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1.
Anesthesiology ; 134(6): 887-900, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-33843980

RESUMO

BACKGROUND: General anesthesia may cause atelectasis and deterioration in oxygenation in obese patients. The authors hypothesized that individualized positive end-expiratory pressure (PEEP) improves intraoperative oxygenation and ventilation distribution compared to fixed PEEP. METHODS: This secondary analysis included all obese patients recruited at University Hospital of Leipzig from the multicenter Protective Intraoperative Ventilation with Higher versus Lower Levels of Positive End-Expiratory Pressure in Obese Patients (PROBESE) trial (n = 42) and likewise all obese patients from a local single-center trial (n = 54). Inclusion criteria for both trials were elective laparoscopic abdominal surgery, body mass index greater than or equal to 35 kg/m2, and Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score greater than or equal to 26. Patients were randomized to PEEP of 4 cm H2O (n = 19) or a recruitment maneuver followed by PEEP of 12 cm H2O (n = 21) in the PROBESE study. In the single-center study, they were randomized to PEEP of 5 cm H2O (n = 25) or a recruitment maneuver followed by individualized PEEP (n = 25) determined by electrical impedance tomography. Primary endpoint was Pao2/inspiratory oxygen fraction before extubation and secondary endpoints included intraoperative tidal volume distribution to dependent lung and driving pressure. RESULTS: Ninety patients were evaluated in three groups after combining the two lower PEEP groups. Median individualized PEEP was 18 (interquartile range, 16 to 22; range, 10 to 26) cm H2O. Pao2/inspiratory oxygen fraction before extubation was 515 (individual PEEP), 370 (fixed PEEP of 12 cm H2O), and 305 (fixed PEEP of 4 to 5 cm H2O) mmHg (difference to individualized PEEP, 145; 95% CI, 91 to 200; P < 0.001 for fixed PEEP of 12 cm H2O and 210; 95% CI, 164 to 257; P < 0.001 for fixed PEEP of 4 to 5 cm H2O). Intraoperative tidal volume in the dependent lung areas was 43.9% (individualized PEEP), 25.9% (fixed PEEP of 12 cm H2O) and 26.8% (fixed PEEP of 4 to 5 cm H2O) (difference to individualized PEEP: 18.0%; 95% CI, 8.0 to 20.7; P < 0.001 for fixed PEEP of 12 cm H2O and 17.1%; 95% CI, 10.0 to 20.6; P < 0.001 for fixed PEEP of 4 to 5 cm H2O). Mean intraoperative driving pressure was 9.8 cm H2O (individualized PEEP), 14.4 cm H2O (fixed PEEP of 12 cm H2O), and 18.8 cm H2O (fixed PEEP of 4 to 5 cm H2O), P < 0.001. CONCLUSIONS: This secondary analysis of obese patients undergoing laparoscopic surgery found better oxygenation, lower driving pressures, and redistribution of ventilation toward dependent lung areas measured by electrical impedance tomography using individualized PEEP. The impact on patient outcome remains unclear.


Assuntos
Atelectasia Pulmonar , Respiração Artificial , Humanos , Obesidade , Respiração com Pressão Positiva , Volume de Ventilação Pulmonar
2.
Br J Anaesth ; 125(3): 373-382, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32665059

RESUMO

BACKGROUND: Robot-assisted laparoscopic radical prostatectomy requires general anaesthesia, extreme Trendelenburg positioning and capnoperitoneum. Together these promote impaired pulmonary gas exchange caused by atelectasis and may contribute to postoperative pulmonary complications. In morbidly obese patients, a recruitment manoeuvre (RM) followed by individualised PEEP improves intraoperative oxygenation and end-expiratory lung volume (EELV). We hypothesised that individualised PEEP with initial RM similarly improves intraoperative oxygenation and EELV in non-obese individuals undergoing robot-assisted prostatectomy. METHODS: Forty males (age, 49-76 yr; BMI <30 kg m-2) undergoing prostatectomy received volume-controlled ventilation (tidal volume 8 ml kg-1 predicted body weight). Participants were randomised to either (1) RM followed by individualised PEEP (RM/PEEPIND) optimised using electrical impedance tomography or (2) no RM with 5 cm H2O PEEP. The primary outcome was the ratio of arterial oxygen partial pressure to fractional inspired oxygen (Pao2/Fio2) before the last RM before extubation. Secondary outcomes included regional ventilation distribution and EELV which were measured before, during, and after anaesthesia. The cardiovascular effects of RM/PEEPIND were also assessed. RESULTS: In 20 males randomised to RM/PEEPIND, the median PEEPIND was 14 cm H2O [inter-quartile range, 8-20]. The Pao2/Fio2 was 10.0 kPa higher with RM/PEEPIND before extubation (95% confidence interval [CI], 2.6-17.3 kPa; P=0.001). RM/PEEPIND increased end-expiratory lung volume by 1.49 L (95% CI, 1.09-1.89 L; P<0.001). RM/PEEPIND also improved the regional ventilation of dependent lung regions. Vasopressor and fluid therapy was similar between groups, although 13 patients randomised to RM/PEEPIND required pharmacological therapy for bradycardia. CONCLUSION: In non-obese males, an individualised ventilation strategy improved intraoperative oxygenation, which was associated with higher end-expiratory lung volumes during robot-assisted laparoscopic prostatectomy. CLINICAL TRIAL REGISTRATION: DRKS00004199 (German clinical trials registry).


