Factors associated with carbon dioxide transfer in an experimental model of severe acute kidney injury and hypoventilation during high bicarbonate continuous renal replacement therapy and oxygenation membrane support.

OBJECTIVE: To investigate the factors influencing carbon dioxide transfer in a system that integrates an oxygenation membrane in series with high-bicarbonate continuous veno-venous hemodialysis in hypercapnic animals. METHODS: In an experimental setting, we induced severe acute kidney injury and hypercapnia in five female Landrace pigs. Subsequently, we initiated high (40mEq/L) bicarbonate continuous veno-venous hemodialysis with an oxygenation membrane in series to maintain a pH above 7.25. At intervals of 1 hour, 6 hours, and 12 hours following the initiation of continuous veno-venous hemodialysis, we performed standardized sweep gas flow titration to quantify carbon dioxide transfer. We evaluated factors associated with carbon dioxide transfer through the membrane lung with a mixed linear model. RESULTS: A total of 20 sweep gas flow titration procedures were conducted, yielding 84 measurements of carbon dioxide transfer. Multivariate analysis revealed associations among the following (coefficients ± standard errors): core temperature (+7.8 ± 1.6 °C, p < 0.001), premembrane partial pressure of carbon dioxide (+0.2 ± 0.1/mmHg, p < 0.001), hemoglobin level (+3.5 ± 0.6/g/dL, p < 0.001), sweep gas flow (+6.2 ± 0.2/L/minute, p < 0.001), and arterial oxygen saturation (-0.5 ± 0.2%, p = 0.019). Among these variables, and within the physiological ranges evaluated, sweep gas flow was the primary modifiable factor influencing the efficacy of low-blood-flow carbon dioxide removal. CONCLUSION: Sweep gas flow is the main carbon dioxide removal-related variable during continuous veno-venous hemodialysis with a high bicarbonate level coupled with an oxygenator. Other carbon dioxide transfer modulating variables included the hemoglobin level, arterial oxygen saturation, partial pressure of carbon dioxide and core temperature. These results should be interpreted as exploratory to inform other well-designed experimental or clinical studies.

Validation of a low-cost continuous renal replacement therapy dialysate fluid controller for experimental purposes.

BACKGROUND: Continuous renal replacement therapy (CRRT) support is crucial for critically ill patients and it is underexplored in specific situations. Experimental CRRT offers a means to gain insights into these scenarios, but the prohibitive cost of CRRT machines limits their accessibility. This study aimed to develop and validate a low-cost and precise dialysate controller for experimental CRRT. RESULTS: Our results demonstrate a commendable level of precision in affluent flow control, with a robust correlation (R2 = 0.99) for continuous flow and a strong correlation (R2 = 0.95) for intermittent flow. Additionally, we observed acceptable agreement with a bias = 3.4 mL (upper limit 95% = 43.9 mL and lower limit 95% = - 37 mL) for continuous flow and bias = - 20.9 mL (upper limit 95% = 54 mL and lower limit 95% = - 95.7 mL) for intermittent flow, in this way, offering a precise CRRT dose for the subjects. Furthermore, we achieved excellent precision in the cumulative ultrafiltration net (UFnet), with a bias = - 2.8 mL (upper limit 95% = 6.5 mL and lower limit 95% = - 12 mL). These results remained consistent even at low affluent flow rates of 8, 12, and 20 mL/min, which are compatible with CRRT doses of 25-30 mL/kg for medium-sized animals. Moreover, the acceptable precision of our findings persisted when the dialysate controller was subjected to high filter dialysate chamber pressure for an extended duration, up to 797 min. CONCLUSIONS: The low-cost dialysate controller developed and tested in this study offers a precise means of regulating CRRT in experimental settings. Its affordability and accuracy render it a valuable instrument for studying CRRT support in unconventional clinical scenarios, particularly in middle-income countries' experimental ICU laboratories.

Association of fasting in the first 72 h of intensive care unit stay with outcomes of critically ill patients.

