Using Conventional Infant Ventilators at Unconventional Rates

PEDIATRICS ◽  
1984 ◽  
Vol 74 (4) ◽  
pp. 487-492 ◽  
Author(s):  
Stephen J. Boros ◽  
Dennis R. Bing ◽  
Mark C. Mammel ◽  
Erik Hagen ◽  
Margaret J. Gordon
Keyword(s):  
Tidal Volume ◽  
Airway Pressure ◽  
Important Determinant ◽  
Peak Inspiratory Pressure ◽  
Lung Compliance ◽  
Minute Volume ◽  
Inspiratory Pressure ◽  
Positive End Expiratory Pressure ◽  
Inspiratory Time ◽  
Pressure Monitor

The effect of progressive increases in ventilator rate on delivered tidal and minute volumes, and the effect of changing peak inspiratory pressure (Pmax), positive end-expiratory pressure (PEEP), and inspiration to expiration (I:E) ratio at different ventilator rates were examined. Five different continuous-flow, time-cycled, pressure-preset infant ventilators were studied using a pneumotachograph, an airway pressure monitor, and a lung simulator. As rates increased from 10 to 150 breaths per minute, tidal volume stayed constant until 25 to 30 breaths per minute; then progessively decreased. In all, tidal volume began to decrease when proximal airway pressure waves lost inspiratory pressure plateaus. As rates increased, minute volume increased until 75 breaths per minute, then leveled off, then decreased. Substituting helium for O2 increased the ventilator rate at which this minute volume plateau effect occurred. Increasing peak inspiratory pressure consistently increased tidal volume. Increasing positive end-expiratory pressure decreased tidal volume. At rates less than 75 breaths per minute, inspiratory time (inspiration to expiration ratio) had little effect on delivered volume. At rates greater than 75 breaths per minute, inspiratory time became an important determinant of minute volume. For any given combination of lung compliance and airway resistance: (1) there is a maximum ventilator rate beyond which tidal volume progressively decreases and another maximum ventilator rate beyond which minute volume progressively decreases; (2) at slower rates, delivered volumes are determined primarily by changes in proximal airway pressures; (3) at very rapid rates, inspiratory time becomes a key determinant of delivered volume.

Determinants of gas flow through a bronchopleural fistula

1989 ◽  
Vol 67 (4) ◽  
pp. 1591-1596 ◽  
Author(s):  
M. C. Walsh ◽  
W. A. Carlo
Keyword(s):  
Airway Pressure ◽  
Gas Flow ◽  
Bronchopleural Fistula ◽  
Peak Inspiratory Pressure ◽  
Intrathoracic Pressure ◽  
Transpulmonary Pressure ◽  
Inspiratory Pressure ◽  
Positive End Expiratory Pressure ◽  
Inspiratory Time ◽  
Mean Airway Pressure

To assess the determinants of bronchopleural fistula (BPF) flow, we used a surgically created BPF to study 15 anesthetized intubated mechanically ventilated New Zealand White rabbits. Mean airway pressure and intrathoracic pressure were evaluated independently. Mean airway pressure was varied (8, 10, or 12 cmH2O) by independent manipulations of either peak inspiratory pressure, positive end-expiratory pressure, or inspiratory time. Intrathoracic pressure was varied from 0 to -40 cmH2O. BPF flow varied directly with mean airway pressure (P less than 0.001). However, at constant mean airway pressure, BPF flow was not influenced independently by changes in peak inspiratory pressure, positive end-expiratory pressure, or inspiratory time. Resistance of the BPF increased as intrathoracic pressure became more negative. Despite increased resistance, BPF flow also increased. BPF resistance was constant over the range of mean airway (P less than 0.01) pressures investigated. Our data document the influence of mean airway pressure and intrathoracic pressure on BPF flow and suggest that manipulations which reduce transpulmonary pressure will decrease BPF flow.

scholarly journals PEEP and CPAP

1986 ◽  
Vol 14 (3) ◽  
pp. 236-250 ◽  
Author(s):  
A. W. Duncan ◽  
T. E. Oh ◽  
D. R. Hillman
Keyword(s):  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Work Of Breathing ◽  
Lung Compliance ◽  
Raised Intracranial Pressure ◽  
Positive End Expiratory Pressure ◽  
Pulmonary Barotrauma ◽  
Endotracheal Tubes ◽  
Wide Range ◽  
Residual Capacity

