Your transport team is called to the intensive care unit of a 68-bed community hospital 30 nautical miles away for a 64 year-old male admitted three days ago with “flu-like” symptoms. The patient had been admitted to the hospital by his primary care provider for general malaise, a temperature of 100.9F and a high white blood cell count.
Sputum cultures were positive for gram-negative rods and appropriate oral antimicrobial coverage had been initiated. Early this morning, the patient experienced increased dyspnea, weakness and confusion. He was transferred to the ICU for further work up.
Upon your arrival, the patient’s condition appears to have declined significantly. He is intubated and mechanically ventilated, appears quite anxious and is repeatedly triggering the ventilator high-pressure alarm. A dopamine drip is infusing through a recently-inserted, right subclavian triple-lumen central venous catheter. The dopamine is currently running at a dose of 15 micrograms per kilo per minute. He received 40 milligrams of Lasix intravenously for low urine output. Current vital signs include a heart rate of 124 bpm, blood pressure of 82/48 (MAP of 59 mmHg), respiratory rate of 22 breaths/minute and an oxygen saturation of 91 percent on 100 percent oxygen fiO2. Central venous pressure measured at the distal lumen of the central venous catheter is three mmHg and cardiac output as measured by an esophageal doppler was 9.4 liters/minute.
How would you explain these assessment findings? Is the patient receiving appropriate management in the ICU based on best practices? How would you and your team proceed with management and transport?
Severe Sepsis and Septic Shock
Severe sepsis and septic shock are serious and possibly lethal complications in many critically ill patients. In 2001, Angus et al. reported the national mortality rate from severe sepsis was at 215,000 patients, higher than those that died from heart attacks and lung cancer1. Recognition and early management are key to patient survival. Critical care transport personnel may play a pivotal role in this process.
In the above scenario, the patient was displaying clinical signs of a Systemic Inflammatory Response Syndrome (SIRS) several days before ICU admission. Signs include more than one of the following:
- Temperature > 100.4°F or < 96.8°F (> 38°C or < 36°C)
- Heart rate > 90 beats/min
- Tachypnea, as manifested by a respiratory rate > 20 breaths/min. or hyperventilation, as indicated by a PaCO2 < 32 mm Hg
- Alteration of white blood cell count > 12,000 cells/mm3, < 4,000 cells/mm3, or the presence of > 10 percent immature neutrophils
As the patient’s course progressed, he began showing signs of severe sepsis and septic shock including hypotension (SBP < 90 and MAP < 70 mmHg), oliguria, dysfunction of one or more vital organ systems, and elevated serum lactate2. Appropriate and aggressive hemodynamic and ventilatory management are cornerstones to therapy. Current evidence-based practice places management into “bundles.”
In 2002, Surviving Sepsis Campaign was formed in collaboration with the European Society of Intensive Care Medicine, International Sepsis Forum, and the Society of Critical Care Medicine. Surviving Sepsis was established to help meet the challenges of sepsis in the areas of diagnosis and management. The goal is to reduce overall mortality related to sepsis.
Sepsis Bundles
A bundle is “a group of interventions related to a disease process that, when implemented together, result in better outcomes than when implemented individually.” (www.IHI.org)
There are two “bundles” that have been identified. The resuscitation bundle is implemented within the first 6 hours of presentation. Aggressive management is initiated for hypotension and/or a serum lactate > 4 mmol/L. The management bundle consists of goals that must be completed within 24 hours, for patients with severe sepsis, septic shock and/or lactate > 4 mmol/L. For the purpose of this discussion, we will concentrate on the resuscitation bundle, as it is more applicable to what the critical care transport provider will need in their arsenal for patient stabilization and safe transport to tertiary care. For a more in-depth discussion on sepsis and utilization of sepsis bundles, visit www.survivingsepsis.org.
Resuscitation and Management Priorities
Based upon clinical presentation, this patient is in septic shock evidenced by hypotension and multiple organ dysfunction (oliguria indicating renal dysfunction, respiratory failure and altered level of consciousness indicating CNS dysfunction). Additional assessment parameters should include arterial blood gas and serum lactate measurements, as well as a central venous oxygenation reading (ScvO2). This reading can be taken from the distal lumen of the central venous catheter.
The patient has altered vascular permeability and a low systemic vascular resistance as a result of the systemic inflammatory response. Evidence of this includes a low CVP reading, indicating a relative hypovolemia and a high cardiac output secondary to reduced afterload. Additionally, this patient may have alterations in respiratory and ventilatory function as a result of the inflammatory process.
Management priorities include interventions to maximize oxygen delivery to cells and optimize preload, afterload and myocardial contractility. Ventilatory management will be directed towards protecting the lungs while attempting to maximize oxygenation. For a more detailed discussion surrounding mechanical ventilation strategies, refer to my previously written column “Breathing Life into ARDS.”
Hemodynamic management first involves aggressive fluid resuscitation in the form of isotonic crystalloid. Boluses at 20 ml per kilo are delivered with a target CVP goal of 8-12 mmHg. Hypotension refractory to fluid resuscitation will require vasopressor therapy. Norepinephrine is the agent of choice. Target mean arterial pressure (MAP) is 65 mmHg3. Resuscitation will be guided by resuscitation endpoints including pH, serum lactate level and ScvO2 (70-90 percent is considered normal).
Air Medical Transport Considerations
The complicated task of managing a patient in septic shock becomes even more challenging when transport comes into the equation. Minimizing oxygen consumption becomes difficult at best. Sedation, analgesia and possibly neuromuscular blocking agents are considerations to minimize oxygen consumption. These patients are often “pressor dependent” at the time that you are called to transport. Ensure that you have an adequate amount or the ability to quickly mix more enroute. Ensure all lines are accessible. Some transport programs are utilizing bedside point of care testing. This could possibly be useful if you are able to obtain serum lactate levels or trend venous saturations. During particularly long transports, these readings are useful in determining adequacy of resuscitation.
References
- 1 Angus DC, Linde-Zwirble WT, Lidicker J, et al. Epidemiology of severe sepsis in the United States: analysis of incidence, outcome, and associated costs of care. Crit Care Med. 2001;29(7):1303-1310.
- 2 Dellinger RP et al. Surviving Sepsis Campaign: International guidelines for management of severe sepsis and septic shock 2008. Crit Care Med. 2008; 36(1): 296-327.
- 3 Rivers E et al. Early Goal-Directed Therapy in the Treatment of Severe Sepsis and Septic Shock. New England Journal of Medicine 2001; 345:1368-1377.
