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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)., (© 2024. The Author(s).)

Background: Acute respiratory distress syndrome (ARDS) is highly heterogeneous, both in its clinical presentation and in the patient's physiological responses to changes in mechanical ventilator settings, such as PEEP. This study investigates the clinical efficacy of a physiological model-based ventilatory decision support system (DSS) to personalize ventilator therapy in ARDS patients., Methods: This international, multicenter, randomized, open-label study enrolled patients with ARDS during the COVID-19 pandemic. Patients were randomized to either receive active advice from the DSS (intervention) or standard care without DSS advice (control). The primary outcome was to detect a reduction in average driving pressure between groups. Secondary outcomes included several clinically relevant measures of respiratory physiology, ventilator-free days, time from control mode to support mode, number of changes in ventilator settings per day, percentage of time in control and support mode ventilation, ventilation- and device-related adverse events, and the number of times the advice was followed., Results: A total of 95 patients were randomized in this study. The DSS showed no significant effect on average driving pressure between groups. However, patients in the intervention arm had a statistically improved oxygenation index when in support mode ventilation (-1.41, 95% CI: -2.76, -0.08; p  = 0.0370). Additionally, the ventilatory ratio significantly improved in the intervention arm for patients in control mode ventilation (-0.63, 95% CI: -1.08, -0.17, p  = 0.0068). The application of the DSS led to a significantly increased number of ventilator changes for pressure settings and respiratory frequency., Conclusion: The use of a physiological model-based decision support system for providing advice on mechanical ventilation in patients with COVID-19 and non-COVID-19 ARDS showed no significant difference in driving pressure as a primary outcome measure. However, the application of approximately 60% of the DSS advice led to improvements in the patient's physiological state., Clinical Trial Registration: clinicaltrials.gov, NCT04115709., Competing Interests: SR and DK have previously been, but are no longer, shareholders of Mermaid Care A/S, who manufactured the decision support system presented here. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Patel, Mumby, Johnson, Handslip, Patel, Lee, Andersen, Falaschetti, Adcock, McAuley, Takata, Staudinger, Karbing, Jabaudon, Schellongowski and Rees.)

Background: Postoperative pulmonary complications can increase hospital length of stay, postoperative morbidity, and mortality. Although many factors can increase the risk of postoperative pulmonary complications, it is not known whether intraoperative ventilation/perfusion (V/Q) mismatch can be associated with an increased risk of postoperative pulmonary complications after major noncardiac surgery., Methods: This study enrolled patients undergoing general anesthesia for noncardiac surgery and evaluated intraoperative V/Q distribution using the automatic lung parameter estimator technique. The assessment was done after anesthesia induction, after 1 h from surgery start, and at the end of surgery. Demographic and procedural information were collected, and intraoperative ventilatory and hemodynamic parameters were measured at each timepoint. Patients were followed up for 7 days after surgery and assessed daily for postoperative pulmonary complication occurrence., Results: The study enrolled 101 patients with a median age of 71 [62 to 77] years, a body mass index of 25 [22.4 to 27.9] kg/m2, and a preoperative Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score of 41 [34 to 47]. Of these patients, 29 (29%) developed postoperative pulmonary complications, mainly acute respiratory failure (23%) and pleural effusion (11%). Patients with and without postoperative pulmonary complications did not differ in levels of shunt at T1 (postoperative pulmonary complications: 22.4% [10.4 to 35.9%] vs. no postoperative pulmonary complications:19.3% [9.4 to 24.1%]; P = 0.18) or during the protocol, whereas significantly different levels of high V/Q ratio were found during surgery (postoperative pulmonary complications: 13 [11 to 15] mmHg vs. no postoperative pulmonary complications: 10 [8 to 13.5] mmHg; P = 0.007) and before extubation (postoperative pulmonary complications: 13 [11 to 14] mmHg vs. no postoperative pulmonary complications: 10 [8 to 12] mmHg; P = 0.006). After adjusting for age, ARISCAT, body mass index, smoking, fluid balance, anesthesia type, laparoscopic procedure and surgery duration, high V/Q ratio before extubation was independently associated with the development of postoperative pulmonary complications (odds ratio, 1.147; 95% CI, 1.021 to 1.289; P = 0.02). The sensitivity analysis showed an E-value of 1.35 (CI, 1.11)., Conclusions: In patients with intermediate or high risk of postoperative pulmonary complications undergoing major noncardiac surgery, intraoperative V/Q mismatch is associated with the development of postoperative pulmonary complications. Increased high V/Q ratio before extubation is independently associated with the occurrence of postoperative pulmonary complications in the first 7 days after surgery., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc., on behalf of the American Society of Anesthesiologists.)

Background: Endotracheal suctioning causes discomfort, is associated with adverse effects, and is resource-demanding. An artificial secretion removal method, known as an automated cough, has been developed, which applies rapid, automated deflation, and inflation of the endotracheal tube cuff during the inspiratory phase of mechanical ventilation. This method has been evaluated in the hands of researchers but not when used by attending nurses. The aim of this study was to explore the efficacy of the method over the course of patient management as part of routine care., Methods: This prospective, longitudinal, interventional study recruited 28 subjects who were intubated and mechanically ventilated. For a maximum of 7 d and on clinical need for endotracheal suctioning, the automatic cough procedure was applied. The subjects were placed in a pressure-regulated ventilation mode with elevated inspiratory pressure, and automated cuff deflation and inflation were performed 3 times, with this repeated if deemed necessary. Success was determined by resolution of the clinical need for suctioning as determined by the attending nurse. Adverse effects were recorded., Results: A total of 84 procedures were performed. In 54% of the subjects, the artificial cough procedure was successful on > 70% of occasions, with 56% of all procedures considered successful. Ninety percent of all the procedures were performed in subjects who were spontaneously breathing and on pressure-support ventilation with peak inspiratory pressures of 20 cm H 2 O. Rates of adverse events were similar to those seen in the application of endotracheal suctioning., Conclusions: This study solely evaluated the efficacy of an automated artificial cough procedure, which illustrated the potential for reducing the need for endotracheal suctioning when applied by attending nurses in routine care., Competing Interests: Drs Karbing and Rees are shareholders of AW Technologies, who manufacture the TrachFlush system evaluated in this study. The other authors have disclosed no conflicts of interest., (Copyright © 2024 by Daedalus Enterprises.)