Assuntos
Impedância Elétrica , Respiração com Pressão Positiva/métodos , Prostatectomia/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
3.
Eur J Anaesthesiol ; 37(12): 1105-1114, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33105246

RESUMO

BACKGROUND: Ultrasound-guided interscalene brachial plexus block (ISB) is used to control pain after shoulder surgery. Though effective, drawbacks include phrenic nerve block and motor block of the hand. The ultrasound-guided anterior approach to perform suprascapular nerve block (SSNB) may provide a good alternative. OBJECTIVE: To compare lung ventilation and diaphragmatic activity on the operated side in ISB and SSNB. DESIGN: Randomised, controlled patient-blinded and assessor-blinded trial. SETTING: Outpatient surgical clinic with recruitment from June 2017 to January 2018. PATIENTS: Fifty-five outpatients scheduled for arthroscopic shoulder surgery were allocated randomly to receive SSNB or ISB. Technical problems with monitoring devices unrelated to the intervention led to exclusion of seven patients. The remaining 48 (n=24 in each group) were followed up for 24 h without drop-outs. INTERVENTIONS: Patients received 10 ml of ropivacaine 1.0% wt/vol for both procedures. OUTCOME MEASURES: Percentage lung ventilation on the operated side was the primary endpoint as assessed with electrical impedance tomography (EIT). Secondary endpoints were hemidiaphragmatic motion on the operated side, pain, opioid use, hand strength and numbness, and patient satisfaction. RESULTS: Before regional anaesthesia, the lung on the operated side contributed a median [IQR] of 50 [42 to 56]% of the total lung ventilation. Postoperatively, it was 40 [3 to 50]% (SSNB) vs. 3 [1 to 13]% (ISB) for an adjusted difference of 23 (95% CI, 13 to 34)%, (P < 0.001). Hemidiaphragmatic motion was 1.90 (95% CI, 1.37 to 2.44 cm), (P < 0.001) lower in the ISB group compared with the SSNB group. Hand strength was 11.2 (95% CI 3.6 to 18.9), (P = 0.0024) kg greater for SSNB and numbness was observed in 0% (SSNB) vs. 46% (ISB) of patients, P < 0.001. Pain was low in the first 6 h after surgery in both groups with slightly, but not significantly, lower values for ISB. No meaningful or significant differences were found for opioid use or patient satisfaction. CONCLUSION: An ultrasound-guided anterior approach to SSNB preserves ipsilateral lung ventilation and phrenic function better than a standard ISB. TRIAL REGISTRATION: drks.de identifier: DRKS00011787.


Assuntos
Bloqueio do Plexo Braquial , Anestésicos Locais , Artroscopia , Impedância Elétrica , Humanos , Pulmão , Dor Pós-Operatória , Ombro , Tomografia , Ultrassonografia de Intervenção
4.
Crit Care Med ; 45(4): 679-686, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28079607

