scholarly journals Maintenance of end-expiratory recruitment with increased respiratory rate after saline-lavage lung injury

2007 ◽  
Vol 102 (1) ◽  
pp. 331-339 ◽  
Author(s):  
Rebecca S. Syring ◽  
Cynthia M. Otto ◽  
Rebecca E. Spivack ◽  
Klaus Markstaller ◽  
James E. Baumgardner
Keyword(s):  
Cardiac Output ◽  
Lung Injury ◽  
Respiratory Rate ◽  
Pressure Control ◽  
Plateau Pressure ◽  
Control Mode ◽  
Intrinsic Peep ◽  
Mixed Venous Saturation ◽  
Mixed Venous ◽  
Saline Lavage

Cyclical recruitment of atelectasis with each breath is thought to contribute to ventilator-associated lung injury. Extrinsic positive end-expiratory pressure (PEEPe) can maintain alveolar recruitment at end exhalation, but PEEPe depresses cardiac output and increases overdistension. Short exhalation times can also maintain end-expiratory recruitment, but if the mechanism of this recruitment is generation of intrinsic PEEP (PEEPi), there would be little advantage compared with PEEPe. In seven New Zealand White rabbits, we compared recruitment from increased respiratory rate (RR) to recruitment from increased PEEPe after saline lavage. Rabbits were ventilated in pressure control mode with a fraction of inspired O2 (FiO2) of 1.0, inspiratory-to-expiratory ratio of 2:1, and plateau pressure of 28 cmH2O, and either 1) high RR ( 24 ) and low PEEPe (3.5) or 2) low RR ( 7 ) and high PEEPe ( 14 ). We assessed cyclical lung recruitment with a fast arterial Po2 probe, and we assessed average recruitment with blood gas data. We measured PEEPi, cardiac output, and mixed venous saturation at each ventilator setting. Recruitment achieved by increased RR and short exhalation time was nearly equivalent to recruitment achieved by increased PEEPe. The short exhalation time at increased RR, however, did not generate PEEPi. Cardiac output was increased on average 13% in the high RR group compared with the high PEEPe group ( P < 0.001), and mixed venous saturation was consistently greater in the high RR group ( P < 0.001). Prevention of end-expiratory derecruitment without increased end-expiratory pressure suggests that another mechanism, distinct from intrinsic PEEP, plays a role in the dynamic behavior of atelectasis.

Mechanical Power and Development of Ventilator-induced Lung Injury

2016 ◽  
Vol 124 (5) ◽  
pp. 1100-1108 ◽  
Author(s):  
Massimo Cressoni ◽  
Miriam Gotti ◽  
Chiara Chiurazzi ◽  
Dario Massari ◽  
Ilaria Algieri ◽  
...  
Keyword(s):  
Lung Injury ◽  
Respiratory Rate ◽  
Transpulmonary Pressure ◽  
Lung Parenchyma ◽  
Plateau Pressure ◽  
Mechanical Power ◽  
Lung Edema ◽  
Lung Weight ◽  
Ventilator Induced Lung Injury ◽  
Power Threshold

Abstract Background The ventilator works mechanically on the lung parenchyma. The authors set out to obtain the proof of concept that ventilator-induced lung injury (VILI) depends on the mechanical power applied to the lung. Methods Mechanical power was defined as the function of transpulmonary pressure, tidal volume (TV), and respiratory rate. Three piglets were ventilated with a mechanical power known to be lethal (TV, 38 ml/kg; plateau pressure, 27 cm H2O; and respiratory rate, 15 breaths/min). Other groups (three piglets each) were ventilated with the same TV per kilogram and transpulmonary pressure but at the respiratory rates of 12, 9, 6, and 3 breaths/min. The authors identified a mechanical power threshold for VILI and did nine additional experiments at the respiratory rate of 35 breaths/min and mechanical power below (TV 11 ml/kg) and above (TV 22 ml/kg) the threshold. Results In the 15 experiments to detect the threshold for VILI, up to a mechanical power of approximately 12 J/min (respiratory rate, 9 breaths/min), the computed tomography scans showed mostly isolated densities, whereas at the mechanical power above approximately 12 J/min, all piglets developed whole-lung edema. In the nine confirmatory experiments, the five piglets ventilated above the power threshold developed VILI, but the four piglets ventilated below did not. By grouping all 24 piglets, the authors found a significant relationship between the mechanical power applied to the lung and the increase in lung weight (r2 = 0.41, P = 0.001) and lung elastance (r2 = 0.33, P &lt; 0.01) and decrease in Pao2/Fio2 (r2 = 0.40, P &lt; 0.001) at the end of the study. Conclusion In piglets, VILI develops if a mechanical power threshold is exceeded.

