Clinical validation of the Air-Test for the non-invasive detection of perioperative atelectasis in children

BACKGROUND

The incidence of anesthesia-induced atelectasis in children is high and closely related to episodes of hypoxemia. The Air-Test is a simple maneuver to detect lung collapse. By a step-reduction in FiO2 to 0.21, a fall in pulse-oximetry hemoglobin saturation <97% unmasks the presence of collapse-related shunt in healthy lungs. The aim of this study was to validate the Air-Test as a diagnostic tool to detect perioperative atelectasis in children using lung ultrasound as a reference.

METHODS

We first assessed the Air-Test in a retrospective cohort of 88 anesthetized children (Retrospective study) followed by a prospective study performed in 72 children (45 postconceptional weeks to 16 years old) using a similar protocol (Validation study). We analyzed the performance of the Air-Test to detect atelectasis by an operating characteristic curve (ROC) analysis, using lung ultrasound consolidation score as reference.

RESULTS

Preoperative SpO2 was normal in both studies (retrospective 98.7±0.6%, validation 99.0±0.9%). The Air-Test, with a SpO2 cut point <97%, resulted positive in 67 patients in the retrospective study (SpO2 93.3±2.1%) and in 59 in the validation study (SpO2 94.9±1.8%); both P<0.0001. In the validation study, the Air-Test showed a sensitivity of 0.91 (95% CI 0.85-0.92), specificity of 1.00 (95% CI 0.84-1) and an area under the curve (AUC) of 0.98 (95% CI 0.97-1.00). AUC between both studies was similar (P=0.16).

CONCLUSIONS

The Air-Test is a noninvasive and accurate method to detect atelectasis in healthy anesthetized children. It can be used as a screening tool to individualize patients that can benefit from lung recruitment maneuvers.

Should atelectasis be considered a pulmonary complication and indicator of poor prognosis in cystic fibrosis?

OBJECTIVE

This study examined whether bronchoscopy leads to clinicoradiological improvement in cystic fibrosis (CF) and the predictive factors. The study also investigated whether pulmonary atelectasis is a poor prognostic factor in CF.

METHODS

This multicenter, case-control, observational, retrospective study included two groups of patients with CF: a case group (patients with persistent atelectasis who were followed-up at least for 2 years) and a control group (patients without atelectasis matched 1:1 by sex and age [±3 years]). We recorded demographic data, lung function test results, pulmonary complications, comorbidities, treatments (including bronchoscopies, surgery and transplantation), and deaths.

RESULTS

Each group included 55 patients (case group: 20 men, mean age 25.4 ± 10.4 years; control group: 20 men, mean age 26.1 ± 11.4 years). Bronchoscopy did not lead to clinicoradiological improvement. Allergic bronchopulmonary aspergillosis (ABPA) was more frequent in the case group. Patients in the case group more frequently used inhaled steroids, their pre-atelectasis lung function was statistically worse, and they had more exacerbations during follow-up.

CONCLUSION

Moderate-to-severe pulmonary disease and ABPA can favor atelectasis. Pulmonary atelectasis can be a poor prognostic factor in CF because it increases exacerbations. Despite our results, we recommend enhancing treatment, including bronchoscopy, to prevent persistent atelectasis.

Arterial partial pressure of oxygen as a marker of airway closure does not correlate with the efficacy of pre-oxygenation: A prospective cohort study

BACKGROUND

The prerequisites for the early formation of anaesthesia-related atelectasis are pre-oxygenation with its resulting high alveolar oxygen content, and airway closure. Airway closure increases with age, so it seems counterintuitive that atelectasis formation during anaesthesia does not. One proposed explanation is that pre-oxygenation is impaired in the elderly by airway closure present in the waking state. The extent of airway closure cannot be assessed at the bedside, but arterial partial pressure of oxygen ( Pa O 2 ) as a surrogate variable of the resulting ventilation to perfusion mismatch can.

