A GAVeCeLT consensus on the indication, insertion, and management of central venous access devices in the critically ill.

Central venous access devices are essential for the management of critically ill patients, but they are potentially associated with many complications, which may occur during or after insertion. Many evidence-based documents-consensus and guidelines-suggest practical recommendations for reducing catheter-related complications, but they have some limitations. Some documents are not focused on critically ill patients; other documents address only some special strategies, such as the use of ultrasound; other documents are biased by obsolete concepts, inappropriate terminology, and lack of considerations for new technologies and new methods. Thus, the Italian Group of Venous Access Devices (GAVeCeLT) has decided to offer an updated compendium of the main strategies-old and new-that should be adopted for minimizing catheter-related complications in the adult critically ill patient. The project has been planned as a consensus, rather than a guideline, since many issues in this field are relatively recent, and few high-quality randomized clinical studies are currently available, particularly in the area of indications and choice of the device. Panelists were chosen between the Italian vascular access experts who had published papers on peer-reviewed journals about this topic in the last few years. The consensus process was carried out according to the RAND/University of California at Los Angeles (UCLA) Appropriateness Methodology, a modification of the Delphi method, that is, a structured process for collecting knowledge from groups of experts through a series of questionnaires. The final document has been structured as statements which answer to four major sets of questions regarding central venous access in the critically ill: (1) before insertion (seven questions), (2) during insertion (eight questions), (3) after insertion (three questions), and (4) at removal (three questions).

ESICM guidelines on acute respiratory distress syndrome: definition, phenotyping and respiratory support strategies.

The aim of these guidelines is to update the 2017 clinical practice guideline (CPG) of the European Society of Intensive Care Medicine (ESICM). The scope of this CPG is limited to adult patients and to non-pharmacological respiratory support strategies across different aspects of acute respiratory distress syndrome (ARDS), including ARDS due to coronavirus disease 2019 (COVID-19). These guidelines were formulated by an international panel of clinical experts, one methodologist and patients' representatives on behalf of the ESICM. The review was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. We followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of evidence and grade recommendations and the quality of reporting of each study based on the EQUATOR (Enhancing the QUAlity and Transparency Of health Research) network guidelines. The CPG addressed 21 questions and formulates 21 recommendations on the following domains: (1) definition; (2) phenotyping, and respiratory support strategies including (3) high-flow nasal cannula oxygen (HFNO); (4) non-invasive ventilation (NIV); (5) tidal volume setting; (6) positive end-expiratory pressure (PEEP) and recruitment maneuvers (RM); (7) prone positioning; (8) neuromuscular blockade, and (9) extracorporeal life support (ECLS). In addition, the CPG includes expert opinion on clinical practice and identifies the areas of future research.

Can carotid artery Doppler variations induced by the end-expiratory occlusion maneuver predict fluid responsiveness in septic shock patients?

BACKGROUND: An increase in cardiac index (CI) during an end-expiratory occlusion test (EEOt) predicts fluid responsiveness in ventilated patients. However, if CI monitoring is unavailable or the echocardiographic window is difficult, using the carotid Doppler (CD) could be a feasible alternative to track CI changes. This study investigates whether changes in CD peak velocity (CDPV) and corrected flow time (cFT) during an EEOt were correlated with CI changes and if CDPV and cFT changes predicted fluid responsiveness in patients with septic shock. METHODS: Prospective, single-center study in adults with hemodynamic instability. The CDPV and cFT on carotid artery Doppler and hemodynamic variables from the pulse contour analysis EV1000™ were recorded at baseline, during a 20-s EEOt, and after fluid challenge (500 mL). We defined responders as those who increased CI ≥ 15% after a fluid challenge. RESULTS: We performed 44 measurements in 18 mechanically ventilated patients with septic shock and without arrhythmias. The fluid responsiveness rate was 43.2%. The changes in CDPV were significantly correlated with changes in CI during EEOt (r = 0.51 [0.26-0.71]). A significant, albeit lower correlation, was found for cFT (r = 0.35 [0.1-0.58]). An increase in CI ≥ 5.35% during EEOt predicted fluid responsiveness with 78.9% sensitivity and 91.7% specificity, with an area under the ROC curve (AUROC) of 0.85. An increase in CDPV ≥ 10.5% during an EEOt predicted fluid responsiveness with 96.2% specificity and 53.0% sensitivity with an AUROC of 0.74. Sixty-one percent of CDPV measurements (from - 13.5 to 9.5 cm/s) fell within the gray zone. The cFT changes during EEOt did not accurately predict fluid responsiveness. CONCLUSIONS: In septic shock patients without arrhythmias, an increase in CDPV greater than 10.5% during a 20-s EEOt predicted fluid responsiveness with > 95% specificity. Carotid Doppler combined with EEOt may help optimize preload when invasive hemodynamic monitoring is unavailable. However, the 61% gray zone is a major limitation (retrospectively registered on Clinicaltrials.gov NCT04470856 on July 14, 2020).

