Alteration of skin perfusion in mottling area during septic shock

Resuscitating the macro- vs. microcirculation in septic shock

PURPOSE OF REVIEW

This review summarizes current literature about the relationships between macro and microcirculation and their practical clinical implications in children with septic shock.

RECENT FINDINGS

Current evidence from experimental and clinical observational studies in children and adults with septic shock reveals that the response to treatment and resuscitation is widely variable. Furthermore, there is a loss of hemodynamic coherence, as resuscitation-induced improvement in macrocirculation (systemic hemodynamic parameters) does not necessarily result in a parallel improvement in the microcirculation. Therefore, patient-tailored monitoring is essential in order to adjust treatment requirements during resuscitation in septic shock. Optimal monitoring must integrate macrocirculation (heart rate, blood pressure, cardiac output, and ultrasound images), microcirculation (videomicroscopy parameters and capillary refill time) and cellular metabolism (lactic acid, central venous blood oxygen saturation, and difference of central venous to arterial carbon dioxide partial pressure).

SUMMARY

There is a dire need for high-quality studies to assess the relationships between macrocirculation, microcirculation and tissue metabolism in children with septic shock. The development of reliable and readily available microcirculation and tissue perfusion biomarkers (other than lactic acid) is also necessary to improve monitoring and treatment adjustment in such patients.

Skin mottling score assesses peripheral tissue hypoperfusion in critically ill patients following cardiac surgery

BACKGROUND

Skin mottling is a common manifestation of peripheral tissue hypoperfusion, and its severity can be described using the skin mottling score (SMS). This study aims to evaluate the value of the SMS in detecting peripheral tissue hypoperfusion in critically ill patients following cardiac surgery.

METHODS

Critically ill patients following cardiac surgery with risk factors for tissue hypoperfusion were enrolled (n = 373). Among these overall patients, we further defined a hypotension population (n = 178) and a shock population (n = 51). Hemodynamic and perfusion parameters were recorded. The primary outcome was peripheral hypoperfusion, defined as significant prolonged capillary refill time (CRT, > 3.0 s). The characteristics and hospital mortality of patients with and without skin mottling were compared. The area under receiver operating characteristic curves (AUROC) were used to assess the accuracy of SMS in detecting peripheral hypoperfusion. Besides, the relationships between SMS and conventional hemodynamic and perfusion parameters were investigated, and the factors most associated with the presence of skin mottling were identified.

RESULTS

Of the 373-case overall population, 13 (3.5%) patients exhibited skin mottling, with SMS ranging from 1 to 5 (5, 1, 2, 2, and 3 cases, respectively). Patients with mottling had lower mean arterial pressure, higher vasopressor dose, less urine output (UO), higher CRT, lactate levels and hospital mortality (84.6% vs. 12.2%, p < 0.001). The occurrences of skin mottling were higher in hypotension population and shock population, reaching 5.6% and 15.7%, respectively. The AUROC for SMS to identify peripheral hypoperfusion was 0.64, 0.68, and 0.81 in the overall, hypotension, and shock populations, respectively. The optimal SMS threshold was 1, which corresponded to specificities of 98, 97 and 91 and sensitivities of 29, 38 and 67 in the three populations (overall, hypotension and shock). The correlation of UO, lactate, CRT and vasopressor dose with SMS was significant, among them, UO and CRT were identified as two major factors associated with the presence of skin mottling.

CONCLUSION

In critically ill patients following cardiac surgery, SMS is a very specific yet less sensitive parameter for detecting peripheral tissue hypoperfusion.

Capillary refill time assessment after fluid challenge in patients on venoarterial extracorporeal membrane oxygenation: A retrospective study

BACKGROUND

Monitoring fluid therapy is challenging in patients assisted with Veno-arterial ECMO. The aim of our study was to evaluate the usefulness of capillary refill time to assess the response to fluid challenge in patients assisted with VA-ECMO.

METHODS

Retrospective monocentric study in a cardiac surgery ICU. We assess fluid responsiveness after a fluid challenge in patients on VA-ECMO. We recorded capillary refill time before and after fluid challenge and the evolution of global hemodynamic parameters.

RESULTS

A total of 27 patients were included. The main indications for VA-ECMO were post-cardiotomy cardiogenic shock (44%). Thirteen patients (42%) were responders and 14 non-responders (58%). In the responder group, the index CRT decreased significantly (1.7 [1.5; 2.1] vs. 1.2 [1; 1.3] s; p = 0.01), whereas it remained stable in the non-responder group (1.4 [1.1; 2.5] vs. 1.6 [0.9; 1.9] s; p = 0.22). Diagnosis performance of CRT variation to assess response after fluid challenge shows an AUC of 0.68 (p = 0.10) with a sensitivity of 79% [95% CI, 52-92] and a specificity of 69% [95% CI, 42-87], with a threshold at 23%.

CONCLUSION

In patients treated with VA-ECMO index capillary refill time is a reliable tool to assesses fluid responsiveness.

SPECIALTY

Critical care, Cardiac surgery, ECMO.

Skin Mottling in Dark-skinned Indian Patients with Severe Septic Shock: A Window to the Circulation or a Closed Door?

Skin mottling has been found to be useful as a marker of peripheral hypoperfusion in shock in studies performed on fair-skinned patients. Whether skin mottling may be less apparent in dark-skinned patients, thus limiting its value in this patient population has not been studied. Jog et al. have performed an elegant study addressing this question, which is important and especially relevant to the Indian situation. They found that mottling is not easily visible in dark-skinned Indian patients, and when it becomes apparent, it is associated with a very high mortality. This study also throws up some areas for future research, including interobserver variability in the detection of mottling, and the hemodynamic and microcirculatory parameters associated with the appearance of mottling. Based on this study, the utility of skin mottling as a tool to guide hemodynamic management in severe septic shock in dark-skinned Indian patients is questionable.

How to cite this article

Divatia JV. Skin Mottling in Dark-skinned Indian Patients with Severe Septic Shock: A Window to the Circulation or a Closed Door? Indian J Crit Care Med 2024;28(1):18-19.

Mottling as a prognosis marker in cardiogenic shock

AIMS

Impact of skin mottling has been poorly studied in patients admitted for cardiogenic shock. This study aimed to address this issue and identify determinants of 30-day and 1-year mortality in a large cardiogenic shock cohort of all etiologies.

METHODS AND RESULTS

FRENSHOCK is a prospective multicenter observational registry conducted in French critical care units between April and October, 2016. Among the 772 enrolled patients (mean age 65.7 ± 14.9 years; 71.5% male), 660 had skin mottling assessed at admission (85.5%) with almost 39% of patients in cardiogenic shock presenting mottling. The need for invasive respiratory support was significantly higher in patients with mottling (50.2% vs. 30.1%, p < 0.001) and likewise for the need for renal replacement therapy (19.9% vs. 12.4%, p = 0.09). However, the need for mechanical circulatory support was similar in both groups. Patients with mottling at admission presented a higher length of stay (19 vs. 16 days, p = 0.033), a higher 30-day mortality rate (31% vs. 23.3%, p = 0.031), and also showed significantly higher mortality at 1-year (54% vs. 42%, p = 0.003). The subgroup of patients in whom mottling appeared during the first 24 h after admission had the worst prognosis at 30 days.