scholarly journals The Perspective of the Intensivist on Inotropes and Postoperative Care Following Pediatric Heart Surgery: An International Survey and Systematic Review of the Literature

2017 ◽  
Vol 9 (1) ◽  
pp. 10-21 ◽  
Author(s):  
Peter P. Roeleveld ◽  
J. C. A. de Klerk
Keyword(s):  
Systematic Review ◽  
Cardiac Output ◽  
Congenital Heart ◽  
Heart Surgery ◽  
Congenital Heart Surgery ◽  
Sufficient Evidence ◽  
Infrared Spectrometry ◽  
Review Of The Literature ◽  
Mixed Venous Saturation ◽  
Mixed Venous

Introduction: Inotropes are frequently being used in children undergoing heart surgery to prevent or treat low cardiac output syndrome (LCOS). There is only limited evidence that inotropes actually positively influence postoperative outcome. Our aim was to describe the current international practice variation in the use of inotropes following congenital heart surgery. Methods: We developed an online survey regarding the postoperative use of inotropes. We sent an invitation to all 197 registered members of the Pediatric Cardiac Intensive Care Society (PCICS) to participate in the survey. We also performed a systematic review of the literature. Results: Ninety-eight people (50%) responded, representing 62 international centers. Milrinone is routinely used perioperatively by 90 respondents (97%). Adrenaline/epinephrine is routinely used by 43%, dopamine by 36%, dobutamine by 11%, and levosimendan by 6%. Steroids are used routinely by 54% before initiating cardiopulmonary bypass. Vasopressin is used by 44% of respondents. The development of LCOS is monitored with lactate in 99% of respondents, physical examination (98%), intermittent mixed venous saturation (76%), continuous mixed venous saturation (13%), echocardiography (53%), core–peripheral temperature gap (29%), near-infrared spectrometry (25%), and 4% use cardiac output monitors (PiCCO, USCOM). To improve cardiac output, 42% add/increase milrinone, 37% add adrenaline, and 15% add dopamine. Rescue therapy is titrated individually, based on the patients’ pathophysiology. A systematic review of the literature failed to show compelling evidence with regard to the benefit of inotropes. Conclusions: Despite the lack of sufficient evidence, milrinone is used by the vast majority of caregivers following congenital heart surgery.

Effects of Respiratory Rate, Plateau Pressure, and Positive End-Expiratory Pressure on PaO2Oscillations after Saline Lavage

2002 ◽  
Vol 166 (12) ◽  
pp. 1556-1562 ◽  
Author(s):  
James E. Baumgardner ◽  
Klaus Markstaller ◽  
Birgit Pfeiffer ◽  
Marcus Doebrich ◽  
Cynthia M. Otto
Keyword(s):  
Respiratory Rate ◽  
Plateau Pressure ◽  
Positive End Expiratory Pressure ◽  
Saline Lavage

Perforation of the right ventricle by a pulmonary artery catheter that continues to measure cardiac output and mixed venous saturation

2005 ◽  
Vol 17 (2) ◽  
pp. 124-127 ◽  
Author(s):  
Kuan-Chih Chuang ◽  
Albert Kok-Mao Lan ◽  
Hsiang Ning Luk ◽  
Chi-Shien Wang ◽  
Chia-Jung Huang ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Pulmonary Artery ◽  
Right Ventricle ◽  
Pulmonary Artery Catheter ◽  
Mixed Venous Saturation ◽  
The Right ◽  
Mixed Venous

In Vivo Comparison of Two Mixed Venous Saturation Catheters

1987 ◽  
Vol 66 (3) ◽  
pp. 373-375 ◽  
Author(s):  
Andrew Gettinger ◽  
Michael C. DeTraglia ◽  
D. David Glass
Keyword(s):  
Mixed Venous Saturation ◽  
Mixed Venous

Respiratory measurements of cardiac output: from elegant idea to useful test

2004 ◽  
Vol 96 (2) ◽  
pp. 428-437 ◽  
Author(s):  
Gabriel Laszlo
Keyword(s):  
Cardiac Output ◽  
Human Subjects ◽  
Venous Blood ◽  
The Body ◽  
Mixed Venous Blood ◽  
Indirect Determination ◽  
Arterial Blood ◽  
Pulmonary Capillary ◽  
Pulmonary Arterial ◽  
Mixed Venous