Midline catheters for extracorporeal photopheresis in hematological patients.

INTRODUCTION: Peripheral venous access for extracorporeal photopheresis (ECP) may be difficult in graft versus host disease (GVHD) patients, because of previous intravenous therapies and multiple peripheral cannulations; in this population of patients, ultrasound guided midline catheters may be an alternative option to central venous access. METHODS: In this single-center, prospective preliminary study, we enrolled all consecutive patients with a diagnosis of GVHD and candidate to ECP, over a period of 10 months. We used inserted power injectable, non-valved, polyurethane, 20-25 cm single lumen midline catheters (MC). RESULTS: Sixty-nine ECP procedures were carried out in six patients, using single-lumen MCs for outflow (5Fr in 74% and 4Fr in 26% of cases). For inflow, we used 5Fr or 4Fr MCs, or central venous access devices previously placed for other clinical reasons. There were no catheter-related complications during the entire period of ECP treatment. Mean outflow was significantly higher for 5Fr than for 4Fr MCs (35.8 ± 7.3 vs 29.2 ± 7.8 ml/min; p = 0.0008) and the procedure time was significantly shorter (92.9 ± 9.2 vs 108 ± 13.2 min; p < 0.0001). CONCLUSION: In GVHD patients, ECP can be performed efficiently and safely using single lumen polyurethane power injectable MCs. The best results are obtained with 5Fr rather than with 4Fr catheters. This strategy of venous access should be implemented in DIVA patients requiring ECP treatments, and probably also in other types of apheresis.

Ultrasound-guided access to the axillary vein for implantation of cardiac implantable electronic devices: A systematic review and meta-analysis.

The aims of our systematic review were to quantify the expected rate of procedural success, early and late complications during CIED implantation using US-guided puncture of the axillary vein and to perform a meta-analysis of those studies that compared the US technique (intervention) versus conventional techniques (control) in terms of complication rates. MEDLINE, ISI Web of Science, and EMBASE were searched for eligible studies. Pooled Odds Ratio (OR) and Pooled Mean Difference (PMD) for each predictor were calculated. The quality of evidence (QOE) was evaluated according to the GRADE guidelines. Thirteen studies were included a total of 2073 patients. The overall success of US-guided venipuncture for CIED implantation was 96.8%. As regards early complications, pneumothorax occurred in 0.19%, arterial puncture in 0.63%, and severe hematoma/bleeding requiring intervention in 1.1%. No cases of hemothorax, brachial plexus, or phrenic nerve injury were reported. As regards late complications, the incidence of pocket infection, venous thromboembolism, and leads dislodgement was respectively 0.4%, 0.8%, and 1.2%. In the meta-analysis (five studies), the intervention group (US-guided venipuncture) had a trend versus a lower likelihood of having a pneumothorax (0.19% vs 0.75%, p = 0.21), pocket hematoma (0.8% vs 1.7%, p = 0.32), infection (0.28% vs 1.05%, p = 0.29) than the control group, but this did not reach statistical significance. The overall QOE was low or very low. In conclusions we found that the US-guided axillary venipuncture for CIEDs implantation was associated with a low incidence of early and late complications and a steep learning curve.