CONCLUSION

Skin mottling at admission in patients with cardiogenic shock was statistically associated with prolonged length of stay and poor outcomes. As a perfusion-targeted resuscitation parameter, mottling is a simple, clinical-based approach and may thus help to improve and guide immediate goal-directed therapy to improve cardiogenic shock patients' outcomes.

Extended prone positioning for intubated ARDS: a review

During the COVID-19 pandemic, several centers had independently reported extending prone positioning beyond 24 h. Most of these centers reported maintaining patients in prone position until significant clinical improvement was achieved. One center reported extending prone positioning for organizational reasons relying on a predetermined fixed duration. A recent study argued that a clinically driven extension of prone positioning beyond 24 h could be associated with reduced mortality. On a patient level, the main benefit of extending prone positioning beyond 24 h is to maintain a more homogenous distribution of the gas-tissue ratio, thus delaying the increase in overdistention observed when patients are returned to the supine position. On an organizational level, extending prone positioning reduces the workload for both doctors and nurses, which might significantly enhance the quality of care in an epidemic. It might also reduce the incidence of accidental catheter and tracheal tube removal, thereby convincing intensive care units with low incidence of ARDS to prone patients more systematically. The main risk associated with extended prone positioning is an increased incidence of pressure injuries. Up until now, retrospective studies are reassuring, but prospective evaluation is needed.

Infrared Thermography Imaging for Assessment of Peripheral Perfusion in Patients with Septic Shock

Skin temperature changes can be used to assess peripheral perfusion in circulatory shock patients. However, research has been limited to point measurements from acral parts of the body. Infrared thermography allows non-invasive evaluation of temperature distribution over a larger surface. Our study aimed to map thermographic patterns in the knee and upper thigh of 81 septic shock patients within 24 h of admission and determine the relationship between skin temperature patterns, mottling, and 28-day mortality. We extracted skin temperature measurements from zones corresponding to mottling scores and used a linear mixed model to analyze the distribution of skin temperature in patients with different mottling scores. Our results showed that the distribution of skin temperature in the anterior thigh and knee is physiologically heterogeneous and has no significant association with mottling or survival at 28 days. However, overall skin temperature of the anterior thigh and knee is significantly lower in non-survivors when modified by mottling score. No differences were found in skin temperature between the survivor and non-survivor groups. Our study shows the potential usefulness of infrared thermography in evaluating skin temperature patterns in resuscitated septic shock patients. Overall skin temperature of the anterior thigh and knee may be an important indicator of survival status when modified by mottling score.

Novelties in the evaluation of microcirculation in septic shock

Microvascular alterations were first described in critically ill patients about 20 years ago. These alterations are characterized by a decrease in vascular density and presence of non-perfused capillaries close to well-perfused vessels. In addition, heterogeneity in microvascular perfusion is a key finding in sepsis. In this narrative review, we report our actual understanding of microvascular alterations, their role in the development of organ dysfunction, and the implications for outcome. Herein, we discuss the state of the potential therapeutic interventions and the potential impact of novel therapies. We also discuss how recent technologic development may affect the evaluation of microvascular perfusion.

Extended prone positioning duration for COVID-19-related ARDS: benefits and detriments

Background

During the COVID-19 pandemic, many more patients were turned prone than before, resulting in a considerable increase in workload. Whether extending duration of prone position may be beneficial has received little attention. We report here benefits and detriments of a strategy of extended prone positioning duration for COVID-19-related acute respiratory distress syndrome (ARDS).

Methods

A eetrospective, monocentric, study was performed on intensive care unit patients with COVID-19-related ARDS who required tracheal intubation and who have been treated with at least one session of prone position of duration greater or equal to 24 h. When prone positioning sessions were initiated, patients were kept prone for a period that covered two nights. Data regarding the incidence of pressure injury and ventilation parameters were collected retrospectively on medical and nurse files of charts. The primary outcome was the occurrence of pressure injury of stage ≥ II during the ICU stay.

Results

For the 81 patients included, the median duration of prone positioning sessions was 39 h [interquartile range (IQR) 34–42]. The cumulated incidence of stage ≥ II pressure injuries was 26% [95% CI 17–37] and 2.5% [95% CI 0.3–8.8] for stages III/IV pressure injuries. Patients were submitted to a median of 2 sessions [IQR 1–4] and for 213 (94%) prone positioning sessions, patients were turned over to supine position during daytime, i.e., between 9 AM and 6 PM. This increased duration was associated with additional increase in oxygenation after 16 h with the PaO₂/FiO₂ ratio increasing from 150 mmHg [IQR 121–196] at H+ 16 to 162 mmHg [IQR 124–221] before being turned back to supine (p = 0.017).

Conclusion

In patients with extended duration of prone position up to 39 h, cumulative incidence for stage ≥ II pressure injuries was 26%, with 25%, 2.5%, and 0% for stage II, III, and IV, respectively. Oxygenation continued to increase significantly beyond the standard 16-h duration. Our results may have significant impact on intensive care unit staffing and patients’ respiratory conditions.

Trial registration: Institutional review board 00006477 of HUPNVS, Université Paris Cité, APHP, with the reference: CER-2021-102, obtained on October 11th 2021. Registered at Clinicaltrials (NCT05124197).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04081-2.

Peripheral tissue hypoperfusion predicts post intubation hemodynamic instability

Background

Tracheal intubation and invasive mechanical ventilation initiation is a procedure at high risk for arterial hypotension in intensive care unit. However, little is known about the relationship between pre-existing peripheral microvascular alteration and post-intubation hemodynamic instability (PIHI).

Methods

Prospective observational monocenter study conducted in an 18-bed medical ICU. Consecutive patients requiring tracheal intubation were eligible for the study. Global hemodynamic parameters (blood pressure, heart rate, cardiac function) and tissue perfusion parameters (arterial lactate, mottling score, capillary refill time [CRT], toe-to-room gradient temperature) were recorded before, 5 min and 2 h after tracheal intubation (TI). Post intubation hemodynamic instability (PIHI) was defined as any hemodynamic event requiring therapeutic intervention.

Results

During 1 year, 120 patients were included, mainly male (59%) with a median age of 68 [57–77]. The median SOFA score and SAPS II were 6 [4–9] and 47 [37–63], respectively. The main indications for tracheal intubation were hypoxemia (51%), hypercapnia (13%), and coma (29%). In addition, 48% of patients had sepsis and 16% septic shock. Fifty-one (42%) patients develop PIHI. Univariate analysis identified several baseline factors associated with PIHI, including norepinephrine prior to TI, sepsis, tachycardia, fever, higher SOFA and high SAPSII score, mottling score ≥ 3, high lactate level and prolonged knee CRT. By contrast, mean arterial pressure, baseline cardiac index, and ejection fraction were not different between PIHI and No-PIHI groups. After adjustment on potential confounders, the mottling score was associated with a higher risk for PIHI (adjusted OR: 1.84 [1.21–2.82] per 1 point increased; p = 0.005). Among both global haemodynamics and tissue perfusion parameters, baseline mottling score was the best predictor of PIHI (AUC: 0.72 (CI 95% [0.62–0.81]).

