Mean Tidal Volume Research Articles

Dynamic parameters of fluid responsiveness in the operating room : An analysis of intraoperative ventilation framework conditions.

Reliable assessment of fluid responsiveness with pulse pressure variation (PPV) depends on certain ventilation-related preconditions; however, some of these requirements are in contrast with recommendations for protective ventilation. The aim of this study was to evaluate the applicability of PPV in patients undergoing non-cardiac surgery by retrospectively analyzing intraoperative ventilation data. Intraoperative ventilation data from three large medical centers in Germany and Switzerland from January to December 2018 were extracted from electronic patient records and pseudonymized; 10,334 complete data sets were analyzed with respect to the ventilation parameters set as well as demographic and medical data. In 6.3% of the 3398 included anesthesia records, patients were ventilated with mean tidal volumes (mTV) > 8 ml/kg predicted body weight (PBW). These would qualify for PPV-based hemodynamic assessment, but the majority were ventilated with lower mTVs. In patients who underwent abdominal surgery (75.5% of analyzed cases), mTVs > 8 ml/kg PBW were used in 5.5% of cases, which did not differ between laparoscopic (44.9%) and open (55.1%) approaches. Other obstacles to the use of PPV, such as elevated positive end-expiratory pressure (PEEP) or increased respiratory rate, were also identified. Of all the cases 6.0% were ventilated with amTV of > 8 ml/kg PBW and aPEEP of 5-10 cmH2O and 0.3% were ventilated with amTV > 8 ml/kg PBW and aPEEP of > 10 cmH2O. The data suggest that only few patients meet the currently defined TV (of > 8 ml/kg PBW) for assessment of fluid responsiveness using PPV during surgery.

Comparison of Three Airway Maneuvers of Jaw Thrust, Two-Handed E-C Technique With Head in Neutral Position, and Two-Handed E-C Technique With Head Fully Extended: A Prospective, Randomized, Double-Blind Crossover Study.

Background Bag-mask ventilation is an essential life-saving skill. The E-C technique of mask holding is the most popular. In patients with suspected cervical injury, the jaw thrust maneuver is recommended instead of the E-C technique with head tilt-chin lift. Should jaw thrust fail to produce adequate chest rise, the operator is advised to switch to the E-C technique with the head tilt-chin lift maneuver with head extension as it is vital to move oxygen into the lungs. We hypothesized that the E-C clamp with the head in the neutral position without head tilt might permit adequate ventilation without producing excessive movement of the cervical spine, which in turn might translate as less strain to the cervical spine. Methods In this prospective, randomized, double-blind, crossover study, we evaluated the relative efficacy of three airway maneuvers in opening the airway in anesthetized and paralyzed adults: jaw thrust, two-handed E-C technique with head in the neutral position, and two-handed E-C technique with head fully extended. The tidal volume generated during mechanical ventilation using these three techniques was considered as the primary outcome. Seventy-two subjects were recruited for this trial and all three techniques of mask holding were performed in each of these subjects in a sequence as dictated by a randomization table. Results The jaw thrust technique provided a mean tidal volume significantly higher than the two-handed E-C technique, with the head in the neutral position (p<0.001). Similarly, the two-handed E-C technique with the head fully extended provided a mean tidal volume significantly higher than the two-handed E-C technique with the head in neutral position (p<0.011). The mean tidal volume obtained with jaw thrust and two-handed E-C technique with head fully extended were comparable (p=0.78). Conclusion The two-handed E-C technique with the head fully extended, and the jaw thrust technique both produce good and comparable tidal volumes. The two-handed E-C technique with the head in a neutral position provides adequate though lower tidal volumes as compared to the other two techniques.

The effect of pocket mask training on the self-efficacy and willingness to perform artificial respiration in cardiac arrest patients: A randomized control trial

