Sepsis-3: The new definitions : Nursing2020 Critical Care (2024)

Patients with sepsis continue to experience significant morbidity and mortality despite coordinated effort, beginning with the first international sepsis definition conference in 1991. Sepsis is the sixth most common reason for hospital admission in the United States, and patients with sepsis are more likely to have longer hospital stays with higher costs—along with higher rates of discharge to long-term care—than any other discharge diagnosis.^1-3 The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) were published in 2016.⁴ This article will help highlight the significance of these changes and potential practice changes for nurses.

Redefining sepsis

Sepsis is now defined as “life-threatening organ dysfunction caused by a dysregulated host response to infection.”⁴ (See Sepsis definitions, 1992-2016.) Sepsis is the result of an infection and encompasses the patient's response to that infection and resulting organ dysfunction. Because the new definition of sepsis is now inclusive of patients with organ dysfunction and increased risk of mortality, the term severe sepsis has been removed from Sepsis-3.⁴

Systemic inflammatory response syndrome (SIRS) criteria were also removed from sepsis definition in recognition of its lack of specificity.⁴ While some patients with infections may fit the SIRS criteria, SIRS may also occur in multiple noninfectious disease states such as trauma, burns, surgery, or pancreatitis.^5,6 In addition, the new sepsis definition incorporates the current understanding of sepsis physiology; it includes the individual host's activation of both proinflammatory and anti-inflammatory responses to infection, which can then lead to organ dysfunction. Patients who have organ dysfunction in response to an infection have a mortality greater than 10%.⁴ One of the goals of the new definition was to bring increased awareness and encourage additional assessment of patients with a known sepsis risk.

Septic shock

Septic shock is newly defined as a subset of sepsis in which underlying circulatory and cellular metabolism abnormalities are profound enough to substantially increase mortality.⁴ The new definition includes criteria that help differentiate shock due to sepsis versus cardiovascular collapse.

The new definition is based on systematic reviews, a meta-analysis, a Delphi study among the consensus group, and large, retrospective cohort studies. Septic shock criteria have also been updated, and there is now a vasopressor requirement to maintain a mean arterial pressure (MAP) of 65 mm Hg or greater and a lactate level less than 2 mmol/L after adequate volume resuscitation.⁴

Screening for sepsis

Currently, unlike other medical conditions such as stroke or acute myocardial infarction, there is no single clinical test that is specifically and directly diagnostic of sepsis. Screening tools can help to identify potential patients that may require closer assessment for earlier intervention. The sepsis syndrome triad includes infection, the patient's individual response to that infection, and the resulting organ dysfunction.

Although the SIRS criteria have been removed from the current sepsis definition, they may still remain useful for the identification of infection and can be used to help broadly identify or screen potential patients who are at risk for sepsis.^4,7,8 Earlier recognition and assessment of infection and sepsis can lead to earlier implementation of the components of the bundles; this implementation may also lead to better outcomes and decreased mortality for patients (see Sepsis and septic shock bundles).⁷ Patients should be screened for infection upon entry to the healthcare system and routinely after admission, and this screening should include assessment for tissue hypoxia and new organ dysfunction.

Quantifying tissue hypoxia

Lactate levels have been used as a marker of tissue hypoxia due to inadequate oxygen delivery in sepsis.⁹ However, lactate levels cannot be used in isolation as a “test” for sepsis but only as an adjunctive assessment tool. Elevated lactate levels can be attributed to lactic acidosis from tissue hypoxia (Type A) or from nontissue hypoxic states (Type B) resulting from the use of beta-agonists, diabetic ketoacidosis, liver failure, and other conditions.¹⁰

Quantifying organ failure

The Sequential Organ Failure Assessment (SOFA) score is used in critical care to describe organ dysfunction or failure and is based on several important concepts (see SOFA score).¹¹ Organ failure is a continuum, and it is useful for clinicians to have a tool that describes its degrees of severity rather than a simple number or score. Patients with a suspected infection and a SOFA score of 2 or greater have an increased (greater than 10%) risk of mortality.¹² The SOFA score requires lab work and assessments that are best performed in an ICU, and it has a better predictive value when used in that setting. For patients with chronic conditions (that is, those with a higher baseline score), a change in SOFA score of 2 or more points also signals higher morbidity risk.

Quick SOFA (qSOFA) score

As part of Sepsis-3, a new scoring system was developed that could be easily and quickly implemented in most clinical settings outside the ICU without technology or lab tests (see qSOFA score). The qSOFA score consists of three clinical components: the patients' Glasgow Coma Scale (GCS), systolic BP, and respiratory rate.¹² Altered mental status may also be used as a surrogate for GCS and describes a lower GCS. Patients who have a suspected infection and qSOFA score of 2 or greater have a greater risk for morbidity due to sepsis.

