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R Bellomo

Publications and source records attributed to R Bellomo.

At least 91 records · Page 5Linked to original sources
PubMed2001

An extracorporeal membrane oxygenation-based approach to cardiogenic shock in an older population.

BACKGROUND: We investigated the efficacy of an integrated system of advanced supportive care based on extracorporeal membrane oxygenation (ECMO) in older patients with an estimated mortality of more than 90% to establish whether its use is justifiable. METHODS: Treatment was provided by cardiac surgeons and critical care physicians and included the following key elements: (1) ECMO, (2) early application of continuous venovenous hemofiltration, (3) inhaled nitric oxide, (4) maintenance of perfusion pressure with norepinephrine, (5) maintenance of pulmonary blood flow by ventricular filling with intravenous colloids, (6) avoidance of early postoperative anticoagulation, (7) frequent use of transesophageal echocardiography, and (8) low tidal volume ventilation. Demographic features, intraoperative details, postoperative course, ECMO weaning rate, morbidity, survival to hospital discharge, and the quality of life of survivors were recorded. RESULTS: Seventeen consecutive patients (median age, 69 years) with refractory cardiogenic shock were studied. The median duration of ECMO was 86 hours (20 to 201 hours). Eleven patients (65%) were successfully weaned from ECMO. Seven patients (41%) survived to discharge. The major causes of morbidity were bleeding and leg ischemia. All patients who survived to discharge were alive and well at follow-up (median, 21 months) and reported a satisfactory quality of life. CONCLUSIONS: An ECMO-based approach can be used with acceptable results in the treatment of refractory cardiogenic shock, even in older patients.

Aged↗
PubMed2001

High lactate predicts the failure of intraaortic balloon pumping after cardiac surgery.

BACKGROUND: Despite the use of intraaortic balloon pump (IABP) support in complex cardiac surgical patients, morbidity and mortality rates are high. More advanced mechanical cardiovascular support should be considered in those patients who are highly likely to die despite IABP support. We sought to identify early, readily available prognostic markers for patients receiving IABP support. METHODS: A retrospective analysis was performed on 39 patients requiring IABP support following cardiac surgery for more than 2 years. The accuracy and predictive ability of multiple potential markers of mortality were statistically assessed. RESULTS: Sixty-seven percent of the patients were successfully weaned from IABP support and 46% survived to hospital discharge. Serious complications occurred in 13% of patients. Serum lactate more than 10 mmol/L in the first 8 hours of IABP support predicted a 100% mortality. Base deficit more than 10 mmol/L, mean arterial pressure less than 60 mm Hg, urine output less than 30 mls/h for 2 hours, and dose of epinephrine or norepinephrine more than 10 microg/min were other highly predictive prognostic markers. CONCLUSIONS: Morbidity and mortality rates remain high despite IABP support following cardiac surgery. Mortality can be predicted by the presence of elevated serum lactate, elevated base deficit, hypotension, oliguria and large vasopressor doses, any of which should prompt appropriate consideration as to other mechanical cardiovascular support.

Aged↗
PubMed2001

Metabolic changes and myocardial injury during cardioplegia: a pilot study.