RESUMO

OBJECTIVES: Lung-protective mechanical ventilation aims to prevent alveolar collapse and overdistension, but reliable bedside methods to quantify them are lacking. We propose a quantitative descriptor of the shape of local pressure-volume curves derived from electrical impedance tomography, for computing maps that highlight the presence and location of regions of presumed tidal recruitment (i.e., elastance decrease during inflation, pressure-volume curve with upward curvature) or overdistension (i.e., elastance increase during inflation, downward curvature). DESIGN: Secondary analysis of experimental cohort study. SETTING: University research facility. SUBJECTS: Twelve mechanically ventilated pigs. INTERVENTIONS: After induction of acute respiratory distress syndrome by hydrochloric acid instillation, animals underwent a decremental positive end-expiratory pressure titration (steps of 2 cm H2O starting from ≥ 26 cm H2O). MEASUREMENTS AND MAIN RESULTS: Electrical impedance tomography-derived maps were computed at each positive end-expiratory pressure-titration step, and whole-lung CT taken every second steps. Airway flow and pressure were recorded to compute driving pressure and elastance. Significant correlations between electrical impedance tomography-derived maps and positive end-expiratory pressure indicate that, expectedly, tidal recruitment increases in dependent regions with decreasing positive end-expiratory pressure (p < 0.001) and suggest that overdistension increases both at high and low positive end-expiratory pressures in nondependent regions (p < 0.027), supporting the idea of two different scenarios of overdistension occurrence. Significant correlations with CT measurements were observed: electrical impedance tomography-derived tidal recruitment with poorly aerated regions (r = 0.43; p < 0.001); electrical impedance tomography-derived overdistension with nonaerated regions at lower positive end-expiratory pressures and with hyperaerated regions at higher positive end-expiratory pressures (r ≥ 0.72; p < 0.003). Even for positive end-expiratory pressure levels minimizing global elastance and driving pressure, electrical impedance tomography-derived maps showed nonnegligible regions of presumed overdistension and tidal recruitment. CONCLUSIONS: Electrical impedance tomography-derived maps of pressure-volume curve shapes allow to detect regions in which elastance changes during inflation. This could promote individualized mechanical ventilation by minimizing the probability of local tidal recruitment and/or overdistension. Electrical impedance tomography-derived maps might become clinically feasible and relevant, being simpler than currently available alternative approaches.


Assuntos
Impedância Elétrica , Pulmão/diagnóstico por imagem , Síndrome do Desconforto Respiratório/diagnóstico por imagem , Tomografia , Animais , Modelos Animais de Doenças , Elasticidade , Pulmão/fisiopatologia , Respiração com Pressão Positiva , Pressão , Síndrome do Desconforto Respiratório/fisiopatologia , Síndrome do Desconforto Respiratório/terapia , Suínos
5.
BMC Anesthesiol ; 16: 3, 2016 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-26757894

RESUMO

BACKGROUND: Uncertainty persists regarding the optimal ventilatory strategy in trauma patients developing acute respiratory distress syndrome (ARDS). This work aims to assess the effects of two mechanical ventilation strategies with high positive end-expiratory pressure (PEEP) in experimental ARDS following blunt chest trauma. METHODS: Twenty-six juvenile pigs were anesthetized, tracheotomized and mechanically ventilated. A contusion was applied to the right chest using a bolt-shot device. Ninety minutes after contusion, animals were randomized to two different ventilation modes, applied for 24 h: Twelve pigs received conventional pressure-controlled ventilation with moderately low tidal volumes (VT, 8 ml/kg) and empirically chosen high external PEEP (16 cmH2O) and are referred to as the HP-CMV-group. The other group (n = 14) underwent high-frequency inverse-ratio pressure-controlled ventilation (HFPPV) involving respiratory rate of 65 breaths · min(-1), inspiratory-to-expiratory-ratio 2:1, development of intrinsic PEEP and recruitment maneuvers, compatible with the rationale of the Open Lung Concept. Hemodynamics, gas exchange and respiratory mechanics were monitored during 24 h. Computed tomography and histology were analyzed in subgroups. RESULTS: Comparing changes which occurred from randomization (90 min after chest trauma) over the 24-h treatment period, groups differed statistically significantly (all P values for group effect <0.001, General Linear Model analysis) for the following parameters (values are mean ± SD for randomization vs. 24-h): PaO2 (100% O2) (HFPPV 186 ± 82 vs. 450 ± 59 mmHg; HP-CMV 249 ± 73 vs. 243 ± 81 mmHg), venous admixture (HFPPV 34 ± 9.8 vs. 11.2 ± 3.7%; HP-CMV 33.9 ± 10.5 vs. 21.8 ± 7.2%), PaCO2 (HFPPV 46.9 ± 6.8 vs. 33.1 ± 2.4 mmHg; HP-CMV 46.3 ± 11.9 vs. 59.7 ± 18.3 mmHg) and normally aerated lung mass (HFPPV 42.8 ± 11.8 vs. 74.6 ± 10.0 %; HP-CMV 40.7 ± 8.6 vs. 53.4 ± 11.6%). Improvements occurring after recruitment in the HFPPV-group persisted throughout the study. Peak airway pressure and VT did not differ significantly. HFPPV animals had lower atelectasis and inflammation scores in gravity-dependent lung areas. CONCLUSIONS: In this model of ARDS following unilateral blunt chest trauma, HFPPV ventilation improved respiratory function and fulfilled relevant ventilation endpoints for trauma patients, i.e. restoration of oxygenation and lung aeration while avoiding hypercapnia and respiratory acidosis.


