High Peak Inspiratory Pressure Research Articles

Echocardiographic assessment of right ventricular performance in COVID-19 related acute respiratory distress syndrome: the importance of systo-diastolic interaction.

The cardiac manifestations of COVID-19 have been described in patients with acute respiratory distress syndrome (ARDS) admitted to intensive care unit (ICU). The presence and impact of right ventricular (RV) diastolic function and performance has not been studied in this population yet. We describe the prevalence of RV diastolic dysfunction, assessed by the pulmonary valve pre-ejection A wave (PV A wave), and the RV systo-diastolic interaction, using the RV total isovolumic time (t-IVT), in COVID-19 ARDS. Prospective observational study enrolling patients with moderate to severe COVID-19 ARDS admitted to ICU who underwent a transthoracic echocardiogram within 24h of ICU admission and at least a second one during the ICU stay. Respiratory, hemodynamic and biochemistry parameters were collected. 163 patients (age 61.0 ± 9.3years, 72% males) were enrolled. 36 patients (22.1%) had RV dysfunction, 45 (27.1%) LV systolic dysfunction. 73 patients (44.7%) had PV A wave. The RV t-IVT correlated with TAPSE at ICU admission (p < 0.002; r -0.61), presence of PV A wave (p < 0.001; r 0.78), peak inspiratory pressure (PIP) (p < 0.001; r 0.42), PEEP (p < 0.001; r 0.68), dynamic driving pressure (DDP) (p < 0.001; r 0.58), and PaO2/FiO2 ratio (p < 0.01; r -0.35). The presence of PV A wave was associated with higher PIP (p < 0.001; r 0.45), higher PEEP (p < 0.001; r 0.56), higher DDP (p < 0.01, r 0.51), and lower PaO2/FiO2 ratio (p < 0.001; r -0.49). RV t-IVT and the presence of PV A wave are non-invasive means to describe a significant RV diastolic dysfunction and may be consider descriptive signs of RV performance in COVID-19 ARDS.

Perioperative Characteristics and Outcomes of Fontan Versus Non-Fontan Patients Undergoing Combined Heart-Liver Transplantation: A Retrospective Cohort Study

Combined heart-liver transplantation (CHLT) is becoming increasingly frequent as a maturing population of patients with Fontan-palliated congenital heart disease develop advanced liver fibrosis or cirrhosis. The authors present their experience with CHLT for congenital and noncongenital indications, and identify characteristics associated with poor outcomes that may guide intervention in high-risk patients. This was a single-center retrospective cohort study. This study was conducted at Vanderbilt University Medical Center in Nashville, Tennessee. The study included 16 consecutive adult recipients of CHLT at the authors' institution between April 2017 and February 2022. Eleven patients underwent transplantation for Fontan indications, and 5 were transplanted for non-Fontan indications. Compared with non-Fontan patients, Fontan recipients had longer cardiopulmonary bypass duration (199 v 119 minutes, p =m0.002), operative times (786 v 599 minutes, p = 0.01), and larger blood product transfusions (15.4 v 6.3 L, p = 0.18). Six of 16 patients required extracorporeal membrane oxygenation (ECMO), of whom 4 were Fontan patients who subsequently died. Patients who required ECMO had lower 5-hour lactate clearance (0.0 v 3.5 mmol/L, p = 0.001), higher number of vasoactive infusions, lower pulmonary artery pulsatility indices (0.58 v 1.77, p = 0.03), and higher peak inspiratory pressures (28.0 v 18.5 mmHg, p = 0.01) after liver reperfusion. Combined heart-liver transplantation in patients with Fontan-associated end-organ disease is particularly challenging and associated with higher recipient morbidity compared with non-Fontan-related CHLT. Early hemodynamic intervention for signs of ventricular dysfunction may improve outcomes in this growing high-risk population.

Continuous chest compressions are associated with higher peak inspiratory pressures when compared to 30:2 in an experimental cardiac arrest model