BACKGROUND: Whether fasting early in critical illness course is acceptable is not clear and high-quality data on this topic are lacking. To generate equipoise for future clinical trials and bring additional data to current literature, we compared outcomes of patients fasted during the first 72 h of intensive care unit (ICU) stay to patients receiving any nutrition support during this period. METHODS: Retrospective cohort study of a medical ICU from a tertiary academic center in Brazil. Adult patients treated between November 2017 and February 2022 with an ICU length of stay of ≥5 days were included. Baseline and daily data were retrieved from the prospectively collected administrative database. We did 1:1 propensity score matching to compare patients fasting for at least 72 h with controls. Primary outcome was hospital mortality and secondary outcomes were other resources' use. RESULTS: During the study period, 1591 patients were cared for in this ICU, of which 998 stayed ≥5 days. After excluding readmissions and propensity score matching, 93 patients in the fasting group were matched to 93 controls. Hospital mortality was similar between fasting and matched control groups (odds ratio = 1.04; 95% CI = 0.56-1.94; P > 0.99). Secondary outcomes were not different between groups, including length of stay, days on mechanical ventilation, and incidence of new infections. CONCLUSION: Withholding nutrition support in the first 72 h of ICU stay was not associated with worse outcomes in this cohort of severe critically ill patients.

Exploring the association of two oxygenators in parallel or in series during respiratory support using extracorporeal membrane oxygenation. / Investigação da associação de dois oxigenadores em paralelo ou em série durante o suporte respiratório com oxigenação por membrana extracorpórea.

OBJECTIVE: To characterize the pressures, resistances, oxygenation, and decarboxylation efficacy of two oxygenators associated in series or in parallel during venous-venous extracorporeal membrane oxygenation support. METHODS: Using the results of a swine severe respiratory failure associated with multiple organ dysfunction venous-venous extracorporeal membrane oxygenation support model and mathematical modeling, we explored the effects on oxygenation, decarboxylation and circuit pressures of in-parallel and in-series associations of oxygenators. RESULTS: Five animals with a median weight of 80kg were tested. Both configurations increased the oxygen partial pressure after the oxygenators. The return cannula oxygen content was also slightly higher, but the impact on systemic oxygenation was minimal using oxygenators with a high rated flow (~ 7L/minute). Both configurations significantly reduced the systemic carbon dioxide partial pressure. As the extracorporeal membrane oxygenation blood flow increased, the oxygenator resistance decreased initially with a further increase with higher blood flows but with a small clinical impact. CONCLUSION: Association of oxygenators in parallel or in series during venous-venous extracorporeal membrane oxygenation support provides a modest increase in carbon dioxide partial pressure removal with a slight improvement in oxygenation. The effect of oxygenator associations on extracorporeal circuit pressures is minimal.

OBJETIVO: Caracterizar as pressões, as resistências, a oxigenação e a eficácia da descarboxilação de dois oxigenadores associados em série ou em paralelo durante o suporte com oxigenação veno-venosa por membrana extracorpórea. MÉTODOS: Usando os resultados de insuficiência respiratória grave em suínos associada à disfunção de múltiplos órgãos, ao modelo de suporte com oxigenação por membrana extracorpórea veno-venosa e à modelagem matemática, exploramos os efeitos na oxigenação, descarboxilação e pressões do circuito de associações de oxigenadores em paralelo e em série. RESULTADOS: Testaram-se cinco animais com peso mediano de 80kg. Ambas as configurações aumentaram a pressão parcial de oxigênio após os oxigenadores. O teor de oxigênio da cânula de retorno também foi ligeiramente maior, mas o efeito na oxigenação sistêmica foi mínimo, usando oxigenadores com alto fluxo nominal (~ 7L/minuto). Ambas as configurações reduziram significativamente a pressão parcial de dióxido de carbono sistêmico. Como o fluxo sanguíneo na oxigenação por membrana extracorpórea aumentou, a resistência do oxigenador diminuiu inicialmente, com aumento posterior, com fluxos sanguíneos mais altos, mas pouco efeito clínico. CONCLUSÃO: A associação de oxigenadores em paralelo ou em série durante o suporte com oxigenação veno-venosa por membrana extracorpórea proporciona um modesto aumento na depuração da pressão parcial de dióxido de carbono, com leve melhora na oxigenação. O efeito das associações de oxigenadores nas pressões de circuitos extracorpóreos é mínimo.