Conclusions

In non-selected critically ill patients requiring invasive mechanical ventilation, tissue hypoperfusion parameters, especially the mottling score, could be helpful to predict PIHI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01043-3.

Endothelial Activation and Microcirculatory Disorders in Sepsis

The vascular endothelium is crucial for the maintenance of vascular homeostasis. Moreover, in sepsis, endothelial cells can acquire new properties and actively participate in the host's response. If endothelial activation is mostly necessary and efficient in eliminating a pathogen, an exaggerated and maladaptive reaction leads to severe microcirculatory damage. The microcirculatory disorders in sepsis are well known to be associated with poor outcome. Better recognition of microcirculatory alteration is therefore essential to identify patients with the worse outcomes and to guide therapeutic interventions. In this review, we will discuss the main features of endothelial activation and dysfunction in sepsis, its assessment at the bedside, and the main advances in microcirculatory resuscitation.

Vitamin C improves microvascular reactivity and peripheral tissue perfusion in septic shock patients

Background

Vitamin C has potential protective effects through antioxidant and anti-inflammatory properties. However, the effect of vitamin C supplementation on microvascular function and peripheral tissue perfusion in human sepsis remains unknown. We aimed to determine vitamin C effect on microvascular endothelial dysfunction and peripheral tissue perfusion in septic shock patients.

Methods

Patients with septic shock were prospectively included after initial resuscitation. Bedside peripheral tissue perfusion and skin microvascular reactivity in response to acetylcholine iontophoresis in the forearm area were measured before and 1 h after intravenous vitamin C supplementation (40 mg/kg). Norepinephrine dose was not modified during the studied period.

Results

We included 30 patients with septic shock. SOFA score was 11 [8–14], SAPS II was 66 [54–79], and in-hospital mortality was 33%. Half of these patients had vitamin C deficiency at inclusion. Vitamin C supplementation strongly improved microvascular reactivity (AUC 2263 [430–4246] vs 5362 [1744–10585] UI, p = 0.0004). In addition, vitamin C supplementation improved mottling score (p = 0.06), finger-tip (p = 0.0003) and knee capillary refill time (3.7 [2.6–5.5] vs 2.9 [1.9–4.7] s, p < 0.0001), as well as and central-to-periphery temperature gradient (6.1 [4.9–7.4] vs 4.6 [3.4–7.0] °C, p < 0.0001). The beneficial effects of vitamin C were observed both in patients with or without vitamin C deficiency.

Conclusion

In septic shock patients being resuscitated, vitamin C supplementation improved peripheral tissue perfusion and microvascular reactivity whatever plasma levels of vitamin C.

ClinicalTrials.gov Identifier: NCT04778605 registered 26 January 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03891-8.

Septic shock: a microcirculation disease

PURPOSE OF REVIEW

The aim of this study was to discuss the implication of microvascular dysfunction in septic shock.

RECENT FINDINGS

Resuscitation of sepsis has focused on systemic haemodynamics and, more recently, on peripheral perfusion indices. However, central microvascular perfusion is altered in sepsis and these alterations often persist despite normalization of various macro haemodynamic resuscitative goals. Endothelial dysfunction is a key element in sepsis pathophysiology. It is responsible for the sepsis-induced hypotension. In addition, endothelial dysfunction is also implicated involved in the activation of inflammation and coagulation processes leading to amplification of the septic response and development of organ dysfunction. It also promotes an increase in permeability, mostly at venular side, and impairs microvascular perfusion and hence tissue oxygenation.Microvascular alterations are characterized by heterogeneity in blood flow distribution, with adequately perfused areas in close vicinity to not perfused areas, thus characterizing the distributive nature of septic shock. Such microvascular alterations have profound implications, as these are associated with organ dysfunction and unfavourable outcomes. Also, the response to therapy is highly variable and cannot be predicted by systemic hemodynamic assessment and hence cannot be detected by classical haemodynamic tools.

SUMMARY

Microcirculation is a key element in the pathophysiology of sepsis. Even if microcirculation-targeted therapy is not yet ready for the prime time, understanding the processes implicated in microvascular dysfunction is important to prevent chasing systemic hemodynamic variables when this does not contribute to improve tissue perfusion.

Macrocirculatory and Microcirculatory Endpoints in Sepsis Resuscitation

Sepsis is a common disease process encountered by physicians. Sepsis can lead to septic shock, which carries a hospital mortality rate in excess of 40%. Although the Surviving Sepsis Guidelines recommend targeting a mean arterial pressure (MAP) of 65 mmHg and normalization of lactate, these endpoints do not necessarily result in tissue perfusion in states of shock. While MAP and lactate are commonly used markers in resuscitation, clinicians may be able to improve their resuscitation by broadening their assessment of the microcirculation, which more adequately reflects tissue perfusion. As such, in order to achieve a successful resuscitation, clinicians must optimize both macrocirculatory (MAP, cardiac output) and microcirculatory (proportion of perfused vessels, lactate, mottling, capillary refill time) endpoints. This review will summarize various macrocirculatory and microcirculatory markers of perfusion that can be used to guide the initial resuscitation of patients with sepsis.

Assessment of sublingual microcirculation in critically ill patients: consensus and debate

The main concern in shock and resuscitation is whether the microcirculation can carry adequate oxygen to the tissues and remove waste. Identification of an intact coherence between macro- and microcirculation during states of shock and resuscitation shows a functioning regulatory mechanism. However, loss of hemodynamic coherence between the macro and microcirculation can be encountered frequently in sepsis, cardiogenic shock, or any hemodynamically compromised patient. This loss of hemodynamic coherence results in an improvement in macrohemodynamic parameters following resuscitation without a parallel improvement in microcirculation resulting in tissue hypoxia and tissue compromise. Hand-held vital microscopes (HVMs) can visualize the microcirculation and help to diagnose the nature of microcirculatory shock. Although treatment with the sole aim of recruiting the microcirculation is as yet not realized, interventions can be tailored to the needs of the patient while monitoring sublingual microcirculation. With the help of the newly introduced software, called MicroTools, we believe sublingual microcirculation monitoring and diagnosis will be an essential point-of-care tool in managing shock patients.

Effects of very early start of norepinephrine in patients with septic shock: a propensity score-based analysis

BACKGROUND

Optimal timing for the start of vasopressors (VP) in septic shock has not been widely studied since it is assumed that fluids must be administered in advance. We sought to evaluate whether a very early start of VP, even without completing the initial fluid loading, might impact clinical outcomes in septic shock.