Secondary malposition of a PICC-port due to heavy physical exercise: A case report.

Physical exercise is often encouraged in cancer patients, mainly for the purpose of rehabilitation and for its psychological benefit. Some authors also suggest that exercise-specially in patient with peripherally inserted central venous access devices-may contribute to reduce the risk of catheter-related thrombosis. Still, the impact of physical exercise on the risk of device-related complications is not yet defined.We report a case of secondary migration of the tip of an arm port, caused by high-intensity exercise in a woman undergoing chemotherapy because of ovarian cancer. Tip migration was suspected because of malfunction (persistent withdrawal occlusion) and diagnosis established after ultrasound examination and chest x-ray.Even if exercise may yield benefit in the cancer patient on chemotherapy, the risk of mechanical complication of the venous access device-such as tip migration-should be considered in the case of high-intensity exercise.

An ultrasound-based technique in the management of totally implantable venous access devices with persistent withdrawal occlusion.

Persistent withdrawal occlusion is a specific catheter malfunction characterized by inability to withdraw blood through the device while infusion is maintained. The main causes are fibroblastic sleeve and tip malposition (associated or not to venous thrombosis around the tip). All current guidelines recommend infusing vesicant/antiblastic drugs through a central venous port only after assessment of blood return. In PWO, blood return is impossible. We have recently started to assess the intravascular position of the tip and the delivery of the infusion in the proximity of the cavo-atrial junction utilizing transthoracic/subxiphoid ultrasound with the 'bubble test'. We found that this is an easy, real-time, accurate and safe method for verifying the possibility of using a port for chemotherapy even in the absence of blood return, as it occurs with persistent withdrawal occlusion.

Incidence, characteristics, and outcome of out-of-hospital cardiac arrest in Italy: A systematic review and meta-analysis.

Introduction: Data on out-of-hospital cardiac arrest (OHCA) is limited in Italy, and there has never been a comprehensive systematic appraisal of the available evidence. Therefore, this review aims to explore the incidence, characteristics, and outcome of OHCA in Italy. Methods: We systematically searched PubMed, Embase, Google Scholar, ResearchGate, and conference proceedings up to September 23, 2022. Studies investigating OHCA in Italy and reporting at least one outcome related to cardiac arrest were considered eligible. The primary outcome was survival at the longest follow-up available. Risk of bias was assessed using the Joanna Briggs Institute critical appraisal tool. A random-effects model proportion meta-analysis was performed to calculate the pooled outcomes with 95% confidence interval (CI). Results: We included 42 studies (43,042 patients) from 13 of the 20 Italian regions published between 1995 and 2022. Only five studies were deemed to be at low risk of bias. The overall average incidences of OHCA attended by emergency medical services and with resuscitation attempted were 86 (range: 10-190) and 55 (range: 6-108) per 100,000 populations per year, respectively. Survival at the longest follow-up available was 9.0% (95% CI, 6.7-12%; 30 studies and 15,195 patients) in the overall population, 25% (95% CI, 21-30%; 16 studies and 2,863 patients) among patients with shockable rhythms, 28% (95% CI, 20-37%; 8 studies and 1,292 patients) among the Utstein comparator group. Favourable neurological outcome was 5.0% (95% CI, 3.6-6.6%; 16 studies and 9,675 patients). Return of spontaneous circulation was achieved in 19% (95% CI, 16-23%; 40 studies and 30,875 patients) of cases. Bystanders initiated cardiopulmonary resuscitation in 26% (95% CI, 21-32%; 33 studies and 23,491 patients) of cases but only in 3.2% (95% CI, 1.9-4.9%; 9 studies and 8,508 patients) with an automated external defibrillator. The mean response time was 10.2 (95% CI, 8.9-11.4; 25 studies and 23,997 patients) minutes. Conclusions: Survival after OHCA in Italy occurred in one of every ten patients. Bystanders initiated cardiopulmonary resuscitation in only one-third of cases, rarely with a defibrillator. Different areas of the country collected data, but an essential part of the population was not included. There was high heterogeneity and large variation in outcomes results and reporting, limiting the confidence in the estimates of incidence and outcome. Creating and maintaining a nationwide registry is a priority.

