Nitroglycerin reverts clinical manifestations of poor peripheral perfusion in patients with circulatory shock

Local carbachol application induces oral microvascular recruitment and improves gastric tissue oxygenation during hemorrhagic shock in dogs

Introduction

Hemorrhagic shock is characterized by derangements of the gastrointestinal microcirculation. Topical therapy with nitroglycerine or iloprost improves gastric tissue oxygenation but not regional perfusion, probably due to precapillary adrenergic innervation. Therefore, this study was designed to investigate the local effect of the parasympathomimetic carbachol alone and in combination with either nitroglycerine or iloprost on gastric and oral microcirculation during hemorrhagic shock.

Methods

In a cross-over design five female foxhounds were repeatedly randomized into six experimental groups. Carbachol, or carbachol in combination with either nitroglycerine or iloprost were applied topically to the oral and gastric mucosa. Saline, nitroglycerine, or iloprost application alone served as control groups. Then, a fixed-volume hemorrhage was induced by arterial blood withdrawal followed by blood retransfusion after 1h of shock. Gastric and oral microcirculation was determined using reflectance spectrophotometry and laser Doppler flowmetry. Oral microcirculation was visualized with videomicroscopy. Statistics: 2-way-ANOVA for repeated measurements and Bonferroni post-hoc analysis (mean ± SEM; p < 0.05).

Results

The induction of hemorrhage led to a decrease of gastric and oral tissue oxygenation, that was ameliorated by local carbachol and nitroglycerine application at the gastric mucosa. The sole use of local iloprost did not improve gastric tissue oxygenation but could be supplemented by local carbachol treatment. Adding carbachol to nitroglycerine did not further increase gastric tissue oxygenation. Gastric microvascular blood flow remained unchanged in all experimental groups. Oral microvascular blood flow, microvascular flow index and total vessel density decreased during shock. Local carbachol supply improved oral vessel density during shock and oral microvascular flow index in the late course of hemorrhage.

Conclusion

The specific effect of shifting the autonomous balance by local carbachol treatment on microcirculatory variables varies between parts of the gastrointestinal tract. Contrary to our expectations, the improvement of gastric tissue oxygenation by local carbachol or nitroglycerine application was not related to increased microvascular perfusion. When carbachol is used in combination with local vasodilators, the additional effect on gastric tissue oxygenation depends on the specific drug combination. Therefore, modulation of tissue oxygen consumption, mitochondrial function or alterations in regional blood flow distribution should be investigated.

Anesthesia management of patients undergoing off-pump coronary artery bypass grafting: A retrospective study of single center

Background

To summarize the current practice of anesthesia management for Chinese patients undergoing off-pump coronary artery bypass (OPCAB) surgery at a large-volume cardiovascular center.

Materials and methods

The clinical data of consecutive patients undergoing isolated, primary OPCAB surgery during the period from September 2019 to December 2019 were retrospectively analyzed. Patient characteristics, intraoperative data, and short-term outcomes were extracted from the Hospital Information System and the Anesthesia Information Management System.

Results

A total of 255 patients who underwent OPCAB surgery were enrolled in the current study. High-dose opioids and short-acting sedatives were the most commonly administrated anesthetics intraoperatively. Pulmonary arterial catheter insertion is frequently performed in patients with serious coronary heart disease. Goal-directed fluid therapy, a restricted transfusion strategy, and perioperative blood management were routinely used. Rational usages of inotropic and vasoactive agents facilitate hemodynamic stability during the coronary anastomosis procedure. Four patients underwent re-exploration for bleeding, but no death was observed.

Conclusions

The study introduced the current practice of anesthesia management at the large-volume cardiovascular center, and the short-term outcomes indicated the efficacy and safety of the practice in OPCAB surgery.