Assuntos
Respiração Artificial/métodos , Síndrome do Desconforto Respiratório/terapia , Mecânica Respiratória/fisiologia , Traumatismos Torácicos/terapia , Ferimentos não Penetrantes/terapia , Animais , Respiração com Pressão Positiva/métodos , Distribuição Aleatória , Síndrome do Desconforto Respiratório/etiologia , Síndrome do Desconforto Respiratório/fisiopatologia , Suínos , Traumatismos Torácicos/complicações , Traumatismos Torácicos/fisiopatologia , Ferimentos não Penetrantes/complicações , Ferimentos não Penetrantes/fisiopatologia
6.
Anaesthesiologie ; 73(8): 502-510, 2024 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-39060458

RESUMO

Small, portable hand-held ultrasound devices nowadays enable a widespread use of prehospital point-of-care ultrasound (pPOCUS), which has so far only been used hesitantly, especially in ground-based emergency services. Many critical or even life-threatening conditions or internal injuries can often be better diagnosed or ruled out using pPOCUS, which can enable faster and more suitable goal-directed treatment and hospital transport. This article critically discusses relevant data, clinical benefits, limitations and challenges to be overcome when using pPOCUS for the most important life-threatening situations and aims to call for intensifying training and the extensive use of pPOCUS.


Assuntos
Serviços Médicos de Emergência , Medicina de Emergência , Sistemas Automatizados de Assistência Junto ao Leito , Ultrassonografia , Humanos , Serviços Médicos de Emergência/métodos , Ultrassonografia/métodos , Ultrassonografia/instrumentação , Medicina de Emergência/educação , Medicina de Emergência/métodos
7.
Crit Care Med ; 41(3): 732-43, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23318487

RESUMO

OBJECTIVES: Studies correlating the arterial partial pressure of oxygen to the fraction of nonaerated lung assessed by CT shunt yielded inconsistent results. We systematically analyzed this relationship and scrutinized key methodological factors that may compromise it. We hypothesized that both physiological shunt and the ratio between PaO2 and the fraction of inspired oxygen enable estimation of CT shunt at the bedside. DESIGN: : Prospective observational clinical and laboratory animal investigations. SETTING: ICUs (University Hospital Leipzig, Germany) and Experimental Pulmonology Laboratory (University of São Paulo, Brazil). PATIENTS, SUBJECTS AND INTERVENTIONS: Whole-lung CT and arterial blood gases were acquired simultaneously in 77 patients mechanically ventilated with pure oxygen. A subgroup of 28 patients was submitted to different Fio2. We also studied 19 patients who underwent repeat CT. Furthermore we studied ten pigs with acute lung injury at multiple airway pressures, as well as a theoretical model relating PaO2 and physiological shunt. We logarithmically transformed the PaO2/Fio2 to change this nonlinear relationship into a linear regression problem. MEASUREMENTS AND MAIN RESULTS: We observed strong linear correlations between Riley's approximation of physiological shunt and CT shunt (R = 0.84) and between logarithmically transformed PaO2/Fio2 and CT shunt (R = 0.86), allowing us to construct a look-up table with prediction intervals. Strong linear correlations were also demonstrated within-patients (R = 0.95). Correlations were significantly improved by the following methodological issues: measurement of PaO2/Fio2 during pure oxygen ventilation, use of logarithmically transformed PaO2/Fio2 instead of the "raw" PaO2/Fio2, quantification of nonaerated lung as percentage of total lung mass and definition of nonaerated lung by the [-200 to +100] Hounsfield Units interval, which includes shunting units within less opacified lung regions. CONCLUSION: During pure oxygen ventilation, logarithmically transformed PaO2/Fio2 allows estimation of CT shunt and its changes in patients during systemic inflammation. Relevant intrapulmonary shunting seems to occur in lung regions with CT numbers between [-200 and +100] Hounsfield Units.