A comparison between two radiological criteria for verifying tip location of central venous catheters.

INTRODUCTION: Current guidelines recommend intraprocedural methods-such as Intra-Cavitary ECG (IC-ECG) and echocardiography-for verifying the location of the tip of central venous catheters. Nonetheless, there are clinical conditions which may require to verify tip location by less accurate methods such as Chest X-Ray (CXR). We have compared the feasibility and accuracy of two radiological methods for tip location-the Sweet Spot Criterion (SSC) and the Carina Criterion (CC)-using IC-ECG as reference. METHODS: In this retrospective multicenter study, we reviewed the radiology databases of three hospitals, examining all CXRs performed on patients after insertion of Peripherally Inserted Central Catheters (PICCs), as long as the tip location had been successfully performed during the procedure by IC-ECG. Tip location was verified using SSC and CC, comparing the two methods in terms of feasibility and accuracy. RESULTS: We reviewed the CXR of 1116 PICCs successfully inserted by IC-ECG. CC was not feasible in 0.5% (impossible visualization of the carina) and difficult in 1.5%; in 97.7% of cases, the position of the tip was adequate (1-5 cm below the carina), in 0.6% too high (<1 cm), in 1.2% too low (6-9 cm). On the other hand, because of unclear visualization of radiological landmarks, SSC was not feasible in 0.9% and difficult in 10.5%; though, according to SSC the tip location was always acceptable (in 94.2% the tip was in the middle of the spot, in 2.5% close to the superior border, and in 2.3% close to the inferior border); no tip was visualized outside of the spot. CONCLUSION: CC and SSC were similar in terms of feasibility (99.5% vs 99.1%) and accuracy (98.1% vs 100%), though CC was subjectively perceived to be easier and more rapid to perform.

A new pressure-based device for tip navigation and tip location during central venous catheterization: A prospective clinical study on a cohort of 136 adult patients.

INTRODUCTION: According to current guidelines, tip location of peripherally inserted central catheters (PICCs) should be verified during insertion, preferably using non-invasive methods such as intracavitary ECG (IC-ECG) or echocardiography. An interesting new option is represented by a new pressure-based device, the CatFinder System (CFS), which might be theoretically useful also for tip navigation. METHODS: We planned a single-center, prospective, non-randomized trial on adult patients requiring PICC insertion, using simultaneously CFS and IC-ECG, with the purpose of verifying the applicability, feasibility, safety, and accuracy of CFS for intra-procedural tip location. Patients with known ECG abnormalities or cardiac diseases of any type were excluded. The ability of CFS to assess wrong directions of the catheter during insertion (tip navigation) was evaluated by comparison with ultrasound scan. RESULTS: Out of 136 enrolled adult patients, CFS was found to be applicable in 131 cases (five cases were excluded because of ECG abnormalities) and feasible in 111 cases (in 20 cases, tip location by CFS could not be carried out because of technical issues). There were no complications directly or indirectly related to the CFS maneuvers. Using IC-ECG as a comparison, 87 tips placed by CFS were within 2 cm from the target, 17 were >2 cm from target. In seven cases, CFS was able to detect a wrong direction (to the ipsilateral internal jugular vein), as confirmed by ultrasound. CONCLUSION: Applicability of CFS in patients with sinus rhythm was 96.3%, feasibility was 84.7%, and safety was 100%. If compared to IC-ECG, accuracy was 83.6% (accepting an error <2 cm) and 96.1% (for an error <3 cm). Unacceptable tip positions (>3 cm) were 3.8% (the tip was too high inside the SVC). This study confirms a possible future role of CFS for intra-procedural tip location and tip navigation, though its use cannot be currently recommended.

Prospective clinical study on the incidence of catheter-related complications in a neurological intensive care unit: 4 years of experience.

