Peak Inspiratory Pressure Research Articles

Incidence of post-intensive care syndrome among patients admitted to post-ICU multidisciplinary consultations: the retrospective observational PICS-MIR study

To determine the prevalence of functional, respiratory and renal impairments and of post-intensive-care-syndrome (PICS) among patients who had attended a post-ICU multidisciplinary consultation (post-ICU-MC) around 3 months after ICU discharge, we performed a retrospective, monocentric observational study, at Clermont Ferrand University hospital, France. We included patients who had attended a post-ICU-MC. Their characteristics during ICU stay and at the post-ICU-MC were collected. Functional status was assessed by the 6-min-walking test, handgrip test and peak inspiratory pressure, respiratory function by exploratory functional outcomes, mental status by SF-36 score, and quality of life by SF-36 score and European Quality of Life 5 Dimensions questionnaire. Overall, we enrolled 67 patients, of whom 70%, 74%, and 68% had functional, respiratory, and renal impairments, respectively, at the post-ICU-MC. Additionally, 40%, 28%, 19%, and 2.5% had three, two, one, and none of these impairments, respectively. All patients experienced mental disorders and a decline in quality of life. Functional impairment correlated with frailty score and sex, and respiratory function with age. To conclude, the prevalence of PICS in our cohort was high, as was that of functional, respiratory and renal failure.

Evaluation of decision support to wean patients from mechanical ventilation in intensive care: a prospective study reporting clinical and physiological outcomes.

This study investigated the clinical and physiological response to use of the BEACON Caresystem, a bedside open-loop decision support system providing advice to guide clinicians when weaning patients from invasive mechanical ventilation. Multicenter prospective study conducted in five adult intensive care units in the UK. Following screening and assent, intubated patients mechanically ventilated for > 24 h were randomized to intervention or usual care. Intervention consisted of application of the BEACON Caresystem's advice on tidal volume/inspiratory pressure, inspired oxygen, respiratory rate and PEEP. Usual care was defined as local clinical practice. The primary outcome was duration of mechanical ventilation. Secondary outcomes quantified prolonged intubation and survival; adverse events; ventilator settings and physiological state; time spent in ventilator modes; links to other therapy; the frequency of advice utilization and time spent outside normal physiological limits. The study was terminated early with a total of 112 patients included. Fifty-four were randomised to the intervention arm and fifty-eight to usual care. The study was underpowered and no significant differences were seen in duration of mechanical ventilation (p = 0.773), prolonged intubation or survival. Intervention arm patients had lower rates of adverse events (p = 0.016), including fewer hypoxaemic events (p = 0.008) and lower values of PEEP (p = 0.030) and tidal volume (p = 0.042). Values of peak inspiratory pressure and pressure support were reduced but at the boarder of statistical significance (p = 0.104, p = 0.093, respectively). No differences were seen for time in ventilator mode or other therapy. Advice presented by the decision support system was applied at the beside an average of 88% of occasions, with a significantly increased number of changes only in inspired oxygen fraction. No significant differences were seen in time spent outside physiological limits. This study investigated the use of the BEACON Caresystem, an open loop clinical decision support system providing advice on ventilator settings. It was terminated early, with no significant difference shown in duration of mechanical ventilation, the primary outcome. Application of advice indicated potential for fewer adverse events and improved physiological status. (Trial registration ClinicalTrials.gov under NCT03249623. Registered 22nd June 2017).

An investigation into the contributing factors to survival of ARDS patients supported by veno-venous ECMO.

