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Critical Care (London, England) May 2024Tidal expiratory flow limitation (EFL) complicates the delivery of mechanical ventilation but is only diagnosed by performing specific manoeuvres. Instantaneous analysis...
BACKGROUND
Tidal expiratory flow limitation (EFL) complicates the delivery of mechanical ventilation but is only diagnosed by performing specific manoeuvres. Instantaneous analysis of expiratory resistance (Rex) can be an alternative way to detect EFL without changing ventilatory settings. This study aimed to determine the agreement of EFL detection by Rex analysis and the PEEP reduction manoeuvre using contingency table and agreement coefficient. The patterns of Rex were explored.
METHODS
Medical patients ≥ 15-year-old receiving mechanical ventilation underwent a PEEP reduction manoeuvre from 5 cmHO to zero for EFL detection. Waveforms were recorded and analyzed off-line. The instantaneous Rex was calculated and was plotted against the volume axis, overlapped by the flow-volume loop for inspection. Lung mechanics, characteristics of the patients, and clinical outcomes were collected. The result of the Rex method was validated using a separate independent dataset.
RESULTS
339 patients initially enrolled and underwent a PEEP reduction. The prevalence of EFL was 16.5%. EFL patients had higher adjusted hospital mortality than non-EFL cases. The Rex method showed 20% prevalence of EFL and the result was 90.3% in agreement with PEEP reduction manoeuvre. In the validation dataset, the Rex method had resulted in 91.4% agreement. Three patterns of Rex were identified: no EFL, early EFL, associated with airway disease, and late EFL, associated with non-airway diseases, including obesity. In early EFL, external PEEP was less likely to eliminate EFL.
CONCLUSIONS
The Rex method shows an excellent agreement with the PEEP reduction manoeuvre and allows real-time detection of EFL. Two subtypes of EFL are identified by Rex analysis.
TRIAL REGISTRATION
Clinical trial registered with www.thaiclinicaltrials.org (TCTR20190318003). The registration date was on 18 March 2019, and the first subject enrollment was performed on 26 March 2019.
Topics: Humans; Male; Female; Respiration, Artificial; Middle Aged; Aged; Tidal Volume; Positive-Pressure Respiration; Exhalation; Adult
PubMed: 38773629
DOI: 10.1186/s13054-024-04953-9 -
BMC Pulmonary Medicine May 2024Assessing mechanical properties of the respiratory system (C) during mechanical ventilation necessitates an end-inspiration flow of zero, which requires an...
BACKGROUND
Assessing mechanical properties of the respiratory system (C) during mechanical ventilation necessitates an end-inspiration flow of zero, which requires an end-inspiratory occlusion maneuver. This lung model study aimed to observe the effect of airflow obstruction on the accuracy of respiratory mechanical properties during pressure-controlled ventilation (PCV) by analyzing dynamic signals.
METHODS
A Hamilton C3 ventilator was attached to a lung simulator that mimics lung mechanics in healthy, acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD) models. PCV and volume-controlled ventilation (VCV) were applied with tidal volume (V) values of 5.0, 7.0, and 10.0 ml/kg. Performance characteristics and respiratory mechanics were assessed and were calibrated by virtual extrapolation using expiratory time constant (RC).
RESULTS
During PCV ventilation, drive pressure (DP) was significantly increased in the ARDS model. Peak inspiratory flow (PIF) and peak expiratory flow (PEF) gradually declined with increasing severity of airflow obstruction, while DP, end-inspiration flow (EIF), and inspiratory cycling ratio (EIF/PIF%) increased. Similar estimated values of C and airway resistance (R) during PCV and VCV ventilation were obtained in healthy adult and mild obstructive models, and the calculated errors did not exceed 5%. An underestimation of C and an overestimation of R were observed in the severe obstruction model.
CONCLUSION
Using the modified dynamic signal analysis approach, respiratory system properties (C and R) could be accurately estimated in patients with non-severe airflow obstruction in the PCV mode.