INTRODUCTION: Over the past decades, significant efforts have been made to reduce early and late catheter-related complications in critically ill patients, using approaches based on bundles of evidence-based interventions. METHODS: In this prospective clinical study, the authors evaluated the incidence of catheter-related complications in their neuro-intensive care unit during a 4-year period, adopting systematically the GAVeCeLT bundles for the insertion and management of all central venous access devices: centrally inserted central catheters (CICCs), peripherally inserted central catheters (PICCs) and femorally inserted central catheters (FICCs). All early/immediate and late complications were recorded. RESULTS: On 486 central lines (328 CICCs, 149 PICCs and 9 FICCs), the only clinically relevant early/immediate complication was primary tip malposition (1%). In regards late infective complications, the authors did not record any case of catheter-related bloodstream infection; though, they observed one case of central line associated blood stream infection (one CICC; 0.14/1000 catheter days), and 15 cases of catheter colonization (12 CICCs and 3 PICCs; 2.09 episodes/1000 catheter days). Late non-infective complications were few: 14 accidental dislodgments (2.9%), 18 irreversible lumen occlusions (3.7%), and no episodes of symptomatic catheter-related thrombosis or tip migration. CONCLUSION: The systematic adoption of the GAVeCeLT bundles for CVAD insertion and maintenance was associated with a minimization of catheter-related complications. The strict adherence to the recommendations included in these bundles was the major determinant for clinical success.

Machine learning model prediction of 6-month functional outcome in elderly patients with intracerebral hemorrhage.

Spontaneous intracerebral hemorrhage (ICH) has an increasing incidence and a worse outcome in elderly patients. The ability to predict the functional outcome in these patients can be helpful in supporting treatment decisions and establishing prognostic expectations. We evaluated the performance of a machine learning (ML) model to predict the 6-month functional status in elderly patients with ICH leveraging the predictive value of the clinical characteristics at hospital admission. Data were extracted by a retrospective multicentric database of patients ≥ 70 years of age consecutively admitted for the management of spontaneous ICH between January 1, 2014 and December 31, 2019. Relevant demographic, clinical, and radiological variables were selected by a feature selection algorithm (Boruta) and used to build a ML model. Outcome was determined according to the Glasgow Outcome Scale (GOS) at 6 months from ICH: dead (GOS 1), poor outcome (GOS 2-3: vegetative status/severe disability), and good outcome (GOS 4-5: moderate disability/good recovery). Ten features were selected by Boruta with the following relative importance order in the ML model: Glasgow Coma Scale, Charlson Comorbidity Index, ICH score, ICH volume, pupillary status, brainstem location, age, anticoagulant/antiplatelet agents, intraventricular hemorrhage, and cerebellar location. Random forest prediction model, evaluated on the hold-out test set, achieved an AUC of 0.96 (0.94-0.98), 0.89 (0.86-0.93), and 0.93 (0.90-0.95) for dead, poor, and good outcome classes, respectively, demonstrating high discriminative ability. A random forest classifier was successfully trained and internally validated to stratify elderly patients with spontaneous ICH into prognostic subclasses. The predictive value is enhanced by the ability of ML model to identify synergy among variables.

Risk of thrombophlebitis associated with continuous peripheral infusion of vancomycin: The effect of dilution.

INTRODUCTION: Although several guidelines recommend that prolonged administration of vancomycin should be preferably carried out by a central venous access, vancomycin is often given peripherally. Whether such risk may be affected by different modalities of administration in terms of dilution and time of infusion, it is a matter of controversy. METHODS: This single-center prospective study enrolled all consecutive patients requiring prolonged intravenous infusion of vancomycin (1 g/day) using long peripheral cannula "mini-midline." Patients were randomized in study group (4 mg/ml) and control group (20 mg/ml). All patients were systematically evaluated every 24 h by the Visual Exit-Site Score and a daily ultrasound scan of the veins of the arm. RESULTS: The daily ultrasound evaluation showed venous thrombosis at the distal tip of the cannula in all patients, in both groups. After this finding in the first 14 patients, the study was interrupted. All thromboses were completely asymptomatic and occurred in absence of any sign of catheter malfunction. The onset of thrombosis was significantly earlier in the control group (ranging from 24 to 48 h) than in the study group (ranging from 48 to 96 h), with an average of 30 ± 11 versus 68 ± 16 h (p < 0.001). CONCLUSION: Continuous intravenous infusion of vancomycin should be preferably delivered by a central venous access, as largely recommended by current guidelines, since peripheral infusion is inevitably associated with venous thrombosis, independently from the type of peripheral venous access device adopted (short peripheral cannula vs long peripheral cannula) and from the extent of dilution.