This study aimed to identify characteristics associated with survival during and post Extra Corporeal Membrane Oxygenation (ECMO) therapy, in patients with acute respiratory distress syndrome (ARDS) during the COVID-19 pandemic. A retrospective observational study on 94 consecutive patients with confirmed COVID-19 induced ARDS supported by ECMO was carried out 49/94 (52.7%) patients survived to hospital discharge. Non-survivors were found to have significantly (p < .05) higher: Pre-ECMO International normalized ratios (INR), carbon dioxide partial pressure (pCO2), Acute Kidney Injury (AKI) scores and blood urea levels. Also, lower pre-ECMO peak inspiratory pressures (PIP), mean arterial pressure, saturation of arterial oxygen (SaO2), blood bicarbonate levels (HCO3), blood Ph and fewer trials off ECMO with shorter combined trial off times. Patients that did not survive were more likely to have renal impairment and have received peri-ECMO haemofiltration. Poor prognosis was significantly associated with: receiving pre-ECMO nitric oxide (HR = 3.047, CI = 1.247-7.447, p = .015), renal impairment (HR = 3.023, CI = 1.586-5.763, p < .001), AKI of 2 (HR = 3.611, CI = 1.382-9.441, p = .009) or 3 (HR = 3.275, CI = 1.235-8.685, p = .017), peri-ECMO haemofiltration (HR = 2.412, CI = 1.310-4.442, p = .005) and the ABO blood group B (HR = 3.103, CI = 1.335-7.212, p = .008). pre-ECMO high CO2 (HR = 1.134, CI = 1.031-1.248, p = .010), blood lactate (HR = 1.350, CI = 1.156-1.576, p < .001), INR (HR = 2.571, CI = 1.438-4.598, p=<0.001) and lower blood Ph (HR = 0.023, CI = 0.002-0.210, p < .001). Commonly used mortality scores may not be of use in a COVID-19 cohort of ECMO patients. The initiation of ECMO needs to be implemented prior to metabolic derangements, renal and fulminant respiratory failure.

Risk factors affecting the development of pneumothorax in patients followed up in intensive care with a diagnosis of COVID-19

BackgroundPneumothorax is a little known and reported complication of COVID-19. These patients have poorer general outcomes and greater respiratory support requirements, longer hospitalization times, and higher mortality rates. The purpose of this study was to determine which factors predict mortality in patients with tube thoracostomy diagnosed with COVID-19, admitted to the COVID-19 intensive care unit (ICU), and developing pneumothorax.MethodsThis respective, observational study was conducted in all COVID-19 ICUs at the Marmara University Pendik Training and Research Hospital, Türkiye. Patients admitted to the ICU with diagnoses of COVID-19 pneumonia and with chest tubes inserted due to pneumothorax were investigated retrospectively.ResultsOne hundred patients with tube thoracostomy were included in the study. Their median age was 68 (57–78), and 63% were men. The median follow-up time was 20 [10–29] days, and the median time from initial reverse transcriptase polymerase chain reaction (RT-PCR) results to tube thoracostomy was 17 [9–23] days. Initial RT-PCR results were positive in 90% of the patients, while 8% were negative, and 2% were unknown. Half the patients exhibited pulmonary involvement at thoracic computed tomography (CT) (n = 50), while 22 patients had COVID-19 reporting and data system (CO-RADS) scores of 5 (22%). Sixty-two patients underwent right tube thoracostomy, 24 left side placement, and 14 bilateral placement. The patients’ mean positive end expiratory pressure (PEEP) level was 10.31 (4.48) cm H2O, with a mean peak inspiratory pressure (PIP) level of 26.69 (5.95) cm H2O, a mean fraction of inspired oxygen (FiO2) level of 80.06 (21.11) %, a mean respiratory rate of 23.71 (5.62) breaths/min, and a mean high flow nasal cannula (HFNC) flow rate of 70 (8.17) L/min. Eighty-seven patients were intubated (87%), six used non-rebreathable reservoir masks, four HFNC, two non-invasive mechanical ventilation (NIV), and one a simple face mask. Comorbidity was present in 70 patients, 25 had no comorbidity, and the comorbidity status of five was unknown. Comorbidities included hypertension (38%), diabetes mellitus (23%), cardiovascular disease (12%), chronic obstructive pulmonary disease (5%), malignancy (3%), rheumatological diseases (3%), dementia (2%) and other diseases (9%). Twelve of the 100 patients survived. The median survival time was 20 (17.82–22.18) days, and the median 28-day overall survival rate was 29% (20-38%). The multivariate Cox proportional hazards model indicated that age over 68 (HR = 2.23 [95% CI: 1.39–3.56]; p = 0.001), oxygenation status other than by intubation (HR = 2.24 [95% CI: 1.11–4.52]; p = 0.024), and HCO3- below 22 compared with a normal range of 22 to 26 (HR = 1.95 [95% CI: 1.08–3.50]; p = 0.026) were risk factors associated with mortality in patients in the ICU.ConclusionsAge over 68, receipt of oxygenation other than by intubation, and HCO3- values lower than 22 in patients with COVID-19 pneumonia emerged as prognostic factors associated with mortality in terms of pneumothorax.

