Goal We assessed the relative role of right coronary blood flow versus oxygen extraction ratio (OER) during hemodynamic conditions associated with increased RV oxygen demand as they may occur perioperatively. Background Importance of right ventricular (RV) failure in the perioperative setting: Morbidity and mortality (chronic heart failure, ARDS, PHT) Perioperative mortality higher in RV failure Similar incidence as LV failure RV ≠ LV: Anatomic and physiologic differences
Acute cardiovascular dysfunction occurs perioperatively in more than 20% of cardiosurgical patients, yet current acute heart failure (HF) classification is not applicable to this period. Indicators of major perioperative risk include unstable coronary syndromes, decompensated HF, significant arrhythmias and valvular disease. Clinical risk factors include history of heart disease, compensated HF, cerebrovascular disease, presence of diabetes mellitus, renal insufficiency and high-risk surgery. EuroSCORE reliably predicts perioperative cardiovascular alteration in patients aged less than 80 years. Preoperative B-type natriuretic peptide level is an additional risk stratification factor. Aggressively preserving heart function during cardiosurgery is a major goal. Volatile anaesthetics and levosimendan seem to be promising cardioprotective agents, but large trials are still needed to assess the best cardioprotective agent(s) and optimal protocol(s). The aim of monitoring is early detection and assessment of mechanisms of perioperative cardiovascular dysfunction. Ideally, volume status should be assessed by 'dynamic' measurement of haemodynamic parameters. Assess heart function first by echocardiography, then using a pulmonary artery catheter (especially in right heart dysfunction). If volaemia and heart function are in the normal range, cardiovascular dysfunction is very likely related to vascular dysfunction. In treating myocardial dysfunction, consider the following options, either alone or in combination: low-to-moderate doses of dobutamine and epinephrine, milrinone or levosimendan. In vasoplegia-induced hypotension, use norepinephrine to maintain adequate perfusion pressure. Exclude hypovolaemia in patients under vasopressors, through repeated volume assessments. Optimal perioperative use of inotropes/vasopressors in cardiosurgery remains controversial, and further large multinational studies are needed. Cardiosurgical perioperative classification of cardiac impairment should be based on time of occurrence (precardiotomy, failure to wean, postcardiotomy) and haemodynamic severity of the patient's condition (crash and burn, deteriorating fast, stable but inotrope dependent). In heart dysfunction with suspected coronary hypoperfusion, an intra-aortic balloon pump is highly recommended. A ventricular assist device should be considered before end organ dysfunction becomes evident. Extra-corporeal membrane oxygenation is an elegant solution as a bridge to recovery and/or decision making. This paper offers practical recommendations for management of perioperative HF in cardiosurgery based on European experts' opinion. It also emphasizes the need for large surveys and studies to assess the optimal way to manage perioperative HF in cardiac surgery.
Objectives: Prostacyclin inhalation is increasingly used to treat acute pulmonary hypertension (PHT) and right ventricular (RV) dysfunction. Prostacyclins do not only affect vasomotor tone, but may also exert cyclic-adenosine-3′-5′-monophosphate-mediated positive inotropic effects. We studied the role of these different mechanisms in the hemodynamic effects produced by inhaled iloprost (ILO) in an experimental model of acute PHT.
During one hospital stay, a patient can be cared for by five different units. With patient transfer from one unit to another, it is of prime importance to convey a complete picture of the patient's situation to minimise the risk of medical errors and to provide optimal patient care.This study was designed to test the hypothesis that the implementation of a standardised checklist used during verbal patient handover could improve postoperative data transfer after congenital cardiac surgery.Prospective, pre/postinterventional clinical study.Cardiac centre of a university hospital.Forty-eight patients younger than 16 years undergoing heart surgery.A standardised checklist was developed containing all data that, according to the investigators, should be communicated during the handover of a paediatric cardiac surgery patient from the operating room to the ICU.Data transfer during the postoperative handover before and after implementation of the checklist was evaluated. Duration of handover, number of interruptions, number of irrelevant data and number of confusing pieces of information were noted. Assessment of the handover process by ICU medical and nursing staff was quantified.After implementation of the information transfer checklist, the overall data transfer increased from 48 to 73% (P < 0.001). The duration of data transfer decreased from a median (range) of 6 (2 to 16) to 4 min (2 to 19) (P = 0.04). The overall handover assessment by the intensive care nursing staff improved significantly after implementation of the checklist.Implementation of an information transfer checklist in postoperative paediatric cardiac surgery patients resulted in a more complete transfer of information, with a decrease in the handover duration.
The cellular pathophysiology of renal ischemia-reperfusion injury was investigated in primary cell cultures from rabbit medullary thick ascending limb (MTAL). Metabolic inhibition (MI) was achieved with cyanide and 2-deoxyglucose. Sixty minutes of MI caused a profound but reversible decrease in intracellular concentration of ATP ([ATP]i). Intracellular pH (pHi) first decreased after initiation of MI, followed by a transient alkalinization. When [ATP]i reached its lowest value (<1% of control), the cells slowly acidified to reach a stable pHi of 6.92 after 50 min of MI. In the presence of EIPA (10 micromol/L), the pattern of changes in pHi was unchanged and acidification was not increased, indicating that the Na+/H+ exchangers were inactive during ATP depletion. When inorganic phosphate (P(i)) or Na+ was omitted from the apical solutions during MI, the transient alkalinization was no longer observed and the cytosol slowly acidified. Experiments on Na+-dependent alkalinizations revealed the presence of a Na-P(i) cotransporter in the apical cell membrane. With indirect immunofluorescence, the Na-P(i) cotransporter expressed in these primary cell cultures could be identified as Na-P(i) type I. Although the exact physiological role of Na-P(i) type I still is unresolved, these experiments demonstrate that apical Na-P(i) type I activity is increased at the onset of ATP depletion in MTAL cells.
In patients with sinus rhythm, the magnitude of mechanical ventilation (MV)-induced changes in pulse pressure (PP) is known to predict the effect of fluid loading on cardiac output. This approach, however, is not applicable in patients with atrial fibrillation (AF). We propose a method to isolate this effect of MV from the rhythm-induced chaotic changes in PP in patients with AF. In 10 patients undergoing pulmonary vein ablation for treatment of AF under general anesthesia, ECG and PP waveforms were analyzed during apnea (T1) and during MV at tidal volumes of 8 ml/kg (T2) and 12 ml/kg (T3), respectively. In a first step, three mathematical models were compared in their ability to predict individual PP at T1. The best-fitting model was then selected as the reference to quantify the effects of MV on PP in these patients. A local polynomial regression model based on two preceding RR intervals (LOC2) was found to be superior over the quadratic models to predict PP. LOC2 was therefore selected to quantify variations in PP induced by MV. During T2 and T3, magnitude of PP deviations was related with the amplitude of tidal volume [mean bias error (SD) of -5 (6) and -8 (7) mmHg for T2 and T3, respectively; P = 0.003 repeated-measures ANOVA]. We conclude that LOC2 most accurately predicted rhythm-induced variations in PP. MV-induced deviations in PP can be quantified and may therefore provide a method to study cardiopulmonary interactions in the presence of arrhythmia.
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