Influence of Fractional Inspired Oxygen Tension on Lung Perfusion Distribution, Regional Ventilation, and Lung Volume during Mechanical Ventilation of Supine Healthy Swine.

BACKGROUND: Lower fractional inspired oxygen tension (Fio2) during general anesthesia can reduce lung atelectasis. The objectives are to evaluate the effect of two Fio2 (0.4 and 1) during low positive end-expiratory pressure (PEEP) ventilation over lung perfusion distribution, volume, and regional ventilation. These variables were evaluated at two PEEP levels and unilateral lung atelectasis. METHODS: In this exploratory study, 10 healthy female piglets (32.3 ± 3.4 kg) underwent mechanical ventilation in two atelectasis models: (1) bilateral gravitational atelectasis (n = 6), induced by changes in PEEP and Fio2 in three combinations: high PEEP with low Fio2 (Fio2 = 0.4), zero PEEP (PEEP0) with low Fio2 (Fio2 = 0.4), and PEEP0 with high Fio2 (Fio2 = 1); and (2) unilateral atelectasis (n = 6), induced by left bronchial occlusion, with the left lung aerated (Fio2 = 0.21) and low aerated (Fio2 = 1; n = 5 for this step). Measurements were conducted after 10 min in each step, encompassing assessment of respiratory mechanics, oxygenation, and hemodynamics; lung ventilation and perfusion by electrical impedance tomography; and lung aeration and perfusion by computed tomography. RESULTS: During bilateral gravitational atelectasis, PEEP reduction increased atelectasis in dorsal regions, decreased respiratory compliance, and distributed lung ventilation to ventral regions with a parallel shift of perfusion to the same areas. With PEEP0, there were no differences between low and high Fio2 in respiratory compliance (23.9 ± 6.5 ml/cm H2O vs. 21.9 ± 5.0; P = 0.441), regional ventilation, and regional perfusion, despite higher lung collapse (18.6 ± 7.6% vs. 32.7 ± 14.5%; P = 0.045) with high Fio2. During unilateral lung atelectasis, the deaerated lung had a lower shunt (19.3 ± 3.6% vs. 25.3 ± 5.5%; P = 0.045) and lower computed tomography perfusion to the left lung (8.8 ± 1.8% vs. 23.8 ± 7.1%; P = 0.007). CONCLUSIONS: PEEP0 with low Fio2, compared with high Fio2, did not produce significant changes in respiratory system compliance, regional lung ventilation, and perfusion despite significantly lower lung collapse. After left bronchial occlusion, the shrinkage of the parenchyma with Fio2 = 1 enhanced hypoxic pulmonary vasoconstriction, reducing intrapulmonary shunt and perfusion of the nonventilated areas.

[Efficacy of bronchoalveolar lavage combined with prone positioning in children with Mycoplasma pneumoniae pneumonia and atelectasis: a prospective randomized controlled study]. / æ”¯æ°”ç®¡è‚ºæ³¡çŒæ´—è”åˆä¿¯å§ä½æ²»ç–—å„¿ç«¥è‚ºç‚Žæ”¯åŽŸä½“è‚ºç‚Žä¼´è‚ºä¸å¼ ç–—æ•ˆçš„å‰çž»æ€§éšæœºå¯¹ç §ç ”ç©¶.

OBJECTIVES: To study the efficacy of bronchoalveolar lavage (BAL) combined with prone positioning in children with Mycoplasma pneumoniae pneumonia (MPP) and atelectasis and its effect on pulmonary function. METHODS: A prospective study was conducted on 94 children with MPP and atelectasis who were hospitalized in Ordos Central Hospital of Inner Mongolia from November 2020 to May 2023. The children were randomly divided into a treatment group and a control group, with 47 children in each group. The children in the treatment group were given conventional treatment, BAL, and prone positioning, and those in the control group were given conventional treatment and BAL. The two groups were compared in terms of fever, pulmonary signs, length of hospital stay, lung recruitment, and improvement in pulmonary function. RESULTS: Compared with the control group, the treatment group had significantly shorter time to improvement in pulmonary signs and length of hospital stay and a significantly higher rate of lung recruitment on day 7 of hospitalization, on the day of discharge, and at 1 week after discharge (P<0.05). Compared with the control group, the treatment group had significantly higher levels of forced vital capacity (FVC) as a percentage of the predicted value, forced expiratory volume (FEV) in 1 second as a percentage of the predicted value, ratio of FEV in 1 second to FVC, forced expiratory flow at 50% of FVC as a percentage of the predicted value, forced expiratory flow at 75% of FVC as a percentage of the predicted value, and maximal mid-expiratory flow as a percentage of the predicted value on the day of discharge and at 1 week after discharge (P<0.05). There was no significant difference in the time for body temperature to return to normal between the two groups (P>0.05). CONCLUSIONS: In the treatment of children with MPP and atelectasis, BAL combined with prone positioning can help to shorten the time to improvement in pulmonary signs and the length of hospital stay and promote lung recruitment and improvement in pulmonary function.