This new measure was retrospectively tested in several large patient databases.¹² Patients with infection and a positive qSOFA score had higher mortality and longer ICU stays than patients who did not, and the qSOFA score was predictive in non-ICU patients.

Case review

Ms. S is a 56-year-old female who was admitted to a surgical unit with cholecystitis after percutaneous drainage of her gall bladder. Initial vital signs were: temperature, 96.6° F (35.9° C); heart rate, 127 beats/minute; respiratory rate, 26 breaths/minute; and BP, 98/52 mm Hg. Her MAP was 67 mm Hg and she had a GCS of 15. Ms. S triggered a sepsis alert as soon as her assessment was entered into the electronic medical record because she had two or more abnormal SIRS criteria: temperature, heart rate, and respiratory rate.

Ms. S's healthcare provider was notified of her positive SIRS criteria along with the new Sepsis-3 qSOFA score of 2, based on her high respiratory rate and BP. A stat lactate test was ordered. Her initial lactate level was 3.1 mmol/L. Normal lactate levels usually range from 0.5 mmol/L to 2.2 mmol/L.¹⁰

Ms. S's repeat vital signs after 1 hour were: temperature, 96.4° F (35.8° C); heart rate, 130 beats/minute; respiratory rate, 24 breaths/minute; and BP, 70/51 mm Hg. Her MAP was 57 mm Hg and her GCS had decreased slightly to 13. Her new qSOFA score was 3; taken together in accordance with the Sepsis-3 definitions, these signaled organ dysfunction and increased mortality risk.

Ms. S's nurse notified the rapid response team, which initiated an immediate fluid bolus with 3 L of 0.9% sodium chloride based on Ms. S's weight of 90 kg (30 mL/kg). The rapid response team also completed stat blood cultures, began Ms. S on a broad-spectrum antibiotic, and obtained repeat a lactate level after the fluid bolus.

The patient was transferred to the ICU and her BP remained low (80/40 mm Hg) with a MAP of 53 mm Hg after the third liter of 0.9% sodium chloride was infused and stat antibiotics were given. A central line was inserted and norepinephrine was started to maintain a MAP of 65 mm Hg or higher. Ms. S's repeat lactate level was 2.2 mmol/L. Ms. S's nurse noted that she currently met two criteria of septic shock: persistent hypotension despite fluid resuscitation requiring a vasopressor, and a lactate level greater than 2 mmol/L after fluid resuscitation.

She infused an additional 2 L of 0.9% sodium chloride after a passive leg raise test, bedside cardiovascular ultrasound, and stroke volume results showed fluid responsiveness. By the next morning, Ms. S was weaned off norepinephrine and was awake and alert. Her central line was discontinued later that evening and she was transferred to the medical-surgical unit on antibiotics with her sepsis resolved.

Additional changes

Since October 2015, the Centers for Medicare and Medicaid Services (CMS) has used and will continue to use the 2003 definitions of sepsis, severe sepsis, and septic shock to capture mandated reported data based on discharge diagnosis. Currently, there are no plans to revise the sepsis CMS core measure, or SEP-1, to implement public reporting or payment penalties through fiscal year 2017.¹³ This delay may be related to Sepsis-3, evolving research and response to these definitions, and the new sepsis guidelines slated for publication early in 2017.

These forthcoming guidelines may also influence changes to the sepsis bundles. However, the Surviving Sepsis Campaign bundles have already incorporated the new Sepsis-3 definitions into their recommendations for sepsis screening and management.¹⁴ Recommendations include initial screening for suspected or confirmed infection, screening for organ dysfunction and management of sepsis, and identification and management of initial hypotension. The qSOFA may be an additional tool to help identify patients who are at increased risk.

The CDC has also recently implemented a comprehensive sepsis campaign to improve patient safety by increasing provider and patient awareness of the condition that incorporates the new definitions. The campaign focuses not only on early recognition and treatment but also on preventing sepsis, and provides education for providers, patients, and their families.¹⁵

Implications for practice

While the new definitions will be progressively incorporated into clinical use, there may be a period of discordance as the sepsis literature and research catches up with the 2016 definitions for sepsis and septic shock. Using the new definitions will help clinicians and researchers understand what interventions improve outcomes along with what resources are needed. Sepsis teams should work to incorporate the new definitions into their sepsis protocols and coding. Every nurse should not only be aware of the new definitions but also what their facility's polices and protocols are for screening and managing patients with sepsis.

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