Continuous Positive Airway Pressure Mode Research Articles

Perioperative assessment of diaphragmatic dysfunction in cardiac surgery patients and its effect on outcome; a prospective observational study

Objectives: While the assessment of the diaphragm in different clinical scenarios is quite frequent, there remains a scarcity of studies focused on assessing diaphragm dysfunction using ultrasound in cardiac surgery patients. We investigated the impact of cardiopulmonary bypass (CPB) surgery on diaphragm function and evaluated its effects on mechanical ventilation. Methodology: A prospective cohort study, on 100 consecutive adult cardiac surgery patients, was conducted at National Heart Institute. Diaphragmatic displacement (DD) or excursion and diaphragmatic thickening fraction (DTF) were measured using motion-mode ultrasound during quite normal breathing pre-operatively (the day before surgery) and post-operatively on mechanical ventilation, while the patient was fully conscious and spontaneously breathing on continuous positive airway pressure (CPAP) mode + pressure support 10 cmH2O. Then, the results were correlated to CBP time and important patient outcomes. Results: Post-operative DD was significantly less as compared to the pre-operative reading; (1.39 ± 0.42 cm vs. 2.3 ± 0.52 cm; P < 0.001), as was DTF (23% ± 10% vs. 40% ± 13%; P < 0.001). The incidence of diaphragmatic dysfunction post-cardiac surgery was 17% by the definition of DD < 1 cm, and 49% by the definition of DTF ≤ 20%. DD was positively correlated with CBP time, as well as total ventilation time and ICU stay, indicating a negative impact on overall patient outcomes. Conclusion: The results suggest that diaphragmatic dysfunction is positively correlated with CPB time, total ventilation time and ICU stay, underscoring the importance of monitoring diaphragmatic function in post-operative patients, who are difficult to wean from mechanical ventilation with apparently normal chest X-ray, particularly those with prolonged CPB time. Keywords: cardiac surgery; cardiopulmonary bypass; diaphragm dysfunction; diaphragmatic displacement; diaphragm ultrasound; mechanical ventilation. Citation: Omara ISM, Nagi HK, Mohamed KAA, Abd El Haq HH, Awdallah FF. Perioperative assessment of diaphragmatic dysfunction in cardiac surgery patients and its effect on outcome; a prospective observational study. Anaesth. pain intensive care 2024;28(5):816−823; DOI: 10.35975/apic.v28i5.2555 Received: June 28, 2024; Reviewed: September 04, 2024; Accepted: September 06, 2024

Machine learning algorithm for ventilator mode selection, pressure and volume control.

Mechanical ventilation techniques are vital for preserving individuals with a serious condition lives in the prolonged hospitalization unit. Nevertheless, an imbalance amid the hospitalized people demands and the respiratory structure could cause to inconsistencies in the patient's inhalation. To tackle this problem, this study presents an Iterative Learning PID Controller (ILC-PID), a unique current cycle feedback type controller that helps in gaining the correct pressure and volume. The paper also offers a clear and complete examination of the primarily efficient neural approach for generating optimal inhalation strategies. Moreover, machine learning-based classifiers are used to evaluate the precision and performance of the ILC-PID controller. These classifiers able to forecast and choose the perfect type for various inhalation modes, eliminating the likelihood that patients will require mechanical ventilation. In pressure control, the suggested accurate neural categorization exhibited an average accuracy rate of 88.2% in continuous positive airway pressure (CPAP) mode and 91.7% in proportional assist ventilation (PAV) mode while comparing with the other classifiers like ensemble classifier has reduced accuracy rate of 69.5% in CPAP mode and also 71.7% in PAV mode. An average accuracy of 78.9% rate in other classifiers compared to neutral network in CPAP. The neural model had an typical range of 81.6% in CPAP mode and 84.59% in PAV mode for 20 cm H2O of volume created by the neural network classifier in the volume investigation. Compared to the other classifiers, an average of 72.17% was in CPAP mode, and 77.83% was in PAV mode in volume control. Different approaches, such as decision trees, optimizable Bayes trees, naive Bayes trees, nearest neighbour trees, and an ensemble of trees, were also evaluated regarding the accuracy by confusion matrix concept, training duration, specificity, sensitivity, and F1 score.