Topics: Humans; Airway Resistance; Pulmonary Disease, Chronic Obstructive; Respiration, Artificial; Respiratory Distress Syndrome; Tidal Volume; Respiratory Mechanics; Lung; Lung Compliance; Models, Biological; Adult
PubMed: 38769572
DOI: 10.1186/s12890-024-03061-2 -
Indian Journal of Anaesthesia May 2024In patients undergoing cancer surgeries with anticipated difficult airway, awake fibreoptic nasotracheal intubation (AFONI) is critical for securing the airway. However,...
Evaluation of different doses of dexmedetomidine for awake fibreoptic nasotracheal intubation in patients undergoing oromaxillofacial and oral malignancy surgeries: A randomised, double-blind study.
BACKGROUND AND AIMS
In patients undergoing cancer surgeries with anticipated difficult airway, awake fibreoptic nasotracheal intubation (AFONI) is critical for securing the airway. However, different doses of dexmedetomidine (DEX) are yet to be evaluated in these patients. Thus, we compared three doses of DEX for AFONI in patients undergoing oromaxillofacial and oral malignancy surgeries.
METHODS
In this randomised, double-blind study, 90 patients aged 18-60 years of either gender, with American Society of Anesthesiologists physical status I/II, and undergoing elective oromaxillofacial and oral malignancy surgeries were randomised to three groups: Group D1 (0.5 µg/kg DEX), Group D2 (1 µg/kg DEX), and Group D3 (1.5 µg/kg DEX). The primary outcome measure was the airway obstruction score. Secondary outcome measures were intubation scores (including vocal movement, coughing, and limb movements) and a 5-point fibreoptic intubation comfort score. Sedation was assessed using the Ramsay sedation score (RSS). One-way ANOVA and Chi-square test were used to assess the association between quantitative and qualitative variables, respectively. A value of <0.05 was considered statistically significant.
RESULTS
The airway obstruction score was comparable between the groups ( = 0.78). Similarly, vocal movement ( = 0.15), coughing ( = 0.31), limb movement ( = 0.51), and 5-point fibreoptic intubation comfort score ( = 0.49) did not differ between the groups. The mean RSS was significantly greater in Group D3 than in Groups D1 and D2 ( = 0.001).
CONCLUSIONS
In combination with topical spray and airway block, all three doses of DEX resulted in comparable airway obstruction scores and thus provided favourable conditions for AFONI.
PubMed: 38764966
DOI: 10.4103/ija.ija_1004_23 -
Asian Journal of Surgery May 2024
PubMed: 38763828
DOI: 10.1016/j.asjsur.2024.05.069 -
International Journal of Surgery Case... Jun 2024Perioperative anesthetic management in cases of severe airway obstruction with positional symptoms can be associated with difficulties in ventilation or intubation, with...
INTRODUCTION AND IMPORTANCE
Perioperative anesthetic management in cases of severe airway obstruction with positional symptoms can be associated with difficulties in ventilation or intubation, with a risk of acute respiratory decompensation at every stage of anesthesia.
CASE PRESENTATION
Here we describe the anesthetic management of an 18-year-old woman with a mature teratoma who presented with progressive exertional dyspnea that was aggravated in the supine position in the operating room. After tracheal intubation, the tidal volume decreased, airway pressure increased, and pet CO2 grew beyond 105 mmHg without oxygen desaturation, prompting a femoro-femoral cardio-pulmonary bypass.
CLINICAL DISCUSSION
Cardio-pulmonary bypass (CPB) can facilitate tumor dissection by safely deflating the lungs and retracting the heart, enhancing exposure and reducing risks of hemodynamic or respiratory complications. However, systemic heparinization may increase complications, necessitating a preoperative risk assessment.
CONCLUSION
Preoperative management of large mediastinal masses requires careful attention to tumor anatomical details and relationships with surrounding structures. Preoperative preparation includes multimodality imaging and multidisciplinary team discussions to assess MMS risk, requiring specialized center management.
