scholarly journals A Two-handed Jaw-thrust Technique Is Superior to the One-handed “EC-clamp” Technique for Mask Ventilation in the Apneic Unconscious Person

2010 ◽  
Vol 113 (4) ◽  
pp. 873-879 ◽  
Author(s):  
Aaron M. Joffe ◽  
Scott Hetzel ◽  
Elaine C. Liew
Keyword(s):  
Body Weight ◽  
Tidal Volume ◽  
Dead Space ◽  
Minute Ventilation ◽  
Mask Ventilation ◽  
Predicted Body Weight ◽  
Airway Patency ◽  
Clamp Technique ◽  
The One ◽  
Dead Space Ventilation

Background Mask ventilation is considered a "basic" skill for airway management. A one-handed "EC-clamp" technique is most often used after induction of anesthesia with a two-handed jaw-thrust technique reserved for difficult cases. Our aim was to directly compare both techniques with the primary outcome of air exchange in the lungs. Methods Forty-two elective surgical patients were mask-ventilated after induction of anesthesia by using a one-handed "EC-clamp" technique and a two-handed jaw-thrust technique during pressure-control ventilation in randomized, crossover fashion. When unresponsive to a jaw thrust, expired tidal volumes were recorded from the expiratory limb of the anesthesia machine each for five consecutive breaths. Inadequate mask ventilation and dead-space ventilation were defined as an average tidal volume less than 4 ml/kg predicted body weight or less than 150 ml/breath, respectively. Differences in minute ventilation and tidal volume between techniques were assessed with the use of a mixed-effects model. Results Patients were (mean ± SD) 56 ± 18 yr old with a body mass index of 30 ± 7.1 kg/m. Minute ventilation was 6.32 ± 3.24 l/min with one hand and 7.95 ± 2.70 l/min with two hands. The tidal volume was 6.80 ± 3.10 ml/kg predicted body weight with one hand and 8.60 ± 2.31 ml/kg predicted body weight with two hands. Improvement with two hands was independent of the order used. Inadequate or dead-space ventilation occurred more frequently during use of the one-handed compared with the two-handed technique (14 vs. 5%; P = 0.013). Conclusion A two-handed jaw-thrust mask technique improves upper airway patency as measured by greater tidal volumes during pressure-controlled ventilation than a one-handed "EC-clamp" technique in the unconscious apneic person.

scholarly journals Assessment of Fluid Responsiveness After Tidal Volume Challenge During Pressure-Controlled Ventilation Volume Guaranteed: An observational study

2020 ◽  
Author(s):  
Yu Jiang ◽  
Lingling Jiang ◽  
Jun Hu ◽  
Ye Zhang
Keyword(s):  
Body Weight ◽  
Tidal Volume ◽  
Fluid Responsiveness ◽  
Transient Increase ◽  
Anesthesia Induction ◽  
Predicted Body Weight ◽  
Controlled Ventilation ◽  
Pressure Controlled Ventilation ◽  
Pressure Controlled ◽  
Volume Challenge

Abstract Background: The reliability of pulse pressure variation (PPV) and stroke volume variation (SVV) to predict fluid responsiveness have not previously been established when using pressure-controlled ventilation-volume guaranteed (PCV-VG) mode. We hypothesized that with a transient increase in tidal volume from 6 to 8 mL/kg of predicted body weight (PBW), which we reference as the “tidal volume challenge (TVC)”, the changes to PPV and SVV will be an indicator of fluid responsiveness.Methods: The patients were first ventilated with a tidal volume of (Vt) 6 mL/kg of predicted body weight (PBW) using PCV-VG. Following intravenous anesthesia induction, PPV6 and SVV6 were recorded, then the TVC was performed, which increased Vt from 6 mL/kg to 8 mL/kg PBW for 1 minute and PPV8 and SVV8 were recorded again. The changes in value of PPV and SVV (ΔPPV6-8 and ΔSVV6-8) were calculated after TVC. Following the minute of TVC, the tidal volume was returned to 6 ml/kg PBW for the fluid challenge (FC), a colloid infusion of 6ml/kg PBW for 20 minutes. Patients were classified as responders if there was an increase in cardiac index (CI) of more than 15% after FC, otherwise the patients were identified as non-responders. Eligible patients were divided into groups of responders or non-responders.Results: 37 patients were classified as responders and 44 were non-responders. PPV6 and SVV6 could not predict the fluid responsiveness, while PPV8 and SVV8 could predict the fluid responsiveness when using PCV-VG mode. The changes in value of PPV and SVV after TVC (ΔPPV6-8 and ΔSVV6-8) identified true fluid responders with the highest sensitivity and specificity in the above variables, which predicted fluid responsiveness with the area under the receiver operating characteristic curves (AUCs) (95% CIs) being 0.96 (0.93-1.00) and 0.98 (0.96-1.00), respectively. No significant difference was found when comparing the AUCs of ΔPPV6-8 and ΔSVV6-8 (P > 0.05). Linear correlation was represented between the change value of CI after FC and the change value of SVV or PPV after TVC (r = 0.68; P < 0.0001 and r = 0.77; P < 0.0001, respectively).Conclusions: A transient increase in tidal volume, which we reference as the “tidal volume challenge (TVC)” could enhance the predictive value of PPV and SVV for the evaluation of fluid responsiveness in patients under ventilation with PCV-VG.Trial registration: Chinese Clinical Trial Registry (ChiCTR2000028995). Prospectively registered on 11 January 2020. http://www.medresman.org.