OBJECTIVE

The primary aim was to test the hypothesis that a decreased efficacy of pre-oxygenation, measured as the fraction of end-tidal oxygen (F E' O 2 ) after 3 min of pre-oxygenation, correlates with decreased Pa O 2 on room air. We also re-investigated the influence on F E' O 2 by age.

DESIGN

Prospective observational study.

SETTING

Two regional hospitals, Västerås and Köping County Hospitals, Västmanland, Sweden, between 30 October 2018 and 17 September 2021.

PARTICIPANTS

We included 120 adults aged 40 to 79 years presenting for elective noncardiac surgery.

INTERVENTION

An arterial blood gas was sampled before commencing pre-oxygenation.

RESULTS

No linear correlation was found between F E' O 2 at 3 min and Pa O 2 or age (Pearson's r  = -0.038, P  = 0.684; and Pearson's r  = -0.113, P  = 0.223, respectively). The mean ± SD F E' O 2 at 3 min for the population studied was 0.87 ± 0.05.

CONCLUSION

The lack of correlation between F E' O 2 at 3 min and Pa O 2 or age during pre-oxygenation has implications for further studies concerning the interaction between airway closure and atelectasis. After 3 min of pre-oxygenation, F E' O 2 , even in the elderly, indicated a high enough alveolar oxygen concentration to promote atelectasis after induction, therefore, it is still unclear why atelectasis formation diminishes after middle age.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03395782.

[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.

[Recurrent atelectasis in an infant : about one case of false-negative newborn screening for cystic fibrosis]

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.

Transient Vertigo with Horizontal Nystagmus to Loud Noise and Pressure: Utricular Hydrops or Vestibular Atelectasis?

We present an unusual case of a patient with a positive Tullio phenomenon, brief Valsalva-induced transient horizontal nystagmus, reduced left caloric response, and bilateral vestibulo-ocular reflex loss. This study discusses the pathophysiology and differential diagnosis concerning the suspected pathology for the phenomenon of utricular hydrops or vestibular atelectasis and presents a literature review.

Right Upper Lobe Collapse Secondary to an Anomalous Bronchus after Endotracheal Intubation for Routine Surgery

Perioperative hypoxaemia is a common but serious problem with well recognised causes. However, an anomalous bronchus causing lobar collapse as a cause is seldom mentioned. A healthy young male patient was anaesthetised for a knee operation. He required reintubation immediately postoperatively for hypoxia. He was found to have right upper lobe collapse. Fibreoptic examination of the trachea demonstrated an anomalous bronchus as the cause. Intra-operatively, the endotracheal tube had been inserted too deeply and the bronchial orifice had been obstructed by the tip. It took several hours for the lung to re-expand. Greater awareness of this potential complication is needed.

The accuracy of postoperative, non-invasive Air-Test to diagnose atelectasis in healthy patients after surgery: a prospective, diagnostic pilot study

OBJECTIVE

To assess the diagnostic accuracy of peripheral capillary oxygen saturation (SpO₂) while breathing room air for 5 min (the 'Air-Test') in detecting postoperative atelectasis.

DESIGN

Prospective cohort study. Diagnostic accuracy was assessed by measuring the agreement between the index test and the reference standard CT scan images.

SETTING

Postanaesthetic care unit in a tertiary hospital in Spain.

PARTICIPANTS

Three hundred and fifty patients from 12 January to 7 February 2015; 170 patients scheduled for surgery under general anaesthesia who were admitted into the postsurgical unit were included.

INTERVENTION

The Air-Test was performed in conscious extubated patients after a 30 min stabilisation period during which they received supplemental oxygen therapy via a venturi mask. The Air-Test was defined as positive when SpO₂ was ≤96% and negative when SpO₂ was ≥97%. Arterial blood gases were measured in all patients at the end of the Air-Test. In the subsequent 25 min, the presence of atelectasis was evaluated by performing a CT scan in 59 randomly selected patients.

