A noninvasive tissue reflectance oximeter

A newly developed noninvasive tissue reflectance oximeter utilizes 5 light emitting diodes operating at the wavelengths of 0.635, 0.665, 0.795, 0.910, and 0.955 μ, and photodiodes to sample the tissue reflectance spectra. Since the tissue reflectance is affected by changes in both hemoglobin content (Hb _T) and hemoglobin oxygen saturation (OS _T),Hb _T is first determined using the reflectance at 0.795 μ. The hemoglobinOS _T is then estimated using the reflectances at the 5 wavelengths in conjunction with the diffuse reflectance equation which has previously been verified applicable to tissue reflectance oximetry. A quantitative estimation of bothHb _T andOS _T in intestinal mucosa of dogs obtained using this instrument showed thatHb _T values agreed fairly well with those of others and that the standard errors ofOS _T were around 5.0% inOS as compared with theOS values of blood samples for minimized arterial-venousOS differences. The continuous on-line measurement ofHb _T andOS _T should be possible using the reflectance technique and should be valuable for clinical evaluation of the patients.     

Sleepiness and nocturnal hypoxemia in Peruvian men with obstructive sleep apnea

Purpose

To evaluate the intensity of nocturnal hypoxemia associated with sleepiness in Peruvian men with a diagnosis of obstructive sleep apnea (OSA).

Methods

We carried out a secondary data analysis based on a study which includes patients with OSA who were seen in a private hospital in Lima, Peru from 2006 to 2012. We included male adults who had polysomnographic recordings and who answered the Epworth sleepiness scale (ESE). The intensity of nocturnal hypoxemia (oxygen saturation ≤90 %) was classified in four new categories: 0, <1, 1 to 10 and >10 % total sleep time with nocturnal hypoxemia (NH). When the ESE score was higher than 10, we used the definitions presence or absence of sleepiness. We used Poisson regression models with robust variance to estimate crude and adjusted prevalence ratios (PR) for association between sleepiness and NH.

Results

518 male patients with OSA were evaluated. Four hundred and fifty-two (87 %) patients had NH and 262 (51 %) had sleepiness. Of the 142 (27.4 %) patients who had >10 % total sleep time with NH, 98 (69.0 %) showed sleepiness and had a greater probability of sleepiness prevalence, with a crude PR of 1.82 (95 % CI 1.31–2.53). This association persisted in the multivariate models.

Conclusions

We found an association between NH and sleepiness. Only patients with the major intensity of NH (over 10 % of the total sleep time) had a greater probability of sleepiness. This suggests that sleepiness probably occurs after a chronic process and after overwhelming compensatory mechanisms.     

Survival of patients with chronic-phase chronic myeloid leukaemia on imatinib after failure on interferon alfa

Until the recent introduction of imatinib, interferon alfa was the standard treatment for patients in the chronic phase of chronic myeloid leukaemia. We compared survival of 143 such patients, who did not respond to interferon alfa and were treated with imatinib, with that of 246 historical controls who received conventional treatment. Patients on imatinib showed an overall survival advantage (relative risk 0.54, 95% CI 0.31-0.93). However, although patients on imatinib who achieved at least some degree of cytogenetic response after 6 months had better survival than controls (0.13, 0.05-0.39), those with no cytogenetic response to imatinib had significantly worse survival (1.69, 1.09-2.64). Our findings suggest that cytogenetic responders obtain benefit from imatinib but patients who show no cytogenetic response should be given alternative treatment without delay. We confirmed these results in a case-matched analysis.     

Pharmacological Stimulation of β <Subscript>2</Subscript>-adrenergic Receptors (β <Subscript>2</Subscript>AR) Enhances Therapeutic Effectiveness of β <Subscript>1</Subscript>AR Blockade in Rodent Dilated Ischemic Cardiomyopathy