BACKGROUND: The timing, nature, and severity of both increased cardiac troponin I (cTn-I) levels and myocardial injury during ischemic arrest with cardioplegia are unknown. To define them more accurately, we studied myocardial metabolic activity and the release of markers of myocardial cell injury into the coronary sinus before, during, and after cardioplegia. METHODS: We simultaneously measured creatine kinase, creatine kinase-MB, cTn-I, lactate, phosphate, and blood gases in coronary sinus and systemic arterial blood from 12 patients before cardiopulmonary bypass, after removal of the aortic cross-clamp, and after discontinuation of cardiopulmonary bypass. We also measured coronary sinus flow and transmyocardial fluxes of all analytes and calculated myocardial oxygen consumption, myocardial carbon dioxide production, and myocardial energy expenditure. RESULTS: Myocardial lactate release increased 10-fold after removal of the aortic cross-clamp (p = 0.012) and was accompanied by a surge in myocardial phosphate uptake (p = 0.056). These events were associated with only partial cardioplegia-induced suppression of myocardial oxygen consumption (p = 0.0047), myocardial carbon dioxide production (p = 0.0022), and myocardial energy expenditure (p = 0.0029). Simultaneously, coronary sinus cTn-I levels increased from a mean of 0.76 to 2.43 ng/mL after removal of the aortic cross-clamp, and 2.51 ng/mL after cardiopulmonary bypass (p = 0.014), leading to an increase in arterial cTn-I concentration from 0.18 to 0.98 and 3.01 ng/mL (p = 0.0002). Thus, cTn-I release across the myocardium was absent at baseline, became detectable (p = 0.012) after removal of the aortic cross-clamp, and correlated with cross-clamp and pump times. Similar changes occurred with creatine kinase-MB. CONCLUSIONS: Metabolic myocardial stress occurs during ischemic arrest with cardioplegia and is associated with inadequate suppression of metabolism and with a surge in cTn-I and creatine kinase-MB release, which is maximal after removal of the aortic cross-clamp. These changes are likely to represent structural myocardial cell injury.

Aged↗
PubMed2001

Quantitative physical chemistry analysis of acid-base disorders in critically ill patients.

Compared with the Henderson-Hasselbalch approach, the Stewart approach may better describe the mechanisms of acid-base physiology and disorders. We prospectively examined the acid-base disorders of 100 routine blood samples from critically ill patients using Stewart's physical chemistry analysis. The median results were pH 7.45, PaCO2 5.5 kPa, bicarbonate 27.2 mmol.l-1 and base excess 3 mmol.l-1. The median reference strong ion difference was 46.0 meq.l-1 and the measured median was 45.5 meq.l-1. The median reference total weak-acid concentration was 11.1 mmol.l-1. The measured median total weak-acid concentration was 6.8 mmol.l-1. From Stewart's approach, the most likely explanation for the overall alkalosis was decreased total weak-acid concentration resulting from decreased plasma albumin concentration.

Acid-Base Imbalance↗
PubMed2001

Continuous renal replacement therapy in critically ill patients.

Acute renal failure is an evolving syndrome in which new pathogenetic mechanisms have recently been elucidated. The evolution of the field of haemodialysis has led to a parallel development in the therapeutic approach to patients suffering from this syndrome. In particular, acute renal failure is more frequently seen as part of a more complex syndrome, defined as multiple organ failure. In this clinical setting, patients are almost inevitably confined to intensive care units and sepsis is a frequent underlying mechanism of organ failure. The use of new devices and new machines, together with a better understanding of the underlying mechanisms of solute and water removal, have allowed us to achieve higher levels of efficiency and clinical tolerance during artificial renal replacement therapy. The first objective has been reached by increasing the automation of the extracorporeal circuits and the operational levels of the different techniques; the second has been achieved by means of a new generation of monitoring techniques and new machines equipped with specific interfaces and alarms. This progress has made continuous forms of renal replacement (CRRT) possible and easy to perform without major problems or complications. The most promising and effective options for treating acute renal failure in critically ill patients are today offered by continuous renal replacement therapies. Classic indications, but also alternative non-renal indications, have been proposed for these techniques. The most advanced indication is the multiple organ dysfunction occurring in septic patients. The possible removal of proinflammatory mediators may permit a blockade of the systemic inflammation, a modulation of the altered immune response in these patients, and it may lead to a partial or total restoration of the lost homeostasis.

Acute Kidney Injury↗
PubMed2001

Epidemiology, management, and outcome of severe acute renal failure of critical illness in Australia.