MAIN OUTCOME MEASURES

The primary study outcome was assessment of the accuracy of the Air-Test for detecting postoperative atelectasis compared with the reference standard. The secondary outcome was the incidence of positive Air-Test results.

RESULTS

The Air-Test diagnosed postoperative atelectasis with an area under the receiver operating characteristic curve of 0.90 (95% CI 0.82 to 0.98) with a sensitivity of 82.6% and a specificity of 87.8%. The presence of atelectasis was confirmed by CT scans in all patients (30/30) with positive and in 5 patients (17%) with negative Air-Test results. Based on the Air-Test, postoperative atelectasis was present in 36% of the patients (62 out of 170).

CONCLUSION

The Air-Test may represent an accurate, simple, inexpensive and non-invasive method for diagnosing postoperative atelectasis.

TRIAL REGISTRATION

NCT02650037.

[Diagnosis of pulmonary hemorrhage of the newborn infants using lung ultrasonography]

Objective: To investigate the accuracy and reliability of lung ultrasound in diagnosis of pulmonary hemorrhage of the newborn infants. Method: From January 2014 to May 2016, 142 neonates from the Army General Hospital of the Chinese PLA were enrolled in the study. They were divided into two groups: a study group of 42 neonates, who were diagnosed with pulmonary hemorrhage according to their medical history, clinical manifestations and chest X-ray findings, and a control group of 100 neonates with no lung disease. All subjects underwent bedside lung ultrasound in a quiet state in a supine, lateral or prone posture, performed by a single experienced physician. The ultrasound findings were compared between the two groups.Fisher's exact test was uesd for comparison between two groups. Result: The lung ultrasound main findings associated with pulmonary hemorrhage included: (1) Shred sign: which was seen in 40 patients(95%). (2) Lung consolidation with air bronchograms: which were seen in 35 patients(83%). (3) Pleural effusion: which was seen in 34 infants(81%), pleurocentesis confirmed that the fluid was really bleeding.(4)Atelectasis: which was seen in 14 cases(33%). (5) Pleural line abnormalities and disappearing A-lines with an incidence of 100%. (6) Alveolar-interstitial syndrome: 5 patients(12%)had the main manifestations of alveolar-interstitial syndrome. The above signs were not seen in normal controls (all P<0.01) and the normal lung mainly manifested with clear pleural line and A-lines under ultrasound. Conclusion: Lung ultrasonography is accurate and reliable for diagnosing pulmonary hemorrhage, which is suitable for routine application for the diagnosis of pulmonary hemorrhage in the neonatal intensive care unit.

Left upper lobe atelectasis due to plastic bronchitis

Şişmanlar T, Aslan AT, Öztunalı Ç, Boyunağa Ö. Left upper lobe atelectasis due to plastic bronchitis. Turk J Pediatr 2017; 59: 207-209. Plastic bronchitis is a rare condition in children, characterized by expectoration of branching bronchial casts. It can cause atelectasis in the lung. Herein we reported a 4.5-year-old boy with left upper lobe atelectasis due to plastic bronchitis. Although his chest X-ray is specific for left upper left atelectasis, thoracic computerized tomography had been performed and was compatible with obliterated left upper lobe bronchus. Typical radiological appearance of the left upper lobe atelectasis is not well known by clinicians which results unnecessary further examinations such as computerized tomography which exposes high dose radiation. We want to emphasize the long-term side effects of radiation and avoid unnecessary examinations in children.

