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The Clinical Respiratory Journal Nov 2022This study aimed to present a review on the general effects of different positive end-expiratory pressure (PEEP) levels during thoracic surgery by qualitatively... (Review)
Review
OBJECTIVES
This study aimed to present a review on the general effects of different positive end-expiratory pressure (PEEP) levels during thoracic surgery by qualitatively categorizing the effects into detrimental, beneficial, and inconclusive.
DATA SOURCE
Literature search of Pubmed, CNKI, and Wanfang was made to find relative articles about PEEP levels during thoracic surgery. We used the following keywords as one-lung ventilation, PEEP, and thoracic surgery.
RESULTS
We divide the non-individualized PEEP value into five grades, that is, less than 5, 5, 5-10, 10, and more than 10 cmH O, among which 5 cmH O is the most commonly used in clinic at present to maintain alveolar dilatation and reduce the shunt fraction and the occurrence of atelectasis, whereas individualized PEEP, adjusted by test titration or imaging method to adapt to patients' personal characteristics, can effectively ameliorate intraoperative oxygenation and obtain optimal pulmonary compliance and better indexes relating to respiratory mechanics.
CONCLUSIONS
Available data suggest that PEEP might play an important role in one-lung ventilation, the understanding of which will help in exploring a simple and economical method to set the appropriate PEEP level.
Topics: Humans; Lung Compliance; Thoracic Surgery; Positive-Pressure Respiration; Respiratory Mechanics; Pulmonary Atelectasis
PubMed: 36181340
DOI: 10.1111/crj.13545 -
Anaesthesia Dec 2011Airway management is primarily designed to avoid hypoxia, yet hypoxia remains the main ultimate cause of anaesthetic-related death and morbidity. Understanding some of... (Review)
Review
Airway management is primarily designed to avoid hypoxia, yet hypoxia remains the main ultimate cause of anaesthetic-related death and morbidity. Understanding some of the physiology of hypoxia is therefore essential as part of a 'holistic' approach to airway management. Furthermore, it is strategically important that national specialist societies dedicated to airway management do not only focus upon the technical aspects of airway management, but also embrace some of the relevant scientific questions. There has been a great deal of research into causation of hypoxia and the body's natural protective mechanisms and responses to it. This enables us to think of ways in which we might manipulate the cellular and molecular responses to confer greater protection against hypoxia-induced tissue injury. This article reviews some of those aspects.
Topics: Adaptation, Physiological; Airway Management; Analgesics, Opioid; Anesthesia Recovery Period; Anesthesia, Inhalation; Anesthetics, Inhalation; Humans; Hypoxia; Mitochondria; Pulmonary Atelectasis; Respiration, Artificial; Respiratory Mechanics
PubMed: 22074075
DOI: 10.1111/j.1365-2044.2011.06930.x -
Journal of Medical Case Reports Jun 2022Pulmonary complications can be caused by intraoperative mechanical ventilation. In particular, prolonged mechanical ventilation is associated with a high mortality rate,...
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.
Topics: Female; Humans; Lung; Middle Aged; Pressure; Pulmonary Atelectasis; Respiration, Artificial; Respiratory Sounds; Ribs
PubMed: 35739590
DOI: 10.1186/s13256-022-03389-5 -
PloS One 2015Atelectasis can provoke pulmonary and non-pulmonary complications after general anaesthesia. Unfortunately, there is no instrument to estimate atelectasis and prompt...
BACKGROUND
Atelectasis can provoke pulmonary and non-pulmonary complications after general anaesthesia. Unfortunately, there is no instrument to estimate atelectasis and prompt changes of mechanical ventilation during general anaesthesia. Although arterial partial pressure of oxygen (PaO2) and intrapulmonary shunt have both been suggested to correlate with atelectasis, studies yielded inconsistent results. Therefore, we investigated these correlations.
METHODS
Shunt, PaO2 and atelectasis were measured in 11 sheep and 23 pigs with otherwise normal lungs. In pigs, contrasting measurements were available 12 hours after induction of acute respiratory distress syndrome (ARDS). Atelectasis was calculated by computed tomography relative to total lung mass (Mtotal). We logarithmically transformed PaO2 (lnPaO2) to linearize its relationships with shunt and atelectasis. Data are given as median (interquartile range).
RESULTS
Mtotal was 768 (715-884) g in sheep and 543 (503-583) g in pigs. Atelectasis was 26 (16-47) % in sheep and 18 (13-23) % in pigs. PaO2 (FiO2 = 1.0) was 242 (106-414) mmHg in sheep and 480 (437-514) mmHg in pigs. Shunt was 39 (29-51) % in sheep and 15 (11-20) % in pigs. Atelectasis correlated closely with lnPaO2 (R2 = 0.78) and shunt (R2 = 0.79) in sheep (P-values<0.0001). The correlation of atelectasis with lnPaO2 (R2 = 0.63) and shunt (R2 = 0.34) was weaker in pigs, but R2 increased to 0.71 for lnPaO2 and 0.72 for shunt 12 hours after induction of ARDS. In both, sheep and pigs, changes in atelectasis correlated strongly with corresponding changes in lnPaO2 and shunt.
