Miami Valley Hospital performed a mechanical ventilation benchmarking program to determine preweaning and weaning outcomes

Book Review, by Paul Mathews, PhD, RRT, FCCM, FCCP

As a means to continually be cost-effective with quality assured, Miami Valley Hospital (MVH), Dayton, Ohio, chose to embark on a means to not only shorten hospital stays, “Time to Trach,” and time to transfer to an extended care facility (ECF), but also to allow for better quality communication between all allied health care practitioners working on the client’s progress.

As a result, the Hospital Continuum of Care Committee suggested that this area be slated for a benchmarking study. A Mechanical Ventilation Benchmarking Program Committee involving key players from each area of health care involved in mechanical ventilation convened in 1997 and after much planning, education on the program guidelines began in 1998 for all shifts. The study was implemented for 90 days starting on November 30, 1998 to examine the processes for clients requiring mechanical ventilation.

A daily checkoff care flow sheet was designed to document ventilator management, nutrition, activity progression, rest, calm, and comfort. A continuum of care sheet allowed for documentation of procedures (bronchoscopy, tracheostomy placement/plugging/removal, percutaneous endoscopic gastrostomy placement, feeding tube placement, specialty bed, foley insertion/removal, swallowing evaluation, deep venous thrombosis surveillance) and interdisciplinary updates. The nature and scope of the committee was to standardize and improve quality care among all involved with the client’s care.

MVH chose to expand on the work of the National Study Group of the American Association of Critical Care Nurses¹ in the areas of mechanical-ventilation preweaning, weaning, and weaning outcomes. Knobel² described this model; Burns³ described a specific assessment tool called the Burns Weaning Assessment Program. The American Association for Respiratory Care published an entire manual on the topic of weaning protocols.⁴

A committee convened by the Hospital Continuum of Care Committee examined the processes of care for clients requiring mechanical ventilation. James Murphy, MD, director of the Critical Care/Pulmonary Medicine Department at MVH, chaired the committee. Amy Cline, RRT, director of respiratory services at MVH, served as a member and consultant. This group created the following protocol.

The Benchmarking Mechanical Ventilation Program (BMVP) service begins on the first day of intubation at MVH. Like the Knobel model, the protocol is phase directed, covering preweaning, weaning, and postweaning phases. Its sections include respiratory/airway progression; hemodynamics, including a bronchodilator protocol; nutrition and elimination; activity, rest, and comfort; psychosocial aspects of care, teaching, and discharge planning; continuity of care; and interdisciplinary condition updates.

A 1998-1999 pilot study enabled MVH to analyze tracheostomy demographics. For example, the investigators found that MVH has 100 to 110 tracheostomy patients per year; their mean age is 55 years, and they are released primarily to skilled nursing facilities. The benchmarking study also provided MVH with data on lengths of stay, costs of care, mortality rates, and readmission rates.

The goals set prior to the study were to reduce self-extubations and ventilator-associated pneumonia cases, to reduce the number of ventilator hours, to reduce the number of days that patients spent in bed before mobilization after intubation, to reduce the number of days that elapsed between intubation and physical therapy/occupational therapy consultation, to increase the number of patients receiving uninterrupted sleep, and to decrease the time that elapsed between intubation and tracheostomy.

MVH has achieved success in meeting these goals for several reasons. The majority of MVH clients do not require weaning from mechanical ventilation. MVH is a major trauma center for its area; depending on the cause of intubation, the patient may simply need ventilatory support to be removed in an expeditious fashion, with no gradual weaning necessary. The medical members of the Mechanical Ventilation Benchmarking Program Committee determined that the key factor in successful extubations of this type is recognizing when the patient is ready. This time has usually been reached when the underlying reason for mechanical support has been corrected.

Criteria were set by the committee to help MVH staff to decide whether a given client was ready for weaning. RCPs provide the necessary measurements; if the weaning criteria are met, the patient is ready for a 2-hour trial of continuous positive airway pressure (CPAP) therapy. If CPAP is not tolerated, the patient is returned to use of the pretrial form of ventilatory support.

Weaning consists of retraining the respiratory muscles. The weaning program should be individualized to accommodate the individual’s diagnosis and tolerance. The client is allowed to undergo weaning to point of fatigue (but not to become overly fatigued). Physical therapists know this concept well; the respiratory muscles do not differ from other muscles in their response to fatigue. Specific weaning protocols were designed by the in-house committee.

Standard physician-order sheets (Figure 1) provide initial ventilation orders and client parameters. RCPs complete screening to meet weaning criteria by 7 am daily. If the client meets the criteria, the physician is notified that orders are needed. If weaning criteria are not met, physicians can opt for synchronized intermittent mandatory ventilation (SIMV) with pressure support, pressure-support ventilation (PSV), or T-piece/CPAP options.

Figure 1. Advanced care mechanical ventilation physician’s order sheet.

Preferred weaning hours are 8 am to 9 pm. If PSV and SIMV are used, airway resistance is reevaluated every morning and settings are adjusted accordingly. The mandatory breathing rate is gradually lowered to four breaths per minute. If the client is using positive end-expiratory pressure (PEEP), the change is continued as CPAP on spontaneous respiration. If signs of intolerance are observed, the previous ventilator settings are reinstated (or, if needed, higher settings are used).