scholarly journals Reductions in dead space ventilation with nasal high flow depend on physiological dead space volume: metabolic hood measurements during sleep in patients with COPD and controls

2018 ◽  
Vol 51 (5) ◽  
pp. 1702251 ◽  
Author(s):  
Paolo Biselli ◽  
Kathrin Fricke ◽  
Ludger Grote ◽  
Andrew T. Braun ◽  
Jason Kirkness ◽  
...  
Keyword(s):  
Respiratory Rate ◽  
Dead Space ◽  
Minute Ventilation ◽  
High Flow ◽  
Physiological Dead Space ◽  
Copd Patients ◽  
Dead Space Volume ◽  
Anatomical Dead Space ◽  
Dead Space Ventilation ◽  
Space Volume

Nasal high flow (NHF) reduces minute ventilation and ventilatory loads during sleep but the mechanisms are not clear. We hypothesised NHF reduces ventilation in proportion to physiological but not anatomical dead space.11 subjects (five controls and six chronic obstructive pulmonary disease (COPD) patients) underwent polysomnography with transcutaneous carbon dioxide (CO2) monitoring under a metabolic hood. During stable non-rapid eye movement stage 2 sleep, subjects received NHF (20 L·min−1) intermittently for periods of 5–10 min. We measured CO2 production and calculated dead space ventilation.Controls and COPD patients responded similarly to NHF. NHF reduced minute ventilation (from 5.6±0.4 to 4.8±0.4 L·min−1; p<0.05) and tidal volume (from 0.34±0.03 to 0.3±0.03 L; p<0.05) without a change in energy expenditure, transcutaneous CO2 or alveolar ventilation. There was a significant decrease in dead space ventilation (from 2.5±0.4 to 1.6±0.4 L·min−1; p<0.05), but not in respiratory rate. The reduction in dead space ventilation correlated with baseline physiological dead space fraction (r2=0.36; p<0.05), but not with respiratory rate or anatomical dead space volume.During sleep, NHF decreases minute ventilation due to an overall reduction in dead space ventilation in proportion to the extent of baseline physiological dead space fraction.

Effects of Feedback and Education on Nurses’ Clinical Competence in Mechanical Ventilation and Accurate Tidal Volume Setting

2021 ◽  
Author(s):  
Samira Norouzrajabi ◽  
Shahrzad Ghiyasvandian ◽  
Alireza Jeddian ◽  
Ali Karimi Rozveh ◽  
Leila Sayadi
Keyword(s):  
Mechanical Ventilation ◽  
Body Weight ◽  
Tidal Volume ◽  
Clinical Competence ◽  
High Tidal Volume ◽  
Education Intervention ◽  
Predicted Body Weight ◽  
Post Test ◽  
The Mean ◽  
Effects Of Feedback