OBJECTIVE: To study the epidemiology, style of management, and outcome of intensive care patients with acute renal failure requiring replacement therapy in Australia. DESIGN: Prospective epidemiologic study. SETTING: Australian adult intensive care units providing acute renal replacement therapy. PATIENTS: Adult intensive care patients with acute renal failure treated with renal replacement therapy. INTERVENTIONS: Demographic and clinical data collection for 3 months. MEASUREMENTS AND MAIN RESULTS: A standardized data collection form for each case of severe acute renal failure was used to collect demographic, biochemical, clinical, and outcome data. Severe acute renal failure affected 299 patients (approximately eight cases per 100,000 adults per year). Among these patients, 99 (33.1%) had impaired baseline renal function, 238 (79.6%) needed mechanical ventilation, and 232 (77.6%) needed continuous vasoactive drug administration. Critical care physicians controlled patient care and renal replacement therapy in 289 cases (96.7%). Critical care nurses performed such therapy alone in 288 (96.3%) cases. Continuous renal replacement therapy was used in 292 (97.7%) patients. There was no nephrological input in 173 (57.8%) cases. Predicted mortality rates were 52.1% by Simplified Acute Physiology Score II, 49.5% by Acute Physiology and Chronic Health Evaluation II score, and 51.9% by an acute renal failure-specific score. Actual mortality rate was 46.8%. Only 25 (15.7%) patients were dialysis-dependent at hospital discharge. Of these patients, 20 (80%) had premorbid chronic impairment of renal function. CONCLUSION: In Australia, critical care physicians and nurses manage severe acute renal failure with limited consultative nephrological input. Renal replacement therapy is continuous and outcomes are satisfactory. Our findings support the view that this approach to management of severe acute renal failure is safe.

Acute Kidney Injury↗
PubMed2001

Importance of increased ultrafiltration volume and impact on mortality: sepsis and cytokine story and the role of continuous veno-venous haemofiltration.

While in end-stage renal disease dialysis dose correlates with morbidity and mortality, this correlation is less evident in acute renal failure. In spite of a poor literature in the field, a few recent papers seem to suggest that an increase in treatment dose may result in an improved outcome of critically ill patients affected by acute renal failure. This improvement appears to plateau at a certain level of dialysis dose in the general population while, in septic patients, the correlation between treatment dose and outcome continues linearly. These results suggest that, while the 'renal dose' of renal replacement therapy has a threshold beyond which further improvements cannot be expected, the 'septic dose' of renal replacement therapy is probably higher and may provide benefits beyond simple blood purification from uremic toxins. This approach is in agreement with the recently proposed 'peak concentration hypothesis', which suggests that sepsis may derive from a complete derangement of the immunological response, featuring simultaneous peaks of pro- and anti-inflammatory mediators. This would explain the systemic inflammatory syndrome and the cell hyporesponsiveness of the septic patient and, at the same time, would explain the beneficial effects of new therapies such as high volume hemofiltration, coupled plasmafiltration adsorption and dialysis with hyperpermeable membranes. These therapies could be able to reduce the peaks of the pro- and anti-inflammatory substances circulating during the syndrome, leading to a less severe degree of inflammation and immunodepression.

Critical Illness↗
PubMed2001

Extracorporeal ultrafiltration for the treatment of overhydration and congestive heart failure.

Fluid overload may occur in patients with congestive heart failure. Under normal conditions, this is treated with inotropic support and diuretics. However, when diuretics fail, fluid removal becomes uncontrolled and other therapeutic options must be undertaken. Extracorporeal ultrafiltration is a possible solution to restore a status of fluid balance close to normal. Several new technologies have made ultrafiltration available today in all centers and easy to be instituted. Acute isolated schedules of ultrafiltration may, however, be too aggressive and result in severe hemodynamic instability. For this reason, continuous extracorporeal techniques have been applied in such patients and the therapy is generally carried out with success. Excellent hemodynamic stability, a good cardiovascular response and often diuresis restoration are the most common effects encountered using continuous forms of extracorporeal fluid removal. The potential for a home-based application of these techniques represents a further stimulating concept to be investigated.

Diuresis↗
PubMed2001

Intensive care unit management of the critically ill patient with fluid overload after open heart surgery.