METHODS

A total of 337 patients with sepsis requiring VP support for at least 6 h were initially selected from a prospectively collected database in a 90-bed mixed-ICU during a 24-month period. They were classified into very-early (VE-VPs) or delayed vasopressor start (D-VPs) categories according to whether norepinephrine was initiated or not within/before the next hour of the first resuscitative fluid load. Then, VE-VPs (n = 93) patients were 1:1 propensity matched to D-VPs (n = 93) based on age; source of admission (emergency room, general wards, intensive care unit); chronic and acute comorbidities; and lactate, heart rate, systolic, and diastolic pressure at vasopressor start. A risk-adjusted Cox proportional hazard model was fitted to assess the association between VE-VPs and day 28 mortality. Finally, a sensitivity analysis was performed also including those patients requiring VP support for less than 6 h.

RESULTS

Patients subjected to VE-VPs received significantly less resuscitation fluids at vasopressor starting (0[0-510] vs. 1500[650-2300] mL, p < 0.001) and during the first 8 h of resuscitation (1100[500-1900] vs. 2600[1600-3800] mL, p < 0.001), with no significant increase in acute renal failure and/or renal replacement therapy requirements. VE-VPs was related with significant lower net fluid balances 8 and 24 h after VPs. VE-VPs was also associated with a significant reduction in the risk of death compared to D-VPs (HR 0.31, CI95% 0.17-0.57, p < 0.001) at day 28. Such association was maintained after including patients receiving vasopressors for < 6 h.

CONCLUSION

A very early start of vasopressor support seems to be safe, might limit the amount of fluids to resuscitate septic shock, and could lead to better clinical outcomes.

NURSING DIAGNOSIS/OUTCOMES AND INTERVENTIONS FOR CRITICALLY ILL PATIENTS AFFECTED BY COVID-19 AND SEPSIS

ABSTRACT Objective: to relate nursing diagnoses/outcomes and interventions for critically ill patients affected by COVID-19 and sepsis in the Intensive Care Unit, according to the International Classification for Nursing Practice (ICNP®). Method: a documentary study conducted in March and April 2020 from the ICNP® terminology subset for adult patients with sepsis. The documentary corpus was composed of the list of nursing diagnoses/outcomes and interventions based on Horta's Theory of Basic Human Needs; on the 7-Axis Model of the International Classification for Nursing Practice, version 2017; on the Pathophysiological model of sepsis; as well as relying on the authors' expertise in direct care for suspected or confirmed critically ill patients affected by COVID-19. Outcomes: a total of 58 nursing diagnoses/outcomes were identified that belong to the psychobiological needs of oxygenation (13-22.4%), vascular regulation (12-20.7%), neurological regulation (10-17.2%), hydration (08-13.8%), elimination (08-13.8%), immunological regulation (04-6.9%) and thermal regulation (03-5.2%), evidencing a total of 172 nursing interventions with a mean of 03 for each nursing diagnosis/outcome. Conclusion: data analysis provided greater knowledge about the disease and the nursing process in the ICU setting, serving as a guide for the professional practice for critically ill patients hospitalized with COVID-19 and sepsis.

Mottling Incidence and Mottling Score According to Arterial Lactate Level in Septic Shock Patients

Objectives

Mottling score is estimated from 0-5 according to mottling over the knee and described as clinical evaluation of tissue perfusion. This score was developed with ancient definitions of sepsis without lactate level, a major prognostic parameter when superior to 2 mmol/L. This study describes mottling incidence and mottling score in septic shock patients according to lactate level.

Materials and methods

We reanalyzed our prospective study in a French tertiary hospital in the intensive care unit (ICU) which studied mottling score and thermography correlation. Patients admitted to septic shock diagnosis and requiring vasoactive drugs were included. We recorded hemodynamic variables, mottling score, and lactate. Data collection was realized at ICU admission (H0) and after six hours (H6).

Results

Forty-three patients were included. Mean age was 67 (±4), mean sequential organ failure assessment (SOFA) score was 11 (8-12), and SAPS II 58 ±20. Mortality rate at day 28 was 30%. Among patients with lactate ≥2 mmol/L, mottling was more prevalent in 82.6% vs 47.4% (p value = 0.016), and at H6 mottling score was higher (p value = 0.009). Although, mottling incidence was not different between dead (85%) and survivors (81%; p value = 0.795).

Conclusion

A new sepsis definition implies a new epidemiology in mottling according to lactate threshold. Patients with lactate ≥2 mmol/L presented a higher incidence and score of mottling. However, mortality was not influenced by mottling in this study.

Clinical significance

Arterial lactate is a major prognostic parameter when superior to 2 mmol/L.A new definition of sepsis was published in 2016 with a new paradigm and epidemiology of septic shockPatients with lactate ≥2 mmol/L presented a higher incidence and score of mottling.Mottling score is a clinical sign of microcirculatory alteration, related to lactate level in septic shock.

How to cite this article

Ferraris A, Bouisse C, Thiollière F, Piriou V, Allaouchiche B. Mottling Incidence and Mottling Score According to Arterial Lactate Level in Septic Shock Patients. Indian J Crit Care Med 2020;24(8):672-676.

[Causes, diagnosis and treatments of circulatory shocks]

Shock states are the leading causes of intensive care admission and are nowadays associated with high morbidity and mortality. They are driven by a complex physiopathology and most frequently a multifactorial mechanism. They can be separated in whether a decrease of oxygen delivery (quantitative shock) or an abnormal cell distribution of cardiac output (distributive shock). Septic, cardiogenic and hypovolemic shocks represent more than 80% of shock etiologies. Clinical presentation is mostly characterized by frequent arterial hypotension and sign of poor clinical perfusion. Hyperlactatemia occurs in most of shock states. The diagnostic of shock or earlier reversible "pre-shock" states is urgent in order to initiate adequate therapy. Therefore, orientation and therapies must be discussed with intensive care physiologists in a multidisciplinary approach. Etiologic investigation and correction is a primary concern. Hemodynamic and respiratory support reflect another part of initial therapy toward normalization of cell oxygenation. Fluid resuscitation is the corner stone part of initial therapy of any form of shock. Vasoconstrictive drugs or inotropic support still often remain necessary. The primary goal of initial resuscitation should be not only to restore blood arterial pressure but also to improve clinical perfusion markers. On the biological side, decrease of lactate concentration is associated with better outcome.

Relationship of mottling score, skin microcirculatory perfusion indices and biomarkers of endothelial dysfunction in patients with septic shock: an observational study

Background

In patients with septic shock, the skin is often chosen for the evaluation of peripheral perfusion and oxygenation. Changes in skin microcirculatory vessel oxygen saturation and relative hemoglobin concentration can be described using a mottling score or captured with hyperspectral imaging. However, the effectiveness of the mottling score in assessing microcirculation remains to be shown. We hypothesize that the mottling score in patients with septic shock is related to skin microcirculatory perfusion indices quantified by hyperspectral imaging, biomarkers that reflect endothelium activation and damage, and clinical outcome.