Adherence to a stress ulcer prophylaxis protocol by critically ill patients: a prospective cohort study. / Adesão a um protocolo de profilaxia de úlcera de estresse em pacientes críticos: estudo de coorte prospectiva.

OBJECTIVE: To evaluate adherence to the stress ulcer prophylaxis protocol in critically ill patients at a tertiary university hospital. METHODS: In this prospective cohort study, we included all adult patients admitted to the medical and surgical intensive care units of an academic tertiary hospital. Our sole exclusion criterion was upper gastrointestinal bleeding at intensive care unit admission. We collected baseline variables and stress ulcer prophylaxis indications according to the institutional protocol and use of prophylaxis. Our primary outcome was adherence to the stress ulcer prophylaxis protocol. Secondary outcomes were appropriate use of stress ulcer prophylaxis, upper gastrointestinal bleeding incidence and factors associated with appropriate use of stress ulcer prophylaxis. RESULTS: Two hundred thirty-four patients were enrolled from July 2nd through July 31st, 2018. Patients were 52 ± 20 years old, 125 (53%) were surgical patients, and the mean SAPS 3 was 52 ± 20. In the longitudinal follow-up, 1499 patient-days were studied; 1069 patient-days had stress ulcer prophylaxis indications, and 777 patient-days contained prophylaxis use (73% stress ulcer prophylaxis protocol adherence). Of the 430 patient-days without stress ulcer prophylaxis indications, 242 involved prophylaxis (56% inappropriate stress ulcer prophylaxis use). The overall appropriate use of stress ulcer prophylaxis was 64%. Factors associated with proper stress ulcer prophylaxis prescription were mechanical ventilation OR 2.13 (95%CI 1.64 - 2.75) and coagulopathy OR 2.77 (95%CI 1.66 - 4.60). The upper gastrointestinal bleeding incidence was 12.8%. CONCLUSION: Adherence to the stress ulcer prophylaxis protocol was low and inappropriate use of stress ulcer prophylaxis was frequent in this cohort of critically ill patients.

Factors associated with carbon dioxide transfer in an experimental model of severe acute kidney injury and hypoventilation during high bicarbonate continuous renal replacement therapy and oxygenation membrane support / Fatores associados à transferência de dióxido de carbono em um modelo experimental de lesão renal aguda grave e hipoventilação durante terapia de substituição renal contínua com alto teor de bicarbonato e suporte com membrana de oxigenação

ABSTRACT Objective To investigate the factors influencing carbon dioxide transfer in a system that integrates an oxygenation membrane in series with high-bicarbonate continuous veno-venous hemodialysis in hypercapnic animals. Methods In an experimental setting, we induced severe acute kidney injury and hypercapnia in five female Landrace pigs. Subsequently, we initiated high (40mEq/L) bicarbonate continuous veno-venous hemodialysis with an oxygenation membrane in series to maintain a pH above 7.25. At intervals of 1 hour, 6 hours, and 12 hours following the initiation of continuous veno-venous hemodialysis, we performed standardized sweep gas flow titration to quantify carbon dioxide transfer. We evaluated factors associated with carbon dioxide transfer through the membrane lung with a mixed linear model. Results A total of 20 sweep gas flow titration procedures were conducted, yielding 84 measurements of carbon dioxide transfer. Multivariate analysis revealed associations among the following (coefficients ± standard errors): core temperature (+7.8 ± 1.6 °C, p < 0.001), premembrane partial pressure of carbon dioxide (+0.2 ± 0.1/mmHg, p < 0.001), hemoglobin level (+3.5 ± 0.6/g/dL, p < 0.001), sweep gas flow (+6.2 ± 0.2/L/minute, p < 0.001), and arterial oxygen saturation (-0.5 ± 0.2%, p = 0.019). Among these variables, and within the physiological ranges evaluated, sweep gas flow was the primary modifiable factor influencing the efficacy of low-blood-flow carbon dioxide removal. Conclusion Sweep gas flow is the main carbon dioxide removal-related variable during continuous veno-venous hemodialysis with a high bicarbonate level coupled with an oxygenator. Other carbon dioxide transfer modulating variables included the hemoglobin level, arterial oxygen saturation, partial pressure of carbon dioxide and core temperature. These results should be interpreted as exploratory to inform other well-designed experimental or clinical studies.

