A pragmatic multi-center trial of goal-directed fluid management based on pulse pressure variation monitoring during high-risk surgery.

BACKGROUND: Intraoperative fluid therapy guided by mechanical ventilation-induced pulse-pressure variation (PPV) may improve outcomes after major surgery. We tested this hypothesis in a multi-center study. METHODS: The patients were included in two periods: a first control period (control group; n = 147) in which intraoperative fluids were given according to clinical judgment. After a training period, intraoperative fluid management was titrated to maintain PPV < 10% in 109 surgical patients (PPV group). We performed 1:1 propensity score matching to ensure the groups were comparable with regard to age, weight, duration of surgery, and type of operation. The primary endpoint was postoperative hospital length of stay. RESULTS: After matching, 84 patients remained in each group. Baseline characteristics, surgical procedure duration and physiological parameters evaluated at the start of surgery were similar between the groups. The volume of crystalloids (4500 mL [3200-6500 mL] versus 5000 mL [3750-8862 mL]; P = 0.01), the number of blood units infused during the surgery (1.7 U [0.9-2.0 U] versus 2.0 U [1.7-2.6 U]; P = 0.01), the fraction of patients transfused (13.1% versus 32.1%; P = 0.003) and the number of patients receiving mechanical ventilation at 24 h (3.2% versus 9.7%; P = 0.027) were smaller postoperatively in PPV group. Intraoperative PPV-based improved the composite outcome of postoperative complications OR 0.59 [95% CI 0.35-0.99] and reduced the postoperative hospital length of stay (8 days [6-14 days] versus 11 days [7-18 days]; P = 0.01). CONCLUSIONS: In high-risk surgeries, PPV-directed volume loading improved postoperative outcomes and decreased the postoperative hospital length of stay. TRIAL REGISTRATION: ClinicalTrials.gov Identifier; retrospectively registered- NCT03128190.

Desenvolvimento e validação de algoritmo para mensuração contínua e ou intermitente das variações da pressão arterial em monitor multiparamétrico: estudo piloto em pacientes de alto risco cirúrgico / Development and validation of an algorithm for continuously and intermittent measurement of arterial pressure in a multiparametric monitor: pilot study in high risk surgical patients

Introdução: Diversos estudos mostraram que maximizar (ou aumentar até se alcançar um platô) o volume sistólico com infusão de fluidos durante uma cirurgia de alto risco pode melhorar o resultado pós-operatório. Este objetivo pode ser atingido simplesmente minimizando-se a variação da pressão arterial (PP) induzida por ventilação mecânica. Testou-se esta hipótese em um único e potencial centro de estudo aleatório. O objetivo principal foi a análise da duração de permanência hospitalar pós-operatória. Métodos: Trinta e três pacientes submetidos a cirurgias de alto risco foram randomizados em grupo controle (Grupo C, n = 16) e grupo intervenção (Grupo I, n = 17). No grupo I, o PP foi continuamente monitorizado durante a cirurgia por um dispositivo automático (DX 2020, Dixtal, São Paulo, Brasil) e minimizado até 10% da variação com infusão adicional de fluidos. Resultados: No período pré-operatório, os Grupos C e I foram comparados com base nos dados demográficos, classificação da American Society of Anesthesiologists (classificação ASA) - Sociedade Americana de Anestesiologistas, tipo e duração da cirurgia. Durante a cirurgia, o Grupo I recebeu mais fluido que o Grupo C (4618 ± 1557 vs 1694 ± 705 ml, p<0,0001), e o PP diminuiu de 22 ± 7 para 9 ± 1% (p < 0,05) no Grupo I. A duração média da permanência hospitalar pós-operatória (7 vs 17 dias, p<0,01) foi menor no Grupo I que no Grupo C. O número de complicações pós-operatória por paciente (1,4 ± 2,1 vs 3,9 ± 2,8, p<0,05), bem como a duração média da ventilação mecânica (1 vs 5 dias, p<0,05) e estadia na Unidade de Terapia Intensiva (UTI) (3 vs 9 dias, p<0,01) também foram mais baixas no Grupo I. Conclusão: Monitorar e minimizar a variação do PP com infusão de fluidos durante cirurgias de alto risco melhorou o resultado pós-operatório e diminuiu a duração da permanência hospitalar. Registro do Estudo: NCT00479011.