The role of soluble guanylate cyclase stimulator riociguat in preventing the development of reperfusion lung injury after balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension

Aim. To evaluate the effect of prior administration of the soluble guanylate cyclase stimulator riociguat on the incidence and severity of reperfusion lung injury after balloon pulmonary angioplasty (BPA) in patients with inoperable form of chronic thromboembolic pulmonary hypertension (CTEPH).Materials and methods. 70 patients with inoperable CTEPH were included in the study. Patients were divided into 2 groups: Group 1 (n=41) – patients who had received PAH-specific therapy with riociguat at the time of BPA, Group 2 (n=29) – patients who underwent BPA without prior administration of riociguat. In the postoperative period all the patients underwent noninvasive artificial ventilation in continuous positive airway pressure mode in order to prevent the development of reperfusion damage of lungs.Results. Patients of group 1 received treatment with riocigiat for 6 months. At the time of BPA patients of both groups were matched for hemodynamic characteristics. In group 1, reperfusion edema above grade 1 occurred in 17.1% of patients, in group 2 – in 20.7% of patients, p=0.702. In group 1, manifestations of grade 3 reperfusion edema were found in 9.8% patients vs. 6.9% patients in group 2, (p=0.638). None of the patients in both groups had grade 4 or 5 reperfusion edema. Values of the index predicting the probability of reperfusion injury (PEPSI) were not significantly different in the group of patients who were pretreated with riociguat and in the group of patients who did not get PAH-specific therapy (p=0,588).Conclusion. There was no reliable evidence that administration of riociguat in recommended doses at least 6 months before BPA results in additional reduction in the incidence and severity of reperfusion pulmonary edema in patients with inoperable CTEPH.

Effect of CPAP therapy on the reperfusion lung injury after transluminal balloon angioplasty of the pulmonary arteries in patients with chronic thromboembolic pulmonary hypertension

Aim. To evaluate the effect of non-invasive ventilation (NIV) in CPAP (continuous positive airway pressure) mode on the development of reperfusion pulmonary edema after percutaneous balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH).Materials and methods. The study included 70 patients with CTEPH who underwent the first stage of BPA. Prevention of reperfusion edema was carried out using NIV in the CPAP mode starting from the early postoperative period in combination with oxygen and diuretic therapy (as nedeed). The presence and severity of pulmonary edema was assessed based on clinical signs and data from computed tomography or chest radiography.Results. Patients after BPA were on CPAP therapy: average pressure: 10.0±0,7 hPa. During 1st day, the average time of use was: 990±417 minutes. Prolongation of CPAP therapy >1 day occurred in 26 (37%) patients. Depending on the severity of reperfusion edema to the lungs, patients were divided into 2 groups: group 1 (grade 1, n=42) and group 2 (grade 3-4, n=12). During the observation period, there were no cases of severe reperfusion edema (grade 5), and no cases required the use of invasive ventilation or extracorporeal membrane oxygenation. No complications of CPAP therapy were recorded. The number of PA segments and ΔPFG did not differ, but the PEPSI index was higher in group 2: 41,9 [16,0; 57,9] vs 80.5 [52,5; 111,25], p=0,0146. The number of days before discharge after BPA in patients of group 2 was higher: 4.0 [3,9; 5,5] vs 7,0 [4,6; 10,0] days, p=0,013. Despite the development of reperfusion edema, before discharge the SpO2 values in group 2 were comparable to the baseline: 93,0 [89,9; 94,2] vs 93,0 [89,7; 94,4]Conclusion. Preventive use of NIV in the CPAP mode, starting from the early postoperative period, is safe and makes it possible to achieve optimal clinical results in patients even with moderate and severe lung reperfusion edema after large volumes of surgical intervention.

Lung morphology changes in patients with COVID-induced acute respiratory distress syndrome depending on the respiratory therapy options