Background: Patients under mechanical ventilation are at risk of ventilator-associated complications. One of these complications is lung injury due to high tidal volume. Nurses’ competence in mechanical ventilation is critical for preventing ventilator-associated complications. This study assessed the effects of feedback and education on nurses’ clinical competence in mechanical ventilation and accurate tidal volume setting. Methods: This single arm pretest-post-test interventional study was conducted in 2019 at Shariati hospital affiliated to Tehran University of Medical Sciences. Participants were 75 conveniently selected nurses. Initially, nurses’ clinical competence in mechanical ventilation and ventilator parameters of 250 patients were assessed. A mechanical ventilation -based feedback and education intervention was implemented for nurses. Finally, mechanical ventilation clinical competence of nurses and ventilator parameters of 250 new patients were assessed. Moreover, patients’ height was estimated based on their ulna length and then, their predicted body weight was calculated using their estimated height. Accurate tidal volume was determined per predicted body weight.  Results: The mean score of nurses’ clinical competence increased from 8.27±3.09 at pretest to 10.07±3.34 at post-test (p<0.001). The mean values of both total tidal volume and tidal volume per kilogram of predicted body weight were significantly reduced respectively from 529.84±69.11 and 9.11±1.73 (ml) at pretest to 476.30±31.01 and 7.79±1.14 (ml) at post-test (p<0.001). Conclusion: The feedback and education intervention is effective in promoting nurses’ clinical competence in mechanical ventilation and reducing tidal volume. Thereby, it can reduce lung injuries associated with high tidal volume and ensure patient safety.

Effects of Combined Abdominal and Thoracic Airsac Occlusion on Respiration in Domestic Fowl

1990 ◽  
Vol 152 (1) ◽  
pp. 93-100 ◽  
Author(s):  
JOHN BRACKENBURY ◽  
JANE AMAKU
Keyword(s):  
Metabolic Rate ◽  
Tidal Volume ◽  
Dead Space ◽  
Domestic Fowl ◽  
Detrimental Effect ◽  
Minute Ventilation ◽  
Respiratory Pattern ◽  
Blood Gas ◽  
Control Value ◽  
Air Sacs

Ventilation and respiratory and blood gas tensions were monitored at rest and during running exercise, following bilateral occlusion of the cranial and caudal thoracic and the abdominal air sacs. This represents a removal of approximately 70% of the total air-sac capacity. At rest, the birds were strongly hypoxaemic/hypercapnaemic. Ventilation was maintained at its control value but respiratory frequency was significantly increased and tidal volume diminished. The birds were capable of sustained running at approximately three times the pre-exercise metabolic rate. Minute ventilation during exercise was the same as that of the controls, but breathing was faster and shallower. Exercise had no effect on blood gas tensions in either the control or the experimental birds. There was no evidence of a detrimental effect of air-sac occlusion on the effectiveness of inspiratory airflow valving in the lung: hypoxaemia appeared to be due to the altered respiratory pattern, which resulted in increased dead-space inhalation.

1165: COMPARING TIDAL VOLUME BY PREDICTED BODY WEIGHT IN PEDIATRIC ACUTE RESPIRATORY DISTRESS SYNDROME

2018 ◽  
Vol 46 (1) ◽  
pp. 566-566
Author(s):  
Yi-Jyun Ma, Judith ◽  
Ju-Ming Wong ◽  
Herng Lee Tan ◽  
Tsee Foong Loh ◽  
Jan Hau Lee
Keyword(s):  
Body Weight ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Tidal Volume ◽  
Distress Syndrome ◽  
Predicted Body Weight

Control of breathing and volitional respiratory rhythm in humans

2009 ◽  
Vol 106 (3) ◽  
pp. 904-910 ◽  
Author(s):  
Philippe Haouzi ◽  
Harold J. Bell
Keyword(s):  
Dead Space ◽  
Minute Ventilation ◽  
Premotor Cortex ◽  
Respiratory Rhythm ◽  
Background Level ◽  
Rhythmic Activity ◽  
Auditory Signal ◽  
Time Interval ◽  
Space Condition ◽  
Dead Space Ventilation

When breathing frequency (f) is imperceptibly increased during a volitionally paced respiratory rhythm imposed by an auditory signal, tidal volume (Vt) decreases such that minute ventilation (V̇e) rises according to f-induced dead-space ventilation changes ( 18 ). As a result, significant change in alveolar ventilation and Pco2 are prevented as f varies. The present study was performed to determine what regulatory properties are retained by the respiratory control system, wherein the spontaneous automatic rhythmic activity is replaced by a volitionally paced rhythm. Six volunteers were asked to trigger each breath cycle on hearing a brief auditory signal. The time interval between subsequent auditory signals was imperceptibly changed for 10–15 min, during 1) air breathing ( condition 1), 2) the addition of a 300 ml of instrumental dead space ( condition 2), 3) an increase in the inspired level of CO2 ( condition 3), and 4) light exercise ( condition 4). We found that as f was slowly increased the elaborated Vt decreased in accordance to the background level of CO2 and metabolic rate. Indeed, for any given breath duration, Vt was shifted upward in condition 2 vs. 1, whereas the slope of Vt changes according to the volitionally rhythm was much steeper in conditions 3 and 4 vs. 1. The resulting changes in V̇e offset any f-induced changes in dead-space ventilation in all conditions. We conclude that there is an inherent, fundamental mechanism that elaborates Vt based on f when imposed by the premotor cortex in humans. The chemoreflex and exercise drive to breath interacts with this cortically mediated rhythm maintaining alveolar rather than V̇e constant as f changes. The implications of our findings are discussed in the context of our current understanding of the central generation of breathing rhythm.

