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End-tidal CO2

Yu Onodera, Ryo Akimoto, Hiroto Suzuki, Masayuki Okada, Masaki Nakane, Kaneyuki Kawamae
BACKGROUND: Although clinical studies of the high-flow nasal cannula (HFNC) and its effect on positive end-expiratory pressure (PEEP) have been done, the washout effect has not been well evaluated. Therefore, we made an experimental respiratory model to evaluate the respiratory physiological effect of HFNC. METHODS: An airway model was made by a 3D printer using the craniocervical 3D-CT data of a healthy 32-year-old male. CO2 was infused into four respiratory lung models (normal-lung, open- and closed-mouth models; restrictive- and obstructive-lung, open-mouth models) to maintain the partial pressure of end-tidal CO2 (PET CO2 ) at 40 mmHg...
March 15, 2018: Intensive Care Medicine Experimental
Maria Sole Morelli, Alberto Greco, Gaetano Valenza, Alberto Giannoni, Michele Emdin, Enzo Pasquale Scilingo, Nicola Vanello
Brain activations related to the control of breathing are not completely known. The respiratory system is a non-linear system. However, the relationship between neural and respiratory dynamics is usually estimated through linear correlation measures, completely neglecting possible underlying nonlinear interactions. This study evaluate the linear and nonlinear coupling between electroencephalographic (EEG) signal and variations in carbon dioxide (CO2 ) signal related to different breathing task. During a free breathing and a voluntary breath hold tasks, the coupling between EEG power in nine different brain regions in delta (1-3 Hz) and alpha (8-13 Hz) bands and end-tidal CO2 (PET CO2 ) was evaluated...
March 14, 2018: Scientific Reports
James R Sackett, Zachary J Schlader, Morgan C O'Leary, Christopher L Chapman, Blair D Johnson
NEW FINDINGS: What is the central question of the study? Is central chemosensitivity blunted during thermoneutral head out water immersion in healthy humans? What is the main finding and its importance? Central chemosensitivity is augmented during thermoneutral head out water immersion in healthy men and women. Thus, we suggest that the central chemoreceptors do not contribute CO2 retention during head out water immersion. ABSTRACT: Carbon dioxide (CO2 ) retention occurs during water immersion...
March 12, 2018: Experimental Physiology
Baraa K Al-Khazraji, Leena N Shoemaker, Joseph S Gati, Trevor Szekeres, J Kevin Shoemaker
The larger intracranial conduit vessels contribute to the total cerebral vascular resistance, and understanding their vasoreactivity to physiological stimuli is required when attempting to understand regional brain perfusion. Reactivity of the larger cerebral conduit arteries remains understudied due to a need for improved imaging methods to simultaneously assess these vessels in a single stimulus. We characterized reactivity of basal intracranial conduit arteries (basilar, right and left posterior, middle and anterior cerebral arteries) and the right and left internal carotid arteries, to manipulations in end-tidal CO2 (PetCO2 )...
January 1, 2018: Journal of Cerebral Blood Flow and Metabolism
Tadayoshi Miyamoto, Kou Manabe, Shinya Ueda, Hidehiro Nakahara
NEW FINDINGS: What is the central question of this study? The lack of useful small animal models for studying exercise hyperpnoea makes it difficult to investigate the underlying mechanisms of exercise-induced ventilatory abnormalities in various disease states. What is the main finding and its importance? We developed an anesthetized rat model for studying exercise hyperpnoea, using respiratory equilibrium diagram for quantitative characterization of the respiratory chemoreflex feedback system...
March 6, 2018: Experimental Physiology
Denise C Mannée, Timon M Fabius, Michiel Wagenaar, Michiel M M Eijsvogel, Frans H C de Jongh
In this study, the hypercapnic ventilatory response (HCVR) was measured, defined as the ventilation response to carbon dioxide tension ( P CO2 ). We investigated which method, rebreathing or steady-state, is most suitable for measurement of the HCVR in healthy subjects, primarily based on reproducibility. Secondary outcome parameters were subject experience and duration. 20 healthy adults performed a rebreathing and steady-state HCVR measurement on two separate days. Subject experience was assessed using numeric rating scales (NRS)...
January 2018: ERJ Open Research
Yi-Ming Zeng, Yun-Feng Chen, Hui-Huang Lin, Xiao-Bin Zhang
BACKGROUND: Location of the affected bronchus of pleural air leaks is the most important step of trans-bronchoscopic bronchial occlusion for the treatment of intractable pneumothorax. The balloon occlusion test is the most commonly used technique, but has failed in some cases. The aim of the present study was: (1) to determine if endo-bronchial end-tidal CO2 (EtCO2 ) measurement can identify the affected bronchus that is the source of a persistent pleural air leak; and (2) to establish a methodology for endo-bronchial EtCO2 testing in locating affected bronchus in intractable pneumothorax...