EFFECTS OF SHENFU INJECTION ON SUBLINGUAL MICROCIRCULATION IN SEPTIC SHOCK PATIENTS: A RANDOMIZED CONTROLLED TRIAL

ABSTRACT

Background and Objective: The optimization of macrocirculatory hemodynamics is recommended by current sepsis guidelines. However, microcirculatory dysfunction is considered the cause of severe sepsis. In the present study, we designed to verify whether the application of Shenfu injection (SFI) restores microcirculation, thereby improving tissue perfusion and inhibiting organ dysfunction, resulting in improved outcomes. Design: We conducted a prospective, single-center, randomized, double-blind, placebo-controlled clinical trial. Intervention: Patients were randomly assigned to group receiving SFI (n = 20) or placebo (n = 20) for 5 days. We administered SFI or glucose injection for 5 days and blinded the investigators and clinical staff by applying light-proof infusion equipment that concealed therapy allocation. Measurements and Results: We measured the systemic dynamics and lactate levels, biomarkers of endothelial dysfunction, and inflammatory cytokines in the plasma. The parameters of sublingual microcirculation were assessed using side-stream dark-field imaging. Sequential Organ Failure Assessment (SOFA) score, Acute Physiology and Chronic Health Evaluation (APACHE) score, total dose, and duration of vasopressor use, emergency intensive care unit (EICU) stay, and 28-day mortality were evaluated. After treatment with SFI, the disturbance of the sublingual microcirculation was considerably alleviated, as indicated by the significant increase in total vessel density, perfused vessel density, and microvascular flow index. Moreover, the plasma biomarker levels of endothelial dysfunction, including Ang-2, Syn-1, and ET-1, were reversed after SFI treatment. Importantly, the SFI group had a more favorable prognosis than the control group in terms of the APACHE-II score, SOFA score, duration of vasopressor administration, and length of EICU stay. However, the difference in mortality at day 28 was not statistically different between the SFI (15%, 3/20) and placebo (25%, 5/20) groups ( P = 0.693). Conclusions : Shenfu injection provided apparent effects in improving sublingual microcirculatory perfusion in patients with septic shock, and this protection may be related with the inhibition of endothelial dysfunction and vasodilatory effects.

[Hemodynamic Monitoring in the ICU: the More Invasive, the Better?]

Less invasive or even completely non-invasive haemodynamic monitoring technologies have evolved during the last decades. However, the invasive devices such as the pulmonary artery catheter and transpulmonary thermodilution technologies are still the clinical gold standard in terms of advanced haemodynamic monitoring, especially in the treatment of critically ill patients. The current data situation regarding the early use of continuous haemodynamic monitoring in this patient population, specifically flow-based variables such as stroke volume to prevent occult hypoperfusion, is overwhelming. However, the effective implementation of these technologies in daily clinical routine is remarkably low. Given the fact that perioperative morbidity and mortality are higher than anticipated, anaesthesiologists and intensivists are in charge to deal with this problem. The recent advances in minimally invasive and non-invasive haemodynamic monitoring technologies may facilitate a more widespread use in the operating theatre and in critical care patients. This review evaluates the significance of invasive, minimally- and non-invasive monitoring devices and their specific haemodynamic variables in this particular field of perioperative medicine.

Pathophysiology, mechanisms, and managements of tissue hypoxia

Oxygen is needed to generate aerobic adenosine triphosphate and energy that is required to support vital cellular functions. Oxygen delivery (DO₂) to the tissues is determined by convective and diffusive processes. The ability of the body to adjust oxygen extraction (ERO₂) in response to changes in DO₂ is crucial to maintain constant tissue oxygen consumption (VO₂). The capability to increase ERO₂ is the result of the regulation of the circulation and the effects of the simultaneous activation of both central and local factors. The endothelium plays a crucial role in matching tissue oxygen supply to demand in situations of acute drop in tissue oxygenation. Tissue oxygenation is adequate when tissue oxygen demand is met. When DO₂ is severely compromised, a critical DO₂ value is reached below which VO₂ falls and becomes dependent on DO₂, resulting in tissue hypoxia. The different mechanisms of tissue hypoxia are circulatory, anaemic, and hypoxic, characterised by a diminished DO₂ but preserved capacity of increasing ERO₂. Cytopathic hypoxia is another mechanism of tissue hypoxia that is due to impairment in mitochondrial respiration that can be observed in septic conditions with normal overall DO₂. Sepsis induces microcirculatory alterations with decreased functional capillary density, increased number of stopped-flow capillaries, and marked heterogeneity between the areas with large intercapillary distance, resulting in impairment of the tissue to extract oxygen and to satisfy the increased tissue oxygen demand, leading to the development of tissue hypoxia. Different therapeutic approaches exist to increase DO₂ and improve microcirculation, such as fluid therapy, transfusion, vasopressors, inotropes, and vasodilators. However, the effects of these agents on microcirculation are quite variable.