DISCUSSION AND CONCLUSION
In lung-healthy sheep, atelectasis correlates closely with lnPaO2 and shunt, when blood gases are measured during ventilation with pure oxygen. In lung-healthy pigs, these correlations were significantly weaker, likely because pigs have stronger hypoxic pulmonary vasoconstriction (HPV) than sheep and humans. Nevertheless, correlations improved also in pigs after blunting of HPV during ARDS. In humans, the observed relationships may aid in assessing anaesthesia-related atelectasis.
Topics: Anesthesia, General; Animals; Humans; Lung; Partial Pressure; Pulmonary Atelectasis; Pulmonary Gas Exchange; Respiration, Artificial; Respiratory Distress Syndrome; Sheep; Species Specificity; Swine; Tomography, X-Ray Computed; Vasoconstriction
PubMed: 26258686
DOI: 10.1371/journal.pone.0135272 -
Medicine Nov 2022The use of lung ultrasound for the diagnosis of pulmonary atelectasis remains controversial. Therefore, we performed a protocol for systematic review and meta-analysis...
BACKGROUND
The use of lung ultrasound for the diagnosis of pulmonary atelectasis remains controversial. Therefore, we performed a protocol for systematic review and meta-analysis to evaluate the diagnostic accuracy of lung ultrasound for the diagnosis of pulmonary atelectasis both in adults and pediatrics.
METHODS
A comprehensive search of several databases from 1966 to October 2022 will be conducted. The databases include Ovid Medline In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, Ovid PsycINFO, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and PubMed. After screening and diluting out the articles that met inclusion criteria to be used for statistical analysis, the pooled evaluation indexes including sensitivity and specificity as well as hierarchical summary receiver operating characteristic curves with 95% confidence interval were calculated. All statistical analyses were calculated with STATA, version 12.0 (StataCorp, College Station, TX).
RESULT
We will synthesize the current studies to evaluate the diagnostic accuracy of lung ultrasound for the diagnosis of pulmonary atelectasis.
CONCLUSION
The result of this review will provide more reliable references to help clinicians make decisions for the diagnosis of pulmonary atelectasis.
Topics: Humans; Child; Adult; Systematic Reviews as Topic; Meta-Analysis as Topic; Lung; Ultrasonography; Pulmonary Atelectasis; Review Literature as Topic
PubMed: 36401459
DOI: 10.1097/MD.0000000000031519 -
Arquivos Brasileiros de Cirurgia... 2014In surgical procedures, obesity is a risk factor for the onset of intra and postoperative respiratory complications. (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
In surgical procedures, obesity is a risk factor for the onset of intra and postoperative respiratory complications.
AIM
Determine what moment of application of positive pressure brings better benefits on lung function, incidence of atelectasis and diaphragmatic excursion, in the preoperative, intraoperative or immediate postoperative period.
METHOD
Randomized, controlled, blinded study, conducted in a hospital and included subjects with BMI between 40 and 55 kg/m2, 25 and 55 years, underwent bariatric surgery by laparotomy. They were underwent preoperative and postoperative evaluations. They were allocated into four different groups: 1) Gpre: treated with positive pressure in the BiPAP mode (Bi-Level Positive Airway Pressure) before surgery for one hour; 2) Gpos: BIPAP after surgery for one hour; 3) Gintra: PEEP (Positive End Expiratory Pressure) at 10 cmH2O during the surgery; 4) Gcontrol: only conventional respiratory physiotherapy. The evaluation consisted of anthropometric data, pulmonary function tests and chest radiography.
RESULTS
Were allocated 40 patients, 10 in each group. There were significant differences for the expiratory reserve volume and percentage of the predicted expiratory reserve volume, in which the groups that received treatment showed a smaller loss in expiratory reserve volume from the preoperative to postoperative stages. The postoperative radiographic analysis showed a 25% prevalence of atelectasis for Gcontrol, 11.1% for Gintra, 10% for Gpre, and 0% for Gpos. There was no significant difference in diaphragmatic mobility amongst the groups.
CONCLUSION
The optimal time of application of positive pressure is in the immediate postoperative period, immediately after extubation, because it reduces the incidence of atelectasis and there is reduction of loss of expiratory reserve volume.