A novel method for positive airway pressure delivery: pulsating airflow.

The primary objective is to determine if pulsating airflow can achieve therapeutic pharyngeal pressure levels without requiring a tight-sealing mask. A pilot study included 12 nasal-breathing adults who are currently using positive airway pressure (PAP) for therapy. Patients were awake, and pharyngeal pressures were measured using a miniature pressure probe inserted through their nares. Pulsating airflow was applied via a nasal cannula with a customized valve. The inspiratory flow rate was increased until the pharyngeal pressure matched or exceeded the participant's prescribed PAP level. The expiratory flow rate was maintained at a constant low level of continuous airflow. The study demonstrated that pulsating airflow could generate pharyngeal pressures equivalent to or higher than those achieved with PAP therapy in all participants. The peak inspiratory pressures with pulsating airflow followed an oscillatory pattern matching the pulsation frequency. The mean peak pressure increased linearly with the pulsating flow rate. Compared to a high-flow nasal cannula, pulsating airflow produced significantly higher inspiratory pharyngeal pressures, reaching nearly 20 cmH2O. Pulsating airflow could be a viable method for delivering PAP therapy to patients with respiratory or sleep disorders without needing a tight-sealing mask. Further research is required to establish whether this method can improve patient compliance with PAP therapy, assess long-term safety and efficacy, and explore the impact of varying pulsation parameters on treatment outcomes.

Safety of Small-Diameter Endotracheal Tubes in Microlaryngeal Surgery.

Microlaryngeal surgeries require unique considerations for airway management to facilitate patient safety and adequate surgical exposure. Small-diameter endotracheal tubes (ETTs) are widely used but have raised concerns regarding patient safety, including questions about the potential for barotrauma, effective ventilation, and adequate oxygenation. We hypothesize that small ETTs will prove to be safe in a variety of cases. We conducted a case series analyzing the safety of 5.0 ETTs in microlaryngeal surgeries at Washington University School of Medicine from November 2020 to November 2023. Outcome measures included intraoperative desaturations (SpO2 < 90% for >2 min), high peak inspiratory pressures (PIPs) (>40 cm H2O), and prolonged extubation times (>15 min). Univariate regression models were used to analyze associations of sociodemographic and clinical variables with these outcome measures. This study included 76 small-ETT microlaryngeal surgeries. There were 5 instances of desaturations, no reported incidents of barotrauma, and no cases in which intraoperative tube exchange was required due to issues with oxygenation or ventilation. Median PIP was 38 cm H2O, with a range of 17-78 cm H2O. 46% of patients had a PIP above 40 cm H2O. There were prolonged extubation times in 14% of procedures. No association was shown between sociodemographic and clinical variables with risk of desaturations, high PIPs, or prolonged extubation times. Our study suggests that 5.0 ETTs are safe for microlaryngeal surgery in a variety of patients. Otolaryngologists and anesthesiologists should consider this information when choosing between the multiple available options for airway management during microlaryngeal surgery. Level 4 Laryngoscope, 2024.

The Impact of Pneumoperitoneum on Mean Expiratory Flow Rate: Observational Insights from Patients with Healthy Lungs.

Surgical pneumoperitoneum (PP) significantly impacts volume-controlled ventilation, characterized by reduced respiratory compliance, elevated peak inspiratory pressure, and an accelerated expiratory phase due to an earlier onset of the airway pressure gradient. We hypothesized that this would shorten expiratory time, potentially increasing expiratory flow rate compared to pneumoperitoneum conditions. Calculations were performed to establish correlations between respiratory parameters and the mean increase in expiratory flow rate relative to baseline. Mechanical ventilation parameters were recorded for 67 patients both pre- and post-PP. Ventilator settings were standardized with a tidal volume of 6 mL/kg, a respiratory rate of 12 breaths per minute, a PEEP of 3 cmH2O, an inspiratory time of 2 s, and an inspiratory-to-expiratory ratio of 1:1.5 (I:E). The application of PP increased both peak inspiratory pressure and mean expiratory flow rate by 28% compared to baseline levels. The elevated intra-abdominal pressure of 20 cmH2O resulted in a 34% reduction in dynamic chest compliance, a 50% increase in elastance, and a 20% increase in airway resistance. The mean expiratory flow rate increments relative to baseline showed a significant negative correlation with elastance (p = 0.0119) and a positive correlation with dynamic compliance (p = 0.0028) and resistance (p = 0.0240). A PP of 20 cmH2O resulted in an increase in the mean expiratory flow rate in the conventional I:E ratio in the volume-ventilated mode. PP reduces lung and chest wall compliance by elevating the diaphragm, compressing the thoracic cavity, and increasing airway pressures. Consequently, the lungs and chest wall stiffen, requiring greater ventilatory effort and accelerating expiratory flow due to increased airway resistance and altered pulmonary mechanics. Prolonging the inspiratory phase through I:E ratio adjustment helps maintain peak inspiratory pressures closer to baseline levels, and this method enhances the safety and efficacy of mechanical ventilation in maintaining optimal respiratory function during laparoscopic surgery.