With PSV, a tidal volume of 5 to 7 mL/kg should be maintained, along with a respiratory rate that is comfortable for the client. Pressure may be decreased systematically by 3 to 5 cm H2O once per shift if tolerated as long as the client’s spontaneous respiratory rate remains within the safe range. Pressure should be decreased until it equals airway resistance. At this time, the physician can be called for an extubation order. Again, if signs of intolerance begin to show, the client should return to using the previous (or higher) ventilator settings.

If the T-piece/CPAP mode is chosen, the fraction of inspired oxygen (Fio2) will be equal to, or 10% greater than, the baseline level. CPAP will be set to equal the PEEP level. Respiratory vital signs will be assessed 10 to 15 minutes after this change is instituted.

Figure 2. Mechanical ventilation physician’s supplemental order set sheet.

If the client is stable enough to move to a step-down unit (Figure 2, page 56), SIMV with PSV will be used starting the day after the transfer. PSV will be set to equal airway resistance and Fio2 will be decreased to the lowest possible level required by that patient, based on his/her individual needs. PEEP should be set at less than 5 cm H2O. The SIMV rate will be decreased by one breath per minute per day until the client reaches an SIMV rate of four breaths per minute. It will then be changed to both CPAP and PSV, with pressure decreased by 2 to 4 cm H2O each day until it equals airway resistance.

Nonpharmacological intervention should be considered first for pain and sedation when weaning mechanically ventilated clients. Noise control, sleep deprivation, limitation of drugs (benzodiazepines), and lorazepam or morphine may be used for pain and sedation. The physician should be notified if other options do not work; propofol may be useful in trauma cases. A pharmacist is constantly available for consultation with weaning-program staff.

If lorazepam is used, escalating doses should be prescribed. Its onset of action may take place 15 to 20 minutes after its administration, so 1 to 5 mg every 15 minutes for four doses may be required. Its duration of action is 1 to 4 hours, so hyperdynamic clients (such as those with trauma or sepsis) may clear the drug more quickly and elderly patients may clear it more slowly.

If clients require more sedation while receiving continuous infusions of lorazepam, additional bolus doses can be given. The infusion rate of 1 mg per hour may also need to be increased if boluses have been given more frequently than every 1 to 2 hours. The infusion rate should not, however, be increased more than once every 6 hours, so that the maximal effect of the changed infusion rate will be evident. It should be remembered that hypotension can occur if the rate of infusion is too high. Boluses should be infused at a rate no more rapid than 2 mg per minute.

A separate mechanical ventilation flow sheet is provided for use in care documentation by RCPs and nurses. RCPs are to complete screenings for weaning criteria and document their results. The team (consisting of RTs, physicians, nurses, occupational therapists, physical therapists, dieticians, pharmacists, and social workers) determines a goal for the day by evaluating the patient’s weaning candidacy. Goals for pH, Pco2, and pulse-oximetry oxygen saturation (Spo2) should be obtained from the physician’s orders. Baseline Spo2 values may be obtained from previous medical records. The client’s nutrition should be documented, including the rate of feedings or total parenteral nutrition and whether nutritional goals have been met. Use of the aspiration-screening tool should also be included daily and dieticians should monitor for level of consciousness and excessive oral secretions.

The MVH activity progression guideline provides direction for all professionals involved in the client’s care. It consists of five levels; the client should progress to the highest achievable state, from bed rest through head-of-bed elevation through sitting on the side of the bed with the legs dangling and being out of bed in a stretcher chair through bearing his or her own weight in transferring to a canvas wheelchair to fully ambulatory status. The guidelines direct nurses to obtain occupational and physical therapy consultations. Canvas wheelchairs are used in step four because they have more back support and are higher than the chairs found in clients’ rooms. The wheelchairs are to remain available to clients, and occupational or physical therapy staff members who work with the devices are asked to document their use to ensure safety for the next health care worker who comes on the following shift. The use of an individualized activity schedule is encouraged. Continuous sleep lasting at least 4 hours per night is also encouraged, and a nap is recommended during the day. If the client becomes agitated, caregivers should be sure to document the timing and cause of the episode. The continuum of care and interdisciplinary condition update sheet used at MVH provides a weekly summary of the client’s progress toward his or her goals.

Conclusion
After 1 year, the length of stay did not change; however, the time to implement physical therapy, occupational therapy, and feeding regimens did improve greatly upon initial evaluation. “Time to trach” did not change as significantly as the hospital had anticipated due to differences of opinion.

Since the study was targeted to nontrauma patients, the prospective trauma population is now being considered for study to find out if length of stay and costs could be significantly impacted by this population. The number of ventilators run 30 to 35 per day on average and reach as high as 60 in peak months.

The entire MVH respiratory team consists of approximately 150 employees, of whom 110 are involved with adult care and there are 60 employees directly involved with the benchmarking initiative.

Kim Cathcart, MSedA, RN, RRT, is primary care nurse and per diem respiratory care practitioner at Med/Surg Health Center, Miami Valley Hospital, Dayton, Ohio.

References
1. Milliner MP. Ventilator weaning protocols: a comparison study. RT. 2000;13(1):29-32.
2. Knobel A. Weaning from mechanical ventilatory support: a refinement of a model. Am J Crit Care. 1998;7:149-152.
3. Burns S. Burns Weaning Assessment Program (BWAP). Am J Crit Care. 1994;3:12-13.
4. Morris T. Managed care’s impact on academic centers’ research programs. RT. 1999;12:65-68.