Bronchoscopic treatment of pediatric atelectasis: A modified segmental insufflation-surfactant instillation technique.

BACKGROUND: Atelectasis is a condition characterized by the collapse and nonaeration of lung regions and is considered a manifestation of an underlying disease process. The goal of atelectasis treatment is the restoration of volume loss. In the range of different treatment options, chest physiotherapy is often used as a first-line approach, and some cases require bronchoscopic interventions. METHODS: In this case series, we describe a modified bronchoscopic treatment procedure using pressure-controlled bronchoscopic segmental insufflation with surfactant application. RESULTS: The proposed approach resulted in significant improvement of lung volume across a range of patients including massive lobar, atypical rounded atelectasis in previously healthy patients, and in a particularly challenging case involving an infant suffering from spinal muscular atrophy type I. CONCLUSION: The modified segmental insufflation-surfactant instillation technique offers a safe and promising easily implementable treatment of persistent atelectasis caused by different underlying disease processes with positive long-term outcomes.

[Recurrent atelectasis in an infant : about one case of false-negative newborn screening for cystic fibrosis]. / Atélectasie récidivante chez un nourrisson : à propos d'un cas de faux-négatif du dépistage néonatal pour la mucoviscidose.

In infants as well as in older children, persistent or recurrent atelectasis remains a classic indication for sweat testing, even if neonatal screening for cystic fibrosis has been considered normal. Atelectasis is a common complication of cystic fibrosis. Yet, it has rarely been reported in infants. In cystic fibrosis, chronic atelectasis worsens the prognosis, especially when involving a lower lobe. Therefore, early and effective intervention is required. Antibiotic therapy, intensive chest physiotherapy together with inhaled mucolytics often allow to relieve bronchial obstruction but bronchoscopy with local aspiration and Dornase alpha instillation is sometimes necessary. In a two-month-old infant, we describe here the first reported case of false-negative cystic fibrosis newborn screening in Belgium.

Chez le nourrisson comme chez l'enfant plus âgé, une atélectasie persistante ou récidivante reste une indication classique de test à la sueur, même si le dépistage néonatal de la mucoviscidose a été considéré comme normal. Rarement rapportées chez le nourrisson, les atélectasies sont une complication commune de la mucoviscidose. Dans cette affection, l'atélectasie chronique d'un territoire péjore le pronostic, en particulier si elle concerne un lobe inférieur. Une intervention précoce et efficace est donc requise. Antibiothérapie, kinésithérapie respiratoire intensive et recours aux fluidifiants par voie de nébulisation suffisent souvent à lever l'obstruction bronchique, mais une endoscopie avec aspiration locale et instillation de dornase alpha est parfois nécessaire. Chez un nourrisson de 2 mois, nous rapportons ici le premier cas de faux-négatif du programme belge de dépistage néonatal de la mucoviscidose.

[Risk factors for pulmonary atelectasis in adults with tracheobronchial tuberculosis].

