Effects of fiberoptic bronchoscopy during mechanical ventilation in a lung model.

STUDY OBJECTIVES: To evaluate the effects of fiberoptic bronchoscopy (FOB) on delivered volumes and pressures during mechanical ventilation, utilizing a lung model. DESIGN: Bench study. SETTING: Laboratory. MATERIALS AND METHODS: Using varying-sized endotracheal tubes (ETTs), we ventilated a lung model at two levels of compliance utilizing different modes and parameters of ventilation. After establishing baseline measurements, the bronchoscope was inserted and measurements repeated. MEASUREMENTS AND RESULTS: During controlled mechanical ventilation (CMV) with a preset high-pressure limit (HPL), tidal volumes (VTs) were reduced from 700 mL to 0 to 500 mL following insertion of the bronchoscope. Increasing the HPL to 120 cm H(2)O resulted in a VT of 40 to 680 mL. Changing from square to decelerating flow waveform resulted in no consistent difference in VT. Auto-positive end-expiratory pressure (auto-PEEP) of 0 to 41 cm H(2)O was present under most conditions. Higher rates and lower peak inspiratory flows were associated with higher levels of auto-PEEP. In the pressure-control (PC) mode, using a preset inspiratory pressure level (IP), VT was reduced from 700 mL to 40 to 280 mL following insertion of the bronchoscope. Maximum IP (100 cm H(2)O) increased VT to 260 to 700 mL. Auto-PEEP was less in the PC mode. CONCLUSIONS: Extreme care must be taken when bronchoscopy is performed on a patient receiving mechanical ventilation. Extremely low VT and significant auto-PEEP may develop unless flow, respiratory rate, mode, and ETT size are carefully selected. The PC mode delivered more volume than did the CMV mode. When performing FOB during mechanical ventilation, the inside diameter of the ETT should be > or = 2.0-mm larger than the outside diameter of the bronchoscope to maintain volume delivery and minimize the development of auto-PEEP.

A randomized, placebo-controlled study to evaluate the role of salmeterol in the in-hospital management of asthma.

STUDY OBJECTIVES: To assess the safety and efficacy of salmeterol xinafoate as an adjunct to conventional therapy for the in-hospital management of acute asthma. DESIGN: A prospective, double-blind, randomized placebo-controlled trial. SETTING: Medical wards of a large university-based hospital. PATIENTS: Forty-three patients admitted for an acute exacerbation of asthma. INTERVENTIONS: Salmeterol (42 microg) or two puffs of placebo every 12 h in addition to standard therapy (short-acting beta-agonists, corticosteroids, and anticholinergic agents). RESULTS: No clinically adverse effects were seen with the addition of salmeterol to conventional therapy. After salmeterol, there was no difference in pulse, respiratory rate, oxygen saturation by pulse oximetry, severity of symptoms, or dyspnea score. Patients receiving salmeterol had greater FEV(1) percent improvements than the placebo group at 12, 24, 36, and 48 h. These findings were not statistically significant. By paired Student's t tests, there were significant improvements in FEV(1) (p = 0.03) and FVC (p = 0.03) in the salmeterol group after 48 h of treatment with no comparable improvement in the placebo group. In a subgroup analysis of patients with an initial FEV(1) < or = 1.5 L, the absolute FEV(1) percent improvement for salmeterol vs placebo was 51% vs 16% at 24 h and 54% vs 40% at 48 h. The relative FEV(1) percent improvement for salmeterol vs placebo was 17% vs 8% at 24 h and 18% vs 14% at 48 h. CONCLUSION: The addition of salmeterol to conventional therapy is safe and may benefit hospitalized patients with asthma. Further studies are needed to clarify its role in the treatment of acute exacerbation of asthma.

A comparison of the effects of assist-control, SIMV, and SIMV with pressure support on ventilation, oxygen consumption, and ventilatory equivalent.