RESUMO Objetivo Investigar os fatores que influenciam a transferência de dióxido de carbono em um sistema que integra uma membrana de oxigenação em série com terapia de substituição renal contínua com alto teor de bicarbonato em animais hipercápnicos. Métodos Em um ambiente experimental, induzimos lesão renal aguda grave e hipercapnia em cinco porcos Landrace fêmeas. Em seguida, iniciamos terapia de substituição renal contínua com alto teor de bicarbonato (40mEq/L) com uma membrana de oxigenação em série para manter o pH acima de 7,25. Em intervalos de 1 hora, 6 horas e 12 horas após o início da terapia de substituição renal contínua, realizamos uma titulação padronizada do fluxo de gás de varredura para quantificar a transferência de dióxido de carbono. Avaliamos os fatores associados à transferência de dióxido de carbono através da membrana pulmonar com um modelo linear misto. Resultados Realizamos 20 procedimentos de titulação do fluxo de gás de varredura, produzindo 84 medições de transferência de dióxido de carbono. A análise multivariada revelou associações entre os seguintes itens (coeficientes ± erros padrão): temperatura central (+7,8 ± 1,6 °C, p < 0,001), pressão parcial pré-membrana de dióxido de carbono (+0,2 ± 0,1mmHg, p < 0,001), nível de hemoglobina (+3,5 ± 0,6g/dL, p < 0,001), fluxo de gás de varredura (+6,2 ± 0,2L/minuto, p < 0,001) e saturação de oxigênio (-0,5% ± 0,2%, p = 0,019). Entre essas variáveis, e dentro das faixas fisiológicas avaliadas, o fluxo do gás de varredura foi o principal fator modificável que influenciou a eficácia da remoção de dióxido de carbono de baixo fluxo sanguíneo. Conclusão O fluxo do gás de varredura é a principal variável relacionada à remoção de dióxido de carbono durante a terapia de substituição renal contínua com um alto nível de bicarbonato acoplado a um oxigenador. Outras variáveis moduladoras da transferência de dióxido de carbono incluíram o nível de hemoglobina, a saturação de oxigênio, a pressão parcial de dióxido de carbono e a temperatura central. Esses resultados devem ser interpretados como exploratórios para informar outros estudos experimentais ou clínicos bem planejados.

Investigação da associação de dois oxigenadores em paralelo ou em série durante o suporte respiratório com oxigenação por membrana extracorpórea / Exploring the association of two oxygenators in parallel or in series during respiratory support using extracorporeal membrane oxygenation

RESUMO Objetivo: Caracterizar as pressões, as resistências, a oxigenação e a eficácia da descarboxilação de dois oxigenadores associados em série ou em paralelo durante o suporte com oxigenação veno-venosa por membrana extracorpórea. Métodos: Usando os resultados de insuficiência respiratória grave em suínos associada à disfunção de múltiplos órgãos, ao modelo de suporte com oxigenação por membrana extracorpórea veno-venosa e à modelagem matemática, exploramos os efeitos na oxigenação, descarboxilação e pressões do circuito de associações de oxigenadores em paralelo e em série. Resultados: Testaram-se cinco animais com peso mediano de 80kg. Ambas as configurações aumentaram a pressão parcial de oxigênio após os oxigenadores. O teor de oxigênio da cânula de retorno também foi ligeiramente maior, mas o efeito na oxigenação sistêmica foi mínimo, usando oxigenadores com alto fluxo nominal (~ 7L/minuto). Ambas as configurações reduziram significativamente a pressão parcial de dióxido de carbono sistêmico. Como o fluxo sanguíneo na oxigenação por membrana extracorpórea aumentou, a resistência do oxigenador diminuiu inicialmente, com aumento posterior, com fluxos sanguíneos mais altos, mas pouco efeito clínico. Conclusão: A associação de oxigenadores em paralelo ou em série durante o suporte com oxigenação veno-venosa por membrana extracorpórea proporciona um modesto aumento na depuração da pressão parcial de dióxido de carbono, com leve melhora na oxigenação. O efeito das associações de oxigenadores nas pressões de circuitos extracorpóreos é mínimo.

