Francesco Simeone

Comparison of 3 different methods used to measure the rapid shallow breathing index

PURPOSE Rapid shallow breathing index (RSBI) is conveniently measured through the ventilator. If continuous positive airway pressure (CPAP) is used, it may change the RSBI value. We measured the RSBI with a handheld spirometer and through the ventilator, with and without CPAP, to assess differences. MATERIALS AND METHODS Rapid shallow breathing index was measured in 3 ways: (1) CPAP 0 cm H(2)O and fraction of inspired oxygen (Fio(2)) 0.4, (2) CPAP 5 cm H(2)O and Fio(2) 0.4, and (3) ventilator disconnected and Fio(2) 0.21. Tidal volume and respiratory frequency were recorded from ventilator monitor values in methods 1 and 2, and from a handheld spirometer and observed respiratory frequency, in method 3. RESULTS A total of 170 measurements, each using all 3 methods, were obtained from 80 patients admitted to a medical intensive care unit. The mean RSBI values for methods 1, 2, and 3 were 98.1 ± 58.7, 87.6 ± 51.2, and 108.3 ± 65.3, respectively (P < .001). The RSBI decreased by 9.4% when using CPAP 0 cm H(2)O and by 19.1% when using CPAP 5 cm H(2)O. CONCLUSIONS The RSBI values measured through the ventilator with CPAP 5 cm H(2)O are much lower than the values measured with a handheld spirometer. Even the RSBI values measured with CPAP 0 cm H(2)O are significantly lower. This is attributable to the base flow delivered by some ventilators. The difference must be taken into account during weaning assessment.

A new endotracheal tube designed to enable a single operator to perform percutaneous dilatational tracheostomy while maintaining the airway, providing continuous bronchoscopic guidance, and minimizing procedural complications: demonstration of feasibility on a mannequin and a cadaver.

Background:We designed a double-lumen endotracheal tube (the EZ [Easy] Tracheostomy [EZT]) to enable a single operator to safely perform percutaneous dilatational tracheostomy (PDT) at the bedside while providing continuous bronchoscopic guidance. The EZT design also aims to ensure uninterrupted mechanical ventilation during most of the PDT procedure via a secure airway. It aims to significantly minimize hypoxia, hypoventilation, auto-positive end-expiratory pressure, airway loss, posterior wall laceration, and damage to the endoscope related to the current methodology. Method:We demonstrated the feasibility of our method on a mannequin model and a cadaver. Results:Single operators successfully performed the modified PDT on their first attempt with excellent visualization and no obvious complications. The potential for minimal interruption in ventilation, low risk of airway loss or malpositioning, and significant reduction in other PDT-related complications were clearly demonstrated. The procedure was found to be easier to perform when compared with conventional PDT. Conclusions:It is feasible for a single operator to perform PDT with continuous bronchoscopic guidance when using the EZT on cadaver and mannequin models. Clinical studies are warranted to evaluate this new tool.

The Effect of Flow Trigger on Rapid Shallow Breathing Index Measured Through the Ventilator

Background: The rapid shallow breathing index (RSBI) has the best predictive value to assess readiness for weaning from mechanical ventilation. At many institutions, this index is conveniently measured without disconnecting the patient from the ventilator, but this method may be inaccurate. Because modern ventilators have a base flow in the flow trigger mode that may provide a substantial help to the patient, we hypothesized that the RSBI is significantly decreased when measured through the ventilator with flow trigger even without continuous positive airway pressure (CPAP) and pressure support (PS). Methods: The RSBI was calculated using the values of minute ventilation and respiratory rate obtained either through the digital display of the ventilator or from a digital ventilometer. The RSBI was measured using 3 different methods: method 1, CPAP and PS both 0 cm H2O with flow trigger; method 2, CPAP and PS both 0 cm H2O without flow trigger; and method 3, using digital ventilometer. Results: A total of 165 measurements per method were obtained in 80 adult patients in the medical intensive care unit (MICU). The RSBI (breaths/min/L) values were 70.2 ± 26.5 with method 1, 85.4 ± 30.3 with method 2, and 80.1 ± 30.3 with method 3. The RSBI was significantly decreased using mechanical ventilation with flow trigger as compared with mechanical ventilation without flow trigger (P < .0001) or digital ventilometer (P < .0001). When method 1 was compared with methods 2 and 3, the RSBI decreased by 17% and 12%, respectively. Conclusions: The RSBI measurement is significantly decreased by the base flow delivered through modern ventilators in the flow trigger mode. If RSBI is measured through the ventilator in the flow trigger mode, the difference should be considered when using RSBI to assess readiness for weaning from mechanical ventilation.