BackgroundVentilation during cardiopulmonary resuscitation (CPR) has long been a part of the standard treatment during cardiac arrests. Ventilation is usually given either during continuous chest compressions (CCC) or during a short pause after every 30 chest compressions (30:2). There is limited knowledge of how ventilation is delivered if it effects the hemodynamics and if it plays a role in the occurrence of lung injuries. The aim of this study was to compare ventilation parameters, hemodynamics, blood gases and lung injuries during experimental CPR given with CCC and 30:2 in a porcine model.MethodsSixteen pigs weighing approximately 33 kg were randomized to either receive CPR with CCC or 30:2. Ventricular fibrillation was induced by passing an electrical current through the heart. CPR was started after 3 min and given for 20 min. Chest compressions were provided mechanically with a chest compression device and ventilations were delivered manually with a self-inflating bag and 12 l/min of oxygen. During the experiment, ventilation parameters and hemodynamics were sampled continuously, and arterial blood gases were taken every five minutes. After euthanasia and cessation of CPR, the lungs and heart were removed in block and visually examined followed by sampling of lung tissue which were examined using microscopy.ResultsIn the CCC group and the 30:2 group, peak inspiratory pressure (PIP) was 58.6 and 35.1 cmH2O (p < 0.001), minute volume (MV) 2189.6 and 1267.1 ml (p < 0.001), peak expired carbon dioxide (PECO2) 28.6 and 39.4 mmHg (p = 0.020), partial pressure of carbon dioxide (PaCO2) 50.2 and 61.1 mmHg (p = 0.013) and pH 7.3 and 7.2 (p = 0.029), respectively. Central venous pressure (CVP) decreased more over time in the 30:2 group (p = 0.023). All lungs were injured, but there were no differences between the groups.ConclusionsVentilation during CCC resulted in a higher PIP, MV and pH and lower PECO2 and PaCO2, showing that ventilation mode during CPR can affect ventilation parameters and blood gases.

Efficacy of an Automated Secretion Removal Technology at Different Inspiratory Pressures.

Endotracheal suctioning is resource demanding, causes patient discomfort, and is associated with adverse effects. A new artificial cough method has been developed for automated secretion removal by using rapid deflation and inflation of the endotracheal tube cuff during the inspiratory phase of mechanical ventilation. This method has been evaluated in a bench model and in animals but not in human subjects. The aim of this study was to investigate whether this method can remove the need for endotracheal suctioning in subjects and whether this is dependent on ventilator settings. This prospective, non-controlled study recruited 20 subjects on invasive mechanical ventilation. On the clinical need for endotracheal suctioning, the automatic cough procedure was applied 3 times over 30 s, with this repeated at higher ventilatory pressure and lower respiratory frequency if considered unsuccessful. Success was determined by removal of the clinical need for suctioning. Subject safety and comfort was measured by using the Critical-Care Pain Observation Tool before and after the procedure, and negative effects were recorded. To assess intra-subject variability, the procedure was performed on 3 different occasions for each subject. The procedure was successful in 18 of 20 subjects (90%), with mean subject success rates of 53% at low settings (peak inspiratory pressure 21.8 ± 3.8 cm H2O) and 83% at high settings (peak inspiratory pressure 25.6 ± 3.6 cm H2O). The Critical-Care Pain Observation Tool category remained unchanged in 30 procedures (77%), improved in 7 (18%), and deteriorated in 2 (5%). This study illustrated the potential for significant reduction in the clinical need for endotracheal suctioning after the use of an automated artificial cough procedure at both low and high peak inspiratory pressures, and that was well tolerated.

Stratifying Severity of Acute Respiratory Failure Severity in Cyanotic Congenital Heart Disease.

Hypoxemia is used to stratify severity in acute respiratory failure (ARF) but is less useful in cyanotic congenital heart disease (CCHD) due to an inability to differentiate hypoxemia from lung injury versus cardiac shunting. Therefore, we aimed to determine whether variables related to respiratory mechanics were associated with outcomes to assist in stratifying ARF severity in pediatric CCHD. We performed a retrospective cohort study from a single cardiac intensive care unit enrolling children with CCHD with ARF requiring mechanical ventilation between 2011 and 2019. Time-averaged ventilator settings and oxygenation data in the first 24h of ARF were screened for association with the primary outcome of 28-day mortality. Of 344 eligible patients, peak inspiratory pressure (PIP) and driving pressure (ΔP) were selected as candidate variables to stratify ARF severity. PIP (OR 1.10, 95% CI 1.02-1.19) and ΔP (1.11, 95% CI 1.01-1.24) were associated with higher mortality and fewer ventilator-free days (VFDs) at 28days after adjusting for age, severity of cardiac history, and FiO2. A three-level (mild, moderate, severe) severity stratification was established for both PIP (≤ 20, 21-29, ≥ 30) andΔP (≤ 16, 17-24, ≥ 25), showing increasing mortality (both P < 0.01), decreasing VFDs and increasing ventilator days in survivors (all P < 0.05) across increasing pressures. Overall, we found that higher PIP and ΔP were associated with mortality and duration of ventilation across a three-level severity stratification system in pediatric CCHD with ARF, providing a practical method to prognosticate in subjects with multifactorial etiologies for hypoxemia.

