Successful weaning from mechanical ventilation. Strategies to avoid failure

Cardiovascular surgery patients' respiratory responses to morphine before extubation

Analgesia is commonly withheld from cardiovascular surgery patients who are soon to be withdrawn from mechanical ventilation to prevent respiratory depression that can postpone extubation. The effects of analgesia on respiration have not been studied adequately. In this study, weaning parameter measurements were obtained to determine the respiratory impact of a low dose of intravenous morphine administered to cardiovascular surgery patients who were ready to be weaned from the ventilator. A pretest-posttest, quasi-experimental, repeated measures design was used. Eleven alert patients who experienced postoperative pain and met two of five weaning parameter criteria received 1 mg to 5 mg of morphine. Weaning parameters were measured before the intervention and at 15 and 30 minutes afterward. As hypothesized, the administration of low-dose morphine did not have a negative effect on weaning parameters. Mean weaning parameter values either increased or remained the same after the administration of morphine. Despite the small sample size, the results of dependent t tests revealed statistically significant improvements, using an alpha level of 0.05, in the mean tidal volume and negative inspiratory force values at the 30-minute measurement, and in the vital capacity value at the 15-minute measurement. The findings from this study help to refute the notion that a low dose of intravenous morphine will cause respiratory depression, and further suggest that the administration of morphine may enhance patients' respiratory function. If additional research supports this study's findings, both the goals of weaning postoperative patients from the ventilator and controlling pain may be achieved simultaneously.

Qualitative analysis of patients' work during mechanical ventilation and weaning

OBJECTIVE

To describe patients' recollections of their experiences during mechanical ventilation and weaning and to extend an evolving nursing theory of weaning.

DESIGN

A qualitative approach that used grounded theory techniques.

PATIENTS AND METHODS

We surveyed 20 hospitalized patients who had recently undergone mechanical ventilation and weaning from the ventilator in a critical care unit. Included in the analysis were any thoughts, feelings, or actions recalled by the patients that were related to the weaning experience.

RESULTS

During ventilation and weaning, patients were engaged to various degrees in what they called "work," which consisted of their efforts to assist in their adjustment and recovery. This work had four themes: sense making, enduring, preserving self, and controlling responses. These themes represented activities by which patients dealt with their personal concerns and cooperated with the therapeutic plan.

CONCLUSIONS

Despite good care during the process, mechanical ventilation and weaning are stressful experiences that require active participation by patients. Patients' work needs to be understood and supported by clinicians to facilitate recovery from mechanical ventilation and weaning.

Two methods of weaning persons with quadriplegia from mechanical ventilators

Two commonly-used methods of weaning individuals with quadriplegia from mechanical ventilators were compared. The medical records were reviewed of 52 patients who were injured at the C3 or C4 levels, were ventilator dependent following their injury, and were treated at the participating facilities. The study subjects had a total of 82 separate wean attempts: 26 utilized intermittent mandatory ventilation, 34 used progressive ventilator-free breathing (T-piece weaning) and 22 used either a combination of these approaches or a different approach. With an overall weaning success rate of 83%, this study demonstrated that individuals with C3 and C4 quadriplegia are indeed candidates for ventilator weaning. Comparing the two weaning methods, progressive ventilator-free breathing was found to be successful more often than intermittent mandatory ventilation (67.6% compared to 34.6%). In addition, progressive ventilator-free breathing appeared superior in its ability to provide a more functional alternative to individuals unable to wean completely.

The noninvasive respiratory care unit. Patterns of use and financial implications

Clinical, socioeconomic, and ethical dilemmas have prompted reevaluation of traditional methods of providing intensive care. Six years ago, we established a noninvasive respiratory care unit (NRCU) for selected patients in need of intensive respiratory monitoring and therapy, particularly those requiring prolonged mechanical ventilation. One impetus for the formation of the NRCU was the expectation that it might prove to be a less costly alternative to the intensive care unit (ICU) for selected patients. We reviewed data from all patients admitted to the NRCU from July 1, 1987 through June 30, 1988 to identify characteristics of the patient population and to evaluate potential cost savings. During one year of operation, 136 patients were admitted to the unit, 107 of whom were mechanically ventilated. Overall, hospital costs for these patients exceeded payments by $1,519,477. Losses were greatest for mechanically ventilated patients and those for whom Medicare or Medicaid were the primary payors. Daily costs of care for mechanically ventilated patients were $1,976 lower in the NRCU than in the medical intensive care unit (MICU). We conclude that the NRCU represents a cost-effective approach to the care of substantial numbers of patients requiring specialized respiratory care.