Positive end-expiratory pressure (PEEP) maintains airway pressure above atmospheric at the end of expiration, and may be used with mechanical ventilation or spontaneous breathing. CPAP, or continuous positive airway pressure, refers to spontaneous ventilation with a positive airway pressure being maintained throughout the whole respiratory cycle. PEEP/CPAP primarily improves oxygenation by increasing functional residual capacity, and may increase lung compliance and decrease the work of breathing. PEEP/CPAP may be applied using endotracheal tubes, nasal masks or prongs, or face masks or chambers to treat a wide range of adult and paediatric respiratory disorders. Complications associated with their use relate to the pressures applied and include pulmonary barotrauma, decreased cardiac output and raised intracranial pressure.

Ventilation with Constant Versus Decelerating Inspiratory Flow in Experimentally Induced Acute Respiratory Failure

1996 ◽  
Vol 84 (4) ◽  
pp. 882-889. ◽  
Author(s):  
Agneta M. Markstrom ◽  
Michael Lichtwarck-Aschoff ◽  
Bjorn A. Svensson ◽  
K. Anders Nordgren ◽  
Ulf H. Sjostrand
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Tidal Volume ◽  
Airway Pressure ◽  
Arterial Oxygen Tension ◽  
Inspiratory Flow ◽  
Arterial Oxygen ◽  
Positive End Expiratory Pressure ◽  
Residual Capacity ◽  
Inspiratory Flow Pattern

Background Recognition of the potential for ventilator-associated lung injury has renewed the debate on the importance of the inspiratory flow pattern. The aim of this study was to determine whether a ventilatory pattern with decelerating inspiratory flow, with the major part of the tidal volume delivered early, would increase functional residual capacity at unchanged (or even reduced) inspiratory airway pressures and improve gas exchange at different positive end-expiratory pressure levels. Methods Surfactant depletion was induced by repeated bronchoalveolar lavage in 13 anesthetized piglets. Decelerating and constant inspiratory flow ventilation was applied at positive end-expiratory pressure levels of 22, 17, 13, 9, and 4 cm H(2)O. Tidal volume, inspiration-to-expiration ratio, and ventilatory frequency were kept constant. Airway pressures, gas exchange, functional residual capacity (using a wash-in/washout method with sulfurhexafluoride), central hemodynamics, and extravascular lung water (using the thermo-dye-indicator dilution technique) were measured. Results Decelerating inspiratory flow yielded a lower arterial carbon dioxide tension compared to constant flow, that is, it improved alveolar ventilation. There were no differences between the flow patterns regarding end-inspiratory occlusion airway pressure, end-inspiratory lung volume, static compliance, or arterial oxygen tension. No differences were seen in hemodynamics and oxygen delivery. Conclusions The decelerating inspiratory flow pattern increased carbon dioxide elimination, without any reduction of inspiratory airway pressure or apparent improvement in arterial oxygen tension. It remains to be established whether these differences are sufficiently pronounced to justify therapeutic consideration.

scholarly journals Impact of lung compliance on neurological outcome in patients with acute respiratory distress syndrome following out-of-hospital cardiac arrest

2020 ◽  
Author(s):  
June-Sung Kim ◽  
Youn-Jung Kim ◽  
Muyeol Kim ◽  
Seung Mok Ryoo ◽  
Chang Hwan Sohn ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Neurological Outcome ◽  
Distress Syndrome ◽  
Peak Inspiratory Pressure ◽  
Lung Compliance ◽  
Inspiratory Pressure ◽  
Neurologic Outcome ◽  
Hospital Cardiac Arrest