High peak inspiratory pressure may be associated with intraoperative coughing during neurosurgery under general anesthesia without neuromuscular blockade: a retrospective study

BackgroundThe endotracheal cuff pressure depends on the airway pressure during positive-pressure ventilation. A high endotracheal cuff pressure may be related to intraoperative coughing, which can be detrimental during neurosurgery. We investigated the incidence of intraoperative coughing and its association with peak inspiratory pressure (PIP) during neurosurgery under general anesthesia without neuromuscular blockade.MethodsThis retrospective study divided 1656 neurosurgical patients who underwent total intravenous anesthesia without additional neuromuscular blockade after tracheal intubation into high (PIP > 21.6 cmH2O, n = 318) and low (PIP ≤ 21.6 cmH2O, n = 1338) PIP groups. After propensity score matching, 206 patients were selected in each group. Demographic, preoperative, surgical, and anesthetic data were collected retrospectively from electronic medical records and continuous ventilator, infusion pump, and bispectral index data from a data registry.ResultsIntraoperative coughing occurred in 30 (1.8%) patients, including 9 (0.5%) during the main surgical procedure. Intraoperative coughing was more frequent in the high PIP group than in the low PIP group before (14/318 [4.4%] vs. 16/1338 [1.2%], P < 0.001) and after (13/206 [6.3%] vs. 1/206 [0.5%], P = 0.003) propensity score matching. In multivariable logistic regression analysis after propensity score matching, a high PIP (odds ratio [95% confidence interval] 14.22 [1.81-111.73], P = 0.012), tidal volume divided by predicted body weight (mL/kg, 1.36 [1.09–1.69], P = 0.006), and surgical duration (min, 1.01 [1.00–1.01], P = 0.025) predicted intraoperative coughing.ConclusionThe incidence of intraoperative coughing was 1.8% in neurosurgical patients undergoing general anesthesia without neuromuscular blockade and might be associated with a high PIP.

Chronic lung disease in Saudi preterm infants

Background: Despite advances in neonatal medicine, chronic lung disease (CLD) remains a major cause of pulmonary morbidity in preterm infants. Objective: To determine the prevalence of CLD and to identify the possible risk factors that may predict the development of CLD. Patients and Methods: A retrospective study of preterm infants admitted to the NICU between July 2011 and June 2022 with gestational age (GA) < 32 weeks and birth weight (BW) < 1500 g was performed. Results: A total of 706 preterm infants were included in the study, of whom 202 (28.6%) infants developed CLD. Of the 202 preterm infants who developed CLD, 194 survivors; 93 (47.9%) had mild, 58 (29.9%) had moderate and 43 (22.2%) had severe CLD. Multivariate analysis showed that low GA (odds ratio [OR]: 0.62; 95% confidence interval [CI]: 0.43-0.98), low BW (OR: 20.6; 95% CI: 17.1-29.3), use of mechanical ventilation (OR: 1.07; 95% CI: 0.87-1.54), higher peak inspiratory pressure (PIP) (OR: 1.48; 95% CI: 1.44-1.91), higher fraction of inspired oxygen (FiO2) use (OR: 0.11; 95% CI: 0.05-0.19), duration of mechanical ventilation (OR: 3.56; 95% CI: 4.28-3.75) and frequent blood transfusion (OR: 0.65; 95% CI: 0.53-0.87) were identified as the main risk factors for the development of CLD. Conclusions: The prevalence of CLD among preterm infants was 28.6%. The most relevant predictors of CLD were GA, BW, mechanical ventilation, higher PIP, higher FiO2 use, duration of mechanical ventilation and frequent blood transfusion.

Factors associated with mortality in acute respiratory failure patients without acute respiratory distress syndrome.

Excess tidal volume and driving pressure were associated with increased mortality in patients with acute respiratory distress syndrome (ARDS). Still, the appropriate mechanical ventilation strategy for patients who do not have ARDS needs to be understood. This study aimed to identify risk factors for mortality in acute respiratory failure patients without ARDS. We included all mechanically ventilated patients who did not meet the criteria for ARDS and were admitted to the medical intensive care unit (ICU) from October 2017 to September 2018. Patients who had tracheostomy before admission, were intubated for more than 24 hours before transfer to ICU, or underwent extracorporeal membrane oxygenation within 24 hours of ICU admission were excluded. Clinical and physiologic data were recorded and compared between survived and non-survived patients. Of 289 patients with acute respiratory failure, 134 patients without ARDS were included; 69 (51%) died within 28 days. Demographics, principal diagnosis, and lung injury score on the first day of admission were not significantly different between survived and non-survived patients. In multivariate analysis, higher peak inspiratory pressure (PIP) during the first 3 days of admission [odds ratio (OR) 1.11, 95% confidence interval (CI): 1.01-1.22, P=0.04], higher sequential organ failure assessment score (OR 1.15, 95% CI: 1.04-1.28, P=0.008) and underlying cerebrovascular diseases (OR 7.09, 95% CI: 1.78-28.28, P=0.006) were independently associated with mortality in these patients, whereas dynamic lung compliance (Cdyn) and respiratory rate were not associated with mortality in the multivariate model. Mortality was high in mechanically ventilated patients without ARDS. Higher PIP is a potentially modifiable risk factor for mortality in these patients, independent of the baseline Cdyn. Underlying cerebrovascular diseases and increased disease severity are also independent factors associated with 28-day mortality.

