[Alpha-2 adrenoreceptor agonists for the intensive care physician]. / Les agonistes α2-adrénergiques pour l'intensiviste.

Clonidine and dexmedetomidine are two α2-adrenoreceptors agonists available for the intensivist in the clinical practice. The affinity of dexmedetomidine is eight times greater than clonidine affinity for the α2 receptors. Their main effect is sedation. They act by inhibition of noradrenaline release in the locus coeruleus in the brainstem. α2-agonists are used primarily for sedation, analgesia, and management of delirium. Nowadays, dexmedetomidine application is increasing in critically ill patients showing a good safety. Most frequent side effects include bradycardia and hypotension.

En pratique clinique, l'intensiviste dispose de deux α2-agonistes, à savoir la clonidine et la dexmédétomidine. L'affinité de la dexmédétomidine pour les récepteurs α2-adrénergiques est huit fois plus importante que celle de la clonidine. Leur principal effet est la sédation. Cet effet est obtenu par inhibition de la libération de noradrénaline dans le locus cœruleus du tronc cérébral. Ces molécules sont surtout utilisées pour la sédation, l'analgésie et la prise en charge du delirium chez le patient critique. Le recours à la dexmédétomidine augmente actuellement et montre une bonne sécurité de la molécule. Les effets indésirables les plus fréquents sont la bradycardie et l'hypotension.

Effect of postoperative haemoglobin variation on major cardiopulmonary complications in high cardiac risk patients undergoing anatomical lung resections.

OBJECTIVES: Recent evidence shows that permissive anaemia strategies are safe in different surgical settings. However, effects of variations in haemoglobin (Hb) levels could have a negative impact in high-risk patients. We investigated the combined effect of postoperative Hb concentration and cardiac risk status on major cardiopulmonary complications after anatomical lung resections. METHODS: We retrospectively analysed the records, collected in a prospective clinical database, of 154 consecutive patients undergoing anatomical lung resections at our institution (February 2017-February 2019). Hb levels were displayed as preoperative concentration, nadir Hb level before onset of complications and delta Hb (ΔHb). Cardiac risk was stratified according to the Thoracic Revised Cardiac Risk Index (ThRCRI). Univariable and multivariable logistic regression analyses were used to test the associations between patients, surgical variables and cardiopulmonary complications according to the European Society of Thoracic Surgeons definitions. RESULTS: Cardiopulmonary complications occurred in 63 patients (17%). In the fully adjusted multivariable model, higher values of ΔHb were associated with increased risk of complications [odds ratio (OR) 1.07; P < 0.001], along with higher ThRCRI classes (classes A-B versus C-D: OR 0.09; P < 0.001). Interaction terms with transfusion were not statistically significant, indicating that the harmful effect of ΔHb was independent. According to receiver operating characteristic curve analysis, a ΔHb of 29 g/l was found to be the best cut-off value for predicting complications. CONCLUSIONS: In our series, ΔHb, rather than nadir Hb, was associated with an increased risk of complications, particularly in patients with higher cardiac risk. Restrictive transfusion strategies should be carefully applied in patients undergoing lung resections and balanced according to individual clinical status.