Anesthetic drugs modulate feeding behavior and hypothalamic expression of the POMC polypeptide precursor and the NPY neuropeptide.

BACKGROUND: Several hypnotic drugs have been previously identified as modulators of food intake, but exact mechanisms remain unknown. Feeding behavior implicates several neuronal populations in the hypothalamic arcuate nucleus including orexigenic neuropeptide Y and anorexigenic pro-opiomelanocortin producing neurons. The aim of this study was to investigate in mice the impact of different hypnotic drugs on food consumption and neuropeptide Y or pro-opiomelanocortine mRNA expression level in the hypothalamic arcuate nucleus. METHODS: Saline control, isoflurane, thiopental, midazolam or propofol were administered to C57Bl/6 mice. Feeding behavior was evaluated during 6 h. In situ hybridization of neuropeptide Y and pro-opiomelanocortine mRNAs in the hypothalamus brain region was also performed. Data were analyzed by Kruskal Wallis test and analysis of variance (p < 0.05). RESULTS: Midazolam, thiopental and propofol induced feeding behavior. Midazolam and thiopental increased neuropeptide Y mRNA level (respectively by 106 and 125%, p < 0.001) compared with control. Propofol and midazolam decreased pro-opiomelanocortine mRNA level by 31% (p < 0,01) compared with control. Isoflurane increased pro-opiomelanocortine mRNA level by 40% compared with control. CONCLUSION: In our murine model, most hypnotics induced food consumption. The hypnotic-induced regulation of neuropeptide Y and pro-opiomelanocortine hypothalamic peptides is associated with this finding. Our data suggest that administration of some hypnotic drugs may affect hypothalamic peptide precursor and neuropeptide expression and concomittantly modulate food intake. Thus, this questions the choice of anesthetics for better care management of patients undergoing major surgery or at risk of undernutrition.

[Interaction between hypnotic agents and the hypothalamic-pituitary-adrenocorticotropic axis during surgery]. / Modulation de l'axe hypothalamo-hypophyso-surrénalien par l'utilisation des agents hypnotiques dans le contexte chirurgical.

During stress, the relationship between the central nervous system and the immune system is essential to maintain homeostasis. The main neuroendocrine system involved in this interaction is the hypothalamic-pituitary-adrenal axis (HPA), which via the synthesis of glucocorticoids will modulate the intensity of the inflammatory response. Anaesthetic agents could be interacting with the HPA axis during surgery. Although etomidate currently remains in the center of the discussions, it seems, at least experimentally, that most hypnotics have the capacity to modulate the synthesis of adrenal steroids. Nevertheless, with the large literature on this subject, etomidate seems to be the most deleterious hypnotic agent on the HPA axis function. Its use should be limited when HPA axis is already altered.

Incidence of anaerobic bacteria in patients with suspected pneumonia in surgical Intensive Care Unit.

BACKGROUND: Few studies have investigated the incidence of pulmonary anaerobes in a specific population in surgical Intensive Care Unit (ICU). The objective of this work was to determine the incidence of anaerobes in surgical ICU patients with suspected pneumonia. METHODS: This was a prospective observational, single-center study. Analysis was based on data collected over 30 months from the surgical ICU of a tertiary care hospital (Rouen University Hospital), including data on risk factors for anaerobes in the lungs. Patients with suspected pneumonia (community-acquired or nosocomial) were included. Bacteriological sampling was performed by protected distal bronchial sampling (PDBS) with minilavage under bronchoscopy. Aerobic and anaerobic cultures were performed for each sample. Clinicians were only aware of aerobic results. Univariate and multivariate statistical analysis compared groups with and without anaerobes. RESULTS: A total of 134 samples were obtained from 117 patients. Surgery was performed on 74 patients (63.2%), within 24 hours of admission. Fifty-four patients (46.2%) had a chest trauma and 20 patients (17.1%) were admitted for a digestive pathology. Average age was 53.6±20.9 years and sex ratio was 5.9 (100 men/17 women). Average SAPS II was 41.6±15.1, median length of ICU stay was 23 days (25th percentile=13, 75th percentile=33), and median duration of mechanical ventilation was 21 days (25th percentile=11, 75th percentile=28). Mortality rate in ICU was 14.5%. After sampling, diagnosis of pneumonia was confirmed in 70 cases (52.2%). Anaerobe cultures were positive in 11 samples taken from 11 different patients (overall incidence 8.2%). Aerobic bacteria were also involved in 9 patients (81.8%). In univariate analysis, enteral feeding (P=0.02) and absence of catecholamines at time of sampling (P=0.003) were significantly associated with the presence of anaerobes in PDBS. Enteral nutrition was also found to be a risk factor in multivariate analysis (OR=11.8, 95% CI [1.36 to 102.4] P=0.025). Prior antianaerobic antibiotic treatment was not a protective factor. No difference was observed regarding the notion of aspiration, survival, total length of stay and duration of mechanical ventilation, or evolution of pneumonia between the two groups. CONCLUSION: Our study demonstrates the presence of anaerobic bacteria in the lung samples of patients from surgical ICU with an incidence comparable to that found in populations from medical ICU departments. Anaerobic morbidity in our study is in line with recent literature.

[Hypothermia at admission increases the risk of pulmonary contusion's infection in intubated trauma patients]. / L'hypothermie à l'admission augmente le risque d'infection des contusions pulmonaires chez les patients polytraumatisés sous ventilation invasive.

OBJECTIVES: Pulmonary contusion (PC) is common in cases of polytrauma. The aim of this study was to perform a multivariate analysis of risk factors associated with the occurrence of infection in PC and analyze the microbiological epidemiology. PATIENTS AND METHODS: All patients with PC admitted to the intensive care unit (ICU) between January 2002 and December 2006 were included in this retrospective observational study. Patients with penetrating thoracic trauma or those who died in the 48hours following admission to hospital were excluded. Diagnosis of bacterial infection in PC was performed if hyperthermia was associated with a positive quantitative culture (103 colony forming units/mL) on the bronchial sample. Univariate analysis provided statistical difference between variables that were integrated in the multivariate analysis model. Multivariate analysis was then performed to determine the risk factors of bacterial infection in PC. RESULTS: One hundred and seventeen patients were included. The incidence of bacterial infection in PC was 33.3% (39 patients). The most frequently encountered bacteria were Haemophilus sp., Staphylococcus aureus, Enterobacteriaceae, Pseudomonas sp. and Streptococcus sp. According to multivariate analysis, the existence of hypothermia at hospital admission increased the risk of PC infection (OR=2.61; IC 95% [4.2-13.3]). CONCLUSION: In conclusion, PC was infected in 33.3% of cases. The existence of hypothermia was identified as a risk factor. A prospective study is warranted to confirm these results.