Positive End-expiratory Pressure Research Articles

Oral Ibuprofen versus Placebo for Management of Patent Ductus Arteriosus in Preterm infants: A Double Blinded, Randomized Controlled Trial

Abstract Background A consensus on the management of patent ductus arteriosus (PDA) in premature neonates remains indefinable. Conservative PDA treatment is based on the premise that in most preterms PDAs spontaneously close before discharge. Ibuprofen has been used for treating PDA, however, no clear guidelines for management have been suggested. Aim of Work The aim of this work is to compare the effect of oral ibuprofen versus placebo on PDA closure in preterm infants less than 34 weeks’ gestation. Methodology This study was conducted on 80 preterm neonates with gestational age ≤ 34 weeks with a hemodynamically significant PDA. They were randomized into a medical treatment group (n = 40) and a placebo group (n = 40). Both groups received conservative PDA therapy in the form of fluid restriction, positive end-expiratory pressure, and/or diuretics. The medical treatment group received oral ibuprofen (at an initial dose of 10 mg/kg/day, followed by 5 mg/kg/day for the next 2 days) and the placebo group received an oral placebo. The open-label option and an extended oral ibuprofen therapy (an offered or a repeated course with the same dose) were only offered if there are concerns over a poor patient condition that was attributed to persistent PDA and only after meeting certain criteria like signs of pulmonary hyperperfusion and/or systemic hypoperfusion. Echocardiography was done on day 1 of recruitment (48-72 hours of age) and was followed up till discharge. The patients were followed up for adverse effects of ibuprofen by serum creatinine and total serum bilirubin after the first course of treatment. Results There was no significant difference in PDA closure rate following the first ibuprofen course (62.5% in the ibuprofen treated group vs 65% in the placebo group, p > 0.05). At discharge time (mean 13.5 days in the ibuprofen group, 14 days in the placebo group), a closure rate of 75% was achieved in both groups, respectively. There was no significant difference in initial serum creatinine levels between the two groups either on day 1 of recruitment or after the first course of the intervention, p > 0.05, respectively. Meanwhile, serum creatinine significantly decreased in both groups after treatment (p-value <0.001, respectively). Also, there was no difference between the two groups in serum bilirubin either on day 1 of recruitment or after the first course of treatment, p > 0.05, respectively. Conclusion Conservative treatment is not inferior to oral ibuprofen therapy in the management of PDA. Oral ibuprofen does not elevate serum creatinine levels or cause hyperbilirubinemia.

The impact of positive end-expiratory pressure on right ventricular function in patients with moderate-to-severe ARDS: a prospective paired-design study.

To determine the effects of varying positive end-expiratory pressures (PEEPs) on right ventricular function, hemodynamics, oxygenation, and the incidence of acute cor pulmonale (ACP) in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). This prospective paired-design study involved patients with moderate-to-severe ARDS in the ICU. Participants received lung-protective ventilation and hemodynamic monitoring. During the study, mechanical ventilation was administered with PEEPs of 5 cmH2O, 10 cmH2O, and 15 cmH2O, while maintaining an end-inspiratory plateau pressure ≤ 30 cmH2O. Various assessments, including transthoracic echocardiography, cardiac output measurement, and blood gas analysis, were conducted at baseline and after 1 h of ventilation at each PEEP. Subsequently, variations in ventilation oxygenation, echocardiographic parameters, and hemodynamic indicators under different PEEPs were analyzed to explore the potential effects of PEEP on right ventricular function and hemodynamics, as well as the incidence of ACP. A total of 317 ARDS patients were screened. Among them, 104 met the diagnostic criteria for moderate-to-severe ARDS, and 52 completed the study. The baseline PEEP of these 52 participants, acquired before commencement, was 11.5 ± 1.7 cmH2O, and the incidence of ACP was 25.0% (13/52). Intensive care unit mortality, overall hospital mortality, and 28-day mortality rates were 19.2% (10/52), 21.2% (11/52), and 32.7% (17/52), respectively. During the study, ACP incidences at PEEPs of 5 cmH2O, 10 cmH2O, and 15 cmH2O were 17.3% (9/52), 21.2% (11/52), and 38.5% (20/52), respectively. Meanwhile, the PaO2/FiO2 ratio improved with increasing PEEP, reaching 162.0 (140.9, 174.0), 171.0 (144.0, 182.0), and 176.5 (151.0, 196) mmHg at PEEPs of 5 cmH2O, 10 cmH2O, and 15 cmH2O, respectively. In addition, higher PEEPs were associated with a slight increase in PaCO2, showing statistically significant differences compared to moderate and low PEEPs. Compared to a PEEP of 5 cmH2O or 10 cmH2O, right ventricular function exhibited substantial changes at 15 cmH2O PEEP, manifested as increased pulmonary artery systolic pressure, enlarged right ventricular end-diastolic area, and decreased tricuspid annular plane systolic excursion, all with significant differences. Conversely, variations in left ventricular end-diastolic area and ejection fraction were not statistically significant. In terms of hemodynamics, increasing PEEP resulted in a decline in cardiac index (CI), with statistically significant differences between different PEEPs. Specifically, compared to the value at a PEEP of 5 cmH2O, the CI at a PEEP of 15 cmH2O decreased by 14.3% (2.63 [2.20, 2.95] vs. 3.07 [2.69, 3.67], p < 0.001). The decline in the stroke volume index with PEEP was more obvious (22.1 [18.4, 27.1] vs. 27.0 [24.2, 33.0], p < 0.001), reaching 18.1%. Additionally, both end-diastolic volume index and extravascular lung water index decreased significantly with increasing PEEP, while the pulmonary vascular permeability index remained unaffected. Different PEEPs can affect the incidence of ACP in patients with moderate-to-severe ARDS. High PEEP improves oxygenation and reduces extravascular lung water without significantly affecting the pulmonary vascular permeability index and left ventricular systolic function. Nevertheless, it can cause right ventricular dilation, as well as substantial declines in right ventricular systolic function and CI, thereby causing ACP.