Background: Out-of-hospital cardiac arrest due to hypoxia, it is necessary to provide adequate oxygen for correction of the cause. So, the purpose of this study was to compare the overall quality of CPR, willingness to perform ventilation using ventilation aids, and self-efficacy compared to the enlisted ventilation method (MMV) by educating the general public on pocket masks (MPV), which are respiratory aids. Methods: This study was a randomized controlled comparative study, in which 110 study subjects were listed with numbered names in the order in which they applied for training, and random numbers were named A (MMV method) and B (MPV method) in that order. Randomization generated a random number order using the SAS program, and the generated random numbers A and B were arranged from 1 to 110 in the order in which they applied for training, through this, they were classified into A groups (N = 57) and B groups (N = 53). The study subjects classified into Group A received CPR training including enlistment ventilation on April 22, 2023, and the trainees in Group B received CPR training using a ventilator on April 29, 2023. Results: The primary outcome is that the result of the comparison of ventilation quality is the mean Tidal Volume (TV) before training for MPV is 1076 ± 422, whereas the mean TV for MMV is 1015 ± 510 (p &lt; 0.05). After training, the mean tidal volume (TV) for MPV is 876ml ± 422, whereas the mean TV for MMV is 1001 ± 516, indicating that MMV resulted in a significantly higher tidal volume than the ILCO guidelines. After training, comparing the time per ventilation cycle, the MPV group showed 0.923sec ± 0.432, while the MMV group showed 1.021sec ± 0.535 (p &lt; 0.05). After completing two ventilations, it is evident that there is a delay in starting the next chest compression in the MMV group compared to the MPV group (MMV: 10.21 ± 4.112 vs. MPV: 9.88 ± 2.831, p &lt; 0.05). Conclusion: As a result of this study, the researcher recommends adding training on pocket masks when educating artificial respiration in CPR training conducted in Korea, given that the performance accuracy of pocket masks is high and the efficient ventilation rate is high.

Effects of positive end expiratory pressure during laryngeal mask airway anesthesia on respiratory parameters and abdominal pain in cataract surgery

Introduction: The purpose of this study was to evaluate the effects of positive end expiratory pressure (PEEP) on respiratory parameters and abdominal pain in patients ventilated with a laryngeal mask during cataract surgery. Methods: This clinical trial study included 80 patients in need of cataract surgery (40 in the group without PEEP and 40 in the group with PEEP at 5 cmH2O) who underwent laryngeal mask ventilation during general anesthesia. The parameters of dynamic compliance, pressure peak (Ppeak), tidal volume, SpO2, EtCO2, heart rate, non-invasive blood pressure, and abdominal pain were recorded at intervals of 1, 5, 10, and 20 minutes after the start of anesthesia and were compared between the two groups. Results: Respiratory parameters, heart rate and systolic and diastolic blood pressure were not significantly different between two groups, and only the mean tidal volume at 5, 10, and 20 minutes was significantly higher in the group without PEEP. Conclusion: Application of 5 cmH2O PEEP during ventilation with laryngeal mask in patients undergoing cataract surgery had no significant effect on improving respiratory parameters and pain in the gastric area.

First non-invasive magnetic phrenic nerve and diaphragm stimulation in anaesthetized patients: a proof-of-concept study

BackgroundMechanical ventilation has side effects such as ventilator-induced diaphragm dysfunction, resulting in prolonged intensive care unit length of stays. Artificially evoked diaphragmatic muscle contraction may potentially maintain diaphragmatic muscle function and thereby ameliorate or counteract ventilator-induced diaphragm dysfunction. We hypothesized that bilateral non-invasive electromagnetic phrenic nerve stimulation (NEPNS) results in adequate diaphragm contractions and consecutively in effective tidal volumes.ResultsThis single-centre proof-of-concept study was performed in five patients who were 30 [IQR 21–33] years old, 60% (n = 3) females and undergoing elective surgery with general anaesthesia. Following anaesthesia and reversal of muscle relaxation, patients received bilateral NEPNS with different magnetic field intensities (10%, 20%, 30%, 40%); the stimulation was performed bilaterally with dual coils (connected to one standard clinical magnetic stimulator), specifically designed for bilateral non-invasive electromagnetic nerve stimulation. The stimulator with a maximal output of 2400 Volt, 160 Joule, pulse length 160 µs at 100% intensity was limited to 50% intensity, i.e. each single coil had a maximal output of 0.55 Tesla and 1200 Volt. There was a linear relationship between dosage (magnetic field intensity) and effect (tidal volume, primary endpoint, p < 0.001). Mean tidal volume was 0.00, 1.81 ± 0.99, 4.55 ± 2.23 and 7.43 ± 3.06 ml/kg ideal body weight applying 10%, 20%, 30% and 40% stimulation intensity, respectively. Mean time to find an initial adequate stimulation point was 89 (range 15–441) seconds.ConclusionsBilateral non-invasive electromagnetic phrenic nerve stimulation generated a tidal volume of 3–6 ml/kg ideal body weight due to diaphragmatic contraction in lung-healthy anaesthetized patients. Further perspectives in critically ill patients should include assessment of clinical outcomes to confirm whether diaphragm contraction through non-invasive electromagnetic phrenic nerve stimulation potentially ameliorates or prevents diaphragm atrophy.