PubMed: 38759398
DOI: 10.1016/j.ijscr.2024.109575 -
Journal of Medical Case Reports May 2024Cervical teratomas are rare congenital neoplasms that can cause neonatal airway obstruction if large.
INTRODUCTION
Cervical teratomas are rare congenital neoplasms that can cause neonatal airway obstruction if large.
CASE PRESENTATION
The female Persian neonate displayed respiratory distress at birth, with a 7 cm × 8 cm cystic solid mass identified on the left side of the neck. Antenatal ultrasonography revealed polyhydramnios. Despite initial stabilization, the infant required intubation and mechanical ventilation due to persistent respiratory distress. Imaging confirmed a cystic mass compressing the trachea, ruling out cystic hygroma. Surgical resection on postnatal day 17 revealed a 10 cm × 10 cm solid cystic structure, histologically identified as an immature teratoma.
CONCLUSION
Despite risks of poor fetal and postnatal outcome from large cervical teratomas, early surgical resection after airway stabilization can result in recovery. Proper multidisciplinary management of respiratory distress from such tumors is paramount.
Topics: Humans; Teratoma; Female; Infant, Newborn; Pregnancy; Ultrasonography, Prenatal; Head and Neck Neoplasms; Airway Obstruction; Polyhydramnios
PubMed: 38755694
DOI: 10.1186/s13256-024-04535-x -
Microbiology Spectrum Jun 2024Malignant central airway stenosis is treated with airway stent placement, but post-placement microbial characteristics remain unclear. We studied microbial features in...
UNLABELLED
Malignant central airway stenosis is treated with airway stent placement, but post-placement microbial characteristics remain unclear. We studied microbial features in 60 patients post-stent placement, focusing on changes during granulation tissue proliferation. Samples were collected before stent ( = 29), after stent on day 3 ( = 20), and after granulation tissue formation (AS-GTF, = 43). Metagenomic sequencing showed significant respiratory tract microbiota changes with granulation tissue. The microbiota composition, dominated by , , and , was similar among the groups. At the species level, the AS-GTF group exhibited significant differences, with and enriched. Analysis based on tracheoesophageal fistula presence identified and as the main differential species, enriched in the fistula subgroup. Viral and fungal detection showed and as the main species, respectively. These findings highlight microbiota changes after stent placement, potentially associated with granulation tissue proliferation, informing stent placement therapy and anti-infective treatment optimization.
IMPORTANCE
Malignant central airway stenosis is a life-threatening condition that can be effectively treated with airway stent placement. However, despite its clinical importance, the microbial characteristics of the respiratory tract following stent insertion remain poorly understood. This study addresses this gap by investigating the microbial features in patients with malignant central airway stenosis after stent placement, with a specific focus on microbial changes during granulation tissue proliferation. The findings reveal significant alterations in the diversity and structure of the respiratory tract microbiota following the placement of malignant central airway stents. Notably, certain bacterial species, including and , exhibit distinct patterns in the after-stent granulation tissue formation group. Additionally, the presence of tracheoesophageal fistula further influences the microbial composition. These insights provide valuable references for optimizing stent placement therapy and enhancing clinical anti-infective strategies.
Topics: Humans; Stents; Female; Male; Microbiota; Middle Aged; Aged; Bacteria; Airway Obstruction; Respiratory System; Granulation Tissue; Adult; Aged, 80 and over; Tracheoesophageal Fistula
PubMed: 38747599
DOI: 10.1128/spectrum.03472-23 -
Respiratory Medicine Case Reports 2024Bronchiolitis obliterans (BO) is a form of graft-versus-host disease (GVHD) in the lung and manifests as moderate to severe airflow obstruction after hematopoietic stem...