Objective: To investigate the risk factors for pulmonary atelectasis in adults with tracheobronchial tuberculosis(TBTB). Methods: Clinical data of adult patients (≥18 years old) with TBTB from February 2018 to December 2021 in Public Health Clinical Center of Chengdu were retrospectively analyzed. A total of 258 patients were included, with a male to female ratio of 1∶1.43. The median age was 31(24, 48) years. Clinical data including clinical characteristics, previous misdiagnoses/missed diagnoses before admission, pulmonary atelectasis, the time from symptom onset to atelectasis and bronchoscopy, bronchoscopy and interventional treatment were collected according to the inclusion and exclusion criteria. Patients were divided into two groups according to whether they had pulmonary atelectasis. Differences between the two groups were compared. Binary logistic regression was used to analyze the risk factors for pulmonary atelectasis. Results: The prevalence of pulmonary atelectasis was 14.7%, which was most common in the left upper lobe (26.3%). The median time from symptom onset to atelectasis was 130.50(29.75,358.50)d, and the median time from atelectasis to bronchoscopy was 5(3,7)d. The median age, the proportion of misdiagnosis of TBTB before admission, and the time from symptom onset to bronchoscopy in the atelectasis group were higher than those without atelectasis, and the proportion of receiving bronchoscopy examination and interventional therapy previously, and the proportion of pulmonary cavities were lower than those without atelectasis (all P<0.05). The proportions of cicatrices stricture type and lumen occlusion type in the atelectasis group were higher than those without atelectasis, while the proportions of inflammatory infiltration type and ulceration necrosis type were lower than those without atelectasis (all P<0.05). Older age (OR=1.036, 95%CI: 1.012-1.061), previous misdiagnosis(OR=2.759, 95%CI: 1.100-6.922), longer time from symptom onset to bronchoscopy examination (OR=1.002, 95%CI: 1.000-1.005) and cicatrices stricture type (OR=2.989, 95%CI: 1.279-6.985) were independent risk factors for pulmonary atelectasis in adults with TBTB (all P<0.05). Of the patients with atelectasis who underwent bronchoscopy interventional therapy, 86.7% had lung reexpansion or partial reexpansion. Conclusions: The prevalence of pulmonary atelectasis is 14.7% in adult patients with TBTB. The most common site of atelectasis is left upper lobe. The TBTB type of lumen occlusion is complicated by pulmonary atelectasis in 100% of cases. Being older, misdiagnosed as other diseases, longer time from onset of symptoms to bronchoscopy examination, and being the cicatrices stricture type are factors for developing pulmonary atelectasis. Early diagnosis and treatment are needed to reduce the incidence of pulmonary atelectasis and increase the rate of pulmonary reexpansion.

Effect of Active Physiotherapy With Positive Airway Pressure on Pulmonary Atelectasis After Cardiac Surgery: A Randomized Controlled Study.

OBJECTIVES: The authors investigated the effect of active work with positive airway pressure (PAP) in addition to chest physiotherapy (CP) on pulmonary atelectasis (PA) in patients undergoing cardiac surgery with cardiopulmonary bypass. DESIGN: A randomized controlled study. SETTING: At a single-center tertiary hospital. PARTICIPANTS: Eighty adult patients undergoing cardiac surgery (coronary artery bypass grafting, valve surgery, or both), and presenting with PA after tracheal extubation on postoperative days 1 or 2, were randomized from November 2014 to September 2016. INTERVENTION: Three days of CP, twice daily, associated with active work with PAP effect (intervention group) versus CP alone (control group). Pulmonary atelectasis was assessed by using the radiologic atelectasis score (RAS) measured from daily chest x-rays. All radiographs were reviewed blindly. MEASUREMENTS AND MAIN RESULTS: Among included patients, 79 (99%) completed the trial. The primary outcome was mean RAS on day 2 after inclusion. It was significantly lower in the intervention group (mean difference and 95% CI: -1.1 [-1.6 to -0.6], p < 0.001). The secondary outcomes were the sniff nasal inspiratory pressure measured before and after CP and clinical variables. Sniff nasal inspiratory pressure was significantly higher in the intervention group on day 2 (7.7 [3.0-12.5] cmH2O, p = 0.002). The respiratory rate was lower in the intervention group (-3.2 [95% CI -4.8 to -1.6] breaths/min, p < 0.001) on day 2. No differences were found between the 2 groups for percutaneous oxygen saturation/oxygen requirement ratio, heart rate, pain, and dyspnea scores. CONCLUSIONS: Active work with the PAP effect, combined with CP, significantly decreased the RAS of patients undergoing cardiac surgery after 2 days of CP, with no differences observed in clinically relevant parameters.

Variable ventilation versus stepwise lung recruitment manoeuvres for lung recruitment: A comparative study in an experimental model of atelectasis.