Assuntos
Gasometria/métodos , Pulmão/fisiopatologia , Sistemas Automatizados de Assistência Junto ao Leito , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Brasil , Feminino , Alemanha , Humanos , Unidades de Terapia Intensiva , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Modelos Animais , Estudos Prospectivos , Suínos , Tomografia Computadorizada por Raios X , Adulto Jovem
8.
Int J Comput Assist Radiol Surg ; 17(9): 1707-1716, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35357633

RESUMO

PURPOSE: For the visualization of pulmonary ventilation with Electrical Impedance Tomography (EIT) most devices use standard reconstruction models, featuring common thorax dimensions and predetermined electrode locations. Any discrepancies between the available model and the patient in terms of body shape and electrode position lead to incorrectly displayed impedance distributions. This work addresses that problem by presenting and evaluating a method for 3D model generation of the thorax and any affixed electrodes based on handheld video-footage. METHODS: Therefore, a process was developed, providing users with the ability to capture a patient's chest and the attached electrodes via smartphone. Once data is collected, extracted images are used to generate a 3D model with a structure from motion approach and locate electrodes with ArUco markers. For the evaluation of the developed method, multiple tests were performed in laboratory environments, which were compared with manually created reference models and differences quantified based on mean distance, standard deviation, and maximum distance. RESULTS: The implemented workflow allows for automated model reconstruction based on videos or selected images captured with a handheld device. It generates sparse point clouds from which a surface mesh is reconstructed and returns relative coordinates of any identified ArUco marker. The average value for the mean distance error of two model generations was 5.4 mm while the mean standard deviation was 6.0 mm. The average runtime of twelve reconstructions was 5:17 min, with a minimal runtime of 3:22 min and a maximal runtime of 7:29 min. CONCLUSION: The presented methods and results show that model reconstruction of a patient's thorax and applied electrodes at an emergency site is feasible with already available devices. This is a first step toward the automated generation of patient-specific reconstruction models for Electrical Impedance Tomography based on images recorded with handheld devices.


Assuntos
Tórax , Tomografia , Impedância Elétrica , Eletrodos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Tomografia/métodos , Tomografia Computadorizada por Raios X
10.
Crit Care ; 15(1): R71, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21352529

RESUMO

INTRODUCTION: Quantitative computed tomography (qCT)-based assessment of total lung weight (Mlung) has the potential to differentiate atelectasis from consolidation and could thus provide valuable information for managing trauma patients fulfilling commonly used criteria for acute lung injury (ALI). We hypothesized that qCT would identify atelectasis as a frequent mimic of early posttraumatic ALI. METHODS: In this prospective observational study, Mlung was calculated by qCT in 78 mechanically ventilated trauma patients fulfilling the ALI criteria at admission. A reference interval for Mlung was derived from 74 trauma patients with morphologically and functionally normal lungs (reference). Results are given as medians with interquartile ranges. RESULTS: The ratio of arterial partial pressure of oxygen to the fraction of inspired oxygen was 560 (506 to 616) mmHg in reference patients and 169 (95 to 240) mmHg in ALI patients. The median reference Mlung value was 885 (771 to 973) g, and the reference interval for Mlung was 584 to 1164 g, which matched that of previous reports. Despite the significantly greater median Mlung value (1088 (862 to 1,342) g) in the ALI group, 46 (59%) ALI patients had Mlung values within the reference interval and thus most likely had atelectasis. In only 17 patients (22%), Mlung was increased to the range previously reported for ALI patients and compatible with lung consolidation. Statistically significant differences between atelectasis and consolidation patients were found for age, Lung Injury Score, Glasgow Coma Scale score, total lung volume, mass of the nonaerated lung compartment, ventilator-free days and intensive care unit-free days. CONCLUSIONS: Atelectasis is a frequent cause of early posttraumatic lung dysfunction. Differentiation between atelectasis and consolidation from other causes of lung damage by using qCT may help to identify patients who could benefit from management strategies such as damage control surgery and lung-protective mechanical ventilation that focus on the prevention of pulmonary complications.


