Franco Cavaliere

NEW AGENTS FOR SEDATION IN THE INTENSIVE CARE UNIT

Several advances are likely to benefit the ICU patient requiring sedation, analgesia, and anxiolysis. The cooperative sedation induced by dexmedetomidine is a unique and valuable state that allows patients to be aroused easily and interferes little with ventilation. Remifentanil is the prototype of short-acting drugs, providing fast onset and offset; its relatively high cost may be balanced by limiting the risk for long-lasting respiratory depression. Lorazepam seems to be finding more proponents, especially in long-term ICU sedation where the costs of the newer agents may be prohibitive.

Topical use of tranexamic acid in coronary artery bypass operations: A double-blind, prospective, randomized, placebo-controlled study

OBJECTIVES We sought to investigate the effect of topical application of tranexamic acid into the pericardial cavity in reducing postoperative blood loss in coronary artery surgery. METHODS A prospective, randomized, double-blind investigation with parallel groups was performed. Forty consecutive patients undergoing primary coronary surgery were randomly assigned to group 1 (tranexamic acid group) or group 2 (placebo group). Tranexamic acid (1 g in 100 mL of saline solution) or placebo was poured into the pericardial cavity and over the mediastinal tissues before sternal closure. The drainage of mediastinal blood was measured hourly. RESULTS Chest tube drainage in the first 24 hours was 485 +/- 166 mL in the tranexamic acid group and 641 +/- 184 mL in the placebo group (P =.01). Total postoperative blood loss was 573 +/- 164 mL and 739 +/- 228 mL, respectively (P =.01). The use of banked donor blood products was not significantly different between the two groups. Tranexamic acid could not be detected in any of the blood samples blindly collected from 24 patients to verify whether any systemic absorption of the drug occurred. There were no deaths in either group. None of the patients required reoperation for bleeding. CONCLUSIONS Topical application of tranexamic acid into the pericardial cavity after cardiopulmonary bypass in patients undergoing primary coronary bypass operations significantly reduces postoperative bleeding. Further studies must be carried out to clarify whether a more pronounced effect on both bleeding and blood products requirement might be seen in procedures with a higher risk of bleeding.

A low-dose remifentanil infusion is well tolerated for sedation in mechanically ventilated, critically-ill patients