Cerebral Oximetry-Monitored Nitroglycerin Infusion and Tissue Perfusion during Rewarming of Cardiopulmonary Bypass in Cardiac Surgery: A Prospective Randomized Trial

Background: Nitroglycerin facilitates microcirculation and oxygen delivery through vasodilation. The purpose of this study was to clarify the effects of nitroglycerin-induced vasodilation and potential hypotension on tissue perfusion under cerebral oximetry monitoring during rewarming in cardiopulmonary bypass. Methods: Elective cardiac surgical patients were randomly assigned to either a nitroglycerin group (n = 32) with an intravenous infusion of 1–5 mcg/kg/min or a control group (n = 31) with 0–0.1 mcg/kg/min infusion, since the initiation of rewarming. Perioperative arterial blood gas data were collected in addition to hemodynamic variables, cerebral oximetry values, urine output, and postoperative outcomes. Results: Nearly one-fifth (6/32) of patients in the nitroglycerin group experienced transient (≤5 min) profound hypotension (mean arterial blood pressure ≤40 mmHg) after the initiation of infusion. There were no significant differences between groups in terms of perioperative levels of cerebral oximetry, cardiac index, plasma glucose, lactate, bicarbonate, base excess, or post-bypass activated coagulation time. In the nitroglycerin group, urine output was nonsignificantly higher during cardiopulmonary bypass (p = 0.099) and within 8 h after surgery (p = 0.157). Perioperative transfused blood products, postoperative inotropic doses, extubation time, and intensive care unit stay were comparable for the two groups. Conclusions: Initiation of intravenous nitroglycerin infusion (at 1–5 mcg/kg/min) during rewarming in hypothermic cardiopulmonary bypass resulted in transient profound hypotension in one-fifth of patients and did not improve perioperative cerebral oxygenation, tissue perfusion, and coagulation in cardiac surgery.

Clinical use of peripheral perfusion parameters in septic shock

PURPOSE OF REVIEW

Current goals of resuscitation in septic shock are mainly a fixed volume of fluids and vasopressors to correct hypotension and improve tissue perfusion indicated by decreasing lactate levels.

RECENT FINDINGS

Abnormal peripheral perfusion by objective and subjective parameters are associated with increased mortality in various phases of the treatment of critically ill patients including patients with septic shock. Ongoing resuscitation in septic shock patients with normal peripheral perfusion is not associated with improved outcome, rather with increased mortality. Mitigation of fluid resuscitation by using parameters of peripheral perfusion in septic shock seems to be safe.

SUMMARY

Septic shock patients with normal peripheral perfusion represent a different clinical phenotype of patients that might benefit from limited resuscitation efforts. Parameters of peripheral perfusion could be used to guide the individualization of patients with septic shock.

Noninvasive Monitoring in the Intensive Care Unit

There has been considerable development in the field of noninvasive hemodynamic monitoring in recent years. Multiple devices have been proposed to assess blood pressure, cardiac output, and tissue perfusion. All have their own advantages and disadvantages and selection should be based on individual patient requirements and disease severity and adjusted according to ongoing patient evolution.

Can Peripheral Skin Perfusion Be Used to Assess Organ Perfusion and Guide Resuscitation Interventions?

Although the definition of septic shock is straightforward, the physiological response to inadequate hemodynamics in patients with septic shock is variable. Therefore, the clinical recognition is limited not only by the patient's response but also by the clinical parameters we can use at the bedside. In this short overview we will argue that the state of the peripheral perfusion can help to identify and to treat patients with septic shock.

Capillary refill time as part of an early warning score for rapid response team activation is an independent predictor of outcomes

BACKGROUND

Capillary refill time (CRT) is easy, quick to perform and when prolonged in critical illness, correlates with progression of organ failure and mortality. It is utilized in our hospital's early warning score (EWS) as one of 11 parameters. We sought to define CRT's value in predicting patient outcomes, compared to the remaining EWS elements.

METHODS

Five-year prospective observational study of 6480 consecutive Rapid Response Team (RRT) patients. CRT measured at the index finger was considered prolonged if time to previous-color return was >3 s. We analyzed the odds ratio of normal vs prolonged-CRT, compared to the other EWS variables, to individual and combined outcomes of mortality, cardiac arrest and higher-level of care transfer.

RESULTS

Twenty-percent (N = 1329) of RRT-patients had prolonged-CRT (vs normal-CRT), were twice as likely to die (36% vs 17.8%, p < .001), more likely to experience the combined outcome (72.1% vs 54.2%, p < .001) and had longer hospital length of stays, 15.3 (SD 0.3) vs 13.5 days (SD 0.5) (p < .001). Multivariable logistic regression for mortality ranked CRT second to hypoxia among all 11 variables evaluated (p < 001).

CONCLUSIONS

This is the first time CRT has been evaluated in RRT patients. Its measurement is easy to perform and proves useful as an assessment of adult patients at-risk for clinical decline. Its prolongation in our population was an independent predictor of mortality and the combined outcome. This study and others suggest that CRT should be considered further as a fundamental assessment of patients at-risk for clinical decline.