Perioperative Respiratory-Adverse Events Following General Anesthesia Among Pediatric Patients After COVID-19.

The perianesthetic morbidity, mortality risk and anesthesia-associated risk after preoperative coronavirus disease 2019 (COVID-19) omicron variant in pediatric patients have not been fully demonstrated. We examined the association between preoperative COVID-19 omicron diagnosis and the incidence of overall perioperative adverse events in pediatric patients who received general anesthesia. This retrospective study included patients aged < 18 years who received general anesthesia between February 1 and June 10, 2022, in a single tertiary pediatric hospital. They were divided into two groups; patients in a COVID-19 group were matched to patients in a non-COVID-19 group during the omicron-predominant period in Korea. Data on patient characteristics, anesthesia records, post-anesthesia records, COVID-19-related history, symptoms, and mortality were collected. The primary outcomes were the overall perioperative adverse events, including perioperative respiratory adverse events (PRAEs), escalation of care, and mortality. In total, 992 patients were included in the data analysis (n = 496, COVID-19; n = 496, non-COVID-19) after matching. The overall incidence of perioperative adverse events was significantly higher in the COVID-19 group than in the non-COVID-19 group (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.89-1.94). The difference was significant for PRAEs (OR, 2.00; 95% CI, 1.96-2.02) but not in escalation of care or mortality. The most pronounced difference between the two groups was observed in instances of high peak inspiratory pressure ≥ 25 cmH2O during the intraoperative period (OR, 11.0; 95% CI, 10.5-11.4). Compared with the non-COVID-19 group, the risk of overall perioperative adverse events was higher in the COVID-19 group diagnosed 0-2 weeks before anesthesia (OR, 6.5; 95% CI, 2.1-20.4) or symptomatic on the anesthesia day (OR, 6.4; 95% CI, 3.30-12.4). Pediatric patients with the preoperative COVID-19 omicron variant had increased risk of PRAEs. Patients within 2 weeks after COVID-19 or those with symptoms had a higher risk of PRAEs.

Risk factors for air leakage during invasive mechanical ventilation in pediatric intensive care units

PurposeThis study aimed to investigate air leakage during invasive mechanical ventilation (IMV) in a pediatric intensive care unit (PICU) and explore potential risk factors.MethodsWe conducted a retrospective cohort study of children who underwent IMV in a single-center PICU in a tertiary referral hospital. Air leakage risk factors and factors associated with an improved outcome were assessed.ResultsA total of 548 children who underwent IMV were enrolled in this study. Air leakage occurred in 7.5% (41/548) of the cases in the PICU. Air leakage increased the duration of IMV and hospitalization time. Multivariate logistic regression analysis showed a higher risk of air leakage during IMV for PICU patients with acute respiratory dyspnea syndrome (ARDS) (OR = 4.38), a higher pediatric critical illness score (PCIS) (OR = 1.08), or a higher peak inspiratory pressure (PIP) (OR = 1.08), whereas the risk was lower for patients with central respiratory failure (OR = 0.14). The logistic model had excellent predictive power for air leakage, with an area under the curve of 0.883 and tenfold cross-validation. Patients aged between 1 and 6 years who were diagnosed with measles or pneumonia and had a low positive end-expiratory pressure (PEEP) or high PaO2/FiO2 ratio were associated with improved outcomes. Patients diagnosed with central respiratory failure or congenital heart diseases were associated with less desirable outcomes.ConclusionsPatients with ARDS, a higher PCIS at admission or a higher PIP were at higher risk of air leakage.