Surgical conditions in experimental laparoscopy: effects of pressure, neuromuscular blockade, and pre-stretching on workspace volume.

Establishing a pneumoperitoneum for laparoscopy is common surgical practice, with the goal to create an optimal surgical workspace within the abdominal cavity while minimizing insufflation pressure. Individualized strategies, based on neuromuscular blockade (NMB), pre-stretching routines, and personalized intra-abdominal pressure (IAP) to enhance surgical conditions are strategies to improve surgical workspace. However, the specific impact of each factor remains uncertain. This study explores the effects and side-effects of modifying intra-abdominal volume (IAV) through moderate and complete NMB in a porcine laparoscopy model. Thirty female Landrace pigs were randomly assigned to groups with complete NMB, regular NMB and a control group. Varying IAP levels were applied, and IAV was measured using CT scans. The study evaluated the maximum attainable IAV (Vmax), the pressure at which the cavity opens (p0), and the ease of expansion (λexp). Cardiorespiratory parameters, including peak inspiratory pressure (PIP), mean arterial pressure (MAP), heart rate (HR), and cardiac output (CO), were continuously recorded to evaluate side-effects. There were no significant weight differences between NMB groups (median 21.1kg). Observed volumes ranged from 0 to 4.7 L, with a mean Vmax of 3.82 L, mean p0 of 1.23mmHg, and mean λexp of 0.13hPa-1. NMB depth did not significantly affect these parameters. HR was significantly increased in the complete NMB group, while PIP, MAP, and CO remained unaffected. Repeated insufflation positively impacted Vmax; ease of opening; and expanding the cavity. In this porcine model, the depth of NMB does not alter abdominal mechanics or increase the surgical workspace. Cardiorespiratory changes are more related to insufflation pressure and frequency rather than NMB depth. Future studies should compensate for the positive effect of repeated insufflation on abdominal mechanics and surgical conditions.

Intermittent sigh breaths during high-frequency oscillatory ventilation in preterm infants: a randomised crossover study

ObjectiveTo determine if combining high-frequency oscillatory ventilation (HFOV) with additional sigh breaths would improve end-expiratory lung volume (EELV) and oxygenation in preterm infants.DesignProspective interventional crossover study.SettingNeonatal intensive care unit.PatientsVentilated preterm...

Influence of compliance and resistance of the test lung on the accuracy of the tidal volume delivered by the ventilator

