Vol. 10 •Issue 9 • Page 18
Weaning Protocol Works in Long-Term Care Setting ventilation today
By Audrey Liu, MD, Karen Goodison, RRT, and Jonathan E. Sevransky, MD
The Ventilator Rehabilitation Unit at Johns Hopkins Bayview Medical Center, Baltimore, was initially intended to treat ventilator-dependent patients. Typically, these patients had survived an acute illness requiring intensive care unit admission but were unable to be extubated, due either to underlying disease or the severity of the illness.
After two to three weeks of intubation, they would undergo tracheostomy. If further attempts at weaning were unsuccessful, and they no longer required .inpatient hospitalization, they would be transferred to the Ventilator Rehabilitation Unit for ongoing ventilator management and treatment, without the costs and risks (e.g. nosocomial infection) of inpatient care.1,2
Somewhat to the surprise of the staff, however, some transferred patients thought to be ventilator- dependent were eventually liberated from the .ventilator. After one such case, the medical and respiratory staff agreed that a systematic approach to withdrawing mechanical ventilatory support should be implemented.
Taking a cue from the acute care setting, where a systematic respiratory therapy-driven weaning .protocol had been shown to improve the likelihood that a patient could be rapidly liberated from the ventilator,3,4 the Johns Hopkins Geriatrics Center staff wrote a weaning protocol for the Ventilator Rehabilitation Unit.
Traditionally, physicians determined the appropriate time to initiate attempts to discontinue ventilatory support. However, there were wide variations in practice among them regarding the aggressiveness and modes of weaning. Studies in the ICU have shown that physician-directed weaning attempts are often delayed and that a multi-disciplinary approach involving respiratory therapy, nursing and pulmonology can standardize care, reduce costs and improve patient outcomes.3,4 Given the relative .infrequency of physician visits and the consistent .respiratory presence in the .geriatrics center, we believed that the long-term care setting was ideal for such a .multi-disciplinary approach.
DEVELOPING THE PROTOCOL
In developing the protocol, the geriatrics, pulmonary, and respiratory therapy divisions used a decision tree. They also developed a weaning assessment flowsheet to assist the respiratory therapist in weaning and ensure consistency. Because the data in the acute care setting supported the use of T-piece weaning, they based the long-term care setting’s protocol on a similar approach.
One change from the acute care setting was that the speed of the weaning process was modified. In the acute care hospital, most patients who are tested for the ability to wean can be rapidly liberated from the ventilator.5-7 Patients with chronic respiratory failure often have nutritional and muscular deficits that may need to be corrected prior to liberation. Further, most have failed multiple attempts at weaning prior to their admission to the ventilator unit. We therefore took a more measured strategy.
Training the staff was the next step after the protocol was developed. Because most respiratory therapists had been employed on the unit for an extended period of time and had nurtured the protocol process, there wasn’t a concern about them “buying into” it. However, to effectively implement it, the medical, nursing and respiratory therapy staff participated in a series of in-services.
BEGINNING THE PROCESS
The initial steps of the protocol involve a weaning assessment within the first 48 hours of patient admission. Patients must have stable vital signs and no symptoms of cardiac disease in order to initiate the passive part of the study. In addition, they need to be on an FIO2 of ² 0.5 and ² 5 cm of positive end-expiratory pressure. While we would desire to have a peak pressure ² 50 and a plateau pressure ² 30 cm of water, if the other parameters are adequate, the weaning protocol is continued even if they do not meet the pressure criteria.
Physiologic parameters assessed include .negative inspiratory force, minute ventilation, respiratory rate and heart rate. Oxygen saturation and end tidal CO2 levels also are measured. If a patient has a negative inspiratory pressure, the absolute value of which is greater than Ð20 cm of water, a spontaneous respiratory rate of less than 35 breaths per minute and spontaneous tidal volumes of more than 250 ml, the patient passes the passive airway study and starts weaning attempts.
The first attempt at weaning involves a T-piece wean of 15 minutes. The respiratory therapist remains at the bedside and continuously monitors the patient’s end-tidal CO2, oxygen saturation and vital signs. The second and subsequent attempts involve doubling the weaning duration. If a patient fails a weaning attempt, they are placed on full ventilatory support for 24 hours to rest, and then the process is restarted. (See Figure 1, page 18.) The protocol includes continued weekly testing of patients who do not pass the initial screen. If three consecutive screens are failed, we switch to monthly testing.
