Oximetry Alone Versus Portable Polygraphy for Sleep Apnea Screening Before Bariatric Surgery

Background: Screening for obstructive sleep apnea (OSA) is recommended as part of the preoperative assessment of obese patients scheduled for bariatric surgery. The objective of this study was to compare the sensitivity of oximetry alone versus portable polygraphy in the preoperative screening for OSA. Methods: Polygraphy (type III portable monitor) and oximetry data recorded as part of the preoperative assessment before bariatric surgery from 68 consecutive patients were reviewed. We compared the sensitivity of 3% or 4% desaturation index (oximetry alone) with the apnea-hypopnea index (AHI; polygraphy) to diagnose OSA and classify the patients as normal (30 events per hour). Results: Using AHI, the prevalence of OSA (AHI > 10 per hour) was 57.4%: 16.2% of the patients were classified as severe, 41.2% as mild to moderate, and 42.6% as normal. Using 3% desaturation index, 22.1% were classified as severe, 47.1% as mild to moderate, and 30.9% as normal. With 4% desaturation index, 17.6% were classified as severe, 32.4% as mild, and 50% as normal. Overall, 3% desaturation index compared to AHI yielded a 95% negative predictive value to rule out OSA (AHI > 10 per hour) and a 100% sensitivity (0.73 positive predictive value) to detect severe OSA (AHI > 30 per hour). Conclusions: Using oximetry with 3% desaturation index as a screening tool for OSA could allow us to rule out significant OSA in almost a third of the patients and to detect patients with severe OSA. This cheap and widely available technique could accelerate preoperative work-up of these patient

Right-to-left shunt with hypoxemia in pulmonary hypertension

<p>Abstract</p> <p>Background</p> <p>Hypoxemia is common in pulmonary hypertension (PH) and may be partly related to ventilation/perfusion mismatch, low diffusion capacity, low cardiac output, and/or right-to-left (RL) shunting.</p> <p>Methods</p> <p>To determine whether true RL shunting causing hypoxemia is caused by intracardiac shunting, as classically considered, a retrospective single center study was conducted in consecutive patients with precapillary PH, with hypoxemia at rest (PaO₂< 10 kPa), shunt fraction (Qs/Qt) greater than 5%, elevated alveolar-arterial difference of PO₂(AaPO₂), and with transthoracic contrast echocardiography performed within 3 months.</p> <p>Results</p> <p>Among 263 patients with precapillary PH, 34 patients were included: pulmonary arterial hypertension, 21%; PH associated with lung disease, 47% (chronic obstructive pulmonary disease, 23%; interstitial lung disease, 9%; other, 15%); chronic thromboembolic PH, 26%; miscellaneous causes, 6%. Mean pulmonary artery pressure, cardiac index, and pulmonary vascular resistance were 45.8 ± 10.8 mmHg, 2.2 ± 0.6 L/min/m², and 469 ± 275 dyn.s.cm^-5, respectively. PaO₂in room air was 6.8 ± 1.3 kPa. Qs/Qt was 10.2 ± 4.2%. AaPO₂under 100% oxygen was 32.5 ± 12.4 kPa. Positive contrast was present at transthoracic contrast echocardiography in 6/34 (18%) of patients, including only 4/34 (12%) with intracardiac RL shunting. Qs/Qt did not correlate with hemodynamic parameters. Patients' characteristics did not differ according to the result of contrast echocardiography.</p> <p>Conclusion</p> <p>When present in patients with precapillary PH, RL shunting is usually not related to reopening of patent <it>foramen ovale</it>, whatever the etiology of PH.</p

Phénotype des myofibroblastes alvéolaires dans les différents types de fibrose pulmonaire

Le présent travail étudie l'expression d'α-actine muscle lisse (α-SM₁) dans les myofibroblastes (MyF) alvéolaires au cours de différentes pneumopathies interstitielles. Les maladies choisies sont la fibrose interstitielle idiopathique (IPF), y compris la pneumonie interstitielle courante (UIP), la fibrose interstitielle après administration de bléomycine, la BOOP, la silicose, la sarcoïdose et l'ARDS. Quarante-six cas ont été examinés en utilisant notamment des anticorps contre αSM₁, TGF-β₁ et ses récepteurs. Notre étude confirme que l'expression d'α-SM₁ par les MyF alvéolaires est caractéristique mais pas spécifique de l'IPF. On retrouve une telle modulation dans la fibrose interstitielle à la bléomycine, dans la phase chronique de l'ARDS et, selon d'autres publications, dans la transplantation pulmonaire (Mod Pathol 1997; 10; 1134-1142) et dans l'hypertension pulmonaire post-capillaire (Am J Pathol 1990; 136; 881-889). De plus, les corps de Masson en cas de BOOP, la périphérie des nodules silicotiques ainsi que celle des granulomes de la sarcoïdose, renferment de nombreux MyF α-SM₁ positifs; en revanche, les septums alvéolaires en sont dépourvus. La modulation des MyF alvéolaires α-SM₁ positifs est induite par le TGF-β₁. Cette modulation semble jouer un rôle important dans la production de fibres collagènes au niveau alvéolaire; elle contribue par ailleurs vraisemblablement à la réduction de la compliance pulmonaire

Right-to-left shunt in pulmonary hypertension

International audienc