BackgroundLarge variations in respiratory system compliance and resistance may cause the accuracy of tidal volume (VT) delivery beyond the declared range. This study aimed at evaluating the accuracy of VT delivery using a test lung model to simulate pulmonary mechanics under normal or disease conditions.MethodsIn vitro assessment of the VT delivery accuracy was carried out on two commercial ventilators. Measurements of the inspired and expired VT from the ventilator and FlowAnalyser were compared to evaluate the separated and combined influences of compliance and resistance on the delivered VT accuracy. To do this, the errors of five delivered volumes (30 ml, 50 ml, 100 ml, 300 ml, and 500 ml) were checked under 29 test conditions involving a total of 27 combinations of resistance and compliance.ResultsFor the tested ventilator S1 with a flow sensor near the expiratory valve, the average of expired VT errors (ΔVTexp) in three measurements (4 test conditions for each measurement) correlated to test lung compliance (r=-0.96, p = 0.044), and the average of inspired VT errors (ΔVTins) correlated to compliance (r = 0.89, p = 0.106); for the tested ventilator S2 with a flow sensor located at the Y piece, no clear relationship between compliance and ΔVTexp or ΔVTins was found. Furthermore, on two ventilators tested, the current measurements revealed a poor correlation between test lung resistance and ΔVTins or ΔVTexp, and the maximum values of ΔVTexp and ΔVTins correspond to the maximum resistance of 200 cmH2O/(L/s), at which the phenomenon of the flap fluttering in the variable orifice flow senor was observed, and the recorded peak inspiratory pressure (Ppeak) was much higher than the Ppeak estimated by the classical equation of motion. In contrast, at the lower resistance values of 5, 20, 50 and 100 cmH2O/(L/s), the recorded Ppeak was very close to the estimated Ppeak. Overall, the delivered VT errors were in the range of ± 14% on two ventilators studied.ConclusionsDepending on the placement site of the flow sensor in the ventilator circuit, the compliance and resistance of the test lung have different influences on the accuracy of VT delivery, which is further attributed to different fluid dynamics effects of the compliance and resistance. The main influence of compliance is to raise the peak inspiratory pressure Ppeak, thereby increasing the compression volume within the ventilator circuit; whereas a high resistance not only contributes to elevating Ppeak, but more importantly, it governs the gas flow conditions. Ppeak is a critical predictive indicator for the accuracy of the VT delivered by a ventilator.

Recommended recumbency to avoid insertional complications during small-bore wire-guided thoracostomy tube placement in cats—a cadaver study

BackgroundSmall-bore wire-guided thoracostomy tubes (SBWGTT) are commonly used in cats to manage pleural disease and generally have a low complication rate. Our study aimed to explore the correlation between recumbency of cats, placement method, and the occurrence of insertional complications to identify risk factors during SBWGTT placement.In this experimental cadaveric study, SBWGTT placement using a modified Seldinger technique was conducted in 24 feline cadavers. Cats, euthanized for reasons unrelated to the study, were randomly assigned to pleural effusion (EFF; n = 12) and pneumothorax (PNEU; n = 12) groups. Each cadaver was intubated and ventilated with a peak inspiratory pressure (PIP) of 10 mmHg, and sterile saline or air was instilled into the thorax over a 5 mm thoracoscopic trocar in the fourth intercostal space (ICS). Instillation was stopped when the lateral thoracic wall to lung distance (TWLD) reached 10 to 12 mm, measured with ultrasound in the favorable position. Sternal recumbency was the favorable position for the EFF group, and lateral recumbency for the PNEU group. Following the placement of the first SBWGTT in each group, the cadavers were positioned unfavorably (lateral recumbency for EFF group, sternal recumbency for PNEU group), and a second drain was introduced contralaterally. A bilateral 8th ICS thoracotomy was then performed to visually assess intrathoracic structures and drain integrity.A binary logistic regression mixed model was conducted to determine interaction between the induced condition and body position.ResultsA total of 48 SBWGTTs were placed, with complications observed in 33.3% (8/24) of cases. Five of these were major complications consisting of lung lacerations. Complications were more common in the unfavorable position, accounting for 75% of cases, although this result was not statistically significant. The odds of complication rates were > 70% in the unfavorable position and decreased with an increase in TWLD (< 30%).ConclusionComplications associated with SBWGTT placement are influenced by recumbency, although the data did not reach statistical significance. Placing cats in lateral recumbency for pneumothorax treatment and sternal recumbency for pleural effusion treatment may reduce insertional complications.

Evaluation of a new hyperbaric oxygen ventilator during pressure-controlled ventilation.

