Comparative evaluation of three total full-face masks for delivering Non-Invasive Positive Pressure Ventilation (NPPV): a bench study.

Historically, the oro-nasal mask has been the preferred interface to deliver Non-Invasive Positive Pressure Ventilation (NPPV) in critically ill patients. To overcome the problems related to air leaks and discomfort, Total Full-face masks have been designed. No study has comparatively evaluated the performance of the total Full-face masks available.The aim of this bench study was to evaluate the influence of three largely diffuse models of total Full -face masks on patient-ventilator synchrony and performance during pressure support ventilation. NPPV was applied to a mannequin, connected to an active test lung through three largely diffuse Full-face masks: Dimar Full-face mask (DFFM), Performax Full-face mask (RFFM) and Pulmodyne Full-face mask (PFFM).The performance analysis showed that the ΔPtrigger was significantly lower with PFFM (p < 0.05) at 20 breaths/min (RRsim) at both pressure support (iPS) levels applied, while, at RRsim 30, DFFM had the longest ΔPtrigger compared to the other 2 total full face masks (p < 0.05). At all ventilator settings, the PTP200 was significantly shorter with DFFM than with the other two total full-face masks (p < 0.05). In terms of PTP500 ideal index (%), we did not observe significant differences between the interfaces tested.The PFFM demonstrated the best performance and synchrony at low respiratory rates, but when the respiratory rate increased, no difference between all tested total full-face masks was reported.

Influence of total face masks design and circuit on synchrony and performance during pressure support ventilation: A bench study.

BACKGROUND: Few studies investigated the influence of the circuit applied during non-invasive ventilation (NIV) with a total face mask. The aim of this bench study was to evaluate the effects of separated inflow and outflow ports in a total face mask on patient ventilator interaction and performance during NIV through a total face mask. METHODS: A mannequin was connected to an active lung simulator. NIV was applied both via a standard total face mask (STFM) with a Y-piece connector for inflow/outflow gases and a modified total face mask (MTFM) with 2 different connectors for inflow and outflow gases. RESULTS: The MTFM showed both a significantly better patient-ventilator interaction and a significantly higher performance. The MTFM showed a significantly lower Δtrigger compared to STFM (p<0.01) and shorter value of PTPtrigger during all ventilator setting tested (p < 0.01). Significant differences in PTP 200, PTP 300, and PTP 500 were observed between the MTFM and STFM (p < 0.01) in all conditions tested. Concerning PTP 500 ideal index, in all the conditions tested, the MTFM presented higher values compared to STFM, although those differences were not statistically significant. At both RRsim and ventilator settings tested, the MTFM showed a significantly shorter Delaytrinsp and Delaytrexp compared to STFM (p < 0.01). At both RRsim tested and both ventilator settings, the MTFM showed a significantly longer Timesync compared to STFM (p < 0.01). CONCLUSIONS: The MTFM showed a significantly better patient ventilator interaction and a better ventilator performance, suggesting that this kind of total face mask design should be preferred in clinical practice.

Children and neonates anesthesia in magnetic resonance environment in Italy: an active call survey.

BACKGROUND: Pediatric anesthesia care in the Magnetic Resonance Imaging is a challenge for clinicians. The recent debate about the role of anesthetic agent on neural development, encouraged an evaluation of their actual activity in this environment. In this active call survey, the authors sought to delineate the Italian situation regarding national centers, staff involved, monitoring tools available and sedation techniques. METHODS: A complete sample of all national centers performing almost a pediatric discharge in the 2014 was obtained from Health Ministry registers. All Institutions were contacted for a prospective phone investigation and a three-section survey was fill out with the Physician in charge. A descriptive and exploratory analyzes about the organization setting of the Centers were performed. RESULTS: Among 876 Institution screened, only 106 (37%) met minimal criteria for inclusion. Children are managed by anesthesiologists in the 95% of cases, while neonates in the 54%. A dedicated nurse is present in 74% of centers. While a pulse oximetry is present in 100% of centers, the rate of prevalence of other monitoring is lower. A specific MRI-compatible ventilator is available in the 95% of Centers, but many tools are not equally homogenously distributed. Pharmacological approach is preferred in pediatric age (98%), but its use for newborns is reduced to 43%. CONCLUSIONS: We found significant heterogeneity in the daily clinical practice of sedation in MRI. Our results could be a starting point to evaluate the further evolution of approach to children and neonates in magnetic resonance setting. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04775641.

Pain Management Optimisation by an Ultrasound-Guided Analgesic Technique in Outpatients with Plantar Fasciitis during High-Energy Extracorporeal Shock Wave Therapy.

