Value of the venous-arterial PCO2 gradient to reflect the oxygen supply to demand in humans: effects of dobutamine.

OBJECTIVE: To test the value of venous-arterial PCO2 gradient (deltaPCO2) measurements to reflect the adequacy of cardiac index (CI) to oxygen demand in patients submitted to rapid changes of CI and oxygen demand. DESIGN: Prospective, comparative study. SETTING: Medical intensive care unit of a university hospital. PATIENTS: Ten patients with congestive heart failure exhibiting low baseline CI (< or =2.5 L/min/m2) but no evidence of global tissue hypoxia, as attested by the absence of clinical signs of shock and by normal blood lactate concentrations. INTERVENTIONS: Infusion of incremental doses of dobutamine: 0 (D0), 5 (D5), 10 (D10), and 15 (D15) microg/kg/min. MEASUREMENTS AND MAIN RESULTS: The CI increased by a linear fashion from D0 (1.6+/-0.1 L/min/m2) to D15 (2.4+/-0.2 L/min/m2) (p< .05). The mixed venous oxygen saturation (SVO2) increased from D0 (49+/-2%) to D10 (61+/-2%) (p < .05) and remained unchanged from D10 to D15 (60+/-2%). The oxygen extraction ratio (O2 ER) and the deltaPCO2 decreased from D0 (48+/-2% and 9+/-1 torr [1.2+/-0.3 kPa], respectively) to D10 (36+/-2% and 5+/-1 torr [0.7+/-0.1 kPa], respectively) (p < .05 for both comparisons) and remained unchanged from D10 to D15 (36+/-2% and 6+/-1 torr [0.8+/-0.1 kPa], respectively). The biphasic courses of SVO2, O2 ER, and deltaPCO2 were related to the course of oxygen consumption that remained constant from D0 (113+/-9 mL/min/m2) to D10 (112+/-8 mL/min/m2) and significantly increased from D10 to D15 (127+/-10 mL/min/m2) (p <.05). CONCLUSIONS: deltaPCO2 can be reliably used at the bedside for informing on the adequacy of CI with respect to a given metabolic condition, and particularly for detecting changes in oxygen demand (e.g., the changes accompanying drug-induced changes in CI). In this regard, deltaPCO2, together with O2 ER and SVO2, can help to assess the adequacy of CI to global oxygen demand.

Ventilatory and hemodynamic effects of continuous positive airway pressure in left heart failure.

The ventilatory and hemodynamic effects of continuous positive airway pressure (CPAP) delivered via a face mask (at 0, 5, and 10 cm H2O, and after a return to 0 cm H2O) were studied in nine patients with acute left heart failure (pulmonary artery occlusion pressure [PAOP] > or = 18 mm Hg, and cardiac index [CI] < or = 2.8 L/min/m2). CPAP at 10 cm H2O induced an improvement in lung compliance (60 +/- 10 ml/cm H2O to 87 +/- 20 ml/cm H2O, p < 0.05) and in lung and airway resistance (5.7 +/- 1.0 cm H2O/L/s to 3.4 +/- 1.0 cm H2O/L/s, p < 0.05), a reduction in work of breathing (18 +/- 3 J/min to 12 +/- 2 J/min, p < 0.05), and in the pressure-time index of the respiratory muscles (279 +/- 22 cm H2O/s/min to 174 +/- 25 cm H2O/s/min, p < 0.05), without significant changes in breathing pattern. Despite a significant reduction in the negative swings in intrathoracic pressure (15.2 +/- 1.9 cm H2O to 10.8 +/- 1.8 cm H2O, p < 0.001), no significant change was observed in CI or stroke volume during CPAP. However, mean transmural filling pressures decreased significantly with CPAP, suggesting a better cardiac performance. Neither the level of stroke volume nor of PAOP, was predictive of changes in CI or in stroke volume. In patients with respiratory insufficiency caused by congestive heart failure (CHF), CPAP reduces respiratory muscle effort without altering cardiac output. The slight decrease in mean transmural left and right atrial pressures suggests an improvement in cardiac performance.

CT assessment of bronchi in sarcoidosis: endoscopic and pathologic correlations.