The stability of a new hyperbaric ventilator (Shangrila590, Beijing Aeonmed Company, Beijing, China) at different clinically relevant pressures in a hyperbaric chamber during pressure-controlled ventilation (PCV) was investigated. The ventilator was connected to a test lung in the multiplace hyperbaric chamber. The inspiratory pressure (PI) of the ventilator was set to 1.0, 1.5, 2.0, 2.5 and 3.0 kPa (approximately 10, 15, 20, 25 and 30 cmH₂O). The compliance and resistance of the test lung were set to 200 mL·kPa⁻¹ and 2 kPa·L⁻¹·s⁻¹, respectively. Experiments were conducted at 101, 203 and 284 kPa ambient pressure (1.0, 2.0 and 2.8 atmospheres absolute respectively). At each of the 5 PI values, the tidal volume (VT), peak inspiratory pressure (Ppeak) and peak inspiratory flow (Fpeak) displayed by the ventilator and the test lung were recorded for 20 cycles. Test lung data were considered the actual ventilation values. The ventilation data were compared among the three groups to evaluate the stability of the ventilator. At every PI, the Ppeak detected by the ventilator decreased slightly with increasing ambient pressure. The Fpeak values measured by the test lung decreased substantially as the ambient pressure increased. Nevertheless, the reduction in VT at 284 kPa and PI 30 cmH₂O (compared to performance at 101 kPa) was comparatively small (approximately 60 ml). In PCV mode this ventilator provided relatively stable VT across clinically relevant PI values to ambient pressures as high as 284 kPa. However, because Fpeak decreases at higher ambient pressure, some user adjustment might be necessary for precise VT maintenance during clinical use at higher PIs and ambient pressures.

Pediatric Resuscitation Skill of Bag-Tube Manual Ventilation: Developing and Using a Mobile Simulation Program to Assess Competency of a Multiprofessional PICU Team.

To assess the skill of bag-tube manual ventilation with the flow-inflating bag in multiprofessional PICU team members using a mobile simulation unit. Prospective observational study from January 2022 to April 2022. In situ mobile simulation using the flow-inflating bag in an academic PICU. Multiprofessional PICU team members including nurses, respiratory therapists, nurse practitioners, fellows, and attendings. None. We enrolled 129 participants who twice completed 1-minute tasks performing bag-tube manual ventilation with a flow-inflating bag. Sessions were video recorded; four could not be analyzed. Only 30% of participants reported being very to extremely confident, and the majority (62%) reported infrequent skill performance. Task success was defined as achieving target pressure ranges during 80% of the delivered breaths, respiratory rate (RR) of 25-35 breaths/min, and successful pop-off valve engagement. Only five of 129 participants (4%) achieved successful ventilation as defined. Overall, participants were more likely to deliver lower pressures and faster rate. Maintaining target positive end-expiratory pressure (PEEP) was least likely to be achieved (19% success), followed by RR (52%), pop-off valve (64%), then peak inspiratory pressure (71%). Nurses were less likely to achieve target pressures compared with all other professions. Multiprofessional PICU team members have highly variable self-confidence with bag-tube manual ventilation using a flow-inflating bag. Observed performance demonstrates rare success with achieving targeted ventilation parameters, in particular maintenance of PEEP. Future research should focus on developing mobile simulation units to facilitate profession-specific, real-time coaching to teach high-quality manual ventilation that can be translated to the bedside.

Effects of Dexmedetomidine in Improving Oxygenation and Reducing Pulmonary Shunt in High-Risk Pediatric Patients Undergoing One-Lung Ventilation for Thoracic Surgery: A Double-Blind Randomized Controlled Trial.

Background and objectives Pediatric thoracic surgery has unique considerations due to the immaturity of the respiratory system anatomically and physiologically, which presents technical and pharmacological considerations, including the very common technique of one-lung ventilation (OLV), which causes serious complications in children. Therefore, we investigated the effects of dexmedetomidine on oxygenation and pulmonary shunt fraction (Qs/Qt) in high-risk pediatric patients undergoing OLV for thoracic surgery. This randomized controlled trial aimed to investigate dexmedetomidine's effect on the partial pressure of arterial oxygen (PaO2) and pulmonary shunt fraction (Qs/Qt). Methods A total of 63 children underwent thoracic surgery with OLV and were divided into two groups. The dexmedetomidine group (group Dex, n = 32) received dexmedetomidine (0.4 μg/kg/hour), and the placebo group (group placebo, n = 31) received normal saline. Two arterial and central venous blood samples were taken for arterial and venous blood gas analysis at four time points: T1 (10 minutes after mechanical ventilation of total lung ventilation), T2 (10 minutes after OLV), T3 (60 minutes after OLV), and T4 (20 minutes after the end of OLV). At these intervals, the following parameters were measured: PaO2, Qs/Qt, mean arterial pressure (MAP), heart rate (HR), and peak inspiratory pressure (PIP). Results The two groups had no significant differences in FEV1/FVC and baseline pulmonary shunt fraction (Qs/Qt). Dexmedetomidine significantly improved PaO2 compared with placebo during OLV (T2 and T3). There was a significant decrease in Qs/Qt compared with placebo during OLV (T2, T3, and T4). There was a decrease in PIP compared with placebo during OLV (T2 and T3). No statistically significant differences in MAP or HR were observed between the groups. Conclusion Infusion of dexmedetomidine during OLV in high-risk pediatric thoracic surgery reduces shunt and pulmonary shunt fraction Qs/Qt, improves PaO2 and body oxygenation, reduces PIP and pressure load, and maintains hemodynamic stability (MAP, HR).

