Isabelle Alves

University of Lille Nord de France, Lille, Nord-Pas-de-Calais, France

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Publications (5)15.66 Total impact

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    ABSTRACT: We tested the effects of activated protein C (APC) in macro and microvascular beds within 60 minutes of treatment. Twelve patients treated with APC for severe sepsis were included. We assessed macrovascular reactivity by phenylephrine arterial dose-response. Pharmacological modeling (EC50, Emax and Hill coefficient) and individual dose-response curve were tested. Microvascular reactivity was tested with skin laser-Doppler by using post-occlusive reactive hyperemia (PORH) with measurements of peak, time to peak (Tmax), time to half recovery (T1/2R) and myogenic and sympathetic tones. All measurements were done 30 minutes before, just before and 30 minutes and 60 minutes after APC infusion. Microvascular reactivity was also tested in 8 healthy volunteers. In patients, arterial pressure did not increase significantly. However, 60 minutes after the beginning of APC infusion, reactivity to alpha-1 stimulation was improved: EC50 decreased from 15.3 (0.9-55830) to 3.1 (1.0- 6.2) (p=0.04) and 5/12 patients improved their dose-response curve. As for microcirculatory parameters, as early as 30 minutes after the beginning of APC infusion, PORH peak increased from 102 (40-168) to 162 (35-196) (p=0.04), Tmax was shorter: 30 (14-52) vs 56 (22-83) sec (p=0.03) and the T1/2R also decreased, from 72.4 sec (41.9-134.6) to 49.8 sec (31.0-129.8) (p=0.02). Myogenic tone increased (p=0.03) whereas sympathetic tone decreased (p=0.03) and myogenic tone was lower than controls before but not after APC treatment. In conclusion, APC improves vascular reactivity both at macro- and microcirculatory levels very quickly, suggesting that this is not due to protein synthesis or anticoagulant effect. The myogenic properties of vessels could partly drive this effect.
    Shock (Augusta, Ga.) 09/2013; 40(6). DOI:10.1097/SHK.0000000000000060 · 2.73 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the manual compression of the abdomen (MCA) during expiration as a simple bedside method to detect expiratory flow limitation (EFL) during daily clinical practice of mechanical ventilation (MV). We studied 44 semirecumbent intubated and sedated critically ill patients. Flow-volume loops obtained during MCA were superimposed upon the preceding breaths and recorded with the ventilator. Expiratory flow limitation was expressed as percentage of expiratory tidal volume without any increase in flow during MCA (MCA [%V(T)]). In the first 13 patients, MCA was validated by comparison with the negative expiratory pressure (NEP) technique. Esophageal pressure changes during MCA and intrinsic positive end-expiratory pressure were also recorded in all the patients. Manual compression of the abdomen and NEP agreed in all cases in detecting EFL with a bias of -0.16%. Percentage of expiratory tidal volume without any increase in flow during MCA is highly correlated with percentage of expiratory tidal volume without any increase in flow during NEP (n = 13, P < .0001, r(2) = 0.99) and intrinsic positive end-expiratory pressure (n = 44, P < .001, r(2) = 0.78), with a good repeatability (n = 44; within-subject SD, 5.7%) and reproducibility (n = 13; within-subject SD, 2.41%). Two third of the patients were flow limited, among whom one third had no previously known respiratory disease. Manual compression of the abdomen provides a simple, rapid, and safe bedside reliable maneuver to detect and quantify EFL during mechanical ventilation.
    Journal of critical care 07/2011; 27(1):37-44. DOI:10.1016/j.jcrc.2011.05.011 · 2.19 Impact Factor
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    ABSTRACT: To determine the impact of polyurethane (PU) on variations in cuff pressure (P (cuff)) in intubated critically ill patients. Prospective observational before-after study performed in a ten-bed ICU. Cuff pressure was continuously recorded for 24 h in 76 intubated patients, including 26 with polyvinyl chloride (PVC), 22 with cylindrical polyurethane (CPU), and 28 with tapered polyurethane (TPU)-cuffed tracheal tubes. P (cuff) was manually adjusted every 8 h by nurses and was maintained around 25 cmH(2)O. Time spent with cuff underinflation and overinflation was continuously measured. In addition, pepsin, a proxy for microaspiration of gastric contents, was