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Purpose Mechanical ventilation with ultra-low tidal volume (VT) during ARDS may reduce alveolar strain, driving pressure and hence ventilator-induced lung injury, with the main drawback of worsening respiratory acidosis. We hypothesized that VT could be reduced down to 4 ml/kg, with clinically significant decrease in driving pressure, without the need for extracorporeal CO.sub.2 removal, while maintaining pH > 7.20. Methods We conducted a non-experimental before-and-after multicenter study on 35 ARDS patients with PaO.sub.2/FiO.sub.2 [less than or equal to] 150 mmHg, within 24 h of ARDS diagnosis. After inclusion, VT was reduced to 4 ml/kg and further adjusted to maintain pH [greater than or equal to] 7.20, respiratory rate was increased up to 40 min.sup.-1 and PEEP was set using a PEEP-FiO.sub.2 table. The primary judgment criterion was driving pressure on day 2 of the study, as compared to inclusion. Results From inclusion to day 2, driving pressure decreased significantly from 12 [9-15] to 8 [6-11] cmH.sub.2O, while VT decreased from 6.0 [5.9-6.1] to 4.1 [4.0-4.7] ml/kg. On day 2, VT was below 4.2 ml/kg in 65% [CI.sub.95% 48%-79%], and below 5.25 ml/kg in 88% [CI.sub.95% 74%-95%] of the patients. 2 patients (6%) developed acute cor pulmonale after inclusion. Eleven patients (32%) developed transient severe acidosis with pH < 7.15. Fourteen patients (41%) died before day 90. Conclusion Ultra-low tidal volume ventilation may be applied in approximately 2/3 of moderately severe-to-severe ARDS patients, with a 4 cmH.sub.2O median reduction in driving pressure, at the price of transient episodes of severe acidosis in approximately 1/3 of the patients., Author(s): J. C. Richard [sup.1] [sup.2] [sup.3], S. Marque [sup.4], A. Gros [sup.5], M. Muller [sup.6], G. Prat [sup.7], G. Beduneau [sup.8] [sup.9], J. P. Quenot [sup.10], J. Dellamonica [sup.11], [...]

