Outcomes in post-ICU mechanical ventilation: a therapist-implemented weaning protocol.

BACKGROUND: Therapist-implemented protocols have been used to extubate or wean patients in the ICU setting. Barlow Respiratory Hospital (BRH) functions as a center for weaning patients from prolonged mechanical ventilation (PMV) in the post-ICU setting of a long-term acute-care (LTAC) facility. A therapist-implemented patient-specific (TIPS) weaning protocol was developed at BRH to standardize weaning from PMV. STUDY DESIGN: Prospective cohort study with historical control. METHODS: A weaning protocol incorporating the procedures and pace of LTAC weaning was developed using available scientific evidence and expert consensus. After training of staff, collection and analysis of pilot data, and revisions and refinement of the protocol, the TIPS protocol was implemented hospital-wide. It was monitored for outcome, variance, and respiratory care practitioner (RCP) and physician compliance. RESULTS: Forty-six RCPs worked with eight pulmonologists treating 271 consecutive patients admitted for weaning from PMV during an 18-month period. Nineteen patients were excluded from weaning attempts by any method after initial physician evaluation. The remaining 252 patients (9,135 total ventilator days) were compared with a group of 238 patients treated by the same physicians in the 2 years before instituting protocol weaning. Median time to wean declined significantly from 29 days in historical control subjects to 17 days for TIPS protocol patients (p < 0.001). Outcomes (scored at discharge) were comparable for the two groups (TIPS group vs control group): weaned, 54.7% vs 58.4%; ventilator-dependent, 17.9% vs 10.9%; died, 27.4% vs 30.7% (p = 0.10). Variances incurred by physicians and RCPs were 324 and 136, respectively, for the 9,135 ventilator days. CONCLUSIONS: Patients weaned from PMV using a new therapist-implemented protocol at BRH, an LTAC facility specializing in weaning, had significantly shorter time to weaning than historical control subjects, with comparable outcomes. The weaning outcome data collected after the implementation of the TIPS protocol are in fact attributable to its use, as we found a high degree of compliance with the protocol.

Approach to patients with long-term weaning failure.

Efforts to treat reversible disease processes that contribute to ventilator dependency in the intensive care unit (ICU) fail in up to 20% of patients, resulting in prolonged mechanical ventilation (PMV). Resolution of the insults that necessitated ICU admission and mechanical ventilation may be incomplete, and the economic pressure to transfer patients is ever increasing. The choice of post-ICU disposition depends on the patient's clinical condition, the resources of the transfer destination, and whether weaning attempts will continue. This article reviews data from a decade of weaning beyond the ICU, including outcomes of more than 2700 patients with PMV afforded continued attempts at liberation in long-term acute care facilities and other post-ICU weaning venues. Assessment and treatment, weaning strategies, and complications of patients with PMV are described.

Provision of long-term mechanical ventilation.

When patients suffer prolonged mechanical ventilation, physicians are faced with a series of decisions beginning in the intensive care unit (ICU) and extending into a broadening spectrum of post-ICU levels of care. This article reviews current thinking and outcome data on when and how to perform the tracheostomy, as well as when and where the patient should be transferred from the ICU for continued weaning efforts or support. Decannulation after success in weaning and continuation of ventilation at home are also addressed.

Patient-ventilator trigger asynchrony in prolonged mechanical ventilation.

STUDY OBJECTIVE: To investigate patient-ventilator trigger asynchrony (TA), its prevalence, physiologic basis, and clinical implications in patients requiring prolonged mechanical ventilation (PMV). STUDY DESIGN: Descriptive and prospective cohort study. SETTING: Barlow Respiratory Hospital (BRH), a regional weaning center. PATIENTS: Two hundred consecutive ventilator-dependent patients, transferred to BRH over an 18-month period for attempted weaning from PMV. METHODS AND INTERVENTIONS: Patients were assessed clinically for TA within the first week of hospital admission, or once they were in hemodynamically stable condition, by observation of uncoupling of accessory respiratory muscle efforts and onset of machine breaths. Patients were excluded if they had weaned by the time of assessment or if they never achieved hemodynamic stability. Ventilator mode was patient triggered, flow control, volume cycled, with a tidal volume of 7 to 10 mL/kg. Esophageal pressure (Peso), airway-opening pressure, and airflow were measured in patients with TA who consented to esophageal catheter insertion. Attempts to decrease TA in each patient included application of positive end-expiratory pressure (PEEP) stepwise to 10 cm H2O, flow triggering, and reduction of ventilator support in pressure support (PS) mode. Patients were followed up until hospital discharge, when outcomes were scored as weaned (defined as >7 days of ventilator independence), failed to wean, or died. RESULTS: Of the 200 patients screened, 26 were excluded and 19 were found to have TA. Patients with TA were older, carried the diagnosis of COPD more frequently, and had more severe hypercapnia than their counterparts without TA. Only 3 of 19 patients (16%), all with intermittent TA, weaned from mechanical ventilation, after 70, 72, and 108 days, respectively. This is in contrast to a weaning success rate of 57%, with a median (range) time to wean of 33 (3 to 182) days in patients without TA. Observation of uncoupling of accessory respiratory muscle movement and onset of machine breaths was accurate in identifying patients with TA, which was confirmed in all seven patients consenting to Peso monitoring. TA appeared to result from high auto-PEEP and severe pump failure. Adjusting trigger sensitivity and application of flow triggering were unsuccessful in eliminating TA; external PEEP improved but rarely led to elimination of TA that was transient in duration. Reduction of ventilator support in PS mode, with resultant increased respiratory pump output and lower tidal volumes, uniformly succeeded in eliminating TA. However, this approach imposed a fatiguing load on the respiratory muscles and was poorly tolerated. CONCLUSION: TA can be easily identified clinically, and when it occurs in the patient in stable condition with PMV, is associated with poor outcome.