Early withdrawal of life sustaining therapy in extracorporeal cardiopulmonary resuscitation (ECPR): Results from the Extracorporeal Life Support Organization registry

AimsAlthough extracorporeal cardiopulmonary resuscitation (ECPR) improves survival outcomes in refractory cardiac arrest, morbidity and mortality remain significantly high. Information on causes of death in ECPR is limited; however, some evidence suggests withdrawal of life sustaining therapy (WLST) is a major factor in ECPR-associated mortality. We sought to describe the patients experiencing WLST after ECPR. MethodsThe international Extracorporeal Life Support Organization (ELSO) Registry was retrospectively queried for patients more than 18 years old supported with ECPR who underwent WLST due to family request from 2007 to 2017. These patients were split into groups for descriptive and multivariable analysis: early (WLST < 72 hours from cannulation) and routine WLST. ResultsOverall, 411 ECPR patients experienced WLST (median age 42 years IQR = 28–51; 31.7% female) over the 10-year period. 55.5% (n = 228) underwent early WLST with a median ECPR duration of 24 hours (IQR = 7–48) versus routine WLST (median = 147 hours; IQR = 105–238). In multivariable regression analysis, lower arterial blood gas pH (aOR = −3.1; 95% CI = 2.18–2.8; p = 0.04), arterial oxygen saturation (aOR = 1.12; 95% CI = 1.01–1.23; p = 0.02), and higher peak inspiratory pressure (aOR = 0.84; 95% CI = 0.71–1.00; p = 0.05) were independently associated with early WLST. Early WLST patients experienced higher rates of all ECMO-related complications except for infections. ConclusionsMore than half of ECPR patients experienced early WLST within 72 hours. The patients with early WLST had worse markers of severe critical illness at 24 hours and experienced higher rates of complications. Further research should include an appropriate control group to better adjust confounders for ECPR-associated death and focus on prognostication.

Characterization of Platelet Biologic Markers in the Early Pathogenesis of Postoperative Acute Respiratory Distress Syndrome.

The objective of this study was to characterize the role of platelets in a postoperative ARDS model through an analysis of two platelet-specific biologic markers: thromboxane A2 (TxA2) and soluble CD-40-ligand (sCD40L). This was a nested case-control study of ARDS cases matched to non-ARDS controls. Blood samples were collected from a cohort of 500 patients undergoing thoracic, aortic vascular, or cardiac surgery that placed them at high-risk of developing postoperative ARDS. TxA2 and sCD40L were analyzed at baseline (prior to surgical incision) as well as 2 hours and 6 hours after the key intraoperative events believed to be associated with increased risk of postoperative ARDS. Of 500 patients enrolled, 20 ARDS cases were matched 1:2 to non-ARDS controls based on age, sex, surgical procedure, and surgical lung injury prediction score. Those who developed ARDS had longer surgeries, greater fluid administration, and higher peak inspiratory pressures. There were no significant differences in levels of TxA2 or sCD40L at baseline, at 2 hours, or at 6 hours. There was also no difference in the change in biomarker concentration between baseline and 2 hours or baseline and 6 hours. Two novel platelet-associated biologic markers (TxA2 and sCD40L) were not elevated in patients who developed ARDS in a postoperative ARDS model. Although limited by the relatively small study size, these results do not support a clear role for platelets in the early pathogenesis of postoperative ARDS.

Lung Thermography as an Early Predictor of Pulmonary Function in Cellular Ex Vivo Lung Perfusion

<h3>Purpose</h3> Infrared thermography is a real-time and non-invasive technique for detecting low temperatures in poorly perfused areas. We hypothesized that the temperature of injured lungs may not increase as rapidly as that of non-injured lungs during the initial 1 h rewarming phase in ex vivo lung perfusion (EVLP). In this study, we investigated the effect of graft thermal changes during the rewarming phase on pulmonary function in cellular EVLP using a porcine lung model. <h3>Methods</h3> Fifteen pigs were divided into three groups: control group (no warm ischemia) or donation after circulatory death groups with 60 or 90 min of warm ischemia (n = 5, each). Thermal images of the lower lobes were continuously recorded from the bottom of organ chamber using infrared thermography. Lungs were perfused according to the Lund protocol. In the initial 1 h, lungs were gradually rewarmed by increasing the flow rate in a stepwise fashion. At 2 h, transplant suitability was decided, and lung tissue samples were collected to measure wet/dry (W/D). <h3>Results</h3> Lung surface temperatures of non-suitable cases (n = 6) were significantly lower than in suitable cases (n = 9) at 8 min (25.1 ± 0.6 vs. 27.8 ± 1.2°C, <i>P</i> < 0.001, cut-off = 26°C, AUC = 1.0, Figure A), while there was no difference between the two groups at 0-4 min and 12-120 min. There was a significant negative correlation between lung surface temperature at 8 min and W/D at 2 h in the lower lobes (R = -0.769, <i>P</i> < 0.001, Figure B). Lung thermography < 26°C at 8 min was significantly associated with a lower PaO₂/FiO₂, higher peak inspiratory pressure, higher lung weight gain, higher shunt ratio at 1 h and higher pulmonary vascular resistance at 8 min (<i>P</i> < 0.05, each). <h3>Conclusion</h3> These data suggest that a lung surface temperature of < 26°C at 8 min was significantly correlated with poor pulmonary function and transplant non-suitability. This finding indicates that lung surface temperature during the rewarming phase can be a good early predictor of pulmonary function in cellular EVLP and might be applicable for clinical EVLP.