Assuntos
Lesão Pulmonar Aguda/diagnóstico por imagem , Lesão Pulmonar Aguda/patologia , Atelectasia Pulmonar/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto , Diagnóstico Diferencial , Feminino , Humanos , Pulmão/anatomia & histologia , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Estudos Prospectivos , Valores de Referência , Respiração Artificial , Adulto Jovem
11.
Crit Care ; 15(6): R279, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22112625

RESUMO

INTRODUCTION: Computed tomography (CT) is considered the gold standard for quantification of global or regional lung aeration and lung mass. Quantitative CT, however, involves the exposure to ionizing radiation and requires manual image processing. We recently evaluated an extrapolation method which calculates quantitative CT parameters characterizing the entire lung from only 10 reference CT-slices thereby reducing radiation exposure and analysis time. We hypothesized that this extrapolation method could be further validated using CT-data from pigs and sheep, which have a different thoracic anatomy. METHODS: We quantified volume and mass of the total lung and differently aerated lung compartments in 168 ovine and 55 porcine whole-lung CTs covering lung conditions from normal to gross deaeration. Extrapolated volume and mass parameters were compared to the respective values obtained by whole-lung analysis. We also tested the accuracy of extrapolation for all possible numbers of CT slices between 15 and 5. Bias and limits of agreement (LOA) were analyzed by the Bland-Altman method. RESULTS: For extrapolation from 10 reference slices, bias (LOA) for the total lung volume and mass of sheep were 18.4 (-57.2 to 94.0) ml and 4.2 (-21.8 to 30.2) grams, respectively. The corresponding bias (LOA) values for pigs were 5.1 (-55.2 to 65.3) ml and 1.6 (-32.9 to 36.2) grams, respectively. All bias values for differently aerated lung compartments were below 1% of the total lung volume or mass and the LOA never exceeded ± 2.5%. Bias values diverged from zero and the LOA became considerably wider when less than 10 reference slices were used. CONCLUSIONS: The extrapolation method appears robust against variations in thoracic anatomy, which further supports its accuracy and potential usefulness for clinical and experimental application of quantitative CT.


Assuntos
Pulmão/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Animais , Pulmão/anatomia & histologia , Pulmão/fisiologia , Tamanho do Órgão , Ovinos , Suínos
13.
PLoS One ; 15(1): e0227518, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31923268

RESUMO

INTRODUCTION: Posttraumatic pneumothorax (PTX) is often overseen in anteroposterior chest X-ray. Chest sonography and Electrical Impedance Tomography (EIT) can both be used at the bedside and may provide complementary information. We evaluated the performance of EIT for diagnosing posttraumatic PTX in a pig model. METHODS: This study used images from an existing database of images acquired from 17 mechanically ventilated pigs, which had sustained standardized blunt chest trauma and had undergone repeated thoracic CT and EIT. 100 corresponding EIT/CT datasets were randomly chosen from the database and anonymized. Two independent and blinded observers analyzed the EIT data for presence and location of PTX. Analysis of the corresponding CTs by a radiologist served as reference. RESULTS: 87/100 cases had at least one PTX detected by CT. Fourty-two cases showed a PTX > 20% of the sternovertebral diameter (PTXtrans20), whereas 52/100 PTX showed a PTX>3 cm in the craniocaudal diameter (PTXcc3), with 20 cases showing both a PTXtranscc and a PTXcc3. We found a very low agreement between both EIT observers considering the classification overall PTX/noPTX (κ = 0.09, p = 0.183). For PTXtrans20, sensitivity was 59% for observer 1 and 17% for observer 2, with a specificity of 48% and 50%, respectively. For PTXcc3, observer 1 showed a sensitivity of 60% with a specificity of 51% while the sensitivity of observer 2 was 17%, with a specificity of 89%. By programming a semi-automatized detection algorithm, we significantly improved the detection rate of PTXcc3, with a sensitivity of 73% and a specificity of 70%. However, detection of PTXtranscc was not improved. CONCLUSION: In our analysis, visual interpretation of EIT without specific image processing or comparison with baseline data did not allow clinically useful diagnosis of posttraumatic PTX. Multimodal imaging approaches, technical improvements and image postprocessing algorithms might improve the performance of EIT for diagnosing PTX in the future.


