Angiotensin II Infusion in COVID-19: An International, Multicenter, Registry-based Study

To expand our understanding of the role of angiotensin II (ANGII) in coronavirus infectious disease 2019 (COVID‐19), we conducted an international, multicenter registry study to assess the use of ANGII in patients with COVID‐19 compared to patients not receiving ANGII. Critically ill adult patients who were diagnosed with COVID‐19 and received ANGII were matched with COVID‐19 patients not receiving ANGII according to age, respiratory support, history of hypertension, use of angiotensin‐converting enzyme inhibitors and/or ANGII receptor blocker, and date of admission. All outcomes were exploratory in nature and included improvement in oxygenation, duration of organ support, and mortality. In one year, 132 patients were included (65 in the ANGII group and 67 in the control group), and patients were comparable in baseline characteristics. During the first 12 h of infusion, patients in the ANGII had a faster decrease in FiO₂ and maintained similar mean arterial pressure levels. Hospital mortality was not statistically significantly different between the groups (53.8% vs. 40.3%; p = 0.226). Within the limitations of such a study design, our findings confirm previous observations of a potentially positive effect of ANGII on blood pressure and FiO₂ but no effect on patient‐centered outcomes.

In patients with coronavirus infectious disease 2019, the physiological effect of angiotensin II (ANGII) on oxygenation was recently assessed in an uncontrolled case series.

During the first 12 h of infusion, patients in the ANGII had a faster decrease in FiO₂ and maintained similar mean arterial pressure levels.

Hospital mortality was not statistically significantly different between the groups.

Cardiac output estimation using pulse wave analysis-physiology, algorithms, and technologies: a narrative review

Pulse wave analysis (PWA) allows estimation of cardiac output (CO) based on continuous analysis of the arterial blood pressure (AP) waveform. We describe the physiology of the AP waveform, basic principles of PWA algorithms for CO estimation, and PWA technologies available for clinical practice. The AP waveform is a complex physiological signal that is determined by interplay of left ventricular stroke volume, systemic vascular resistance, and vascular compliance. Numerous PWA algorithms are available to estimate CO, including Windkessel models, long time interval or multi-beat analysis, pulse power analysis, or the pressure recording analytical method. Invasive, minimally-invasive, and noninvasive PWA monitoring systems can be classified according to the method they use to calibrate estimated CO values in externally calibrated systems, internally calibrated systems, and uncalibrated systems.

A global perspective on vasoactive agents in shock

PURPOSE

We set out to summarize the current knowledge on vasoactive drugs and their use in the management of shock to inform physicians' practices.

METHODS

This is a narrative review by a multidisciplinary, multinational-from six continents-panel of experts including physicians, a pharmacist, trialists, and scientists.

RESULTS AND CONCLUSIONS

Vasoactive drugs are an essential part of shock management. Catecholamines are the most commonly used vasoactive agents in the intensive care unit, and among them norepinephrine is the first-line therapy in most clinical conditions. Inotropes are indicated when myocardial function is depressed and dobutamine remains the first-line therapy. Vasoactive drugs have a narrow therapeutic spectrum and expose the patients to potentially lethal complications. Thus, these agents require precise therapeutic targets, close monitoring with titration to the minimal efficacious dose and should be weaned as promptly as possible. Moreover, the use of vasoactive drugs in shock requires an individualized approach. Vasopressin and possibly angiotensin II may be useful owing to their norepinephrine-sparing effects.

β-Lactam pharmacokinetics during extracorporeal membrane oxygenation therapy: A case-control study

Most adult patients receiving extracorporeal membrane oxygenation (ECMO) require antibiotic therapy, however the pharmacokinetics of β-lactams have not been well studied in these conditions. In this study, data from all patients receiving ECMO support and meropenem (MEM) or piperacillin/tazobactam (TZP) were reviewed. Drug concentrations were measured 2h after the start of a 30-min infusion and just before the subsequent dose. Therapeutic drug monitoring (TDM) results in ECMO patients were matched with those in non-ECMO patients for (i) drug regimen, (ii) renal function, (iii) total body weight, (iv) severity of organ dysfunction and (v) age. Drug concentrations were considered adequate if they remained 4-8× the clinical MIC breakpoint for Pseudomonas aeruginosa for 50% (TZP) or 40% (MEM) of the dosing interval. A total of 41 TDM results (27 MEM; 14 TZP) were obtained in 26 ECMO patients, with 41 matched controls. There were no significant differences in serum concentrations or pharmacokinetic parameters between ECMO and non-ECMO patients, including Vd [0.38 (0.27-0.68) vs. 0.46 (0.33-0.79)L/kg; P=0.37], half-life [2.6 (1.8-4.4) vs. 2.9 (1.7-3.7)h; P=0.96] and clearance [132 (66-200) vs. 141 (93-197)mL/min; P=0.52]. The proportion of insufficient (13/41 vs. 12/41), adequate (15/41 vs. 19/41) and excessive (13/41 vs. 10/41) drug concentrations was similar in ECMO and non-ECMO patients. Achievement of target concentrations of these β-lactams was poor in ECMO and non-ECMO patients. The influence of ECMO on MEM and TZP pharmacokinetics does not appear to be significant.

Vancomycin population pharmacokinetics during extracorporeal membrane oxygenation therapy: a matched cohort study

Introduction

The aim of this study was to describe the population pharmacokinetics of vancomycin in critically ill patients treated with and without extracorporeal membrane oxygenation (ECMO).