Incremental Application of Positive End-Expiratory Pressure for the Evaluation of Atelectasis During RP-EBUS and Bronchoscopy (I-APPEAR).

CT-to-body divergence-described as the difference between preprocedural CT scans and intraprocedural lung architecture-is a significant barrier to improving diagnostic yield during navigational bronchoscopy. A major proposed contributor to CT-to-body divergence is the development of atelectasis, which can confound visualization of peripheral lung lesions via radial probe endobronchial ultrasound (RP-EBUS). High positive end-expiratory pressure (PEEP) ventilatory strategies have been used to decrease atelectasis, allowing the lesion to re-APPEAR on intraprocedure imaging. However, standardized PEEP levels may not be appropriate for all patients due to hemodynamic and ventilatory impacts. We performed a multicenter, prospective observational study in which patients were imaged with RP-EBUS under general anesthesia to determine if subsegmental atelectasis would resolve as incremental increases in PEEP were applied. Resolution of atelectasis was based on the transition from a non-aerated pattern to an aerated appearance on RP-EBUS. RP-EBUS images were reviewed by 3 experienced operators to determine correlation. Forty-three patients underwent RP-EBUS examination following navigational bronchoscopy. Thirty-seven patients underwent incremental PEEP application and subsequent RP-EBUS imaging. Atelectasis was determined to have resolved in 33 patients (88.2%) following increased PEEP. The intraclass correlation coefficient between reviewers was 0.76. A recruitment maneuver was performed in 7 (16.3%) patients after atelectasis persisted at maximal PEEP. Atelectasis was not identified in the examined subsegments in 6 (10.8%) patients despite zero PEEP. RP-EBUS is an effective tool to monitor what pressure atelectasis within a lung segment has resolved with increasing levels of PEEP.

Optimal Positive End-expiratory Pressure Levels in Tuberculosis-associated Acute Respiratory Distress Syndrome.

The objective is to assess lung compliance and identify the optimal positive end-expiratory pressure (PEEP) levels in patients with tuberculosis-associated Acute Respiratory Distress Syndrome (TB-ARDS) compared to non-TB-ARDS patients. This observational case-control study utilized electrical impedance tomography to evaluate lung mechanics in 20 TB-ARDS and 20 non-TB-ARDS patients. Participants underwent PEEP titration from 23 to 5 cm H2O in 2 cm H2O decrements. Lung compliance and the rates of hyperdistention and collapse were assessed at each PEEP level. Delta impedance values showed higher amounts in a PEEP range of 11-17 cm H2O and in patients with TB-ARDS (P > 0.05). In addition, both hyperdistention and collapse rates were nonsignificantly higher in TB-ARDS patients (P > 0.05), and the compromised levels of hyperdistention and collapse rates were at 15-17 cm H2O, indicating the most favorable PEEP level. The observed patterns of hyperdistention and collapse rates across various PEEP levels provide valuable insights into the susceptibility of TB-ARDS patients to barotrauma. Notably, the identified optimal PEEP range between 15 and 17 cm H2O may guide ventilator management strategies in mitigating both hyperdistention and collapse; nonetheless, due to the high variability of lung compliances within groups, we strongly recommend individualized consideration for tailored respiratory support and evaluation.

