Intensive support recommendations for critically-ill patients with suspected or confirmed COVID-19 infection.

In December 2019, a series of patients with severe pneumonia were identified in Wuhan, Hubei province, China, who progressed to severe acute respiratory syndrome and acute respiratory distress syndrome. Subsequently, COVID-19 was attributed to a new betacoronavirus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Approximately 20% of patients diagnosed as COVID-19 develop severe forms of the disease, including acute hypoxemic respiratory failure, severe acute respiratory syndrome, acute respiratory distress syndrome and acute renal failure and require intensive care. There is no randomized controlled clinical trial addressing potential therapies for patients with confirmed COVID-19 infection at the time of publishing these treatment recommendations. Therefore, these recommendations are based predominantly on the opinion of experts (level C of recommendation).

Initial hepatosplanchnic blood flow distribution and oxygen metabolism in experimental model of hypotensive brain death.

BACKGROUND: Organs from the so-called marginal donors have been used with a significant higher risk of primary non function than organs retrieved from the optimal donors. We investigated the early metabolic changes and blood flow redistribution in splanchnic territory in an experimental model that mimics marginal brain-dead (BD) donor. MATERIAL/METHODS: Ten dogs (21.3+/-0.9 kg), were subjected to a brain death protocol induced by subdural balloon inflation and observed for 30 min thereafter without any additional interventions. Mean arterial and intracranial pressures, heart rate, cardiac output (CO), portal vein and hepatic artery blood flows (PVBF and HABF, ultrasonic flowprobe), and O(2)-derived variables were evaluated. RESULTS: An increase in arterial pressure, CO, PVBF and HABF was observed after BD induction. At the end, an intense hypotension with normalization in CO (3.0+/-0.2 vs. 2.8+/-2.8 L/min) and PVBF (687+/-114 vs. 623+/-130 ml/min) was observed, whereas HABF (277+/-33 vs. 134+/-28 ml/min, p<0.005) remained lower than baseline values. CONCLUSIONS: Despite severe hypotension induced by sudden increase of intracranial pressure, the systemic and splanchnic blood flows were partially preserved without signs of severe hypoperfusion (i.e. hyperlactatemia). Additionally, the HABF was mostly negatively affected in this model of marginal BD donor. Our data suggest that not only the cardiac output, but the intrinsic hepatic microcirculatory mechanism plays a role in the hepatic blood flow control after BD.

Early restoration of cocaine-induced splanchnic hypoperfusion in anesthetized dogs.

Although cardiovascular effects of cocaine have been well studied, little is known about its effects on splanchnic perfusion. We studied systemic and regional hemodynamic effects of acute cocaine intoxication in dogs under volatile anesthesia. Mechanically ventilated beagle dogs, randomized at 1.5% halothane (n = 7) or 2.25% sevoflurane (n = 7) anesthesia, received an intravenous bolus of cocaine (12 mg/kg over 5 min) followed by 0.22 mg/kg/min infusion over 30 min. They were observed for 60 min thereafter. Cardiac index (CI), heart rate (HR), mean arterial pressure (MAP), portal blood flow (PBF), gastric PCO(2) (gas tonometry), blood gases, and lactate and cocaine levels were assessed. Cocaine bolus promoted significant reductions in CI (~50%), HR (~20%), MAP (~20%), and PBF (~50%), accompanied by increase in systemic and splanchnic oxygen extractions and in gastric mucosal-arterial PCO(2) gradient. Those changes were maintained during cocaine infusion and returned to baseline values parallel to plasmatic cocaine clearance. Unlike other shock states, regional parameters, including gastric mucosal-arterial PCO(2) gradient, were restored before systemic variables. A possible local vasodilatory effect of volatile agents could play a role in this phenomenon. Cocaine infusion in anesthetized animals promoted marked systemic and regional hemodynamic derangement, which was rapidly reversible with decay of cocaine plasmatic concentration.

Small volume of hypertonic saline as the initial fluid replacement in experimental hypodynamic sepsis.

INTRODUCTION: We conducted the present study to examine the effects of hypertonic saline solution (7.5%) on cardiovascular function and splanchnic perfusion in experimental sepsis. METHODS: Anesthetized and mechanically ventilated mongrel dogs received an intravenous infusion of live Escherichia coli over 30 minutes. After 30 minutes, they were randomized to receive lactated Ringer's solution 32 ml/kg (LR; n = 7) over 30 minutes or 7.5% hypertonic saline solution 4 ml/kg (HS; n = 8) over 5 minutes. They were observed without additional interventions for 120 minutes. Cardiac output (CO), mean arterial pressure (MAP), portal and renal blood flow (PBF and RBF, respectively), gastric partial pressure of CO2 (pCO2; gas tonometry), blood gases and lactate levels were assessed. RESULTS: E. coli infusion promoted significant reductions in CO, MAP, PBF and RBF (approximately 45%, 12%, 45% and 25%, respectively) accompanied by an increase in lactate levels and systemic and mesenteric oxygen extraction (sO2ER and mO2ER). Widening of venous-arterial (approximately 15 mmHg), portal-arterial (approximately 18 mmHg) and gastric mucosal-arterial (approximately 55 mmHg) pCO2 gradients were also observed. LR and HS infusion transiently improved systemic and regional blood flow. However, HS infusion was associated with a significant and sustained reduction of systemic (18 +/- 2.6 versus 38 +/- 5.9%) and mesenteric oxygen extraction (18.5 +/- 1.9 versus 36.5 +/- 5.4%), without worsening other perfusional markers. CONCLUSION: A large volume of LR or a small volume of HS promoted similar transient hemodynamic benefits in this sepsis model. However, a single bolus of HS did promote sustained reduction of systemic and mesenteric oxygen extraction, suggesting that hypertonic saline solution could be used as a salutary intervention during fluid resuscitation in septic patients.