Methods

We retrospectively reviewed data from critically ill patients treated with ECMO and matched controls who received a continuous infusion of vancomycin (35 mg/kg loading dose over 4 hours followed by a daily infusion adapted to creatinine clearance, CrCl)). The pharmacokinetics of vancomycin were described using non-linear mixed effects modeling.

Results

We compared 11 patients treated with ECMO with 11 well-matched controls. Drug dosing was similar between groups. The median interquartile range (IQR) vancomycin concentrations in ECMO and non-ECMO patients were 51 (28 to 71) versus 45 (37 to 71) mg/L at 4 hours; 23 (16 to 38) versus 29 (21 to 35) mg/L at 12 hours; 20 (12 to 36) versus 23 (17–28) mg/L at 24 hours (ANOVA, P =0.53). Median (ranges) volume of distribution (Vd) was 99.3 (49.1 to 212.3) and 92.3 (22.4 to 149.4) L in ECMO and non-ECMO patients, respectively, and clearance 2.4 (1.7 to 4.9) versus 2.3 (1.8 to 3.6) L/h (not significant). Insufficient drug concentrations (that is drug levels <20 mg/dL) were more common in the ECMO group. The pharmacokinetic model (non-linear mixed effects modeling) was prospectively validated in five additional ECMO-treated patients over a 6-month period. Linear regression analysis comparing the observed concentrations and those predicted using the model showed good correlation (r² of 0.67; P <0.001).

Conclusions

Vancomycin concentrations were similar between ECMO and non-ECMO patients in the early phase of therapy. ECMO treatment was not associated with significant changes in Vd and drug clearance compared with the control patients.

Using arterial pressure waveform analysis for the assessment of fluid responsiveness

Predicting the effects of volume expansion on cardiac output and oxygen delivery is of major importance in different clinical scenarios. Functional hemodynamic parameters based on pulse waveform analysis, which are relying on the effects of mechanical ventilation on stroke volume and its surrogates, have been shown to be reliable predictors of fluid responsiveness during anesthesia and intensive care unit treatment, as demonstrated by several clinical studies and meta-analyses. However, different limitations of these parameters have to be considered when they are used in clinical practice. Today, they can be continuously and automatically monitored by a variety of commercially available devices. These parameters have been introduced into the concept of perioperative fluid management and hemodynamic optimization - an approach that may positively impact postoperative patients' outcomes. In this article, technical aspects of the assessment of the functional hemodynamic parameters derived from pulse waveform analysis are summarized, emphasizing their advantages, limitations and potential applications, primarily in a perioperative setting in order to improve patient outcome.

[Roles of hydroxyethyl starch solution in resuscitation for shock induced by ischemia/reperfusion injury of the intestine]

OBJECTIVE

To compare the effects of high and low doses of 6% hydroxyethyl starch solution (HES) on resuscitation for shock induced by ischemia/reperfusion injury of the intestine in rabbits.

METHODS

Thirty-two anesthetized rabbits were randomized into four groups of eight animals each. The animals in the control group received no fluid resuscitation, animals in group 2 received lactated Ringer's solution (LRS, 20 ml x kg(-1) x h(-1)), those in group 3 received LRS+HES (LRS 18 ml x kg(-1) x h(1)+HES 2 ml x kg(-1) x h(-1), low dosage of HES), and those in group 4 received HES only in high dosage of HES (20 ml x kg(-1) x h(-1)). All these rabbits underwent intestinal ischemia/reperfusion injury developed by occluding superior mesenteric artery (SMA) with a non-crushing vascular clamp for 60 minutes and then the clamp was loosened for 240 minutes. The fluid resuscitation began at the same time of reperfusion. Hemodynamic parameters including mean artery pressure, heart rate, aortic velocity (as cardiac output), and SMA blood flow were measured. Tissue oxygenation was assessed indirectly by measuring the tonometric parameters of the gut, including difference between partial pressure of carbon dioxide in intestinal intramucosal and partial pressure of carbon dioxide in arterial blood (Pt-aCO(2) gap), intestinal intramucosal pH (pHi), arterial blood lactate acid concentration and oxygen delivery. Mortality of the rabbits was counted at the end of the experiment.

RESULTS

Hemodynamic parameters as measured in low and high doses of HES groups were significantly higher in values than LRS group (LRS) and control (all P<0.05). Low dose of HES was better in restoring hemodynamic parameters than high dose of HES (all P<0.05). Low dose of HES could greatly decrease lactate and Pt-aCO(2) gap, significantly improve pHi compared with other three groups (all P<0.05), but high dose of HES did not do so, and oral and nasal bleeding even death of some animals were seen. Low dose and high dose of HES significantly improved oxygen delivery while LRS did not (all P<0.05).

CONCLUSION

Low dose of HES together with LRS is more effective than only high dose of HES or LRS in the resuscitation for shock induced by ischemia/reperfusion injury of the intestine in rabbits, resulting in better hemodynamic parameters and tissue oxygenation.

The International Sepsis Forum's controversies in sepsis: my initial vasopressor agent in septic shock is dopamine rather than norepinephrine

Norepinephrine (noradrenaline) and dopamine are commonly used first-line vasopressor agents in the treatment of patients with septic shock. Recently increasing interest has focused on whether one or other of these agents is superior in terms of improving outcome. Studies have looked particularly at the possible local effects of the vasopressors on splanchnic circulation, because evidence suggests that this area is important in the development and maintenance of septic shock. However, the many studies performed have yielded conflicting data and there is, as yet, little evidence to support one drug over the other in terms of their splanchnic effects. Overall, though, dopamine has many assets that make it a good first-line drug when compared with norepinephrine, and these are highlighted in the present, brief commentary.