Evaluation of the Effectiveness of Adjunctive N-Acetylcysteine Nebulizer in Critically Ill Patients with COVID-19: A Pre-post Study

Abstract Background: The uncontrolled inflammatory immune response associated with SARS-CoV-2 can lead to cytokine storm and acute respiratory distress syndrome. N-Acetylcysteine (NAC) nebulizer therapy is being considered as a potential treatment option in coronavirus disease 2019 (COVID-19) patients due to its mucolytic, antioxidant, anti-inflammatory, and antiviral properties. However, the use of NAC in critically ill COVID-19 patients has not been extensively studied. Therefore, a study was conducted to evaluate the effectiveness of adjunctive NAC on respiratory function in critically ill patients with COVID-19. Materials and Methods: A pre-post retrospective study included critically ill patients with COVID-19 admitted to the intensive care units and received NAC nebulizers between March 2020 and July 2021. The primary outcome was to assess the PaO2/FiO2 (P/F) ratio differences before and after NAC administration. Other outcomes were considered secondary, such as the positive end-expiratory pressure (PEEP), tidal volume, and invasive mechanical ventilation (MV) status. A paired t test or Wilcoxon signed-rank test was used based on the data distribution. A P value of &lt;0.05 was considered statistically significant. Results: The results revealed that a total of 1081 critically ill patients with COVID-19 were screened during the study period, and only 44 were included. Most of the patients were male (75%) with a median age of 58 years (range = 48.5–76.5 years). Before NAC initiation, the median P/F ratio was 136.55 (with a range of 92.15–207.3), whereas 24 h post-initiation, it increased significantly to a median of 159.7 (with a range of 109.6–270.2; P = 0.02). In contrast, no statistically significant differences were observed in PEEP, tidal volume, and invasive MV status before and after NAC initiation. Conclusion: This study concludes that adjunctive NAC therapy in critically ill patients with COVID-19 was associated with improved P/F ratio 24 h:24-h post-initiation. This improvement occurred without significant differences observed in PEEP, tidal volume, and invasive MV status. However, it is essential to conduct randomized control trials to validate these findings and determine their clinical significance.

The Association between Dynamic Pressure Gradient and Mortality in Patients with Acute Respiratory Distress Syndrome in a Pediatric Intensive Care Unit: A Single-Center Retrospective Cohort

Abstract Background: Lung-protective ventilation strategies, one of which is to limit peak inspiratory pressure (PIP), are recommended in the management of acute respiratory distress syndrome (ARDS). The purpose of this study was to determine whether dynamic pressure gradient, defined as the difference between PIP and positive end-expiratory pressure (PEEP), is associated with pediatric ARDS mortality in the pediatric intensive care unit (PICU). Materials and Methods: This was a retrospective, single-center cohort study with consecutive sampling. Children aged 1 month to 18 years with ARDS who were admitted to PICU and used invasive mechanical ventilator between January and December 2023 were included. Patient’s demographic data, pediatric logistic organ dysfunction 2 (PELOD-2) score, oxygenation index (OI), oxygen saturation index (OSI), PEEP, and dynamic pressure gradient were collected from the patient’s medical record. The outcome is mortality, which is measured upon discharge. Results: The subjects’ median age was 6 months, predominantly male (64.06%). The etiology of ARDS was pneumonia (90.63%) and sepsis (9.37%). Bivariate analysis showed that dynamic pressure gradient (OR = 4.77, 95% CI=1.47–15.5, P = 0.003), PEEP (OR = 3.21, 95% CI = 1.07–9.52, P = 0.033), and PELOD-2 score at 24–72 h (OR = 3.68, 95% CI = 1.146–11.83, P = 0.024) had a significant association with mortality of ARDS patients at PICU. The results of multivariate analysis showed that dynamic pressure gradient had a significant relationship with the mortality of ARDS patients at PICU (OR = 5.22, 95% CI = 1.47–18.56, P = 0.015). Conclusion: Dynamic pressure gradient was associated with mortality in pediatric patients with ARDS who were treated in PICU.

Effects of individualised lung-protective ventilation with lung dynamic compliance-guided positive end-expiratory pressure titration on postoperative pulmonary complications of paediatric video-assisted thoracoscopic surgery: protocol for a randomised controlled trial

IntroductionLung-protective ventilation strategies (LPVS) for one-lung ventilation (OLV) in paediatric patients pose greater challenges than in adults. Optimising LPVS for paediatric OLV to mitigate postoperative pulmonary complications (PPCs) has emerged...

Prospective Evaluation of a Modified Apnea Test in Brain Death Candidates that Does Not Require Disconnection from the Ventilator.

