1041: INFLUENCE OF TIDAL VOLUME ON SEDATIVE DOSE REQUIREMENTS IN MECHANICALLY VENTILATED ADULTS

2018 ◽  
Vol 46 (1) ◽  
pp. 504-504
Author(s):  
Ben Jagow ◽  
Elizabeth Short ◽  
Jacky Kruser ◽  
Bryan Lizza
Keyword(s):  
Tidal Volume ◽  
Mechanically Ventilated ◽  
Sedative Dose

scholarly journals Management of hypercapnia in critically ill mechanically ventilated patients—A narrative review of literature

2020 ◽  
Vol 21 (4) ◽  
pp. 327-333
Author(s):  
Ravindranath Tiruvoipati ◽  
Sachin Gupta ◽  
David Pilcher ◽  
Michael Bailey
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Dead Space ◽  
Hypercapnic Acidosis ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Low Tidal Volume ◽  
Volume Ventilation ◽  
Low Volume ◽  
Ventilated Patients

The use of lower tidal volume ventilation was shown to improve survival in mechanically ventilated patients with acute lung injury. In some patients this strategy may cause hypercapnic acidosis. A significant body of recent clinical data suggest that hypercapnic acidosis is associated with adverse clinical outcomes including increased hospital mortality. We aimed to review the available treatment options that may be used to manage acute hypercapnic acidosis that may be seen with low tidal volume ventilation. The databases of MEDLINE and EMBASE were searched. Studies including animals or tissues were excluded. We also searched bibliographic references of relevant studies, irrespective of study design with the intention of finding relevant studies to be included in this review. The possible options to treat hypercapnia included optimising the use of low tidal volume mechanical ventilation to enhance carbon dioxide elimination. These include techniques to reduce dead space ventilation, and physiological dead space, use of buffers, airway pressure release ventilation and prone positon ventilation. In patients where hypercapnic acidosis could not be managed with lung protective mechanical ventilation, extracorporeal techniques may be used. Newer, minimally invasive low volume venovenous extracorporeal devices are currently being investigated for managing hypercapnia associated with low and ultra-low volume mechanical ventilation.

Respiratory impedances and acinar gas transfer in a canine model for emphysema

1997 ◽  
Vol 83 (1) ◽  
pp. 179-188 ◽  
Author(s):  
George M. Barnas ◽  
Paul A. Delaney ◽  
Ileana Gheorghiu ◽  
Srinivas Mandava ◽  
Robert G. Russell ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Chest Wall ◽  
Canine Model ◽  
Gas Transfer ◽  
Secondary Complications ◽  
Flow Measurements ◽  
Mechanically Ventilated ◽  
Tissue Sections ◽  
Acinar Structure ◽  
Blood Flow Measurements

Barnas, George M., Paul A. Delaney, Ileana Gheorghiu, Srinivas Mandava, Robert G. Russell, Renée Kahn, and Colin F. Mackenzie. Respiratory impedances and acinar gas transfer in a canine model for emphysema. J. Appl. Physiol. 83(1): 179–188, 1997.—We examined how the changes in the acini caused by emphysema affected gas transfer out of the acinus (Taci) and lung and chest wall mechanical properties. Measurements were taken from five dogs before and 3 mo after induction of severe bilateral emphysema by exposure to papain aerosol (170–350 mg/dose) for 4 consecutive wk. With the dogs anesthetized, paralyzed, and mechanically ventilated at 0.2 Hz and 20 ml/kg, we measured Taciby the rate of washout of133Xe from an area of the lung with occluded blood flow. Measurements were repeated at positive end-expiratory pressures (PEEP) of 10, 5, 15, 0, and 20 cmH2O. We also measured dynamic elastances and resistances of the lungs (El and Rl, respectively) and chest wall at the different PEEP and during sinusoidal forcing in the normal range of breathing frequency and tidal volume. After final measurements, tissue sections from five randomly selected areas of the lung each showed indications of emphysema. Taciduring emphysema was similar to that in control dogs. Eldecreased by ∼50% during emphysema ( P < 0.05) but did not change its dependence on frequency or tidal volume. Rl did not change ( P > 0.05) at the lowest frequency studied (0.2 Hz), but in some dogs it increased compared with control at the higher frequencies. Chest wall properties were not changed by emphysema ( P > 0.05). We suggest that although large changes in acinar structure and El occur during uncomplicated bilateral emphysema, secondary complications must be present to cause several of the characteristic dysfunctions seen in patients with emphysema.

