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This abstract was not presented at the symposium.

This abstract was not presented at the symposium.

Introduction et but de l’etude Apres agression, l’acquisition d’une faiblesse musculaire est frequente et peut etre a l’origine de consequences fonctionnelles severes et durables, partiellement prevenues par la combinaison d’apports nutritionnels et d’activite physique adaptes. La securite de la mobilisation active n’est pas connue chez les patients dont les reserves physiologiques et la capacite a l’effort sont limitees. La mesure de la depense energetique (DE) peut constituer une information utile pour selectionner le mode de mobilisation le mieux adapte. L’objectif de cette etude est d’evaluer l’evolution de la DE des patients de soins intensifs au cours d’une mobilisation passive et d’une mobilisation active sur cycloergometre. Materiel et methodes Nous avons inclus les patients adultes hospitalises en soins intensifs pour plus de 24 heures ne presentant pas de contre-indication a la mobilisation. Le score de gravite SAPS III et le score fonctionnel musculaire MRC (faiblesse musculaire si Resultats et analyse statistique Douze patients (âge median 59 [53–73], 7 hommes, IMC median 24 [22–28], SAPS III median 64 [47–74], MRC median 49 [43–52]) ont participe a l’etude. Les variables cardiorespiratoires n’ont pas ete influencees par l’exercice. La dyspnee etait plus marquee apres mobilisation active que passive (EVN 5,0 [5,0–6,0] versus 3,5 [2,5–5,0], p Conclusion La mobilisation sur cycloergometre, qu’elle soit realisee activement ou passivement, n’est pas associee a un accroissement significatif de la DE chez le patient de soins intensifs agresse et stabilise sur le plan cardiovasculaire. Le rapport risque/benefice est donc clairement en faveur de l’utilisation du cycloergometre apres la phase initiale d’instabilite chez le patient agresse.

Laryngeal edema secondary to endotracheal intubation may require early re-intubation. Prior to extubation the absence of leak around an endotracheal tube may predict laryngeal edema after extubation. We evaluated the usefulness of a quantitative assessment of such a leak to identify the patients who will require early re-intubation for laryngeal edema.This prospective study included 76 patients with endotracheal intubation for more than 12 h. The leak, in percent, was defined as the difference between expired tidal volume measured just before extubation, in volume-controlled mode, with the cuff inflated and then deflated. The best cut-off value to predict the need for re-intubation for significant laryngeal edema was determined and the patients were divided into two groups, according to this cut-off value.Eight of the 76 patients (11%) needed re-intubation for laryngeal edema. Patients requiring re-intubation had a smaller leak than the other patients [9 (3-18) vs 35 (13-53)%, p0.01]. The best cut-off value for gas leak was 15.5%. The high leak group included 51 patients, of whom only two patients (3%) required re-intubation. The low leak group included 25 patients, among whom six patients (24%) required re-intubation ( p0.01). The sensitivity of this test was 75%, the specificity 72.1%, the positive predictive value 25%, the negative predictive value 96.1% and the percent of correct classification 72.4%.A gas leak around the endotracheal tube greater than 15.5% can be used as a screening test to limit the risk of re-intubation for laryngeal edema.

The purpose of our study was to validate the incentive spirometry (IS) as a simple mean to follow pulmonary function at the bedside after lung surgery.We studied prospectively 19 patients (16 men, 3 women; mean +/- SE age, 60 +/- 2.8 years) undergoing lobectomy for lung cancer. All the patients had an obstructive pattern with FEV1/FVC below 75%. Lung volumes, including functional residual capacity (FRC) and residual volume (RV), measured using spirometry and the helium dilution technique, and IS were measured preoperatively and postoperatively at days 1, 2, 3, and 8, and at 2 months.Our results showed that in the postoperative period after lung resection, IS performance was well correlated (R) during the first 8 postoperative days with vital capacity (VC) (R between 0.667 and 0.870) mainly due to the excellent correlation with the inspiratory reserve volume (IRV, R between 0.680 and 0.895) but was poorly correlated with expiratory reserve volume (R below 0.340), RV (R below 0.180), and FRC (R below 0.470).IS can be used as a simple mean to follow lung function, especially VC and IRV, in the postoperative period in spontaneously breathing patients. IS is noninvasive and can be performed repeatedly at the bedside in the intensive care setting.