Invasive mechanical ventilation is a key supportive therapy for patients on intensive care. There is increasing emphasis on personalised ventilation strategies. Clinical decision support systems (CDSS) have been developed to support this. We conducted a narrative review to assess evidence that could inform device implementation. A search was conducted in MEDLINE (Ovid) and EMBASE. Twenty-nine studies met the inclusion criteria. Role allocation is well described, with interprofessional collaboration dependent on culture, nurse:patient ratio, the use of protocols, and perception of responsibility. There were no descriptions of process measures, quality metrics, or clinical workflow. Nurse-led weaning is well-described, with factors grouped by patient, nurse, and system. Physician-led weaning is heterogenous, guided by subjective and objective information, and 'gestalt'. No studies explored decision-making with CDSS. Several explored facilitators and barriers to implementation, grouped by clinician (facilitators: confidence using CDSS, retaining decision-making ownership; barriers: undermining clinician's role, ambiguity moving off protocol), intervention (facilitators: user-friendly interface, ease of workflow integration, minimal training requirement; barriers: increased documentation time), and organisation (facilitators: system-level mandate; barriers: poor communication, inconsistent training, lack of technical support). One study described factors that support CDSS implementation. There are gaps in our understanding of ventilation practice. A coordinated approach grounded in implementation science is required to support CDSS implementation. Future research should describe factors that guide clinical decision-making throughout mechanical ventilation, with and without CDSS, map clinical workflow, and devise implementation toolkits. Novel research design analogous to a learning organisation, that considers the commercial aspects of device design, is required., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Introduction: Hypoxic pulmonary vasoconstriction (HPV) can be a challenging clinical problem. It is not fully elucidated where in the circulation the regulation of resistance takes place. It is often referred to as if it is in the arteries, but we hypothesized that it is in the venous side of the pulmonary circulation., Methods: In an open thorax model, pigs were treated with a veno-venous extra corporeal membrane oxygenator to either oxygenate or deoxygenate blood passing through the pulmonary vessels. At the same time the lungs were ventilated with extreme variations of inspired air from 5% to 100% oxygen, making it possible to make combinations of high and low oxygen content through the pulmonary circulation. A flow probe was inserted around the main pulmonary artery and catheters in the pulmonary artery and in the left atrium were used for pressure monitoring and blood tests. Under different combinations of oxygenation, pulmonary vascular resistance (PVR) was calculated., Results: With unchanged level of oxygen in the pulmonary artery and reduced inspired oxygen fraction lowering oxygen tension from 29 to 6.7 kPa in the pulmonary vein, PVR was doubled. With more extreme hypoxia PVR suddenly decreased. Combinations with low oxygenation in the pulmonary artery did not systematic influence PVR if there was enough oxygen in the inspired air and in the pulmonary veins., Discussion: The impact of hypoxia occurs from the alveolar level and forward with the blood flow. The experiments indicated that the regulation of PVR is mediated from the venous side., (© 2024 The Authors. Animal Models and Experimental Medicine published by John Wiley & Sons Australia, Ltd on behalf of The Chinese Association for Laboratory Animal Sciences.)

Background: Flexible bronchoscopy procedures require detailed anatomical knowledge and advanced technical skills. Simulation-based training offers a patient-safe training environment that can be more efficient than patient-based training. Physical models are cheaper than virtual reality simulators and allow trainees to be acquainted with the equipment used in the clinic. The choice of a physical model for training depends on the local context. The aim of this study was to compare four different bronchoscopy models for flexible bronchoscopy training., Methods: The BronchoBoy manikin, the Koken manikin, a human cadaver, and a preserved porcine lung were included in the study. Seven physicians experienced in bronchoscopy performed a bronchoscopic airway inspection, bronchoalveolar lavage (BAL), and tissue sampling on all four models with performance evaluated by observation and participant evaluation of models by questionnaire., Results: Nineteen segments were identified in all human anatomy models, and the only significant difference found was that only the Thiel embedded cadaver allowed all participants to enter RB1 with an instrument in the working channel (p = 0.001). The Thiel embedded cadaver and the BronchoBoy manikin had low fluid return on BAL (22 and 52 ml), whereas the Koken manikin and the preserved porcine lung had high return (132 and 134 ml), (p = 0.017). Tissue samplings were only completed in the preserved porcine lung and the Thiel embedded cadaver (p < 0.001)., Conclusions: An anatomically correct bronchoscopy is best simulated with the Koken manikin or the Thiel embedded cadaver. Bronchoalveolar lavage should be simulated with the Koken manikin or the preserved porcine lung. Tissue sampling procedures are best simulated using the Thiel embedded cadaver or the preserved porcine lung., (© 2024. The Author(s).)

Background: 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., Methods: 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., Results: 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 H 2 O) and 83% at high settings (peak inspiratory pressure 25.6 ± 3.6 cm H 2 O). The Critical-Care Pain Observation Tool category remained unchanged in 30 procedures (77%), improved in 7 (18%), and deteriorated in 2 (5%)., Conclusions: 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., Competing Interests: Drs Rees and Karbing are shareholders of AW Technologies, which manufactures the TrachFlush system evaluated in this study. The other authors have disclosed no conflicts of interest., (Copyright © 2023 by Daedalus Enterprises.)

Background: Laparoscopic surgery and Trendelenburg position may affect the respiratory function and alter the gas exchange. Further the reduction of the lung volumes may contribute to the development of expiratory flow limitation (EFL). The latter is associated with an increased risk of postoperative pulmonary complications. Our aim was to investigate the incidence of EFL and to evaluate its effect on pulmonary function and intraoperative V/Q mismatch., Methods: This is a prospective study on patients undergoing elective laparoscopic gynecological surgery. We evaluated respiratory mechanics, V/Q mismatch and presence of EFL after anesthesia induction, during pneumoperitoneum and Trendelenburg position and at the end of surgery. Intraoperative gas exchange and hemodynamic were also recorded. Clinical data were collected until seven days after surgery to evaluate the onset of pulmonary postoperative complications (PPCs)., Results: Among the 66 patients enrolled, 25/66 (38%) exhibited EFL during surgery, of whom 10/66 (15%) after anesthesia induction, and the remaining 15 patients after pneumoperitoneum and Trendelenburg position. Median PEEP able to reverse flow limitation was 7 [7-10] cmH2O after anesthesia induction and 9 [8-15] cmH2O after pneumoperitoneum and Trendelenburg position. Patients with EFL had significantly higher shunt (17 [2-25] vs. 9 [1-19]; P=0.05), low V̇/Q̇ (27 [20-70] vs. 15 [10-22]; P=0.05) and high V̇/Q̇ (10 [7-14] vs. 6 [4-7]; P=0.024). At the end of surgery, only high V/Q was significantly higher in EFL patients. Further, they exhibited higher incidence of postoperative pulmonary complication (48% (12/25) vs. 15% (6/41), P=0.005), hypoxemia and hypercapnia (80% [20/25] vs. 32% [13/41]; P<0.001)., Conclusions: Expiratory flow limitation is a common phenomenon during gynecological laparoscopic surgery associated with worsen gas exchange, increased V/Q mismatch and altered lung mechanics. Our study showed that patients experiencing EFL during surgery showed a higher risk for PPCs.