Bedside prediction of intradialytic hemodynamic instability in critically ill patients: the SOCRATE study

BACKGROUND

Despite improvements in intermittent hemodialysis management, intradialytic hemodynamic instability (IHI) remains a common issue that could account for increased mortality and delayed renal recovery. However, predictive factors of IHI remain poorly explored. The objective of this study was to evaluate the relationship between baseline macrohemodynamic, tissue hypoperfusion parameters and IHI occurrence.

METHODS

Prospective observational study conducted in a 18-bed medical ICU of a tertiary teaching hospital. Cardiovascular SOFA score, index capillary refill time (CRT) and lactate level were measured just before (T0) consecutive intermittent hemodialysis sessions performed for AKI. The occurrence of IHI requiring a therapeutic intervention was recorded.

RESULTS

Two hundred eleven sessions, corresponding to 72 (34%) first sessions and 139 (66%) later sessions, were included. As IHI mostly occurred during first sessions (43% vs 12%, P < 0.0001), following analyses were performed on the 72 first sessions. At T0, cardiovascular SOFA score ≥1 (87% vs 51%, P = 0.0021) was more frequent before IHI sessions, as well as index CRT ≥ 3 s (55% vs 15%, P = 0.0004), and hyperlactatemia > 2 mmol/L (68% vs 29%, P = 0.0018). Moreover, the occurrence of IHI increased with the number of macrohemodynamic and tissue perfusion impaired parameters, named SOCRATE score (cardiovascular SOFA, index CRT and lactATE): 10% (95% CI [3%, 30%]), 33% (95% CI [15%, 58%]), 55% (95% CI [35%, 73%]) and 80% (95% CI [55%, 93%]) for 0, 1, 2 and 3 parameters, respectively (AUC = 0.79 [0.69-0.89], P < 0.0001). These results were confirmed by analyzing the 139 later sessions included in the study.

CONCLUSIONS

The SOCRATE score based on 3 easy-to-use bedside parameters correlates with the risk of IHI. By improving risk stratification of IHI, this score could help clinicians to manage intermittent hemodialysis initiation in critically ill AKI patients.

Effects of nitroglycerin versus labetalol on peripheral perfusion during deliberate hypotension for sinus endoscopic surgery: a randomized, controlled, double-blinded trial

Background

Deliberate hypotension is used to provide a bloodless field during functional endoscopic sinus surgery; however, the impact of controlled hypotension during anesthesia on peripheral tissue perfusion has not been extensively evaluated. The aim of this study was to compare the impact of nitroglycerin- versus labetalol-induced hypotension on peripheral perfusion.

Methods

The present randomized, double-blinded, controlled trial included adult patients undergoing endoscopic sinus surgery. Patients were allocated to one of two groups according to the drug received for induction of deliberate hypotension: nitroglycerin (n = 20) or labetalol (n = 20). Mean arterial pressure was maintained at 55–65 mmHg in both groups. Both study groups were compared according to pulse oximeter-derived peripheral perfusion index (primary outcome), serum lactate level, mean arterial pressure, heart rate, surgical field score, and intraoperative blood loss.

Results

Forty patients were included in the final analysis. The nitroglycerin group exhibited a higher peripheral perfusion index at nearly all records (p < 0.0001) and lower postoperative serum lactate levels (1.3 ± 0.2 mmol/L vs. 1.7 ± 0.4 mmol/L; p = 0.001) than the labetalol group. The peripheral perfusion index was higher in the nitroglycerin group than at baseline at most intraoperative readings. The median surgical field score was modestly lower in the labetalol group than in the nitroglycerin group in the first 20 min (2 [interquartile range (IQR) 2–2.5] versus 1.5 [IQR 1–2]; p = 0.001). Both groups demonstrated comparable and acceptable surgical field scores in all subsequent readings.

Conclusion

Nitroglycerin-induced deliberate hypotension was accompanied by higher peripheral perfusion index and lower serum lactate levels than labetalol-induced deliberate hypotension during sinus endoscopic surgery.

Trial registration

The study was registered at clinicaltrials registry system with trial number: NCT03809065. Registered at 19 January 2019. This study adheres to CONSORT guidelines.

High-dose nitroglycerin administered during rewarming preserves erythrocyte deformability in cardiac surgery with cardiopulmonary bypass

OBJECTIVE

We aimed to determine whether high-dose nitroglycerin, a nitric oxide donor, preserves erythrocyte deformability during cardiopulmonary bypass and examines the signaling pathway of nitric oxide in erythrocytes.