Most patients admitted to the ventilator unit are diagnosed with underlying pulmonary disease; chronic obstructive pulmonary disease is the most common diagnosis. However, patients with neuromuscular disorders, respiratory failure after traumatic injury, surgery and sepsis also are admitted. Most of the patients have severe malnutrition, decreased lean .muscle mass and weakness. On the unit, a multidisciplinary team including geriatricians, pulmonologists, respiratory .therapists, nutritionists and physical and .occupational therapists participate in the patients’ care.
Several patients who initially have not been able to tolerate weaning have successfully weaned after nutritional support and physical therapy. A good example is a 79-year-old woman who developed respiratory failure after lobectomy for lung cancer. Although she initially did not tolerate weaning, after a nine-month stay she began to .tolerate brief periods off the ventilator. By the 11th month of her admission, she had been liberated from the ventilator, and she is currently undergoing tracheostomy care training toward being discharged home.
One of the key issues in developing and modifying the screening process is the assurance of patient safety during weaning. Toward this goal, two dedicated therapists are present on each wing. In addition, a four-bed observation room allows for closer monitoring of recent admissions, patients who are actively weaning or those who have been recently decannulated. We also have the ability to continuously monitor pulse oximetry and capnography for select patients.
Prior to having the weaning protocol in place, only a small percentage of patients admitted into the geriatrics center were ventilator-liberated. In 1998, just prior to implementation of the protocol, five of 39 patients (13 percent) were weaned off ventilatory .support. In the 22 months since implementation, 22 of 89 patients (25 percent) admitted were successfully liberated, resulting in the name of the unit being changed from the Chronic Ventilator Unit to the Ventilator Rehabilitation Unit.
Of course, not all patients admitted to the geriatrics center are likely weaning candidates. Forty percent have irreversible diseases such as ALS, brain stem hemorrhage or other disease processes that make them unlikely to wean.
The success of this protocol depends on collaboration among the different disciplines at the center. While physician input is necessary to initiate the protocol for unusual cases, weaning attempts may proceed without their involvement at every stage. Further, the protocol is regularly reviewed by all of the team members involved to assure that the goals of safe weaning are being met.
Given the aging of the population and the increasing number of patients .discharged from the hospital on ventilatory support,8 it’s likely that the number of patients with chronic respiratory failure will continue to increase. In our unit, the number of ventilator beds has increased from 12 in 1997, to 19 in 1999, to 27 in 2001.
Currently, we are analyzing our records to see whether we can better predict which patients with chronic respiratory failure are likely to be liberated from the ventilator. We are also exploring earlier admission of appropriate patients from the intensive care and step-down units of two affiliated medical centers to allow for use of this .protocol.
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2. Seneff MG, Wagner DW, Thompson D, Honeycutt C, Silver MR, et al. The impact of long-term acute-care facilities on the outcome and cost of care for patients undergoing prolonged mechanical ventilation. Crit Care Med. 2000;28:342-50.
3. Ely EW, Baker AM, Dunagan DP, Burke HL, Smith AC, Kelly PT, et al. Effect of the duration of mechanical ventilation of identifying patients capable of breathing spontaneously. N Engl J Med. 1996;335:1864-9.
4. Kollef MH, Shapiro SD, Silver P, St. John RE, Prentice D, Sauer S, et al. A randomized, controlled trial of protocol-directed vs. physician-directed weaning from mechanical ventilation. Crit Care Med. 1997;25(4):567-74.
5. Esteban A, Frutus F, Tobin MJ, Alia I, Solsaan JF, Valverdu V, et al. A comparison of four methods of weaning patients from mechanical ventilation. N Engl J Med. 1995;332:345-50.
6. Yang K, Tobin M. A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation. N Engl J Med. 1991;.324:1445-1450.
7. Brochard L, Rauss A, Benito S, Conti G, Manebo J, Rekik N, et al. Comparison of three methods of gradual withdrawal from ventilatory support during weaning from mechanical ventilation [abstract]. Am J Respir Crit Care Med. 1994;150:896-903.
8. Montuclard L, Garrouste-Orgeas M, Timist JF, Misset B, DeJonghe B, Carlet J, et al. Outcome, functional autonomy and quality of life of elderly patients with a long term-intensive care unit stay. Crit Care Med. 2000;28:3389-3396.
The authors work at Johns Hopkins University School of Medicine, Baltimore. Dr. Liu is with the department of medicine, Goodison is with the division of respiratory therapy, and Dr. Sevransky is with the division of pulmonary and critical care medicine.