Assuntos
Impedância Elétrica , Pneumotórax/diagnóstico , Traumatismos Torácicos/patologia , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Animais , Pneumotórax/etiologia , Pneumotórax/veterinária , Respiração Artificial , Suínos , Traumatismos Torácicos/complicações , Traumatismos Torácicos/veterinária , Ultrassonografia , Ferimentos não Penetrantes/complicações , Ferimentos não Penetrantes/patologia , Ferimentos não Penetrantes/veterinária
14.
J Clin Med ; 8(8)2019 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-31426607

RESUMO

Reducing ventilator-associated lung injury by individualized mechanical ventilation (MV) in patients with Acute Respiratory Distress Syndrome (ARDS) remains a matter of research. We randomly assigned 27 pigs with acid aspiration-induced ARDS to three different MV protocols for 24 h, targeting different magnitudes of collapse and tidal recruitment (collapse&TR): the ARDS-network (ARDSnet) group with low positive end-expiratory pressure (PEEP) protocol (permissive collapse&TR); the Open Lung Concept (OLC) group, PaO2/FiO2 >400 mmHg, indicating collapse&TR <10%; and the minimized collapse&TR monitored by Electrical Impedance Tomography (EIT) group, standard deviation of regional ventilation delay, SDRVD. We analyzed cardiorespiratory parameters, computed tomography (CT), EIT, and post-mortem histology. Mean PEEP over post-randomization measurements was significantly lower in the ARDSnet group at 6.8 ± 1.0 cmH2O compared to the EIT (21.1 ± 2.6 cmH2O) and OLC (18.7 ± 3.2 cmH2O) groups (general linear model (GLM) p < 0.001). Collapse&TR and SDRVD, averaged over all post-randomization measurements, were significantly lower in the EIT and OLC groups than in the ARDSnet group (collapse p < 0.001, TR p = 0.006, SDRVD p < 0.004). Global histological diffuse alveolar damage (DAD) scores in the ARDSnet group (10.1 ± 4.3) exceeded those in the EIT (8.4 ± 3.7) and OLC groups (6.3 ± 3.3) (p = 0.16). Sub-scores for edema and inflammation differed significantly (ANOVA p < 0.05). In a clinically realistic model of early ARDS with recruitable and nonrecruitable collapse, mechanical ventilation involving recruitment and high-PEEP reduced collapse&TR and resulted in improved hemodynamic and physiological conditions with a tendency to reduced histologic lung damage.

16.
Intensive Care Med ; 34(11): 2044-53, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18537024

RESUMO

OBJECTIVES: Lung hyperinflation may be assessed by computed tomography (CT). As shown for patients with emphysema, however, CT image reconstruction affects quantification of hyperinflation. We studied the impact of reconstruction parameters on hyperinflation measurements in mechanically ventilated (MV) patients. DESIGN: Observational analysis. SETTING: A University hospital-affiliated research Unit. PATIENTS: The patients were MV patients with injured (n = 5) or normal lungs (n = 6), and spontaneously breathing patients (n = 5). INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Eight image series involving 3, 5, 7, and 10 mm slices and standard and sharp filters were reconstructed from identical CT raw data. Hyperinflated (V(hyper)), normally (V(normal)), poorly (V(poor)), and nonaerated (V(non)) volumes were calculated by densitometry as percentage of total lung volume (V(total)). V(hyper) obtained with the sharp filter systematically exceeded that with the standard filter showing a median (interquartile range) increment of 138 (62-272) ml corresponding to approximately 4% of V(total). In contrast, sharp filtering minimally affected the other subvolumes (V(normal), V(poor), V(non), and V(total)). Decreasing slice thickness also increased V(hyper) significantly. When changing from 10 to 3 mm thickness, V(hyper) increased by a median value of 107 (49-252) ml in parallel with a small and inconsistent increment in V(non) of 12 (7-16) ml. CONCLUSIONS: Reconstruction parameters significantly affect quantitative CT assessment of V(hyper) in MV patients. Our observations suggest that sharp filters are inappropriate for this purpose. Thin slices combined with standard filters and more appropriate thresholds (e.g., -950 HU in normal lungs) might improve the detection of V(hyper). Different studies on V(hyper) can only be compared if identical reconstruction parameters were used.