PurposeTo study the analgesic and sedative effects of remifentanil in critically-ill patients.MethodsRemifentanil infusion was started at 0.02 μg·kg−1·min−1 in ten mechanically ventilated critically-ill patients, and the infusion rate was increased to 0.05, 0.10, 0.15, 0.20, and 0.25 μg·kg−1·min−1 every 30 min. Basally and 25 min after each increase we measured: the Ramsey sedation score (RSS) and the respiratory response subscore of comfort scale (CSRR); the bispectral index (BIS) before and after lightly touching tracheal mucosa; heart rate and systemic arterial pressure; respiratory variables; plasma epinephrine and norepinephrine levels.ResultsInfusion rates up to 0.05 μg·kg−1·min−1 were effective against agitation and achieved a good degree of adaption to the respirator in all patients (RSS 2 or more and CSRR 3 or less); BIS decreased significantly; respiratory and circulatory variables were unaffected; mean plasma epinephrine levels decreased. At infusion rates higher than 0.05 μg·kg−1·min−1 RSS but not BIS decreased further and patient arousability caused by noxious stimuli was not prevented; respiratory drive suppression occurred at the infusion rates higher than 0.05 μg·kg−1·min−1 in four patients; bradycardia and arterial hypotension was observed in three patients; plasma epinephrine levels decreased significantly, while norepinephrine was unaffected; severe itching was experienced by one patient.ConclusionsLow doses of remifentanil (upto 0.05 μg·kg−1·min−1) can be useful in critically-ill patients in order to achieve calm and sedation. Higher doses can inhibit respiratory drive and require controlled mechanical ventilation.ZusammenfassungObjectifÉtudier les effets analgésiques et sédatifs du rémifentanil chez de grands malades.MéthodeUne perfusion de rémifentanil a été amorcée à 0,02 μg·kg−1·min−1 chez dix grands malades ventilés mécaniquement. La vitesse de perfusion a été augmentée à 0,05, 0,10, 0,15, 0,20 et 0,25 μg·kg−1·min−1 toutes les 30 min. Au début, et 25 min après chaque augmentation, nous avons mesuré : les scores de sédation de Ramsey (SSR) et le score auxiliaire de réponse respiratoire de l’échelle de confort (RREC); l’index bispectral (BIS) avant et après avoir légèrement stimulé la muqueuse trachéale; la fréquence cardiaque et la tension artérielle générale; les variables respiratoires; les niveaux plasmatiques d’adrénaline et de noradrénaline.RésultatsLes vitesses de perfusion allant jusqu’à 0,05 μg·kg−1·min−1 ont été efficaces contre l’agitation et ont permis une bonne adaptation au respirateur chez tous les patients (2 ou moins à SSR et 3 ou moins à RREC); le BIS a diminué de manière significative; les variables respiratoires et circulatoires n’ont pas été affectées; il y a eu une baisse des niveaux plasmatiques d’adrénaline et de noradrénaline. Sous des vitesses de perfusion plus élevées que 0,05 μg·kg−1·min−1, le SSR, mais non le BIS, a baissé davantage et la réaction des patients aux stimuli nuisibles n’a pu être empêchée; la suppression de la commande respiratoire s’est produite avec des perfusion audessus de 0,05 μg·kg−1·min−1 chez quatre patients; on a observé de la bradycardie et de l’hypotension chez trois patients; les niveaux plasmatiques d’adrénaline ont baissé significativement, mais ceux de la noradrénaline n’ont pas changé; un prurit sévère a été noté chez un patient.ConclusionDes doses faibles de rémifentanil (jusqu’à 0,05 μg·kg−1·min−1) peuvent apporter calme et sédation chez de grands malades. Des doses plus élevées peuvent inhiber la commande respiratoire et exiger une ventilation mécanique contrôlée.

Sedation with sufentanil in patients receiving pressure support ventilation has no effects on respiration: a pilot study.

PurposeTo evaluate the effects of sedation with sufentanil on respiratory drive, respiratory pattern, and gas exchange of critically ill patients during pressure support ventilation.MethodsIn this prospective observational cohort study, we observed 12 adult patients receiving partial ventilatory support for acute respiratory failure. Each subject received a continuous infusion of sufentanil at 0.2 to 0.3 μg·kg−1·hr−1 to obtain a modified Ramsay sedation score between 2 and 3. In basal conditions and at variable distance from the beginning of the sufentanil infusion (10’, 30’, 60’, 120’, 24 hr) we evaluated gas exchange, hemodynamic variables, respiratory rate (RR), tidal volume (TV), respiratory pattern, respiratory drive (P0.1) and inspiratory impedance of the respiratory system [P0.1 /TV/inspiratory time (Ti)].ResultsThe continuousiv administration of 0.2 to 0.3 μg·kg−1·hr−1 of sufentanil resulted in the desired level of sedation. No significant heart rate, heart rhythm and blood pressure changes were observed. Sufentanil infusion did not affect TV, minute volume, Ti/inspiratory duty cycle, RR, P0.1, P0.1 /TV/Ti and gas exchange did not change significantly over the study period.ConclusionA continuous infusion of sufentanil induces “awake” sedation with no detectable effects on respiratory variables in critically ill patients during partial ventilatory support.RésuméObjectifÉvaluer les effets de la sédation avec sufentanil sur la commande respiratoire, le rythme respiratoire et les échanges gazeux chez les grands malades pendant l’assistance ventilatoire inspiratoire.MéthodeNous avons observé 12 patients adultes sous assistance ventilatoire inspiratoire pour insuffisance respiratoire aiguë dans le cadre d’une étude prospective par observation. Chaque sujet a reçu une perfusion continue de 0,2 à 0,3 μg·kg−1·h−1 de sufentanil pour obtenir un score de sédation de Ramsay modifié entre 2 et 3. Au départ et à intervalles variables après le début de la perfusion de sufentanil (10′, 30′, 60′, 120′, 24 h), nous avons évalué les échanges gazeux, les variables hémodynamiques, la fréquence respiratoire (FR), le volume courant (VC), le rythme respiratoire, la commande respiratoire (P0, 1) et l’impédance inspiratoire du système respiratoire [P0, 1/TV/temps d’inspiration (Ti)].RésultatsL’administration iv continue de 0,2 à 0,3 μg·kg−1·h−1 de sufentanil a produit le niveau désiré de sédation. Aucune modification significative de la fréquence cardiaque, du rythme cardiaque et de la tension artérielle n’a été observée. Le sufentanil n’a pas affecté le VC, la ventilation- minute, le Ti/cycle inspiratoire complet, le RR, la P0, 1, la P0; 1/VC/Ti et les échanges gazeux n’ont pas changé de façon significative au cours de l’étude.ConclusionUne perfusion continue de sufentanil induit une sédation «vigile» sans effets détectables sur les variables respiratoires chez les grands malades pendant l’assistance ventilatoire inspiratoire.