Background: Diaphragmatic dysfunction is well documented in patients receiving mechanical ventilation. Inspiratory muscle training (IMT) has been used to facilitate weaning by strengthening the inspiratory muscles, yet the optimal approach remains uncertain. Whilst some data on the metabolic response to whole body exercise in critical care exist, the metabolic response to IMT in critical care is yet to be investigated. This study aimed to quantify the metabolic response to IMT in critical care and its relationship to physiological variables., Methods: We conducted a prospective observational study on mechanically ventilated patients ventilated for ≥ 72 h and able to participate in IMT in a medical, surgical, and cardiothoracic intensive care unit. 76 measurements were taken on 26 patients performing IMT using an inspiratory threshold loading device at 4 cmH 2 O, and at 30, 50 and 80% of their negative inspiratory force (NIF). Oxygen consumption (VO 2 ) was measured continuously using indirect calorimetry., Results: First session mean (SD) VO 2 was 276 (86) ml/min at baseline, significantly increasing to 321 (93) ml/min, 333 (92) ml/min, 351(101) ml/min and 388 (98) ml/min after IMT at 4 cmH 2 O and 30, 50 and 80% NIF, respectively (p = 0.003). Post hoc comparisons revealed significant differences in VO 2 between baseline and 50% NIF and baseline and 80% NIF (p = 0.048 and p = 0.001, respectively). VO 2 increased by 9.3 ml/min for every 1 cmH 2 O increase in inspiratory load from IMT. Every increase in P/F ratio of 1 decreased the intercept VO 2 by 0.41 ml/min (CI - 0.58 to - 0.24 p < 0.001). NIF had a significant effect on the intercept and slope, with every 1 cmH 2 O increase in NIF increasing intercept VO 2 by 3.28 ml/min (CI 1.98-4.59 p < 0.001) and decreasing the dose-response slope by 0.15 ml/min/cmH 2 O (CI - 0.24 to - 0.05 p = 0.002)., Conclusions: IMT causes a significant load-dependent increase in VO 2 . P/F ratio and NIF impact baseline VO 2 . The dose-response relationship of the applied respiratory load during IMT is modulated by respiratory strength. These data may offer a novel approach to prescription of IMT., Take Home Message: The optimal approach to IMT in ICU is uncertain; we measured VO 2 at different applied respiratory loads to assess whether VO 2 increased proportionally with load and found VO 2 increased by 9.3 ml/min for every 1 cmH 2 O increase in inspiratory load from IMT. Baseline NIF has a significant effect on the intercept and slope, participants with a higher baseline NIF have a higher resting VO 2 but a less pronounced increase in VO 2 as the inspiratory load increases; this may offer a novel approach to IMT prescription. Trial registration ClinicalTrials.gov, registration number: NCT05101850. Registered on 28 September 2021, https://clinicaltrials.gov/ct2/show/NCT05101850., (© 2023. The Author(s).)

Increased ventilatory work beyond working capacity of the respiratory muscles can induce fatigue, resulting in limited respiratory muscle endurance (T lim ). Previous resistive breathing investigations all applied square wave inspiratory pressure as fatigue-inducing pattern. Spontaneous breathing pressure pattern more closely approximate a triangle waveform. This study aimed at comparing T lim , maximal inspiratory pressure (PI max ), and metabolism between square and triangle wave breathing. Eight healthy subjects (Wei = 76 ± 10 kg, H = 181 ± 7.9 cm, age = 33.5 ± 4.8 years, sex [F/M] = 1/7) completed the study, comprising two randomized matched load resistive breathing trials with square and triangle wave inspiratory pressure waveform. T lim decreased with a mean difference of 8 ± 7.2 min (p = 0.01) between square and triangle wave breathing. PI max was reduced following square wave (p = 0.04) but not for triangle wave breathing (p = 0.88). Higher VO 2 was observed in the beginning and end for the triangle wave breathing compared with the square wave breathing (p = 0.036 and p = 0.048). Despite higher metabolism, T lim was significantly longer in triangle wave breathing compared with square wave breathing, showing that the pressure waveform has an impact on the function and endurance of the respiratory muscles., (© 2023 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Background: COVID-19-related ARDS is characterized by severe hypoxemia with initially preserved lung compliance and impaired ventilation/perfusion (V̇/Q̇) matching. PEEP can increase end-expiratory lung volume, but its effect on V̇/Q̇ mismatch in COVID-19-related ARDS is not clear., Methods: We enrolled intubated and mechanically ventilated subjects with COVID-19 ARDS and used the automatic lung parameter estimator (ALPE) to measure V̇/Q̇. Respiratory mechanics measurements, shunt, and V̇/Q̇ mismatch (low V̇/Q̇ and high V̇/Q̇) were collected at 3 PEEP levels (clinical PEEP = intermediate PEEP, low PEEP [clinical - 50%], and high PEEP [clinical + 50%]). A mixed-effect model was used to evaluate the impact of PEEP on V̇/Q̇. We also investigated if PEEP might have a different effect on V̇/Q̇ mismatch in 2 different respiratory mechanics phenotypes, that is, high elastance/low compliance (phenotype H) and low elastance/high compliance (phenotype L)., Results: Seventeen subjects with COVID-related ARDS age 66 [60-71] y with a P aO 2 /F IO 2 of 141 ± 74 mm Hg were studied at low PEEP = 5.6 ± 2.2 cm H 2 O, intermediate PEEP = 10.6 ± 3.8 cm H 2 O, and high PEEP = 15 ± 5 cm H 2 O. Shunt, low V̇/Q̇, high V̇/Q̇, and alveolar dead space were not significantly influenced, on average, by PEEP. Respiratory system compliance decreased significantly when increasing PEEP without significant variation of P aO 2 /F IO 2 ( P = .26). In the 2 phenotypes, PEEP had opposite effects on shunt, with a decrease in the phenotype L and an increase in phenotype H ( P = .048)., Conclusions: In subjects with COVID-related ARDS placed on invasive mechanical ventilation for > 48 h, PEEP had a heterogeneous effect on V̇/Q̇ mismatch and, on average, higher levels were not able to reduce shunt. The subject's compliance could influence the effect of PEEP on V̇/Q̇ mismatch since an increased shunt was observed in subjects with lower compliance, whereas the opposite occurred in those with higher compliance., Competing Interests: Drs Karbing and Rees disclose relationships with Mermaid Care. The remaining authors have disclosed no conflicts of interest., (Copyright © 2023 by Daedalus Enterprises.)

