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Biomedical subjects

Christophe Baillard

Publications and source records attributed to Christophe Baillard.

7 recordsLinked to original sources
PubMed2006

Noninvasive ventilation improves preoxygenation before intubation of hypoxic patients.

RATIONALE: Critically ill patients are predisposed to oxyhemoglobin desaturation during intubation. OBJECTIVES: To find out whether noninvasive ventilation (NIV), as a preoxygenation method, is more effective at reducing arterial oxyhemoglobin desaturation than usual preoxygenation during orotracheal intubation in hypoxemic, critically ill patients. METHODS: Prospective randomized study performed in two surgical/medical intensive care units (ICUs). Preoxygenation was performed, before a rapid sequence intubation, for a 3-min period using a nonrebreather bag-valve mask (control group) or pressure support ventilation delivered by an ICU ventilator through a face mask (NIV group) according to the randomization. MEASUREMENTS AND MAIN RESULTS: The control (n = 26) and NIV (n = 27) groups were similar in terms of age, disease severity, diagnosis at admission, and pulse oxymetry values (Sp(O(2))) before preoxygenation. At the end of preoxygenation, Sp(O(2)) was higher in the NIV group as compared with the control group (98 +/- 2 vs. 93 +/- 6%, p < 0.001). During the intubation procedure, the lower Sp(O(2)) values were observed in the control group (81 +/- 15 vs. 93 +/- 8%, p < 0.001). Twelve (46%) patients in the control group and two (7%) in the NIV group had an Sp(O(2)) below 80% (p < 0.01). Five minutes after intubation, Sp(O(2)) values were still better in the NIV group as compared with the control group (98 +/- 2 vs. 94 +/- 6%, p < 0.01). Regurgitations (n = 3; 6%) and new infiltrates on post-procedure chest X ray (n = 4; 8%) were observed with no significant difference between groups. CONCLUSION: For the intubation of hypoxemic patients, preoxygenation using NIV is more effective at reducing arterial oxyhemoglobin desaturation than the usual method.

Aged↗
PubMed2004

Assessing residual neuromuscular blockade using acceleromyography can be deceptive in postoperative awake patients.

UNLABELLED: Postoperative awake patients may have significant residual neuromuscular block. In awake patients, the results of accelerometry are affected by extra movements to which the thumb may be subject. In this study, we evaluated the repeatability of train-of-four (TOF) ratio using acceleromyography in 253 patients recovering from anesthesia. Immediately after arrival in the postanesthesia care unit, the ulnar nerve was stimulated with TOF stimulation. The evoked response at the thumb was measured by the TOF-Watch apparatus. The current intensity was 30 mA. Two TOF stimulations were applied and recorded at 30-s intervals. A Bland-Altman test was used. The Kappa (kappa) test for clinical agreement between the two measurements was also calculated according to the presence or absence of a residual neuromuscular blockade, defined as a TOF ratio <0.9. According to the presence of a residual neuromuscular blockade, the paired TOF ratios were discordant in 61 patients (24%; 95% confidence interval, 21%-27%). The kappa test indicated a moderate agreement (k = 0.47). We demonstrated that accelerometry as used in this study is not always accurate. Two isolated acceleromyograph TOF ratios are not an accurate representation of the neuromuscular status of the patient recovering from anesthesia. IMPLICATIONS: Clinicians should be aware that acceleromyography as used in this study does not always provide precise train-of-four ratio measurements. Two isolated acceleromyograph train-of-four ratios are not an accurate representation of the neuromuscular status of the patient recovering from anesthesia.

Adult↗
PubMed2003

The long QT interval is not only inherited but is also linked to cardiac hypertrophy.