METHODS

In a randomized and controlled fashion, forty-two patients undergoing cardiac surgery with hypothermic cardiopulmonary bypass were allocated to high-dose (N = 21) and low-dose groups (N = 21). During rewarming period, patients were given intravenous nitroglycerin with an infusion rate 5 and 1 µg·kg^-1 ·min^-1 in high-dose and low-dose groups, respectively. Tyrosine phosphorylation level of non-muscle myosin IIA in erythrocyte membrane was used as an index of erythrocyte deformability and analyzed using immunoblotting.

RESULTS

Tyrosine phosphorylation of non-muscle myosin IIA was significantly enhanced after bypass in high-dose group (3.729 ± 1.700 folds, P = .011) but not low-dose group (1.545 ± 0.595 folds, P = .076). Phosphorylation of aquaporin 1, vasodilator-stimulated phosphoprotein, and focal adhesion kinase in erythrocyte membrane was also upregulated in high-dose group after bypass. Besides, plasma nitric oxide level was highly correlated with fold change of non-muscle myosin IIA phosphorylation (Pearson's correlation coefficient .871).

CONCLUSIONS

High-dose nitroglycerin administered during cardiopulmonary bypass improves erythrocyte deformability through activating phosphorylation of aquaporin 1, vasodilator-stimulated phosphoprotein, and focal adhesion kinase in erythrocytes.

From a pressure-guided to a perfusion-centered resuscitation strategy in septic shock: Critical literature review and illustrative case

PURPOSE

To support a paradigm shift in the management of septic shock from pressure-guided to perfusion-centered, expected to improve outcome while reducing adverse effects from vasopressor therapy and aggressive fluid resuscitation.

MATERIAL AND METHODS

Critical review of the literature cited in support of vasopressor use to achieve a predefined mean arterial pressure (MAP) of 65 mmHg and review of pertinent clinical trials and studies enabling deeper understanding of the hemodynamic pathophysiology supportive of a perfusion-centered approach, accompanied by an illustrative case.

RESULTS

Review of the literature cited by the Surviving Sepsis Campaign revealed lack of controlled clinical trials supporting outcome benefits from vasopressors. Additional literature review revealed adverse effects associated with vasopressors and worsened outcome in some studies. Vasopressors increase MAP primarily by peripheral vasoconstriction and in occasions by a modest increase in cardiac output when using norepinephrine. Thus, achieving the recommended MAP of 65 mmHg using vasopressors should not be presumed indicative that organ perfusion has been restored. It may instead create a false sense of hemodynamic stability hampering shock resolution.

CONCLUSIONS

We propose focusing the hemodynamic management of septic shock on reversing organ hypoperfusion instead of attaining a predefined MAP target as the key strategy for improving outcome.

Assessment of the peripheral microcirculation in patients with and without shock: a pilot study on different methods

Microvascular dysfunction has been associated with adverse outcomes in critically ill patients, and the current concept of hemodynamic incoherence has gained attention. Our objective was to perform a comprehensive analysis of microcirculatory perfusion parameters and to investigate the best variables that could discriminate patients with and without circulatory shock during early intensive care unit (ICU) admission. This prospective observational study comprised a sample of 40 adult patients with and without circulatory shock (n = 20, each) admitted to the ICU within 24 h. Peripheral clinical [capillary refill time (CRT), peripheral perfusion index (PPI), skin-temperature gradient (Tskin-diff)] and laboratory [arterial lactate and base excess (BE)] perfusion parameters, in addition to near-infrared spectroscopy (NIRS)-derived variables were simultaneously assessed. While lactate, BE, CRT, PPI and Tskin-diff did not differ significantly between the groups, shock patients had lower baseline tissue oxygen saturation (StO₂) [81 (76–83) % vs. 86 (76–90) %, p = 0.044], lower StO₂min [50 (47–57) % vs. 55 (53–65)  %, p = 0.038] and lower StO₂max [87 (80–92) % vs. 93 (90–95) %, p = 0.017] than patients without shock. Additionally, dynamic NIRS variables [recovery time (r = 0.56, p = 0.010), descending slope (r = − 0.44, p = 0.05) and ascending slope (r = − 0.54, p = 0.014)] and not static variable [baseline StO₂ (r = − 0.24, p = 0.28)] exhibited a significant correlation with the administered dose of norepinephrine. In our study with critically ill patients assessed within the first twenty-four hours of ICU admission, among the perfusion parameters, only NIRS-derived parameters could discriminate patients with and without shock.