Background: Several studies have shown that maximizing (or increasing until reaching a plateau) stroke volume by volume loading during high-risk surgery may improve postoperative outcome. This goal could be achieved simply by minimizing arterial pulse pressure variation (PP) induced by mechanical ventilation. We tested this hypothesis in a prospective, randomised, single centre study. The primary endpoint was the length of postoperative hospital stay. Methods: Thirty-three patients undergoing high-risk surgery were randomized either to a control group (group C, n = 16) or to an intervention group (group I, n = 17). In group I, PP was continuously monitored during surgery by an automatic device (DX 2020, Dixtal, and Sao Paulo, Brazil) and minimized to 10% by volume loading. Results: Pre-operatively, group C and group I were comparable in terms of demographic data, ASA score, type, and duration of surgery. During surgery, group I received more fluid than group C (4618 ± 1557 vs 1694 ± 705 ml, p<0.0001), and PP decreased from 22 ± 7 to 9 ± 1% (p < 0.05) in group I. The median duration of postoperative hospital stay (7 vs 17 days, p<0.01) was lower in group I than in group C. The number of post-operative complications per patient (1.4 ± 2.1 vs 3.9 ± 2.8, p<0.05), as well as the median duration of mechanical ventilation (1 vs 5 days, p<0.05) and ICU stay (3 vs 9 days, p<0.01) was also lower in group I. Conclusion: Monitoring and minimizing PP by volume loading during high-risk surgery improves post-operative outcome and decreases length of hospital. Trial registration: NCT00479011.

Epidemiologia e desfecho de pacientes cirúrgicos não cardíacos em unidades de terapia intensiva no Brasil / Epidemiology and outcomes of non-cardiac surgical patients in Brazilian intensive care units

OBJETIVO: Devido aos avanços da medicina e ao envelhecimento da população, a proporção de pacientes em risco de morte após cirurgias está aumentando. Nosso objetivo foi avaliar o desfecho e a epidemiologia de cirurgias não cardíacas em pacientes admitidos em unidade de terapia intensiva. MÉTODOS: Estudo prospectivo, observacional, de coorte, realizado em 21 unidades de terapia intensiva. Um total de 885 pacientes adultos, cirúrgicos, consecutivamente admitidos em unidades de terapia intensiva no período de abril a junho de 2006 foi avaliado e destes, 587 foram incluídos. Os critérios de exclusão foram; trauma, cirurgias cardíacas, neurológicas, ginecológicas, obstétricas e paliativas. Os principais desfechos foram complicações pós-cirúrgicas e mortalidade na unidade de terapia intensiva e 90 dias após a cirurgia. RESULTADOS: Cirurgias de grande porte e de urgência foram realizadas em 66,4 por cento e 31,7 por cento, dos pacientes, respectivamente. A taxa de mortalidade na unidade de terapia intensiva foi de 15 por cento, e 38 por cento dos pacientes tiveram complicações no pós-operatório. A complicação mais comum foi infecção ou sepse (24,7 por cento). Isquemia miocárdica foi diagnosticada em apenas 1,9 por cento. Um total de 94 por cento dos pacientes que morreram após a cirurgia tinha co-morbidades associadas (3,4 ± 2,2). A principal causa de óbito foi disfunção de múltiplos órgãos (53 por cento). CONCLUSÃO: Sepse é a causa predominante de morbidade em pacientes submetidos a cirurgias não cardíacas. A grande maioria dos óbitos no pós-operatório ocorreu por disfunção de múltiplos órgãos.

OBJECTIVES: Due to the dramatic medical breakthroughs and an increasingly ageing population, the proportion of patients who are at risk of dying following surgery is increasing over time. The aim of this study was to evaluate the outcomes and the epidemiology of non-cardiac surgical patients admitted to the intensive care unit. METHODS: A multicenter, prospective, observational, cohort study was carried out in 21 intensive care units. A total of 885 adult surgical patients admitted to a participating intensive care unit from April to June 2006 were evaluated and 587 patients were enrolled. Exclusion criteria were trauma, cardiac, neurological, gynecologic, obstetric and palliative surgeries. The main outcome measures were postoperative complications and intensive care unit and 90-day mortality rates. RESULTS: Major and urgent surgeries were performed in 66.4 percent and 31.7 percent of the patients, respectively. The intensive care unit mortality rate was 15 percent, and 38 percent of the patients had postoperative complications. The most common complication was infection or sepsis (24.7 percent). Myocardial ischemia was diagnosed in only 1.9 percent of the patients. A total of 94 percent of the patients who died after surgery had co-morbidities at the time of surgery (3.4 ± 2.2). Multiple organ failure was the main cause of death (53 percent). CONCLUSION: Sepsis is the predominant cause of morbidity in patients undergoing non-cardiac surgery. In this patient population, multiple organ failure prevailed as the most frequent cause of death in the hospital.

Epidemiology and outcomes of non-cardiac surgical patients in Brazilian intensive care units. / Epidemiologia e desfecho de pacientes cirúrgicos não cardíacos em unidades de terapia intensiva no Brasil.