The apnea test (AT) is an important component in the determination of brain death/death by neurologic criteria (BD/DNC) and often entails disconnecting the patient from the ventilator followed by tracheal oxygen insufflation to ensure adequate oxygenation. To rate the test as positive, most international guidelines state that a lack of spontaneous breathing must be demonstrated when the arterial partial pressure of carbon dioxide (PaCO2)≥ 60mm Hg. However, the loss of positive end-expiratory pressure that is associated with disconnection from the ventilator may cause rapid desaturation. This, in turn, can lead to cardiopulmonary instability (especially in patients with pulmonary impairment and diseases such as acute respiratory distress syndrome), putting patients at increased risk. Therefore, this prospective study aimed to investigate whether a modified version of the AT (mAT), in which the patient remains connected to the ventilator, is a safer yet still valid alternative. The mAT was performed in all 140 BD/DNC candidates registered between January 2019 and December 2022: after 10min of preoxygenation, (1) positive end-expiratory pressure was increased by 2mbar (1.5mm Hg), (2) ventilation mode was switched to continuous positive airway pressure, and (3) apnea back-up mode was turned off (flow trigger 10 L/min). The mAT was considered positive when spontaneous breathing did not occur upon PaCO2 increase to ≥ 60mm Hg (baseline 35-45mm Hg). Clinical complications during/after mAT were documented. The mAT was possible in 139/140 patients and had a median duration of 15min (interquartile range 13-19min). Severe complications were not evident. In 51 patients, the post-mAT arterial partial pressure of oxygen (PaO2)was lower than the pre-mAT PaO2, whereas it was the same or higher in 88 cases. In patients with pulmonary impairment, apneic oxygenation during the mAT improved PaO2. In 123 cases, there was a transient drop in blood pressure at the end of or after the mAT, whereas in 12 cases, the mean arterial pressure dropped below 60mm Hg. The mAT is a safe and protective means of identifying patients who no longer have an intact central respiratory drive, which is a critical factor in the diagnosis of BD/DNC. Clinical trial registration DRKS, DRKS00017803, retrospectively registered 23.11.2020, https://drks.de/search/de/trial/DRKS00017803.

A Retrospective Comparison of Clinical and Laboratory Aspects of Patients With COVID-19-Related Acute Respiratory Distress Syndrome (ARDS) and Non-COVID-19-Related ARDS.

This study investigated demographic characteristics, hemodynamic values, respiratory datas, laboratory values ​​such as biochemistry and blood gas, and treatment approaches of coronavirus disease 2019 (COVID-19)-related and non-COVID-19-related acute respiratory distress syndrome (ARDS) patients hospitalized in the intensive care unit (ICU). Determining the differences and similarities between COVID-19-related ARDS (CARDS) patients and non-COVID-19-related ARDS (NCARDS) patients will be useful to better understand these two diseases. A total of 32 NCARDS patients who were followed and treated in the ICU for various reasons between January 2015 and December 2020 and 32 CARDS patients who were followed and treated in the ICU for various reasons between March 2020 and December 2020 were examined retrospectively. Age, gender, comorbidities, Glasgow Coma Scale (GCS), Acute Physiology and Chronic Health Evaluation (APACHE) II Score, blood pressure, heart rate, saturation, laboratory results, arterial blood gas (ABG) values, length of stay in the ICU, intubation, the number of days till the patient was extubated, the treatments applied, admission to the service, and mortality were evaluated. In the comparison between the two groups, the demographic data of the patients, the number of days intubated and extubated, APACHE II scores, and ICU length of stay were not statistically different. Values of positive end-expiratory pressure (PEEP), first hospitalization GCS, first hospitalization hemoglobin (Hgb), albumin at first admission, alanine aminotransferase (ALT) at first admission, and steroid use were found to be significantly different in patients with CARDS (p < 0.001). The median of PEEP values (p = 0.04), first admission GCS values (p = 0.04), first admission Hgb values (p = 0.005), albumin values at the first admission (p = 0.03), ALT values (p = 0.03), and the rate of steroid use (p = 0.001) of CARDS patients were significantly higher than those of NCARDS patients. The median of the first hospitalization heart rate values (p = 0.009), first hospitalization saturation values (p = 0.001), and first admission neutrophil values (p = 0.03) in NCARDS patients were significantly higher than that of CARDS patients. There was no significant difference between the two groups in terms of mortality, sedation use, inotropic support, C-reactive protein (CRP), and procalcitonin values. CARDS and NCARDS have clinical and laboratory similarities and differences. Therefore, there should be differences in our follow-up and treatment approach to these two disease groups.

Successful Anesthesia Management in Landau–Kleffner Syndrome Undergoing Laparoscopic Surgery: A Case Report