Background. Morphologic examination of lung tissue in COVID-related acute respiratory distress syndrome is shown in publications predominantly regarding the course of disease but not the type of respiratory support. The aim of the single center study was to determine the influence of different types of respiratory therapy on morphologic findings in lung tissue of patients, who had died from COVID-19. Material and methods. The examined patients with COVID-related related acute respiratory distress syndrome (n = 30) were divided into three groups. Group 1 included those who received non-invasive lung ventilation in continuous positive airway pressure (CPAP) mode through a face mask (n = 10), group 2 consisted of patients who received oxygen therapy with a flow of 15 l/min through a rebreather mask (n = 10), and group 3 included people who underwent invasive lung ventilation through an endotracheal tube (n = 10). Results. In lung tissue of patients of group 1, we revealed prevalence of edema and hemorrhagic changes as well as discrepancy of diffuse alveolar damage (DAD) manifestations and duration of the disease. So, morphological manifestations of exudative phase of DAD were found even after 14 days of disease, and interstitial pneumonia with fibrosing alveolitis was observed only in 12.5 % of patients. The presence of dystelectasis, compensatory emphysema and thinning of the alveolar wall were typical morphological findings in the patients of group 2. Numerous hyaline membranes covered alveolar walls and led to a decrease in gas exchange area, alveolar-capillary block and were the cause of impaired lung ventilation function. Morphological signs of proliferative phase of DAD in patients of group 3 were accompanied by the development of alveolar fibrosis and secondary bacterial bronchopneumonia, especially in prolonged invasive lung ventilation. Conclusions. Low-flow oxygen therapy may lead to the progression of respiratory failure due to self-damaging of intact lung tissue. We have also revealed negative impact of invasive pulmonary ventilation on the number of bacterial complications and fibrosis stimulation. The most favorable morphologic changes were found in patients with non-invasive CPAP ventilation.

Auto-adjusted versus fixed positive airway pressure in patients with severe OSA: A large randomized controlled trial.

Continuous positive airway pressure (CPAP) in the treatment of severe obstructive sleep apnoea (OSA) can be used in fixed CPAP or auto-adjusted (APAP) mode. The aim of this prospective randomized controlled clinical study was to evaluate the 3 month-efficacy of CPAP used either in fixed CPAP or APAP mode. Eight hundred one patients with severe OSA were included in twenty-two French centres. After 7 days during which all patients were treated with APAP to determine the effective pressure level and its variability, 353 and 351 patients were respectively randomized in the fixed CPAP group and APAP group. After 3 months of treatment, 308 patients in each group were analysed. There was no difference between the two groups in terms of efficacy whatever the level of efficient pressure and pressure variability (p = 0.41). Exactly, 219 of 308 patients (71.1%) in the fixed CPAP group and 212 of 308 (68.8%) in the APAP group (p = 0.49) demonstrated residual apnoea hypopnoea index (AHI) <10/h and Epworth Score <11. Tolerance and adherence were also identical with a similar effect on quality of life and blood pressure evaluation. The two CPAP modes, fixed CPAP and APAP, were equally effective and tolerated in severe OSA patients.

Advances in Management of Respiratory Failure in Children.

Providing the right respiratory support is an essential skill, vital for anyone treating sick children. Recent advances in respiratory support include developments in both non-invasive and invasive ventilatory strategies. In non-invasive ventilation, newer modalities are being developed, in an attempt to decrease the need for invasive ventilation. This include newer techniques like Heated humidified high-flow nasal cannula (HHHFNC) and improvements in existing modes. The success of Continuous positive airway pressure (CPAP) and other non-invasive modes depend to a large extent on choosing and maintaining a suitable interface. When it comes to invasive ventilation, recent advances are focussing on increasing automation, improving patient comfort and minimising lung injury. Concepts like mechanical power are attempts at understanding the mechanisms of unintended injuries resulting from respiratory support and newer monitoring methods like transpulmonary pressure, thoracic impedance tomography are attempts at measuring potential markers of lung injury. Using the vast arrays of available ventilatory options judiciously, considering their advantages and drawbacks in every individual case will be the prime responsibility of clinicians in the future. Simultaneously, efforts have been made to identify potential drugs that can favourably modify the pathophysiology of acute respiratory distress syndrome (ARDS). Unfortunately, though eagerly awaited, most pharmaceutical agents tried in pediatric ARDS have not shown definite benefit. Pulmonary local drug and gene therapy using liquid ventilation strategies may revolutionize our future understanding and management of lung diseases.

