Zosyn

Learn to recognize, manage, and prevent the two common forms of this disease.

HOSPITAL-ACQUIRED pneumonia (HAP), the most common hospital-acquired infection following urinary tract infection, costs about $1.3 billion annually in hospital charges. Developing several days after hospital admission, HAP can double or triple a patients hospital stay. Most cases of HAP, which kills up to 55% of its victims, are associated with mechanical ventilation, but it also can be caused by aspiration. In this article, I'll focus on ventilator-acquired pneumonia (VAP). For more on aspiration pneumonia, see A Glance at Aspiration Pneumonia.

Who's vulnerable?

Patients at risk for HAP include the very elderly, smokers, and those with chronic lung disease or any severe illness or injury, such as severe head trauma, chest trauma, or shock. Other risk factors include diabetes, alcoholism, malnutrition, history of antibiotic or corticosteroid use, decreased level of consciousness, immunosuppression, poor oral hygiene, and elevated gastric pH.

Interventions that raise the risk of HAP include endotracheal (ET) or nasogastric (NG) intubation, enteral feedings, mechanical ventilation, sedation, changing ventilator tubing more often than every 48 hours, interrupting a closed suction system, use of histamine blockers or antacids, aerosol administration via in-line nebulizer, supine positioning, and head, thoracic, or upper abdominal surgery. Poor hand hygiene by staff is another contributing factor.

Passing the bug

In a healthy person, the body's own flora help prevent virulent pathogens from colonizing the oropharynx. But if your patients pulmonary defenses weaken, virulent pathogens can enter her lower respiratory tract via the oropharynx, multiplying rapidly to create infection and impair gas exchange. Normally alveolar macrophages would then stimulate the inflammatory response, sending systemic phagocytic cells to the infection site. When local or systemic defenses are overwhelmed, the infection can blossom into pneumonia. Signs and symptoms include:

* chest pain

* shortness of breath

* wheezing and crackles

* increased respiratory rate

* infiltrates on chest X-ray

* fever greater than 100.4° F (38° C)

* worsening gas exchange and hypoxemia

* elevated leukocyte count

* purulent tracheobronchial secretions

* dullness to percussion over affected lung areas, with egophony and bronchial breath sounds

* altered mental status.

When a ventilator is involved

Be alert for signs and symptoms of VAP in any patient receiving ventilator support. The risk of VAP increases with each day a patient is intubated and mechanically ventilated. Often difficult to diagnose, VAP may produce radiologic evidence of a new or progressive pulmonary infiltrate, leukocytosis, a suggestive Gram's stain, and bacterial growth in cultures of sputum, tracheal aspirate, pleural fluid, or blood.

Pneumonia that develops during the first few days of mechanical ventilation, called early-onset VAP, is typically caused by Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis. If VAP develops 5 or more days after mechanical ventilation starts, it's considered late-onset VAP; likely culprits include Pseudomonas aeruginosa, Acinetobacter, Enterobacter, or methicillin-resistant Staphylococcus aureus.

Suppose you're caring for Ms. Trapp, 47, who had a colectomy for colon cancer 5 days ago. She was extubated in the postanesthesia care unit and admitted to your surgical unit. Early today, she became unresponsive to painful stimuli, with snoring respirations, tachypnea, and an SpO^sub 2^ of 74% despite receiving 6 liters of oxygen via nasal cannula. At first suspecting oversedation from the opioid analgesic, her health care provider ordered two 0.1-mg doses of intravenous (I.V.) naloxone. When she remained unresponsive with depressed, shallow respirations and an SpO^sub 2^ of 80%, he transferred her to the intensive care unit (ICU).

On arrival in the ICU, Ms. Trapp's vital signs include fever of 102.4° F (39.1° C); pulse, 114; respirations, 26; and BP, 144/78. Her health care provider orders blood, urine, and sputum cultures; complete blood cell count with differential; electrolyte panel; serum creatinine level; liver function tests; a stat chest X-ray; computed tomography scan of the brain; and placement of a central venous catheter.