Abstract Landau–Kleffner syndrome (LKS), also known as acquired epileptic aphasia, is a childhood disease associated with acquired aphasia and epileptiform abnormalities on the electroencephalographic. We report the uneventful anesthesia management of a 17-year-old female patient with LKS syndrome. Her vital signs and laboratory results were normal, and plasma levels of valproic acid (73.6 µg/mL) were within therapeutic limits. She had mild micrognathia, short thyromental distance, and normal neck movements and mouth opening. An intravenous induction was performed with 100 mg lidocaine, 100 µg fentanyl, 200 mg propofol, and 60 mg rocuronium intravenously. After preoxygenation with 80% O2 for 3 min, she was intubated without complications with a number 7.5 mm endotracheal tube connected to a ventilator. Anesthesia maintenance was provided with 2.2% sevoflurane and 50% oxygen–50% air mixture, 0.01–0.05 μg/kg/min infusion of remifentanil. The target partial pressure of carbon dioxide was 30–35 mm Hg. Care was taken to ensure that intra-abdominal pressure did not exceed 14 mm Hg. Spontaneous breathing returned in 5 min after discontinuation of sevoflurane. She was extubated after following commands and transferred to the post-anesthesia care unit. It is unknown whether general anesthesia has a short- or long-term effect on patients with LKS. Since epileptic seizures are essential in patients with LKS, the correct selection of anesthetic agents is significant. In addition, hypoxemia, hypercarbia, hypocapnia, high positive end-expiratory pressure, and acidosis should all be avoided as they may trigger seizure activity.

REDUCING RESPIRATORY VARIATIONS IN INTERNAL JUGULAR VEIN CROSS-SECTIONAL AREA USING PEEP AND TRENDELENBURG POSITION

Introduction: The respiratory cycle influences the size of the right internal jugular vein (RIJV). We evaluated the changes in RIJV size during the respiratory cycle in patients on positive pressure ventilation. Additionally, we investigated the impact of positive end-expiratory pressure (PEEP) and the Trendelenburg position on these respiratory fluctuations. Methods: The study involved 24 patients who underwent general endotracheal anesthesia. Images of the right internal jugular vein (RIJV) were captured in the supine position (baseline, S0) and during three randomized maneuvers: applying a positive end-expiratory pressure (PEEP) of 10 cmH2O (S10), positioning the patient in a 10° Trendelenburg tilt (T0), and combining the Trendelenburg tilt with PEEP (T10). The aim was to measure the cross-sectional area (CSA), anteroposterior diameter, and transverse diameter of the RIJV at both its smallest and largest observed sizes during each maneuver. Results: The study found that all maneuvers significantly reduced the fluctuation in the size of the right internal jugular vein (RIJV) (p = 0.0004). Specifically, compared to the supine position (S0), the maneuvers resulted in the following decreases in the cross-sectional area (CSA) from the smallest to the largest observed sizes: • S0: Decrease by 28.3% • S10: Decrease by 8.5% • T0: Decrease by 8.0% T10: Decrease by 4.4% Additionally, compared to S0, the combination of a 10° Trendelenburg tilt position with a positive end-expiratory pressure (PEEP) of 10 cmH2O significantly increased the CSA: • In the largest observed areas by 83.8% • In the smallest observed areas by 169.4% These findings suggest that the Trendelenburg tilt combined with PEEP was particularly effective in increasing the CSA of the RIJV, both at its largest and smallest observed sizes, compared to other maneuvers and the baseline supine position. Conclusions: A 10° Trendelenburg tilt position combined with a PEEP of 10 cmH2O not only increases the size of the RIJV but also reduces fluctuation by the respiratory cycle.

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.

The Effect of Positive End-Expiratory Pressure on Pulmonary Vascular Resistance Depends on Lung Recruitability in Patients with Acute Respiratory Distress Syndrome.

Rationale: A U-shaped relationship should exist between lung volume and pulmonary vascular resistance (PVR), with minimal PVR at FRC. Thus, positive end-expiratory pressure (PEEP) in patients with acute respiratory distress syndrome (ARDS) should increase PVR if it induces significant lung distension compared with recruitment. However, this has never been proved in patients. Objectives: To study the effects of PEEP on PVR according to lung recruitability, evaluated by the recruitment-to-inflation (R/I) ratio. Methods: In patients with ARDS, we measured hemodynamic (pulmonary artery catheter), echocardiographic, and ventilatory variables (including esophageal pressure) at both low PEEP and higher PEEP by 10 cm H2O. Preload responsiveness was assessed by the passive leg-raising test at high PEEP. Measurements and Main Results: We enrolled 23 patients, including 10 low recruiters (R/I <0.5) and 13 high recruiters (R/I ⩾0.5). Raising PEEP from 4 (2-5) to 14 (12-15) cm H2O increased PVR in low recruiters (from 160 [120-297] to 243 [166-380] dyn·s/cm5; P < 0.01), whereas PVR was unchanged in high recruiters (from 224 [185-289] to 235 [168-300] dyn·s/cm5; P = 0.55). Right-to-left ventricular end-diastolic area ratio simultaneously increased in low recruiters (from 0.54 [0.50-0.59] to 0.64 [0.56-0.70]; P < 0.01) while remaining stable in high recruiters (from 0.70 [0.65-0.79] to 0.68 [0.58-0.80]; P = 0.48). Raising PEEP decreased cardiac index only in preload responsive patients. Conclusions: PEEP increases PVR only when it induces significant lung distension compared with recruitment according to the R/I ratio. Tailoring PEEP on this recruitability index should mitigate its hemodynamic effects.