BACKGROUND: Variable ventilation recruits alveoli in atelectatic lungs, but it is unknown how it compares with conventional recruitment manoeuvres. OBJECTIVES: To test whether mechanical ventilation with variable tidal volumes and conventional recruitment manoeuvres have comparable effects on lung function. DESIGN: Randomised crossover study. SETTING: University hospital research facility. ANIMALS: Eleven juvenile mechanically ventilated pigs with atelectasis created by saline lung lavage. INTERVENTIONS: Lung recruitment was performed using two strategies, both with an individualised optimal positive-end expiratory pressure (PEEP) associated with the best respiratory system elastance during a decremental PEEP trial: conventional recruitment manoeuvres (stepwise increase of PEEP) in pressure-controlled mode) followed by 50 min of volume-controlled ventilation (VCV) with constant tidal volume, and variable ventilation, consisting of 50 min of VCV with random variation in tidal volume. MAIN OUTCOME MEASURES: Before and 50 min after each recruitment manoeuvre strategy, lung aeration was assessed by computed tomography, and relative lung perfusion and ventilation (0% = dorsal, 100% = ventral) were determined by electrical impedance tomography. RESULTS: After 50 min, variable ventilation and stepwise recruitment manoeuvres decreased the relative mass of poorly and nonaerated lung tissue (percent lung mass: 35.3 ±â€Š6.2 versus 34.2 ±â€Š6.6, P  = 0.303); reduced poorly aerated lung mass compared with baseline (-3.5 ±â€Š4.0%, P  = 0.016, and -5.2 ±â€Š2.8%, P  < 0.001, respectively), and reduced nonaerated lung mass compared with baseline (-7.2 ±â€Š2.5%, P  < 0.001; and -4.7 ±â€Š2.8%, P  < 0.001 respectively), while the distribution of relative perfusion was barely affected (variable ventilation: -0.8 ±â€Š1.1%, P  = 0.044; stepwise recruitment manoeuvres: -0.4 ±â€Š0.9%, P  = 0.167). Compared with baseline, variable ventilation and stepwise recruitment manoeuvres increased Pa O 2 (172 ±â€Š85mmHg, P  = 0.001; and 213 ±â€Š73 mmHg, P  < 0.001, respectively), reduced Pa CO 2 (-9.6 ±â€Š8.1 mmHg, P  = 0.003; and -6.7 ±â€Š4.6 mmHg, P  < 0.001, respectively), and decreased elastance (-11.4 ±â€Š6.3 cmH 2 O, P  < 0.001; and -14.1 ±â€Š3.3 cmH 2 O, P  < 0.001, respectively). Mean arterial pressure decreased during stepwise recruitment manoeuvres (-24 ±â€Š8 mmHg, P  = 0.006), but not variable ventilation. CONCLUSION: In this model of lung atelectasis, variable ventilation and stepwise recruitment manoeuvres effectively recruited lungs, but only variable ventilation did not adversely affect haemodynamics. TRIAL REGISTRATION: This study was registered and approved by Landesdirektion Dresden, Germany (DD24-5131/354/64).

Quantification of changes in lung aeration associated with physiotherapy using lung ultrasound in mechanically ventilated patients: a prospective cohort study.

BACKGROUND: Lung ultrasound (LUS) is a novel and emerging tool for physiotherapists in ICU and may provide a way of monitoring lung aeration change in response to respiratory physiotherapy treatment during a patient's ICU stay. OBJECTIVE: To measure change in the LUS score associated with a respiratory physiotherapy treatment; to determine whether change in LUS score correlates with other physiological measures. DESIGN AND SETTING: A single-centre prospective cohort study was undertaken in a tertiary teaching hospital in Sydney, Australia. PATIENTS: Adult mechanically ventilated patients in ICU with suspicion of atelectasis. MEASUREMENTS: Primary outcome: pre-post difference in LUS score. SECONDARY OUTCOMES: PaO2/FiO2 (PF) ratio, tidal volume (VT), lung auscultation score, driving pressure (DP) and the modified radiological atelectasis score (mRAS) on CXR. RESULTS: 43 patients were included. There was a mean improvement in total LUS score after physiotherapy treatment of - 2.9 (95%CI -4.4, -1.4), and a mean improvement in LUS of the right and left lungs of - 1.6 (-2.5, -0.7) and - 1.3 (-2.5, -0.1) respectively. There was a mean improvement in PF ratio, VT and auscultation score of 10.4 (-11.89, 32.7), 19 (-7.4, 44.5) and - 1.8 (-2.6, -1.0) respectively. There was no improvement in mRAS or DP. There was a weak correlation between change in LUS score compared with change in mRAS score. LIMITATIONS: Limitations included the prospective cohort single site design and the small sample size. CONCLUSIONS: The LUS score can be used to detect changes in lung aeration associated with respiratory physiotherapy treatment for acute lobar atelectasis in mechanically ventilated patients. Australian and New Zealand Clinical Trials Registry Number: ACTRN12619000783123. CONTRIBUTION OF THE PAPER.

Comparison of the efficacy of two alveolar recruitment manoeuvres in improving the lung mechanics and the degree of atelectasis in anaesthetized healthy sheep.