Disturbances of cerebral circulation and metabolism play an important role in the pathophysiology of severe head injury. A major concept that has emerged two decades ago is that secondary insults add to primary damage inflicted by trauma, and impair neuronal healing [1]. It is obvious that optimal delivery of oxygen and nutrients to the injured brain is necessary for recovery of primarily damaged but potentially viable neurons, and many secondary insults exert their deleterious effects by impairing this transport. Events such as raised intracranial pressure (ICP), arterial hypotension or hypoxia, and high blood viscosity are more detrimental to cerebral blood flow (CBF) and metabolism than under normal conditions, because the physiological responses and adaptative mechanisms to these stresses may be diminished or absent after traumatic brain injury. These insults may lead to global or regional cerebral ischemia causing neuronal death, while reperfusion of ischemic brain tissue may lead to the generation of oxygen free radicals, which are thought to be involved in the destruction of cell membranes and the development of brain edema [2]. On the other hand, certain states of the cerebral circulation may in themselves be secondary insults; hyperemia due to vascular engorgement leading to increased cerebral blood volume (CBV) may cause brain swelling, and is thought to be important in the development of raised ICP and brainstem distortion, while it may also promote intracerebral bleeding. Therefore, CBF measurement is of key value in the study of the brain circulation and metabolism in patients with head trauma.

Both dobutamine and prostacyclin (PGI2) have been used to increase oxygen delivery in septic patients, but their effects on cerebral blood flow have not been well studied.In 10 septic patients with altered mental status, stable hemodynamic status, and normal lactatemia, we investigated the effects of successive infusions of dobutamine at 5 micrograms/kg/min and PGI2 at 5 ng/kg/min on mean blood flow velocity in a middle cerebral artery, using transcranial Doppler flowmetry.Mean flow velocity increased with dobutamine (from 52 +/- 4 to 62 +/- 6 cm/s, P.005) but not with PGI2 (from 55 +/- 5 to 57 +/- 5 cm/s, P = not significant). Each substance significantly increased cardiac index. Dobutamine increased arterial pressure from 85 +/- 6 to 91 +/- 5 mm Hg (P.05), but PGI2 decreased it from 87 +/- 6 to 77 +/- 5 mm Hg (P.005). With each agent, mean flow velocity was correlated with cardiac index (r = .51, P.001) but not with arterial pressure. PGI2 reduced PaO2 from 103 +/- 10 to 82 +/- 6 mm Hg (P.005). Cerebral oxygen delivery (estimated by the product of mean flow velocity and arterial oxygen content) increased by 19% with dobutamine but remained unchanged with PGI2.Dobutamine and PGI2 at the administered doses exert different effects on arterial pressure and middle cerebral artery flow velocity in septic patients. According to these data, dobutamine increases cerebral oxygen delivery more than PGI2.

Although many critically ill patients suffer from neurological problems, their management does not routinely require monitoring of cerebral circulation. Nevertheless, assessment of cerebral hemodynamics can be of great interest for diagnostic and therapeutic purpose, and for better understanding the pathological processes responsible for cerebral ischemia.

Doppler ultrasound methods are increasingly used in the diagnosis of cervical and intracranial artery diseases. A combination of B-mode can detect the presence and quantify the severity of disease in common and internal carotid, subclavian and vertebral arteries in the neck. Aaslid et al. [1] in 1982 demonstrated that intracranial vessels can be insonated with ultrasound waves through the adult intact skull. In experimented hands, this non-invasive technique is fast, easy, accurate and reproducible, allowing to repeat the measurements as often as desired [2]. Moreover, lightweight and portable equipment facilitates its use in the bedside assessment and monitoring of critically ill patients.

Measurements of toe temperature and transcutaneous PO2 (PtcO2) have been both suggested for non-invasive assessment of peripheral blood flow in acute circulatory failure. The underlying principle of the two methods is that cutaneous vasoconstriction occurs early when tissue perfusion is altered. In 15 patients, we compared the two measurements during cardiogenic shock (27 measurements) or septic shock (29 measurements). Toe-ambiant temperature gradient and PtcO2 correlated well together (r = 0.66, p less than 0.001) especially in hyperkinetic septic shock (r = 0.79, p less than 0.001). In cardiogenic shock, toe-ambiant temperature correlated well with cardiac index (r = 0.63), stroke index (r = 0.64) and oxygen transport (r = 0.65), and these correlations were stronger than for PtcO2. In septic shock, both techniques were poor indicators of blood flow indexes but PtcO2 rather correlated with arterial pressure (r = 0.66) and left ventricular work (r = 0.66). Trend evaluation of data revealed in cardiogenic shock that the increase in toe temperature usually preceded the increase in PtcO2. Since measurement of PtcO2 is technically more complicated, correlates less well with standard hemodynamic parameters and later reflects cardiovascular improvement, it has no advantage over measurement of toe temperature in circulatory shock. In cardiogenic shock, measurements of toe temperature can reliably track cardiac output changes. In septic states, however, non-invasive assessment of skin perfusion is of limited interest.