Pneumomediastinum and pneumothorax in coronavirus disease-2019: Description of a case series and a matched cohort study

ObjectiveTo describe the characteristics of COVID-19 patients with pneumothorax and pneumomediastinum (PTX/PM) and their association with patient outcomes. Patients and methodsAdults admitted to five Mayo Clinic hospitals with COVID-19 between 03/2020–01/2022 were evaluated. PTX/PM was defined by imaging. Descriptive analyses and a matched (age, sex, admission month, COVID-19 severity) cohort comparison was performed. Hospital mortality, length of stay (LOS), and predisposing factors were assessed. ResultsAmong 6663 patients, 197 had PTX/PM (3 %) (75 PM, 40 PTX, 82 both). The median age was 59, with 71 % males. Exposure to invasive and non-invasive mechanical ventilation and high-flow nasal cannula before PTX/PM were 42 %, 17 %, and 20 %, respectively. Among isolated PTX and PM/PTX patients 70 % and 53.7 % underwent an intervention, respectively, while 96 % of the PM-only group was followed conservatively.A total of 171 patients with PTX/PM were compared to 171 matched controls. PTX/PM patients had more underlying lung disease (40.9 vs. 23.4 %, p < 0.001) and lower median body mass index (BMI) (29.5 vs. 31.3 kg/m2, p = .007) than controls. Among patients with available data, PTX/PM patients had higher median positive end-expiratory and plateau pressures than controls; however, differences were not significant (10 vs. 8 cmH2O; p = 0.38 and 28 vs. 22 cmH2O; p = 0.11, respectively). PTX/PM patients had a higher odds of mortality (adjusted odds ratio [95%CI]: 3.37 [1.61–7.07]) and longer mean LOS (percent change [95%CI]: 39 [9–77]) than controls. ConclusionIn COVID-19 patients with similar severity, PTX/PM patients had more underlying lung disease and lower BMI. They had significantly increased mortality and LOS.

Quantitative Comparison of Ventilation Parameters of Different Approaches to Ventilator Splitting and Multiplexing.

Amid the COVID-19 pandemic, this study delves into ventilator shortages, exploring simple split ventilation (SSV), simple differential ventilation (SDV), and differential multiventilation (DMV). The knowledge gap centers on understanding their performance and safety implications. Our hypothesis posits that SSV, SDV, and DMV offer solutions to the ventilator crisis. Rigorous testing was anticipated to unveil advantages and limitations, aiding the development of effective ventilation approaches. Using a specialized test bed, SSV, SDV, and DMV were compared. Simulated lungs in a controlled setting facilitated measurements with sensors. Statistical analysis honed in on parameters like peak inspiratory pressure (PIP) and positive end-expiratory pressure. Setting target PIP at 15 cm H2O for lung 1 and 12.5 cm H2O for lung 2, SSV revealed a PIP of 15.67 ± 0.2 cm H2O for both lungs, with tidal volume (Vt) at 152.9 ± 9 mL. In SDV, lung 1 had a PIP of 25.69 ± 0.2 cm H2O, lung 2 at 24.73 ± 0.2 cm H2O, and Vts of 464.3 ± 0.9 mL and 453.1 ± 10 mL, respectively. DMV trials showed lung 1's PIP at 13.97 ± 0.06 cm H2O, lung 2 at 12.30 ± 0.04 cm H2O, with Vts of 125.8 ± 0.004 mL and 104.4 ± 0.003 mL, respectively. This study enriches understanding of ventilator sharing strategy, emphasizing the need for careful selection. DMV, offering individualization while maintaining circuit continuity, stands out. Findings lay the foundation for robust multiplexing strategies, enhancing ventilator management in crises.

Correlation between normally aerated lung and respiratory system compliance at clinical high positive end-expiratory pressure in patients with COVID-19