Neuroprotection and Hypothermia in Infants and Children

Brain injury is the leading cause of death in pediatric ICU. Current evidence supports the use of therapeutic hypothermia (TH) in unconscious patients after out-of-hospital cardiac arrest when the initial heart rhythm was ventricular fibrillation. TH has been proved to be also beneficial in term neonates after hypoxic-ischemic encephalopathy (HIE) and in children with traumatic brain injury (TBI). Recent reports have also investigated TH for the treatment of superrefractory status epilepticus. The clinical application of TH is based on the possibility to inhibit or lessen a myriad of destructive processes (including excitotoxicty, neuroinflammation, apoptosis, free radical production, seizure activity, blood- brain barrier disruption, blood vessel leakage) that take place in the injured tissue following ischemia-reperfusion. TH may also represent a useful tool when conventional therapy fails to achieve an effective control of elevated intracranial pressure. This review is aimed to provide an update of the available literature concerning this intriguing topic.

Effects of acute hypoventilation and hyperventilation on exhaled carbon monoxide measurement in healthy volunteers

BackgroundHigh levels of exhaled carbon monoxide (eCO) are a marker of airway or lung inflammation. We investigated whether hypo- or hyperventilation can affect measured values.MethodsTen healthy volunteers were trained to achieve sustained end-tidal CO2 (etCO2) concentrations of 30 (hyperventilation), 40 (normoventilation), and 50 mmHg (hypoventilation). As soon as target etCO2 values were achieved for 120 sec, exhaled breath was analyzed for eCO with a photoacoustic spectrometer. At etCO2 values of 30 and 40 mmHg exhaled breath was sampled both after a deep inspiration and after a normal one. All measurements were performed in two different environmental conditions: A) ambient CO concentration = 0.8 ppm and B) ambient CO concentration = 1.7 ppm.ResultsDuring normoventilation, eCO mean (standard deviation) was 11.5 (0.8) ppm; it decreased to 10.3 (0.8) ppm during hyperventilation (p < 0.01) and increased to 11.9 (0.8) ppm during hypoventilation (p < 0.01). eCO changes were less pronounced than the correspondent etCO2 changes (hyperventilation: 10% Vs 25% decrease; hypoventilation 3% Vs 25% increase). Taking a deep inspiration before breath sampling was associated with lower eCO values (p < 0.01), while environmental CO levels did not affect eCO measurement.ConclusionseCO measurements should not be performed during marked acute hyperventilation, like that induced in this study, but the influence of less pronounced hyperventilation or of hypoventilation is probably negligible in clinical practice