Narrative review: clinical assessment of peripheral tissue perfusion in septic shock

Sepsis is one of the main reasons for intensive care unit admission and is responsible for high morbidity and mortality. The usual hemodynamic targets for resuscitation of patients with septic shock use macro-hemodynamic parameters (hearth rate, mean arterial pressure, central venous pressure). However, persistent alterations of microcirculatory blood flow despite restoration of macro-hemodynamic parameters can lead to organ failure. This dissociation between macro- and microcirculatory compartments brings a need to assess end organs tissue perfusion in patients with septic shock. Traditional markers of tissue perfusion may not be readily available (lactate) or may take time to assess (urine output). The skin, an easily accessible organ, allows clinicians to quickly evaluate the peripheral tissue perfusion with noninvasive bedside parameters such as the skin temperatures gradient, the capillary refill time, the extent of mottling and the peripheral perfusion index.

Effect of a Resuscitation Strategy Targeting Peripheral Perfusion Status vs Serum Lactate Levels on 28-Day Mortality Among Patients With Septic Shock: The ANDROMEDA-SHOCK Randomized Clinical Trial

IMPORTANCE

Abnormal peripheral perfusion after septic shock resuscitation has been associated with organ dysfunction and mortality. The potential role of the clinical assessment of peripheral perfusion as a target during resuscitation in early septic shock has not been established.

OBJECTIVE

To determine if a peripheral perfusion-targeted resuscitation during early septic shock in adults is more effective than a lactate level-targeted resuscitation for reducing mortality.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, randomized trial conducted at 28 intensive care units in 5 countries. Four-hundred twenty-four patients with septic shock were included between March 2017 and March 2018. The last date of follow-up was June 12, 2018.

INTERVENTIONS

Patients were randomized to a step-by-step resuscitation protocol aimed at either normalizing capillary refill time (n = 212) or normalizing or decreasing lactate levels at rates greater than 20% per 2 hours (n = 212), during an 8-hour intervention period.

MAIN OUTCOMES AND MEASURES

The primary outcome was all-cause mortality at 28 days. Secondary outcomes were organ dysfunction at 72 hours after randomization, as assessed by Sequential Organ Failure Assessment (SOFA) score (range, 0 [best] to 24 [worst]); death within 90 days; mechanical ventilation-, renal replacement therapy-, and vasopressor-free days within 28 days; intensive care unit and hospital length of stay.

RESULTS

Among 424 patients randomized (mean age, 63 years; 226 [53%] women), 416 (98%) completed the trial. By day 28, 74 patients (34.9%) in the peripheral perfusion group and 92 patients (43.4%) in the lactate group had died (hazard ratio, 0.75 [95% CI, 0.55 to 1.02]; P = .06; risk difference, -8.5% [95% CI, -18.2% to 1.2%]). Peripheral perfusion-targeted resuscitation was associated with less organ dysfunction at 72 hours (mean SOFA score, 5.6 [SD, 4.3] vs 6.6 [SD, 4.7]; mean difference, -1.00 [95% CI, -1.97 to -0.02]; P = .045). There were no significant differences in the other 6 secondary outcomes. No protocol-related serious adverse reactions were confirmed.

CONCLUSIONS AND RELEVANCE

Among patients with septic shock, a resuscitation strategy targeting normalization of capillary refill time, compared with a strategy targeting serum lactate levels, did not reduce all-cause 28-day mortality.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03078712.

Exploration de la perfusion tissulaire microcirculatoire au cours du choc septique

Au cours des infections graves, les travaux chez l’animal et chez l’homme ont mis en évidence une altération de la perfusion microcirculatoire à l’origine des défaillances viscérales et potentiellement du décès. La sévérité des anomalies microcirculatoires ainsi que leur persistance sont des facteurs prédictifs de mortalité indépendamment du débit cardiaque ou de la pression artérielle. Il est donc indispensable de développer des outils permettant d’évaluer la perfusion microcirculatoire au lit du malade. De nombreux travaux au cours du sepsis suggèrent que l’analyse de la perfusion cutanée au travers de sa température (et/ou du gradient), du temps de recoloration cutané, de l’étendue des marbrures et de l’indice de perfusion périphérique constitue un outil simple qui permet au réanimateur une évaluation rapide des anomalies microcirculatoires.

Vasodilators in Septic Shock Resuscitation: A Clinical Perspective

Microcirculatory abnormalities have been shown to be frequent in patients with septic shock despite "normalization" of systemic hemodynamics. Several studies have explored the impact of vasodilator therapy (prostacyclin, inhaled nitric oxide, topic acetylcholine, and nitroglycerin) on microcirculation and tissue perfusion, with contradictory findings.In this narrative review, we briefly present the pathophysiological aspects of microcirculatory dysfunction, and depict the evidence supporting the use of vasodilators and other therapeutic interventions (fluid administration, blood transfusion, vasopressors, and dobutamine) aiming to improve the microcirculatory flow in septic shock patients.