A 24-Hour Postintensive Care Unit Transition-of-Care Model Shortens Hospital Stay:

Background: Patients discharged early from the medical intensive care unit (MICU) are at risk of deterioration, MICU readmission, and increased mortality. An earlier discharge to a medical ward is desirable to reduce costs but it may adversely affect outcomes. To address this problem, a new model for the MICU transition of care was implemented at our academic center: The MICU team continued to manage all patients transferred from the MICU to the medical ward for at least 24 hours. Methods: Data were collected for all MICU patients admitted 1 year before and 1 year after the intervention. Hospital length of stay (LOS) after transfer from the MICU, readmission rate, and mortality rate were compared before and after the intervention. A nonparsimonious propensity model based on 30 factors was used to identify matched preintervention and postintervention cohorts. Results: A total of 618 of the 848 patients admitted to the MICU were transferred to medical ward during the year prior to the implementation of the new model, and 600 of the 883 patients were transferred during the following year. Pre- and postintervention cohorts were well matched (n = 483 patients in each group). Poisson regression analysis showed a decrease in the hospital LOS after MICU transfer by 1.17 days (P < .001) without a significant change in adjusted mortality (lower by 1.9%, P = .181) and MICU readmission rates (lower by 2%, P = .264). Conclusion: A new model for the post-MICU transition of care, with the MICU team continuing to manage all patients transferred to the medical ward for at least 24 hours, significantly decreased duration of hospital stay after MICU transfer without affecting MICU readmission and mortality rate. The implementation of this model may lower medical costs and make transition of care safer without adverse outcomes.

Critical airway management: a suggested modification to the rigid fiber-optic stylet based on 301 novice intubations.

Background:Emergent airways in critically ill patients outside the operating room (critical airways) are often difficult airways frequently managed by intensivists. Current advanced airway management tools have not been adequately evaluated for critical airways and are not specifically designed for intensivists. The rigid fiber-optic stylet has the potential to fill this niche as it is an established difficult intubation technique very similar to bronchoscopy. The purpose of this study was to evaluate the rigid fiber-optic stylet and identify characteristics that would affect its use for critical airway management by intensivists. Methods:A retrospective, single-center, observational study was performed in the setting of a tertiary care university teaching hospital. A total of 301 consecutive elective surgery patients underwent endotracheal intubation attempted by a novice using a rigid fiber-optic stylet. Results:Novices could successfully intubate >95% patients using the rigid fiber-optic stylet. Most patients were intubated within 2 attempts (93%) in a median time of 73 seconds. In all the cases of intubation failure by novices, the staff anesthesiologist could successfully intubate the patient in his first attempt with an average time of 32 seconds. By studying unsuccessful attempts, we identified an important barrier to the adaptation of this tool for critical airway management—the absence of working channels, which does not allow suctioning, oxygenation, or instillation of lidocaine. Conclusions:A multilumen sheath designed with 2 working channels has the potential to overcome all identified barriers to the use of rigid fiber-optic stylet as a critical airway management device by intensivists. This modification should be evaluated in a clinical study.

Low-Dose Tissue Plasminogen Activator in Pulmonary Embolism: Benefit Remains Unclear

Age, y 58.0 6 17.6 46.5 6 23.0 52.4 6 21.0 Length of stay, d 19 6 43 23 6 11 20.9 6 31 Admission unit Trauma 17 (34) 22 (44) 39 (39) General Surgery 14 (30) 10 (20) 24 (24) Medical 9 (18) 10 (20) 19 (19) Cardiovascular Surgery 9 (18) 8 (16) 17 (17) APACHE II score 18 6 9 20 6 6 19 6 8 Corticosteroids 15 (30) 18 (36) 33 (33) Antibiotic 45 (90) 47 (94) 92 (92) Duration, d 11.3 6 8.2 18.0 6 12.7 14.8 6 11.0 Mechanical ventilation 44 (88) 48 (96) 92 (92) Duration, d 10.4 6 8.8 19.2 6 12.3 15.1 6 12.0 Mortality 7 (14) 7 (14) 14 (14)