OBJECTIVE: To quantify the ventilatory efficiency of different modes of mechanical ventilation used to achieve full ventilatory support in normal subjects. Modes compared were assist-control, synchronized intermittent mandatory ventilation (SIMV), and SIMV with 10 cm H2O (0.98 kPA) of pressure support. DESIGN: Prospective, randomized blocks repeated measures design. Subjects served as their own controls. SETTING: A university affiliated pulmonary laboratory. SUBJECTS: Ten healthy volunteers, aged 31-54 years. OUTCOME MEASURES: Minute volume, respiratory rate, average tidal volume, oxygen consumption, and ventilatory equivalent. INTERVENTION: Baseline spontaneous ventilation data collection was followed by mechanical ventilation by mouthpiece in each of three modes in a random sequence. All modes used a machine set rate of 12 breaths per minute, VT of 10 cc/kg of ideal body weight, inspiratory time of 1 second, square wave flow pattern and a sensitivity of -1 cm H2O (-0.09806 kPa) to achieve full ventilatory support. Data were collected continuously for 5 minutes and the mean values were reported. Ventilatory equivalent for oxygen is a measure of the efficiency of the ventilatory pump at various work loads and was calculated by dividing VE (BTPS) by the VO2 (STPD). RESULTS: There were significant differences by mode of mechanical ventilation in average tidal volume (p = 0.02), minute volume (p = 0.02), oxygen consumption (p = 0.04), and ventilatory equivalent (p = 0.01) using ANOVA. There was no significant difference (p = 0.66) by mode of ventilation in respiratory rate. Pairwise follow-up comparisons for these variables found that SIMV with pressure support produced a significantly greater average tidal volume, minute volume, oxygen consumption, and ventilatory equivalent than SIMV alone. SIMV with pressure support also produced a significantly greater minute volume and ventilatory equivalent than assist-control. There were no significant differences between assist-control and SIMV. All three modes produced a lower ventilatory equivalent and higher oxygen consumption than spontaneous breathing. CONCLUSIONS: SIMV with pressure support significantly increased minute volume and ventilatory equivalent when compared with assist-control or SIMV alone, and thus was the most efficient mode of full ventilatory support for our subjects. We found no difference in ventilatory efficiency between assist-control and SIMV. All three mechanical modes were less efficient for our subjects than spontaneous breathing. The inspiratory time of 1 second used in this study, although common in clinical practice, may be inadequate for some patients.

Analysis of job satisfaction, burnout, and intent of respiratory care practitioners to leave the field or the job.

BACKGROUND: Increased stress, burnout, and lack of job satisfaction may contribute to a decline in work performance, absenteeism, and intent to leave one's job or field. We undertook to determine organizational, job-specific, and personal predictors of level of burnout among respiratory care practitioners (RCPs). We also examined the relationships among burnout, job satisfaction (JS), absenteeism, and RCPs' intent to leave their job or the field. METHODS: A pilot-tested assessment instrument was mailed to all active NBRC-credentialed RCPs in Georgia (n = 788). There were 458 usable returns (58% response rate). A random sample of 10% of the nonrespondents (n = 33) was then surveyed by telephone, and the results were compared to those of the mail respondents. Variables were compared to burnout and JS scores by correlational analysis, which was followed by stepwise multiple regression analyses to determine the ability of the independent variables to predict burnout and JS scores when used in combination. RESULTS: There were no significant differences between respondents and sampled nonrespondents in burnout scores (p = 0.56) or JS (p = 0.24). Prediction of burnout: The coefficient of multiple correlation, R2, indicated that in combination the independent variables accounted for 61% of the variance in burnout scores. The strongest predictor of burnout was job stress. Other job-related predictors of burnout were size of department, satisfaction with work, satisfaction with co-workers and co-worker support, job independence and job control, recognition by nursing, and role clarity. Personal-variable predictors were age, number of previous jobs held, social support, and intent to leave the field of respiratory care. Prediction of job satisfaction: R2 indicated that, in combination, the independent variables accounted for 63% of the variance observed in satisfaction with work, 36% of the variance observed in satisfaction with pay, 36% of the variance in satisfaction with promotions, 62% of the variance in satisfaction with supervision, and 48% of the variance in satisfaction with co-workers. Predictors of work-satisfaction level were recognition by physicians and nursing, age, burn-out level, absenteeism, and intent to leave the field. Predictors of level of satisfaction with pay were actual salary, job independence, organizational climate, ease of obtaining time off, job stress, absenteeism, intent to leave the field, and number of dependent children. Predictors of level of satisfaction with promotions were recognition by nursing, participation in decision making, job stress, intent to leave the field, past turnover rates, and absenteeism. Predictors of level of satisfaction with supervision included supervisor support, role clarity, independence, and ease of obtaining time off. The strongest predictor of level of satisfaction with co-workers was co-worker support. As overall level of JS increased, level of burnout decreased significantly (r = -0.59, p less than 0.001). As burnout level increased, increases occurred in absenteeism (r = 0.22, p less than 0.001), intent to leave the job (r = 0.48, p less than 0.001), and intent to leave the field (r = 0.51, p less than 0.001). CONCLUSIONS: Reduced job stress, increased job independence and job control, improved role clarity, and higher levels of JS were all associated with lower levels of burnout. Managerial attention to these factors may improve patient care and reduce absenteeism and turnover among RCPs.

Staff burnout among respiratory care personnel.

Comparison of burnout levels of respiratory care personnel and various job-related and demographic variables is revealing. Relationships are found that can help the respiratory care manager address the problem of burnout.