OBJECTIVES: Due to the dramatic medical breakthroughs and an increasingly ageing population, the proportion of patients who are at risk of dying following surgery is increasing over time. The aim of this study was to evaluate the outcomes and the epidemiology of non-cardiac surgical patients admitted to the intensive care unit. METHODS: A multicenter, prospective, observational, cohort study was carried out in 21 intensive care units. A total of 885 adult surgical patients admitted to a participating intensive care unit from April to June 2006 were evaluated and 587 patients were enrolled. Exclusion criteria were trauma, cardiac, neurological, gynecologic, obstetric and palliative surgeries. The main outcome measures were postoperative complications and intensive care unit and 90-day mortality rates. RESULTS: Major and urgent surgeries were performed in 66.4% and 31.7% of the patients, respectively. The intensive care unit mortality rate was 15%, and 38% of the patients had postoperative complications. The most common complication was infection or sepsis (24.7%). Myocardial ischemia was diagnosed in only 1.9% of the patients. A total of 94 % of the patients who died after surgery had co-morbidities at the time of surgery (3.4 ± 2.2). Multiple organ failure was the main cause of death (53%). CONCLUSION: Sepsis is the predominant cause of morbidity in patients undergoing non-cardiac surgery. In this patient population, multiple organ failure prevailed as the most frequent cause of death in the hospital.

Volume management in critically ill patients: New insights.

In order to turn a fluid challenge into a significant increase in stroke volume and cardiac output, 2 conditions must be met: 1) fluid infusion has to significantly increase cardiac preload and 2) the increase in cardiac preload has to induce a significant increase in stroke volume. In other words, a patient can be nonresponder to a fluid challenge because preload does not increase during fluid infusion or/and because the heart (more precisely, at least 1 of the ventricles) is operating on the flat portion of the Frank-Starling curve. Volumetric markers of cardiac preload are therefore useful for checking whether cardiac preload effectively increases during fluid infusion. If this is not the case, giving more fluid, using a venoconstricting agent (to avoid venous pooling), or reducing the intrathoracic pressure (to facilitate the increase in intrathoracic blood volume) may be useful for achieving increased cardiac preload. Arterial pulse pressure variation is useful for determining whether stroke volume can/will increase when preload does increase. If this is not the case, only an inotropic drug can improve cardiac output. Therefore, the best option for determining the usefulness of, and monitoring fluid therapy in critically ill patients is the combination of information provided by the static indicators of cardiac preload and arterial pulse pressure variation.

Volume management in critically ill patients: new insights

Para ser efetivo em aumentar significativamente o volume sistólico um volume de fluido precisa preencher duas condições : 1- A infusão deste fluido tem que aumentar a pré-carga; 2- O aumento da pré-carga tem que promover uma elevação proporcional do volume sistólico.Em outras palavras o paciente pode ser não responsivo à infusão de volume em termos de volume sistólico, devido a quantidade de fluidos ainda não ser a necessária ou o coração já estar operando na faixa superior da curva de Frank-Starling. Os indicadores volumétricos da pré-carga cardíaca são úteis para verificar se esta pré-carga aumenta efetivamente durante a infusão de fluido. Em caso negativo, ou seja a pré-carga não aumenta, medidas adicionais como mais fluidos, venoconstrictores para aumentar o quantidade de sangue, ou aumento do retorno venoso por redução da pressão intratorácica podem ser efetivas para atingir a primeira condição: aumento da pré-carga. Delta PP pode ser útil para verificar se o volume sistólico aumenta com a infusão de fluidos. Isto não acontecendo somente drogas inotrópicas podem aumentar o débito cardíaco. Portanto, combinando os indicadores estáticos da pré-carga (PVC, pressão capilar pulmonar) com Delta PP, consegue-se a melhor opção para monitorar a resposta aos fluidos em pacientes críticos.

Variação da pressão sistólica como método diagnóstico da hipovolemia durante anestesia para cirurgia cardíaca / Systolic pressure variation as diagnostic method for hypovolemia during anesthesia for cardiac surgery