Factors associated with prolonged weaning from mechanical ventilation in medical patients.

Background:Patients who need prolonged mechanical ventilation (MV) have high resource utilization and relatively poor outcomes. The pathophysiologic mechanisms leading to weaning failure in this group may be complex and multifactorial. The aim of this study was to investigate the factors associated with prolonged weaning based on the Weaning Outcome according to a New Definition (WIND) classification.Methods:This is a prospective observational study with consecutive adult patients receiving MV for at least two calendar days in medical intensive care units from 1 November 2017 to 30 September 2020. Eligible patients were divided in a non-prolonged weaning group, including short and difficult weaning, and in a prolonged weaning group according to the WIND classification. The risk factors at the time of first separation attempt associated with prolonged weaning were analyzed using a multivariable logistic regression model.Results:Of the total 915 eligible patients, 172 (18.8%) patients were classified as prolonged weaning. A higher proportion of the prolonged weaning group had previous histories of endotracheal intubation, chronic lung disease, and hematologic malignancies. When compared with the non-prolonged weaning group, the median duration of MV before the first spontaneous breathing trial (SBT) was longer and the proportion of tracheostomized patients was higher in prolonged weaning group. In addition, the prolonged weaning group used higher peak inspiratory pressures and yielded lower PaO2/FiO2 ratios at the day of the first SBT compared with the non-prolonged weaning group. In multivariate analyses, the duration of MV before first SBT (adjusted odds ratio [OR] = 1.14, 95% confidence interval [CI] = 1.06–1.22, p < 0.001), tracheostomy state (adjusted OR = 1.95, 95% CI = 1.04–3.63, p = 0.036), PaO2/FiO2 ratio (adjusted OR = 1.00, 95% CI = 0.99–1.00, p = 0.023), and need for renal replacement therapy (adjusted OR = 2.68, 95% CI = 1.16–6.19, p = 0.021) were independently associated with prolonged weaning. After the exclusion of patients who underwent tracheostomy before the SBTs, similar results were obtained.Conclusion:Longer duration of MV before the first SBT, tracheostomy status, poor oxygenation, and need for renal replacement therapy at the time of first SBT can predict prolonged weaning.Trial registration:ClinicalTrials.gov Identifier NCT05134467.

Risk factors associated with hypoxaemia in horses undergoing general anaesthesia: A retrospective study.

Hypoxaemia is a common concern during equine general anaesthesia. The prevalence and predictors of hypoxaemia in horses undergoing elective anaesthesia in particular are poorly documented. To determine and compare the prevalence of hypoxaemia (defined as PaO2 ≤80mm Hg, on the lowest value recorded) in horses undergoing anaesthesia for exploratory laparotomy and elective procedures, and to identify risk factors in both subpopulations. Retrospective cohort study. Data were collected from 774 records of 708 horses undergoing general anaesthesia between April 2017 and August 2020. Potential predictors of hypoxaemia in horses undergoing anaesthesia for exploratory laparotomy or elective procedures were investigated separately by univariable penalised maximum likelihood logistic regression, followed by multivariable analysis. The lowest recorded PaO2 was used as a single data point for the determination of hypoxaemia and arterial oxygen partial pressure to fractional inspired oxygen ratio analysis. Hypoxaemia was recorded in 23% horses undergoing exploratory laparotomy compared with 3.8% horses undergoing elective anaesthesia (P<.001). Multivariable analysis showed that weight above 550kg, large intestinal lesions, and peak inspiratory pressure (PIP) above 30cmH2 O were significantly associated with hypoxaemia in horses undergoing exploratory laparotomy. Soft tissue procedures and PIP >30cmH2 O were significantly associated with hypoxaemia during elective anaesthesia. This study only considered the minimum PaO2 recorded during anaesthesia. Duration and treatment of hypoxaemia were not considered. Based on the lowest PaO2 value during anaesthesia, in our population, horses undergoing anaesthesia for exploratory laparotomy were over six times more likely to become hypoxaemic than horses undergoing elective procedures. Bodyweight, type of procedure, and high PIP were predictors of hypoxaemia.