Traumatic lung injury attributed to tornadic activity-induced barometric pressure changes in two dogs

CASE DESCRIPTION A 7-year-old castrated male Italian Greyhound (dog 1) and an approximately 1-year-old female Labrador Retriever (dog 2) were evaluated because of respiratory distress 8 and 10 days, respectively, after a tornado. CLINICAL FINDINGS No obvious external injuries were identified auscultation revealed decreased bronchovesicular sounds in the affected hemithorax of both dogs. Clinicopathologic changes were mild, with evidence of inflammation in both dogs. Thoracic radiography of both dogs revealed pneumothorax and pleural effusion with effacement of the diaphragm; findings on CT included severe pulmonary atelectasis of affected lung lobes with normal bronchial tree configurtion and no evidence of diaphragmatic hernia. TREATMENT AND OUTCOME Exploratory thoracotomy of both dogs confirmed CT findings Pulmonary parenchymal damage consistent with a large rupture was found in both patients. A large hematoma was adhered to the ruptured lung lobe of dog 1. Grossly affected lung tissue was removed; histologic examination revealed atelectasis, pulmonary fib osis, thrombosis, and minimal (dog 1) to marked (dog 2) inflammation Microbial culture of lung tissue yielded no growth for dog 1 and Streptococcus spp and Escherichia coli susceptible to amoxicillin-clavulanic acid for dog 2. Dog 1 had a recurrence of pneumothorax treated by drainage with a thoracostomy tube 1 month after surgery. Eighteen months after surgery, both dogs were reportedly doing well. CLINICAL RELEVANCE Development of clinical signs after a tornado, together with clinical, diagnostic imaging, surgical, and histologic findings led to a presumptive diagnosis of pulmonary barotrauma for both dogs. Long-term outcome for these dogs, treated at a referral hospital, was good.

Hyperpolarized gas diffusion MRI for the study of atelectasis and acute respiratory distress syndrome

Considerable uncertainty remains about the best ventilator strategies for the mitigation of atelectasis and associated airspace stretch in patients with acute respiratory distress syndrome (ARDS). In addition to several immediate physiological effects, atelectasis increases the risk of ventilator-associated lung injury, which has been shown to significantly worsen ARDS outcomes. A number of lung imaging techniques have made substantial headway in clarifying the mechanisms of atelectasis. This paper reviews the contributions of computed tomography, positron emission tomography, and conventional MRI to understanding this phenomenon. In doing so, it also reveals several important shortcomings inherent to each of these approaches. Once these shortcomings have been made apparent, we describe how hyperpolarized (HP) gas MRI--a technique that is uniquely able to assess responses to mechanical ventilation and lung injury in peripheral airspaces--is poised to fill several of these knowledge gaps. The HP-MRI-derived apparent diffusion coefficient (ADC) quantifies the restriction of (3) He diffusion by peripheral airspaces, thereby obtaining pulmonary structural information at an extremely small scale. Lastly, this paper reports the results of a series of experiments that measured ADC in mechanically ventilated rats in order to investigate (i) the effect of atelectasis on ventilated airspaces, (ii) the relationship between positive end-expiratory pressure (PEEP), hysteresis, and the dimensions of peripheral airspaces, and (iii) the ability of PEEP and surfactant to reduce airspace dimensions after lung injury. An increase in ADC was found to be a marker of atelectasis-induced overdistension. With recruitment, higher airway pressures were shown to reduce stretch rather than worsen it. Moving forward, HP MRI has significant potential to shed further light on the atelectatic processes that occur during mechanical ventilation.

[Factors associated with atelectasis following extubation in very low weight premature newborns]

BACKGROUND

Atelectasis is a decrease of lung volume caused by airway obstruction or pressure on the external part of the lung. It is common after surgery and extubation. The purpose of this investigation was to determine factors related with alectasis following extubation in preterm neonates with a weight under 1250 g who were referred to a neonatal intensive care unit.

METHODS

The study was conducted in neonates admitted to a neonatal intensive care unit requiring mechanically assisted ventilation. Preterm neonates born at 28 to 36 weeks' gestation and with 0 to 28 days' extrauterine life, with mechanically assisted ventilation for at least 24 hours, and that when undergoing planned extubation had a weight under 1250 g were included. Two comparative groups were formed: group A, with alectasis after extubation; group B, without alectasis after extubation.