Normally aerated lung tissue on computed tomography (CT) is correlated with static respiratory system compliance (Crs) at zero end-expiratory pressure. In clinical practice, however, patients with acute respiratory failure are often managed using elevated PEEP levels. No study has validated the relationship between lung volume and tissue and Crs at the applied positive end-expiratory pressure (PEEP). Therefore, this study aimed to demonstrate the relationship between lung volume and tissue on CT and Crs during the application of PEEP for the clinical management of patients with acute respiratory distress syndrome due to COVID-19. Additionally, as a secondary outcome, the study aimed to evaluate the relationship between CT characteristics and Crs, considering recruitability using the recruitment-to-inflation ratio (R/I ratio). We analyzed the CT and respiratory mechanics data of 30 patients with COVID-19 who were mechanically ventilated. The CT images were acquired during mechanical ventilation at PEEP level of 15 cmH2O and were quantitatively analyzed using Synapse Vincent system version 6.4 (Fujifilm Corporation, Tokyo, Japan). Recruitability was stratified into two groups, high and low recruitability, based on the median R/I ratio of our study population. Thirty patients were included in the analysis with the median R/I ratio of 0.71. A significant correlation was observed between Crs at the applied PEEP (median 15 [interquartile range (IQR) 12.2, 15.8]) and the normally aerated lung volume (r = 0.70 [95% CI 0.46–0.85], P < 0.001) and tissue (r = 0.70 [95% CI 0.46–0.85], P < 0.001). Multivariable linear regression revealed that recruitability (Coefficient = − 390.9 [95% CI − 725.0 to − 56.8], P = 0.024) and Crs (Coefficient = 48.9 [95% CI 32.6–65.2], P < 0.001) were significantly associated with normally aerated lung volume (R-squared: 0.58). In this study, Crs at the applied PEEP was significantly correlated with normally aerated lung volume and tissue on CT. Moreover, recruitability indicated by the R/I ratio and Crs were significantly associated with the normally aerated lung volume. This research underscores the significance of Crs at the applied PEEP as a bedside-measurable parameter and sheds new light on the link between recruitability and normally aerated lung.

Mechanical power during robotic-assisted laparoscopic prostatectomy: an observational study

BackgroundRobotic-assisted laparoscopic radical prostatectomy (RALP) requires pneumoperitoneum and steep Trendelenburg position. Our aim was to investigate the influence of the combination of pneumoperitoneum and Trendelenburg position on mechanical power and its components during RALP.MethodsSixty-one prospectively enrolled patients scheduled for RALP were studied in supine position before surgery, during pneumoperitoneum and Trendelenburg position and in supine position after surgery at constant ventilatory setting. In a subgroup of 17 patients the response to increasing positive end-expiratory pressure (PEEP) from 5 to 10 cmH2O was studied.ResultsThe application of pneumoperitoneum and Trendelenburg position increased the total mechanical power (13.8 [11.6 – 15.5] vs 9.2 [7.5 – 11.7] J/min, p < 0.001) and its elastic and resistive components compared to supine position before surgery. In supine position after surgery the total mechanical power and its elastic component decreased but remained higher compared to supine position before surgery. Increasing PEEP from 5 to 10 cmH2O within each timepoint significantly increased the total mechanical power (supine position before surgery: 9.8 [8.4 – 10.4] vs 12.1 [11.4 – 14.2] J/min, p < 0.001; pneumoperitoneum and Trendelenburg position: 13.8 [12.2 – 14.3] vs 15.5 [15.0 – 16.7] J/min, p < 0.001; supine position after surgery: 10.2 [9.4 – 10.7] vs 12.7 [12.0 – 13.6] J/min, p < 0.001), without affecting respiratory system elastance.ConclusionMechanical power in healthy patients undergoing RALP significantly increased both during the pneumoperitoneum and Trendelenburg position and in supine position after surgery. PEEP always increased mechanical power without ameliorating the respiratory system elastance.

In Vivo Measurement of Tidal Volume During Non-invasive Respiratory Support by Continuous-Flow Helmet CPAP

Recently, the interest in the Helmet interface during non-invasive respiratory support (NIRS) has increased due to the COVID-19 pandemic. During NIRS, positive end-expiratory pressure (PEEP) can be given as continuous positive airway pressure (CPAP), which maintains a positive airway pressure throughout the whole respiratory cycle with Helmet as an interface (H-CPAP). The main disadvantage of the H-CPAP is the inability to measure tidal volume (VT). Opto-electronic plethysmography (OEP) is a non-invasive technique that is not sensitive to gas compression/expansion inside the helmet. OEP acquisitions were performed on 28 healthy volunteers (14 females and 14 males) at baseline and during Helmet CPAP. The effect of posture (semi-recumbent vs. prone), flow (50 vs. 60 L/min), and PEEP (0 vs. 5 vs. 10 cmH2O) on the ventilatory and thoracic-abdominal pattern and the operational volumes were investigated. Prone position limited vital capacity, abdominal expansion and chest wall recruitment. A constant flow of 60 L/min reduced the need for the subject to ventilate while having a slight recruitment effect (100 mL) in the semi-recumbent position. A progressive increasing recruitment was found with higher PEEP but limited by the prone position. It is possible to accurately measure tidal volume during H-CPAP to deliver non-invasive ventilatory support using opto-electronic plethysmography during different clinical settings.