Incidence of Post-Operative Pulmonary Complications in Patients Undergoing Cardiac Surgery with Low Tidal Volume Ventilation

Objective: This study sought to determine if low-tidal ventilation during CPB was superior to a resting-lung strategy with no ventilation in terms of pulmonary complications following surgery. Study Design: This was a retrospective study. Place and Duration: This study was done at the Punjab Institute of cardiology, Lahore from 1st May 2021 to 1st Nov, 2022. Methodology: A total of 1348 patients were enrolled in this study following inclusion criteria. They were divided into two groups equally. SPSS version 24 was used to enter and analyzed collected data. For qualitative variables was presented in frequency(%). For quantitative variables i.e., age, height, weight, preoperative FEV1/FCV, tidal volume, PEEP, PaO2 and PaCO2 mean ±SD was calculated. Chi-square was applied to compare post-operative outcomes between the groups. P-value of &lt;0.05 was taken as significant. Results: The mean age of the cases in Group A was 55 ± 9.08 while in Group B was 56 ± 9.19. There were 75% male and 25% females in Group A while 84% male and 16% females in Group B. In our data there were 67% diabetic and 59% smokers in Group A however 62% diabetic and 58% smokers were enrolled in Group B. Mean tidal volume given to Group A was 8.5 ± 1.8 while in Group B was 7.5 ± 1.3. Peak respiratory pressure in Group A was 18 and in Group B was 16. Mean perfusion time, cross clamp time and anesthesia duration was significant between the groups p-value 0.01. Mean tidal volume given to Group A was 8.5 ± 1.8 while in Group B was 7.5 ± 1.3. Peak respiratory pressure in Group A was 18 and in Group B was 16. Mean perfusion time, cross clamp time and anesthesia duration was significant between the groups p-value 0.01. Conclusion: This study found that continuing low tidal volume ventilation was not superior to no ventilation during CPB in terms of the rate of reintubation, pleural effusion, and pulmonary congestion, although there was a significant difference between pneumonia, atelectasis, and prolong ventilation. Keywords: PEEP, CPB, FEV1/FCV ,Pulmonary Complications, Ventilation, Tidal Volume

A pilot study to evaluate the safety and efficacy of automated mechanical respiratory aid device

Background: High burden of morbidity and mortality due to respiratory illnesses was witnessed during the COVID-19 pandemic. We developed a portable automated mechanical respiratory assist device (RespirAID R20) that delivers Intermittent Positive Pressure Ventilation by mechanically compressing a Bag Valve Mask. The objective of the study is to evaluate the safety and efficacy of the RespirAID R20, a mechanical ventilation device in post-operative care patients. Method: This pilot study enrolled five subjects at Yenepoya Medical College Hospital, India. Post-operative subjects were transferred from the Mindray Synovent E3 (standard ventilator) to the RespirAID R20 for 3 hours. Ventilator and physiologic parameters were recorded and compared. Result: All patients maintained normal blood pressure, heart rate, and heart rhythm. The delivered mean tidal volume (VT) and peak inspiratory pressure (PIP) was 419.64 +/- 11 ml and 20 +/- 2 cmH2O, which remained within the initial set range of 428 +/- 12 ml and 24 +/- 2 cmH2O throughout the study duration. Arterial blood gas (ABG) parameters during RespirAID R20, except PaO2, were within the normal range. PaO2 levels were greater than 300 mm Hg during the first four hours (323 +/- 163 mmHg and 344 +/- 97 mmHg). Conclusion: The findings of this study suggests that RespirAID R20 may be an alternative device in providing respiratory assistance to sedated and intubated adult patients in the postoperative period. Additional studies are required to evaluate other possible applications of the RespirAID R20. Keywords: RespirAID R20, ABG parameters, mechanical ventilation, respiratory assist

Elevated Driving Pressure and Elastance Does Not Increase In-Hospital Mortality Among Obese and Severely Obese Patients With Ventilator Dependent Respiratory Failure.