quantitatively measured in tracheal secretions at the end of recording period. A total of 1,824 h of continuous recording of cuff pressure was analyzed. Patient characteristics were similar in the three groups. No significant difference was found in percentage of time spent with underinflation (mean +/- SD, 26 +/- 22, 28 +/- 12, 30 +/- 13% in PVC, CPU, and TPU groups, respectively) and overinflation [median (IQR), 7 (2-14), 6 (3-14), 11% (5-20)] among the three groups. However, a significant difference was found in the coefficient of variation of P (cuff) (mean +/- SD, 82 +/- 48, 92 +/- 47, 135 +/- 67, p = 0.002). While the coefficient of P (cuff) variation was significantly (p < 0.017) higher in the TPU compared to CPU and PVC groups, no significant difference was found between the CPU and PVC groups. The pepsin level was significantly different among the three groups (408 +/- 282, 217 +/- 159, 178 +/- 126 ng/ml; p < 0.001). In fact, the pepsin level was significantly lower in the CPU and TPU groups compared with the PVC group. PU does not impact variations in P (cuff) in critically ill patients.
    European Journal of Intensive Care Medicine 07/2010; 36(7):1156-63. DOI:10.1007/s00134-010-1892-7 · 5.54 Impact Factor
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    ABSTRACT: The aim of this prospective observational study was to determine the accuracy of American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) criteria in predicting infection or colonization related to multidrug-resistant (MDR) bacteria at intensive-care unit (ICU) admission. MDR bacteria were defined as methicillin-resistant Staphylococcus aureus, ceftazidime-resistant or imipenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, and extended-spectrum β-lactamase-producing Gram-negative bacilli. Screening for MDR bacteria (using nasal and rectal swabs and tracheal aspirates from intubated patients) was performed at ICU admission. Risk factors for infection or colonization with MDR bacteria at ICU admission were determined using univariate and multivariate analyses. The accuracy of ATS/IDSA criteria in predicting infection or colonization with these bacteria at ICU admission was calculated. Eighty-three (13%) of 625 patients were infected or colonized with MDR bacteria at ICU admission. Multivariate analysis allowed identification of prior antimicrobial treatment (OR 2.3, 95% CI 1.2-4.3; p 0.008), residence in a nursing home (OR 2, 95% CI 1.1-3.7; p <0.001), and prior hospitalization (OR 3.9, 95% CI 1.7-8.8; p <0.001) as independent predictors of infection or colonization with MDR bacteria at ICU admission. Although sensitivity (89%) and negative predictive values (96%) were high, low specificity (39%) and a positive predictive value (18%) were found when ATS/IDSA criteria were used in predicting infection or colonization with MDR bacteria at ICU admission. In patients with pneumonia, adherence to guidelines was associated with increased rates of appropriate initial antibiotic treatment and de-escalation. ATS/IDSA criteria had an excellent negative predictive value and a low positive predictive value concerning infection or colonization with MDR bacteria at ICU admission.
    Clinical Microbiology and Infection 08/2009; 16(7):902-8. DOI:10.1111/j.1469-0691.2009.03027.x · 5.20 Impact Factor
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    ABSTRACT: Acute delirium is a commonly encountered problem in the intensive care unit (ICU), which has a myriad of causes and contributes to poor outcomes. We present the case of an alcoholic critically ill patient who developed prolonged acute ICU delirium wrongly diagnosed as sedation and alcohol withdrawal. Protracted vomiting, swallowing disorders and continuous aspirations prevented him from enteral feeding and discontinuation of mechanical ventilation. After several days, it became clear that the patient had been misdiagnosed. Fortunately, nystagmus and ophthalmoplegia then allowed the recognition of Wernicke's encephalopathy, confirmed by cerebral MRIs. After thiamine supplementation, his state improved but he was discharged only on day 32. Wernicke's encephalopathy is an acute reversible neuropsychiatric emergency, which is falsely considered as uncommon, and is largely misdiagnosed, especially in critically ill patients. Thiamine should be systematically given to all critically ill alcoholic patients, especially those with protracted vomiting.
    Case Reports 04/2009; 2009. DOI:10.1136/bcr.10.2008.1096