The measurement of cardiac output was first proposed by Fick, who published his equation in 1870. Fick's calculation called for the measurement of the contents of oxygen or CO2 in pulmonary arterial and systemic arterial blood. These values could not be determined directly in human subjects until the acceptance of cardiac catheterization as a clinical procedure in 1940. In the meanwhile, several attempts were made to perfect respiratory methods for the indirect determination of blood-gas contents by respiratory techniques that yielded estimates of the mixed venous and pulmonary capillary gas pressures. The immediate uptake of nonresident gases can be used in a similar way to calculate cardiac output, with the added advantage that they are absent from the mixed venous blood. The fact that these procedures are safe and relatively nonintrusive makes them attractive to physiologists, pharmacologists, and sports scientists as well as to clinicians concerned with the physiopathology of the heart and lung. This paper outlines the development of these techniques, with a discussion of some of the ways in which they stimulated research into the transport of gases in the body through the alveolar membrane.

scholarly journals Product of driving pressure and respiratory rate for predicting weaning outcomes

2021 ◽  
Vol 49 (5) ◽  
pp. 030006052110100
Author(s):  
Ju Gong ◽  
Bibo Zhang ◽  
Xiaowen Huang ◽  
Bin Li ◽  
Jian Huang
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory Rate ◽  
Spontaneous Breathing ◽  
Spontaneous Breathing Trial ◽  
Plateau Pressure ◽  
Driving Pressure ◽  
Failure Group ◽  
Rapid Shallow Breathing Index ◽  
Weaning Failure ◽  
Shallow Breathing

Objective Clinicians cannot precisely determine the time for withdrawal of ventilation. We aimed to evaluate the performance of driving pressure (DP)×respiratory rate (RR) to predict the outcome of weaning. Methods Plateau pressure (Pplat) and total positive end-expiratory pressure (PEEPtot) were measured during mechanical ventilation with brief deep sedation and on volume-controlled mechanical ventilation with a tidal volume of 6 mL/kg and a PEEP of 0 cmH2O. Pplat and PEEPtot were measured by patients holding their breath for 2 s after inhalation and exhalation, respectively. DP was determined as Pplat minus PEEPtot. The rapid shallow breathing index was measured from the ventilator. The highest RR was recorded within 3 minutes during a spontaneous breathing trial. Patients who tolerated a spontaneous breathing trial for 1 hour were extubated. Results Among the 105 patients studied, 44 failed weaning. During ventilation withdrawal, DP×RR was 136.7±35.2 cmH2O breaths/minute in the success group and 230.2±52.2 cmH2O breaths/minute in the failure group. A DP×RR index >170.8 cmH2O breaths/minute had a sensitivity of 93.2% and specificity of 88.5% to predict failure of weaning. Conclusions Measurement of DP×RR during withdrawal of ventilation may help predict the weaning outcome. A high DP×RR increases the likelihood of weaning failure. Statement: This manuscript was previously posted as a preprint on Research Square with the following link: https://www.researchsquare.com/article/rs-15065/v3 and DOI: 10.21203/rs.2.24506/v3

Estimation of ventilation-perfusion inequality by inert gas elimination without arterial sampling

1985 ◽  
Vol 59 (2) ◽  
pp. 376-383 ◽  
Author(s):  
P. D. Wagner ◽  
C. M. Smith ◽  
N. J. Davies ◽  
R. D. McEvoy ◽  
G. E. Gale
Keyword(s):  
Cardiac Output ◽  
Venous Blood ◽  
Inert Gas ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Arterial Access ◽  
Arterial Blood ◽  
Potential Applications ◽  
Clinical Interest ◽  
Mixed Venous

Estimation of ventilation-perfusion (VA/Q) inequality by the multiple inert gas elimination technique requires knowledge of arterial, mixed venous, and mixed expired concentrations of six gases. Until now, arterial concentrations have been directly measured and mixed venous levels either measured or calculated by mass balance if cardiac output was known. Because potential applications of the method involve measurements over several days, we wished to determine whether inert gas levels in peripheral venous blood ever reached those in arterial blood, thus providing an essentially noninvasive approach to measuring VA/Q mismatch that could be frequently repeated. In 10 outpatients with chronic obstructive pulmonary disease, we compared radial artery (Pa) and peripheral vein (Pven) levels of the six gases over a 90-min period of infusion of the gases into a contralateral forearm vein. We found Pven reached 90% of Pa by approximately 50 min and 95% of Pa by 90 min. More importantly, the coefficient of variation at 50 min was approximately 10% and at 90 min 5%, demonstrating acceptable intersubject agreement by 90 min. Since cardiac output is not available without arterial access, we also examined the consequences of assuming values for this variable in calculating mixed venous levels. We conclude that VA/Q features of considerable clinical interest can be reliably identified by this essentially noninvasive approach under resting conditions stable over a period of 1.5 h.

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