To determine if driving pressure (DP) and total respiratory system elastance (Ers) differ among normal/overweight (body mass index [BMI] < 30 kg/m2), obese, and severely obese ventilator-dependent respiratory failure (VDRF) patients and if there any associations with clinical outcomes. Retrospective observational cohort study during 2016-2018 at two tertiary care academic medical centers using electronic health record data from the first 2 full days of mechanical ventilation. The cohort was stratified by BMI classes to measure median DP, time-weighted mean tidal volume, plateau pressure, and Ers for each BMI class. Mechanically ventilated patients in medical and surgical ICUs. Primary outcome and effect measures included relative risk of in-hospital mortality, ventilator-free days, ICU length of stay, and hospital length of stay with multivariable adjustment. The cohort included 3,204 patients with 976 (30.4%) and 382 (11.9%) obese and severely obese patients, respectively. Severe obesity was associated with a DP greater than or equal to 15 cm H2O (relative risk [RR], 1.51 [95% CI, 1.26-1.82]) and Ers greater than or equal to 2 cm H2O/(mL/kg) (RR, 1.31 [95% CI, 1.14-1.49]). Despite elevated DP and Ers, there were no differences in in-hospital mortality, ventilator-free days, or ICU length of stay among all three groups. Despite higher DP and ERS among obese and severely obese VDRF patients, there were no differences in in-hospital mortality or duration of mechanical ventilation, suggesting that DP has less prognostic value in obese and severely obese VDRF patients.

Safety and Considerations of the Anaesthetic Management during Bronchoscopic Lung Volume Reduction Treatments

Background: Different bronchoscopic lung volume reduction approaches are available for a select group of patients with advanced COPD. General anaesthesia is the recommended method of sedation during these procedures. However, this patient population is at an increased risk of anaesthetic complications, and the best approach to general anaesthesia and mechanical ventilation is unknown. Objectives: The aims of this study were to describe the anaesthetic management techniques used during bronchoscopic lung volume reduction procedures and to investigate the number of anaesthesia-related events. Methods: Data were retrospectively collected from all endobronchial valve and lung volume reduction coil procedures performed between January 2018 and March 2020 in our hospital. Primary outcomes measures were anaesthetic technique including airway management; ventilation mode and settings; and the incidence of anaesthesia-related events, classified as catastrophic, severe, significant, or moderate. Results: 202 procedures were included. One procedure was performed under procedural sedation, 198 (98%) under general anaesthesia with endotracheal intubation, and 3 (1.5%) under general anaesthesia with laryngeal mask airway. Volume-controlled ventilation was used in 64% of the procedures and pressure-controlled in 36%. Patients were ventilated with a median respiration rate of 9.9 (IQR: 9.6–10.6) breaths per minute, mean tidal volume of 5.8 ± 1.4 mL/kg, and median inspiratory to expiratory (I:E) ratio of 1:2.8 (IQR: 1:2.1–1:3.2). No catastrophic anaesthesia-related events were observed. Hypotension was the most observed anaesthesia-related event. Conclusions: Despite the presence of advanced COPD, general anaesthesia and mechanical ventilation are well tolerated by patients undergoing endobronchial valve or lung volume reduction coil treatment. This is presumably strongly linked to the strict selection criteria. Other important considerations are using a low respiratory rate, low tidal volume, and high I:E ratio.

POSITIVE END-EXPIRATORY PRESSURE (PEEP) INDEX: A NOVEL, BETTER DISCRIMINATION MARKER THAN PAO2/FIO2 FOR RESCUE MEASURES IN COVID-RELATED ARDS

POSITIVE END-EXPIRATORY PRESSURE (PEEP) INDEX: A NOVEL, BETTER DISCRIMINATION MARKER THAN PAO2/FIO2 FOR RESCUE MEASURES IN COVID-RELATED ARDS

Dietary nitrate supplementation enhances heavy load carriage performance in military cadets.

To determine the effects of dietary nitrate (NO3-) supplementation on physiological responses, cognitive function, and performance during heavy load carriage in military cadets. Ten healthy males (81.0 ± 6.5kg; 180.0 ± 4.5cm; 56.2 ± 3.7ml·kg·min-1 VO2max) consumed140mL·d-1 of beetroot juice (BRJ; 12.8mmol NO3-) or placebo (PL) for six d preceding an exercise trial, which consisted of 45min of load carriage (55% body mass) at 4.83km·h-1 and 1.5% grade, followed by a 1.6-km time-trial (TT) at 4% grade. Gas exchange, heart rate, and perceptual responses were assessed during constant-load exercise and the TT. Cognitive function was assessed immediately prior to, during, and post-exercise via the psychomotor vigilance test (PVT). Post-TT HR (188 ± 7.1 vs. 185 ± 7.4; d = 0.40; p = 0.03), mean tidal volume (2.15 ± 0.27 vs. 2.04 ± 0.23; p = 0.02; d = 0.47), and performance (770.9 ± 78.2s vs. 809.8 ± 61.4s; p = 0.03; d = 0.63) were increased during the TT with BRJ versus PL. There were no effects of BRJ on constant-load gas exchange or perceptual responses, and cognitive function was unchanged at all time points. BRJ supplementation improves heavy load carriage performance in military cadets possibly as a result of attenuated respiratory muscle fatigue, rather than enhanced exercise economy.