Clinical and radiological aspects of reperfusion pulmonary edema after balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension

Aim. To study the frequency of clinical and radiological signs of reperfusion pulmonary edema and compare them with the volume of endovascular intervention after balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH).Materials and methods. The study included 50 patients with CTEPH, who underwent stage 1 PLA. To prevent severe reperfusion edema, the number of segmental arteries planned for angioplasty was taken into account, the Pulmonary Edema Predictive Scoring Index (PEPSI) was determined, and after the intervention, noninvasive ventilation was performed in the Continuous positive airway pressure (СPAP) mode for 24 hours. Clinical manifestations of reperfusion edema were assessed 1, 24, 48 and 72 hours after BPA. Radiological signs of edema were considered based on the results of multislice computed tomography (MSCT) or chest x-ray.Results. Angioplasty was performed on 97 segmental, 6 lobar pulmonary arteries, incl. by 45 (46,4%) – with occlusive lesions. The number of arteries undergoing angioplasty ranged from 1 to 7 in each patient, on average 1,9 ± 1,4, change in pulmonary flow grade (ΔPFG) – 4,3 ± 3,4, PEPSI 58,4 ± 51,0, which exceeded the recommended value of 35,5. During the 72-hour observation period, 28 (56%) patients had grade 1 edema, grade 2 reperfusion edema was observed in 15 (30%), grade 3 – in 5 (10%), grade 4 – in 2 (4%) patients. Patients with grade 2-4 edema had higher baseline mPAP (p = 0,015) and PEPSI (p = 0,046). All manifestations of reperfusion edema of 2-4 degrees were stopped due to the prolonged regimen of CPAP therapy for 3 ± 2 days. None of the patients reached grade 5 edema, and there were no deaths. Clinical manifestations of reperfusion injury were observed in 25 (50%) patients, their highest frequency was observed after 24 hoursConclusion. Balloon pulmonary angioplasty of the pulmonary arteries is a safe method for the treatment of inoperable patients with chronic thromboembolic pulmonary hypertension, provided that recommendations for the prevention of reperfusion pulmonary edema are observed. CPAP therapy can successfully prevent and stop the development of severe reperfusion injuries after BPA even when the risk index for reperfusion pulmonary edema is exceeded.

Clinical features of a young patient with COVID-19 presented with ARDS and severe thrombocytopenia

Case report of a 33-year-old male SARS-CoV-2 positive patient admitted to hospital because of hemoptysis, dyspnea, fever, oxygen saturation of 60%, hypoxemia, elevated C-reactive protein (CRP). The patient was not vaccinated and it was his first infection with the virus. The symptoms started 10 days before with headache, fever, and cough. Chest radiography on hospital admission detected diffuse interstitial pneumonia in both lungs. Initial CT (Computed Tomography) presented extensive lung involvement with bilateral wide areas of consolidation with air bronchogram, the non-consolidated area showing patchy ground glass infiltration. The patient was hospitalized in ICU (Intensive Care Unit), oxygen support was started immediately with non-invasive ventilation (NIV), CPAP (Continuous Positive Airway Pressure) mode, FiO2 (Fraction of inspired Oxygen) 100%, PEEP (Positive end-expiratory pressure) 8, and the saturation started to increase. Therapy consisted of parenteral antibiotic, low-molecular weight heparin (LMWH) in prophylactic doses, pulsed dose of corticosteroid (methylprednisolone), Remdesivir, tocilizumab (Actemra), albumin, protein-pump inhibitor, antipyretics, fluids, physical therapy. Microbiology results from sputum detected MRSA (methicillin-resistant Staphylococcus aureus) and therapy with Vancomycin was started according to recommendations. After three days of vancomycin therapy, the patient manifested profuse epistaxis and tamponade was necessary. Hemostasis result was normal, but severe thrombocytopenia was noticed in the blood count. Platelets and plasma were administered and the bleeding stopped. Vancomycin was replaced with Linezolid. In the next days of follow up, the platelets increased, and the corticosteroid dose was slowly reduced. During the treatment as the health status of the patient improved, the CPAP therapy was replaced with routine oxygen support, gradually lowering the oxygen flow until saturation of 94% was achieved at ambient air. The COVID-19 pandemic is still evolving and the medical fraternity is posed with a huge challenge. COVID-19 is primary a respiratory viral infection, but the virus can affect many organs and systems, presenting various signs, symptoms and outcomes.

Treatment of COVID-19 Acute Respiratory Distress Syndrome With a Tabletop Noninvasive Ventilation Device in a Respiratory Intermediate Care Unit.