Comparison between rupture/growth risk scores and treatment recommendation scores application to aneurysmal subarachnoid hemorrhage patients: A multicenter cross-reliability assessment study.

BACKGROUND: Two score families were introduced to help clinicians about the decision-making regarding intracranial aneurysms management. The first family estimates the growth/rupture risk (GRS), whereas the second provides straightforward recommendation (RS) for treatment decisions. However, both remain poorly validated and little is known about their agreement. In this paper, we performed a retrospective concordance analysis among the two scores families through their application to a multicenter cohort of SAH patients. METHODS: Demographical, clinical and radiological data were extracted in conformance with the variables included in PHASES, UCAS, ELAPSS, Juvela's growth score (JGS), UIATS and Juvela's treatment score (JTS). Individual patients' score were calculated for both score families, and pooled data were then analyzed. RESULTS: Overall, 146 patients were included. True positive rates were: 51.4% for PHASES; 71.9% for UCAS; between 60.3% and 90.4% for JTS; and between 27.4% and 68.5% for UIATS. In patients showing UIATS unclear recommendation and low JTS score (RS), UCAS outperformed PHASES (GRS) in identifying aneurysms at higher risk of rupture. Same results we found for patients with conservative UIATS recommendation and very low JTS score. Forty-to-sixty percent of aneurysms with unclear or conservative RS recommendation would have been identified as at high risk with GRS. CONCLUSIONS: Retrospectively applied, JTS appeared outperforming UIATS in correctly recommending treatment in a higher percentage of patients. UIATS and JTS appeared agreeing more with UCAS than PHASES predictions. Around 50% of patients with unclear or conservative UIATS/JTS recommendations were been classified as at higher growth risk by ELAPSS and JGS.

Prediction of good neurological outcome in comatose survivors of cardiac arrest: a systematic review.

PURPOSE: To assess the ability of clinical examination, blood biomarkers, electrophysiology or neuroimaging assessed within 7 days from return of spontaneous circulation (ROSC) to predict good neurological outcome, defined as no, mild, or moderate disability (CPC 1-2 or mRS 0-3) at discharge from intensive care unit or later, in comatose adult survivors from cardiac arrest (CA). METHODS: PubMed, EMBASE, Web of Science and the Cochrane Database of Systematic Reviews were searched. Sensitivity and specificity for good outcome were calculated for each predictor. The risk of bias was assessed using the QUIPS tool. RESULTS: A total of 37 studies were included. Due to heterogeneities in recording times, predictor thresholds, and definition of some predictors, meta-analysis was not performed. A withdrawal or localisation motor response to pain immediately or at 72-96 h after ROSC, normal blood values of neuron-specific enolase (NSE) at 24 h-72 h after ROSC, a short-latency somatosensory evoked potentials (SSEPs) N20 wave amplitude > 4 µV or a continuous background without discharges on electroencephalogram (EEG) within 72 h from ROSC, and absent diffusion restriction in the cortex or deep grey matter on MRI on days 2-7 after ROSC predicted good neurological outcome with more than 80% specificity and a sensitivity above 40% in most studies. Most studies had moderate or high risk of bias. CONCLUSIONS: In comatose cardiac arrest survivors, clinical, biomarker, electrophysiology, and imaging studies identified patients destined to a good neurological outcome with high specificity within the first week after cardiac arrest (CA).

Gas conditioning during helmet noninvasive ventilation: effect on comfort, gas exchange, inspiratory effort, transpulmonary pressure and patient-ventilator interaction.