Comparative evaluation of different helmets on patient–ventilator interaction during noninvasive ventilation

R. Costa ( ) · G. Spinazzola · F. Cavaliere · M. Antonelli · R. Proietti · G. Conti Universita Cattolica del Sacro Cuore, Department of Anesthesiology and Intensive Care Medicine, Rome, Italy e-mail: roberta.costa@rm.unicatt.it P. Navalesi Universita Cattolica del Sacro Cuore, Dipartimento di Anestesia e Rianimazione, Centro di Ricerca e Formazione ad Alta Tecnologia nelle Scienze Biomediche, Campobasso, Italy

Furosemide protective effect against airway obstruction.

Furosemide (frusemide) is mainly employed as a powerful diuretic that inhibits Na and K reabsorption in renal tubules. However other valuable pharmacological effects have been discovered that include a protective action from bronchospasm. The effects of furosemide on airways have been recognized to be more and more complex as far as an increasing amount of studies have been produced on this subject. The drug shows no acute bronchodilator effect, but prevents or attenuates bronchospasm caused by many factors, such as hyperpnea, drugs (metabisulphite, bradykinin, AMP), physical agents (hypo- and hypertonic aerosols), and allergen challenge in asthmatic patients. Furosemide is also active on upper airway mucosa, on which the drug decreases nasal resistance in patients affected by non-allergic rhinitis and exhibits a protective effect on nasal mucosa reactivity to the specific allergen in atopic subjects. The mechanism of action of furosemide on airways has not yet been fully cleared and interference with electrolyte epithelial transport, prostaglandins, inflammatory cell activity, vascular and neural regulation has been hypothesized. The interest for clinical application of inhaled furosemide has grown in last years. Some Authors have investigated whether the drug is effective in acute asthma attacks or not. Furosemide is one of the drugs currently used to prevent exercise-induced asthma. More recently, inhaled furosemide has been observed to decrease the sensation of experimentally-induced dyspnea. Apart from possible therapeutic application, studies about furosemide effects on respiratory mucosa can contribute to better understand the physiology of upper and lower airways.

Massive facial edema and airway obstruction secondary to acute postoperative sialadenitis or "anesthesia mumps": a case report

IntroductionA case of massive facial edema and airway obstruction secondary to an acute sialadenitis is described that occurred a few hours after a neurosurgical procedure performed in the prone position. Literature on this topic is reviewed.Case presentationA 73-year-old Caucasian woman underwent a right parieto-occipital craniotomy to remove a meningioma. The procedure was performed in the prone position and lasted for 7 hours. One hour after the end of surgery, left submandibular gland swelling was clearly visible and in a few hours, she developed massive facial edema. Imaging (computed tomography and magnetic resonance) showed inflammatory swelling of the submandibular and parotid glands and of the periglandular tissues, undilated excretory ducts, and complete obliteration of the pharynx lumen (pharyngeal mucosa adhered to the endotracheal tube). Analgesics, corticosteroids, and antibiotics were administered. Edema regressed from the 4th postoperative day and the endotracheal tube could be removed on the 7th postoperative day. The patient was discharged from the surgical intensive care unit on the 14th postoperative day and from hospital on the 28th postoperative day.ConclusionThis is the first case report in which acute postoperative sialadenitis caused complete upper airway obstruction: only the presence of a tracheal tube avoided the need for an emergency tracheostomy. Since edema evolves insidiously, we recommend caution when removing the endotracheal tube in patients who are acutely developing postoperative sialadenitis.

Exposure to noise during continuous positive airway pressure: influence of interfaces and delivery systems.

Background: We measured noise intensity and perceived noisiness during continuous positive airway pressure (CPAP) performed with two interfaces (face‐mask, helmet) and four delivery systems.