Comparison of Effectiveness of CE Technique and Jaw Thrust Technique for Mask Ventilation on Apneic Anesthetized Adults: A Randomized Controlled Trial.

The two most common techniques for mask ventilation are CE and jaw thrust (JT) technique. However, few studies have validated their efficiency in terms of tidal volume (TV). This study aimed to compare the effectiveness of the CE technique and JT technique during pressure-controlled ventilation (PCV) by the mean of returned TV on apneic anesthetized adults. This was a prospective, randomized cross over study. This study was conducted in a tertiary care hospital. Ethical Committee approval from our institution was taken (ss-1/EC 049/2017) and was registered in Clinical Trials Registry of India (CTRI/2018/04/012958). Sixty-five American Society of Anesthesiologists Physical Status classes I and II adult patients were enrolled in the study. After induction and muscle relaxation, mask ventilation was performed with CE and JT technique on PCV mode (Pinsp 15 cm H2O, respiratory rate 15) for 1 min each. The mean of returned TV of last 12 breaths, gastric insufflation, audible mask leak, and operator comfort in each technique were compared. Statistical software namely IBM SPSS 22.0 and R environment version 3.2.2 (IBM Corp. SPSS Statistics for Windows, Version 22.0. Armonk, NY, USA) were used for data analysis. Microsoft Excel was used to generate graphs and tables. Data were expressed as mean ± standard deviation for continuous variables and number (%) for categorical variables. Student's t-test (two tailed, independent) was used to find the significance of the study parameters on a continuous scale. Chi-square/Fisher's exact test was used to find the significance of the study parameters on a categorical scale between two or more groups. There was a significant increase in mean TV generated by JT technique over CE technique (591.46 ± 140.27 mL vs. 544.59 ± 159.08 mL; P < 0.001). Gastric insufflation (12.9% vs. 14.5%) and mask leak (11.3% vs. 38.7%) were more in CE technique. Operator comfort (79% vs. 19.4%) was more in JT technique. A two-handed JT technique is more effective than a one-handed CE technique for mask ventilation in apneic anesthetized adults.

Facemask ventilation and vocal cord angle following neuromuscular blockade: a prospective observational study.

Numerous studies support the idea that neuromuscular blockade facilitates facemask ventilation after induction of anaesthesia. Although improved airway patency or pulmonary compliance and a resolution of laryngospasm have been suggested as possible causes, the exact mechanism remains unclear. We aimed to assess whether neuromuscular blockade improves facemask ventilation and to clarify whether this phenomenon is associated with the vocal cord angle. This prospective observational study included patients aged between 20 and 65 years scheduled for elective surgery under general anaesthesia. After induction of anaesthesia, patients' lungs were ventilated with pressure-controlled ventilation using a facemask. During facemask ventilation, a flexible bronchoscope was inserted through a self-sealing diaphragm at the elbow connector attached to the facemask and breathing circuit and positioned to allow a continuous view of the vocal cords. The mean tidal volume and vocal cord angle were measured before and after administration of neuromuscular blocking drugs. Of 108 patients, 100 completed the study. Mean (SD) tidal volume ((11.0 (3.9) ml.kg-1 vs. 13.6 (2.6) ml.kg-1 ; p < 0.001) and mean (SD) vocal cord angle (17° (10°) vs. 26° (5°); p < 0.001) increased significantly after neuromuscular blockade. The proportional increase in mean tidal volume after neuromuscular blockade was positively correlated with vocal cord angle (Spearman's ρ = 0.803; p < 0.001). In conclusion, neuromuscular blockade facilitated facemask ventilation, and the improvement was correlated with further opening of the vocal cords.