OBJECTIVE: Several studies have demonstrated the efficacy of high-energy extracorporeal shock wave therapy (HESWT) for the treatment of painful foot diseases. A crucial complication of HESWT is the appearance of pain with the subsequent interruption of the procedure. The aim of this study was the evaluation of ultrasound (US)-guided posterior tibial nerve block (PTNB) efficacy in outpatients who discontinued the first application of HESWT due to surge of moderate-severe pain. METHODS: Twenty-one patients, scheduled for HESWT due to plantar fasciitis, who interrupted the treatment for surge of pain (numeric rating scale [NRS] 5), were enrolled. After interruption of the first treatment, the patients received US-guided PTNB for every subsequent HESWT session. The same skilled anaesthesiologist performed an US-guided PTNB all the times. Once the nerve was identified, the needle was inserted and 5ml mepivacaine 1% were injected. Intensity of pain during each procedure by NRS and evaluation of patient's adherence to the treatment were detected. RESULTS: The HESWT was split into only three applications giving in average about 0.25 mJ mm-2, and all patients completed the treatment sessions. US-guided PTNB showed a significant reduction of NRS (P < 0.01) between the first HEWST without anaesthesia and the three subsequent treatments under peripheral block. CONCLUSION: US-guided PTNB resulted a valid support for the HEWST in outpatients with plantar fasciitis because it reduced the pain during the procedure, allowing to minimise the patient discomfort and to give the therapeutic doses just in three sessions.

Pressure Support Ventilation (PSV) versus Neurally Adjusted Ventilatory Assist (NAVA) in difficult to wean pediatric ARDS patients: a physiologic crossover study.

BACKGROUND: Neurally adjusted ventilatory assist (NAVA) is an innovative mode for assisted ventilation that improves patient-ventilator interaction in children. The aim of this study was to assess the effects of patient-ventilator interaction comparing NAVA with pressure support ventilation (PSV) in patients difficult to wean from mechanical ventilation after moderate pediatric acute respiratory distress syndrome (PARDS). METHODS: In this physiological crossover study, 12 patients admitted in the Pediatric Intensive Care Unit (PICU) with moderate PARDS failing up to 3 spontaneous breathing trials in less than 7 days, were enrolled. Patients underwent three study conditions lasting 1 h each: PSV1, NAVA and PSV2. RESULTS: The Asynchrony Index (AI) was significantly reduced during the NAVA trial compared to both the PSV1 and PSV2 trials (p = 0.001). During the NAVA trial, the inspiratory and expiratory trigger delays were significantly shorter compared to those obtained during PSV1 and PSV2 trials (Delaytrinspp < 0.001, Delaytrexpp = 0.013). These results explain the significantly longer Timesync observed during the NAVA trial (p < 0.001). In terms of gas exchanges, PaO2 value significantly improved in the NAVA trial with respect to the PSV trials (p < 0.02). The PaO2/FiO2 ratio showed a significant improvement during the NAVA trial compared to both the PSV1 and PSV2 trials (p = 0.004). CONCLUSIONS: In this specific PICU population, presenting difficulty in weaning after PARDS, NAVA was associated with a reduction of the AI and a significant improvement in oxygenation compared to PSV mode. TRIAL REGISTRATION: ClinicalTrial.gov Identifier: NCT04360590 "Retrospectively registered".

High-Flow Nasal Cannula Versus Standard Oxygen Therapy After Extubation in Liver Transplantation: A Matched Controlled Study.

BACKGROUND: High-flow nasal cannula (HFNC) is a key component of oxygen therapy and has largely been used in patients with acute respiratory failure. We conducted a matched controlled study with the aim to compare the preventive use of oxygen therapy delivered by HFNC versus via air-entrainment mask (standard O2) after extubation in adult subjects with liver transplantation for reducing postextubation hypoxemia. METHODS: Twenty-nine subjects with liver transplantation who received HFNC after extubation (HFNC group) were matched 1:1 with 29 controls (standard O2 group) chosen from an historical group of 90 subjects admitted to the ICU during the previous 36 months. The primary outcome of the study was the incidence of hypoxemia at 1 h and 24 h after extubation. Secondary outcomes were the rate of weaning failure, ICU length of stay, and 28-d mortality. RESULTS: The incidence of hypoxemia was not significantly different between the HFNC and standard O2 groups at 1 h and 24 h after extubation. In the HFNC group, there was a trend toward a lower rate of weaning failure compared with the standard O2 group. ICU length of stay and 28-d mortality were similar in both groups. CONCLUSIONS: Early application of HFNC in the subjects with liver transplantation did not reduce the incidence of hypoxemia after extubation compared with standard O2 and did not modify the incidence of weaning failure, ICU length of stay, and 28-d mortality in this high-risk population of subjects. (ClinicalTrials.gov registration NCT03441854.).