Intensive support recommendations for critically-ill patients with suspected or confirmed COVID-19 infection / Recomendações de suporte intensivo para pacientes graves com infecção suspeita ou confirmada pela COVID-19

ABSTRACT In December 2019, a series of patients with severe pneumonia were identified in Wuhan, Hubei province, China, who progressed to severe acute respiratory syndrome and acute respiratory distress syndrome. Subsequently, COVID-19 was attributed to a new betacoronavirus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Approximately 20% of patients diagnosed as COVID-19 develop severe forms of the disease, including acute hypoxemic respiratory failure, severe acute respiratory syndrome, acute respiratory distress syndrome and acute renal failure and require intensive care. There is no randomized controlled clinical trial addressing potential therapies for patients with confirmed COVID-19 infection at the time of publishing these treatment recommendations. Therefore, these recommendations are based predominantly on the opinion of experts (level C of recommendation).

RESUMO Em dezembro de 2019, uma série de pacientes com pneumonia grave foi identificada em Wuhan, província de Hubei, na China. Esses pacientes evoluíram para síndrome respiratória aguda grave e síndrome do desconforto respiratório agudo. Posteriormente, a COVID-19 foi atribuída a um novo betacoronavírus, o coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2). Cerca de 20% dos pacientes com diagnóstico de COVID-19 desenvolvem formas graves da doença, incluindo insuficiência respiratória aguda hipoxêmica, síndrome respiratória aguda grave, síndrome do desconforto respiratório agudo e insuficiência renal aguda e requerem admissão em unidade de terapia intensiva. Não há nenhum ensaio clínico randomizado controlado que avalie potenciais tratamentos para pacientes com infecção confirmada pela COVID-19 no momento da publicação destas recomendações de tratamento. Dessa forma, essas recomendações são baseadas predominantemente na opinião de especialistas (grau de recomendação de nível C).

Pulse pressure respiratory variation as an early marker of cardiac output fall in experimental hemorrhagic shock.

Pulse pressure (DeltaPp) and systolic pressure (DeltaPs) variations have been recommended as predictors of fluid responsiveness in critically ill patients. We hypothesized that changes in DeltaPp and DeltaPs parallel alterations in stroke volume (SV) and cardiac output (CO) during hemorrhage, shock, and resuscitation. In anesthetized and mechanically ventilated mongrel dogs, a graded hemorrhage (20 mL/min) was induced to a target mean arterial pressure (MAP) of 40 mm Hg, which was maintained for additional 30 min. Total shed-blood volume was then retransfused at a 40 mL/min rate. CO, SV, right atrial pressure (RAP), pulmonary artery occlusion pressure (PAOP), and continuous mixed venous oxygen saturation (SvO(2)) were assessed. Both DeltaPp and DeltaPs were calculated from direct arterial pressure waveform. Removal of about 9% of estimated blood volume promoted a reduction in SV (14.8 +/- 2.2 to 10.6 +/- 1.3 mL, P < 0.05). At approximately 18% blood volume removal, significant changes in CO (2.4 +/- 0.2 to 1.5 +/- 0.2 mL/min, P < 0.05), DeltaPp (12.6 +/- 1.4 to 15.8 +/- 2.0%, P < 0.05), and SvO(2) (82 +/- 1.4 to 73 +/- 1.7%, P < 0.05) were observed. Alterations in MAP, RAP, PAOP, and DeltaPs could be detected only after each animal had lost over 36% of estimated initial blood volume. There was correlation between blood volume loss and SV, CO, and SvO(2), as well as between blood loss and MAP, DeltaPp, and DeltaPs. Blood volume loss showed no correlation with cardiac filling pressures. DeltaPp is a useful, early marker of SV and CO for the assessment of cardiac preload changes in hemorrhagic shock, while cardiac filling pressures are not.

Efeitos hemodinâmicos sistêmicos e regionais da infusão de cristalóides em modelo experimental de choque séptico hipodinâmico / Regional and systemic hemodynamics effects of crystalloids infusion in an experimental model of hypodynamic septic shock

Para estudar os efeitos hemodinâmicos sistêmicos e regionais da expansão volêmica em modelo de choque séptico, vinte e um cães anestesiados e sob ventilação mecânica receberam dose letal de E. coli vivas por via endovenosa, randomizados em três grupos: Ringer lactato 16 ou 32ml/Kg em 30min ou controle e observados 120min. A bacteremia promoveu hipotensão, redução do débito cardíaco, fluxo porta e renal, acompanhados por aumento da extração sistêmica e regional de oxigênio, acidose láctica e aumento dos gradientes veno-arterial, porta-arterial e gastro-arterial de CO2. A expansão volêmica promoveu benefícios parciais e temporários insuficientes para reverter os déficits perfusionais.To study the regional and systemic hemodynamics effects of fluid resuscitation in a model of septic shock. Twenty-one anesthetized and mechanically ventilated dogs received a lethal doses of live E. coli in blood circulation, randomized in three groups: Lactate Ringer 16 or 32ml/kg in 30 min and control and observed 120 min. The bacteremia resulted in hypotension, decrease of cardiac output, portal and renal flow, accompanied by an increase in the systemic and regional oxygen extraction, lactic acidosis and increase in venous-arterial, porto-arterial and gastro-arterial of CO2 gradients. Fluid replacement resulted in partial and temporary benefits unable to restore the perfusional deficits...