BACKGROUND: There is growing interest towards the use of helmet noninvasive ventilation (NIV) for the management of acute hypoxemic respiratory failure. Gas conditioning through heat and moisture exchangers (HME) or heated humidifiers (HHs) is needed during facemask NIV to provide a minimum level of humidity in the inspired gas (15 mg H2O/L). The optimal gas conditioning strategy during helmet NIV remains to be established. METHODS: Twenty patients with acute hypoxemic respiratory failure (PaO2/FiO2 < 300 mmHg) underwent consecutive 1-h periods of helmet NIV (PEEP 12 cmH2O, pressure support 12 cmH2O) with four humidification settings, applied in a random order: double-tube circuit with HHs and temperature set at 34 °C (HH34) and 37 °C (HH37); Y-piece circuit with HME; double-tube circuit with no humidification (NoH). Temperature and humidity of inhaled gas were measured through a capacitive hygrometer. Arterial blood gases, discomfort and dyspnea through visual analog scales (VAS), esophageal pressure swings (ΔPES) and simplified pressure-time product (PTPES), dynamic transpulmonary driving pressure (ΔPL) and asynchrony index were measured in each step. RESULTS: Median [IqR] absolute humidity, temperature and VAS discomfort were significantly lower during NoH vs. HME, HH34 and HH37: absolute humidity (mgH2O/L) 16 [12-19] vs. 28 [23-31] vs. 28 [24-31] vs. 33 [29-38], p < 0.001; temperature (°C) 29 [28-30] vs. 30 [29-31] vs. 31 [29-32] vs 32. [31-33], p < 0.001; VAS discomfort 4 [2-6] vs. 6 [2-7] vs. 7 [4-8] vs. 8 [4-10], p = 0.03. VAS discomfort increased with higher absolute humidity (p < 0.01) and temperature (p = 0.007). Higher VAS discomfort was associated with increased VAS dyspnea (p = 0.001). Arterial blood gases, respiratory rate, ΔPES, PTPES and ΔPL were similar in all conditions. Overall asynchrony index was similar in all steps, but autotriggering rate was lower during NoH and HME (p = 0.03). CONCLUSIONS: During 1-h sessions of helmet NIV in patients with hypoxemic respiratory failure, a double-tube circuit with no humidification allowed adequate conditioning of inspired gas, optimized comfort and improved patient-ventilator interaction. Use of HHs or HME in this setting resulted in increased discomfort due to excessive heat and humidity in the interface, which was associated with more intense dyspnea. Trail Registration Registered on clinicaltrials.gov (NCT02875379) on August 23rd, 2016.

Diaphragm thickening fraction predicts noninvasive ventilation outcome: a preliminary physiological study.

BACKGROUND: A correlation between unsuccessful noninvasive ventilation (NIV) and poor outcome has been suggested in de-novo Acute Respiratory Failure (ARF) patients. Consequently, it is of paramount importance to identify accurate predictors of NIV outcome. The aim of our preliminary study is to evaluate the Diaphragmatic Thickening Fraction (DTF) and the respiratory rate/DTF ratio as predictors of NIV outcome in de-novo ARF patients. METHODS: Over 36 months, we studied patients admitted to the emergency department with a diagnosis of de-novo ARF and requiring NIV treatment. DTF and respiratory rate/DTF ratio were measured by 2 trained operators at baseline, at 1, 4, 12, 24, 48, 72 and 96 h of NIV treatment and/or until NIV discontinuation or intubation. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the ability of DTF and respiratory rate/DTF ratio to distinguish between patients who were successfully weaned and those who failed. RESULTS: Eighteen patients were included. We found overall good repeatability of DTF assessment, with Intra-class Correlation Coefficient (ICC) of 0.82 (95% confidence interval 0.72-0.88). The cut-off values of DTF for prediction of NIV failure were < 36.3% and < 37.1% for the operator 1 and 2 (p < 0.0001), respectively. The cut-off value of respiratory rate/DTF ratio for prediction of NIV failure was > 0.6 for both operators (p < 0.0001). CONCLUSION: DTF and respiratory rate/DTF ratio may both represent valid, feasible and noninvasive tools to predict NIV outcome in patients with de-novo ARF. Trial registration ClinicalTrials.gov Identifier: NCT02976233, registered 26 November 2016.