After being intubated, she's placed on synchronous intermittent ventilation and positive end-expiratory pressure. She's also put on N.P.O. status, and an NG tube is inserted and connected to low intermittent suction. She begins receiving I.V. fluids and I.V. piperacillin/tazobactam (Zosyn) and becomes responsive.

Her chest X-ray reveals proper ET tube placement, but also new bilateral lower lobe infiltrates. When you suction her, you note thick sputum that's tan to yellow and moderately blood-tinged. She responds to suctioning with a weak, ineffective cough.

You assess her respiratory status, including oxygen saturation, whether she breathes in synchrony with the ventilator, any use of accessory muscles or continued dyspnea, and signs of hypoxemia. If she's already developed pulmonary consolidation (the loss of pulmonary elasticity and filling of alveoli with infectious exudate), you may auscultate fine, inspiratory crackles or bronchial breath sounds.

Remember that Ms. Trapp's peak and plateau ventilator pressures will increase to reflect her altered dynamic compliance. Look for trends and discuss them with her respiratory therapist and pulmonologist in case her ventilator orders need modifying.

Sedation may be used to decrease oxygenation demands and improve ventilation, but you'll need to monitor your patient closely. Too much sedation could delay weaning from the ventilator later on.

Monitor Ms. Trapp's vital signs, oxygen saturation, and level of consciousness. Assess her for improved breath sounds and minute ventilation, increased dynamic compliance, and decreasing oxygenation requirements with ventilator changes. Watch for coughing when you suction her and note changes in sputum characteristics. Check her white blood cell trends and improvements in her chest X-ray results.

Ventilator-related contamination routes

One way a patient can acquire VAP is through accidental inoculation of her artificial airway with secretions that have pooled above the inflated ET tube cuff. Such secretions can easily migrate into her lower respiratory tract.

Ms. Trapp's weak cough probably won't protect her lower airway from aspiration of pooled oropharyngeal secretions. She might be better off with an ET tube that has a separate dorsal lumen, so subglottic secretions can be suctioned continuously.

Meticulously and consistently clean and store Ms. Trapp's bedside resuscitative bag-valve equipment to protect it from contamination with bacteria such as Pseudomonas. Replace the bag, per your facility's protocol, and discard it when Ms. Trapp no longer needs it. Microorganisms left in reusable bags may be aerosolized or sprayed into the patient's lower respiratory tract, creating infection.

Bacteria from your patients oropharynx can contaminate tubing and condensate within hours. Always wear gloves when emptying condensation, wash your hands thoroughly afterward, and wash your hands between patients. Contaminated condensation from the ventilator circuit can easily spill when you turn your patient. If your hospital uses condensation drainage traps, make sure they're checked and emptied properly.

Another source of contamination is the repeated use of small-volume medication nebulizers without proper cleaning and storage between uses. They can produce bacterial aerosols that bypass many of your patient's normal defenses against infection. While gloved, clean the nebulizer according to your hospital's protocol. Rinse it with sterile water rather than tap water, which can be a source of Legionella infections. Keep it in a covered container. Ask the respiratory therapist about using metered-dose inhalers instead of the nebulizer.

Avoid the risky practice of routinely repositioning Ms. Trapp's ET tube from one side of her mouth to the other while the cuff is deflated. Reposition only if you see that the oral mucosa is becoming ischemic from the pressure of the tube. Suction her only when indicated and avoid instilling sterile saline boluses. Use in-line suction catheters to prevent interrupting the closed system. Change the in-line suction catheter once a week or according to your facility's protocol.

Be sure to provide meticulous oral care. Assess your patients mouth daily and administer oral care every 2 to 4 hours if she's unconscious or intubated. Use a soft suction toothbrush at least twice daily. Foam swabs can be used to stimulate the oral mucosa between brushing, but avoid lemon swabs, which can be drying.

Ongoing care

Confirm the placement of Ms. Trapp's NG tube and keep it on low, intermittent suction to prevent gastric distension. Ms. Trapp is receiving sucralfate to prevent gastric ulceration. Auscultate her bowel sounds frequently and talk with her health care provider about when enteral nutrition can be resumed. Essential nutrients will speed her recovery, and enteral feedings may help to prevent bacterial migration.