Fluid overload is common before, during and after cardiac surgery. The fluid associated with cardiopulmonary bypass (CPB) and cardioplegia is a particularly important source of such fluid overload. In addition, renal dysfunction, which is common in these patients, participates in the pathogenesis of a positive sodium and water balance. Such fluid overload is physiologically undesirable and participates in the pathogenesis of several clinically important complications. Fluid overload can be partly prevented with the use of diuretics. However, in many patients, diuretics do not achieve sufficient sodium and water diuresis. In these patients, the application of hemofiltration (HF) during CPB and also immediately after CPB is an effective and safe approach to the maintenance of fluid homeostasis. If acute renal failure occurs, early intervention with HF may even improve survival.

Body Fluids↗
PubMed2001

Hemodynamic response to fluid withdrawal in overhydrated patients treated with intermittent ultrafiltration and slow continuous ultrafiltration: role of blood volume monitoring.

Fluid overload may occur in patients with congestive heart failure, especially when there is associated acute renal failure. When the pharmacological approach is not sufficient to maintain the patient's fluid balance, extracorporeal therapies must be instituted. However, since the ultrafiltration rate may be faster than fluid refilling from the interstitial space, remarkable changes in the circulating blood volume may occur. This may finally result in further worsening of peripheral perfusion due to a significant drop in cardiac output. In order to prevent a fall in the circulating blood volume, slow continuous ultrafiltration (SCUF) should be employed instead of acute intermittent ultrafiltration (UF). To further improve the tolerance to extracorporeal ultrafiltration, the session can be driven by the relative blood volume change monitored on-line with adequate sensors and devices. We utilized one of these systems (Crit-Line, Hemametrics, USA) to compare the relative changes in blood volume during UF and SCUF in 22 patients with fluid overload. Variations in blood pressure were significantly greater with UF than with SCUF even in the presence of similar levels of fluid removal. The variations in blood pressure were paralleled by variations in blood volume, which were greater with UF than with SCUF. In conclusion, extracorporeal ultrafiltration can be used to control the fluid balance in congestive heart failure, but it is advisable to prescribe low ultrafiltration rates over an extended period of time. The use of on-line blood volume monitors can be of further help in improving tolerance and the hemodynamic response.

Acute Kidney Injury↗
PubMed2001

A novel approach to the treatment of chronic fluid overload with a new plasma separation device.

Many patients with congestive heart failure suffer at some point in their therapy from severe fluid overload, and a significant proportion of patients become unresponsive to diuretic drug therapy. In this paper, we propose a new experimental approach to plasma purification and the treatment of severe fluid overload in acute care patients. Plasma can be extracted directly from the patient through an intracorporeal catheter temporarily placed within the inferior vena cava. Plasma separation is accomplished through a proprietary membrane placed on the tip of the catheter. A simple circuit performs plasma removal. The extracted plasma is then available for any type of treatment before being returned to the patient via a second lumen in the same catheter. Plasma flow rates between 3 and 8 ml/min have been achieved and animal tests led to the removal of more than 2,000 ml of plasma water in 24 h. The current varieties of blood purification or ultrafiltration techniques employ extracorporeal extraction of blood from the patient in order to perform treatment. Removal of the cellular component in the extracorporeal fluid circuit may reduce the current problems associated with extracorporeal circuits, such as cellular lysis and viscosity-related problems. Plasma treatment is already successfully performed in a variety of therapies, including renal replacement therapies and plasmapheresis. The therapy proposed here may extend the utility of plasma treatment to the acute cardiology patient. The system could become an important complementary therapy for patients with congestive heart failure for whom classic methods of treatment have failed or simply are not available.

Animals↗
PubMed2001

Extracorporeal blood purification therapy for sepsis and systemic inflammation: its biological rationale.

EBPTs represent a promising new approach to the adjuvant treatment of severe sepsis, septic shock and MODS. Their technology is rapidly evolving and pilot animal and human studies are now taking place to prepare the territory for the first large randomized controlled trial. The rationale for EBPT is reasonable and the initial data are encouraging. The correct technology and molecular targeting, however, are still being explored. Once the best technology has been determined, it is likely that phase II and phase III trials will be performed to test the hypothesis that these therapies can indeed alter mortality in severe inflammatory multiorgan dysfunction.

Critical Illness↗