Normothermic blood polarizing versus depolarizing cardioplegia in a porcine model of cardiopulmonary bypass.

Objectives: We have previously demonstrated beneficial cardiac protection with hypothermic polarizing cardioplegia compared to a hyperkalemic depolarizing cardioplegia. In this study, a porcine model of cardiopulmonary bypass was used to compare the protective effects of normothermic blood-based polarizing and depolarizing cardioplegia during cardiac arrest.

Methods: Thirteen pigs were randomized to receive either normothermic polarizing (n = 8) or depolarizing (n = 5) blood-based cardioplegia.

St Thomas' Hospital polarizing blood cardioplegia improves hemodynamic recovery in a porcine model of cardiopulmonary bypass.

Objective: Cardiac surgery demands highly effective cardioprotective regimens. We previously demonstrated improved cardioprotection with "polarized" compared with "depolarized" arrest. This study uses a clinically relevant porcine model of cardiopulmonary bypass to compare the efficacy of blood-based St Thomas' Hospital polarizing cardioplegia (STH-Pol-B) with blood-based St Thomas' Hospital hyperkalemic cardioplegia (STH2-B).

A comparison of haemostatic biomarkers during low-risk patients undergoing cardiopulmonary bypass using either conventional centrifugal cell salvage or the HemoSep device.

Background: Cardiac surgery using cardiopulmonary bypass (CPB) is associated with a coagulopathy due to haemodilution, thrombocytopenia and platelet dysfunction and the activation of coagulation and fibrinolysis, despite the use of large doses of unfractionated heparin. Conventional red cell salvage may exacerbate post-operative bleeding as plasma containing haemostatic factors is discarded. We hypothesized that a novel cell salvage device (HemoSep) may attenuate haemostatic changes associated with red cell salvage.

Left ventricular dysfunction after two hours of polarizing or depolarizing cardioplegic arrest in a porcine model.

Introduction: This experimental study compares myocardial function after prolonged arrest by St. Thomas' Hospital polarizing cardioplegic solution (esmolol, adenosine, Mg) with depolarizing (hyperkalaemic) St. Thomas' Hospital No 2, both administered as cold oxygenated blood cardioplegia.

Statistical primer: performing repeated-measures analysis.

Longitudinal data arise when repeated measurements are taken on the same individuals over time. Inference about between-group differences of within-subject change is usually of interest. This statistical primer for cardiothoracic and vascular surgeons aims to provide a short and practical introduction of biostatistical methods on how to analyse repeated-measures data.

Efficacy of esmolol cardioplegia during hypothermic ischaemia.

Objectives: Cardioplegic arrest using a polarizing solution has been shown to have beneficial advantages for cardioprotection compared with depolarizing (potassium-based) arrest; most studies, however, have looked at normothermic ischaemia with short infusion intervals (every 10-15 min). This study examines the protective efficacy of an esmolol-based cardioplegia during hypothermic arrest, together with a prolonged infusion interval (30 min) for increased clinical feasibility.

Methods: Isolated Langendorff-perfused hearts were subjected to arrest with St Thomas' Hospital cardioplegia (STH2), or esmolol cardioplegia (single- or multidose infusion at 32°C) for 60-min, 90-min or 120-min global ischaemia at 32°C, and recovery of function (left ventricular developed pressure) measured.

Myocardial energy metabolism and ultrastructure with polarizing and depolarizing cardioplegia in a porcine model.

Objectives: This study investigated whether the novel St. Thomas' Hospital polarizing cardioplegic solution (STH-POL) with esmolol/adenosine/magnesium offers improved myocardial protection by reducing demands for high-energy phosphates during cardiac arrest compared to the depolarizing St. Thomas' Hospital cardioplegic solution No 2 (STH-2).

HEMOlife as a protective additive to Celsior solution for static storage of donor hearts prior to transplantation.

Background: Prior to heart transplantation, static storage of donor hearts is currently limited to 4-5 h, despite profound hypothermia (4-8 °C). Because heart transplantation is an emergency procedure, improved protection to extend safe storage duration would be advantageous. We investigated whether the naturally respiratory pigment HEMOlife, which is effective at hypothermia for the passive release of oxygen via oxygen gradient, could improve long-term preservation.

Myocardial function after polarizing versus depolarizing cardiac arrest with blood cardioplegia in a porcine model of cardiopulmonary bypass.

Objectives: Potassium-based depolarizing St Thomas' Hospital cardioplegic solution No 2 administered as intermittent, oxygenated blood is considered as a gold standard for myocardial protection during cardiac surgery. However, the alternative concept of polarizing arrest may have beneficial protective effects. We hypothesize that polarized arrest with esmolol/adenosine/magnesium (St Thomas' Hospital Polarizing cardioplegic solution) in cold, intermittent oxygenated blood offers comparable myocardial protection in a clinically relevant animal model.