How to deliver best care in various clinical settings remains a vexing problem. All pertinent healthcare-related questions have not, cannot, and will not be addressable with costly time- and resource-consuming controlled clinical trials. At present, evidence-based guidelines can address only a small fraction of the types of care that clinicians deliver. Furthermore, underserved areas rarely can access state-of-the-art evidence-based guidelines in real-time, and often lack the wherewithal to implement advanced guidelines. Care providers in such settings frequently do not have sufficient training to undertake advanced guideline implementation. Nevertheless, in advanced modern healthcare delivery environments, use of eActions (validated clinical decision support systems) could help overcome the cognitive limitations of overburdened clinicians. Widespread use of eActions will require surmounting current healthcare technical and cultural barriers and installing clinical evidence/data curation systems. The authors expect that increased numbers of evidence-based guidelines will result from future comparative effectiveness clinical research carried out during routine healthcare delivery within learning healthcare systems., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

This paper provides a review of a selection of papers published in the Journal of Clinical Monitoring and Computing in 2020 and 2021 highlighting what is new within the field of respiratory monitoring. Selected papers cover work in pulse oximetry monitoring, acoustic monitoring, respiratory system mechanics, monitoring during surgery, electrical impedance tomography, respiratory rate monitoring, lung ultrasound and detection of patient-ventilator asynchrony., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Systems aiding in selecting the correct settings for mechanical ventilation should visualize patient information at an appropriate level of complexity, so as to reduce information overload and to make reasoning behind advice transparent. Metaphor graphics have been applied to this effect, but these have largely been used to display diagnostic and physiologic information, rather than the clinical decision at hand. This paper describes how the conflicting goals of mechanical ventilation can be visualized and applied in making decisions. Data from previous studies are analyzed to assess whether visual patterns exist which may be of use to the clinical decision maker., Materials and Methods: The structure and screen visualizations of a commercial clinical decision support system (CDSS) are described, including the visualization of the conflicting goals of mechanical ventilation represented as a hexagon. Retrospective analysis is performed on 95 patients from 2 previous clinical studies applying the CDSS, to identify repeated patterns of hexagon symbols., Results: Visual patterns were identified describing optimal ventilation, over and under ventilation and pressure support, and over oxygenation, with these patterns identified for both control and support modes of mechanical ventilation. Numerous clinical examples are presented for these patterns illustrating their potential interpretation at the bedside., Conclusions: Visual patterns can be identified which describe the trade-offs required in mechanical ventilation. These may have potential to reduce information overload and help in simple and rapid identification of sub-optimal settings., (© 2022. The Author(s).)

Background: The acute respiratory distress syndrome (ARDS) occurs in response to a variety of insults, and mechanical ventilation is life-saving in this setting, but ventilator-induced lung injury can also contribute to the morbidity and mortality in the condition. The Beacon Caresystem is a model-based bedside decision support system using mathematical models tuned to the individual patient's physiology to advise on appropriate ventilator settings. Personalised approaches using individual patient description may be particularly advantageous in complex patients, including those who are difficult to mechanically ventilate and wean, in particular ARDS., Methods: We will conduct a multi-centre international randomised, controlled, allocation concealed, open, pragmatic clinical trial to compare mechanical ventilation in ARDS patients following application of the Beacon Caresystem to that of standard routine care to investigate whether use of the system results in a reduction in driving pressure across all severities and phases of ARDS., Discussion: Despite 20 years of clinical trial data showing significant improvements in ARDS mortality through mitigation of ventilator-induced lung injury, there remains a gap in its personalised application at the bedside. Importantly, the protective effects of higher positive end-expiratory pressure (PEEP) were noted only when there were associated decreases in driving pressure. Hence, the pressures set on the ventilator should be determined by the diseased lungs' pressure-volume relationship which is often unknown or difficult to determine. Knowledge of extent of recruitable lung could improve the ventilator driving pressure. Hence, personalised management demands the application of mechanical ventilation according to the physiological state of the diseased lung at that time. Hence, there is significant rationale for the development of point-of-care clinical decision support systems which help personalise ventilatory strategy according to the current physiology. Furthermore, the potential for the application of the Beacon Caresystem to facilitate local and remote management of large numbers of ventilated patients (as seen during this COVID-19 pandemic) could change the outcome of mechanically ventilated patients during the course of this and future pandemics., Trial Registration: ClinicalTrials.gov identifier NCT04115709. Registered on 4 October 2019, version 4.0., (© 2022. The Author(s).)

During one-lung ventilation (OLV), titrating the positive end-expiratory pressure (PEEP) to target a low driving pressure (∆P) could reduce postoperative pulmonary complications. However, it is unclear how to conduct PEEP titration: by stepwise increase starting from zero PEEP (PEEP INCREMENTAL ) or by stepwise decrease after a lung recruiting manoeuvre (PEEP DECREMENTAL ). In this randomized trial, we compared the physiological effects of these two PEEP titration strategies on respiratory mechanics, ventilation/perfusion mismatch and gas exchange. Patients undergoing video-assisted thoracoscopic surgery in OLV were randomly assigned to a PEEP INCREMENTAL or PEEP DECREMENTAL strategy to match the lowest ∆P. In the PEEP INCREMENTAL group, PEEP was stepwise titrated from ZEEP up to 16 cm H 2 O, whereas in the PEEP DECREMENTAL group PEEP was decrementally titrated, starting from 16 cm H 2 O, immediately after a lung recruiting manoeuvre. Respiratory mechanics, ventilation/perfusion mismatch and blood gas analyses were recorded at baseline, after PEEP titration and at the end of surgery. Sixty patients were included in the study. After PEEP titration, shunt decreased similarly in both groups, from 50 [39-55]% to 35 [28-42]% in the PEEP INCREMENTAL and from 45 [37-58]% to 33 [25-45]% in the PEEP DECREMENTAL group (both p < 0.001 vs baseline). The resulting ∆P, however, was lower in the PEEP DECREMENTAL than in the PEEP INCREMENTAL group (8 [7-11] vs 10 [9-11] cm H 2 O; p = 0.03). In the PEEP DECREMENTAL group the PaO 2 / FIO 2 ratio increased significantly after intervention (from 140 [99-176] to 186 [152-243], p < 0.001). Both the PEEP INCREMENTAL and the PEEP DECREMENTAL strategies were able to decrease intraoperative shunt, but only PEEP DECREMENTAL improved oxygenation and lowered intraoperative ΔP.Clinical trial number NCT03635281; August 2018; "retrospectively registered"., (© 2020. Springer Nature B.V.)