Pulmonary mechanics during rapid mechanical ventilation in rabbits with saline-lavaged lungs

1986 ◽  
Vol 61 (4) ◽  
pp. 1431-1437 ◽  
Author(s):  
J. J. Perez Fontan ◽  
B. S. Turner ◽  
G. P. Heldt ◽  
G. A. Gregory
Keyword(s):  
Tidal Volume ◽  
Gas Flow ◽  
Transpulmonary Pressure ◽  
Inspiratory Flow ◽  
Pulmonary Mechanics ◽  
Mechanically Ventilated ◽  
Ventilatory Rate ◽  
Residual Capacity ◽  
Pressure Volume Relationship ◽  
Linear Ramp

Infants with respiratory failure are frequently mechanically ventilated at rates exceeding 60 breaths/min. We analyzed the effect of ventilatory rates of 30, 60, and 90 breaths/min (inspiratory times of 0.6, 0.3, and 0.2 s, respectively) on the pressure-flow relationships of the lungs of anesthetized paralyzed rabbits after saline lavage. Tidal volume and functional residual capacity were maintained constant. We computed effective inspiratory and expiratory resistance and compliance of the lungs by dividing changes in transpulmonary pressure into resistive and elastic components with a multiple linear regression. We found that mean pulmonary resistance was lower at higher ventilatory rates, while pulmonary compliance was independent of ventilatory rate. The transpulmonary pressure developed by the ventilator during inspiration approximated a linear ramp. Gas flow became constant and the pressure-volume relationship linear during the last portion of inspiration. Even at a ventilatory rate of 90 breaths/min, 28–56% of the tidal volume was delivered with a constant inspiratory flow. Our findings are consistent with the model of Bates et al. (J. Appl. Physiol. 58: 1840–1848, 1985), wherein the distribution of gas flow within the lungs depends predominantly on resistive factors while inspiratory flow is increasing, and on elastic factors while inspiratory flow is constant. This dynamic behavior of the surfactant-depleted lungs suggests that, even with very short inspiratory times, distribution of gas flow within the lungs is in large part determined by elastic factors. Unless the inspiratory time is further shortened, gas flow may be directed to areas of increased resistance, resulting in hyperinflation and barotrauma.

Tachykinins mediate bronchoconstriction elicited by isocapnic hyperpnea in guinea pigs

1989 ◽  
Vol 66 (3) ◽  
pp. 1108-1112 ◽  
Author(s):  
D. W. Ray ◽  
C. Hernandez ◽  
A. R. Leff ◽  
J. M. Drazen ◽  
J. Solway
Keyword(s):  
Tidal Volume ◽  
Guinea Pigs ◽  
Minute Ventilation ◽  
Response Curves ◽  
Mechanically Ventilated ◽  
Stimulus Response ◽  
Respiratory System Resistance ◽  
Water Saturated ◽  
And Control ◽  
Isocapnic Hyperpnea

We tested the hypothesis that tachykinins mediate hyperpnea-induced bronchoconstriction (HIB) in 28 guinea pigs. Stimulus-response curves to increasing minute ventilation with dry gas were generated in animals depleted of tachykinins by capsaicin pretreatment and in animals pretreated with phosphoramidon, a neutral metalloendopeptidase inhibitor. Sixteen anesthetized guinea pigs received capsaicin (50 mg/kg sc) after aminophylline (10 mg/kg ip) and terbutaline (0.1 mg/kg sc). An additional 12 animals received saline (1 ml sc) instead of capsaicin. One week later, all animals were anesthetized, given propranolol (1 mg/kg iv), and mechanically ventilated (6 ml/kg, 60 breaths/min, 50% O2 in air fully water saturated). Phosphoramidon (0.5 mg iv) was administered to five of the noncapsaicin-treated guinea pigs. Eucapnic dry gas (95% O2–5% CO2) hyperpnea “challenges” were performed by increasing the tidal volume (2–6 ml) and frequency (150 breaths/min) for 5 min. Capsaicin-pretreated animals showed marked attenuation in HIB, with a rightward shift of the stimulus-response curve compared with controls; the estimated tidal volume required to elicit a twofold increase in respiratory system resistance (ES200) was 5.0 ml for capsaicin-pretreated animals vs. 3.7 ml for controls (P less than 0.03). Phosphoramidon-treated animals were more reactive to dry gas hyperpnea compared with control (ES200 = 2.6 ml; P less than 0.0001). Methacholine dose-response curves (10(-11) to 10(-7) mol iv) obtained at the conclusion of the experiments were similar among capsaicin, phosphoramidon, and control groups. These findings implicate tachykinin release as an important mechanism of HIB in guinea pigs.

