Expiratory threshold load under extracorporeal circulation: effects of vagal afferents

1983 ◽  
Vol 55 (2) ◽  
pp. 307-315 ◽  
Author(s):  
Y. Jammes ◽  
P. T. Bye ◽  
R. L. Pardy ◽  
C. Katsardis ◽  
S. Esau ◽  
...  
Keyword(s):  
Mechanical Vibration ◽  
Muscle Spindles ◽  
Vagal Afferents ◽  
Abdominal Muscles ◽  
Vagus Nerves ◽  
Linea Alba ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Anesthetized Dogs ◽  
Proprioceptive Afferents

Nine anesthetized dogs breathed against an expiratory threshold load (ETL) applied by switching the expiratory circuit into a column of H2O to a depth of 20-30 cm. Arterial blood gas tensions were maintained in the normal range by placing the dogs under arteriovenous bypass to avoid any uncontrolled chemostimulation. There was an increase in integrated electromyogram activity of the diaphragm with the ETL. This was rarely observed after cold block of the vagus nerves which also reduced the evoked expiratory activity. The ventilatory response to hypercapnia was greatly depressed under loaded breathing whether vagal afferents were intact or blocked by cold. Both inspiratory drive and ventilatory timing were affected, suggesting that the central integration of chemosensitive afferents was altered. Proof of supraspinal projections of proprioceptive inputs from abdominal muscles was provided by the demonstration of changes in ventilatory timing during selective activation of muscle spindles in abdominal muscles by high-frequency mechanical vibration applied to the linea alba. Thus these observations suggest that during ETL breathing, a possible interaction exists between chemoreflex drive and proprioceptive afferents.

Vagal afferents essential for abdominal muscle activity during lung inflation in cats

1976 ◽  
Vol 41 (3) ◽  
pp. 310-315 ◽  
Author(s):  
J. A. Russell ◽  
B. Bishop
Keyword(s):  
Muscle Activity ◽  
Abdominal Muscle ◽  
Vagal Afferents ◽  
Abdominal Muscles ◽  
Vagus Nerves ◽  
Lung Inflation ◽  
Muscle Response ◽  
Great Vessels ◽  
Different Levels

Maintained inflation of the lung evokes abdominal muscle activity in anesthetized cats only if the vagus nerves are intact, indicating the importance of vagal receptors. The location of these receptors was determined in 14 anesthetized cats by comparing prevagotomy inflation responses of the abdominal muscles and diaphragm to the responses obtained after section of the thoracic vagi at one of three different levels. The abdominal muscle and diaphragm responses to maintained lung inflation persisted following vagotomy below the roots of the lung or denervation of the heart and great vessels. Denervation at the root of the lung, however, abolished the abdominal muscle response and the Hering-Breuer inflation reflex of the diaphragm. It is concluded that pulmonary receptors are essential for the abdominal expiratory activity, but vagal receptors in the abdomen, esophagus, trachea, heart and great vessels are not.

Vagal feedback with expiratory threshold load under extracorporeal circulation

1983 ◽  
Vol 55 (2) ◽  
pp. 316-322 ◽  
Author(s):  
Y. Jammes ◽  
P. T. Bye ◽  
R. L. Pardy ◽  
C. Roussos
Keyword(s):  
Extracorporeal Circulation ◽  
Vagal Stimulation ◽  
Inhibitory Response ◽  
Vagal Afferents ◽  
Vagus Nerves ◽  
Anesthetized Dogs ◽  
Expiratory Muscles ◽  
Evoked Activity ◽  
Proprioceptive Inputs ◽  
Stimulation Of

In 11 anesthetized dogs placed under extracorporeal circulation, the vagal feedback was tested by electrical stimulation of the vagus nerves with cold block of their caudal part and by passive lung hyperinflation. The apneic response to such vagal stimulation progressively disappeared during expiratory threshold load breathing but then returned to control values some minutes after the load was removed. This suppression of the inhibitory response to stimulation of the vagus nerves was usually observed when vagal afferents were intact or blocked by cold. However, it was not observed whether no evoked activity continued in expiratory muscles after the cold block, or after suppression of all proprioceptive muscular afferents after transection of the spinal cord at C6 level. These results strongly suggest that enhancement of proprioceptive inputs to the respiratory centers counteracts the vagally mediated inspiratory “off-switch” mechanisms.

