Acute respiratory distress syndrome (ARDS) is a life-threatening pulmonary disorder that complicates the recovery picture by preventing oxygen from entering the bloodstream and nourishing body cells. A complex problem that requires constant vigilance by respiratory therapists armed with an array of interventions, ARDS is one of the most dreaded diagnoses in the critical care environment.
Risk Factors
Alicia Simpson, MSN, RN, a clinical nurse in the medical ICU at The Mount Sinai Medical Center, New York, NY, explained: “Patients with pre-existing pulmonary or respiratory conditions, such as asthma or pneumonia, are at risk for ARDS, as well as those with cardiac issues who can go into congestive heart failure from fluid overload. Remember, the ‘A’ in ARDS stands for acute, and this is an acute condition that can occur in just about anyone who is on a ventilator.”
Sepsis is a leading risk factor for ARDS in general patient populations, and trauma patients are also particularly susceptible to it, said Colleen Heafey, MSN, RN, CCRN-CMC, clinical nurse specialist in the critical care division at Lowell General Hospital, Lowell, MA. “We also see ARDS in patients with respiratory disorders, some critically ill [obstetrics] patients, and occasionally patients who have massive transfusions.”
Other patients at risk for ARDS include those with pneumonia, a suppressed immune system and chronic lung disease, added Sandy Carlin, RN, CCRN, charge nurse in the ICU at Shady Grove Adventist Hospital, Rockville, MD.
Assessment
The onset of ARDS is unexpected and abrupt, Simpson said. “I can be standing there at the bedside, raising the FiO2 [fraction of inspired oxygen] up to 50, 60, 70, or 80, and nothing happens,” she explained. “When there’s no improvement from the increased oxygen, we have to increase PEEP [positive end-expiratory pressure] to overcome the resistance from stiff alveoli. I’ll quickly run an arterial blood gas and typically find the patient has a low P02 and is acidotic because of the impaired gas exchange.”
Astute critical care clinicians keep an eye out for early signs and symptoms of ARDS, Carlin said. “We watch for increased respiratory distress, as well as a worsening chest X-ray,” she said. “We would also notice an increase in pulmonary inspiratory pressures on the ventilator because of decreased lung compliance and pulmonary edema.”
The secondary phase of ARDS makes clinical management even more difficult. “A situation occurs with a ventilation/perfusion mismatch that keeps oxygen from passing from the alveoli to the capillaries, and oxygen saturation doesn’t rise even when there’s plenty of oxygen in the lungs,” Carlin noted.
Constant Vigilance
Patients with ARDS require immediate medical interventions. “The first goal is to treat the underlying cause, and the second is to reduce the inflammatory process,” Simpson said. “We give either methylprednisolone or hydrocortisone to reduce inflammation, and the blood glucose level starts rising in response to the steroids. We may need to start an insulin drip at that point, so we now have an endocrine problem on top of a respiratory complication.”
Care for patients with ARDS requires constant vigilance by respiratory therapists ready with an arsenal of interventions and multidisciplinary support, Simpson added. “We sedate these patients thoroughly and sometimes use a paralytic drug as well to keep them still and compliant with the ventilator so they don’t damage their alveoli,” she said. “Stabilizing a patient’s hemodynamic status requires interdisciplinary coordination to minimize the risk of mortality due to ARDS complications.”
Preventing ARDS
The best treatment for ARDS is prevention, Heafey said. “We watch patients from the point of admission, looking for those with an increasing oxygen demand that seems to be out of context,” she said. “These patients fit the criteria for a Rapid Response Team call if they’re not already in intensive care, and they’ll be transferred to ICU for intubation and mechanical ventilation.”
Once patients are in ICU, they constantly adjust respiratory support to promote the best outcomes, Heafey added. “We start with low PEEP to recruit alveoli and increase it only as needed to provide optimal oxygenation,” she said. “We also lower the tidal volume, per ARDS net protocols, to reduce pulmonary damage.”
Jennifer Radtke, BSN, RN, CEN, trauma program manager at The University of Tennessee Medical Center, Knoxville, discussed the role emergency department staff play early on. “In older adults, chest injuries can cause significant pulmonary contusions that don’t show up right away,” she said. “We give a lot of fluids during resuscitation because trauma patients are often in hypovolemic shock, [but] this can increase the edema in the lung-injured tissue that leads to ARDS. We need to carefully balance fluids to avoid over-resuscitation.”
At Shady Grove, Carlin said they employ a very successful bundle of care to prevent ventilator-associated pneumonia (VAP) with subsequent ARDS.
“We elevate the head of the bed at least 30 degrees, give regular sedation vacations to check for readiness for extubation, use peptic ulcer disease prophylaxis, employ [deep vein thrombosis] prophylaxis, suction the mouth and back of the throat frequently to reduce secretions and bacteria, and get patients out of bed in the chair or in a chair position in bed for an hour a day,” she explained. “We’ve had no VAP in 2010, or so far in 2011.”
Back to the Basics
Critical care nurses add high-touch care to the high-tech respiratory support. “Although we focus on ventilation and oxygenation, we also get back to the basics,” Heafey said. “We’ll put them on kinetic rotating beds early on, prone patients with ARDS as needed, provide meticulous skin and mouth care, and institute a bowel regimen.
Heafey advocates following the FAST HUG mnemonic developed by the American Association of Critical-Care Nurses that reminds critical care nurses to address seven best practices in their patients: Feeding, Analgesia Assessment, Sedation Assessment, Thromboprophylaxis, Head of the Bed, Ulcer Prophylaxis and Glycemic Control.
“It’s much easier to prevent complications than to treat them, and these patients are already so debilitated from ARDS that any complication makes things worse,” Heafey continued. “The mortality rate for ARDS is between 30 and 50 percent, and we do everything we can to improve the odds for our patients.”
Sandy Keefe is a frequent contributor to ADVANCE.