Nebulized Budesonide Prevents Airway Inflammation in Children with High Total IgE Levels After Open Heart Surgery with Cardiopulmonary Bypass: A Prospective Randomized Controlled Trial.

Cardiopulmonary bypass (CPB) is a crucial technique used to repair congenital heart defects (CHD); however, it may induce inflammatory response, leading to airway inflammation and need for prolonged mechanical ventilation. In this study, we aimed to evaluate the effect of budesonide nebulization in children with high serum total immunoglobulin E (tIgE) levels undergoing surgical repair of CHD via CPB. We conducted a randomized, single-center, controlled trial at a tertiary teaching hospital. One-hundred and one children with high tIgE were enrolled and randomized into the budesonide nebulization group (BUD group, n = 50) or the normal saline nebulization group (NS group, n = 51) between January 2020 and December 2020. Budesonide or normal saline was administered through a vibrating mesh nebulizer during mechanical ventilation every 8h. Blood and bronchoalveolar lavage fluid (BALF) samples were examined and data on airway mechanics and clinical outcomes were recorded. IL-6 and IL-8 levels in the blood and BALF samples significantly increased after CPB in both groups. Budesonide inhalation reduced IL-6 and IL-8 levels in the blood and BALF samples in children with high tIgE (P < 0.05). The mean airway pressure, PCO2, and oxygen index in the BUD group were significantly lower than those in the NS group after the first inhalation dose and persisted until almost 24h after surgery. The peak inspiratory pressure and drive pressure were lower in the BUD group than in the NS group at nearly 24h after surgery, with no significant difference at other time points. Additionally, the duration of mechanical ventilation, number of noninvasive ventilations after extubation, and number of patients using aerosol-inhaled bronchodilators after CICU in the BUD group were significantly lower than those in the NS group (P < 0.05). Children with high preoperative tIgE levels are at risk of airway inflammation after cardiopulmonary bypass. Inhaling budesonide during postoperative mechanical ventilation can reduce the intensity of inflammatory reactions, shorten the duration of mechanical ventilation, reduce airway pressure and the utilization of NIV after extubation.

Prognostic value of the oxygenation index measured during mechanical ventilation and weaning. A retrospective cohort study.

The aim of this study was to investigate the predictive value of the ratio of oxygen saturation (ROX) index calculated during mechanical ventilation (MV) and the weaning period in evaluating readiness to weaning and the success of the spontaneous breathing trial (SBT), extubation, and mortality. We also compared the results of the ROX index calculated with partial arterial oxygen pressure (PaO2), arterial oxygen saturation (SaO2%), and probe oxygen saturation (SpO2%). In this retrospective cohort study, the ROX index was calculated by SpO2%, PaO2, and SaO2% separately using the ROX index formula (PaO2 or SaO2 or SpO2 /FiO2)/respiratory rate. ROX was calculated during the first three days of MV treatment and the weaning period daily (SBT). Positive end-expiratory pressure and peak inspiratory pressure values were also recorded during these measurements. These ROX values were used to analyze whether they predict weaning readiness, SBT, extubation failure (EF), and mortality. The study included 107 mechanically ventilated patients. Weaning could be tried in 64 (60%) of the 107 patients; 44 (69%) of the 64 patients succeeded, and extubation was performed. 19 (43%) of 44 patients had EF. ROX values calculated with PaO2 during MV and SBT predicted readiness to wean, EF, and mortality better than ROX values calculated with SaO2 and SpO2. ROX values calculated with PaO2 during the third day of MV had the highest sensitivity and specificity for EF (sensitivity: 81%, specificity: 70% for the ROX<11 value). The results of this study suggest that the calculation of ROX index, not only with SpO2% but also with arterial blood gas PaO2 and SaO2% values, may be helpful in predicting the weaning readiness evaluation, SBT, and extubation success and mortality. Further studies with more patients are necessary to verify and standardize these results.