Role of hilar nerve afferents in hyperpnea of exercise

1985 ◽  
Vol 59 (3) ◽  
pp. 798-806 ◽  
Author(s):  
C. Flynn ◽  
H. V. Forster ◽  
L. G. Pan ◽  
G. E. Bisgard
Keyword(s):  
Minute Ventilation ◽  
Blood Gases ◽  
Vagal Afferents ◽  
Vagus Nerves ◽  
Inspiratory Time ◽  
Arterial Pco2 ◽  
Arterial Blood ◽  
Arterial Ph ◽  
Cervical Vagotomy

The objective of this study was to determine the role of hilar nerve (lung vagal) afferents in the hyperpnea of exercise. Ten ponies were studied before and 2–4 wk and 3–12 mo after sectioning only the hilar branches of the vagus nerves (HND). After HND, lung volume feedback to the medullary centers was attenuated as indicated in the anesthetized state by 1) attenuation or absence of the Hering-Breuer inflation reflex (P less than 0.01) and 2) attenuation of the lengthened inspiratory time (TI) when the airway was occluded at end expiration (P less than 0.01). Moreover, after HND in the awake state, there was an increase in the ratio of TI to total cycle time (P less than 0.01). These changes verify a compromise in lung innervation comparable to cervical vagotomy. Resting arterial PCO2, PO2, and pH were not altered following HND (P greater than 0.10). Moreover, at three levels of mild and moderate treadmill exercise, no difference in either the temporal pattern or the absolute levels of arterial blood gases and arterial pH was found between pre- and post-HND studies (P greater than 0.10). In addition, minute ventilation (VE) at rest and during exercise was not altered by HND (P greater than 0.10). However, 2–4 wk after HND the increase in breathing frequency (f) during exercise was less, whereas the increase in tidal volume during exercise was greater than pre-HND (P less than 0.05). The reduced f was due to an increase in TI with no change in expiratory time. We conclude that lung afferents via the hilar nerves influence the pattern of breathing at rest and during exercise in ponies.

Atrial fibrillation associated with carbon monoxide poisoning

2019 ◽  
pp. 203-206
Author(s):  
Mevlut Demir ◽  
◽  
Muslum Sahin ◽  
Ahmet Korkmaz ◽  
◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Carbon Monoxide ◽  
Sinus Rhythm ◽  
Partial Pressure ◽  
Motor Vehicle ◽  
Carbon Monoxide Poisoning ◽  
Venous Blood ◽  
Blood Gas ◽  
Arterial Blood Gas ◽  
Arterial Blood

Carbon monoxide intoxication occurs usually via inhalation of carbon monoxide that is emitted as a result of a fire, furnace, space heater, generator, motor vehicle. A 37-year-old male patient was admitted to the emergency department at about 5:00 a.m., with complaints of nausea, vomiting and headache. He was accompanied by his wife and children. His venous blood gas measures were: pH was 7.29, partial pressure of carbon dioxide (pCO2) was 42 mmHg, partial pressure of oxygen (pO2) was 28 mmHg, carboxyhemoglobin (COHb) was 12.7% (reference interval: 0.5%-2.5%) and oxygen saturation was 52.4%. Electrocardiogram (ECG) examination showed that the patient was not in sinus rhythm but had atrial fibrillation. After three hours the laboratory examination was repeated: Troponin was 1.2 pg/ml and in the arterial blood gas COHb was 3%. The examination of the findings on the monitor showed that the sinus rhythm was re-established. The repeated ECG examination confirmed the conversion to the sinus rhythm. He was monitored with the normobaric oxygen administration.

Popliteal artery cannulation as a saviour during prone positioning

2020 ◽  
Vol 13 (6) ◽  
pp. e234370
Author(s):  
Narayan Bala ◽  
Vinay Pathak ◽  
Shilpa Goyal ◽  
Nikhil Kothari
Keyword(s):  
Prone Position ◽  
Popliteal Artery ◽  
Blood Pressure Monitoring ◽  
Arterial Cannulation ◽  
Invasive Blood Pressure ◽  
Arterial Blood Gas ◽  
Artery Cannulation ◽  
Arterial Blood ◽  
Arterial Cannula ◽  
Invasive Blood Pressure Monitoring

The cannulation of the peripheral artery is a prerequisite for invasive blood pressure monitoring and repeated arterial blood gas sampling. Radial artery is commonly used site for inserting an arterial cannula. Many times, either during the change of posture or during prone ventilation, the arterial cannula gets displaced, and it is challenging to reinsert the arterial cannula in the lateral or prone position. In such circumstances, an alternative site of arterial cannulation needs to be looked into; we report a case in which the popliteal artery was used for arterial cannulation while the patient was in a prone position.

scholarly journals Evaluation of percutaneous transcatheter embolization for pulmonary arteriovenous malformations

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
ZhengZhong Wu ◽  
JunQing Lin ◽  
WeiZhu Yang ◽  
Na Jiang ◽  
Ning Huang ◽  
...  
Keyword(s):  
New York ◽  
Success Rate ◽  
Arteriovenous Malformations ◽  
Heart Association ◽  
Transcatheter Embolization ◽  
Pulmonary Arteriovenous Malformations ◽  
Technical Success ◽  
Arterial Blood Gas ◽  
Technical Success Rate ◽  
Arterial Blood