Ventilatory performance of AMBU® AuraGain™ and LMA® Supreme™ in laparoscopic surgery: A randomised controlled trial

The Ambu® AuraGain™ (Ambu A/S, Ballerup, Denmark) is a newer phthalate-free, single-use supraglottic device with the advantage of a facility for tracheal intubation if necessary intraoperatively. We compared the oropharyngeal leak pressures and other performance variables between the AMBU AuraGain and the LMA® Supreme™ (Teleflex Medical, Athlone, Co. Westmeath, Ireland) in patients undergoing laparoscopic cholecystectomy and preperitoneoscopic inguinal herniorrhaphy with carbon dioxide insufflation under controlled ventilation. We recruited 120 American Society of Anesthesiologists physical status class I-3 patients between the ages of 21 and 80 years undergoing laparoscopic cholecystectomy or preperitoneoscopic inguinal herniorrhaphy into this single-centre randomised controlled trial. The primary outcome measure was the oropharyngeal leak pressures. Secondary outcomes included insertion parameters, ventilatory characteristics and postoperative sequelae. The AuraGain had slightly but significantly higher oropharyngeal leak pressures than the LMA Supreme (mean (standard deviation) 26.1 (6.9) versus 21.4 (4.7) cmH2O, P < 0.010). The overall insertion success of the AuraGain was comparable to the LMA Supreme (AuraGain 58/60 (96.7%); LMA Supreme 56/59 (94.9%), P = 0.679). The AuraGain was deemed more difficult to insert than the LMA Supreme, with 26/60 (43.3%) of AuraGain insertions graded easy versus 48/59 (81.4%) of LMA Supreme, P < 0.001. The mean time to insertion of the AuraGain was slightly longer than the LMA Supreme, 32.2 (10.5) versus 28.3 (12.0) s, P < 0.001. Intraoperative device failure occurred following carbon dioxide insufflation in one AuraGain and three LMA Supremes, bringing the perioperative success rate of AuraGain and LMA Supreme to 95% and 89.8%, respectively, P = 0.322. No cases of regurgitation and aspiration occurred, and minor postoperative complications were similar. The AuraGain exhibited higher oropharyngeal leak pressures than the LMA Supreme, but was slightly more difficult to insert. The higher oropharyngeal leak pressures suggest that ventilation might be less affected by high peak inspiratory pressures when using the AuraGain than the LMA Supreme.

High Peak Inspiratory Pressures After a Change of Heat and Moisture Exchangers: A Case Series.

Elevated peak inspiratory pressures (PIPs) cause harm via hypoventilation, barotrauma, and hemodynamic instability. Heat and moisture exchangers (HMEs) are used during mechanical ventilation to prevent heat loss, dehydration of airway mucosa, and accumulation of dried secretions. Multiple reports detail sudden HME occlusions causing increased PIPs. We describe 4 cases of gradually increasing PIPs from progressive HME obstruction that occurred within 6 months of an institutional change to a newer model. HME obstruction should be considered when PIPs are elevated. Alternative heat and moisture preservation strategies should be contemplated, as HMEs increase airflow resistance and add another point of possible malfunction.

Nasopharyngeal tubes in pediatric anesthesia: Is the flow-dependent pressure drop across the tube suitable for calculating oropharyngeal pressure?