What is the functional impact of sarcopenia and myosteatosis three months after discharge to an intensive care population? A monocentric observational study

Background & AimsSarcopenia and myosteatosis are proving to be major factors to predict mortality in intensive care patients. Few studies are currently focusing on evaluating the functional impact after intensive care discharge and none has considered sarcopenia and myosteatosis as prognostic factors.The aim of our study was to determine whether sarcopenia and myosteatosis are reliable prognostic factors for mid-term functional impact in critical patients a few months after intensive care discharge. MethodsWe carried out a retrospective monocentric study using computed-tomography scanner performed on intensive care admission and/or three months after discharge to assess sarcopenia and myosteatosis in 43 patients with critical illnesses who underwent a multidisciplinary evaluation on a multidisciplinary consultation’s day hospital.We used L3 and/or T4 computed-tomography-scan levels to assess sarcopenia with the skeletal muscle index and myosteatosis with skeletal muscle density. These data were compared with main patient characteristics on intensive care admission and during intensive care stay and with functional assessments at the post intensive care multidisciplinary consultations, based on hand grip strength test, 6-minute walking test, and peak inspiratory pressure. ResultsWe found a good correlation of both skeletal muscle index and skeletal muscle density for T4 and L3 levels. Skeletal muscle index was correlated with hand grip strength test, and skeletal muscle density with 6-minute walking test, which are both functional tests recommended in the algorithm of the European Working Group on Sarcopenia in Older People to diagnose sarcopenia. Peak inspiratory pressure was correlated with both skeletal muscle index and skeletal muscle density and also with other functional tests. ConclusionsWe confirmed the reliability of thoracic computed-tomography-scan to assess sarcopenia and myosteatosis. We found that skeletal muscle index and skeletal muscle density are independent but complementary predictive factors for functional impact at mid-term in intensive care patients. Peak inspiratory pressure could be a useful tool for the assessment and management of sarcopenia.

Breath-by-breath assessment of acute pulmonary edema using electrical impedance tomography, spirometry and volumetric capnography in a sheep (Ovis Aries) model.

The bedside diagnosis of acute pulmonary edema is challenging. This study evaluated the breath-by-breath information from electrical impedance tomography (EIT), respiratory mechanics and volumetric capnography (VCap) to assess acute pulmonary edema induced by xylazine administration in anesthetized sheep. To determine the ability and efficiency of each monitoring modality in detecting changes in lung function associated with onset of pulmonary edema. Twenty healthy ewes were anesthetized, positioned in sternal (prone) recumbency and instrumented. Synchronized recordings of EIT, spirometry and VCap were performed for 60 s prior to start of injection, during xylazine injection over 60 s (0-60 s) and continuously for 1 min (60-120 s) after the end of injection. After visual assessment of the recorded mean variables, statistical analysis was performed using a mixed effect model for repeated measures with Bonferroni's correction for multiple comparisons, to determine at which breath after start of injection the variable was significantly different from baseline. A significant change over time was defined as an adjusted p < 0.05. All statistics were performed using GraphPad Prism 0.1.0. Electrical impedance tomography showed significant changes from baseline in all but two variables. These changes were observed simultaneously during xylazine injection at 48 s and were consistent with development of edema in dependent lung (decreased end-expiratory lung impedance, ventilation in centro-ventral and ventral lung region) and shift of ventilation into non-dependent lung (decreased non-dependent silent spaces and increased center of ventilation ventral to dorsal and increased ventilation in centro-dorsal and dorsal lung region). All changes in lung mechanics also occurred during injection, including decreased dynamic respiratory system compliance and increased peak expiratory flow, peak inspiratory pressure and airway resistance at 48, 54 and 60 s, respectively. Changes in VCap variables were delayed with all occurring after completion of the injection. In this model of pulmonary edema, EIT detected significant and rapid change in all assessed variables of lung function with changes in regional ventilation indicative of pulmonary edema. Volumetric capnography complemented the EIT findings, while respiratory mechanics were not specific to lung edema. Thus, EIT offers the most comprehensive method for pulmonary edema evaluation, including the assessment of ventilation distribution, thereby enhancing diagnostic capabilities.

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.

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.