Methods

Hyperspectral imaging of the knee area was performed in 95 intensive care patients with septic shock enrolled in a single-center observational study to obtain relative oxy/deoxyhemoglobin concentration values and construct anatomical maps of skin microcirculatory saturation. The blood was sampled to obtain concentrations of thrombomodulin, plasminogen activator inhibitor-1 (PAI-1), soluble intercellular adhesion molecule-1 (ICAM-1), soluble vascular cell adhesion molecule-1 (VCAM-1), angiopoietin-2, and syndecan-1. The spectrophotometrically obtained skin microvascular perfusion indices were compared to the mottling score and biomarker concentration. The association between mottling score, skin microcirculatory perfusion indices, and 28-day mortality was also analyzed.

Results

Microcirculatory oxygen saturation was significantly lower and total hemoglobin concentration was significantly higher in patients with a mottling score of 2 compared to those with a score of 0 (p = 0.02), with no difference between other scores. We found an association between microcirculatory oxygen saturation and PAI-1 levels (rho = − 0.3; p = 0.007). Increased mottling score and decreased microcirculatory oxygen saturation were predictive of 28-day mortality (mottling score 2 vs 0: OR 15.31, 95% CI 4.12–68.11; microcirculatory oxygen saturation: OR 0.90, 95% CI 0.85–0.95). Endothelial biomarkers did not increase the predictive value of skin microcirculatory perfusion indices.

Conclusions

Higher mottling scores are associated with lower microcirculatory oxygen saturation but with significant overlap between scores. Microcirculatory oxygen saturation is a quantitative measure of peripheral oxygenation and is more specific than the mottling score in predicting 28-day mortality.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2589-0) contains supplementary material, which is available to authorized users.

Mottling score is a strong predictor of 14-day mortality in septic patients whatever vasopressor doses and other tissue perfusion parameters

Background

Mottling score, a tissue perfusion parameter, is correlated with outcome in septic shock patients. However, its predictive value on mortality according to prognostic covariates such as vasopressor dose and other tissue perfusion parameters remains unknown.

Methods

Mottling score and tissue perfusion parameters were recorded at ICU admission (H0), H-6, H 12, and H-24 and used to assess the predictive value of mottling score on 14-day mortality in a development cohort. Results were then validated in an independent cohort of septic shock patients in Brazil.

Results

Overall, 259 patients with sepsis or septic shock were included, 14-day mortality was 37%. Factors associated with death were mottling score (OR 2.26 [95% CI, 1.72–2.97]), arterial lactate level (OR 1.29 [1.11–1.5]), and urine output < 0.5 ml/Kg/h (OR 3.03 [1.37–6.69]). The C statistic for the model was 0.90 in the development cohort and 0.76 in the validation cohort. The predictive value of mottling score was not affected by vasopressor doses (p for interaction = 0.33): OR for mottling score ranged from 2.34 [1.10–3.15] in patients without vasopressor to 3.84 [1.98–7.43] in patients infused with high doses of vasopressor (> 0.8 μg/kg/min). There was no difference in the effect of mottling score on mortality according to mean arterial pressure, heart rate, cardiac index, and urine output, but we found a significant interaction between arterial lactate level and mottling score (p = 0.04). The predictive value of the mottling score remains significant when using the recent SEPSIS-3 definition of septic shock. Finally, a decrease of mottling score during resuscitation was significantly associated with better outcome after adjustment on SOFA score (p = 0.001).

Conclusions

Our results support the high prognostic value of mottling score for 14-day mortality in septic patients, whatever vasopressor dosage and other perfusion parameters. Mottling score variations during resuscitation are also predictive of mortality.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2496-4) contains supplementary material, which is available to authorized users.

Assessment of Regional Perfusion and Organ Function: Less and Non-invasive Techniques

Sufficient organ perfusion essentially depends on preserved macro- and micro-circulation. The last two decades brought substantial progress in the development of less and non-invasive monitoring of macro-hemodynamics. However, several recent studies suggest a frequent incoherence of macro- and micro-circulation. Therefore, this review reports on interactions of macro- and micro-circulation as well as on specific regional and micro-circulation. Regarding global micro-circulation the last two decades brought advances in a more systematic approach of clinical examination including capillary refill time, a graded assessment of mottling of the skin and accurate measurement of body surface temperatures. As a kind of link between macro- and microcirculation, a number of biochemical markers can easily be obtained. Among those are central-venous oxygen saturation (S_cvO₂), plasma lactate and the difference between central-venous and arterial CO₂ (cv-a-pCO₂-gap). These inexpensive markers have become part of clinical routine and guideline recommendations. While their potential to replace parameters of macro-circulation such as cardiac output (CO) is limited, they facilitate the interpretation of the adequacy of CO and other macro-circulatory markers. Furthermore, they give additional hints on micro-circulatory impairment. In addition, a number of more sophisticated technical approaches to quantify and visualize micro-circulation including video-microscopy, laser flowmetry, near-infrared spectroscopy (NIRS), and partial oxygen pressure measurement have been introduced within the last 20 years. These technologies have been extensively used for scientific purposes. Moreover, they have been successfully used for educational purposes and to visualize micro-circulatory disturbances during sepsis and other causes of shock. Despite several studies demonstrating the association of these techniques and parameters with outcome, their practical application still is limited. However, future improvements in automated and “online” diagnosis will help to make these technologies more applicable in clinical routine. This approach is promising with regard to several studies which demonstrated the potential to guide therapy in different types of shock. Finally several organs have specific patterns of circulation related to their special anatomy (liver) or their auto-regulatory capacities (brain, kidney). Therefore, this review also discusses specific issues of monitoring liver, brain, and kidney circulation and function.

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.

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.

Tissue perfusion alterations correlate with mortality in patients admitted to the intensive care unit for acute pulmonary embolism: An observational study

We aimed to assess the relationship between alterations of tissue perfusion parameters at admission (highly predictive of mortality in septic shock) and outcome in patients admitted to the intensive care unit (ICU) for acute pulmonary embolism (PE). We conducted a retrospective study to analyze the association between arterial lactate level, skin mottling and urinary output, and 28-day mortality.Over a 22-year period, 317 patients with PE were identified but we finally analyzed 108 patients whose main diagnosis for ICU admission was acute PE. At admission, the sequential organ failure assessment score was 2 (0-6) and the simplified acute physiology score II was 29 (16-43). Thirty patients (28%) received vasopressors and 37 patients (34%) received thrombolytic therapy. Day 28 mortality rate was 25% (n = 27). When compared to 28-day survivors, nonsurvivor patients had higher lactate level (4.5 [2.3-10.3] mmol/L vs 1.4 [1-2.9] mmol/L, P < .0001), more frequent mottling around the knee area (56% vs 25%, P = .003) and a lower urinary output (during the first 6 hours) (0.35 [0-1] mL/kg/h vs. 0.88 [0.62-1.677] mL/kg/h, P = .0002). Mortality increased with the number of tissue perfusion alterations present upon admission, 8% for none, 21% for 1, 28% for 2, and finally reached 85% for 3 tissue perfusion alterations (P < .0001). In a multivariate analysis, the relationship between the number of tissue perfusion alterations and 28-day mortality was maintained after adjustment on the presence of shock and right ventricular dilation at admission.In ICU patients admitted for acute PE, tissue perfusion alterations correlated with 28-day mortality independently of blood pressure and right ventricular dilation.