ObjectiveTo study the outcomes of noninvasive ventilation (NIV) administered through a tabletop device for coronavirus disease 2019 acute respiratory distress syndrome in the respiratory intermediate care unit (RIMCU) at a tertiary care hospital in India.Patients and MethodsWe retrospectively studied a cohort of hospitalized patients deteriorating despite low-flow oxygen support who received protocolized management with positive airway pressure using a tabletop NIV device in the RIMCU as a step-up rescue therapy from July 30, 2020 to November 14, 2020. Treatment was commenced on the continuous positive airway pressure mode up to a pressure of 10 cm of H2O, and if required, inspiratory pressures were added using the bilevel positive air pressure mode. Success was defined as weaning from NIV and stepping down to the ward, and failure was defined as escalation to the intensive care unit, the need for intubation, or death.ResultsIn total, 246 patients were treated in the RIMCU during the study period. Of these, 168 received respiratory support via a tabletop NIV device as a step-up rescue therapy. Their mean age was 54 years, and 83% were men. Diabetes mellitus (78%) and hypertension (44%) were the commonest comorbidities. Treatment was successful with tabletop NIV in 77% (129/168) of the patients; of them, 41% (69/168) received treatment with continuous positive airway pressure alone and 36% (60/168) received additional increased inspiratory pressure via the bilevel positive air pressure mode.ConclusionRespiratory support using the tabletop NIV device was an effective and economical treatment for coronavirus disease 2019 acute respiratory distress syndrome. Further studies are required to assess the appropriate time of initiation for maximal benefits and judicious utilization of resources.

Efficacy of high-flow nasal cannula therapy in bedridden patients.

A growing number of studies have demonstrated the efficacy of high-flow nasal cannula therapy (HFNC) for treating children with acute respiratory distress. However, it remains unknown whether HFNC is effective in bedridden patients with acute respiratory distress. We retrospectively reviewed the medical records of bedridden patients with acute respiratory distress who were treated with HFNC using a home ventilator in continuous positive airway pressure mode at our center between March 2014 and August 2016. We assessed heart rate, respiratory rate, oxygen saturation measured using a pulse oximeter, the partial pressure of venous carbon dioxide, or the transcutaneous partial pressure of carbon dioxide, and symptoms of respiratory distress before and after the initiation of HFNC. During the 2-year-study period, 25 patients were treated with HFNC. The patients' mean heart rate, respiratory rate, oxygen saturation measured using a pulse oximeter, and pressure of venous carbon dioxide/the transcutaneous partial pressure of carbon dioxide values improved significantly (P < 0.05). Symptoms of respiratory distress were considerably ameliorated at 1-3 h after the HFNC initiation, except in two patients. In these two patients, the HFNC was replaced with non-invasive positive pressure ventilation. Non-invasive positive pressure was also required at 16 to 168 h after the initiation of HFNC in five of the 28 episodes in which the patient was initially responsive to HFNC, as the patients' respiratory symptoms gradually deteriorated. Performing HFNC with a home ventilator in continuous positive airway pressure mode is effective at treating bedridden patients with acute respiratory distress. However, it is essential that the HFNC can be switched to non-invasive positive pressure if needed.

Is bilevel PAP more effective than CPAP in treating hypercapnic obese patients with COPD and severe OSA?

Commentary on Zheng Y, Yee BJ, Wong K, Grunstein R, Piper A. A pilot randomized trial comparing CPAP versus bilevel PAP spontaneous mode in the treatment of hypoventilation disorder in patients with obesity and obstructive airway disease. J Clin Sleep Med. 20XX;XX(XX):XXX-XXX. doi:10.5664/jcsm.9506.

A pilot randomized trial comparing CPAP vs bilevel PAP spontaneous mode in the treatment of hypoventilation disorder in patients with obesity and obstructive airway disease.

