Number of supervised studies required to reach competence in advanced critical care transesophageal echocardiography.

PURPOSE: To determine the minimum number of supervised transesophageal echocardiography (TEE) that intensivists should perform to reach competence in performing and interpreting a comprehensive hemodynamic assessment in ventilated intensive care unit patients. METHODS: Prospective and multicentric study. Skills of 41 intensivists (trainees) with no (level 0) or little (level 1) experience in echocardiography was evaluated over a 6-month period, using a previously validated skills assessment score (/40 points). Trainees were evaluated at 1 (M1), 3 (M3) and 6 months (M6) by their tutor while performing 2 TEE examinations in ventilated patients. Competence was a priori defined by a skills assessment score >35/40 points. RESULTS: No difference in the score was observed between level 0 and level 1, except at M1 (22.2 ± 6.2 vs. 25.9 ± 4.4 points, p = 0.03). After 6 months, trainees performed a mean of 31 ± 9 supervised TEE. The score gradually increased from M1 to M6 (24 ± 6, 32 ± 3, and 35 ± 3 points, p < 0.001), regardless of trainees' initial level. A correlation was found between the number of supervised TEE and the skills assessment score (r (2) = 0.60; p < 0.001). The number of supervised TEE examinations which best predicted a score >35/40 points was 25, with a sensitivity of 81 % and a specificity of 93 % (area under the ROC curve: 0.91 ± 0.04). A number of 31 supervised TEE examinations predicted a score >35/40 points with a specificity close to 100 %. CONCLUSION: The performance of at least 31 supervised examinations over 6 months is required to reach competence in TEE driven hemodynamic evaluation of ventilated patient.

Impact of humidification and nebulization during expiratory limb protection: an experimental bench study.

BACKGROUND: Different filtering devices are used during mechanical ventilation to avoid dysfunction of flow and pressure transducers or for airborne microorganisms containment. Water condensates, resulting from the use of humidifiers, but also residual nebulization particles may have a major influence on expiratory limb resistance. OBJECTIVES: To evaluate the influence of nebulization and active humidification on the resistance of expiratory filters. METHODS: A respiratory system analog was constructed using a test lung, an ICU ventilator, heated humidifiers, and a piezoelectric nebulizer. Humidifiers were connected to different types of circuits (unheated, mono-heated, new-generation and old-generation bi-heated). Five filter types were evaluated: electrostatic, heat-and-moisture exchanger, standard, specific, and internal heated high-efficiency particulate air [HEPA] filter. Baseline characteristics were obtained from each dry filter. Differential pressure measurements were carried out after 24 hours of continuous in vitro use for each condition, and after 24 hours of use with an old-generation bi-heated circuit without nebulization. RESULTS: While using unheated circuits, measurements had to be interrupted before 24 hours for all the filtering devices except the internal heated HEPA filter. The heat-and-moisture exchangers occluded before 24 hours with the unheated and mono-heated circuits. The circuit type, nebulization practice, and duration of use did not influence the internal heated HEPA filter resistance. CONCLUSION: Expiratory limb filtration is likely to induce several major adverse events. Expiratory filter resistance increase is due mainly to the humidification circuit type, rather than to nebulization. If filtration is mandatory while using an unheated circuit, a dedicated filter should be used for ≤ 24 hours, or a heated HEPA for a longer duration.

Clinical relevance of classification according to weaning difficulty.

OBJECTIVE: To evaluate the clinical relevance of the weaning from mechanical ventilation classification system derived from the 2005 international consensus conference, in patients who receive mechanical ventilation for more than 48 hours, and evaluate its correlation with prognosis. METHODS: We conducted a retrospective cohort study in a 12-bed intensive care unit (ICU) in a teaching hospital. We included patients who required > 48 hours of mechanical ventilation and who passed a spontaneous breathing trial (SBT). Weaning and sedation were monitored according to standardized protocol-directed procedures. We collected data on physiological characteristics, mechanical ventilation duration, ICU and hospital stay, and mortality from the medical records database. We assessed one-year mortality with a prospective, standardized method. Multivariate logistic regression was performed to evaluate the association between weaning categories and outcome. RESULTS: We included 329 ventilation episodes, in which 115 patients passed at least one SBT. Thirty-four patients (30%) succeeded in their first SBT (simple weaning group), 47 patients (40%) succeeded in their 2nd or 3rd SBT or in less than 7 days of weaning (the difficult weaning group), and 34 patients (30%) required more than 3 SBTs or more than 7 days of weaning (the prolonged weaning group). There were significant differences in ICU and hospital mortality between the simple, difficult, and prolonged-weaning groups. Prolonged weaning was an independent risk factor for longer ICU stay (odds ratio 15.11, 95% CI 1.61-141.91, P = .01) and hospital mortality (odds ratio 3.66, 95% CI 0.99-13.51). However, the weaning process did not impact one-year mortality (odds ratio 2.61, 95% CI 0.82-8.35). CONCLUSIONS: The new weaning classification system is clinically relevant and correlates to ICU and hospital mortality, but not to one-year mortality.