Clinical decision-making is based on knowledge, expertise, and authority, with clinicians approving almost every intervention-the starting point for delivery of "All the right care, but only the right care," an unachieved healthcare quality improvement goal. Unaided clinicians suffer from human cognitive limitations and biases when decisions are based only on their training, expertise, and experience. Electronic health records (EHRs) could improve healthcare with robust decision-support tools that reduce unwarranted variation of clinician decisions and actions. Current EHRs, focused on results review, documentation, and accounting, are awkward, time-consuming, and contribute to clinician stress and burnout. Decision-support tools could reduce clinician burden and enable replicable clinician decisions and actions that personalize patient care. Most current clinical decision-support tools or aids lack detail and neither reduce burden nor enable replicable actions. Clinicians must provide subjective interpretation and missing logic, thus introducing personal biases and mindless, unwarranted, variation from evidence-based practice. Replicability occurs when different clinicians, with the same patient information and context, come to the same decision and action. We propose a feasible subset of therapeutic decision-support tools based on credible clinical outcome evidence: computer protocols leading to replicable clinician actions (eActions). eActions enable different clinicians to make consistent decisions and actions when faced with the same patient input data. eActions embrace good everyday decision-making informed by evidence, experience, EHR data, and individual patient status. eActions can reduce unwarranted variation, increase quality of clinical care and research, reduce EHR noise, and could enable a learning healthcare system., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Dietary nitrate (NO 3 - ) supplementation via beetroot juice (BR) has been reported to lower oxygen cost (i.e., increased exercise efficiency) and speed up oxygen uptake (VO 2 ) kinetics in untrained and moderately trained individuals, particularly during conditions of low oxygen availability (i.e., hypoxia). However, the effects of multiple-day, high dose (12.4 mmol NO 3- per day) BR supplementation on exercise efficiency and VO 2 kinetics during normoxia and hypoxia in well-trained individuals are not resolved. In a double-blinded, randomized crossover study, 12 well-trained cyclists (66.4 ± 5.3 ml min -1 ∙kg -1 ) completed three transitions from rest to moderate-intensity (~70% of gas exchange threshold) cycling in hypoxia and normoxia with supplementation of BR or nitrate-depleted BR as placebo. Continuous measures of VO 2 and muscle (vastus lateralis) deoxygenation (ΔHHb, using near-infrared spectroscopy) were acquired during all transitions. Kinetics of VO 2 and deoxygenation (ΔHHb) were modeled using mono-exponential functions. Our results showed that BR supplementation did not alter the primary time constant for VO 2 or ΔHHb during the transition from rest to moderate-intensity cycling. While BR supplementation lowered the amplitude of the VO 2 response (2.1%, p = 0.038), BR did not alter steady state VO 2 derived from the fit (p = 0.258), raw VO 2 data (p = 0.231), moderate intensity exercise efficiency (p = 0.333) nor steady state ΔHHb (p = 0.224). Altogether, these results demonstrate that multiple-day, high-dose BR supplementation does not alter exercise efficiency or oxygen uptake kinetics during normoxia and hypoxia in well-trained athletes., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Introduction: Automated systems for ventilator management to date have been either fully heuristic rule-based systems or based on a combination of simple physiological models and rules. These have been shown to reduce the duration of mechanical ventilation in simple to wean patients. At present, there are no published studies that evaluate the effect of systems that use detailed physiological descriptions of the individual patient.The BEACON Caresystem is a model-based decision support system that uses mathematical models of patients' physiology in combination with models of clinical preferences to provide advice on appropriate ventilator settings. An individual physiological description may be particularly advantageous in selecting the appropriate therapy for a complex, heterogeneous, intensive care unit (ICU) patient population., Methods and Analysis: Intenive Care weaning (iCareWean) is a single-blinded, multicentre, prospective randomised control trial evaluating management of mechanical ventilation as directed by the BEACON Caresystem compared with that of current care, in the general intensive care setting. The trial will enrol 274 participants across multiple London National Health Service ICUs. The trial will use a primary outcome of duration of mechanical ventilation until successful extubation., Ethics and Dissemination: Safety oversight will be under the direction of an independent committee of the study sponsor. Study approval was obtained from the regional ethics committee of the Health Research Authority (HRA), (Research Ethic Committee (REC) reference: 17/LO/0887. Integrated Research Application System (IRAS) reference: 226610. Results will be disseminated through international critical care conference/symposium and publication in peer-reviewed journal., Trial Registration Number: ClinicalTrials.gov under NCT03249623. This research is registered with the National Institute for Health Research under CPMS ID: 34831., Competing Interests: Competing interests: SR and DSK are minor shareholders of Mermaid Care A/S who manufacture the Beacon Caresystem. They have also acted as consultants for Mermaid Care A/S. SR is an unpaid board member of Mermaid Care A/S., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.)

The purpose of this study was to investigate the correlation between the seismocardiogram and cardiorespiratory fitness. Cardiorespiratory fitness can be estimated as VO 2 max using non-exercise algorithms, but the results can be inaccurate. Healthy subjects were recruited for this study. Seismocardiogram and electrocardiogram were recorded at rest. VO 2 max was measured during a maximal effort cycle ergometer test. Amplitudes and timing intervals were extracted from the seismocardiogram and used in combination with demographic data in a non-exercise prediction model for VO 2 max. 26 subjects were included, 17 females. Mean age: 38.3±9.1 years. The amplitude following the aortic valve closure derived from the seismocardiogram had a significant correlation of 0.80 (p<0.001) to VO 2 max. This feature combined with age, sex and BMI in the prediction model, yields a correlation to VO 2 max of 0.90 (p<0.001, 95% CI: 0.83-0.94) and a standard error of the estimate of 3.21 mL·kg -1 ·min -1  . The seismocardiogram carries information about the cardiorespiratory fitness. When comparing to other non-exercise models the proposed model performs better, even after cross validation. The model is limited when tracking changes in VO 2 max. The method could be used in the clinic for a more accurate estimation of VO 2 max compared to current non-exercise methods., Competing Interests: KS, SES, JJS and PS are shareholders in VentriJect ApS. The company uses a method similar to the one described in this article in a commercial product. The study was not financially supported by VentriJect ApS., (© Georg Thieme Verlag KG Stuttgart · New York.)

This paper reviews 28 papers or commentaries published in Journal of Clinical Monitoring and Computing in 2018 and 2019, within the field of respiration. Papers were published covering endotracheal tube cuff pressure monitoring, ventilation and respiratory rate monitoring, lung mechanics monitoring, gas exchange monitoring, CO 2 monitoring, lung imaging, and technologies and strategies for ventilation management.

Background: Several studies have found only a weak to moderate correlation between oxygenation and lung aeration in response to changes in PEEP. This study aimed to investigate the association between changes in shunt, low and high ventilation/perfusion (V/Q) mismatch, and computed tomography-measured lung aeration following an increase in PEEP in patients with ARDS., Methods: In this preliminary study, 12 ARDS patients were subjected to recruitment maneuvers followed by setting PEEP at 5 and then either 15 or 20 cmH 2 O. Lung aeration was measured by computed tomography. Values of pulmonary shunt and low and high V/Q mismatch were calculated by a model-based method from measurements of oxygenation, ventilation, and metabolism taken at different inspired oxygen levels and an arterial blood gas sample., Results: Increasing PEEP resulted in reduced values of pulmonary shunt and the percentage of non-aerated tissue, and an increased percentage of normally aerated tissue (p < 0.05). Changes in shunt and normally aerated tissue were significantly correlated (r = - 0.665, p = 0.018). Three distinct responses to increase in PEEP were observed in values of shunt and V/Q mismatch: a beneficial response in seven patients, where shunt decreased without increasing high V/Q; a detrimental response in four patients where both shunt and high V/Q increased; and a detrimental response in a patient with reduced shunt but increased high V/Q mismatch. Non-aerated tissue decreased with increased PEEP in all patients, and hyperinflated tissue increased only in patients with a detrimental response in shunt and V/Q mismatch., Conclusions: The results show that improved lung aeration following an increase in PEEP is not always consistent with reduced shunt and V/Q mismatch. Poorly matched redistribution of ventilation and perfusion, between dependent and non-dependent regions of the lung, may explain why patients showed detrimental changes in shunt and V/Q mismatch on increase in PEEP, despite improved aeration., Trial Registration: ClinicalTrails.gov, NCT04067154. Retrospectively registered on August 26, 2019.