Both obesity and airways disease can lead to chronic hypercapnic respiratory failure, which can be managed with positive airway pressure (PAP) therapy. The efficacy of PAP has been studied in obesity hypoventilation syndrome as well as in chronic hypercapnic chronic obstructive pulmonary disease patients, but not in patients where both obesity and airway obstruction coexist. This pilot study aims to compare the efficacy of continuous positive airway pressure vs bilevel positive airway pressure spontaneous mode in the treatment of hypoventilation disorder with obesity and obstructive airways disease. We sequentially screened PAP-naïve patients with stable chronic hypercapnic respiratory failure (PaCO2 > 45 mm Hg), obesity (body mass index > 30 kg/m2), and obstructive airways disease. Participants were randomized to continuous positive airway pressure or bilevel positive airway pressure spontaneous mode treatment for 3 months. Participants were blinded to their PAP allocation. Change in awake PaCO2 was the primary endpoint. Secondary endpoints included change in lung function, daytime sleepiness, sleep quality, quality of life, PAP adherence, and neurocognitive function. A total of 32 individuals were randomized (mean ± SD: age 61 ± 11 years, body mass index 43 ± 7 kg/m2, PaCO2 54 ± 7 mm Hg, forced expiratory volume in 1 second 1.4 ± 0.6L, apnea-hypopnea index 59 ± 35 events/h). Sixteen participants in each PAP group were analyzed. Bilevel positive airway pressure yielded a greater improvement in PaCO2 compared to continuous positive airway pressure (9.4 mm Hg, 95% confidence interval, 4.3-15 mm Hg). There were no significant differences in PAP adherence, sleepiness, sleep quality, or neurocognitive function between the two therapies. Although both PAP modalities improved hypercapnic respiratory failure in this group of individuals, bilevel positive airway pressure spontaneous mode showed greater efficacy in reducing PaCO2. Registry: Australian New Zealand Clinical Trials Registry; Name: Nocturnal ventilatory support in obesity hypoventilation syndrome; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12605000096651; Identifier: ACTRN12605000096651. Zheng Y, Yee BJ, Wong K, Grunstein R, Piper A. A pilot randomized trial comparing CPAP vs bilevel PAP spontaneous mode in the treatment of hypoventilation disorder in patients with obesity and obstructive airway disease. J Clin Sleep Med. 2022;18(1):99-107.

Comparison of different methods of obtaining the rapid shallow breathing index

ObjectiveTo compare the Rapid Shallow Breathing Index (RSBI) obtained by the ventilometer and from mechanical ventilation parameters. MethodsRandomized crossover trial, including 33 intubated patients, on mechanical ventilation for at least 24 hours, undergoing spontaneous breathing test. Patients were submitted to the measurement of RSBI by four methods: disconnected from the ventilator through the ventilometer; in Pressure Support Ventilation (PSV) mode at a pressure of 7.ßcm H2O; in Continuous Positive Airway Pressure (CPAP) mode at a pressure of 5.ßcmH2O with flow trigger; in CPAP mode at a pressure of 5.ßcmH2O with pressure trigger. ResultsNo significant difference was detected between the RSBI obtained by the ventilometer and in the CPAP mode with flow and pressure triggers, however, in the PSV mode, the values were lower than in the other measurements (p.ß<.ß0.001). By selecting patients from the sample with higher RSBI (... 80 cycles.min-1.L-1), the value of the index obtained by the ventilometer was higher than that obtained in the three options of ventilation methods. ConclusionThe RSBI obtained in the CPAP mode at a pressure of 5.ßcmH2O, in both triggers types, did not differ from that measured by the ventilometer; it is, therefore, an alternative when obtaining it from mechanical ventilation parameters is necessary. However, in the presence of borderline values, the RSBI measured by ventilometer is recommended, as in this method the values are significantly higher than in the three ventilation modalities investigated.

Impact of continuous positive airway pressure mode on adherence to treatment in obstructive sleep apnea patients awaiting bariatric surgery.

Obstructive sleep apnea is prevalent in the bariatric population, and is associated with various complications. Despite increasing popularity, automatic positive airway pressure has not yet been studied in this population. The objective was to compare treatment adherence between automatic positive airway pressure and fixed positive airway pressure (continuous positive airway pressure) in obstructive sleep apnea patients awaiting bariatric surgery. This randomized controlled trial involved obese patients newly diagnosed with severe obstructive sleep apnea and awaiting bariatric surgery. The primary outcome was the difference in adherence between automatic positive airway pressure and continuous positive airway pressure pre-operatively. Secondary outcomes included positive airway pressure efficacy, adherence at 1 month, adverse effects, quality of life and peri-operative complications. Analyses were conducted using a modified intention-to-treat methodology. Fifty patients were randomized. Baseline characteristics and duration of positive airway pressure therapy were comparable between groups. At the time of surgery, the percentage of overall nights positive airway pressure used was 96.9% [95% confidence interval: 93.5-100] and 86.0% [95% confidence interval: 66.9-100] in the automatic positive airway pressure and continuous positive airway pressure groups, respectively (p=.047). Average use was 6.3hr per night [95% confidence interval: 5.1-7.2] and 5.9hr per night [95% confidence interval: 3.0-8.8], with a difference of 0.4hr favouring automatic positive airway pressure (p=.75). Nightly use≥4 hr per night was 86.4% and 74.0% in the automatic positive airway pressure and fixed continuous positive airway pressure groups, respectively (p=.22). There were no statistically significant differences regarding adherence at 1 month, efficacy parameters, adverse effects, quality of life and peri-operative complications. With no difference on the safety profile and efficiency parameters, treatment adherence is not improved with automatic positive airway pressure compared with fixed continuous positive airway pressure in obstructive sleep apnea patients awaiting bariatric surgery.