Mottling score and skin temperature in septic shock: Relation and impact on prognosis in ICU

Introduction

Mottling score, defined by 5 areas over the knee is developed to evaluate tissue perfusion at bedside. Because of the subjective aspect of the score, we aimed to compare mottling score and skin temperature in septic shock with infrared thermography in ICU and the correlation to survival.

Methods

We conducted a prospective and observational study in a teaching hospital in France during 8 months in ICU. All patients with sepsis requiring vasoactive drugs were included. We recorded epidemiologic data, hemodynamic parameters, mottling score and skin temperature with a thermic camera of the 5 mottling areas around the knee (temperatures recorded with FLIR™ software) at bedside. Measures were performed at ICU admission (H0) and six hours after initial resuscitation (H6).

Results

46 patients were included. Median age was 69 (60–78), SOFA score 11 (8–12) mean SAPS II was 57±20 and 28-day mortality rate was 30%. Patients with mottling (score≥1), had a skin temperature of the knee significantly lower (30.7 vs 33,2°C p = 0.01 at H6) than patients without mottling (score = 0). Skin temperatures of the knee in mottling groups 1 to 5 were similar at H0 and H6. Neither mottling score nor skin temperature of the knee were associated with prognostic regarding day-28 mortality.

Conclusions

Skin temperature measured with infrared thermography technology around the knee is lower when mottling sign is present and sign microcirculation alterations. This method, compared to standard mottling score is objective and allows data collections. However, this method failed to predict mortality in ICU patients.

Pediatric Diabetic Ketoacidosis With Hypotensive Shock and Rash-An Unusual Presentation

We describe a previously healthy adolescent boy who presented with respiratory distress, hypotensive shock, and a diffuse erythematous rash. The final diagnosis was diabetic ketoacidosis. Caregivers should be alert to this unusual combination of symptoms in the emergency department setting in order to improve the recognition and management of children with new-onset diabetes.

A pilot study of the Leicester ED medical infrared imaging protocol in fever and sepsis

BACKGROUND

Medical Infrared Imaging (MII) is an investigative method that can be potentially used in emergency care to non-invasively detect thermal signatures associated with change in blood flow. We have developed a protocol for the use of MII in the Emergency Department (ED) and shown that it is feasible. To derive initial data for sample size calculations, we performed an exploratory study in patients with fever and sepsis.

METHODS

The Leicester MII protocol was used to image the temperature patterns along the arm among three patient groups (control, fever and sepsis) of a total 56 patients. Anatomical markers were used to divide this gradient into upper arm, forearm, hand and finger regions. Variations in measurements within and between these regions were described.

RESULTS

The thermal gradient down the arm was successfully extracted in all patients. The distribution of values in each region of the arm was described in control, fever and sepsis patients. There was a significant gradient between upper arm and finger in controls (2.75, p < 0.0001), but no gradient in fever (p = 0.944) or sepsis (p = 0.710). This was reflected in the finger/arm difference, which was of -2.74°C (±3.50) in controls, -0.39C (±2.48) in fever, and -1.80°C (±3.09) in sepsis.

CONCLUSIONS

This study found different thermal gradients along the arm in control and febrile groups, and defined the degree of individual variation. It is likely that the difference between upper arm temperature and finger temperature (representing the temperature gradient down the arm) may be more useful than absolute measurements in future studies.

Skin mottling score and capillary refill time to assess mortality of septic shock since pre-hospital setting

OBJECTIVES

The early identification of septic shock patients at high risk of poor outcome is essential to early initiate optimal treatments and to decide on hospital admission. Biomarkers are often used to evaluate the severity. In prehospital settings, the availability of biomarkers, such as lactate, is restricted. In this context, clinical tools such as skin mottling score (SMS) and capillary refill time (CRT) are more suitable. In this study, we describe prehospital SMS and CRT's ability to predict mortality of patients with septic shock initially cared in the prehospital setting by a mobile intensive care unit.

METHODS

Patients with septic shock who received prehospital medical care admitted to the intensive care unit were retrospectively analyzed.

RESULTS

Sixty-three patients were included. The origin of sepsis was mainly pulmonary (67%). Overall mortality reached 36%. No significant difference was observed in the duration of prehospital medical care between alive and deceased patients. Mean prehospital value of SMS was 3 ± 2 and mean prehospital value of CRT was 5 ± 1 s. A significant association was found between mortality and prehospital SMS (p = 0.02, OR[CI95] = 1.50 [1.08-2.15]) and prehospital CRT (p = 0.04, OR[CI95] = 1.53 [1.04-2.37]). After adjusting for confounding factors using propensity score, the relative risk of death was 6.58 for SMS > 2 and 2.03 for CRT > 4 s.

CONCLUSION

In this study, we report an association between prehospital SMS and CRT, and mortality of patients with septic shock. SMS and CRT are simple tools that could be used to optimize the triage and to decide early intensive care admission.

Recent advances in bedside microcirculation assessment in critically ill patients

Parameters related to macrocirculation, such as the mean arterial pressure, central venous pressure, cardiac output, mixed venous saturation and central oxygen saturation, are commonly used in the hemodynamic assessment of critically ill patients. However, several studies have shown that there is a dissociation between these parameters and the state of microcirculation in this group of patients. Techniques that allow direct viewing of the microcirculation are not completely disseminated, nor are they incorporated into the clinical management of patients in shock. The numerous techniques developed for microcirculation assessment include clinical assessment (e.g., peripheral perfusion index and temperature gradient), laser Doppler flowmetry, tissue oxygen assessment electrodes, videomicroscopy (orthogonal polarization spectral imaging, sidestream dark field imaging or incident dark field illumination) and near infrared spectroscopy. In the near future, the monitoring and optimization of tissue perfusion by direct viewing and microcirculation assessment may become a goal to be achieved in the hemodynamic resuscitation of critically ill patients.

Assessment of the adequacy of oxygen delivery

PURPOSE OF REVIEW

This article reviews the recent literature pertaining to assessment of the adequacy of oxygen delivery in critically ill patients with circulatory shock.

RECENT FINDINGS

The assessment of the adequacy of oxygen delivery has traditionally involved measurement of lactate, central (or mixed) venous oxygen saturation (ScvO2), and global hemodynamic markers such as mean arterial pressure and cardiac index. The search for noninvasive, reliable, and sensitive methods to detect derangements in oxygen delivery and utilization continues. Recent studies focus on near-infrared spectroscopy (NIRS) to assess regional tissue oxygenation, as well as bedside ultrasound techniques to assess the macrovascular hemodynamic factors in oxygen delivery.