Rocuronium versus saline for effective facemask ventilation during anesthesia induction: a double-blinded randomized placebo-controlled trial

BackgroundMask ventilation progressively improves after loss of consciousness during anesthesia induction possibly due to progression of muscle paralysis. This double-blinded randomized placebo-controlled study aimed to test a hypothesis that muscle paralysis improves mask ventilation during anesthesia induction.MethodsForty-four adults patients including moderate to severe obstructive sleep apnea undergoing scheduled surgeries under elective general anesthesia participated in this study. Randomly-determined test drug either rocuronium or saline was blinded to the patient and anesthesia provider. One-handed mask ventilation with an anesthesia ventilator providing a constant driving pressure and respiratory rate (15 breaths per minute) was performed during anesthesia induction, and changes of capnogram waveform and tidal volume were assessed for one minute. The needed breaths for achieving plateaued-capnogram (primary variable) within 15 consecutive breaths were compared between the test drugs.ResultsMeasurements were successful in 38 participants. Twenty-one and seventeen patients were allocated into saline and rocuronium respectively. The number of breaths achieving plateaued capnogram did not differ between the saline (95% C.I.: 6.2 to 12.8 breaths) and rocuronium groups (95% C.I.: 5.6 to 12.7 breaths) (p = 0.779). Mean tidal volume changes from breath 1 was significantly greater in rocuronium group than saline group (95% C.I.: 0.56 to 0.99 versus 3.51 to 4.53 ml kg-IBW−1, p = 0.006). Significantly more patients in rocuronium group (94%) achieved tidal volume greater than 5 mg kg-ideal body weight−1 within one minute than those in saline group (62%) (p = 0.026). Presence of obstructive sleep apnea did not affect effectiveness of rocuronium for improvement of tidal volume during one-handed mask ventilation.ConclusionsUse of rocuronium facilitates tidal volume improvement during one-handed mask ventilation even in patients with moderate to severe obstructive sleep apnea.Trial registrationThe clinical trial was registered at (05/12/2013, UMIN000012495): https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000014515

Prone Positioning Under ECMO: A Retrospective Cohort of 34 Patients

<h3>Purpose</h3> Extracorporeal Membrane Oxygenation (ECMO) become standard therapy for refractory hypoxemia (veno-venous (VV)) and circulatory failure (veno-arterial (VA)). However, severe hypoxemia may persist in some patients under ECMO. Prone position (PP) has been shown to have a benefit on oxygenation in patients with acute respiratory distress syndrome. We performed a retrospective study to evaluate the change of oxygenation and the risks involved in positioning patients under ECMO in PP. <h3>Methods</h3> All patients who underwent PP under ECMO from August 2014 to December 2020 were included. PP was performed on two criteria: refractory hypoxemia defined by a P/F<80mmHg despite 100% FiO2 on ventilator and ECMO or persistent hypoxemia defined by a need to maintained FiO2 ≥80% on ECMO with posterior pulmonary condensations on CT scan. Ventilatory and ECMO parameters and PP-related complications were collected. <h3>Results</h3> From 556 patients under ECMO, 34 (6.1%) (median age 54 years) were included for 87 PP procedures (2.5 +/-2.4 sessions per patient). ECMO was VA for 6 patients, VV for 27 patients and VAV for one patient. 19 patients were placed in PP for refractory hypoxemia and 15 for persistent hypoxemia. Mean tidal volume was 4.5mL/kg +/-1.7, median positive end-expiratory pressure at 10 cmH20 (IQR 10-15), respiratory rate at 20/min (IQR 18-28). Mean PP session duration was 18 h +/-4.2. Median time from ECMO placement to first PP was 7 days (IQR 4-10). PP procedures resulted in a significant improvement in oxygenation, with increasing P/F_ECMO ratio from 92.6 to 133.2 on average (p<0.0001). Concomitantly the ventilator FiO2 decreased from 65% to 55% (p<0.0001).The most frequent complication was the presence of bedsores of the face and trunk (6 patients). The other complications reported were: 1 cardio respiratory arrest due to tamponade, 1 pump thrombosis, 1 displacement of limb reperfusion cannula, 1 tracheostomy decanulation. No ECMO decanulation occurred. At discharge, 9 of 34 patients with PP (26%) had died compared to 237 on 522 patients under ECMO without PP(45.4%) (p=0.033). <h3>Conclusion</h3> PP in hypoxemic patients under ECMO is effective for improving oxygenation. A beneficial effect on mortality is also suggested. In an expert center, less than 20% of patients experienced bedsores and 12% may suffer from severe complications requiring urgent treatment.

Clinical characteristics, respiratory management, and determinants of oxygenation in COVID-19 ARDS: A prospective cohort study.