BackgroundNasopharyngeal tubes are useful in pediatric anesthesia for insufflating oxygen and anesthetics. During nasopharyngeal tube‐anesthesia, gas insufflation provides some positive oropharyngeal pressure that differs from the proximal airway pressure owing to the flow‐dependent pressure drop across the nasopharyngeal tube (ΔPNPT).AimsThis study aimed to investigate whether ΔPNPT could be used for calculating oropharyngeal pressure during nasopharyngeal tube‐assisted anesthesia.MethodsIn a physical model of nasopharyngeal tube‐anesthesia, using Rohrer's equation, we calculated ΔPNPT for three nasopharyngeal tubes (3.5, 4.0, and 5.0 mm inner diameter) under oxygen and several sevoflurane in oxygen combinations in two ventilatory scenarios (continuous positive airway pressure and intermittent positive pressure ventilation). We then calculated oropharyngeal pressure as proximal airway pressure minus ΔPNPT. Calculated and measured oropharyngeal pressure couples of values were compared with the root mean square deviation to assess accuracy. We also investigated whether oropharyngeal pressure accuracy depends on the nasopharyngeal tube diameter, flow rate, gas composition, and leak size. Using ΔPNPT charts, we tested whether ΔPNPT calculation was feasible in clinical practice.ResultsWhen we tested small‐diameter nasopharyngeal tubes at high‐flow or high‐peak inspiratory pressure, proximal airway pressure measurements markedly overestimated oropharyngeal pressure. Comparing measured and calculated maximum and minimum oropharyngeal pressure couples yielded root mean square deviations less than 0.5 cmH2O regardless of ventilatory modality, nasopharyngeal tube diameter, flow rate, gas composition, and leak size.ConclusionDuring nasopharyngeal tube‐assisted anesthesia, proximal airway pressure readings on the anesthetic monitoring machine overestimate oropharyngeal pressure especially for smaller‐diameter nasopharyngeal tubes and higher flow, and to a lesser extent for large leaks. Given the importance of calculating oropharyngeal pressure in guiding nasopharyngeal tube ventilation in clinical practice, we propose an accurate calculation using Rohrer's equation method, or approximating oropharyngeal pressure from flow and pressure readings on the anesthetic machine using the ΔPNPT charts.

Daily Practice of Mechanical Ventilation and Weaning in Turkish PICUs: A Multicenter Prospective Survey.

To investigate conventional mechanical ventilation weaning characteristics of patients requiring conventional mechanical ventilation support for greater than 48 hours within the PICU. The prospective observational multicenter cohort study was conducted at 15 hospitals. Data were being collected from November 2013 to June 2014, with two designated researchers from each center responsible for follow-up and data entry. Fifteen tertiary PICUs in Turkey. Patients between 1 month and 18 years old requiring conventional mechanical ventilation for greater than 48 hours were included. A single-center was not permitted to surpass 20% of the total sample size. Patients with no plans for conventional mechanical ventilation weaning were excluded. Conventional mechanical ventilation MEASUREMENTS AND MAIN RESULTS:: Pertinent variables included PICU and patient demographics, including clinical data, chronic diseases, comorbid conditions, and reasons for intubation. Conventional mechanical ventilation mode and weaning data were characterized by daily ventilator parameters and blood gases. Patients were monitored until hospital discharge. Of the 410 recruited patients, 320 were included for analyses. A diagnosis of sepsis requiring intubation and high initial peak inspiratory pressures correlated with a longer weaning period (mean, 3.65 vs 1.05-2.17 d; p < 0.001). Conversely, age, admission Pediatric Risk of Mortality III scores, days of conventional mechanical ventilation before weaning, ventilator mode, and chronic disease were not related to weaning duration. Pediatric patients requiring conventional mechanical ventilation with a diagnosis of sepsis and high initial peak inspiratory pressures may require longer conventional mechanical ventilation weaning prior to extubation. Causative factors and optimal weaning for this cohort needs further consideration.

Predictors of Bronchopulmonary Dysplasia in Saudi Preterm Infants

Background: Bronchopulmonary dysplasia (BPD) is a major cause of morbidity and mortality among preterm infants. Objective: To determine BPD prevalence and to identify factors that predict the development of BPD. Patients and Methods: We performed a retrospective cohort study of all neonates admitted to the neonatal intensive care unit (NICU) between 2009 and 2019 with gestational age (GA) less than 32 weeks and birth weight (BW) less than 1500 g. Results: A total of 637 preterm infants included in the study, of whom 194 (30.5%) infants developed BPD. Of the 194 preterm infants who developed BPD 89 (45.9 %) had mild, 59 (30.4%) had moderate and 46 (23.7%) had severe BPD. Multivariate analysis revealed that low GA (odds ratio [OR]: 0.62; 95% confidence interval [CI]: 0.43-0.98), low BW (OR: 20.6; 95% CI: 17.1-29.3), use of mechanical ventilation (OR: 1.07; 95% CI: 0.87-1.54), higher peak inspiratory pressure (PIP) (OR: 1.48; 95% CI: 1.44-1.91), higher fraction of inspired oxygen (FiO2) use (OR: 0.11; 95% CI: 0.05-0.19), duration of mechanical ventilation (OR: 3.56; 95% CI: 4.28-3.75) and frequent blood transfusion (OR: 0.65; 95% CI: 0.53-0.87) were identified as the principal risk factors for BPD. Conclusions: The prevalence of BPD among Saudi preterm infants was 30.5%. The most relevant predictors of BPD were GA, BW, mechanical ventilation, higher PIP, higher FiO2 use, duration of mechanical ventilation and frequent blood transfusion.