Abstract Background Acute respiratory distress syndrome (ARDS) following cardiac arrest is common and associated with in-hospital mortality. We aimed to investigate whether lung compliance during targeted temperature management is associated with neurological outcome in patients with ARDS after out-of-hospital cardiac arrest (OHCA).Methods This observational study was conducted in the emergency intensive care unit from January 2011 to April 2019 using data from a prospective patient registry. Adult patients (age ≥18 years) who survived non-traumatic OHCA and subsequently developed ARDS based on the Berlin definition were included. Mechanical ventilator parameters such as peak inspiratory pressure, tidal volume, minute ventilation, positive end expiratory pressure, and compliance were recorded for 7 days or until death, and categorized as maximum, median, and minimum. The primary outcome was favorable neurological outcome defined as Cerebral Performance Category score 1 or 2 at hospital discharge.Results Of 246 OHCA survivors, 119 (48.4%) patients developed ARDS. A favorable neurologic outcome was observed in 23 (19.3%). Patients with favorable outcome had significantly higher lung compliance (38.6 cm H 2 O vs 27.5 cm H 2 O), lower inspiratory pressure (12.0 cm H 2 O vs 16.0 cm H 2 O), and lower peak inspiratory pressure (17.0 cm H 2 O vs 21.0 cm H 2 O) than those with poor neurologic outcome (all P <0.01). In time-dependent cox regression models, all maximum (hazard ratio [HR] 1.05, 95% confidence interval [CI] 1.03-1.08), minimum (HR 1.08, 95% CI 1.04 – 1.12), and median (HR 1.06, 95% CI 1.03-1.10) compliances were independently associated with good neurologic outcome. Median compliance > 31.4 mL/cm H 2 O at day 1 had the highest area under the receiver operating characteristic curve (0.732) with positive predictive value of 90%.Conclusion Lung compliance may be an early predictor of neurologic intact survival in patients with ARDS following cardiac arrest.

scholarly journals Can you calculate the total respiratory, lung, and chest wall respiratory mechanics?

2020 ◽  
Vol 1 (1) ◽  
pp. 24-26
Author(s):  
Mia Shokry ◽  
Kimiyo Yamasaki ◽  
Ehab Daoud
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Chest Wall ◽  
Airway Pressure ◽  
Respiratory Mechanics ◽  
Peak Inspiratory Pressure ◽  
Esophageal Pressure ◽  
Horizontal Line ◽  
Pulmonary Pressure ◽  
Volume Controlled

Figure: Waveforms for a patient undergoing mechanical ventilation with volume controlled mode. Tidal Volume of 500 ml, PEEP 15, Constant inspiratory flow of 45 l/min A: Airway pressure in cmH2O, B: Esophageal pressure in cmH2O, C: Trans-pulmonary pressure in cmH2O, D: Flow in l/min, E: Tidal volume in ml Red dashed horizontal line: values at end of expiratory occlusion maneuver, White solid horizontal line: values at end of inspiratory occlusion maneuver, Green dashed horizontal line: values during peak inspiratory pressure.

scholarly journals Evaluation of peak inspiratory pressure, tidal volume and respiratory rate during ventilation of premature lambs using a self-inflating bag

2006 ◽  
Vol 82 (4) ◽  
pp. 279-283 ◽  
Author(s):  
Jefferson G. Resende ◽  
Carlos A. M. Zaconeta ◽  
Antônio C. P. Ferreira ◽  
César A. M. Silva ◽  
Marcelo P. Rodrigues ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Peak Inspiratory Pressure ◽  
Inspiratory Pressure

scholarly journals Comparison of Positive End-Expiratory Pressure versus Tidal Volume-Induced Ventilator-Driven Alveolar Recruitment Maneuver in Robotic Prostatectomy: A Randomized Controlled Study

2021 ◽  
Vol 10 (17) ◽  
pp. 3921
Author(s):  
Kangha Jung ◽  
Sojin Kim ◽  
Byung Jun Kim ◽  
MiHye Park
Keyword(s):  
Laparoscopic Surgery ◽  
Tidal Volume ◽  
Supine Position ◽  
Recruitment Maneuver ◽  
Lung Compliance ◽  
Robotic Prostatectomy ◽  
Alveolar Recruitment ◽  
Driving Pressure ◽  
Positive End Expiratory Pressure ◽  
Alveolar Recruitment Maneuver