January 2018: Therapeutic Advances in Respiratory Disease
Daniel A Keir, Michael Pollock, Piramilan Thuraisingam, Donald H Paterson, George J F Heigenhauser, Harry B Rossiter, John M Kowalchuk
We examined whether slower pulmonary O2 uptake (V̇O2p ) kinetics in hypoxia is a consequence of: a) hypoxia alone (lowered arterial O2 pressure), b) hyperventilation-induced hypocapnia (lowered arterial CO2 pressure), or c) a combination of both. Eleven participants performed 3-5 repetitions of step-changes in cycle ergometer power output from 20W to 80% lactate threshold in the following conditions: i) normoxia (CON; room air); ii) hypoxia (HX, inspired O2  = 12%; lowered end-tidal O2 pressure [PET O2 ] and end-tidal CO2 pressure [PET CO2 ]); iii) hyperventilation (HV; increased PET O2 and lowered PET CO2 ); and iv) normocapnic hypoxia (NC-HX; lowered PET O2 and PET CO2 matched to CON)...
February 22, 2018: Respiratory Physiology & Neurobiology
John B West, Daniel R Crouch, Janelle M Fine, Dipen Makadia, Daniel L Wang, G Kim Prisk
BACKGROUND: It would be valuable to have a noninvasive method of measuring impaired pulmonary gas exchange in patients with lung disease and so reduce the need for repeated arterial punctures. Here we report the results of using a new test in a group of outpatients attending a pulmonary clinic. METHODS: Inspired and expired P O2 and P CO2 are continually measured by small, rapidly responding analyzers. The arterial P O2 is calculated from the oximeter Sp O2 and the oxygen dissociation curve...
February 13, 2018: Chest
Linda Lakdawala, Bryce Dickey, Mohammad Alrawashdeh
PURPOSE: Obstructive sleep apnea (OSA) increases the risk of respiratory depression in surgical patients. This project screened patients for OSA and explored its relationship with respiratory complications. DESIGN: Quality improvement project. METHODS: Neurosurgical patients were preoperatively screened using STOP-Bang questionnaire scores of 5 or greater as high risk and less than 5 as low risk for moderate-to-severe OSA. Postoperative respiratory complications were compared between both OSA groups...
February 8, 2018: Journal of Perianesthesia Nursing: Official Journal of the American Society of PeriAnesthesia Nurses
Philip J Peyton, Monique Kozub
Technologies for minimally-invasive cardiac output measurement in patients during surgery remain little used in routine practice. We tested a redeveloped system based on CO 2 elimination (VCO 2 ) by the lungs for use in ventilated patients, which can be seamlessly integrated into a modern anesthesia/monitoring platform, and provides automated, continuous breath-by-breath cardiac output monitoring. A prototype measurement system was constructed to measure VCO 2 and end-tidal CO 2 concentration with each breath...
February 8, 2018: Journal of Clinical Monitoring and Computing
W Alan C Mutch, Michael J Ellis, Lawrence N Ryner, Patrick J McDonald, Marc P Morissette, Philip Pries, Marco Essig, David J Mikulis, James Duffin, Joseph A Fisher
Background: Preliminary studies suggest that sports-related concussion (SRC) is associated with alterations in cerebral blood flow (CBF) regulation. Here, we use advanced magnetic resonance imaging (MRI) techniques to measure CBF and cerebrovascular responsiveness (CVR) in individual SRC patients and healthy control subjects. Methods: 15 SRC patients (mean age = 16.3, range 14-20 years) and 27 healthy control subjects (mean age = 17.6, range 13-21 years) underwent anatomical MRI, pseudo-continuous arterial spin labeling (pCASL) MRI and model-based prospective end-tidal targeting (MPET) of CO2 during blood oxygenation level-dependent (BOLD) MRI...
2018: Frontiers in Neurology
Fernando Calado de Oliveira Camacho, Tânia Marina Lopes Amaral, Joana Irene de Barros Mourão
Schwartz-Jampel syndrome (SJS) is a rare genetic condition that is characterized by several musculoskeletal abnormalities, such as myotonia, joint contractures, and facial dysmorphisms. Patients with this syndrome can present an anesthetic challenge, due to an increased risk of developing malignant hyperthermia (MH) and the possibility of encountering a difficult airway. Several precautions must be taken when general anesthesia is required, such as the avoidance of potential triggers for MH, continuous core temperature, and end-tidal CO2 monitoring, assuring that dantrolene is readily available...
January 2018: Saudi Journal of Anaesthesia
Tian-Xiang Chen, Bigyan Pudasaini, Jian Guo, Su-Gang Gong, Rong Jiang, Lan Wang, Qin-Hua Zhao, Wen-Hui Wu, Ping Yuan, Jin-Ming Liu
Background: Sex differences in chronic thromboembolic pulmonary hypertension (CTEPH) have been revealed in few studies. Although right heart catheterization (RHC) is the gold standard for clinical diagnosis and assessment of prognosis in pulmonary hypertension (PH), cardiopulmonary exercise testing (CPET) has been a more widely used assessment of functional capacity, disease severity, prognosis, and treatment response in PH. We hypothesized that the "sex-specific" CPET indices could estimate the severity of inoperable CTEPH...
