Minerva anestesiologica
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Minerva anestesiologica · Apr 2001
Randomized Controlled Trial Clinical TrialAutomated protamine dose assay in heparin reversal management after cardiopulmonary by pass.
To evaluate the impact of automated Protamine Dose Assay (PDA) performed with Hemochron 8000 (International Technodyne Company, Edison, NJ) on the management of heparin reversal after cardiopulmonary bypass (CPB). PDA was compared with empirical protamine to heparin ratio with regard to calculation of the protamine dose, and the sensitivity of PDA and ACT to residual circulating heparin after protamine administration was investigated too. ⋯ PDA allowed us to administer a significantly lower amount of protamine. This can reduce incidence of adverse effects of over- and under-infusion of protamine. PDA also proved to be more sensitive than ACT in detecting residual circulating heparin after protamine administration.
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The role of analgesia and sedation in intensive care units (ICU) is ancillary to other intensive care strategies, nevertheless they permit that every other diagnostic and therapeutic procedure is safely performed by keeping the patient pain-free, anxiety-free and cooperative. Commonly used opioids in ICU include morphine, fentanyl, sufentanil and remifentanil. The choice among opioid drugs relies on their pharmacokinetics and their pharmacodynamic effects. ⋯ The main indications for opioid analgesia and sedation in ICU include: 1) Anxiety, pain and agitation: in turn, they can increase cardiac workload, myocardial oxygen consumption and rate of dysarrhythmias; 2) immediate postoperative period after major surgery; 3) short-term invasive procedures. Potential advantages offered by opioids in the ICU setting also include: a) Cardiac protection: in animal models, it has been observed that delta-opiate receptor stimulation confers a preconditioning-like protective effects against myocardial ischemia; b) Neuroprotection: recent studies suggest that mu- and kappa-opiate receptors are involved in ischemic preconditioning against seizures in the brain. During opioid therapy in the ICU, drug tolerance and withdrawal symptoms should be anticipated and the dose adjusted accordingly.
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The pressure-volume curve of the respiratory system is a physiological method used for diagnotic purposes to describe the static mechanical properties of the respiratory system. A renewal of interest in the pressure-volume curve has recently appeared because of experimental evidence regarding the information conveyed by the curve, a better understanding of the pathophysiologic factors influencing its interpretation and the beneficial results of clinical trials based on the use of the pressure-volume curve for ventilatory management of acute respiratory distress syndrome. Thus, adapting ventilatory settings to individual characteristics of the patients in terms of respiratory mechanics may be an extremely important aspect for a better management of the most difficult to ventilate patients with acute lung injury. ⋯ The low-flow technique using ventilator technology has several potential advantages. It is hopeful to think that in the future the measurement of the P-V curve and the quantification of alveolar recruitment may be easily provided at the bedside and may help for the titration of the ventilatory settings in clinical practice. This review will focus briefly on the physiologic background, technique description, and recent advances concerning the interpretation of the P-V curve in the critically ill patients.
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Minerva anestesiologica · Apr 2001
Review[Physiopathology of acute respiratory failure in COPD and asthma].
Asthma and chronic obstructive pulmonary diseases (COPD) lead to functional obstruction of airways, identified by increased inspiratory and expiratory resistances. Increased expiratory resistances cause, in turn, a reduction in expiratory flow. The analysis of flow-volume loops shows that, as the disease progresses, the flow generated during expiration of a tidal volume becomes very close to the flow generated during forced maximal expiration. ⋯ Ventilatory support of COPD patients should decrease work of breathing and improve gas exchange without increasing hyperinflation. This target can be achieved during assisted ventilation by applying a positive pressure both during inspiration and expiration; the level of PEEP should equal PEEPi. During mechanical ventilation in sedated paralyzed patients hyperinflation should be limited by decreasing minute volume and by increasing expiratory time, eventually choosing controlled hypercapnia.
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Clinical shock is a common problem of the critically ill patient. Assessment of the circulating volume is important to assure adequate oxygen supply to the tissues, and hypovolaemia must be treated promptly to avoid organ dysfunction. ⋯ Clinical signs are often late indicators and the monitoring of hemodynamic variables through cardiac catheterism can be misleading. The fluid challenge approach provides a useful diagnostic test of hypovolaemia, and a method for titrating the dose of fluid tailored to the individual's requirement.