Bronchiolitis obliterans (BO) is a form of graft-versus-host disease (GVHD) in the lung and manifests as moderate to severe airflow obstruction after hematopoietic stem cell transplantation (HCT). New-onset airflow obstruction on spirometry is considered diagnostic of bronchiolitis obliterans syndrome (BOS). BOS affects about 5% of all HCT recipients. In general, BO is thought of as a late complication of HCT, usually occurring after day 100 post-transplantation. However, the onset of airflow obstruction can be rapid and is most often irreversible even with treatment. We describe a patient who rapidly developed severe airflow obstruction less than one month after transplantation following the development of upper airway symptoms. Despite aggressive immunosuppression, the patient had no improvement in airflow obstruction. We hypothesize that early screening and treatment may help prevent BOS after HCT.
PubMed: 38745870
DOI: 10.1016/j.rmcr.2024.102001 -
Computers in Biology and Medicine Jun 2024Deviations of the septal wall are widespread anatomic anomalies of the human nose; they vary significantly in shape and location, and often cause the obstruction of the...
Deviations of the septal wall are widespread anatomic anomalies of the human nose; they vary significantly in shape and location, and often cause the obstruction of the nasal airways. When severe, septal deviations need to be surgically corrected by ear-nose-throat (ENT) specialists. Septoplasty, however, has a low success rate, owing to the lack of suitable standardized clinical tools for assessing type and severity of obstructions, and for surgery planning. Moreover, the restoration of a perfectly straight septal wall is often impossible and possibly unnecessary. This paper introduces a procedure, based on advanced patient-specific Computational Fluid Dynamics (CFD) simulations, to support ENT surgeons in septoplasty planning. The method hinges upon the theory of adjoint-based optimization, and minimizes a cost function that indirectly accounts for viscous losses. A sensitivity map is computed on the mucosal wall to provide the surgeon with a simple quantification of how much tissue removal at each location would contribute to easing the obstruction. The optimization procedure is applied to three representative nasal anatomies, reconstructed from CT scans of patients affected by complex septal deviations. The computed sensitivity consistently identifies all the anomalies correctly. Virtual surgery, i.e. morphing of the anatomies according to the computed sensitivity, confirms that the characteristics of the nasal airflow improve significantly after small anatomy changes derived from adjoint-based optimization.
Topics: Humans; Nasal Septum; Tomography, X-Ray Computed; Computer Simulation; Male; Female; Nasal Obstruction; Hydrodynamics
PubMed: 38744016
DOI: 10.1016/j.compbiomed.2024.108566 -
Experimental and Clinical... Apr 2024Posttransplant lymphoproliferative disorder is a life-threatening complication after solid-organ transplants. In adults, recipients of heart transplants have the highest...
Posttransplant lymphoproliferative disorder is a life-threatening complication after solid-organ transplants. In adults, recipients of heart transplants have the highest risk, whereas renal transplant recipients have the lowest risk among all solid-organ transplants. The most common site for posttransplant lymphoproliferative disorders are gastrointestinal tract followed by the graft itself. Airway involvement in posttransplant lymphoproliferative disorder is rarely encountered. We report a case of a 26-year-old renal allograft recipient who presented to the emergency room with airway obstruction necessitating an emergency tracheostomy. Imaging revealed a left tonsillar mass extending into the nasopharynx and retropharyngeal space causing complete oropharyngeal occlusion. Endoscopic biopsy from nasopharyngeal mass showed a diffuse large B-cell lymphoma and was Ebstein-Barr virus positive. Reduction in immunosuppression and treatment with posttransplant lymphoproliferative disorder-1 risk-stratified approach resulted in complete remission.
Topics: Humans; Kidney Transplantation; Adult; Treatment Outcome; Airway Obstruction; Immunosuppressive Agents; Male; Lymphoma, Large B-Cell, Diffuse; Acute Disease; Biopsy; Epstein-Barr Virus Infections; Tracheostomy; Remission Induction; Immunocompromised Host; Nasopharyngeal Neoplasms
PubMed: 38742322
DOI: 10.6002/ect.2024.0061