2018: International Journal of Chronic Obstructive Pulmonary Disease
K Terziyski, A Draganova
Characterized by periodic crescendo-decrescendo pattern of breathing alternating with central apneas, Central sleep apnea (CSA) with Cheyne-Stokes Breathing represents a highly prevalent, yet underdiagnosed comorbidity in chronic heart failure (CHF). A diverse body of evidence demonstrates increased morbidity and mortality in the presence of CSB. CSB has been described in both CHF patients with preserved and reduced ejection fraction, regardless of drug treatment. Risk factors for CSB are older age, male gender, high BMI, atrial fibrillation and hypocapnia...
February 7, 2018: Advances in Experimental Medicine and Biology
Lennart Geurts, Alex Bhogal, Jeroen Siero, Peter Luijten, Geert Jan Biessels, Jaco Zwanenburg
Existing cerebrovascular reactivity (CVR) techniques assess flow reactivity in either the largest cerebral vessels or at the level of the parenchyma. We examined the ability of 2D phase contrast MRI at 7 T to measure CVR in small cerebral perforating arteries. Blood flow velocity in perforators was measured in 10 healthy volunteers (mean age 26 years) using a 7 T MR scanner, using phase contrast acquisitions in the semioval center (CSO), the basal ganglia (BG) and the middle cerebral artery (MCA). Changes in flow velocity in response to a hypercapnic breathing challenge were assessed, and expressed as the percentual increase of flow velocity as a function of the increase in end tidal partial pressure of CO2...
February 2, 2018: NeuroImage
Sheila Fraser, Olov Norlén, Kyle Bender, Joanne Davidson, Sonya Bajenov, David Fahey, Shawn Li, Stan Sidhu, Mark Sywak
BACKGROUND: Posterior retroperitoneoscopic adrenalectomy has gained widespread acceptance for the removal of benign adrenal tumors. Higher insufflation pressures using carbon dioxide (CO2 ) are required, although the ideal starting pressure is unclear. This prospective, randomized, single-blinded, study aims to compare physiologic differences with 2 different CO2 insufflation pressures during posterior retroperitoneoscopic adrenalectomy. METHODS: Participants were randomly assigned to a starting insufflation pressure of 20 mm Hg (low pressure) or 25 mm Hg (high pressure)...
January 30, 2018: Surgery
Leila Mashhadi, Alireza Sabzevari, Mohammad Gharavi Fard, Reza Shojaeian, Maryam Salehi, Marjan Joodi, Mahdi Fathi, Ali Jafarzadeh Esfehani, Kamran Khazaeni
Introduction: Tracheobronchial foreign body aspiration is a common life-threatening condition in children. There are controversies in the management of this condition, including the type of ventilation during bronchoscopy. This study aims to compare anesthesia with controlled ventilation versus spontaneous ventilation in rigid bronchoscopy in children with foreign body aspiration. Materials and Methods: Patients who were candidates for rigid bronchoscopy due to foreign body aspiration were randomly assigned to either anesthesia with spontaneous ventilation or controlled ventilation...
November 2017: Iranian Journal of Otorhinolaryngology
Mosaad Abdel-Aziz, Ayman Hussien, Ahmed Kamel, Khaled Azooz, Mohamed Fawaz
Velopharyngeal surgical procedures may have adverse effect on the airway of the patients with velopharyngeal insufficiency (VPI). The aim of this study was to evaluate the polysomnographic parameters (PSG) in patients who underwent corrective surgery for treatment of VPI. The study included 39 patients who underwent 1 of 3 velopharyngeal surgical techniques; Furlow palatoplasty (12 patients), pharyngeal flap (18 patients), and sphincter pharyngoplasty (9 patients). The patients were subjected to PSG, and they were considered to have obstructive sleep apnea (OSA) with apnea-hypoapnea index (AHI) >1...
January 29, 2018: Journal of Craniofacial Surgery
Hagen Bomberg, Max Veddeler, Thomas Volk, Heinrich V Groesdonk, Andreas Meiser
Inhalation sedation is increasingly performed in intensive care units. For this purpose, two anaesthetic reflectors, AnaConDa™ and Mirus™ are commercially available. However, their internal volume (100 ml) and possible carbon dioxide reflection raised concerns. Therefore, we compared carbon dioxide elimination of both with a heat moisture exchanger (HME, 35 ml) in a test lung model. A constant flow of carbon dioxide was insufflated into the test lung, ventilated with 500 ml, 10 breaths per minute. HME, MIRUS and AnaConDa were connected successively...
January 27, 2018: Journal of Clinical Monitoring and Computing
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