Relationship between Cr and breathing pattern in mechanically ventilated patients

1994 ◽  
Vol 77 (6) ◽  
pp. 2703-2708 ◽  
Author(s):  
H. Burnet ◽  
M. Bascou-Bussac ◽  
C. Martin ◽  
Y. Jammes
Keyword(s):  
Linear Regression ◽  
Tidal Volume ◽  
Multiple Linear Regression ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Respiratory Frequency ◽  
Upper Airways ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Ventilated Patients

In mechanically ventilated patients the natural gas-conditioning process of the upper airways is bypassed by the use of an endotracheal tube or a tracheostomy. We hypothesized that under these conditions the breathing pattern may greatly influence the convective respiratory heat loss (Cr). Cr values were computed from minute ventilation (VE) and inspiratory and expiratory gas temperatures, which were measured in six patients under mechanical ventilation for the management of cranial trauma. In each patient the effects of 11–20 different breathing patterns were investigated. Relationships between Cr and VE and between combined tidal volume and respiratory frequency were obtained by simple and multiple linear regression methods, respectively. Comparison of the standard errors of estimate indicated that multiple linear regression gives the best fit. Thus, Cr was highly dependent on the breathing pattern and was not related only to VE. For the same VE value, Cr was higher when VE was achieved with high tidal volume and low respiratory frequency. These data are consistent with previous studies in which thermal exchanges through the upper airways were taxed by hyperventilation of frigid air.

scholarly journals An optimized method for estimating the tidal volume from intracardiac or body surface electrocardiographic signals: implications for estimating minute ventilation

2014 ◽  
Vol 307 (3) ◽  
pp. H426-H436 ◽  
Author(s):  
Omid Sayadi ◽  
Eric H. Weiss ◽  
Faisal M. Merchant ◽  
Dheeraj Puppala ◽  
Antonis A. Armoundas
Keyword(s):  
Tidal Volume ◽  
Body Surface ◽  
Minute Ventilation ◽  
Absolute Error ◽  
Accurate Estimation ◽  
Clinical Settings ◽  
Mechanically Ventilated ◽  
Ecg Signals ◽  
Respiratory Signal ◽  
Respiratory Modulation

The ability to accurately monitor tidal volume (TV) from electrocardiographic (ECG) signals holds significant promise for improving diagnosis treatment across a variety of clinical settings. The objective of this study was to develop a novel method for estimating the TV from ECG signals. In 10 mechanically ventilated swine, we collected intracardiac electrograms from catheters in the coronary sinus (CS), left ventricle (LV), and right ventricle (RV), as well as body surface electrograms, while TV was varied between 0 and 750 ml at respiratory rates of 7–14 breaths/min. We devised an algorithm to determine the optimized respirophasic modulation of the amplitude of the ECG-derived respiratory signal. Instantaneous measurement of respiratory modulation showed an absolute error of 72.55, 147.46, 85.68, 116.62, and 50.89 ml for body surface, CS, LV, RV, and RV-CS leads, respectively. Minute TV estimation demonstrated a more accurate estimation with an absolute error of 69.56, 153.39, 79.33, 122.16, and 48.41 ml for body surface, CS, LV, RV, and RV-CS leads, respectively. The RV-CS and body surface leads provided the most accurate estimations that were within 7 and 10% of the true TV, respectively. Finally, the absolute error of the bipolar RV-CS lead was significantly lower than any other lead configuration ( P < 0.0001). In conclusion, we have demonstrated that ECG-derived respiratory modulation provides an accurate estimation of the TV using intracardiac or body surface signals, without the need for additional hardware.

scholarly journals Pneumomediastinum secondary to invasive and non-invasive mechanical ventilation

2019 ◽  
Vol 7 (27) ◽  
pp. 36-42 ◽  
Author(s):  
Sara Mousa ◽  
Hawa Edriss
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Distress Syndrome ◽  
Invasive Mechanical Ventilation ◽  
X Rays ◽  
Mechanically Ventilated ◽  
Non Invasive ◽  
Low Tidal Volume ◽  
Volume Ventilation ◽  
High Frequency Oscillatory

Pneumomediastinum (PM) is defined as the presence of abnormal gas in the mediastinum.It is a known complication of invasive mechanical ventilation and has been reported withnon-invasive ventilation. Recent studies have reported that the incidence of barotrauma islowest in post-operative patients and is highest in mechanically ventilated patients with acuterespiratory distress syndrome. The incidence has dropped with the low tidal volume ventilationtechnique. Chest x-rays can miss up to 25% of small PMs detected by computed tomographyscans of the chest. Pneumomediastinum is managed with low tidal volume ventilation withplateau pressures <30 cm H2O and treatment of the underlying lung disease. Novel ways ofventilation, such as high frequency oscillatory ventilation and asynchronous independent lungventilation, may improve ventilation in some patients.

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