Hemodynamic coherence in critically ill pediatric patients

Differences in physiology and pathophysiology make the treatment of developing, critically ill children particularly challenging as compared to that of adults. Significant differences in the cardiovascular system of neonates and children in size, weight, body proportions, and metabolism should be considered. Hemodynamic monitoring is crucial for early warning of pending deterioration and to guide therapy. Current monitoring is limited to the macrocirculation, but an adequately functioning macrocirculation does not guarantee a well-functioning microcirculation. Research in children revealed loss of hemodynamic coherence, i.e., microcirculatory alterations despite normal systemic hemodynamics. Implementing the framework of hemodynamic coherence in microcirculatory monitoring in children can aid physicians in titrating therapy on both macrocirculatory and microcirculatory effects to assure optimal oxygen delivery. Monitoring the microcirculation at the bedside requires further technical development. Although more research is necessary to validate the concept of hemodynamic coherence in children, the possibilities of applying this concept in children seem promising.

Toe-to-room temperature gradient correlates with tissue perfusion and predicts outcome in selected critically ill patients with severe infections

Background

Microcirculatory disorders leading to tissue hypoperfusion play a central role in the pathophysiology of organ failure in severe sepsis and septic shock. As microcirculatory disorders have been identified as strong predictive factors of unfavourable outcome, there is a need to develop accurate parameters at the bedside to evaluate tissue perfusion. We evaluated whether different body temperature gradients could relate to sepsis severity and could predict outcome in critically ill patients with severe sepsis and septic shock.

Method

We conducted a prospective observational study in a tertiary teaching hospital in France. During a 10-month period, all consecutive adult patients with severe sepsis or septic shock who required ICU admission were included. Six hours after initial resuscitation (H6), we recorded the hemodynamic parameters and four temperature gradients: central-to-toe, central-to-knee, toe-to-room and knee-to-room.

Results

We evaluated 40 patients with severe sepsis (40/103, 39 %) and 63 patients with septic shock (63/103, 61 %). In patients with septic shock, central-to-toe temperature gradient was significantly higher (12.5 [9.2; 13.8] vs 6.9 [3.4; 12.0] °C, P < 0.001) and toe-to-room temperature gradient significantly lower (1.2 [−0.3; 5.2] vs 6.0 [0.6; 9.5] °C, P < 0.001) than in patients with severe sepsis. Overall ICU mortality rate due to multiple organ failure (MOF) was 21 %. After initial resuscitation, toe-to-room temperature gradient was significantly lower in patients dead from MOF than in the survivors (−0.2 [−1.1; +1.3] °C vs +3.9 [+0.5; +7.2] °C, P < 0.001) and the difference in gradients increased during the first 24 h. Furthermore, toe-to-room temperature gradient was related to tissue perfusion parameters such as arterial lactate level (r = −0.54, P < 0.0001), urine output (r = 0.37, P = 0.0002), knee capillary refill time (r = −0.42, P < 0.0001) and mottling score (P = 0.001).

Conclusions

Toe-to-room temperature gradient reflects tissue perfusion at the bedside and is a strong prognosis factor in critically ill patients with severe infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-016-0164-2) contains supplementary material, which is available to authorized users.

Ultrasound-guided bilateral stellate ganglion blockade to treat digital ischemia in a patient with sepsis: a case report

PURPOSE

This case report describes the use of ultrasound-guided stellate ganglion blockade to treat sepsis-related digital ischemia in the intensive care unit (ICU).

CLINICAL FEATURES

A 71-yr-old female was admitted to the ICU with septic shock and acute respiratory distress syndrome (ARDS) following an initial right hemicolectomy complicated by an anastomotic leak and peritonitis. The patient's condition was further complicated by an abdominal abscess 22 days later. She had type-2 diabetes mellitus and hypertension but no history of vascular disease. With continuing sepsis from the abscess and requiring mechanical ventilation due to ARDS, she developed upper limb digital ischemia refractory to treatment with a low dose of dobutamine and isosorbide dinitrate. We subsequently performed ultrasound-guided bilateral stellate ganglion blockade with the intent of restoring perfusion to her fingers before digital necrosis developed. One hour after each stellate ganglion block, the symptoms of digital ischemia completely resolved. The benefit persisted for two days, and then a repeat block was performed with similar results.

