessful. Nonsustained tachycardias were seen in 11%; sustained ventricular tachycardia was not seen. Ibutilide seems to be well suitable for conversion of recent onset atrial fibrillation or flutter and had no severe side effects in this study population.     

Why do GPs with a special interest in headache investigate headache presentations with neuroradiology and what do they find?

The general practitioner with a special interest in headache offers an important contribution to the management of headache in primary care where the majority of presentations take place. A number of guidelines have been developed for neuroradiological investigation of headache, but their clinical utility and relevance is not known. Fourteen general practitioners with a special interest in headache recorded consecutive headache consultations over a 3-month period, whether patients were investigated with neuroradiology and if so the reason for investigation and outcome. Reason for investigation was compared to the guidelines published for the use in primary care. 895 patients were seen, of whom 270 (30.1%) were investigated. 47% of indications were outside the guidance framework used, the most common reason for investigation being reassurance. Of those investigated, 5.6% showed positive findings but only 1.9% of findings were felt to be of clinical significance. General practitioners with a special interest investigated with neuroradiology a greater level than general practitioners, but less than neurologists. However, yields of significant findings are broadly comparative across all groups. This report confirms other studies that suggest that even when there is a high level of clinical suspicion, yields of significant findings are very low.     

Clinical application of a new method that segments the region of interest into multiple layers for RF amplitude histogram analysis in the cirrhotic liver

Purpose We used texture analysis in conjunction with an alternative method of analyzing the amplitude histogram using a radiofrequency (RF) signal to differentiate ultrasonograms of normal and cirrhotic livers. This method segments the region of interest (ROI) into multiple layers (sub-ROIs). In each sub-ROI of a homogeneous medium, the histogram of enveloped-amplitude of RF backscattered echoes resembles a Rayleigh distribution. Theoretically, the values of the signal-to-noise ratio (SNR), skewness, and kurtosis for Rayleigh statistics are constant and independent of the mean scattering intensity, which is contributed by such undesirable effects as tissue attenuation, beam diffraction, and incident waveforms. These values, which averaged overall sub-ROI, should provide an unbiased estimator.Methods We studied 36 normal livers and 28 cirrhotic livers, all confirmed by clinical findings including laboratory and pathology data; the SNR, skewness, and kurtosis values of the disease groups were compared. At the same time, these values were estimated using the conventional method, which did not segment the ROI into multiple sub-ROIs. The unpaired t-test was used to determine statistical significance.Results With the new method, all values obtained from cirrhotic livers differed significantly from those obtained from normal livers, and the standard deviation of these values was smaller than those obtained using the conventional method.Conclusions These results suggest that the new method can be used to diagnose the cirrhotic liver objectively.This article is translated from the Japanese version, which was published in J Med Ultrasonics 2001;28:J25–33     

Cerebral tissue oxygenation measured by two different probes: challenges and interpretation

Purpose  

Cerebral tissue oxygenation (PbrO₂) is most frequently monitored using a Licox CC1.SB system (LX, Integra Neuroscience, France) but recently a new probe—the Neurovent-PTO (NV)—was introduced by a different manufacturer (Raumedic, Germany). There are no prospective data on how these probes compare in clinical routine. We therefore compared both probes in comatose patients suffering from traumatic brain injury (TBI) or subarachnoid haemorrhage (SAH) during dynamic changes of inspirational oxygen fraction (FiO₂) and mean arterial pressure (MAP).     

Adrenal insufficiency in prolonged critical illness

Introduction  

Adrenal insufficiency is common in critically ill patients and affects their prognosis, but little is known about how adrenal function changes during prolonged critical illness. This study was conducted to investigate dynamic changes in cortisol levels in patients with critical illness who do not improve after treatment.     

The association of endothelial cell signaling,severity of illness,and organ dysfunction in sepsis

Introduction  

Previous reports suggest that endothelial activation is an important process in sepsis pathogenesis. We investigated the association between biomarkers of endothelial cell activation and sepsis severity, organ dysfunction sequential organ failure assessment (SOFA) score, and death.