Role of capnography in detecting hypercapnic events during weaning from mechanical ventilation

Background End-tidal carbon dioxide (ETCO2) measurement is more applied in clinical practice, as it is a noninvasive tool that helps to evaluate the ventilatory status of the patient. The aim of the present study was to investigate the relationship between ETCO2 and arterial partial pressure of CO2 (PaCO2) measurements and to estimate the role of capnography during weaning off mechanical ventilation. Patients and methods A prospective cross-sectional study was conducted on 60 adult critically ill patients with respiratory failure, comprising 47 males and 13 females. They were put on mechanical ventilation, and after fulfilling criteria of weaning, they were kept on continuous positive airway pressure (CPAP) mode for 1 h. ETCO2, PaCO2, and gradient were measured before and after weaning. Results Mean difference between PaCO2 and ETCO2 before weaning was 8.3 and after one hour on CPAP was 5.1. There was a highly statistically significant positive correlation between ETCO2 and PaCO2 before weaning and after 1 h on CPAP. Bland-Altman comparison between ETCO2 and PaCO2 before weaning and after 1 h on CPAP revealed limits of agreement were 1.941 to 14.826 and −4.134 to 14.367, respectively. Conclusion ETCO2 measurement gives a proper estimation of PaCO2 in patients on mechanical ventilation. ETCO2 decreases the need for repeated invasive arterial blood gas samples.

Mechanical ventilation of patients in helicopter emergency medical service transport: an international survey

BackgroundMechanical ventilation in helicopter emergency medical service (HEMS) environments is a procedure which carries a significant risk of complications. Limited data on the quality and performance of mechanical ventilation in HEMS are available in the literature.MethodWe conducted an international survey to evaluate mechanical ventilation infrastructure in HEMS and collect data of transported ventilated patients. From June 20–22, 2019, the participating HEMS bases were asked to provide data via a web-based platform. Vital parameters and ventilation settings of the patients at first patient contact and at handover were compared using non-parametric statistical tests.ResultsOut of 215 invited HEMS bases, 53 responded. Respondents were from Germany, Denmark, United Kingdom, Luxembourg, Austria and Switzerland. Of the HEMS bases, all teams were physician staffed, mainly anesthesiologists (79%), the majority were board certified (92.5%) and trained in intensive care medicine (89%) and had a median (range) experience in HEMS of 9 (0–25) years. HEMS may provide a high level of expertise in mechanical ventilation whereas the majority of ventilators are able to provide pressure controlled ventilation and continuous positive airway pressure modes (77%). Data of 30 ventilated patients with a median (range) age of 54 (21–100) years and 53% male gender were analyzed. Of these, 24 were primary missions and 6 interfacility transports. At handover, oxygen saturation (p < 0.01) and positive end-expiratory pressure (p = 0.04) of the patients were significantly higher compared to first patient contact.ConclusionIn this survey, the management of ventilated HEMS-patients was not associated with ventilation related serious adverse events. Patient conditions, training of medical crew and different technical and environmental resources are likely to influence management. Further studies are necessary to assess safety and process quality of mechanical ventilation in HEMS.Trial registrationThe survey was prospectively registered at Research Registry (researchregistry2925).