Effects of two different ventilation strategies on respiratory mechanics during robotic-gynecological surgery.

It is unknown which is the best ventilatory approach in patients scheduled for gynecological robotic surgery in Deep Trendelenburg position in terms of respiratory mechanics. 40 patients were enrolled: 20 patients received a standard ventilation and 20 patients received a protective ventilation. Gas exchanges, respiratory mechanics and hemodynamic parameters were recorded. No significant differences were found between the two groups in terms of respiratory mechanics. In both groups, there was a significant reduction of static compliance between Baseline and Extubation Time (p < 0.01), and a significant increase of pulmonary pressure at the same times (p < 0.01). In both groups, a significant reduction of pH (p < 0.01) and a significant increase of PaCO2 (p < 0.01) were observed between Baseline and Extubation Time. At the Extubation time, PaCO2 was significantly higher during protective ventilation compared to standard ventilation. In this particular surgical setting, a protective ventilation strategy did not improve the respiratory mechanics compared to the standard ventilation strategy and was ineffective on post-operative gas exchanges.

Comparative bench study evaluation of different infant interfaces for non-invasive ventilation.

BACKGROUND: To compare, in terms of patient-ventilator interaction and performance, a new nasal mask (Respireo, AirLiquide, FR) with the Endotracheal tube (ET) and a commonly used nasal mask (FPM, Fisher and Paykel, NZ) for delivering Pressure Support Ventilation (PSV) in an infant model of Acute Respiratory Failure (ARF). METHODS: An active test lung (ASL 5000) connected to an infant mannequin through 3 different interfaces (Respireo, ET and FPM), was ventilated with a standard ICU ventilator set in PSV. The test lung was set to simulate a 5.5 kg infant with ARF, breathing at 50 and 60 breaths/min). Non-invasive ventilation (NIV) mode was not used and the leaks were nearly zero. RESULTS: The ET showed the shortest inspiratory trigger delay and pressurization time compared to FPM and Respireo (p < 0.01). At each respiratory rate tested, the FPM showed the shortest Expiratory trigger delay compared to ET and Respireo (p < 0.01). The Respireo presented a lower value of Inspiratory pressure-time product and trigger pressure drop than ET (p < 0.01), while no significant difference was found in terms of pressure-time product at 300 and 500 ms. During all tests, compared with the FPM, ET showed a significantly higher tidal volume (VT) delivered (p < 0.01), while Respireo showed a trend toward an increase of tidal volume delivered compared with FPM. CONCLUSIONS: The ET showed a better patient-ventilator interaction and performance compared to both the nasal masks. Despite the higher internal volume, Respireo showed a trend toward an increase of the delivered tidal volume; globally, its efficiency in terms of patient-ventilator interaction was comparable to the FPM, which is the infant NIV mask characterized by the smaller internal volume among the (few) models on the market.

Remifentanil effects on respiratory drive and timing during pressure support ventilation and neurally adjusted ventilatory assist.

We assessed the effects of varying doses of remifentanil on respiratory drive and timing in patients receiving Pressure Support Ventilation (PSV) and Neurally Adjusted Ventilatory Assist (NAVA). Four incrementing remifentanil doses were randomly administered to thirteen intubated patients (0.03, 0.05, 0.08, and 0.1µg·Kg-1·min-1) during both PSV and NAVA. We measured the patient's (Ti/Ttotneu) and ventilator (Ti/Ttotmec) duty cycle, the Electrical Activity of the Diaphragm (EAdi), the inspiratory (Delaytrinsp) and expiratory (Delaytrexp) trigger delays and the Asynchrony Index (AI). Increasing doses of remifentanil did not modify EAdi, regardless the ventilatory mode. In comparison to baseline, remifentanil infusion >0.05µg/Kg-1/min-1 produced a significant reduction of Ti/Ttotneu and Ti/Ttotmec, by prolonging the expiratory time. Delaytrinsp and Delaytrexp were significantly shorter in NAVA, respect to PSV. AI was not influenced by the different doses of remifentanil, but it was significantly lower during NAVA, compared to PSV. In conclusion remifentanil did not affect the respiratory drive, but only respiratory timing, without differences between modes.

Effects of dexmedetomidine and propofol on patient-ventilator interaction in difficult-to-wean, mechanically ventilated patients: a prospective, open-label, randomised, multicentre study.