Topics: Adult; Bariatric Surgery; Female; Humans; Lung; Male; Perioperative Care; Positive-Pressure Respiration; Postoperative Period; Prevalence; Pulmonary Atelectasis; Respiratory Function Tests; Single-Blind Method
PubMed: 25409961
DOI: 10.1590/s0102-6720201400s100007 -
Critical Care (London, England) Sep 2014When alveoli collapse the traction forces exerted on their walls by adjacent expanded units may increase and concentrate. These forces may promote its re-expansion at...
INTRODUCTION
When alveoli collapse the traction forces exerted on their walls by adjacent expanded units may increase and concentrate. These forces may promote its re-expansion at the expense of potentially injurious stresses at the interface between the collapsed and the expanded units. We developed an experimental model to test the hypothesis that a local non-lobar atelectasis can act as a stress concentrator, contributing to inflammation and structural alveolar injury in the surrounding healthy lung tissue during mechanical ventilation.
METHODS
A total of 35 rats were anesthetized, paralyzed and mechanically ventilated. Atelectasis was induced by bronchial blocking: after five minutes of stabilization and pre-oxygenation with FIO2 = 1.0, a silicon cylinder blocker was wedged in the terminal bronchial tree. Afterwards, the animals were randomized between two groups: 1) Tidal volume (VT) = 10 ml/kg and positive end-expiratory pressure (PEEP) = 3 cmH2O (VT10/PEEP3); and 2) VT = 20 ml/kg and PEEP = 0 cmH2O (VT20/zero end-expiratory pressure (ZEEP)). The animals were then ventilated during 180 minutes. Three series of experiments were performed: histological (n = 12); tissue cytokines (n = 12); and micro-computed tomography (microCT; n = 2). An additional six, non-ventilated, healthy animals were used as controls.
RESULTS
Atelectasis was successfully induced in the basal region of the lung of 26 out of 29 animals. The microCT of two animals revealed that the volume of the atelectasis was 0.12 and 0.21 cm3. There were more alveolar disruption and neutrophilic infiltration in the peri-atelectasis region than the corresponding contralateral lung (control) in both groups. Edema was higher in the peri-atelectasis region than the corresponding contralateral lung (control) in the VT20/ZEEP than VT10/PEEP3 group. The volume-to-surface ratio was higher in the peri-atelectasis region than the corresponding contralateral lung (control) in both groups. We did not find statistical difference in tissue interleukin-1β and cytokine-induced neutrophil chemoattractant-1 between regions.
CONCLUSIONS
The present findings suggest that a local non-lobar atelectasis acts as a stress concentrator, generating structural alveolar injury and inflammation in the surrounding lung tissue.
Topics: Animals; Inflammation; Interleukin-1beta; Lung; Male; Positive-Pressure Respiration; Pulmonary Alveoli; Pulmonary Atelectasis; Rats; Respiratory Mechanics; Tidal Volume; X-Ray Microtomography
PubMed: 25200702
DOI: 10.1186/s13054-014-0505-1 -
Zhongguo Fei Ai Za Zhi = Chinese... Mar 2010Atelectasis is a common complication after thoracotomy, and it may threaten patients' life if it was not treated correctly and properly. The aim of this article is to...
BACKGROUND AND OBJECTIVE
Atelectasis is a common complication after thoracotomy, and it may threaten patients' life if it was not treated correctly and properly. The aim of this article is to explore and discuss the prevention and treatment for atelectasis during the perioperative period, and also to explore new methods for reducing the perioperative mortality due to atelectasis after thoracotomy.
METHODS
We retrospectively reviewed the medical records of 374 lung cancer patients who underwent thoracotomy in our department between Jan 2007 and Nov 2009.
RESULTS
Atelectasis occurred in 14 patients among all the 374 lung cancer patients who underwent thoracotomy. All the atelectasis returned to reexpansion after treatment.
CONCLUSION
The incidence of atelectasis in these series is relatively low compared with the reports in literatures. Good perioperative preparation and perioperative treatment can remarkably decrease the incidence and mortality of atelectasis after thoracotomy in the treatment of lung cancer.
Topics: Female; Humans; Lung Neoplasms; Male; Middle Aged; Pulmonary Atelectasis; Retrospective Studies; Thoracotomy
PubMed: 20673522
DOI: 10.3779/j.issn.1009-3419.2010.03.09 -
British Journal of Anaesthesia Apr 1991We have studied the effects of anaesthesia on atelectasis formation and gas exchange in 45 patients of both sexes, smokers and nonsmokers, aged 23-69 yr. None of the...