Background: Indirect calorimetry (IC) is considered the accurate way of measuring energy expenditure (EE). IC devices often apply the Haldane transformation, introducing errors at inspiratory oxygen fraction (FiO 2 ) >60%. The aim was to assess measurement reliability and agreement between an unevaluated IC (device 2) (Beacon Caresystem, Mermaid Care A/S, Noerresundby, Denmark) not using Haldane transformation and an IC that does (device 1) (Ecovx, GE, Helsinki, Finland) at varying FiO 2 ., Methods: Twenty healthy male subjects participated, with 16 completing the study (33 ± 9 years, 83.3 ± 16 kg, 1.83 ± 0.08 m). Subjects were mechanically ventilated in pressure support (3cmH 2 O; positive end-expiratory pressure: 3cmH 2 O) at FiO 2 of 21%, 50%, 85%, and 21% for 15 minutes at each FiO 2 . Mean EE, oxygen consumption (VO 2 ), and CO 2 production (VCO 2 ) were compared within and between devices across FiO 2 levels., Results: Device 2 showed within-device EE significant differences at 21% vs 50% FiO 2 and device 1 for VCO 2 at 50% vs. 85% FiO 2 . For all variables, both devices showed reliable measurements at 21% and 50% FiO 2 , but at 85%, FiO 2 bias and limits of agreement increased. Between devices, there were significant differences for EE at both 21% and 85% FiO 2 for VO 2 and for VCO 2 at 85% FiO 2 ., Conclusion: Both systems measured EE, VO 2 , and VCO 2 at 21%-85% FiO 2 reliably but with bias at 85% FiO 2 . The devices were in agreement at 21% and 50% FiO 2 , but further studies need to confirm accuracy at high FiO 2 ., (© 2019 American Society for Parenteral and Enteral Nutrition.)

The purpose was to develop a bench setup for testing a decision support system (DSS) for proportional assist ventilation (PAV). The test setup was based on a patient simulator connected to a mechanical ventilator with the DSS measurement sensors connected to the respiratory circuit. A test case was developed with parameters of lung mechanics reflecting a patient with mild acute respiratory distress syndrome. Five experiments were performed starting at different levels of percentage support (%Supp) and continuing until the DSS advised to remain at current settings. Final advice ranged from %Supp of 50-70%, indicating some dependence of baseline level, but with resulting patient effort estimates indicating that this may not be clinically important. Further studies are required of test cases reflecting different patient types and in patients.

Dietary nitrate (NO 3 - ) supplementation via beetroot juice (BR) is known to improve endurance performance in untrained and moderately trained individuals. However, conflicting results exist in well-trained individuals. Evidence suggests that the effects of NO 3 - are augmented during conditions of reduced oxygen availability (e.g., hypoxia), thereby increasing the probability of performance improvements for well-trained athletes in hypoxia vs. normoxia. This randomized, double-blinded, counterbalanced-crossover study examined the effects of 7 days of BR supplementation with 12.4 mmol NO 3 - per day on 10-km cycling time trial (TT) performance in 12 well-trained cyclists in normoxia (N) and normobaric hypoxia (H). Linear mixed models for repeated measures revealed increases in plasma NO 3 - and NO 2 - after supplementation with BR (both p < 0.001). Further, TT performance increased with BR supplementation (∼1.6%, p < 0.05), with no difference between normoxia and hypoxia (p = 0.92). For respiratory variables there were significant effects of supplementation on VO 2 (p < 0.05) and VE (p < 0.05) such that average VO 2 and VE during the TT increased with BR, with no difference between normoxia and hypoxia (p ≥ 0.86). We found no effect of supplementation on heart rate, oxygen saturation or muscle oxygenation during the TT. Our results provide new evidence that chronic high-dose NO 3 - supplementation improves cycling performance of well-trained cyclists in both normoxia and hypoxia., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: To assess whether a clinical decision support system (CDSS) suggests PS and FIO 2 maintaining appropriate breathing effort, and minimizing FIO 2 ., Materials: Prospective, cross-over study in PS ventilated ICU patients. Over support (150% baseline) and under support (50% baseline) were applied by changing PS (15 patients) or PEEP (8 patients). CDSS advice was followed. Tension time index of inspiratory muscles (TTies), respiratory and metabolic variables were measured., Results: PS over support (median 8.0 to 12.0 cmH 2 O) reduced respiratory muscle activity (TTies 0.090 ± 0.028 to 0.049 ± 0.030; p < .01), and tended to increase tidal volume (VT: 8.6 ± 3.0 to 10.1 ± 2.9 ml/kg; p = .08). CDSS advice reduced PS (6.0 cmH 2 O, p = .005), increased TTies (0.076 ± 0.038, p < .01), and tended to reduce VT (8.9 ± 2.4 ml/kg, p = .08). PS under support (12.0 to 4.0 cmH 2 O) slightly increased respiratory muscle activity, (TTies to 0.120 ± 0.044; p = .007) with no significant CDSS advice. CDSS advice reduced FIO 2 by 12-14% (p = .005), resulting in median SpO 2  = 96% (p < .02). PEEP changes did not result in changes in physiological variables, or CDSS advice., Conclusion: The CDSS advised on low values of PS often not prohibiting extubation, while acting to preserve respiratory muscle function and preventing passive lung inflation. CDSS advice minimized FIO 2 maintaining SpO 2 at safe and beneficial values., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The relationship between the date of birth and expertise in various sports among both elite and youth level athletes is well established, and known as the relative age effect (RAE). However, new results in for example Canadian Hockey and British cricket and rugby have indicated a reversal of RAE among selected talents where the youngest athletes are more likely to remain selected than their older peers. As such, RAE may therefore depend on the age and the level of competition. The purpose of this study was therefore to analyse RAE from the youth to senior national level in a sample of successful Danish male national teams. The sample included 244 players from Danish under-19, under-21 and senior national levels. These players have been part of successful teams, winning 18 medals at 24 youth European and World championships and 8 medals during 12 years at the senior level. The results showed a significant RAE on both youth and national levels. However, RAE was less marked from the under-19 to under-21 and further to the senior national level. Results show that at the national youth level talent selection favours the relatively older players, of whom a larger proportion fails to be re-selected to the senior level compared to their younger peers. RAE appears to play a central and reversing role in the identification and re-selection in Danish male handball. The results also show that the presence of both a constant and constituent year structure affects RAE, even when introduced at late adolescence.