PURPOSE: To evaluate the computed tomographic (CT) appearance of bronchi in patients with sarcoidosis and to correlate CT, endoscopy, and bronchial biopsy findings. MATERIALS AND METHODS: Sixty patients with sarcoidosis underwent CT and tracheobronchial endoscopy. CT findings of abnormalities of the bronchial walls and lumina were compared with endoscopic and biopsy findings. RESULTS: CT scans showed bronchial abnormalities in 39 patients (65%). CT and endoscopic findings were concordant in only 35 cases. However, CT showed abnormal lumina in 14 patients and endoscopy showed mucosal thickening in 12 of these 14 patients. CT findings of bronchial abnormalities were associated with the presence of bronchial granulomas (P < .0001). CT scans showed that, of the 37 patients with biopsy results of granulomatosis, 84% had thickened bronchial walls and 35% had luminal abnormalities. Eight CT findings were false-positive, and six were false-negative for the presence of granulomas. CONCLUSION: Bronchial involvement in sarcoidosis was detected at CT in 65% of cases. CT can help predict whether bronchial granulomas will be found in cases of sarcoidosis.

Cardiorespiratory effects of pressure-controlled ventilation with and without inverse ratio in the adult respiratory distress syndrome.

To assess the cardiorespiratory effects of pressure-controlled ventilation (PCV) and pressure-controlled inverse ratio ventilation (PC-IRV), we compared pressure-controlled ventilation with an inspiratory-to-expiratory time ratio (I/E) of 1/2 (PCV) and of 2/1 (PC-IRV) to volume-controlled ventilation (VCV) with an I/E of 1/2 in 10 patients suffering from the adult respiratory distress syndrome. In all modes, the inspiratory oxygen fraction, tidal volume, respiratory rate, and total positive end-expiratory pressure (PEEPt = applied PEEP + intrinsic PEEP) were kept constant. Each ventilatory mode was applied for 1 h in a randomized order. No significant differences in PaO2 were observed among the three modes. The PaCO2 was lower (p < 0.05) in PC-IRV (39 +/- 4 mm Hg) than in PCV (43 +/- 5 mm Hg) and in VCV (45 +/- 5 mm Hg). The peak airway pressure was significantly lower in PC-IRV than in PCV (p < 0.05) and in PCV than in VCV (p < 0.05), but plateau pressure was not different in the 3 modes. The mean airway pressure (mPaw) was significantly higher (p < 0.05) in PC-IRV (21.4 +/- 0.7 cm H2O) than in PCV (17.1 +/- 0.7 cm H2O) and VCV (16.4 +/- 0.5 cm H2O). As a consequence of this increased mPaw, PC-IRV induced a decrease in cardiac index (CI) (3.3 +/- 0.2 vs 3.7 +/- 0.2 L/min/m2 in VCV; p < 0.05) and hence in oxygen delivery (DO2) (424 +/- 28 vs 469 +/- 38 ml/min/m2 in VCV; p < 0.05). Our results suggest that neither PCV nor PC-IRV bring any benefit over VCV in terms of arterial oxygenation. Moreover, the increase in mPaw induced by PC-IRV may be deleterious to the CI and DO2.

Acute monocytic leukemia: prevalent cutaneous lesions. Two cases.

The authors report two cases of acute myeloid leukemia with prevalent cutaneous lesions. The positivity of granulo-monocytic antibodies and the exclusive cutaneous site of the lesions drove them previously to the diagnosis of histiocytic sarcoma. These cases stress the problem of the immunological identification of cutaneous lymphomas of "histiocytic" type.

[Respiratory complications of massive obesity]. / Les complications respiratoires des obésités massives.

Massive obesity may lead to serious, and sometimes fatal, respiratory complications. Alterations of ventilatory mechanics and function are well known; they include a decrease in respiratory compliance, an increase in ventilatory work and a restrictive pulmonary disease. Hypoxemia is rather due to an impaired ventilation/perfusion ratio than to alveolar hypoventilation. Sleep Apnea Syndrome (SAS) is very frequent in excessively obese patients. These subjects with daytime hypersomnolence should be systematically screened for SAS before the occurrence of life-threatening complications. Continuous positive airway pressure ventilation through a nasal mask is the treatment of choice of SAS especially since the results of body weight reduction and ENT surgery are inconstant and variable in these patients.

Adult-onset Still's disease revealed by a pleuropericarditis.

We report a case of adult-onset Still's disease (AOSD) revealed by pleuropericardial manifestations. A 40 yr old black woman was admitted for flu-like syndrome with pharyngitis, hectic fever, polymorphonuclear hyperleucocytosis and pleuropericarditis. The diagnosis of AOSD was supported by 3 major and 3 minor criteria after exclusion of infectious, haematological and connective tissue diseases. Pulmonary involvement is infrequent in AOSD, and consists of transient pulmonary infiltrates and chronic restrictive pattern. However, pleuritis, like pericarditis, is present in 25% of cases. Initial onset of pleuritis, associated with fever and hyperleucocytosis preceding articular manifestations could be responsible for a delay in diagnosis and a subsequent worsening in the prognosis of the disease. A rapid improvement is usually observed under nonsteroidal anti-inflammatory drug or corticosteroid treatment.