Abstract Background The purpose of this study was to assess the safety and efficacy of percutaneous transcatheter embolization (TCE) for the treatment of pulmonary arteriovenous malformations (PAVMs). Methods Forty-three consecutive patients (n = 17 males; n = 26 females) with 72 untreated PAVMs underwent coil and/or plug embolization between January 2010 and February 2018. The mean patient age was 42 ± 14 years (range 19–71 years). The median size of the feeding artery was 7.9 ± 2.9 mm (range 3.5–14.0 mm). The arterial blood gas level and cardiac function of all patients were analysed. The technical success rate, recanalization rate, and complications were evaluated. Computed tomography angiography (CTA) examinations were scheduled for 12 months after treatment and every 2–4 years thereafter. Results Twenty-five PAVMs were treated with coils alone, twenty-one were treated with plugs alone, and twenty-six were treated with both coils and plugs. The technical success rate was 100%. There were no complications during operation. However, one patient (2.3%) had pulmonary thrombosis and embolism post-operation. The patients’ pre-operative and post-operative PaO2 and SaO2 levels were significantly different (p < 0.01). A comparison of the New York Heart Association (NYHA) grade before and after embolization in all patients showed a significant decrease in the post-operative grade (p < 0.01). The 72 PAVMs were divided into three groups (coils only group [n = 25], plugs only group [n = 21], and coils/plugs combined group [n = 26]). After 12 months of follow-up, there were seven reperfusion PAVMs in the coil group, seven reperfusion PAVMs in the plug group, and 1 reperfusion PAVM in the combined group. There were significant differences between the two groups and the combined group. Conclusion Percutaneous TCE is safe and effective for the treatment of PAVMs. A combination of coils and vascular plugs may be useful for preventing recanalization after the embolization of PAVMs.

scholarly journals d-Cystine di(m)ethyl ester reverses the deleterious effects of morphine on ventilation and arterial blood gas chemistry while promoting antinociception

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benjamin Gaston ◽  
Santhosh M. Baby ◽  
Walter J. May ◽  
Alex P. Young ◽  
Alan Grossfield ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Intracellular Signaling ◽  
Dimethyl Ester ◽  
Diethyl Ester ◽  
Blood Gas ◽  
Negative Effects ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Gas Chemistry ◽  
Ventilatory Drive

AbstractWe have identified thiolesters that reverse the negative effects of opioids on breathing without compromising antinociception. Here we report the effects of d-cystine diethyl ester (d-cystine diEE) or d-cystine dimethyl ester (d-cystine diME) on morphine-induced changes in ventilation, arterial-blood gas chemistry, A-a gradient (index of gas-exchange in the lungs) and antinociception in freely moving rats. Injection of morphine (10 mg/kg, IV) elicited negative effects on breathing (e.g., depression of tidal volume, minute ventilation, peak inspiratory flow, and inspiratory drive). Subsequent injection of d-cystine diEE (500 μmol/kg, IV) elicited an immediate and sustained reversal of these effects of morphine. Injection of morphine (10 mg/kg, IV) also elicited pronounced decreases in arterial blood pH, pO2 and sO2 accompanied by pronounced increases in pCO2 (all indicative of a decrease in ventilatory drive) and A-a gradient (mismatch in ventilation-perfusion in the lungs). These effects of morphine were reversed in an immediate and sustained fashion by d-cystine diME (500 μmol/kg, IV). Finally, the duration of morphine (5 and 10 mg/kg, IV) antinociception was augmented by d-cystine diEE. d-cystine diEE and d-cystine diME may be clinically useful agents that can effectively reverse the negative effects of morphine on breathing and gas-exchange in the lungs while promoting antinociception. Our study suggests that the d-cystine thiolesters are able to differentially modulate the intracellular signaling cascades that mediate morphine-induced ventilatory depression as opposed to those that mediate morphine-induced antinociception and sedation.

scholarly journals Prehospital Diagnosis of Shortness of Breath Caused by Profound Metformin-Associated Metabolic Acidosis

Healthcare ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 74
Author(s):  
Pietro Elias Fubini ◽  
Laurent Suppan
Keyword(s):  
Metabolic Acidosis ◽  
Hospital Setting ◽  
Blood Gases ◽  
Shortness Of Breath ◽  
Potential Harm ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Common Causes ◽  
Prehospital Diagnosis ◽  
Gas Measurement