Background. We have reported that β ₂ adrenoreceptor (β ₂AR) stimulation is anti-apoptotic, and has strong beneficial effect on cardiac remodeling in an experimental model of post myocardial infarction chronic heart failure (CHF) in rats. Here we investigate whether the addition of chronic pharmacological β ₂AR stimulation enhances the therapeutic effects of β ₁AR blockade on cardiac remodeling in the same model. Methods and Results. Metoprolol, a β ₁AR blocker, given alone (β ₁) or in combination with β ₂AR agonist, fenoterol (β ₁β ₂) were administered to rats via drinking water for 6 weeks, beginning 2 weeks following permanent coronary ligation. Progressive left ventricular (LV) remodeling of untreated animals, assessed by repeated echocardiography, occurred during the observation time, i.e., 42% and 25% increases in end-systolic and end-diastolic LV volumes respectively, 27% fall in ejection fraction, and 35% infarct expansion. Pressure-volume loop analyses at 2d and 8th post infarction weeks showed continuous deterioration of systolic and diastolic functions and arterio-ventricular mismatch. Histological evaluation at the end of 8 weeks revealed the MI expansion and hypertrophy of cardiomyocytes. β ₁β ₂ prevented LV remodeling, MI expansion and cardiomyocytes hypertrophy to a greater degree than β ₁, due, in large part, to a vasodilatory effect of β ₂AR stimulation and thus improvement of arterio-ventricular mismatch. The abnormal diastolic performance improved only in β ₁β ₂. β ₁β ₂ treatment reduced myocardial apoptosis throughout myocardium, but β ₁ reduced apoptopsis only in the areas remote from MI. Conclusion. The therapeutic effects of chronic β ₁AR blockade on cardiac remodeling of heart failure are enhanced and extended when supplemented with β ₂AR stimulation. This research was supported by the Intramural Research Program of the National Institute on Aging, NIH.     

Cardiac safety profile of nebulized formoterol in adults with COPD: a 12-week, multicenter, randomized, double- blind, double-dummy, placebo- and active-controlled trial

BACKGROUND: Recently, there have been concerns about the tolerability of long-acting (2)-agonists, including possible adverse cardiovascular effects-a particular concern in patients with chronic obstructive pulmonary disease (COPD), who are at elevated risk for cardiovascular disease. OBJECTIVE: The aim of this study was to assess the cardiac safety profile of nebulized formoterol fumarate inhalation solution. METHODS: Cardiac safety was assessed as part of a 12-week, randomized, double-blind, double-dummy, placebo- and active-controlled trial that was conducted at 38 centers across the United States. Male and female patients aged >/=40 years with COPD and without other significant disease were enrolled. After a 4- to 14-day, single-blind placebo run-in period, patients with COPD were randomly assigned to receive formoterol fumarate inhalation solution 20 microg BID via nebulizer (FFIS group), formoterol fumarate 12 microg BID via dry powder inhaler (FA group), or placebo. Cardiac effects-measured by changes in heart rate (HR) and ventricular premature beats; incidence of proarrhythmic events; change in corrected QT (QTc) interval; and incidence of maximum mean change in QTc >/=60 ms-were assessed using 24-hour Holter monitoring at baseline and 12 weeks; 12-lead electrocardiography at screening and weeks 4, 8, and 12; and patient diary cards. RESULTS: A total of 351 patients with COPD were randomized (mean age, 62.8 years; 56.1% male; mean postbronchodilator forced expiratory volume in 1 second, 1.5 L). Holter monitoring found no clinically meaningful effects of FFIS or FA treatment on mean or maximum HR, ventricular premature beats, or inci dence of arrhythmic events compared with placebo. At week 12, mean (SD) changes from baseline in mean HR were -0.6 (10.9), +0.1 (11.6), and -1.4 (9.4) bpm in the FFIS, FA, and placebo groups, respectively. The incidence of mean maximum changes in QTc >/=60 ms at any time during the 12-week treatment period were 1.6%, 1.8%, and 1.8% with FFIS, FA, and placebo, respectively. Treatment-emergent cardiac adverse events (AEs) occurred in 4.1%, 3.5%, and 4.4% of patients in the FFIS, FA, and placebo groups; withdrawals due to possible cardiac AEs occurred in 1 patient per treatment group. No deaths or serious cardiac AEs occurred during the treatment period. CONCLUSION: In this COPD population, no clinically significant cardiac effects were found with twicedaily treatment with nebulized formoterol fumarate inhalation solution.