Objectives: To evaluate the physiologic effects of applying advice on mechanical ventilation by an open-loop, physiologic model-based clinical decision support system., Design: Prospective, observational study., Setting: University and Regional Hospitals' ICUs., Patients: Varied adult ICU population., Interventions: Advice were applied if accepted by physicians for a period of up to 4-8 hours., Measurements and Main Results: Seventy-two patients were included for data analysis. Acceptance of advice was high with 95.7% of advice applied. In 41 patients in pressure support ventilation, following system advice led to significant decrease in PS, with PS reduced below 8 cm H2O in 15 patients (37%), a level not prohibiting extubation. Fraction of end-tidal CO2 values did not change, and increase in respiratory rate/VT was within clinical limits, indicating that in general, the system maintained appropriate patient breathing effort. In 31 patients in control mode ventilation, pressure control and tidal volume settings were decreased significantly, with tidal volume reduced below 8 mL/kg predicted body weight in nine patients (29%). Minute ventilation was maintained by a significant increase in respiratory rate. Significant reductions in FIO2 were seen on elevated baseline median values of 50% in both support and control mode-ventilated patients, causing clinically acceptable reductions in oxygen saturation., Conclusions: The results indicate that during a short period, the clinical decision support system provided appropriate suggestions of mechanical ventilation in a varied ICU population, significantly reducing ventilation to levels which might be considered safe and beneficial.

This paper reviews 32 papers or commentaries published in Journal of Clinical Monitoring and Computing in 2016, within the field of respiration. Papers were published covering airway management, ventilation and respiratory rate monitoring, lung mechanics and gas exchange monitoring, in vitro monitoring of lung mechanics, CO 2 monitoring, and respiratory and metabolic monitoring techniques.

Previous studies have found significant differences in the likelihood of becoming an elite athlete depending on community population sizes and densities, an effect known as the place of early development, or birthplace effect. However, the results have not been consistent between sports or European countries. As both professional and voluntary clubs are vital to the talent development systems in Europe, the proximity of an athlete's place of early development to the location of talent clubs may be an important predictor of the likelihood of becoming an elite athlete. Therefore, the primary purpose of this study was to investigate the place of early development effect and the effect of proximity to talent clubs. The samples included elite youth league athletes (579 football and 311 handball) and national youth athletes (85 football and 80 handball) and a comparison group of 147 221 football and 26 290 handball youth athletes. Odds ratios showed variations in the optimal community size and density across sports. Geospatial analyses of proximity to talent clubs highlighted a trend indicating that most national and elite youth league athletes in both sports had their place of early development in their sport near a talent club. The results suggest that proximity is an important predictor in the development of expertise across sports, but future studies need to clarify if proximity is important in other countries and sports., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Arterial oxygenation is often impaired during one-lung ventilation, due to both pulmonary shunt and atelectasis. The use of low tidal volume (VT) (5 ml/kg predicted body weight) in the context of a lung-protective approach exacerbates atelectasis. This study sought to determine the combined physiologic effects of positive end-expiratory pressure and low VT during one-lung ventilation., Methods: Data from 41 patients studied during general anesthesia for thoracic surgery were collected and analyzed. Shunt fraction, high V/Q and respiratory mechanics were measured at positive end-expiratory pressure 0 cm H2O during bilateral lung ventilation and one-lung ventilation and, subsequently, during one-lung ventilation at 5 or 10 cm H2O of positive end-expiratory pressure. Shunt fraction and high V/Q were measured using variation of inspired oxygen fraction and measurement of respiratory gas concentration and arterial blood gas. The level of positive end-expiratory pressure was applied in random order and maintained for 15 min before measurements., Results: During one-lung ventilation, increasing positive end-expiratory pressure from 0 cm H2O to 5 cm H2O and 10 cm H2O resulted in a shunt fraction decrease of 5% (0 to 11) and 11% (5 to 16), respectively (P < 0.001). The PaO2/FIO2 ratio increased significantly only at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). Driving pressure decreased from 16 ± 3 cm H2O at a positive end-expiratory pressure of 0 cm H2O to 12 ± 3 cm H2O at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). The high V/Q ratio did not change., Conclusions: During low VT one-lung ventilation, high positive end-expiratory pressure levels improve pulmonary function without increasing high V/Q and reduce driving pressure.

Introduction: Advances in knowledge regarding mechanical ventilation (MV), in particular lung-protective ventilation strategies, have been shown to reduce mortality. However, the translation of these advances in knowledge into better therapeutic performance in real-life clinical settings continues to lag. High-fidelity simulation with a mannequin allows students to interact in lifelike situations; this may be a valuable addition to traditional didactic teaching. The purpose of this study is to compare computer-based and mannequin-based approaches for training residents on MV., Methods: This prospective randomized single-blind trial involved 50 residents. All participants attended the same didactic lecture on respiratory pathophysiology and were subsequently randomized into two groups: the mannequin group (n = 25) and the computer screen-based simulator group (n = 25). One week later, each underwent a training assessment using five different scenarios of acute respiratory failure of different etiologies. Later, both groups underwent further testing of patient management, using in situ high-fidelity simulation of a patient with acute respiratory distress syndrome., Results: Baseline knowledge was not significantly different between the two groups (P = 0.72). Regarding the training assessment, no significant differences were detected between the groups. In the final assessment, the scores of only the mannequin group significantly improved between the training and final session in terms of either global rating score [3.0 (2.5-4.0) vs. 2.0 (2.0-3.0), P = 0.005] or percentage of key score (82% vs. 71%, P = 0.001)., Conclusions: Mannequin-based simulation has the potential to improve skills in managing MV.

Incomplete expiration of tidal volume can lead to dynamic hyperinflation and auto-PEEP. Methods are available for assessing these, but are not appropriate for patients with respiratory muscle activity, as occurs in pressure support. Information may exist in expiratory flow and carbon dioxide measurements, which, when taken together, may help characterize dynamic hyperinflation. This paper postulates such patterns and investigates whether these can be seen systematically in data. Two variables are proposed summarizing the number of incomplete expirations quantified as a lack of return to zero flow in expiration (IncExp), and the end tidal CO 2 variability (varETCO 2 ), over 20 breaths. Using these variables, three patterns of ventilation are postulated: (a) few incomplete expirations (IncExp < 2) and small varETCO 2 ; (b) a variable number of incomplete expirations (2 ≤ IncExp ≤ 18) and large varETCO 2 ; and (c) a large number of incomplete expirations (IncExp > 18) and small varETCO 2 . IncExp and varETCO 2 were calculated from data describing respiratory flow and CO 2 signals in 11 patients mechanically ventilated at 5 levels of pressure support. Data analysis showed that the three patterns presented systematically in the data, with periods of IncExp < 2 or IncExp > 18 having significantly lower variability in end-tidal CO 2 than periods with 2 ≤ IncExp ≤ 18 (p < 0.05). It was also shown that sudden change in IncExp from either IncExp < 2 or IncExp > 18 to 2 ≤ IncExp ≤ 18 results in significant, rapid, change in the variability of end-tidal CO 2 p < 0.05. This study illustrates that systematic patterns of expiratory flow and end-tidal CO 2 are present in patients in supported mechanical ventilation, and that changes between these patterns can be identified. Further studies are required to see if these patterns characterize dynamic hyperinflation. If so, then their combination may provide a useful addition to understanding the patient at the bedside.