Background: We evaluated the pulmonary effects of two ventilator-driven alveolar recruitment maneuver (ARM) methods during laparoscopic surgery. Methods: Sixty-four patients undergoing robotic prostatectomy were randomized into two groups: incrementally increasing positive end-expiratory pressure in a stepwise manner (PEEP group) versus tidal volume (VT group). We performed each ARM after induction of anesthesia in the supine position (T1), after pneumoperitoneum in the Trendelenburg position (T2), and after peritoneum desufflation in the supine position (T3). The primary outcome was change in end-expiratory lung impedance (EELI) before and 5 min after ARM at T3, measured by electrical impedance tomography. Results: The PEEP group showed significantly higher increasing EELI 5 min after ARM than the VT group at T1 and T3 (median [IQR] 460 [180,800] vs. 200 [80,315], p = 0.002 and 280 [170,420] vs. 95 [55,175], p = 0.004, respectively; PEEP group vs. VT group). The PEEP group showed significantly higher lung compliance and lower driving pressure at T1 and T3. However, there was no significant difference in EELI change, lung compliance, or driving pressure after ARM at T2. Conclusions: The ventilator-driven ARM by the increasing PEEP method led to greater improvements in lung compliance at the end of laparoscopic surgery than the increasing VT method.

Activation of pulmonary rapidly adapting receptors does not induce bronchoconstriction in dogs

1996 ◽  
Vol 80 (1) ◽  
pp. 233-239 ◽  
Author(s):  
J. Yu ◽  
S. Mink
Keyword(s):  
Airway Pressure ◽  
Muscle Tone ◽  
Lung Compliance ◽  
The Other ◽  
Vagal Afferents ◽  
Reflex Response ◽  
Positive End Expiratory Pressure ◽  
Central Response ◽  
Pressure Swing ◽  
Stimulation Of

Activation of pulmonary rapidly adapting receptors (RARs) is believed to constrict airways by a vagally mediated reflex. We tested this hypothesis in dogs anesthetized with sufentanil citrate. We ventilated both lungs separately at a positive end-expiratory pressure of 4 cmH2O. We stimulated RARs in one lung under three different conditions: 1) deflation of the lung; 2) decrease in lung compliance; and 3) aerosolization of methacholine. We monitored the airway pressure in the nonstimulated lung as an index for airway muscle tone and could not detect increases in the pressure swing under these conditions. On the other hand, electrical stimulation of the distal end of cervical vagus nerve increased the pressure swing bilaterally (ipsilateral dominant), suggesting that reflex response could be detected in our preparation. Moreover, deflation (or inflation) of either lung increased (or suppressed) diaphragmatic activity. The results indicate intact vagal afferents and central response in our preparation. We conclude that activation of RARs located below the carina does not induce bronchoconstriction by a centrally mediated reflex. If any effect is present, it appears to be small.

scholarly journals Effect of Pre-emptive Alveolar Recruitment Strategy before Pneumoperitoneum on Arterial Oxygenation during Laparoscopic Hysterectomy

2009 ◽  
Vol 37 (4) ◽  
pp. 593-597 ◽  
Author(s):  
H.-P. Park ◽  
J.-W. Hwang ◽  
Y. B. Kim ◽  
Y.-T. Jeon ◽  
S.-H. Park ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Peak Inspiratory Pressure ◽  
Laparoscopic Hysterectomy ◽  
Alveolar Recruitment ◽  
Recruitment Strategy ◽  
Arterial Oxygen ◽  
Arterial Oxygenation ◽  
Positive End Expiratory Pressure ◽  
Randomised Controlled ◽  
To Receive

In a randomised, controlled, single-blind trial, we examined the effect of a pre-emptive alveolar recruitment strategy on arterial oxygenation during subsequent pneumoperitoneum. After intubation, 50 patients were randomly allocated to receive either tidal volume 10 ml/kg with no positive end-expiratory pressure (group C) or alveolar recruitment strategy of 10 manual breaths with peak inspiratory pressure of 40 cmH2O plus positive end-expiratory pressure of 15 cmH2O before gas insufflation (group P). During pneumoperitoneum, group P was ventilated with the same setting as group C (FiO2=0.35, tidal volume 10 ml/kg). PaO2 measured during peumoperitoneum was higher in group P than in group C (166∓32 mmHg vs 145∓34 mmHg at 15 minutes, P=0.028, 155∓30 mmHg vs 136∓32 mmHg at 30 minutes, P=0.035). Alveolar-arterial oxygen gradient in group P increased less after gas insufflation (13∓9 to 60∓34 mmHg vs 10∓9 to 37∓31 mmHg, P=0.013). We conclude that the alveolar recruitment strategy we applied before insufflation of the peritoneal cavity may improve oxygenation during laparoscopic hysterectomy.

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