The Eight Unanswered and Answered Questions about the Use of Vasopressors in Septic Shock

Predicting responsiveness to fixed-dose methylene blue in adult patients with septic shock using interpretable machine learning: a retrospective study

This study aimed to develop an interpretable machine learning model to predict methylene blue (MB) responsiveness in adult patients with refractory septic shock and to identify key factors influencing MB responsiveness using the SHapley Additive exPlanations (SHAP) approach. We retrospectively analyzed data from 416 adult patients with refractory septic shock who received MB treatment at Xiangya Hospital of Central South University between June 2018 and October 2022. MB responders were defined as patients who, within 6 hours after MB administration, exhibited either a reduction in average norepinephrine equivalence (NEE) of ≥ 10% or an increase in mean arterial pressure of ≥ 10 mmHg without an associated increase in NEE. The incidence of MB responders was 38.2%(n=159). Statistical and machine learning methods were used for feature selection, resulting in two datasets (ST and ML). Each dataset was randomly divided into a training set (75%) for model development and a testing set (25%) for internal validation. Prediction models were developed using logistic regression, support vector machine (SVM), random forest, light gradient boosting machine (LightGBM), and explainable boosting machine (EBM). The models were evaluated regarding discrimination, calibration, and clinical benefit. The SVM model trained on the ML dataset demonstrated the best predictive performance, with an area under the curve (AUC) of 0.74 (95% CI 0.62-0.84), 76% accuracy, 36% sensitivity, and 94% specificity. Although the model's sensitivity was low, its high specificity and the safety profile of MB underscore its clinical relevance. The model showed superior net benefit within a 24-85% threshold probability, as determined by decision curve analysis. The SHAP analysis identified the average NEE dose within 6 hours before MB initiation as the most important factor influencing MB responsiveness (P<0.01), with higher doses positively correlating with a greater likelihood of response. Lactate levels were identified as the second most important factor. The optimal model was externally validated in an independent cohort from the same institution, achieving an AUC of 0.75 and an accuracy of 74%.

Vasopressor Therapy

Vasopressor therapy represents a key part of intensive care patient management, used to increase and maintain vascular tone and thus adequate tissue perfusion in patients with shock. Norepinephrine is the preferred first-line agent because of its reliable vasoconstrictor effects, with minimal impact on heart rate, and its mild inotropic effects, helping to maintain cardiac output. Whichever vasopressor is used, its effects on blood flow must be considered and excessive vasoconstriction avoided. Other vasoactive agents include vasopressin, which may be considered in vasodilatory states, and angiotensin II, which may be beneficial in patients with high renin levels, although more data are required to confirm this. Dobutamine should be considered, along with continued fluid administration, to help maintain adequate tissue perfusion in patients with reduced oxygen delivery. In this narrative review, we consider the different vasopressor agents, focusing on the importance of tailoring therapy to the individual patient and their hemodynamic response.

The efficacy of hyperbaric oxygen therapy for skin perfusion following peripheral tissue injury due to usage of inotropes and vasopressors: a case report

Hyperbaric oxygen therapy (HBOT) has garnered significant attention as a therapeutic modality with potential benefits across a variety of medical conditions, ranging from wound healing and ischemic conditions to neurologic disorders and radiation-induced tissue damage. HBOT involves the administration of 100% oxygen at higher-than-atmospheric pressures, which increases the amount of oxygen dissolved in body fluids and tissues. Those elevated oxygen levels are proposed to facilitate tissue repair, reduce inflammation, and promote angiogenesis. This case report presents a compelling instance of the usefulness of HBOT in promoting skin perfusion and healing following peripheral tissue injury caused by administration of inotropic and vasopressor agents to a septic shock patient.

A Guide to the Use of Vasopressors and Inotropes for Patients in Shock

Shock is a life-threatening circulatory failure that results in inadequate tissue perfusion and oxygenation. Vasopressors and inotropes are vasoactive medications that are vital in increasing systemic vascular resistance and cardiac contractility, respectively, in patients presenting with shock. To be well versed in using these agents is an important skill to have in the critical care setting where patients can frequently exhibit symptoms of shock. In this review, we will discuss the pathophysiological mechanisms of shock and evaluate the current evidence behind the management of shock with an emphasis on vasopressors and inotropes.

Challenges in Septic Shock: From New Hemodynamics to Blood Purification Therapies

Sepsis and septic shock are associated with high mortality, with diagnosis and treatment remaining a challenge for clinicians. Their management classically encompasses hemodynamic resuscitation, antibiotic treatment, life support, and focus control; however, there are aspects that have changed. This narrative review highlights current and avant-garde methods of handling patients experiencing septic shock based on the experience of its authors and the best available evidence in a context of uncertainty. Following the first recommendation of the Surviving Sepsis Campaign guidelines, it is recommended that specific sepsis care performance improvement programs are implemented in hospitals, i.e., "Sepsis Code" programs, designed ad hoc, to achieve this goal. Regarding hemodynamics, the importance of perfusion and hemodynamic coherence stand out, which allow for the recognition of different phenotypes, determination of the ideal time for commencing vasopressor treatment, and the appropriate fluid therapy dosage. At present, this is not only important for the initial timing, but also for de-resuscitation, which involves the early weaning of support therapies, directed elimination of fluids, and fluid tolerance concept. Finally, regarding blood purification therapies, those aimed at eliminating endotoxins and cytokines are attractive in the early management of patients in septic shock.

Evaluation of the therapeutic efficiency and efficacy of blood purification in the treatment of severe acute pancreatitis

This study aimed to evaluate the therapeutic efficacy and effect of blood purification (BP) therapy on severe acute pancreatitis (SAP). Information on 305 patients (BP group 68, control group 237) diagnosed with SAP was retrieved from the Medical Information Mart for Intensive Care IV (MIMIC IV) database. Firstly, the influence of BP treatment was preliminarily evaluated by comparing the outcome indicators of the two groups. Secondly, multiple regression analysis was used to screen the mortality risk factors to verify the impact of BP on the survival outcome of patients. Then, the effect of BP treatment was re-validated with baseline data. Finally, cox regression was used to make the survival curve after matching to confirm whether BP could affect the death outcome. The results indicated that the BP group had a lower incidence of shock (p = 0.012), but a higher incidence of acute kidney injury (AKI) (p < 0.001), with no differences observed in other outcome indicators when compared to the control group. It was also found that the 28-day survival curve of patients between the two groups was significantly overlapped (p = 0.133), indicating that BP treatment had no significant effect on the survival outcome of patients with SAP. Although BP is beneficial in stabilizing hemodynamics, it has no effect on short- and long-term mortality of patients. The application of this technology in the treatment of SAP should be done with caution until appropriate BP treatment methods are developed, particularly for patients who are not able to adapt to renal replacement therapy.