SUMMARY

In this article, we review physiologic principles of global oxygen delivery, and discuss the bedside approach to assessing the adequacy of oxygen delivery in critically ill patients. Although there have been technological advances in the assessment of oxygen delivery, we revisit and emphasize the importance of a 'tried and true' method - the physical examination. Also potentially important in the evaluation of oxygen delivery is the utilization of biomarkers (e.g., lactate, ScvO2, NIRS). In complementary fashion, bedside ultrasound for hemodynamic assessment may augment the physical examination and biomarkers, and represents a potentially important adjunct for assessing the adequacy of oxygen delivery.

My patient has received fluid. How to assess its efficacy and side effects?

Many efforts have been made to predict, before giving fluid, whether it will increase cardiac output. Nevertheless, after fluid administration, it is also essential to assess the therapeutic efficacy and to look for possible adverse effects. Like for any drug, this step should not be missed. Basically, volume expansion is aimed at improving tissue oxygenation and organ function. To assess this final result, clinical signs are often unhelpful. The increase in urine output in case of acute kidney injury is a poor marker of the kidney perfusion improvement. Even if oxygen delivery has increased with fluid, the increase in oxygen consumption is not constant. Assessing this response needs to measure markers such as lactate, central/mixed venous oxygen saturation, or carbon dioxide-derived indices. If tissue oxygenation did not improve, one should check that cardiac output has actually increased with fluid administration. To assess this response, changes in arterial pressure are not reliable enough, and direct measurements of cardiac output are required. In cases where cardiac output did not increase with fluid, one should check that it was not due to an insufficient volume of fluid administered. For this purpose, volume markers of cardiac preload sometimes lack precision. The central venous pressure, in theory at least, should not augment to a large extent in fluid responders. The worst adverse effect of fluids is the increase in the cumulative fluid balance. In patients with acute respiratory distress syndrome (ARDS), the risk of aggravating pulmonary oedema should be systematically assessed by looking for increases in extravascular lung water, or, more indirectly, increases in central venous or pulmonary artery occlusion pressure. In ARDS patients receiving fluid, one should always keep in mind the risk of inducing/aggravating right ventricular dilation, which should be confirmed through echocardiography. The risk of increasing the intra-abdominal pressure should be carefully sought in patients at risk. Finally, fluid-induced haemodilution should not be neglected. Like for any drug which has inconsistent effectiveness and may exert significant harm, the correct fluid management should include a cautious and comprehensive assessment of fluid-induced benefits and side effects.

CE: Assessing Patients During Septic Shock Resuscitation

: In 2015, the Surviving Sepsis Campaign six-hour bundle was updated. The revised version now recommends documenting the reassessment of volume status and tissue perfusion after initial fluid resuscitation through a repeated focused examination. This article addresses the practice and interpretation of two components of this examination in adults: capillary refill time and skin mottling score. It further discusses how to best integrate these noninvasive parameters into the care of patients undergoing resuscitation for septic shock.

Marked regional endothelial dysfunction in mottled skin area in patients with severe infections

Background

Mottling around the knee, reflecting a reduced skin blood flow, is predictive of mortality in patients with septic shock. However, the causative pathophysiology of mottling remains unknown. We hypothesized that the cutaneous hypoperfusion observed in the mottled area is related to regional endothelial dysfunction.

Methods

This was a prospective, observational study in a medical ICU in a tertiary teaching hospital. Consecutive adult patients with sepsis admitted to ICU were included. After resuscitation, endothelium-dependent vasodilation in the skin circulation was measured before and after iontophoresis of acetylcholine (Ach) in the forearm and the knee area. We analyzed the patterns of induced vasodilatation according to the presence or absence of mottling and vital status at 14 days.

Results

We evaluated 37 septic patients, including 11 without and 26 with septic shock. Overall 14-day mortality was 22%. Ten patients had mottling around the knee (10/37, 27%). In the knee area, the increased skin blood flow following iontophoresis of Ach was lower in patients with mottled skin as compared to patients without mottled skin (area under curve (AUC) 3280 (2643–6440) vs. 7980 (4233–19,707), both P < 0.05). In the forearm area, the increased skin blood flow following iontophoresis of Ach was similar in patients with and without mottled skin. Among patients with septic shock, the increased skin blood flow following iontophoresis of Ach in the knee area was significantly lower in non-survivors as compared to survivors at 14 days (AUC 3256 (2600–4426) vs. 7704 (4539–15,011), P < 0.01). In patients with septic shock, the increased skin blood flow in the forearm area following iontophoresis of Ach was similar in survivors and non-survivors at 14 days.

Conclusion

Mottling is associated with regional endothelial dysfunction in patients with septic shock. Endothelial dysfunction in the knee skin area was more pronounced in non-survivors than in survivors.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1742-x) contains supplementary material, which is available to authorized users.

The effect of early goal-directed therapy for treatment of severe sepsis or septic shock: A systemic review and meta-analysis

PURPOSE

To assess the effects of early goal-directed therapy (EGDT) on reducing mortality compared with conventional management of severe sepsis or septic shock.

MATERIALS AND METHODS

We included a systemic review, using the Medline and EMBASE. Seventeen randomized trials with 5765 patients comparing EGDT with usual care were included.

RESULTS

There were no significant differences in mortality between EGDT and control groups (relative risk [RR], 0.89; 95% confidence interval [CI], 0.79-1.00), with moderate heterogeneity (I2=56%). The EGDT was associated with lower mortality rates when the mortality rate of the usual care group was greater than 30% (12 trials; RR, 0.83; 95% CI, 0.72-0.96), but not when the mortality rate in the usual care group was less than 30% (5 trials; RR, 1.03; 95% CI, 0.92-1.16). The mortality benefit was seen only in subgroup of population analyzed between publication of the 2004 and 2012 Surviving Sepsis Campaign guidelines, but not before and after these publications.

CONCLUSION

This meta-analysis was heavily influenced by the recent addition of the trio of trials published after 2014. The results of the recent trio of trials may be biased due to methodological issues. This includes lack of blinding by incorporating similar diagnostic and therapeutic interventions as the original EGDT trial.

Perfusion indices revisited

Monitoring of tissue perfusion is an essential step in the management of acute circulatory failure. The presence of cellular dysfunction has been a basic component of shock definition even in the absence of hypotension. Monitoring of tissue perfusion includes biomarkers of global tissue perfusion and measures for assessment of perfusion in non-vital organs. The presence of poor tissue perfusion in a shocked patient is usually associated with worse outcome. Persistently impaired perfusion despite adequate resuscitation is also associated with worse outcome. Thus, normalization of some perfusion indices has become one of the resuscitation targets in patients with septic shock. Although the collective evidence shows the clear relation between impaired peripheral perfusion and mortality, the use of different perfusion indices as a resuscitation target needs more research.

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.

Microcirculatory disorders during septic shock

PURPOSE OF REVIEW

Despite the progress made over the past 20 years in the treatment of septic shock, mortality remains high. Microcirculatory disorders raise considerable interest aiming to improve the understanding of the physiopathology of septic shock and its management.

