The Path from SIRS to Sepsis
We can help septic patients simply but effectively
By DeWayne Miller
What exactly is systemic inflammatory response syndrome (SIRS) or sepsis and why should you care during the transport to the emergency department (ED)? What can you do during the short time you have this patient that will actually make a difference? Something as simple as starting IV fluids can make a big difference.
Sepsis is one of the leading causes of death in the United States. It typically starts as a mild infection and moves along the severity scale until finally reaching the worst phase, which is septic shock. Once septic shock has reared its ugly head, the mortality rate ranges from 35 to 50%. Septic shock is a difficult syndrome to reverse. It is much easier to treat the early less severe stages of sepsis.
It would seem obvious that we should be providing treatment before the process reaches the severe stage. That should eliminate most of the cases associated poor outcomes. The problem is there is no way of predicting which patient will become critically ill.
Therefore, we all should become very familiar with the early signs and symptoms of SIRS. Armed with this knowledge and being sensitive to when an infection may be starting, we can perhaps intervene early and avoid the hypotensive critically ill stage.
SIRS is a sign of the body's response to an insult or injury. This can be from infection, trauma, ischemia or a variety of other clinical conditions. SIRS is defined as exhibiting 2 or more of the following symptoms:
- sustained heart rate greater than 90 bpm
- Core temperature more than 38o C (100.4o F) or less than 36o C (96.8o F)
- Respiratory rate of more than 20 breaths per minute or arterial carbon dioxide tension (PaCO2) of less than 32 mm Hg.
- Abnormal white blood cell count (<4000 or >12,000/mm3 ) or > 10% bands
We can help increase the patient's ability to fight the infection with just a few simple therapies. Starting these therapies in the initial 24 hours of the illness is closely related to sepsis survival.
That may sound like a very obvious and simple fact but early symptoms are easily overlooked and often ignored. The patient, who has become restless, has low urine output (oliguria) and eventually experiences hypotension is showing that the infection has a strong head start on treatment.
Sepsis and Septic Shock
Those with the highest risk to develop sepsis are the very young (such as preterm infants), the very old and anyone with a compromised immune system (examples: HIV, chemotherapy or steroid treatments). There are various levels of "sepsis syndromes". The severity of the patient's condition resulting from the number of organ systems involved determines where on the sepsis scale each patient resides.
Uncomplicated sepsis can be anything such as the flu, dental abscesses, and skin infections. Millions of people each year experience these and recover at home without hospital treatment.
Severe sepsis involves organ dysfunction, hypoperfusion and hypotension. This can include altered mental status, decreased urine output, and lactic acidosis, etc. This stage is usually responsive to fluid resuscitation.
Septic shock is not responsive to fluid therapy alone and requires vasopressors. Patients remain in the septic shock category as long as this support is required to maintain perfusion. Mortality from septic shock has traditionally been close to the 50% range. Recent studies have shown mortalities of 20-30% may be possible with current therapeutic approaches provided in the sepsis bundles.
Prior to 2002 uniform practice guidelines for management of sepsis did not exist. The European Society of Intensive Care Medicine, the International Sepsis Forum, and the Society of Critical Care Medicine launched the "Surviving Sepsis Campaign". Data from several clinical trials was used to develop evidence-based guidelines that were published in 2004. These were updated 4 years later.
These groups knew that often there is an extensive lag in time after publishing new practice guidelines until they are integrated into clinical practice, and some are never fully adopted. Aware of the shortcomings of the medical world the Campaign developed a multifaceted model to help move the guidelines into place.
This model included international meetings, recruitment of - sites, physicians and nurses. Many other resources were also developed but the most pertinent to this article is the creation of treatment "bundles". These stemmed from key elements of the new guidelines.
A field patient with an infective history, coupled with two or more SIRS signs or symptoms should raise a flag during your assessment.
Ensure that the patient's airway is secure and begin oxygen to maintain saturations of 92% or greater. Obtain IV access and cardiac monitoring. If authorized, obtain blood samples for the hospital laboratory.
Treatment starts with fluid boluses of 20 ml/kg over 30 minutes and repeated until symptoms improve or signs of volume overload present. Generally, 4 to 5 liters of crystalloids are required before symptoms may start to improve. While EMS providers may not deliver this amount of fluid during their care, beginning volume resuscitation early may be beneficial.