Purpose: Optimal fluid management in patients with acute respiratory distress syndrome (ARDS) is challenging due to risks associated with both circulatory failure and fluid overload. The performance of dynamic indices to predict fluid responsiveness (FR) in ARDS patients is uncertain., Methods: This post hoc analysis of the HEMOPRED study compared the performance of dynamic indices in mechanically ventilated patients with shock, with and without ARDS, to predict FR, defined as an increase in aortic velocity time integral (VTI)  > 10% after passive leg raising (PLR)., Results: Among 540 patients, 117 (22%) had ARDS and were ventilated with a median tidal volume of 7.6 mL/kg [6.9-8.4] and a median positive end-expiratory pressure of 7 cmH 2 O [5-9]. FR was observed in 45 ARDS patients (39% vs 44% in non-ARDS patients, p = 0.384). Reliability of dynamic indices to predict FR remained consistent in ARDS patients, though with different thresholds. Collapsibility index of the superior vena cava (ΔSVC) showed the best predictive performance in both ARDS (area under the curve [AUC] = 0.763 [0.659-0.868]) and non-ARDS (AUC = 0.750 [0.698-0.802]) patients. A right to left ventricle end-diastolic area ratio  > 0.8 or paradoxical septal motion were strongly linked to the absence of FR (> 80% specificity). FR was not associated with intensive care unit (ICU) mortality (47% vs. 46%, p = 1). However, hypovolemia, defined as an aortic VTI increase  > 32% during PLR (median increase in patients with a partial SVC collapse) was independently associated with ICU mortality (odds ratio [OR] = 1.355 [1.077-1.705], p = 0.011), as well as pulse pressure variation (OR = 1.014 [1.001-1.026], p = 0.034)., Conclusion: Performance of dynamic indices to predict FR appears preserved in ARDS patients, albeit with distinct thresholds. Hypovolemia, indicated by a  > 32% increase in aortic VTI during PLR, rather than FR, was associated with ICU mortality in this population., (© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Exploratory study to evaluate the association of different phenotypes of right ventricular (RV) involvement and mortality in the intensive care unit (ICU) in patients with acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19)., Methods: Post-hoc analysis of longitudinal data from the multicenter ECHO-COVID observational study in ICU patients who underwent at least two echocardiography examinations. Echocardiography phenotypes were acute cor pulmonale (ACP, RV cavity dilatation with paradoxical septal motion), RV failure (RVF, RV cavity dilatation and systemic venous congestion), and RV dysfunction (tricuspid annular plane systolic excursion ≤ 16 mm). Accelerated failure time model and multistate model were used for analysis., Results: Of 281 patients who underwent 948 echocardiography studies during ICU stay, 189 (67%) were found to have at least 1 type of RV involvements during one or several examinations: ACP (105/281, 37.4%), RVF (140/256, 54.7%) and/or RV dysfunction (74/255, 29%). Patients with all examinations displaying ACP had survival time shortened by 0.479 [0.284-0.803] times when compared to patients with all examinations depicting no ACP (P = 0.005). RVF showed a trend towards shortened survival time by a factor of 0.642 [0.405-1.018] (P = 0.059), whereas the impact of RV dysfunction on survival time was inconclusive (P = 0.451). Multistate analysis showed that patients might transit in and out of RV involvement, and those who exhibited ACP in their last critical care echocardiography (CCE) examination had the highest risk of mortality (hazard ratio (HR) 3.25 [2.38-4.45], P < 0.001)., Conclusion: RV involvement is prevalent in patients ventilated for COVID-19 ARDS. Different phenotypes of RV involvement might lead to different ICU mortality, with ACP having the worst outcome., (© 2023. Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To assess the impact of computerized transthoracic echocardiography (TTE) simulation on the learning curve to achieve competency in basic critical care echocardiography (CCE)., Methods: In this prospective bicenter study, noncardiologist residents novice in ultrasound followed either a previously validated training program with adjunctive computerized simulation on a mannequin (two 3 h-sessions; Vimedix simulator, CAE Healthcare) (interventional group; n = 12) or solely the same training program (control group; n = 12). All trainees from the same institution were assigned to the same study group to avoid confusion bias. Each trainee was evaluated after 1 (M1), 3 (M3) and 6 (M6) months of training using our previously validated scoring system. Competency was defined by a score ≥ 90% of the maximal value., Results: The 24 trainees performed 965 TTE in patients with cardiopulmonary compromise during their 6-month rotation. Skills assessments relied on 156 TTE performed in 106 patients (mean age 53 ± 14 years; mean Simplified Acute Physiologic Score 2: 55 ± 19; 79% ventilated). When compared to the control group, trainees of the interventional group obtained a significantly higher mean skills assessment score at M1 (41.5 ± 4.9 vs. 32.3 ± 3.7: P = 0.0004) and M3 (45.8 ± 2.8 vs. 42.3 ± 3.7: P = 0.0223), but not at M6 (49.7 ± 1.2 vs. 50.0 ± 2.7: P = 0.6410), due to higher practical and technical skills scores. Trainees of the control group required significantly more supervised TTE to obtain competency than their counterparts (36 ± 7 vs. 30 ± 9: p = 0.0145)., Conclusions: Adjunctive computerized simulation accelerates the learning curve of basic CCE in improving practical and technical skills and reduces the number of TTE examinations required to reach competency.