RESULTS

As factors associated with alectasis after extubation, reintubation in two or more occasions and cycling higher than 20 per minute, which were statistically relevant, were identified.

CONCLUSIONS

In addition to previous general measures to prevent alectasis, extubation with ventilation not higher tan 20 cycles per minute should be programmed and reintubation should be avoided as much as possible.

[Analysis on diagnosis and treatment of 15 cases with severe influenza A]

OBJECTIVE

To analyze the diagnosis and treatment characteristics of patients with severe Influenza A.

METHOD

A retrospective investigation on the clinical manifestation, chest radiography, electronic fiber bronchoscopy and the histology of the cast, rescue course and outcome was conducted in 15 children with severe influenza A during January to May of 2013.

RESULT

Eleven cases were male, the range of age was 2 to 6 years; 5 cases were female, the range of age was 1 month to 6 years, accouting for 4.2% of hospitalized children with influenza. Three patients had an underlying chronic disease, two had nephrotic syndrome, and one had congenital heart disease. All the 15 cases were diagnosed as severe influenza A virus infection complicated with pneumonia and respiratory failure, of whom 10 cases were infected with H1N1 virus , the other 5 cases could not be identified as H1N1 virus by using H1N1 kit, but none of the 15 cases were infected with H7N9 virus. Of 15 cases, 8 had atelectasis, 4 had pneumothorax, 3 had pneumomediastinum, 4 had pleural effusion, 1 had pneumorrhagia; 12 patients required mechanical ventilation. 1 only required noninvasive mask CPAP, 2 did not require assisted ventilation, they were just given mask oxygen. Seven cases' sputum culture showed combined infection with bacteria and fungi, sputum smear examination detected: G(+) cocci in 2 cases, and G(-) bacilli in the other 2. By using electronic fiber bronchoscopy, bronchial cast was detected in 5 patiens. Histological examination of the bronchial cast revealed a fibrinous exudation containing large quantity of eosinophils, neutrophils in 1 patients, fibrinous exudation and necrotic material containing large quantity of neutrophils in 4 patients. After the bronchial casts were removed, 4 patients were improved greatly. All patients were treated with postural drainage of left and right side position, massage of electric oscillation, strengthening the sputum suction aiming to improve pulmonary ventilation function. Three patients died: 1 case was compliicated with nephrotic syndrome, another case had congenital heart disease, and 1 case hads pneumorrhagia, renal failure and multiple organ dysfunction syndrome (MODS).

CONCLUSION

The mortality of severe Influenza A is higher if it is complicated with underlying chronic diseases. In children undergoing rapid and progressive respiratory distress with lung atelectasis, consolidation or emphysema on chest X-ray, plastic bronchitis should be considered. Electronic fiber bronchoscopy should be performed early Lung physicotherapeutics still are important assistant measures for improving the pulmonary ventilation function.

[Emergency fiberoptic bronchoscopy for diagnostics and treatment of lung atelectasis]

The article deals with results of fiberoptic bronchoscopy using during treating of patients suffering atelectasis. According to the research atelectasis is likely to advance in the first three days after serious patients have been admitted to the intensive therapy unit or after operative treatment. Left-sided atelectasis is half as widespread again the right-sided one. The research highlights the effectiveness of atelectasis X-ray diagnosis. Fiberoptic bronchoscopy in almost all the cases allowed diagnosing the degree of tracheobronchial tree obstruction and its causes. Single suction fiberoptic bronchoscopy leads to normalization and encouraged positive dynamics in 76% of all the cases (57 patients). Repeated endoscopic sanation in the first two days was necessary for 25 patients (25.3%) with unresolved or reoccurring atelectasis. The effectiveness of second research was to 84%. It's important to add that mostly patients with serious chest injury were subjected to unresolved or reoccurring atelectasis. And mainly in these cases blood was seen through the tracheobronchial tree lumen.