The aim of the present study was to evaluate whether the application of two types of alveolar recruitment manoeuvres (ARMs) followed by a positive end-expiratory pressure (PEEP) improved lung mechanics and the degree of atelectasis caused by general anaesthesia. Twenty-one female Merino sheep were divided into three groups: sustained inflation ARM (ARMsust), stepwise ARM (AMRstep), and control (without ARM). Sheep received detomidine-morphine for premedication, propofol for induction, and isoflurane during general anaesthesia in a volume-controlled mode with 100% oxygen during the first 15 min of anaesthesia and 40% the rest of the study. The right jugular vein and metacarpal artery were catheterised for mixed venous and arterial blood sample collection, respectively. The quasistatic compliance (Cqst), oxygenation parameters, and shunt fraction (Qs/Qt) were monitored before ARM application (TpreARM), and at 10 (T10) and 60 min (T60) after ARM application. A pulmonary histopathological study was conducted on five animals from each group. A significant increase in Cqst was observed in both ARM groups at T10 compared to TpreARM (ARMsust: P = 0.001; ARMstep: P = 0.002), although only the ARMsust group showed significant differences compared to the control group. The ARMstep group presented a significant improvement in oxygenation parameters and Qs/Qt fraction (T10: 4.84 (3.26-16.48)%, P = 0.048; T60: 4.40 (4.31-14.16)%, P = 0.004) compared with TpreARM (21.48 (20.61-28.32)%). The ARMstep group had the highest percentage of alveolar area and the most homogeneous values. In conclusion, the application of a stepwise ARM followed by PEEP improved atelectasis caused by isoflurane anaesthesia in healthy sheep.

Effect of positioning and expiratory rib-cage compression on atelectasis in a patient who required prolonged mechanical ventilation: a case report.

BACKGROUND: Pulmonary complications can be caused by intraoperative mechanical ventilation. In particular, prolonged mechanical ventilation is associated with a high mortality rate, a risk of pulmonary complications, prolonged hospitalization, and an unfavorable discharge destination. Pre- and postoperative rehabilitation are important for the resolution of pulmonary complications in acute cases. However, there has been a lack of studies on interventions for pulmonary rehabilitation of patients with chronic pulmonary complications caused by prolonged mechanical ventilation. Accordingly, we describe the effect of pulmonary rehabilitation in such a patient. CASE PRESENTATION: We examined a 63-year-old Japanese woman with hypoxic-ischemic encephalopathy after subarachnoid hemorrhage who required prolonged mechanical ventilation. Radiographic and computed tomographic images revealed atelectasis of the right upper lobe. In addition, this atelectasis reduced the tidal volume, minute volume, and oxygen saturation and caused an absence of breath sounds in the right upper lobe during auscultation. We aimed to ameliorate the patient's atelectasis and improve her ventilation parameters by using positioning and expiratory rib-cage compression after endotracheal suctioning. Specifically, the patient was seated in Fowler's position, and mild pressure was applied to the upper thorax during expiration, improving her inspiratory volume. Immediately, breath sounds were audible in the right upper lobe. Furthermore, resolution of the patient's atelectasis was confirmed with chest radiography performed on the same day. In addition, her ventilation parameters (tidal volume, minute volume, and oxygen saturation) improved. CONCLUSIONS: Our results indicate that physical therapists should consider application of specific positioning and expiratory rib-cage compression in patients who exhibit atelectasis because of prolonged mechanical ventilation.

Temporary positive expiratory pressure (TPEP) as an alternative approach in the treatment of persistent atelectasis in a patient with Steinert disease: a case report.

We describe the clinical case of a patient affected by Steinert disease with persistent dyspnea complicated by a complete obstructive atelectasis of left lower lung lobe. The atelectasis has been successfully treated using the TPEP machine, with resolution of radiological pattern and improvement of the symptoms.

Lung ultrasonography as a tool to guide perioperative atelectasis treatment bundle in head and neck cancer patients undergoing free flap reconstructive surgeries: a preliminary observational study / Ultrassonografia pulmonar como ferramenta para orientar o tratamento perioperatório de atelectasia em pacientes com câncer de cabeça e pescoço submetidos a cirurgia reconstrutiva com retalho livre: um estudo observacional preliminar