JUSTIFICATIVA E OBJETIVOS: A estimativa acurada do volume intravascular efetivo é de grande importância em pacientes submetidos a procedimentos cirúrgicos de grande porte. A avaliação da volemia, baseada na variação da pressão sistólica (VPS), (diferença entre os valores sistólicos máximos e mínimos durante um ciclo respiratório controlado mecanicamente) e sua variável delta down (dDown) tem se mostrado um indicador sensível da pré-carga, quando cotejados com parâmetros hemodinâmicos convencionais. Como a VPS não é um parâmetro utilizado rotineiramente para avaliação da volemia, este trabalho teve como objetivo introduzir a técnica da medida da VPS e verificar sua validade em pacientes submetidos à anestesia para cirurgia cardíaca. MÉTODO: A partir de programa de computador especialmente desenvolvido, transmitiu-se em tempo real a variação da pressão arterial a partir do monitor da sala cirúrgica para microcomputador conectado em rede. Após a adaptação deste sistema, foram estudadas as variações da pressão sistólica em nove pacientes submetidos à revascularização do miocárdio. As variáveis foram registradas em dois momentos, utilizando-se a expansão volêmica como indicador: M0 (antes da expansão volêmica) e M1 (após a expansão volêmica). Também foram estudados alguns parâmetros hemodinâmicos convencionais, confrontados com a variação da pressão sistólica. RESULTADOS: Os principais resultados deste estudo mostram que a VPS, em seu componente dDown, é a que apresenta maior consistência de variação após a expansão volêmica com amido.Os demais parâmetros hemodinâmicos estudados, embora apontem para nítida melhora cardiovascular após a expansão, possuem alta variabilidade entre os pacientes e mesmo quanto à resposta ao expansor. CONCLUSÕES: Os resultados obtidos mostram que a VPS se comporta como um sensível indicador da volemia, em pacientes sob ventilação mecânica, quando correlacionada às variações da pressão venosa central, pressão capilar pulmonar e índice sistólico.

Systolic pressure variation as diagnostic method for hypovolemia during anesthesia for cardiac surgery.

BACKGROUND AND OBJECTIVES: An accurate predictor of effective intravascular volume is of paramount importance for patients submitted to major surgical procedures. A new method to evaluate intravascular volume based on systolic blood pressure variations (SPV), (difference between the maximum and minimum systolic values during controlled respiratory cycle) and its variable delta down (dDown) has shown to be a sensitive indicator of ventricular preload. As SPV is not routinely used in clinical practice our purpose was to evaluate the accuracy of this parameter in evaluating volume status of patients submitted to cardiac surgery. METHODS: As from specially developed software, blood pressure variation was transmitted in real time from operating room monitor to a network-connected computer. After the adaptation of this system, nine patients submitted to cardiac surgery were evaluated. Variables were recorded in two moments: T0 (before volume replacement) and TP (after volume replacement). At the same time, conventional hemodynamic parameters were also studied and compared to systolic pressure variation. RESULTS: Primary study results have shown that SPV (systolic pressure variation), in its dDown component, presents the best variation consistency after volume replacement with starch. Remaining hemodynamic parameters evaluated, although pointing to clear cardiovascular improvement after replacement, are highly variable among the patients and even on expander's response. CONCLUSIONS: Results have shown that SPV is a sensitive method to evaluate intravascular volume status in patients under mechanical ventilation, when correlated to central venous pressure, pulmonary capillary wedge pressure and systolic index variations.

Procalcitonin and C-reactive protein kinetics in postoperative pediatric cardiac surgical patients.

OBJECTIVE: To determine the kinetics of procalcitonin (PCT) and C-reactive protein (CRP) concentration after pediatric cardiac surgery with cardiopulmonary bypass. DESIGN: Prospective, clinical cohort study. SETTING: A fifteen-bed tertiary-care pediatric intensive care unit. PATIENTS: Fourteen pediatric patients admitted for cardiac surgery. MEASUREMENTS AND MAIN RESULTS: Serum PCT and CRP were measured before cardiopulmonary bypass (CPB); after CPB; and on the first, second, and third days after surgery by means of immunoluminometry and nephelometry, respectively. Reference values for systemic inflammatory response syndrome are 0.5 to 2.0 ng/mL for PCT and <5 mg/L for CRP. Baseline serum PCT and CRP concentrations were 0.24 +/- 0.13 ng/mL and 4.06 +/- 3.60 mg/L (median 25th percentile-75th percentile), respectively. PCT concentrations increased progressively from the end of CPB (0.62 +/- 0.30 ng/mL), peaked at 24 hours postoperatively (POD1) (0.77 +/- 0.49 ng/mL), and began to decrease at 48 hours or POD2 (0.35 +/- 0.21 ng/mL). CRP increased just after CPB (58.82 +/- 42.23 mg/L) and decreased after 72 hours (7.09 +/- 9.81 mg/L). CONCLUSION: An increment of both PCT and CRP was observed just after CPB. However, PCT values remained within reference values, whereas CRP concentrations increased significantly after CPB until the third day. These preliminary results suggest that PCT was more effective than CRP to monitor patients with SIRS and a favorable outcome.