Mean airway pressure - Minute ventilation product (mM): A simple and universal surrogate equation to calculate mechanical power in both volume and pressure controlled ventilation

Introduction Mechanical power represents the energy delivered by a mechanical ventilator onto the lungs. It incorporates all the variables participating in ventilator-induced lung injury, including driving pressure, tidal volume, positive end expiratory pressure, and respiratory rate. The pitfall of mechanical power is its mathematical complexity, as the gold standard method of calculation involves deriving the inspiratory area under the pressure-volume curve of each breath. Prior studies attempted to create simplified equations, they lack clinical utility as calculations cannot be done by solely looking at ventilator settings or they require manipulation of variables. There are also different formulas depending on the type of the mode of ventilation used. This study offers a simplified, universal equation called the mean airway pressure - Minute ventilation product (mM equation) which renders mechanical power clinical application more feasible at the bedside. Methods and Statistics Data collection used the online SIVA simulator, which simulate mechanical ventilation and calculate the geometrical area of the inspiratory limb of the pressure-volume curve. Different combinations of passive scenarios with varying compliances (10-80 ml/cmH2O) and resistances (5-30 cmH2O/L/S) in each the VCV and PCV modes were accomplished by adjusting ventilator settings with respiratory rate (5-40 BPM), tidal volume (150-700 mL), DP (5-30 cmH2O), and PEEP (0-15 cmH2O), with different inspiratory times in PCV and different flows rates in the VCV. A total of 2,000 values were collected in each mode. Range of Mechanical power measured by the simulator: 0.1 - 105 J/min and range of mM equation (mean airway pressure x Minute ventilation): 0.37 - 820 cmH2O/L/min. Pearson correlation coefficients were calculated to compare the relationship of the mM equation to the measured MP, and linear regressions were used for predicting the MP derived from the mM equation in each mode separately and when combining all data from both modes. T-test for equal variance and Bland Altmann plot were used to compare the reference MP measured (MPR) from the simulator to the one derived from the Mm formula (MPD). Results There was a statistically significant linear relationship (P &lt; 0.001) and strong correlation of determination (R2 = 0.931), CI (0.961, 0.967) between the mM formula and the gold-standard method of calculating mechanical power for the combined two modes. For the VCV: there was a statistically significant linear relationship (P &lt; 0.001) and strong correlation of determination (R2 = 0.936), CI (-0.963, 0.971). For the PCV: there was a statistically significant linear relationship (P &lt; 0.001) and strong correlation of determination (R2 = 0.936), CI (-0.964, 0.970). A linear regression model predicted the MP from the mM as follows: for both modes MP = 0.13 (mM) + 3.41, for PCV MP = 0.15 (mM) + 3.79, for VCV MP = 0.13 (mM) + 2.48. The derived mechanical power from the mM was not statistically different (P 0.498) from the calculated reference MP using two sample T-tests assuming equal variance. The Bland-Altman plot for VCV mode showed a mean of 0.78 with 95% CI (0.34, 1.22), SD (-13.27, 14.83). In PCV, a mean of - 0.53 with 95% CI (-0.68, -0.38), SD (-6.28, 5.22). For both modes, a mean of 0, with 95% CI (-0.2, 0.2), SD (-10.06, 10.05). Conclusion The mM equation and its MP derived formula is a reliable method of calculating mechanical power. The simplicity and universal nature of its calculation can provide significant clinical utility at the bedside. More studies are needed to validate this method of calculation. Keywords: Mechanical power, mean airway pressure, minute ventilation

Anesthetic management of broncho- alveolar lavage in pulmonary alveolar proteinosis: A case report

: Pulmonary alveolar proteinosis (PAP) is a very rare, life threatening, noninflammatory, diffuse lung disorder characterized by dense accumulation of lipo-proteinaceous material within the alveoli causing hypoxemia, restrictive lung disease leading to respiratory failure. Whole lung lavage (WLL) is considered as the treatment of choice which includes infusing warm saline in the lungs and draining it out with the lipo-porteinaceous materials thereby clearing the obstruction. WLL requires good team co-ordination between the anaesthesiologists, pulmonologists and physiotherapists. The procedural course is challenging in many aspects like hypoxaemia and hemodynamic fluctuations. Post procedure short term mechanical ventilation is commonly required.: A 45 year old female, diagnosed case of PAP presented with dyspnea at rest with increasing oxygen requirement. After clinical examination and investigations, due to severity of the disease, broncho-alveolar lavage (BAL) of left lung was planned with subsequent right lung BAL after few days. During the procedure, desaturation upto 78% was noted. With meticulous corrective measures, saturation picked up and the procedure was completed uneventfully. Post-operatively patient was mechanically ventilated and extubated after 32 hours.: WLL is the treatment of choice for PAP which involves multidisciplinary approach with mulitple challenges. Pre-oxygenation, adequate lung isolation with left sided double lumen tube (DLT), one lung ventilation with positive end expiratory pressure (PEEP), vigilant intra-operative monitoring, cautious use of positional manoeuvres and recruitment manoeuvres with a good teamwork is the key for successful outcome.