This paper reviews 16 papers or commentaries published in Journal of Clinical Monitoring and Computing in 2016, within the field of respiration. Papers were published covering peri- and post-operative monitoring of respiratory rate, perioperative monitoring of CO 2 , modeling of oxygen gas exchange, and techniques for respiratory monitoring.

Mathematical physiological models can be applied in medical decision support systems. To do so requires consideration of the necessary model complexity. Models that simulate changes in the individual patient are required, meaning that models should have a complexity where parameters can be uniquely identified at the bedside from clinical data and where the models adequately represent the individual patient's (patho)physiology. This paper describes the models included in a system for providing decision support for mechanical ventilation. Models of pulmonary gas exchange, respiratory mechanics, acid-base, and respiratory control are described. The parameters of these models are presented along with the necessary clinical data required for their estimation and the parameter estimation process. In doing so, the paper highlights the need for simple, minimal models for application at the bedside, directed toward well-defined clinical problems.

Background: General anaesthesia decreases pulmonary compliance and increases pulmonary shunt due to the development of atelectasis. The presence of capnoperitoneum during laparoscopic surgery may further decrease functional residual capacity, promoting an increased amount of atelectasis compared with laparotomy. The aim of this study was to evaluate the effects of different levels of positive end-expiratory pressure (PEEP) in both types of surgery and to investigate whether higher levels of PEEP should be used during laparoscopic surgery., Methods: This prospective observational study included 52 patients undergoing either laparotomy or laparoscopic surgery. Three levels of PEEP were applied in random order: (1) zero (ZEEP), (2) 5 cmH2O and (3) 10 cmH2O. Pulmonary shunt and ventilation/perfusion mismatch were assessed by the automatic lung parameter estimator system., Results: Pulmonary shunt was similar in both groups. However, in laparotomy, a PEEP of 5 cmH2O significantly decreased shunt when compared with ZEEP (12 vs 6%; P=0.001), with additional PEEP having no further effect. In laparoscopic surgery, a significant reduction in shunt (13 vs 6%; P=0.001) was obtained only at a PEEP of 10 cmH2O. Although laparoscopic surgery was associated with a lower pulmonary compliance, increasing levels of PEEP were able to ameliorate it in both groups., Conclusion: Both surgeries have similar negative effects on pulmonary shunt, while the presence of capnoperitoneum reduced only the pulmonary compliance. It appears that a more aggressive PEEP level is required to reduce shunt and to maximize compliance in case of laparoscopic surgery., (© The Author 2016. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

This paper reviews 17 papers or commentaries published in Journal of Clinical Monitoring and Computing in 2015, within the field of respiration. Papers were published covering monitoring and training of breathing, monitoring of gas exchange, hypoxemia and acid-base, and CO2 monitoring.

The primary purpose of this study was to investigate the effect of the place of early development in a sample of Danish male elite and youth handball and football players. The sample included 366 handball and football players from the elite Danish league in the season 2011-2012 and a comparison sample of youth players under the age of 12 from 2003, including 147,221 football and 26,290 handball players. Odds ratio analysis showed that both population size and density significantly affected the proportional number of youth players per community and the odds of athletes reaching an elite level in football and handball. The odds for youth player registrations in both handball and football increased in rural in contrast to urban communities. However, elite football players primarily came from communities of high density (>1000 pop./km(2)), whereas elite handball players primarily came from less densely populated communities (100 to <250 pop./km(2)). Furthermore, there seems to be a relation between representation of elite and talent clubs in different communities and the probability of becoming an elite player in both sports. The limited number of elite players in both sports from rural communities may be due to national talent development strategies that do not incorporate development support for clubs in rural areas. Additionally, the results of the study clearly suggest the need to include the youth player population to advance research findings in birthplace effect studies.

Gas exchange impairment is primarily caused by ventilation-perfusion mismatch in chronic obstructive pulmonary disease (COPD), where diffusing capacity of the lungs for carbon monoxide (DLCO) remains the clinical measure. This study investigates whether DLCO: (1) can predict respiratory impairment in COPD, that is, changes in oxygen and carbon dioxide (CO2); (2) is associated with combined risk assessment score for COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) score); and (3) is associated with blood glucose and body mass index (BMI). Fifty patients were included retrospectively. DLCO; arterial blood gas at inspired oxygen (FiO2) = 0.21; oxygen saturation (SpO2) at FiO2 = 0.21 (SpO2 (21)) and FiO2 = 0.15 (SpO2 (15)) were registered. Difference between arterial and end-tidal CO2 (ΔCO2) was calculated. COPD severity was stratified according to GOLD score. The association between DLCO, SpO2, ΔCO2, GOLD score, blood glucose, and BMI was investigated. Multiple regression showed association between DLCO and GOLD score, BMI, and glucose level (R (2) = 0.6, p < 0.0001). Linear and multiple regression showed an association between DLCO and SpO2 (21) (R (2) = 0.3, p = 0.001 and p = 0.03, respectively) without contribution from SpO2 (15) or ΔCO2. A stronger association between DLCO and GOLD score than between DLCO and SpO2 could indicate that DLCO is more descriptive of systemic deconditioning than gas exchange in COPD patients. However, further larger studies are needed. A weaker association is seen between DLCO and SpO2 (21) without contribution from SpO2 (15) and ΔCO2. This could indicate that DLCO is more descriptive of systemic deconditioning than gas exchange in COPD patients. However, further larger studies are needed., (© The Author(s) 2015.)

Purpose: This article evaluates how mathematical models of gas exchange, blood acid-base status, chemical respiratory drive, and muscle function can describe the respiratory response of spontaneously breathing patients to different levels of pressure support., Methods: The models were evaluated with data from 12 patients ventilated in pressure support ventilation. Models were tuned with clinical data (arterial blood gas measurement, ventilation, and respiratory gas fractions of O2 and CO2) to describe each patient at the clinical level of pressure support. Patients were ventilated up to 5 different pressure support levels, for 15 minutes at each level to achieve steady-state conditions. Model-simulated values of respiratory frequency (fR), arterial pH (pHa), and end-tidal CO2 (FeCO2) were compared to measured values at each pressure support level., Results: Model simulations compared well to measured data with Bland-Altman bias and limits of agreement of fR of 0.7 ± 2.2 per minute, pHa of -0.0007 ± 0.019, and FeCO2 of -0.001 ± 0.003., Conclusion: The models describe patients' fR, pHa, and FeCO2 response to changes in pressure support with low bias and narrow limits of agreement., (Copyright © 2015 Elsevier Inc. All rights reserved.)