ABSTRACT Objective: To characterize the pressures, resistances, oxygenation, and decarboxylation efficacy of two oxygenators associated in series or in parallel during venous-venous extracorporeal membrane oxygenation support. Methods: Using the results of a swine severe respiratory failure associated with multiple organ dysfunction venous-venous extracorporeal membrane oxygenation support model and mathematical modeling, we explored the effects on oxygenation, decarboxylation and circuit pressures of in-parallel and in-series associations of oxygenators. Results: Five animals with a median weight of 80kg were tested. Both configurations increased the oxygen partial pressure after the oxygenators. The return cannula oxygen content was also slightly higher, but the impact on systemic oxygenation was minimal using oxygenators with a high rated flow (~ 7L/minute). Both configurations significantly reduced the systemic carbon dioxide partial pressure. As the extracorporeal membrane oxygenation blood flow increased, the oxygenator resistance decreased initially with a further increase with higher blood flows but with a small clinical impact. Conclusion: Association of oxygenators in parallel or in series during venous-venous extracorporeal membrane oxygenation support provides a modest increase in carbon dioxide partial pressure removal with a slight improvement in oxygenation. The effect of oxygenator associations on extracorporeal circuit pressures is minimal.

Sepsis in intensive care unit patients with traumatic brain injury: factors associated with higher mortality.

OBJECTIVE: Patients with traumatic brain injury are particularly susceptible to sepsis, which may exacerbate the systemic inflammatory response and lead to organ dysfunction. The influence of clinical variables on the mortality of intensive care unit patients with traumatic brain injury and sepsis was investigated. METHODS: The present investigation was a retrospective study involving 175 patients with traumatic brain injury who were treated in a period of 1 year at a reference hospital for trauma and who had sepsis, severe sepsis, or septic shock. Demographic and clinical data were obtained, and the SOFA score was calculated at the time sepsis was found and after 72 hours. RESULTS: There was a predominance of young men with severe traumatic brain injury, multiple head injuries, sepsis with a pulmonary focus, prolonged hospital stay, and high mortality (37.7%). Circulatory and respiratory failure had a high incidence, but renal and coagulation failure were less frequent, and liver failure was not observed. After logistic regression, the presence of septic shock and respiratory failure 72 hours after the sepsis diagnosis was associated with higher mortality, with an odds ratio of 7.56 (95%CI=2.04-27.31, p=0.0024) and 6.62 (95%CI=1.93-22.78, p=0.0027), respectively. In addition, there was a higher mortality among patients who had no organ failure on D1 but who developed the condition after 72 hours of sepsis and in those patients who already had organ failure at the time sepsis was diagnosed and remained in this condition after 72 hours. CONCLUSION: Septic shock and progressive organ (particularly respiratory) dysfunction increases the mortality of patients with traumatic brain injury and sepsis.

Sepse em pacientes com traumatismo craniencefálico em unidade de terapia intensiva: fatores relacionados à maior mortalidade / Sepsis in intensive care unit patients with traumatic brain injury: factors associated with higher mortality