Once adequate fluid volume is achieved a mean arterial pressure (MAP) of 65 mmHg is the goal. If vasopressors are needed norepinephrine or dopamine are both acceptable options. Norepinephrine exerts peripheral vasoconstriction without affecting cardiac output, while dopamine provides peripheral vasoconstriction plus positive inotropic force. Decisions are typically based on the heart rate and directed to avoid increasing the rate if the patient is already tachycardic.
It is not clear which patients will move from sepsis down the path to septic shock. One thing we know is when treatment is started early and adheres to specific guidelines such as "sepsis bundles" which are based on Early Goal Directed Therapy, outcomes are usually better.
Bundles / EGDT
Treatment bundles are a group of therapies that are intended for use together. Early Goal Directed Therapy (EGDT) is a key element in a treatment bundle utilizing specific interventions based on lab and physiologic parameters. EGDT is intended to provide direction for titration of IV fluids, vasopressors, and transfusions to attempt to quickly correct the physiologic derangements brought on by severe sepsis. Studies to date have shown a decrease in mortality by utilizing these guidelines. Details can be found at www.survivingsepsis.org/.
Antibiotic therapy should be started as soon as possible. It is helpful to draw blood cultures first but only if this causes no delay. Retrospective cohort analyses have suggested that early antibiotic administration is associated with better survival in severe sepsis or septic shock. These patients have a worse chance of survival for each hour antibiotics are delayed during the first six hours starting at the onset of hypotension.
Broad-spectrum antibiotic coverage of both gram-positive and gram-negative bacteria is recommended. Few guidelines exist for initial selection of antibiotics and the decision is complex. Factors to consider are comorbidities, patient history (hospital vs community acquired), and local resistance patterns. Involving the local infectious disease specialist can be helpful. Poor outcomes are associated with inappropriate coverage.
If a source of infection can be identified it should be quickly dealt with. Examples are central lines, foley catheters, and wounds requiring surgical drainage.
The hypothalamus, pituitary gland, and the adrenal glands work in conjunction secreting various hormones to help maintain homeostasis. While it has shown that adrenal activity is crucial to survival in states of physiologic stress what has yet to become clear is the best role for corticosteroid therapy in the treatment during severe sepsis and septic shock states.
Several studies have been completed but show conflicting results. There has yet to be shown a routine role for corticosteroid use in sepsis and severe sepsis. For septic shock unresponsive to fluids and vasopressors it may be beneficial to provide corticosteroid therapy if within eight hours of onset of shock (shock = B/P < 90 mmHg after completion of fluid volume replacement and vasopressors therapy for at least one hour).
Lab tests that measure adrenal function should not be used to attempt selection of patients that will benefit from corticosteroid therapy.
Anyone diagnosed with sepsis should be monitored closely. ICU placement is optimal for tight guideline adherence.
Points to remember
- Sepsis is characterized by SIRS plus infection.
- Early recognition and prompt protocol guided treatment improves outcomes.
- Repeat fluid boluses until hypoperfusion is gone or signs of volume overload began.
- Early broad-spectrum antibiotic coverage improves outcomes.
Sepsis is a condition we encounter often. When assessing a patient that appears ill, always remember and look for the SIRS symptoms. Help develop a protocol to guide therapy for your service or department. Find an existing protocol and tailor it to your specific region or service. If your protocols or transport times do not allow the large volumes of fluid mentioned, simply having intravenous access and fluids started will make timely administration easier to accomplish once the need is confirmed at the receiving hospital.
It's our job to be alert for subtle signs and symptoms. The patient's chances for a good outcome improve if we intervene early. Waiting to be aggressive until hypotension presents is far to late.
- Angus et al. Epidemiology of severe sepsis in the United States: analysis of incidence, outcome, and associated costs of care. Crit Care Med (2001) vol. 29 (7) pp. 1303-10.
- Micek et al. Before-after study of a standardized hospital order set for the management of septic shock. Crit Care Med (2006) vol. 34 (11) pp. 2707-13
- Jones et al. Prospective external validation of the clinical effectiveness of an emergency department-based early goal-directed therapy protocol for severe sepsis and septic shock. Chest (2007) vol. 132 (2) pp. 425-32
- Kumar et al. Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med (2006) vol. 34 (6) pp. 1589-96.
- Sprung et al. Corticosteroid therapy for patients in septic shock: some progress in a difficult decision. Crit Care Med (2011) vol. 39 (3) pp. 571-4.