We have studied the effects of anaesthesia on atelectasis formation and gas exchange in 45 patients of both sexes, smokers and nonsmokers, aged 23-69 yr. None of the patients showed clinical signs of pulmonary disease, and preoperative spirometry was normal. In the awake patient, partial pressure of arterial oxygen (PaO2) decreased with increasing age (P less than 0.001) and the alveolar-arterial oxygen partial pressure difference (PAO2-PaO2) increased with age (P less than 0.001). Shunt, assessed by the multiple inert gas elimination technique, was small (mean 0.5%) and uninfluenced by age. However, there was an increasing dispersion (log SD Q) of ventilation/perfusion ratios (VA/Q) and increasing perfusion of regions of low VA/Q (VA/Q less than 0.1) with increasing age (P less than 0.001 and P less than 0.05, respectively). No patient displayed any atelectasis as assessed by computed x-ray tomography of the chest. During inhalation anaesthesia (halothane or enflurane) with mechanical ventilation, 39 of 45 patients developed atelectasis and shunt. There was a strong correlation between the atelectatic area and the magnitude of shunt (r = 0.81, P less than 0.001). Atelectasis and shunt did not increase significantly with age, whereas log SD Q and perfusion of regions with low VA/Q ratios did (r = 0.55, P less than 0.001 and r = 0.35, P less than 0.05, respectively). Awake, the major determinant of PaO2 was perfusion of regions of low VA/Q ratios, which increased with age. During anaesthesia shunt influenced PaO2 most, low VA/Q being a secondary factor which, however, was increasingly important with increasing age, thus explaining the well-known age-dependent deterioration of arterial oxygenation during anaesthesia.
Topics: Adult; Age Factors; Aged; Anesthesia, General; Anesthesia, Inhalation; Blood Pressure; Cardiac Output; Enflurane; Female; Halothane; Humans; Lung; Male; Middle Aged; Partial Pressure; Pulmonary Atelectasis; Pulmonary Gas Exchange; Regression Analysis; Tomography, X-Ray Computed; Ventilation-Perfusion Ratio
PubMed: 2025468
DOI: 10.1093/bja/66.4.423 -
Frontiers in Immunology 2022New ventilation modes have been proposed to support the perioperative treatment of patients with obesity, but there is a lack of consensus regarding the optimal... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
New ventilation modes have been proposed to support the perioperative treatment of patients with obesity, but there is a lack of consensus regarding the optimal strategy. Therefore, a network meta-analysis update of 13 ventilation strategies was conducted to determine the optimal mode of mechanical ventilation as a protective ventilation strategy decreases pulmonary atelectasis caused by inflammation.
METHODS
The following databases were searched: MEDLINE; Cochrane Library; Embase; CINAHL; Google Scholar; and Web of Science for randomized controlled trials of mechanical ventilation in patients with obesity published up to May 1, 2022.
RESULTS
Volume-controlled ventilation with individualized positive end-expiratory pressure and a recruitment maneuver (VCV+PEEPind+RM) was found to be the most effective strategy for improving ratio of the arterial O partial pressure to the inspiratory O concentration (PaO/FiO), and superior to pressure-controlled ventilation (PCV), volume-controlled ventilation (VCV), volume-controlled ventilation with recruitment maneuver (VCV+RM), volume-controlled ventilation with low positive end-expiratory pressure (VCV+lowPEEP), volume-controlled ventilation with lower positive expiratory end pressure (PEEP) and recruitment maneuver (VCV+lowPEEP+RM), and the mean difference [MD], the 95% confidence intervals [CIs] and [quality of evidence] were: 162.19 [32.94, 291.45] [very low]; 180.74 [59.22, 302.27] [low]; 171.07 [40.60, 301.54] [very low]; 135.14 [36.10, 234.18] [low]; and 139.21 [27.08, 251.34] [very low]. Surface under the cumulative ranking curve (SUCRA) value showed VCV+PEEPind+RM was the best strategy for improving PaO/FiO (SUCRA: 0.963). VCV with high positive PEEP and recruitment maneuver (VCV+highPEEP+RM) was more effective in decreasing postoperative pulmonary atelectasis than the VCV+lowPEEP+RM strategy. It was found that volume-controlled ventilation with high positive expiratory end pressure (VCV+highPEEP), risk ratio [RR] [95% CIs] and [quality of evidence], 0.56 [0.38, 0.81] [moderate], 0.56 [0.34, 0.92] [moderate]. SUCRA value ranked VCV+highPEEP+RM the best strategy for improving postoperative pulmonary atelectasis intervention (SUCRA: 0.933). It should be noted that the quality of evidence was in all cases very low or only moderate.
CONCLUSIONS
This research suggests that VCV+PEEPind+RM is the optimal ventilation strategy for patients with obesity and is more effective in increasing PaO/FiO, improving lung compliance, and among the five ventilation strategies for postoperative atelectasis, VCV+highPEEP+RM had the greatest potential to reduce atelectasis caused by inflammation.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42021288941.
Topics: Humans; Network Meta-Analysis; Lung; Pulmonary Atelectasis; Obesity; Inflammation
PubMed: 36330511
DOI: 10.3389/fimmu.2022.1032783