Objetivo: Pacientes com traumatismo craniencefálico são particularmente suscetíveis a sepse, a qual pode exacerbar a resposta inflamatória sistêmica e levar à disfunção orgânica. Investigou-se a influência de variáveis clínicas sobre a mortalidade de pacientes com traumatismo craniencefálico e sepse em unidade de terapia intensiva. Métodos: Trata-se de estudo retrospectivo envolvendo 175 pacientes com traumatismo craniencefálico atendidos durante 1 ano em um hospital de referência em trauma, que apresentaram sepse, sepse grave ou choque séptico. Foram obtidos dados demográficos e clínicos e foi aferida a pontuação no escore SOFA no momento da identificação da sepse e após 72 horas. Resultados: Observou-se predomínio de homens jovens, com traumatismo craniencefálico grave, múltiplas lesões cranianas, sepse de foco pulmonar, tempo de internação prolongado e alta mortalidade (37,7%). Falência respiratória e circulatória tiveram alta incidência, já falência renal e da coagulação foram menos frequentes e não se registrou falência hepática. Após a regressão logística, a presença de choque séptico e falência respiratória após 72 horas da identificação da sepse foram associados à maior mortalidade, com odds ratio de 7,56 (IC95%=2,04-27,31; p=0,0024) e 6,62 (IC95%=1,93-22,78; p=0,0027), respectivamente. Ainda, houve maior mortalidade nos pacientes que não possuíam falência orgânica em D1, mas que desenvolveram após 72 horas do diagnóstico de sepse e naqueles que já tinham falência orgânica no momento do diagnóstico da sepse e permaneceram assim após 72 horas. Conclusão: Choque séptico e disfunção orgânica ...

Objective: Patients with traumatic brain injury are particularly susceptible to sepsis, which may exacerbate the systemic inflammatory response and lead to organ dysfunction. The influence of clinical variables on the mortality of intensive care unit patients with traumatic brain injury and sepsis was investigated. Methods: The present investigation was a retrospective study involving 175 patients with traumatic brain injury who were treated in a period of 1 year at a reference hospital for trauma and who had sepsis, severe sepsis, or septic shock. Demographic and clinical data were obtained, and the SOFA score was calculated at the time sepsis was found and after 72 hours. Results: There was a predominance of young men with severe traumatic brain injury, multiple head injuries, sepsis with a pulmonary focus, prolonged hospital stay, and high mortality (37.7%). Circulatory and respiratory failure had a high incidence, but renal and coagulation failure were less frequent, and liver failure was not observed. After logistic regression, the presence of septic shock and respiratory failure 72 hours after the sepsis diagnosis was associated with higher mortality, with an odds ratio of 7.56 (95%CI=2.04-27.31, p=0.0024) and 6.62 (95%CI=1.93-22.78, p=0.0027), respectively. In addition, there was a higher mortality among patients who had no organ failure on D1 but who developed the condition after 72 hours of sepsis and in those patients who already had organ failure at the time sepsis was diagnosed and remained in this condition after 72 hours. Conclusion: Septic shock and progressive organ (particularly respiratory) dysfunction increases the mortality of patients with traumatic brain injury and sepsis. .

Fatores de risco em pacientes com aneurismas intracranianos atendidos em um hospital de referência de Belém-PA / Risk factors in patients presenting with intracranial aneurysms assisted in a reference hospital in Belém-PA

Objetivo: Este estudo visa averiguar a influência de fatores de risco sobre a mortalidade no tratamento de aneurismas. Método: estudo retrospectivo, transversal e quantitativo com pacientes atendidos entre Janeiro de 2001 a Dezembro de 2010 em virtude de aneurismas cerebrais no Hospital Ophir Loyola. Prontuários foram utilizados como fonte para coleta de dados sócio-demográficos, sobre fatores de risco e sobre o aneurisma. Foi realizada análise descritiva seguida pelo cálculo do risco relativo de cada variável em relação ao tipo de alta. Resultados: Dentre 123 pacientes com 158 aneurismas, 72,36% eram mulheres, a idade média foi 46,5 ± 12,7, 38,21% eram hipertensos, 5,69% diabéticos, 21,95% tinha múltiplos aneurismas, 87,80% foram tratados de forma intervencionista, a taxa de letalidade foi de 12,20% e 90,24% dos aneurismas tinha sítio na circulação anterior. O risco relativo de morte foi de 5,14 para o tratamento conservador em relação ao intervencionista e 4,02 para os com 60 anos ou mais em relação aos que tinham menos de 60 anos. Conclusão: Considerando as características dos pacientes deste estudo sugere-se a necessidade de pesquisas que avaliem a eficácia da triagem em pacientes com risco, detectando os aneurismas antes de sua ruptura e modificando a história natural desta doença.