Assuntos
Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Respiração Artificial , Tomografia Computadorizada Espiral , Adulto , Análise de Variância , Artefatos , Meios de Contraste , Feminino , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Estatísticas não Paramétricas
18.
Reg Anesth Pain Med ; 42(3): 310-318, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28257388

RESUMO

BACKGROUND AND OBJECTIVES: The interscalene brachial plexus block (ISB), a potent option to control pain after shoulder surgery, has notable adverse effects. The anterior suprascapular nerve block (SSNB) might provide comparable analgesia and cause less grip-strength impairment. These characteristics were studied in this randomized controlled patient- and assessor-blinded trial. METHODS: Outpatients were randomized to single-shot ultrasound-guided SSNB (10 mL ropivacaine 1%) or ISB (20 mL ropivacaine 0.75%) before general anesthesia for arthroscopic shoulder surgery. Pain (Numerical Rating Scale, 0-10), grip strength, degree of satisfaction, and strength of recommendation were assessed. RESULTS: We randomized 168 patients to each group and analyzed 164 in the SSNB group and 165 in the ISB group. Nerve blocks were successful in 98% of the patients from each group. Both procedures provided good postoperative analgesia, and the mean pain level for SSNB was slightly but significantly lower by 0.32 units (95% confidence interval, 0.18-0.46; P < 0.001) and noninferior given a margin of 1.1 units; P < 0.001. Within the first 24 hours, 162 (99%) of SSNB patients had unimpaired grip strength compared to 81 (49%) of ISB patients (P < 0.001). The multiple primary outcome, superior unimpaired grip strength, and noninferior pain control was significant; P < 0.001. Compared to ISB patients (n = 130 [79%]), significantly more SSNB patients (n = 150 [91%]) were satisfied/highly satisfied. Patients in the SSNB group were more likely to recommend the procedure highly. CONCLUSIONS: For outpatients undergoing arthroscopic shoulder surgery under general anesthesia, the SSNB seems preferable to ISB. It provides excellent postoperative analgesia without exposing patients to impaired mobility and to risks of the more potent but also more invasive ISB.


Assuntos
Procedimentos Cirúrgicos Ambulatórios/métodos , Artroscopia/métodos , Bloqueio Nervoso Autônomo/métodos , Bloqueio do Plexo Braquial/métodos , Ombro/cirurgia , Adulto , Idoso , Procedimentos Cirúrgicos Ambulatórios/normas , Bloqueio Nervoso Autônomo/normas , Bloqueio do Plexo Braquial/normas , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor Pós-Operatória/diagnóstico por imagem , Dor Pós-Operatória/prevenção & controle , Escápula/diagnóstico por imagem , Escápula/cirurgia , Ombro/diagnóstico por imagem
19.
A A Case Rep ; 6(7): 193-5, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26752177

RESUMO

An 82-year-old man required aortic valve replacement because of aortic stenosis. A transapical approach was chosen to reduce surgical mortality. Initially, echocardiography and fluoroscopy confirmed correct valve positioning. Shortly thereafter, progressive paravalvular leakage, embolization of the valve prosthesis into the ventricle, and subsequent inversion of the prosthesis with complete left ventricular outflow occlusion were observed by echocardiography. Left ventricular outflow occlusion resulted in immediate circulatory arrest. We immediately converted to on-pump surgical aortic valve replacement. Cardiac output was restored once the valve was replaced. The patient fully recovered. This case report highlights the importance of periprocedural transesophageal echocardiography, which instantly detected the malpositioned valve and guided emergency management of this severe complication.


Assuntos
Implante de Prótese de Valva Cardíaca/métodos , Obstrução do Fluxo Ventricular Externo/diagnóstico por imagem , Obstrução do Fluxo Ventricular Externo/cirurgia , Idoso de 80 Anos ou mais , Ecocardiografia Transesofagiana/métodos , Próteses Valvulares Cardíacas , Implante de Prótese de Valva Cardíaca/instrumentação , Humanos , Masculino , Resultado do Tratamento , Obstrução do Fluxo Ventricular Externo/etiologia
20.
Artigo em Inglês | MEDLINE | ID: mdl-26504733

RESUMO

Peripheral nerve catheters are effective and well-established tools to provide postoperative analgesia to patients undergoing orthopedic surgery. The performance of these techniques is usually considered safe. However, placement of nerve catheters may be associated with a considerable number of side effects and major complications have repeatedly been published. In this work, we report on a patient who underwent total knee replacement with spinal anesthesia and preoperative insertion of femoral and sciatic nerve catheters for postoperative analgesia. During insertion of the femoral catheter, significant resistance was encountered upon retracting the catheter. This occurred due to knotting of the catheter. The catheter had to be removed by operative intervention which has to be considered a major complication. The postoperative course was uneventful. The principles for removal of entrapped peripheral catheters are not well established, may differ from those for neuroaxial catheters, and range from cautious manipulation up to surgical intervention.

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