BACKGROUND: Dexmedetomidine can be used for sedation of mechanically ventilated patients and has minor respiratory effects. The aim of this study was to compare the incidence of patient-ventilator dyssynchronies during sedation with dexmedetomidine or propofol. METHODS: We conducted a multicentre, prospective, open-label, randomised clinical trial, comparing dexmedetomidine with standard propofol sedation at three intensive care units of university hospitals in Italy. Twenty difficult-to-wean patients for whom the first weaning trial had failed and who were on pressure support ventilation were randomised to receive sedation with either dexmedetomidine or propofol at a similar level of sedation (Richmond Agitation-Sedation Scale [RASS] score +1 to -2). The asynchrony index (AI) was calculated using tracings of airflow, airway pressure and electrical activity of the diaphragm sampled at 0, 0.5, 1, 2, 6, 12, 18 and 24 h. RESULTS: The mean AI was lower with dexmedetomidine than with propofol from 2 h onwards, although the two groups significantly differed only at 12 h (2.68 % vs 9.10 %, p < 0.05). No further difference was observed at 18 and 24 h. CONCLUSIONS: When sedation with propofol and dexmedetomidine was compared at similar RASS scores of patients in whom first weaning trial had failed, the AI was lower with dexmedetomidine than with propofol, and this difference was statistically significant at 12 h. These results suggest that sedation with dexmedetomidine may offer some advantages in terms of patient-ventilator synchrony.

Influence of different interfaces on synchrony during pressure support ventilation in a pediatric setting: a bench study.

BACKGROUND: In adults and children, patient-ventilator synchrony is strongly dependent on both the ventilator settings and interface used in applying positive pressure to the airway. The aim of this bench study was to determine whether different interfaces and ventilator settings may influence patient-ventilator interaction in pediatric models of normal and mixed obstructive and restrictive respiratory conditions. METHODS: A test lung, connected to a pediatric mannequin using different interfaces (endotracheal tube [ETT], face mask, and helmet), was ventilated in pressure support ventilation mode testing 2 ventilator settings (pressurization time [Timepress]50%/cycling-off flow threshold [Trexp]25%, Timepress80%/Trexp60%), randomly applied. The test lung was set to simulate one pediatric patient with a healthy respiratory system and another with a mixed obstructive and restricted respiratory condition, at different breathing frequencies (f) (30, 40, and 50 breaths/min). We measured inspiratory trigger delay, pressurization time, expiratory trigger delay, and time of synchrony. RESULTS: At each breathing frequency, the helmet showed the longest inspiratory trigger delay compared with the ETT and face mask. At f30, the ETT had a reduced Tpress. The helmet had the shortest Tpress in the simulated child with a mixed obstructive and restricted respiratory condition, at f40 during Timepress50%/Trexp25% and at f50 during Timepress80%/Trexp60%. In the simulated child with a normal respiratory condition, the ETT presented the shortest Tpress value at f50 during Timepress80%/Trexp60%. Concerning the expiratory trigger delay, the helmet showed the best interaction at f30, but the worst at f40 and at f50. The helmet showed the shortest time of synchrony during all ventilator settings. CONCLUSIONS: The choice of the interface can influence patient-ventilator synchrony in a pediatric model breathing at increased f, thus making it more difficult to set the ventilator, particularly during noninvasive ventilation. The helmet demonstrated the worst interaction, suggesting that the face mask should be considered as the first choice for delivering noninvasive ventilation in a pediatric model.

A bench study of 2 ventilator circuits during helmet noninvasive ventilation.

OBJECTIVE: To compare helmet noninvasive ventilation (NIV), in terms of patient-ventilator interaction and performance, using 2 different circuits for connection: a double tube circuit (with one inspiratory and one expiratory line) and a standard circuit (a Y-piece connected only to one side of the helmet, closing the other side). METHODS: A manikin, connected to a test lung set at 2 breathing frequencies (20 and 30 breaths/min), was ventilated in pressure support ventilation (PSV) mode with 2 different settings, randomly applied, of the ratio of pressurization time to expiratory trigger time (T(press)/T(exp-trigger)) 50%/25%, default setting, and T(press)/T(exp-trigger) 80%/60%, fast setting, through a helmet. The helmet was connected to the ventilator randomly with the double and the standard circuit. We measured inspiratory trigger delay (T(insp-delay)), expiratory trigger delay (T(exp-delay)), T(press)), time of synchrony (T(synch)), trigger pressure drop, inspiratory pressure-time product (PTP), PTP at 300 ms and 500 ms, and PTP at 500 ms expressed as percentage of an ideal PTP500 (PTP500 index). RESULTS: At both breathing frequencies and ventilator settings, helmet NIV with the double tube circuit showed better patient-ventilator interaction, with shorter T(insp-delay), T(exp-delay), and T(press); longer T(synch); and higher PTP300, PTP500, and PTP500 index (all P < .01). CONCLUSIONS: The double tube circuit had significantly better patient-ventilator interaction and a lower rate of wasted effort at 30 breaths/min.