Purpose: We sought to determine the diagnostic ability of the end-expiratory inferior vena cava diameter (IVC EE ) to predict fluid responsiveness (FR) and the potential confounding effect of intra-abdominal pressure (IAP)., Methods: In this multicenter study, 540 consecutive ventilated patients with shock of various origins underwent an echocardiographic assessment by experts. The IVC EE , velocity time integral (VTI) of the left ventricular outflow tract (LVOT) and intra-abdominal pressure (IAP) were measured. Passive leg raising (PLR) was then systematically used to perform a reversible central blood volume expansion. FR was defined by an increase in LVOT VTI ≥ 10% after 1 min of PLR., Results: Since IVC EE was not obtained in 117 patients (22%), 423 were studied (septic shock: 56%), 129 of them (30%) having elevated IAP (≥ 12 mmHg) and 172 of them (41%) exhibiting FR. IVC EE  ≤ 13 mm predicted FR with a specificity of at least 80% in 62 patients (15%), while IVC EE  ≥ 25 mm predicted the absence of FR with a specificity of at least 80% in 61 patients (14%). In the remaining 300 patients (71%), the intermediate value of IVC EE did not allow predicting FR. An adjusted relationship between IVC EE and FR was observed while this relationship was less pronounced in patients with IAP ≥ 12 mmHg., Conclusions: Measurement of IVC EE in ventilated patients is moderately feasible and poorly predicts FR, with IAP acting as a confounding factor. IVC EE might add some value to guide fluid therapy but should not be used alone for fluid prediction purposes.

Purpose: Intubation of hypoxemic patients is associated with life-threatening adverse events. High-flow therapy by nasal cannula (HFNC) for preoxygenation before intubation has never been assessed by randomized study. Our objective was to evaluate the efficiency of HFNC for preoxygenation, compared to high fraction-inspired oxygen facial mask (HFFM)., Methods: Multicenter, randomized, open-labelled, controlled PREOXYFLOW trial (NCT 01747109) in six French intensive care units. Acute hypoxemic adults requiring intubation were randomly allocated to HFNC or HFFM. Patients were eligible if PaO2/FiO2 ratio was below 300 mmHg, respiratory rate at least 30/min and if they required FiO2 50% or more to obtain at least 90% oxygen saturation. HFNC was maintained throughout the procedure, whereas HFFM was removed at the end of general anaesthesia induction. Primary outcome was the lowest saturation throughout intubation procedure. Secondary outcomes included adverse events related to intubation, duration of mechanical ventilation and death., Results: A total of 124 patients were randomized. In the intent-to-treat analysis, including 119 patients (HFNC n = 62; HFFM n = 57), the median (interquartile range) lowest saturation was 91.5% (80-96) for HFNC and 89.5% (81-95) for the HFFM group (p = 0.44). There was no difference for difficult intubation (p = 0.18), intubation difficulty scale, ventilation-free days (p = 0.09), intubation-related adverse events including desaturation <80% or mortality (p = 0.46)., Conclusions: Compared to HFFM, HFNC as a preoxygenation device did not reduce the lowest level of desaturation.

Purpose: Use of ultrasound (US) when introducing central venous catheters (CVC) may improve success rates, reduce the number of needle punctures, and decrease complication rates, but has been hampered by supposed difficulty in learning how to perform the technique. This study describes the learning curve for US-guided jugular CVC placement after a training program., Methods: After an initial slide presentation and a video, intensivists who had not previously used US for CVC placement were evaluated qualitatively for US set up (score S1) and technical skills (score S2). Quantitative measures included durations of different components of the procedure (T1, time from entry of the US into the patient's room to sterile dressing of the intensivist; T2, time needed for sterile drapes, venous line preparation, and sterile sheath placement; T3, time from skin puncture to venous flashback; T4, time from guide insertion to dressing; T(tot), total duration of the procedure); number of skin punctures; and a difficulty score allocated by the intensivist., Results: We performed 150 evaluations of 30 intensivists: 50% had no prior experience of CVC placement and 50% no prior US experience. Maximal S1 and S2 scores were obtained with the fourth and eighth placement procedures, respectively. T1 and T2 did not change with ongoing training (5 and 8 min, respectively), but T3 and T4 decreased, from 5 min (first procedure) to less than 1 min (seventh procedure), and from 10 min (first procedure) to 7 min (sixth procedure), respectively. T(tot) decreased from 34 to 21 min at the eighth procedure. The number of skin punctures and the difficulty score decreased rapidly with the number of evaluations., Conclusions: Our study demonstrates that skills in US-guided CVC placement can easily be acquired with training.