The diagnostic and prognostic significance of monitoring blood levels of immature neutrophils in patients with systemic inflammation.

Introduction: In this cohort study, we investigated whether monitoring blood levels of immature neutrophils (myelocytes, metamyelocytes and band cells) differentiated patients with sepsis from those with the non-infectious (N-I) systemic inflammatory response syndrome (SIRS). We also ascertained if the appearance of circulating immature neutrophils was related to adverse outcome.

Methods: Blood samples were routinely taken from 136 critically ill patients within 48 hours of ICU entry and from 20 healthy control subjects.

Lung injury after simulated cardiopulmonary bypass in an isolated perfused rat lung preparation: Role of mitogen-activated protein kinase/Akt signaling and the effects of theophylline.

Objectives: Lung deflation and inflation during cardiac surgery with cardiopulmonary bypass contributes to pulmonary dysfunction postoperatively. Theophylline treatment for lung diseases has traditionally been thought to act by phosphodiesterase inhibition; however, increasing evidence has suggested other plausible mechanisms. We investigated the effects of deflation and reinflation on signaling pathways (p38-mitogen-activated protein kinase [MAPK], extracellular signal-regulated kinase 1 and 2 [ERK1/2], and Akt) and whether theophylline influences the deflation-induced lung injury and associated signaling.

Future perspective of cardioplegic protection in cardiac surgery.

"Depolarized arrest", induced by hyperkalemic (moderately increased extracellular potassium) cardioplegia is the gold standard to achieve elective temporary cardiac arrest in cardiac surgery. Hyperkalemic cardioplegic solutions provide good myocardial protection, which is relatively safe and easily and rapidly reversible. However, this technique has detrimental effects associated with ionic imbalance involving sodium and calcium overload of the cardiac cell induced by depolarization of the cell membrane.

Cardioprotection with esmolol cardioplegia: efficacy as a blood-based solution.

Objectives: Current cardiac surgery patients are older, sicker, with more diffuse disease and hence a reduced tolerance to ischaemia-reperfusion injury. We previously demonstrated that esmolol, an ultra-short-acting β-blocker, can be used as an arresting agent at high (millimolar) concentrations, and that a crystalloid-based esmolol cardioplegia afforded cardioprotection at least equivalent to hyperkalaemic (St Thomas' Hospital) cardioplegia. Esmolol is rapidly metabolized by blood esterases, so it was important to determine the feasibility of its use in blood-based solutions.

Ischaemic postconditioning: does cardioplegia influence protection?

Objectives: Ischaemic postconditioning attenuates reperfusion injury and may be a useful adjunct to cardiac surgery. We examined the efficacy of postconditioning following ischaemic protection with cardioplegic arrest and the importance of index ischaemia and cardioplegia formulation.

Methods: Isolated Langendorff-perfused rat hearts were subjected to varying durations (30, 45 or 60 min) of global (37°C) ischaemia and then reperfused; functions such as left ventricular developed pressure, left ventricular end-diastolic pressure and heart rate and coronary flow were assessed throughout reperfusion, and infarct size measured after 120 min of reperfusion.

Cardioplegia and cardiac surgery: pharmacological arrest and cardioprotection during global ischemia and reperfusion.

Since the start of cardiac surgery in the 1950s, multiple techniques have been used to protect the heart during the surgical requirement for elective global ischemia (and the still, relaxed, bloodless field that this provides the surgeon for repair of the lesion). Most of these techniques have been discarded. The current gold standard, established over 30 years ago, is hyperkalemic (moderately increased extracellular potassium) cardioplegia; this technique revolutionized cardiac surgery, allowing significant surgical advancement with relative safety.

Esmolol cardioplegia: the cellular mechanism of diastolic arrest.

Aims: Esmolol, an ultra-short-acting beta-blocker, acts as a cardioplegic agent at millimolar concentrations. We investigated the mechanism by which esmolol induces diastolic ventricular arrest.

Methods And Results: In unpaced Langendorff-perfused rat hearts, esmolol (0.

Does intermittent cross-clamp fibrillation provide equivalent myocardial protection compared to cardioplegia in patients undergoing bypass graft revascularisation?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: does intermittent cross-clamp fibrillation provide equivalent myocardial protection compared to cardioplegia in patients undergoing bypass graft revascularisation? Altogether, 58 papers were found using the reported search, of which 13 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated.

Antidepressants and falls in the elderly.

Antidepressants have long been recognized as a contributory factor to falls and many studies show an association between antidepressants and falls. There are extensive data for tricyclic antidepressants (TCAs) and related drugs, and for selective serotonin reuptake inhibitors (SSRIs), but few data for other classes of antidepressants. Sedation, insomnia and impaired sleep, nocturia, impaired postural reflexes and increased reaction times, orthostatic hypotension, cardiac rhythm and conduction disorders, and movement disorders have all been postulated as contributing factors to falls in patients taking antidepressants.