Physiological dead space during high-frequency ventilation in dogs

1984 ◽  
Vol 57 (3) ◽  
pp. 881-887 ◽  
Author(s):  
G. G. Weinmann ◽  
W. Mitzner ◽  
S. Permutt
Keyword(s):  
Gas Exchange ◽  
Tidal Volume ◽  
Dead Space ◽  
High Frequency ◽  
Minute Ventilation ◽  
Alveolar Ventilation ◽  
High Frequency Ventilation ◽  
Physiological Dead Space ◽  
Frequency Ventilation ◽  
Normal Ventilation

Tidal volumes used in high-frequency ventilation (HFV) may be smaller than anatomic dead space, but since gas exchange does take place, physiological dead space (VD) must be smaller than tidal volume (VT). We quantified changes in VD in three dogs at constant alveolar ventilation using the Bohr equation as VT was varied from 3 to 15 ml/kg and frequency (f) from 0.2 to 8 Hz, ranges that include normal as well as HFV. We found that VD was relatively constant at tidal volumes associated with normal ventilation (7–15 ml/kg) but fell sharply as VT was reduced further to tidal volumes associated with HFV (less than 7 ml/kg). The frequency required to maintain constant alveolar ventilation increased slowly as tidal volume was decreased from 15 to 7 ml/kg but rose sharply with attendant rapid increases in minute ventilation as tidal volumes were decreased to less than 7 ml/kg. At tidal volumes less than 7 ml/kg, the data deviated substantially from the conventional alveolar ventilation equation [f(VT - VD) = constant] but fit well a model derived previously for HFV. This model predicts that gas exchange with volumes smaller than dead space should vary approximately as the product of f and VT2.

scholarly journals Nasal high flow reduces minute ventilation during sleep through a decrease of carbon dioxide rebreathing

2019 ◽  
Vol 126 (4) ◽  
pp. 863-869 ◽  
Author(s):  
Maximilian Pinkham ◽  
Russel Burgess ◽  
Toby Mündel ◽  
Stanislav Tatkov
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Tidal Volume ◽  
Respiratory Rate ◽  
Dead Space ◽  
Minute Ventilation ◽  
Control Ventilation ◽  
High Flow ◽  
Carbon Dioxide Rebreathing ◽  
Anatomical Dead Space

Nasal high flow (NHF) is an emerging therapy for respiratory support, but knowledge of the mechanisms and applications is limited. It was previously observed that NHF reduces the tidal volume but does not affect the respiratory rate during sleep. The authors hypothesized that the decrease in tidal volume during NHF is due to a reduction in carbon dioxide (CO2) rebreathing from dead space. In nine healthy males, ventilation was measured during sleep using calibrated respiratory inductance plethysmography (RIP). Carbogen gas mixture was entrained into 30 l/min of NHF to obtain three levels of inspired CO2: 0.04% (room air), 1%, and 3%. NHF with room air reduced tidal volume by 81 ml, SD 25 ( P < 0.0001) from a baseline of 415 ml, SD 114, but did not change respiratory rate; tissue CO2 and O2 remained stable, indicating that gas exchange had been maintained. CO2 entrainment increased tidal volume close to baseline with 1% CO2 and greater than baseline with 3% CO2 by 155 ml, SD 79 ( P = 0.0004), without affecting the respiratory rate. It was calculated that 30 l/min of NHF reduced the rebreathing of CO2 from anatomical dead space by 45%, which is equivalent to the 20% reduction in tidal volume that was observed. The study proves that the reduction in tidal volume in response to NHF during sleep is due to the reduced rebreathing of CO2. Entrainment of CO2 into the NHF can be used to control ventilation during sleep. NEW & NOTEWORTHY The findings in healthy volunteers during sleep show that nasal high flow (NHF) with a rate of 30 l/min reduces the rebreathing of CO2 from anatomical dead space by 45%, resulting in a reduced minute ventilation, while gas exchange is maintained. Entrainment of CO2 into the NHF can be used to control ventilation during sleep.

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