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.

Purpose: Venous thromboembolism (VTE) is a frequent and serious problem in intensive care units (ICU). Anticoagulant treatments have demonstrated their efficacy in preventing VTE. However, when the bleeding risk is high, they are contraindicated, and mechanical devices are recommended. To date, mechanical prophylaxis has not been rigorously evaluated in any trials in ICU patients., Methods: In this multicenter, open-label, randomized trial with blinded evaluation of endpoints, we randomly assigned 407 patients with a high risk of bleeding to receive intermittent pneumatic compression (IPC) associated with graduated compression stockings (GCS) or GCS alone for 6 days during their ICU stay. The primary endpoint was the occurrence of a VTE between days 1 and 6, including nonfatal symptomatic documented VTE, or death due to a pulmonary embolism, or asymptomatic deep vein thrombosis detected by ultrasonography systematically performed on day 6., Results: The primary outcome was assessed in 363 patients (89.2%). By day 6, the incidence of the primary outcome was 5.6% (10 of 179 patients) in the IPC + GCS group and 9.2% (17 of 184 patients) in the GCS group (relative risk 0.60; 95% confidence interval 0.28-1.28; p = 0.19). Tolerance of IPC was poor in only 12 patients (6.0%). No intergroup difference in mortality rate was observed., Conclusions: With the limitation of a low statistical power, our results do not support the superiority of the combination of IPC + GCS compared to GCS alone to prevent VTE in ICU patients at high risk of bleeding.

Objective: To assess the impact of clinical guidelines to improve appropriate use of routine laboratory tests and bedside chest radiographs in a medical intensive care., Design: A two-year (Period-1: 2005, Period-2: 2006), retrospective, comparative study, before and after policy implementation., Patients: All consecutive patients admitted during the study periods., Setting: A university hospital 15-bed medical ICU., Intervention: Multifaceted intervention combining a daily routine prescription help-guide developed by a multidisciplinary group and displayed at patient's bedside, educational sessions and feedbacks by information on volumes of prescription. Individual adaptation to patient's clinical status was allowed by protocol., Assessment: The overall number and cost of laboratory tests and chest radiographs during Period-2 (with the help guide; from 01 to 12-2006) were compared to Period-1 (from 01 to 12-2005)., Results: Patients' general characteristics were similar during the two periods. A relative reduction of routine laboratory tests performance was observed per patient-ICU-day, ranging from 38 to 71.5% depending on the type of tests (P < 0.001 in all cases). For chest radiographs, a 41% relative reduction was observed between the two periods (P < 0.001). Daily ICU laboratory tests and chest radiographs cost per patient decreased from 114 to 56 euros. An overall 300,000 euros ICU cost reduction was directly related to the protocol implementation., Conclusion: The implementation of a laboratory tests and chest radiographs prescription protocol within our ICU induced an important cost saving.