Abstract Introduction: General anesthesia causes pulmonary atelectasis within few minutes of induction. This can have significant impact on postoperative outcome of cancer patients undergoing prolonged reconstructive surgeries. Objective: The purpose of this study was to evaluate the impact of sonographically detected perioperative atelectasis on the need for postoperative oxygen supplementation, bronchodilator therapy and assisted chest physiotherapy in patients undergoing free flap surgeries for head and neck carcinoma. Methods: Twenty eight head and neck cancer patients underwent bilateral pulmonary ultrasonographic assessments before and after lung surgery. Lung ultrasound scores, serum lactate, and PaO2/FiO2 ratio were measured both at the beginning and at end of the surgery. Patients were scanned in the supine position and the number of single and confluent B lines was noted. These values were correlated with the need for oxygen therapy, requirement of bronchodilators and total weaning time to predict the postoperative outcome. Other factors affecting weaning were also studied. Results: Among twenty eight patients, seven had mean lung ultrasound score of ≥10.5 which correlated with prolonged weaning time (144.56±33.5min vs. 66.7±15.7min; p = 0.005). The change in lung ultrasound score significantly correlated with change in PaO2/FiO2 ratio (r = −0.56, p = 0.03). Elevated total leukocyte count >8200 ΜL and serum lactate >2.1 mmoL/L also predicted prolonged postoperative mechanical ventilation. Conclusion: This preliminary study detected significant levels of perioperative atelectasis using point of care lung ultrasonography in head and neck cancer patients undergoing long duration surgical reconstructions. Higher lung ultrasound scores highlighted the need for frequent bronchodilator nebulizations as well as assisted chest physiotherapy and were associated with delayed weaning. We propose more frequent point of care lung ultrasonographic evaluations and use of recruitment maneuvers to reduce the impact of perioperative pulmonary atelectasis.

Resumo Introdução: A anestesia geral causa atelectasia pulmonar poucos minutos após sua indução. Isso pode ter um impacto significativo no resultado pós-operatório de pacientes com câncer submetidos a cirurgias reconstrutivas prolongadas. Objetivo: Avaliar o impacto das atelectasias perioperatórias detectadas por ultrassonografia na necessidade de suplementação pós-operatória de oxigênio, terapia broncodilatadora e fisioterapia respiratória assistida em pacientes com carcinoma de cabeça e pescoço submetidos a cirurgias com uso de retalho livre. Método: Foram submetidos a avaliações ultrassonográficas pulmonares bilaterais antes e após a cirurgia 28 pacientes com câncer de cabeça e pescoço. Os escores de ultrassonografia pulmonar, lactato sérico, razão PaO2/FiO2 foram medidos no início e no fim da cirurgia. Os pacientes foram avaliados na posição supina e o número de linhas B confluentes e únicas foi observado. Esses valores foram correlacionados com a necessidade de oxigenoterapia, necessidade de broncodilatadores e tempo total de desmame para predizer o resultado pós-operatório. Outros fatores que afetam o desmame também foram estudados. Resultados: Entre os 28 pacientes, sete apresentaram escore médio de ultrassonografia pulmonar ≥ 10,5, que se correlacionou com o tempo de desmame prolongado (144,56 ± 33,5 minutos vs. 66,7 ± 15,7 minutos; p = 0,005). A mudança no escore de ultrassonografia pulmonar correlacionou-se significantemente com a mudança na razão PaO2/FiO2 (r = −0,56, p = 0,03). A contagem total elevada de leucócitos > 8200 uLe o nível de lactato sérico >2,1 mmoL/L também previram ventilação mecânica pós-operatória prolongada. Conclusão: Este estudo preliminar detectou um nível significante de atelectasia perioperatória com ultrassonografia pulmonar no local de atendimento em pacientes com câncer de cabeça e pescoço submetidos a reconstruções cirúrgicas de longa duração. Escores mais altos de ultrassonografia pulmonar enfatizaram a necessidade de nebulizações broncodilatadoras frequentes e fisioterapia respiratória assistida e foram associados a desmame tardio. Propomos avaliações ultrassonográficas pulmonares mais frequentes no local de atendimento e o uso de manobras de recrutamento para reduzir o impacto das atelectasias pulmonares perioperatórias.

Effect of manual hyperinflation on recurrent atelectasis in a ventilator-dependent C3 complete spinal cord injury patient: A case report.

CLINICAL CASE: We present here the case of a ventilator-dependent 76-year-old man with C3 complete spinal cord injury (SCI) who presented with recurrent left lung atelectasis managed with manual hyperinflation (MH). Atelectasis was primarily assessed with chest X-ray (CXR). Additional monitoring included blood gas analysis, serum procalcitonin, and the Modified Borg Dyspnea Scale (MBS), as an objective measure of reported dyspnea. We found that MH successfully reversed the radiographic appearance of atelectasis after the first treatment and maintained this effect for the duration of the 2-week intervention period as well as at 2 weeks of follow-up post-intervention. Furthermore, MH decreased the patient's oxygen requirements and was associated with a decrease in serum procalcitonin. Clinically, the patient reported reduced subjective dyspnea post-MH, which was reflected as an improvement on the MBS. We conclude that MH may represent a therapeutic modality for consideration in the routine management of recurrent atelectasis in mechanically ventilated patients.