PurposeTo identify determinants of oxygenation over time in patients with COVID-19 acute respiratory distress syndrome (ARDS); and to analyze their characteristics according to Berlin definition categories.Materials and methodsProspective cohort study including consecutive mechanically ventilated patients admitted between 3/20/2020–10/31/2020 with ARDS. Epidemiological and clinical data on admission; outcomes; ventilation, respiratory mechanics and oxygenation variables were registered on days 1, 3 and 7 for the entire population and for ARDS categories.Results1525 patients aged 61 ± 13, 69% male, met ARDS criteria; most frequent comorbidities were obesity, hypertension, diabetes and respiratory disease. On admission, 331(21%), 849(56%) and 345(23%) patients had mild, moderate and severe ARDS; all received lung-protective ventilation (mean tidal volumes between 6.3 and 6.7 mL/kg PBW) and intermediate PEEP levels (10–11 cmH2O). PaO2/FiO2, plateau pressure, static compliance, driving pressure, ventilation ratio, pH and D-dimer >2 mg/L remained significantly different among the ARDS categories over time. In-hospital mortality was, respectively, 55%, 58% and 70% (p < 0.000). Independent predictors of changes of PaO2/FiO2 over time were BMI; preexistent respiratory disease; D-dimer >2 mg/L; day 1-PEEP, and day 1-ventilatory ratio.ConclusionHypoxemia in patients with COVID-19-related ARDS is associated with comorbidities, deadspace and activated coagulation markers, and disease severity—reflected by the PEEP level required.

Control of air leakage during pleurectomy/decortication by the ventilation and anchoring method.

We previously established a novel method of lung repair called the ventilation and anchoring (V/A) method. We evaluated the usefulness of the V/A method for controlling air leakage during pleurectomy/decortication (P/D). For this study, we enrolled patients with malignant pleural mesothelioma (MPM) who planned to receive P/D. Our lung repair method involves (1) suturing lung parenchyma for an apparent injured lesion and (2) coating the lung parenchyma with fibrin glue (FG) using the V/A method. The tidal volume (TV) was measured under pressure-controlled ventilation in the ipsilateral-affected lung 10 times at the following four points: after thoracotomy, at completion of visceral pleurectomy, after suturing lung parenchyma, and 5min after coating with FG. The primary endpoint was the mean TV (mTV) change, and the secondary endpoints were the duration of air leakage and incidence of pleurodesis. Between April 2014 and April 2016, 25 patients of the 29 consecutive patients enrolled were eligible. The mTV significantly decreased after completion of visceral pleurectomy but significantly increased after repair of the lung parenchyma, especially after coating with FG. The median duration of postoperative air leakage was 4days (range: 2-19days). Postoperative air leakage > 7days was observed in 11 (44%) patients. Of these 11 patients, 6 received pleurodesis; however, no further revision was needed. Significant increases in TV were observed after coating with FG via the V/A method during P/D. Coating with FG using the V/A method can contribute to a reduction in air leakage during P/D.

Lung Ultrasound and Electrical Impedance Tomography During Ventilator-Induced Lung Injury.

Lung damage during mechanical ventilation involves lung volume and alveolar water content, and lung ultrasound (LUS) and electrical impedance tomography changes are related to these variables. We investigated whether these techniques may detect any signal modification during the development of ventilator-induced lung injury (VILI). Experimental animal study. Experimental Department of a University Hospital. Forty-two female pigs (24.2 ± 2.0 kg). The animals were randomized into three groups (n = 14): high tidal volume (TV) (mean TV, 803.0 ± 121.7 mL), high respiratory rate (RR) (mean RR, 40.3 ± 1.1 beats/min), and high positive-end-expiratory pressure (PEEP) (mean PEEP, 24.0 ± 1.1 cm H2O). The study lasted 48 hours. At baseline and at 30 minutes, and subsequently every 6 hours, we recorded extravascular lung water, end-expiratory lung volume, lung strain, respiratory mechanics, hemodynamics, and gas exchange. At the same time-point, end-expiratory impedance was recorded relatively to the baseline. LUS was assessed every 12 hours in 12 fields, each scoring from 0 (presence of A-lines) to 3 (consolidation). In a multiple regression model, the ratio between extravascular lung water and end-expiratory lung volume was significantly associated with the LUS total score (p < 0.002; adjusted R2, 0.21). The variables independently associated with the end-expiratory difference in lung impedance were lung strain (p < 0.001; adjusted R2, 0.18) and extravascular lung water (p < 0.001; adjusted R2, 0.11). Data suggest as follows. First, what determines the LUS score is the ratio between water and gas and not water alone. Therefore, caution is needed when an improvement of LUS score follows a variation of the lung gas content, as after a PEEP increase. Second, what determines the end-expiratory difference in lung impedance is the strain level that may disrupt the intercellular junction, therefore altering lung impedance. In addition, the increase in extravascular lung water during VILI development contributed to the observed decrease in impedance.