RECENT FINDINGS

Numerous experimental and clinical studies have gradually focused on the analysis of microcirculatory blood flow and identified alterations in small vessels. These microcirculatory abnormalities appear early, are heterogeneous, and are directly linked to organ failure, as well as the patient's prognosis. These anomalies vary from one patient to the other, and their evolution during resuscitation cannot be predicted by the isolated analysis of global hemodynamic parameters such as blood pressure or heart rate.

SUMMARY

Microcirculatory disorders appear at a central place of the physiopathology and are highly associated with the patient prognosis; it therefore seems important to develop and integrate parameters reflecting tissue perfusion in the management of septic shock.

Research in Review: Driving Critical Care Practice Change

During the past year, studies were published that will lead to practice change, address challenges at the bedside, and introduce new care strategies. This article summarizes some of this important work and considers it in the context of previous research and practice. Examples of research-based practice changes include the performance and assessment of septic shock resuscitation, and the integration of tourniquets and massive transfusions in civilian trauma. Care challenges addressed include ethical considerations in light of the Ebola epidemic, infection prevention associated with chlorhexidine bathing, bedside alarm management, evidence to enhance moral courage, and interventions to mitigate thirst in critically ill patients. Research that portends future care includes a discussion of fecal microbiota transplant for patients with refractory infection with refractory infection with Clostridium difficile.

Early goal-directed resuscitation of patients with septic shock: current evidence and future directions

Severe sepsis and septic shock are among the leading causes of mortality in the intensive care unit. Over a decade ago, early goal-directed therapy (EGDT) emerged as a novel approach for reducing sepsis mortality and was incorporated into guidelines published by the international Surviving Sepsis Campaign. In addition to requiring early detection of sepsis and prompt initiation of antibiotics, the EGDT protocol requires invasive patient monitoring to guide resuscitation with intravenous fluids, vasopressors, red cell transfusions, and inotropes. The effect of these measures on patient outcomes, however, remains controversial. Recently, three large randomized trials were undertaken to re-examine the effect of EGDT on morbidity and mortality: the ProCESS trial in the United States, the ARISE trial in Australia and New Zealand, and the ProMISe trial in England. These trials showed that EGDT did not significantly decrease mortality in patients with septic shock compared with usual care. In particular, whereas early administration of antibiotics appeared to increase survival, tailoring resuscitation to static measurements of central venous pressure and central venous oxygen saturation did not confer survival benefit to most patients. In the following review, we examine these findings as well as other evidence from recent randomized trials of goal-directed resuscitation. We also discuss future areas of research and emerging paradigms in sepsis trials.

Exploration of skin perfusion in cirrhotic patients with septic shock

BACKGROUND & AIMS

Skin perfusion alterations are early and strong predictors of death in patients with septic shock. Cirrhosis is associated with systemic vasodilation and increases mortality from septic shock. We aimed at assessing whether the mottling score and tissue oxygen saturation (StO2) could be used as early predictors of death in cirrhotic patients with septic shock.

METHODS

This observational study included cirrhotic patients with septic shock. Each 6 h during the first 24 h, we collected data reflecting macrocirculation (mean arterial pressure, heart rate, central venous pressure, and cardiac output) and organ perfusion (arterial lactate, urinary output, ScvO2, mottling score, thenar, and knee StO2). Data of 75 non-cirrhotic patients with previously reported septic shock were used as control.

RESULTS

42 cirrhotic patients were included. Mortality at day 14 was 71%. At H6, parameters reflecting macrocirculation were not associated with mortality, whereas higher arterial lactate and mottling score were associated with death. Mottling score was the strongest predictor of mortality (sensitivity=0.63, specificity=1, OR=42.4 (2.3-785.9)). At H6, knee StO2 decreased in non-survivors and predicted death (sensitivity=0.45, specificity=1). In comparison with control, mottling kinetic was different in cirrhotic patients (delayed mottling appearance in non-survivors, earlier mottling disappearance in survivors). Knee StO2 and skin perfusion, assessed by laser-Doppler, were higher in cirrhotic patients.

CONCLUSIONS

Mottling score and knee StO2 at H6 were very specific predictors of death in patients with cirrhosis and septic shock. Their sensitivity was lower in cirrhotic patients due to delayed mottling appearance and higher knee StO2 related to higher skin perfusion.

Fluid resuscitation should respect the endothelial glycocalyx layer

Endothelial glycocalyx degradation induced by fluid overload adds to the concern of a detrimental effect of uncontrolled fluid resuscitation and the risk of unnecessary fluid infusion. As a consequence, the use of new tools for monitoring response to fluids appears promising. From that perspective, the monitoring of plasma concentration of glycocalyx degradation markers could be useful.

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.

New tools for optimizing fluid resuscitation in acute pancreatitis

Acute pancreatitis (AP) is a frequent disease with degrees of increasing severity responsible for high morbidity. Despite continuous improvement in care, mortality remains significant. Because hypovolemia, together with microcirculatory dysfunction lead to poor outcome, fluid therapy remains a cornerstone of the supportive treatment. However, poor clinical evidence actually support the aggressive fluid therapy recommended in recent guidelines since available data are controversial. Fluid management remains unclear and leads to current heterogeneous practice. Different strategies may help to improve fluid resuscitation in AP. On one hand, integration of fluid therapy in a global hemodynamic resuscitation has been demonstrated to improve outcome in surgical or septic patients. Tailored fluid administration after early identification of patients with high-risk of poor outcome presenting inadequate tissue oxygenation is a major part of this strategy. On the other hand, new decision parameters have been developed recently to improve safety and efficiency of fluid therapy in critically ill patients. In this review, we propose a personalized strategy integrating these new concepts in the early fluid management of AP. This new approach paves the way to a wide range of clinical studies in the field of AP.

Monitoring the microcirculation in critically ill patients

Alterations in microvascular perfusion have been identified in critically ill patients, especially in sepsis but also in cardiogenic shock, after cardiac arrest, and in high-risk surgery patients. These alterations seem to be implicated in the development of organ dysfunction and are associated with outcome. Even though microvascular perfusion can sometimes be homogenously decreased as in acute hemorrhage or in non-resuscitated cardiogenic shock, heterogeneity of perfusion is observed in sepsis and in resuscitated hemorrhagic/cardiogenic shock. Heterogeneity of perfusion has major implications for monitoring, as many techniques cannot detect microcirculatory alterations when heterogeneity of flow is present in significant amount. Indeed, devices such as laser Doppler or O2 electrodes and near-infrared spectroscopy have a relatively large sampling volume and measurements are affected by the highest values in the field. Using these techniques during a vascular occlusion test may help to characterize microvascular reactivity; however, microvascular reactivity sometimes fails to represent actual microvascular perfusion. Videomicroscopic techniques can nowadays be applied at bedside but are still restricted to some selected patients (quiet or sedated patients). Tissue PCO2 is an elegant alternative but is not yet broadly used. In this manuscript, we discuss the main advantages and limitations of the techniques available for bedside evaluation of the microcirculation in critically ill patients.