This review focuses on the molecular determinants of the duration of the QT interval as measured on by electrocardiography in normal subjects and during cardiac hypertrophy and failure. (a) In control conditions, on a single cell, the shape and duration of the action potential is the result of a balance between different ion currents which in turn were determined by the number of functional channels. On multicellular preparations the QT duration also represents the repolarization time; nevertheless it is modified by the transmural gradients. On body-surface electrocardiography the duration of the QT interval depends also of an additional factor: the spatial three-dimensional projection of the electrical waves vectors, which makes any determination of the epicardial dispersion by measuring QT interval dispersion questionable. (b) The enhanced action potential duration is well documented in cardiac hypertrophy and heart failure and is usually caused by a reduction in outward current densities in most of the species except mice. Among these currents I(tO) is the most frequently altered, especially in humans. Such an altered current density is caused by a diminished expression of the genes encoding either the ion channel subunits or regulatory proteins, such as KChIP2. In addition, hypertrophy modifies or even reverses the transmural gradient. In human and rats hypertensive cardiopathy is associated with a prolongation of the QT interval duration. The reduction in I(tO) is likely to be adaptive; it participates in the slowing of the cardiac cycle and reflects the fetal genetic reprogramming. Recent data also suggest that a reduction in the transient outward K(+) current density triggers protein synthesis through an activation of the calcineurin pathways. Thus a prolongation of the QT interval is not only inherited or drug-induced; it is also an essential component of the adaptive process in chronic mechanical overload. It is fundamentally incorrect to measure QT dispersion on a surface electrocardiography, but the mean QT interval may provide information concerning the progression of the disease, just as, and with the same restrictions, in the case of the quantification of V(max).

Animals↗
PubMed2003

Cardiac troponin I in patients with severe exacerbation of chronic obstructive pulmonary disease.

OBJECTIVES: Co-morbid conditions including risk factors for cardiovascular diseases and left ventricular dysfunction are common in patients with chronic obstructive pulmonary disease (COPD). This study assessed the incidence of cardiac troponin I (cTnI) elevation, a specific marker for cardiac injury, and its prognostic significance during severe exacerbation of COPD. DESIGN: Prospective cohort study. SETTING: Two intensive care units. PARTICIPANTS: Seventy-one consecutive patients admitted for severe exacerbation of COPD. INTERVENTION: None. MEASUREMENTS AND RESULTS: Cardiac troponin I was assayed in blood samples obtained on admission and 24 h later (Stratus II immunoassay analyser, Dade International). Levels above 0.5 ng/ml were considered positive. The following data were recorded prospectively: clinical symptoms, co-morbidities, cause of the exacerbation, diagnostic procedures and treatment, general severity score (SAPS II) and in-hospital outcome. CTnI was positive in 18% of patients (95% confidence interval (CI(95)), 11-29%), with a median value at 1.00 ng/ml; CI(95 )(0.60-1.70). Eighteen patients died in the hospital (25%; CI(95), 17-37%). Only cTnI (adjusted odds ratio (ORa), 6.52; CI(95),1.23-34.47) and SAPS II 24 h after admission (ORa, 1.07; CI(95), 1.01-1.13) were independent predictors of in-hospital mortality. CONCLUSION: Elevated cTnI is a strong and independent predictor of in-hospital death in patients admitted for acutely exacerbated COPD.

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PubMed2002

Brain death assessment using instant spectral analysis of heart rate variability.

OBJECTIVE: Confirmation of brain death requires an urgent diagnosis to allow rapid vital organ removal for transplantation. Evaluation of forebrain functions is commonly performed through electroencephalogram. Nevertheless, there are, for the moment, no methods that allow for an instantaneous evaluation of brainstem functions. During acute brain injury, heart rate variability is an independent neurologic prognosis indicator resulting from a close relationship between brain stem and cardiac autonomic nervous system. This study aims to evaluate a new heart rate variability spectral analysis method, on a beat-to-beat basis, continuously over the time, during brain death. DESIGN: Prospective, nonrandomized, observational study. SETTING: Intensive care unit. SUBJECTS: Ten patients (age range 25-64 yrs, mean age 41 yrs) with acute brain injury leading to brain death. INTERVENTION: No intervention beyond standard of care MEASUREMENTS AND MAIN RESULTS: Heart rate, arterial blood pressure, heart rate variability in time and frequency domains method, which included calculation of the instant center frequency of spectrum. Brain death was associated with tachycardia (R-R interval 703 +/- 69 vs. 551 +/- 34 msec, p <.05), dramatic reduction of the global spectral power (44.919 +/- 31.511 vs. 3.204 +/- 1.469 msec(2), p <.05), and an abrupt shift of instant center frequency to a higher frequency range (0.17 +/- 0.01 vs. 0.26 +/- 0.03 Hz, p <.05). CONCLUSIONS: Such a method allows an instant, noninvasive determination of brainstem death based on a time and frequency domain analysis of heart rate variability.

Adult↗