Comparison of non-invasive CPAP with mask use in carbon monoxide poisoning

BackgroundCarbon monoxide (CO) is one of the major causes of poisoning worldwide. We aimed to investigate the efficacy of the continuous positive airway pressure (CPAP) use in CO poisoning. MethodsAfter CO poisoning, one group of patients was treated with a non-rebreather mask (NRB) and another group using the CPAP mode of mechanical ventilation (CPAP). All patients received at least 90 minute treatment. The carboxyhemoglobin saturation (SpCO) levels of all patients were measured from the fingertips with a portable CO-oximeter at 0, 30, 60 and 90 min. The rates of changes in the serially measured SpCO values were obtained using the Wilcoxon signed-rank test. ResultsA total of 45 patients (24 in NRB and 21 in CPAP group) completed the study. The median initial SpCO levels were 24% (21−33) in NRB group, 25% (21−32) in CPAP group, with no statistically significant difference (p 0.323). At the 30th, 60th, and 90th minutes of treatment, significantly lower values were obtained from CPAP than NRB (p < 0.001). The COHb half-life was decreased significantly by CPAP [105(70–190) vs 45(30−120), p < 0.001]. In CPAP group, the fastest decline in the SpCO level was observed for the interval of 0–30 min [Median difference: 8(3–14), p < 0.001]. ConclusionsCPAP lowered the amount of CO in the blood faster than the mask; therefore, it may be effective in the treatment of CO poisoning.

Success of bubble continuous positive airway pressure in preterm neonates admitted with respiratory distress syndrome at tertiary care center

Background: Application of continuous positive airway pressure (CPAP) in neonate with respiratory distress is associated with reduction of respiratory failure, complications, and mortality. Bubble CPAP (B-CPAP) is a most popular CPAP mode, but studies on B-CPAP as respiratory support for neonates are few. Therefore, the present study was conducted to assess the effectiveness of B-CPAP on immediate outcome of preterm infants of gestational age 28–36 weeks with respiratory distress syndrome (RDS) and to identify the risk factors associated with its failure. Materials and Methods: This longitudinal study was conducted in neonates admitted in the newborn unit with respiratory distress with Downe's score 4–6, SPO2 < 85% even with supplemental oxygen during a period from August 1, 2019 to July 31, 2020. Investigations to diagnose the cause of respiratory distress were done including radiograph of the chest in all cases. Results: Out of total 330 neonates, 245 babies weaned from CPAP ventilation and discharged while 85 babies succumbed to the illness. Mortality was high in male babies, weighing <1.5 kg and babies with septicemia. At day 0 of administration of B-CPAP, 25.75% had Downes score 4, 33.03% were in score 5, and 41.21% were in score 6. All parameters such as cyanosis, grunting, tachypnea, chest indrawing, and air entry improved with B-CPAP administration. The various causes of respiratory distress were asphyxia, RDS, apnea of prematurity, meconium aspiration syndrome (MAS), and bronchopneumonia sepsis. Out of this, 22 babies with RDS and all babies with MAS and sepsis had significant radiological findings. Conclusion: We concluded that, this form of therapy should be adopted even by the smaller hospitals to improve the survival of neonates with respiratory distress.

Ventilación mecánica no invasiva en pacientes con traumatismo de tórax

Mechanical ventilation in patients with chest injury becomes a challenge due to physiological changes. Currently, chest injuries account for 10-15% of all traumas, and are responsible for 17-25% of all deaths caused by trauma. However, there is no clinical evidence to make recommendations for the use of any of the ventilation modes. The objective of this study is to demonstrate that non-invasive mechanical ventilation (NIMV) corrects hypoxaemia in chest trauma patients. Materials and methodsProspective descriptive, observational and analytical study was conducted on 19 patients with chest trauma managed with NIMV in the continuous positive airway pressure (CPAP) mode. The age of the patients was between 18 and 67 years. For those patients with criteria for NIMV, the protocol implemented was 4hours of NIMV in CPAP mode with full mask. The parameters included: A pressure support variable plus a positive end-expiratory pressure of 10cm H2O, and FiO2 at 50% for 4h of venturi mask at 50%. Arterial blood samples were taken one hour after NIMV withdrawal. Failure was defined if continued with venturi, returned to NIMV, or went on to invasive mechanical ventilation. ResultsThe study included 89.5% males, and all (100%) of the patients had a mean Revised Trauma Score of less than 11 on admission to the emergency department, as well as a mean Injury Severity Score of 19, a mean Thorax Trauma Severity Score of 10, as well as a mean base excess −2.0. The mean time of NIMV was 3.2 days. An improvement of PO2 and PaO2/FiO2 index (PAFI) was observed in relation to the use of NIMV in CPAP mode, as well as a relationship with the classification of thoracic trauma (TTSS), and the time of NIMV. With this study, it can be concluded that NIMV in patients with chest trauma reduces intubation time and reduces mortality, as well as improving hypoxaemia in this group of patients.