Lung ultrasonography as a tool to guide perioperative atelectasis treatment bundle in head and neck cancer patients undergoing free flap reconstructive surgeries: a preliminary observational study.

INTRODUCTION: General anesthesia causes pulmonary atelectasis within few minutes of induction. This can have significant impact on postoperative outcome of cancer patients undergoing prolonged reconstructive surgeries. OBJECTIVE: The purpose of this study was to evaluate the impact of sonographically detected perioperative atelectasis on the need for postoperative oxygen supplementation, bronchodilator therapy and assisted chest physiotherapy in patients undergoing free flap surgeries for head and neck carcinoma. METHODS: Twenty eight head and neck cancer patients underwent bilateral pulmonary ultrasonographic assessments before and after lung surgery. Lung ultrasound scores, serum lactate, and PaO2/FiO2 ratio were measured both at the beginning and at end of the surgery. Patients were scanned in the supine position and the number of single and confluent B lines was noted. These values were correlated with the need for oxygen therapy, requirement of bronchodilators and total weaning time to predict the postoperative outcome. Other factors affecting weaning were also studied. RESULTS: Among twenty eight patients, seven had mean lung ultrasound score of ≥10.5 which correlated with prolonged weaning time (144.56±33.5min vs. 66.7±15.7min; p=0.005). The change in lung ultrasound score significantly correlated with change in PaO2/FiO2 ratio (r=-0.56, p=0.03). Elevated total leukocyte count >8200µL and serum lactate >2.1mmoL/L also predicted prolonged postoperative mechanical ventilation. CONCLUSION: This preliminary study detected significant levels of perioperative atelectasis using point of care lung ultrasonography in head and neck cancer patients undergoing long duration surgical reconstructions. Higher lung ultrasound scores highlighted the need for frequent bronchodilator nebulizations as well as assisted chest physiotherapy and were associated with delayed weaning. We propose more frequent point of care lung ultrasonographic evaluations and use of recruitment maneuvers to reduce the impact of perioperative pulmonary atelectasis.

Perioperative Pulmonary Atelectasis: Part II. Clinical Implications.

The development of pulmonary atelectasis is common in the surgical patient. Pulmonary atelectasis can cause various degrees of gas exchange and respiratory mechanics impairment during and after surgery. In its most serious presentations, lung collapse could contribute to postoperative respiratory insufficiency, pneumonia, and worse overall clinical outcomes. A specific risk assessment is critical to allow clinicians to optimally choose the anesthetic technique, prepare appropriate monitoring, adapt the perioperative plan, and ensure the patient's safety. Bedside diagnosis and management have benefited from recent imaging advancements such as lung ultrasound and electrical impedance tomography, and monitoring such as esophageal manometry. Therapeutic management includes a broad range of interventions aimed at promoting lung recruitment. During general anesthesia, these strategies have consistently demonstrated their effectiveness in improving intraoperative oxygenation and respiratory compliance. Yet these same intraoperative strategies may fail to affect additional postoperative pulmonary outcomes. Specific attention to the postoperative period may be key for such outcome impact of lung expansion. Interventions such as noninvasive positive pressure ventilatory support may be beneficial in specific patients at high risk for pulmonary atelectasis (e.g., obese) or those with clinical presentations consistent with lung collapse (e.g., postoperative hypoxemia after abdominal and cardiothoracic surgeries). Preoperative interventions may open new opportunities to minimize perioperative lung collapse and prevent pulmonary complications. Knowledge of pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should provide the basis for current practice and help to stratify and match the intensity of selected interventions to clinical conditions.

Impact of airway and a standardized recruitment maneuver on CT chest imaging quality in a pediatric population: A retrospective review.

INTRODUCTION: When performing computerized tomography chest imaging in children, obtaining high quality, motion-free images is important in the accurate diagnosis of underlying pathology. General anesthesia is associated with the development of atelectasis, which can impair accurate diagnosis by obscuring or altering the appearance of the lung parenchyma or airways. Recruitment maneuvers, performed by anesthesiologists, can be used to effectively re-expand atelectatic lung. METHODS: The computerized tomography chest imaging in 44 children aged between 2 months and 7 years, undergoing serial imaging for monitoring of cystic fibrosis, were reviewed and graded for atelectasis. The first scan performed on each child was performed with a supraglottic airway device and a non-standardized recruitment maneuver. The second scan on each child was performed with a cuffed endotracheal tube and a standardized recruitment maneuver. RESULTS: When a supraglottic airway device and a non-standardized recruitment maneuver were used, 77% of patients demonstrated atelectasis of any degree on their computerized tomography chest imaging, compared with only 39% when a cuffed endotracheal tube and standardized recruitment maneuver were used. The percentage of computerized tomography chest scans that were scored acceptable (with either a total combined lung atelectasis score of 0 or 1) improved from 37% to 75% when a cuffed endotracheal tube and standardized recruitment maneuver were used. In particular, the mean atelectasis score for both lungs improved from 2.91 (SD ± 2.6) to 1.11 (SD ± 1.9), with a mean difference of 1.8 (95% CI 0.82-2.77; p: .0004). CONCLUSION: The use of a cuffed endotracheal tube and a standardized recruitment maneuver is an effective way to reduce atelectasis as a result of general anesthesia. Anesthesiologists can actively contribute toward improved image quality through their choice of airway and recruitment maneuver.