Shortness of breath is a common complaint among patients in emergency medicine. While most common causes are usually promptly identified, less frequent aetiologies might be challenging to diagnose, especially in the pre-hospital setting. We report a case of prehospital dyspnoea initially ascribed to pulmonary oedema which turned out to be the result of profound metformin-associated metabolic acidosis. This diagnosis was already made during the prehospital phase by virtue of arterial blood gas measurement. Pre-hospital measurement of arterial blood gases is therefore feasible and can improve diagnostic accuracy in the field, thus avoiding unnecessary delay and potential harm to the patient before initiating the appropriate therapeutic actions.

scholarly journals Accuracy of two pulse-oximetry measurements for INTELLiVENT-ASV in mechanically ventilated patients: a prospective observational study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shinshu Katayama ◽  
Jun Shima ◽  
Ken Tonai ◽  
Kansuke Koyama ◽  
Shin Nunomiya
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Prospective Observational Study ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Arterial Blood Gas ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Arterial Blood ◽  
Ventilated Patients

AbstractRecently, maintaining a certain oxygen saturation measured by pulse oximetry (SpO2) range in mechanically ventilated patients was recommended; attaching the INTELLiVENT-ASV to ventilators might be beneficial. We evaluated the SpO2 measurement accuracy of a Nihon Kohden and a Masimo monitor compared to actual arterial oxygen saturation (SaO2). SpO2 was simultaneously measured by a Nihon Kohden and Masimo monitor in patients consecutively admitted to a general intensive care unit and mechanically ventilated. Bland–Altman plots were used to compare measured SpO2 with actual SaO2. One hundred mechanically ventilated patients and 1497 arterial blood gas results were reviewed. Mean SaO2 values, Nihon Kohden SpO2 measurements, and Masimo SpO2 measurements were 95.7%, 96.4%, and 96.9%, respectively. The Nihon Kohden SpO2 measurements were less biased than Masimo measurements; their precision was not significantly different. Nihon Kohden and Masimo SpO2 measurements were not significantly different in the “SaO2 < 94%” group (P = 0.083). In the “94% ≤ SaO2 < 98%” and “SaO2 ≥ 98%” groups, there were significant differences between the Nihon Kohden and Masimo SpO2 measurements (P < 0.0001; P = 0.006; respectively). Therefore, when using automatically controlling oxygenation with INTELLiVENT-ASV in mechanically ventilated patients, the Nihon Kohden SpO2 sensor is preferable.Trial registration UMIN000027671. Registered 7 June 2017.

scholarly journals Can Alveolar-Arterial Difference and Lung Ultrasound Help the Clinical Decision Making in Patients with COVID-19?

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 761
Author(s):  
Gianmarco Secco ◽  
Francesco Salinaro ◽  
Carlo Bellazzi ◽  
Marco La Salvia ◽  
Marzia Delorenzo ◽  
...  
Keyword(s):  
Decision Making ◽  
Clinical Decision Making ◽  
Lung Ultrasound ◽  
Signs And Symptoms ◽  
Clinical Decision ◽  
Arterial Oxygen ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Lung Dysfunction ◽  
Close Relationship

Background: COVID-19 is an emerging infectious disease, that is heavily challenging health systems worldwide. Admission Arterial Blood Gas (ABG) and Lung Ultrasound (LUS) can be of great help in clinical decision making, especially during the current pandemic and the consequent overcrowding of the Emergency Department (ED). The aim of the study was to demonstrate the capability of alveolar-to-arterial oxygen difference (AaDO2) in predicting the need for subsequent oxygen support and survival in patients with COVID-19 infection, especially in the presence of baseline normal PaO2/FiO2 ratio (P/F) values. Methods: A cohort of 223 swab-confirmed COVID-19 patients underwent clinical evaluation, blood tests, ABG and LUS in the ED. LUS score was derived from 12 ultrasound lung windows. AaDO2 was derived as AaDO2 = ((FiO2) (Atmospheric pressure − H2O pressure) − (PaCO2/R)) − PaO2. Endpoints were subsequent oxygen support need and survival. Results: A close relationship between AaDO2 and P/F and between AaDO2 and LUS score was observed (R2 = 0.88 and R2 = 0.67, respectively; p < 0.001 for both). In the subgroup of patients with P/F between 300 and 400, 94.7% (n = 107) had high AaDO2 values, and 51.4% (n = 55) received oxygen support, with 2 ICU admissions and 10 deaths. According to ROC analysis, AaDO2 > 39.4 had 83.6% sensitivity and 90.5% specificity (AUC 0.936; p < 0.001) in predicting subsequent oxygen support, whereas a LUS score > 6 showed 89.7% sensitivity and 75.0% specificity (AUC 0.896; p < 0.001). Kaplan–Meier curves showed different mortality in the AaDO2 subgroups (p = 0.0025). Conclusions: LUS and AaDO2 are easy and effective tools, which allow bedside risk stratification in patients with COVID-19, especially when P/F values, signs, and symptoms are not indicative of severe lung dysfunction.

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