CONCLUSIONS

This case illustrates the potential advantages of ultrasound-guided stellate ganglion blockade for the treatment of sepsis-related digital ischemia refractory to standard therapy.

Clinical classification of tissue perfusion based on the central venous oxygen saturation and the peripheral perfusion index

Introduction

We investigated whether combining the peripheral perfusion index (PI) and central venous oxygen saturation(ScvO₂) would identify subsets of patients for assessing the tissue perfusion and predicting outcome during the resuscitation in critically ill patients.

Methods

A total of 202 patients with central venous catheters for resuscitation were enrolled in this prospective observational study. The arterial, central venous blood gas and the PI were measured simultaneously at the enrollment (T0) and 8 h (T8) after early resuscitation. Based on the distribution of the PI in healthy population, a cutoff of PI ≥1.4 was defined as a normal PI. Moreover, the critical value of PI was defined as the best cutoff value related to the mortality in the study population. The PI impairment stratification is defined as follows: a normal PI(≥1.4), mild PI impairment (critical value < PI < 1.4) and critical PI impairment (PI ≤ critical value).

Results

The PI at T8 was with the greatest AUC for prediction the 30-day mortality and PI is an independent risk factor for 30-day mortality. Moreover, a cutoff of PI < 0.6 is related to poor outcomes following resuscitation. So, based on cutoffs of ScvO₂ (70 %) and critical PI (0.6) at T8, we assigned the patients to four categories: group 1 (PI ≤ 0.6 on ScvO₂ < 70 %), group 2 (PI ≤ 0.6 on ScvO₂ ≥ 70 %), group 3 (PI > 0.6 on ScvO₂ < 70 %), and group 4 (PI > 0.6 on ScvO₂ ≥ 70 %). The combination of low ScvO₂(<70 %) and PI(≤0.6) was associated with the lowest survival rates at 30 days [log rank (Mantel–Cox) = 87.518, p < 0.0001]. The sub-group patients who had high ScvO₂(>80 %) at T8 were with low mortality and high PI. Moreover, the normal PI (≥1.4) did not show a better outcome than mild impaired PI (0.6-1.4) patients who had a normalized ScvO₂(>70 %) after resuscitation. The PI was correlated with the lactate, P(v-a)CO₂, and ScvO₂ in all the measurements (n = 404). These relationships are strengthened with abnormal PI (PI < 1.4) but not with normal PI (PI ≥ 1.4).

Conclusion

Complementing ScvO₂ assessment with PI can better identify endpoints of resuscitation and adverse outcomes. Pursuing a normalized PI (≥1.4) may not result in better outcomes for a mild impaired PI after ScvO₂ is normalized.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1057-8) contains supplementary material, which is available to authorized users.

Assessment of Fluid Balance and the Approach to Fluid Therapy in the Perioperative Patient

Perioperative patients can be highly dynamic and have various metabolic, physiologic, and organ system derangements that necessitate smart monitoring strategies and careful fluid therapy. The interplay between changing patient status, therapeutic interventions, and patient response makes effective monitoring crucial to successful treatment. Monitoring the perioperative patient and an approach to fluid therapy are discussed in this text.

Incidence and impact of skin mottling over the knee and its duration on outcome in critically ill patients

PURPOSE

Skin mottling is frequent and can be associated with an increased mortality rate in ICU patients with septic shock. Its overall incidence in ICU and its impact on outcome is unknown. We aimed to assess the incidence of skin mottling over the knee among all critically ill patients admitted in ICU and its role on their outcome.

METHODS

An observational study over a 1-year period in a 15-bed medical ICU of a teaching hospital. Skin mottling over the knee was prospectively and qualitatively assessed by trained nurses.

RESULTS

Incidence of skin mottling was 29% (230 of 791 patients) in overall, and 49% (32 of 65 patients) in the subset of patients admitted for septic shock. Skin mottling was present on the day on admission in 65% of patients and persisted more than 6 h in 59% of cases. In-ICU mortality was 8% in patients without mottling, 30% in patients with short skin mottling and 40% in patients with persistent skin mottling (p < 0.01 between all groups). In the overall population, skin mottling over the knee was associated with in-ICU mortality independently from SAPS II (aOR 3.29 [95% CI, 2.08-5.19], p < 0.0001). Among patients with skin mottling over the knee, persistence of skin mottling remained associated with increased in-ICU mortality independently of organ dysfunctions at the mottling onset (OR 2.77 [95% CI, 1.34-5.72], p = 0.004).

CONCLUSIONS

Skin mottling is frequent in the general population of patients admitted in ICU. Occurrence and persistence of skin mottling are independently associated with in-ICU mortality.