Keep the head of the bed at 30 to 45 degrees when a feeding is provided; stop the feeding for at least an hour if the patient is to be placed supine.

Ms. Trapp's sputum sample reveals the infecting culprits: moderate Klebsiella pneumoniae and Proteus mirabilis, which are sensitive to Zosyn. A common therapy for pneumonia is Zosyn and a fluoroquinolone such as levofloxacin. But because this combination can cause nausea and vomiting, monitor her tolerance of enteral feedings closely. Adjust her antibiotic dosage if her blood urea nitrogen and serum creatinine clearance show renal impairment.

The combination of antibiotics and hospitalization puts Ms. Trapp at risk for diarrhea from development of a superinfection, such as pseudomembranous colitis. If she develops diarrhea, send stool cultures and follow standard and contact precautions.

The part of Ms. Trapp's lung affected by pneumonia is poorly ventilated because of underlying consolidation with a compensatory hypoxic vasoconstriction. Because this vasoconstriction impedes the delivery of antibiotics, most patients receive at least 5 days worth of antibiotics, but some require up to 3 weeks of I.V. therapy, depending on their clinical response.

Ms. Trapp's I.V. antibiotics will be discontinued as soon as possible after her temperature, respiratory rate, and oxygenation normalize; her breath sounds improve; and her secretions decrease.

Monitor the patient for improving clinical status and chest X-rays, but you probably won't see marked improvements for the first 48 to 72 hours of therapy.

If Ms. Trapp doesn't respond to treatment, her health care provider may order a different antibiotic regimen or another sputum culture, using fiber-optic bronchoscopy to obtain lower respiratory tract secretions. If she undergoes bronchoscopy, monitor her airway pressures, respiratory rate, and oxygen saturation closely; assess her frequently for fresh bloody secretions after the procedure.

Dealing with complications

Hospital-acquired pneumonia can lead to lung abscess, pulmonary necrosis, acute respiratory distress syndrome, and multiple organ dysfunction syndrome. If your patient has a pleural effusion, she may need a thoracentesis to drain the fluid, improve clinical signs and symptoms, and obtain specimens for lab analysis. Monitor her vital signs frequently after the procedure, assess for respiratory distress, and check the aspiration site for signs of infection.

Fortunately, Ms. Trapp's pneumonia resolves and she begins to improve. Soon, her ET tube is removed and she can resume eating. Encourage her to use incentive spirometry and to cough up her secretions.

She'll go home on oral levofloxacin. Before her discharge, teach Ms. Trapp and her family the signs and symptoms of pneumonia, how to administer her medications, adverse reactions to watch for, and when to call her primary care provider. Also teach her and her family about proper hand hygiene and mouth care. (She may need a dental appointment.)

By recognizing risk factors up front, you can prevent many cases of HAP. If HAP develops despite your best efforts, your nursing care and education can help your patient recover and avoid more complications.

SELECTED REFERENCES

Brooks, J.: "Postoperative Nosocomial Pneumonia: Nurse-Sensitive Issues," AACN Clinical Issues. 12(2):305-323, May 2001.

Fabian, T.: "Empiric Therapy for Pneumonia in the Surgical Intensive Care Unit," American Journal of Surgery. 179(Suppl., 2A):18S-25S, February 2000.

Grossman, R., and Fein, A.: "Evidence-Based Assessment of Diagnostic Tests for VAP," Chest. 117(4, Suppl., 2):177S-181S, April 2000.

Hixson, S., et al.: "Nursing Strategies to Prevent Ventilator-Associated Pneumonia," AACN Clinical Issues. 9(1):79-90, February 1998.

Schleder, B.: "Taking Charge of Ventilator-Associated Pneumonia," Nursing Management. 34(8):27-32, August 2003.

BY MARY "RANDE" DENT, RN, CCRN, CNS

Mary "Rande" Dent is a clinical nurse specialist in critical care at Holy Cross Hospital in Silver Spring, Md.

Copyright Springhouse Corporation Feb 2004
Provided by ProQuest Information and Learning Company. All rights Reserved