Post-ICU mechanical ventilation: treatment of 1,123 patients at a regional weaning center.

STUDY OBJECTIVES: To update our database, reporting changes in the results of weaning attempts and profile of patients transferred to us after prolonged mechanical ventilation (PMV) in the ICU. DESIGN: Retrospective record review, with prospective recording of physiologic measurements on admission from mid-1994. SETTING: Regional weaning center (RWC). PATIENTS: We studied 1,123 consecutive ventilator-dependent patients transferred for attempted weaning over an 8-year period. MEASUREMENTS AND RESULTS: Median (range) time of mechanical ventilation prior to transfer to the RWC declined from 37 (1 to 249) days in 1988 to 29 (1 to 120) days in 1996 (p<0.05). Acute physiology score of acute physiology and chronic health evaluation (APACHE) III was 32 (6 to 123) on RWC admission, equaling reported scores soon after ICU admission. Comparing other data on admission from 1988 to 1996, mean (+/-SD) serum albumin level declined from 2.92+/-0.58 to 2.43+/-0.50 g/dL, and alveolar-arterial oxygen pressure difference widened from 106+/-50 to 139+/-99 mm Hg. Prevalence of stage II or worse pressure ulceration on admission increased from 34% in 1988 to 46% in 1995. Despite these trends, there has been no significant change in patient outcome (55.9% weaned, 15.6% failed to wean, 28.8% died) or in median time to wean (29 [1 to 226] days). Overall survival at 1 year after discharge for the 8-year period is 37.9%, improving from 29% in 1988-1991 to 45% since 1992; survival in weaned patients discharged to home has improved from 45 to 59% during the respective time periods. CONCLUSIONS: Patients are being transferred from the ICU to our RWC for attempted weaning sooner in their course of PMV. Although more severely ill on arrival than in past years, mortality is unchanged, more than half of the patients continue to be successfully weaned, and survival after RWC discharge is improved.

Impact of renal dysfunction on weaning from prolonged mechanical ventilation.

BACKGROUND: In the intensive care unit (ICU) setting, the combination of mechanical ventilation and renal replacement therapy (RRT) has been associated with prolonged length of hospital stay, high cost of care and poor outcome. We gathered outcome data on patients who had severe renal dysfunction on transfer to our regional weaning center (RWC) for attempted weaning from prolonged mechanical ventilation (PMV). We screened the admission laboratory values of 1077 patients transferred to our RWC over an 8-year period. We reviewed the medical records of patients with serum creatinine > 2.5 mg/dl. RESULTS: Sixty-three patients met screening criteria and 40 patients were on RRT at the time of transfer. Eighteen patients had begun chronic RRT at least 2 months prior to admission to the transferring hospital for their current illness. Twenty-two patients had RRT initiated at the transferring hospital. Ten patients had RRT initiated at the RWC; eight patients had improvement or resolution of azotemia at our facility. RRT was withheld at patient/family request in five patients with progressive renal failure. None of the 50 patients who received RRT recovered renal function during treatment at our RWC. Intermittent hemodialysis was the standard RRT at the RWC. Duration of mechanical ventilation prior to transfer to the RWC was 49.7 +/- 33.5 days (mean +/- SD).Outcome of weaning attempts in the 63 patients was as follows: 13% weaned, 3% failed to wean and 84% died. These outcomes were significantly worse (P<0.001) than those in the 1014 patients whose admission serum creatinine was