Objective: Transesophageal echocardiography (TEE) is increasingly used in hemodynamic monitoring in the intensive care unit. This paper describes and validates a scoring system for assessing competence in TEE performed by intensivists for this indication., Design: Prospective study over an 18-month period., Settings: Two medical intensive care units., Methods: The scoring system is used to assess four aspects of TEE: quality of the views (score out of 14); semiquantitative evaluation of respiratory variations in the superior vena cava, valve regurgitation, size of the right ventricle (score out of 10); accuracy of measurement of velocity-time integrals for pulmonary and aortic flow, peak velocity of the E and A waves of mitral flow, left ventricular fractional area change (score out of 8); summary and proposed treatment (score out of 8). The scoring system was validated by using it to assess intensivists after 1 month (M1), 3 months (M3) and 6 months (M6) of training. TEE was done on a mechanically ventilated, hypotensive patient and scored by comparing the intensivist's examination with that of the expert examiner. The intensivists were divided into two groups of theoretical expertise at the start of training., Results: Nineteen intensivists were evaluated. The scores at M1 for level 0 (no experience in echocardiography) and level 1 (previous experience) were, respectively, 18.5 +/- 4 and 24.7 +/- 5. The scores at M1, M3, and M6 were, respectively, 20.4 +/- 5, 30.4 +/- 5 and 35.7 +/- 3. At M6, the intensivists had performed TEE 29 +/- 10 times., Conclusion: The scoring system was discriminatory and sensitive to change, and could be used as a tool to assess an intensivist's mastery of TEE.

Objective: To evaluate the effects of the humidification device on respiratory, hemodynamic and gas exchange parameters in acute respiratory distress syndrome (ARDS) patients., Design: A prospective open study., Setting: A medical intensive care unit of a university hospital., Patients: Acute respiratory distress syndrome patients, with hypercapnia (PaCO(2)>60 mmHg)., Intervention: A progressive reduction of the humidification system dead space (DSh). The following five conditions were tested sequentially: (1). heat and moisture exchanger (internal volume=95 ml) with a tracheal closed-suction system (internal volume=25 ml; total DSh=120 ml), (2). heat and moisture exchanger (internal volume=45 ml) with the closed-suction system (DSh=70 ml), (3). heat and moisture exchanger (internal volume=25 ml) with the closed-suction system (DSh=50 ml), (4). heated humidifier with the closed-suction system (DSh=25 ml) and (5). heated humidifier alone (DSh=0 ml). Recordings were performed at baseline and every 30 min after each artificial dead-space reduction. All ventilatory settings remained constant during the measurement periods., Results: Ten ARDS patients were included. A significant PaCO(2) decrease was observed at each humidification system dead-space reduction, compared to baseline: PaCO(2 )=80.3+/-20 mmHg at DSh(120) compared to PaCO(2 )=63.6+/-13 mmHg at DSh(0) ( p<0.05). No changes were observed for hemodynamic and ventilatory parameters between the different humidification devices., Conclusion: Artificial airway dead-space reduction allows a significant PaCO(2) reduction. Independently of any respiratory mechanical changes, this very simple maneuver may be of importance when low tidal volume ventilation is used in ARDS patients, and when PaCO(2) lowering is warranted.

Objective: To evaluate the clinical efficacy of noninvasive continuous positive airway pressure ventilation (CPAP) using a new interface, constituted by a cephalic plastic helmet, in comparison with a standard facial mask., Design and Setting: A prospective pilot study with matched-control group, in the emergency department of a teaching hospital., Patients and Methods: Eleven consecutive adult patients with acute hypoxemic respiratory failure related to cardiogenic pulmonary edema (whether hypercapnic or not) were enrolled in the study, after failure of the initial medical treatment. Each patient treated with CPAP, using the helmet in addition to a standardized medical treatment, was matched with historical control-patient treated with CPAP using a standard facial mask, and selected by gender, age, and PaCO2 levels on admission. Primary end points were improvements of gas exchanges and clinical parameters of respiratory distress. tolerance was evaluated after each CPAP trial., Results: The 22 patients and controls had similar characteristics at baseline. PaCO2 levels, and clinical parameters improved similarly in both groups. No interface intolerance was reported whether using standard facial mask or the helmet. No complications were observed in either group. The helmet allowed CPAP administration for a longer period of time (p=0.045). In-hospital mortality was not different between the two groups., Conclusion: Despite a high dead-space volume (9-15 l), this new helmet interface is an efficient alternative to standard face mask during CPAP, even in cases of severe respiratory acidosis and hypercapnia. It allowed to provide long-duration CPAP, without any adverse events or clinical intolerance.