Perioperative Pulmonary Atelectasis: Part I. Biology and Mechanisms.

Pulmonary atelectasis is common in the perioperative period. Physiologically, it is produced when collapsing forces derived from positive pleural pressure and surface tension overcome expanding forces from alveolar pressure and parenchymal tethering. Atelectasis impairs blood oxygenation and reduces lung compliance. It is increasingly recognized that it can also induce local tissue biologic responses, such as inflammation, local immune dysfunction, and damage of the alveolar-capillary barrier, with potential loss of lung fluid clearance, increased lung protein permeability, and susceptibility to infection, factors that can initiate or exaggerate lung injury. Mechanical ventilation of a heterogeneously aerated lung (e.g., in the presence of atelectatic lung tissue) involves biomechanical processes that may precipitate further lung damage: concentration of mechanical forces, propagation of gas-liquid interfaces, and remote overdistension. Knowledge of such pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should guide optimal clinical management.

Targeted lateral positioning decreases lung collapse and overdistension in COVID-19-associated ARDS.

BACKGROUND: Among the challenges for personalizing the management of mechanically ventilated patients with coronavirus disease (COVID-19)-associated acute respiratory distress syndrome (ARDS) are the effects of different positive end-expiratory pressure (PEEP) levels and body positions in regional lung mechanics. Right-left lung aeration asymmetry and poorly recruitable lungs with increased recruitability with alternating body position between supine and prone have been reported. However, real-time effects of changing body position and PEEP on regional overdistension and collapse, in individual patients, remain largely unknown and not timely monitored. The aim of this study was to individualize PEEP and body positioning in order to reduce the mechanisms of ventilator-induced lung injury: collapse and overdistension. METHODS: We here report a series of five consecutive mechanically ventilated patients with COVID-19-associated ARDS in which sixteen decremental PEEP titrations were performed in the first days of mechanical ventilation (8 titration pairs: supine position immediately followed by 30° targeted lateral position). The choice of lateral tilt was based on X-Ray. This targeted lateral position strategy was defined by selecting the less aerated lung to be positioned up and the more aerated lung to be positioned down. For each PEEP level, global and regional collapse and overdistension maps and percentages were measured by electrical impedance tomography. Additionally, we present the incidence of lateral asymmetry in a cohort of forty-four patients. RESULTS: The targeted lateral position strategy resulted in significantly smaller amounts of overdistension and collapse when compared with the supine one: less collapse along the PEEP titration was found within the left lung in targeted lateral (P = 0.014); and less overdistension along the PEEP titration was found within the right lung in targeted lateral (P = 0.005). Regarding collapse within the right lung and overdistension within the left lung: no differences were found for position. In the cohort of forty-four patients, ventilation inequality of > 65/35% was observed in 15% of cases. CONCLUSIONS: Targeted lateral positioning with bedside personalized PEEP provided a selective attenuation of overdistension and collapse in mechanically ventilated patients with COVID-19-associated ARDS and right-left lung aeration/ventilation asymmetry. TRIAL REGISTRATION: Trial registration number: NCT04460859.

Acute hypoxemia due to lung collapse in COVID-19: the role of therapeutic bronchoscopy.

Bronchoscopy is an aerosol-generating procedure and involves a high risk of transmission of SARS-CoV-2 to health care workers. There are very few indications for performing bronchoscopy in a patient with confirmed COVID-19. These include atelectasis, foreign body aspiration, and suspected superinfection in immunocompromised patients. Proper use of standard personal protective equipment is mandatory to reduce the risk of transmission to health care workers. In this article, we describe a case of acute lung collapse in a 16-year-old boy with cerebral palsy who was infected with COVID-19. This patient responded to therapeutic bronchoscopy and had complete resolution of lung collapse within 24 hours of the procedure.