Use of a novel pedal‐operated compressor is non‐inferior to the use of a standard hand‐compressed bag‐valve mask

BackgroundThe standard bag‐valve mask (BVM) used universally requires that a single healthcare practitioner affix the mask to the face with 1 hand while compressing a self‐inflating bag with the second hand. Studies have demonstrated that creating a 2‐handed seal (with 2 healthcare practitioners) is superior. Our study aims to assess the efficacy of a novel single‐practitioner BVM device that uses a foot pedal as the bag compressor, allowing both hands to be available for the seal to facilitate delivery of appropriate tidal volumes during single‐practitioner resuscitation.MethodsThis was a prospective, randomized, cross‐over study. Participants with various BVM ventilation experience performed 2 minutes of metronome‐guided BVM ventilation using a standard BVM and the pedal‐operated compressor on a high‐fidelity simulation mannequin. Analysis examining differences in mean tidal volume delivered was conducted using a regression model that adjusted for covariates. A secondary analysis using a series of Wilcoxon tests was conducted to compare differences in the additional out‐of‐range sensed breaths metrics to compare differences by prior BVM ventilation experience.ResultsA total of 58 subjects participated. The pedal‐operated compressor unadjusted mean tidal volume delivered was 446.5 mL (95% confidence interval [CI], 425.9–467.1) compared with 340.6 mL (95% CI, 312.2–369.0) by standard BVM (mean change, 105.9 mL [95% CI, 71.2–140.6]; P < .001). When modeling a generalized estimation equation regression model, standard BVM ventilation provided a mean difference of 105.9 mL less than pedal‐operated compressor ventilation after adjusting for covariates (P = 0.01). For the secondary outcome, the pedal‐operated compressor did have a significantly lower median number of out‐of‐range breaths (median, 3; interquartile range [IQR], 1–11.5) compared with the standard device (median, 13.5; IQR, 6–19; P < 0.001).ConclusionsUse of a novel pedal‐operated compressor may allow a single healthcare practitioner, regardless of prior experience, to deliver consistent, appropriate tidal volumes with more ease compared with the standard BVM during manual respiratory resuscitation.

Contemporary N2 and SF6 multiple breath washout in infants and toddlers with cystic fibrosis.

Multiple breath washout (MBW) is used for early detection of cystic fibrosis (CF) lung disease, with SF6 MBW commonly viewed as the reference method. The use of N2 MBW in infants and toddlers has been questioned for technical and physiological reasons, but a new correction of the N2 signal has minimized the technical part. The present study aimed to assess the remaining differences and the contributing mechanisms for the differences between SF6 and N2 MBW,corrected-such as tidal volume reduction during N2 washout with pure O2 . This was a longitudinal multicenter cohort study. SF6 MBW and N2 MBW were performed prospectively at three CF centers in the same visits on 154 test occasions across 62 children with CF (mean age: 22.7 months). Offline analysis using identical algorithms to the commercially available program provided outcomes of N2,original and N2,corrected for comparison with SF6 MBW. Mean functional residual capacity, FRCN2,corrected was 14.3% lower than FRCN2, original , and 1.0% different from FRCSF6 . Lung clearance index, LCIN2,corrected was 25.2% lower than LCIN2,original , and 7.3% higher than LCISF6 . Mean (SD) tidal volume decreased significantly during N2 MBWcorrected , compared to SF6 MBW (-13.1 ml [-30.7; 4.6], p < 0.0001, equal to -12.0% [-25.7; 1.73]), but this tidal volume reduction did not correlate to the differences between LCIN2,corrected and LCISF6 . The absolute differences in LCI increased significantly with higher LCISF6 (0.63/LCISF6 ) and (0.23/LCISF6 ), respectively, for N2,original and N2,corrected , but the relative differences were stable across disease severity for N2,corrected , but not for N2,original . Only minor residual differences between FRCN2,corrected and FRCSF6 remained to show that the two methods measure gas volumes very similar in this age range. Small differences in LCI were found. Tidal volume reduction during N2 MBW did not affect differences. The corrected N2 MBW can now be used with confidence in young children with CF, although not interchangeably with SF6 .