Relation of the Static Compliance Curve and Positive End-expiratory Pressure to Oxygenation during One-lung Ventilation

2001 ◽  
Vol 95 (5) ◽  
pp. 1096-1102 ◽  
Author(s):  
Peter D. Slinger ◽  
Marelise Kruger ◽  
Karen McRae ◽  
Timothy Winton
Keyword(s):  
Inflection Point ◽  
Lung Ventilation ◽  
Arterial Oxygen ◽  
Positive End Expiratory Pressure ◽  
Static Compliance ◽  
One Lung Ventilation ◽  
Lower Inflection Point ◽  
Arterial Blood ◽  
Compliance Curve ◽  
The Mean

Background Positive end-expiratory pressure (PEEP) is commonly applied to the ventilated lung to try to improve oxygenation during one-lung ventilation but is an unreliable therapy and occasionally causes arterial oxygen partial pressure (PaO(2)) to decrease further. The current study examined whether the effects of PEEP on oxygenation depend on the static compliance curve of the lung to which it is applied. Methods Forty-two adults undergoing thoracic surgery were studied during stable, open-chest, one-lung ventilation. Arterial blood gases were measured during two-lung ventilation and one-lung ventilation before, during, and after the application of 5 cm H(2)O PEEP to the ventilated lung. The plateau end-expiratory pressure and static compliance curve of the ventilated lung were measured with and without applied PEEP, and the lower inflection point was determined from the compliance curve. Results Mean (+/- SD) PaO(2) values, with a fraction of inspired oxygen of 1.0, were not different during one-lung ventilation before (192 +/- 91 mmHg), during (190 +/- 90), or after ( 205 +/- 79) the addition of 5 cm H(2)O PEEP. The mean plateau end-expiratory pressure increased from 4.2 to 6.8 cm H(2)O with the application of 5 cm H(2)O PEEP and decreased to 4.5 cm H(2)O when 5 cm H(2)O PEEP was removed. Six patients showed a clinically useful (> 20%) increase in PaO(2) with 5 cm H(2)O PEEP, and nine patients had a greater than 20% decrease in PaO(2). The change in PaO(2) with the application of 5 cm H(2)O PEEP correlated in an inverse fashion with the change in the gradient between the end-expiratory pressure and the pressure at the lower inflection point (r = 0.76). The subgroup of patients with a PaO(2) during two-lung ventilation that was less than the mean (365 mmHg) and an end-expiratory pressure during one-lung ventilation without applied PEEP less than the mean were more likely to have an increase in PaO(2) when 5 cm H(2)O PEEP was applied. Conclusions The effects of the application of external 5 cm H(2)O PEEP on oxygenation during one-lung ventilation correspond to individual changes in the relation between the plateau end-expiratory pressure and the inflection point of the static compliance curve. When the application of PEEP causes the end-expiratory pressure to increase from a low level toward the inflection point, oxygenation is likely to improve. Conversely, if the addition of PEEP causes an increased inflation of the ventilated lung that raises the equilibrium end-expiratory pressure beyond the inflection point, oxygenation is likely to deteriorate.

Comparison of the lower inflection point on the static total respiratory compliance curve with outcomes in postoperative cardiothoracic patients

2001 ◽  
Vol 10 (6) ◽  
pp. 399-407 ◽  
Author(s):  
M Boyle ◽  
P Way ◽  
M Pinfold ◽  
J Lawrence
Keyword(s):  
Inflection Point ◽  
Prospective Observational Study ◽  
Recruitment Strategy ◽  
Low Flow ◽  
Positive End Expiratory Pressure ◽  
Lower Inflection Point ◽  
Respiratory Compliance ◽  
Inflection Points ◽  
Compliance Curve ◽  
The Mean

BACKGROUND: Routine use of positive end-expiratory pressure (based on the pressure at the lower inflection point on the static total respiratory compliance curve) along with a maneuver to recruit atelectatic lung has been advocated after cardiothoracic surgery. OBJECTIVES: To determine if the lower inflection point is related to outcomes in patients after sternotomy and cardiopulmonary bypass. METHOD: A prospective observational study involving estimation of the lower inflection point on the inflation pressure-volume plot obtained with a low-flow technique. Duration of intubation, length of stay, respiratory complications, and results of spirometry were compared between patients with a "high " inflection point (> or =10 cm H2O) and patients with a "low" inflection point (< or =5 cm H2O). RESULTS: Ninety-five patients were enrolled. After exclusion for incomplete data, 65 patients (49 men, 16 women; mean age, 66.1 years; SD, 9.5 years) were included. The mean lower inflection point was 6.33 cm H2O (SD, 3.4 cm H2O). A second lower inflection point was observed on 5 plots (mean, 21 cm H2O; SD, 1.4 cm H2O). Nine patients had high inflection points (mean, 13.1 cm H2O; SD, 3.0 cm H2O), and 33 had low inflection points (mean, 3.9 cm H2O; SD, 0.98 cm H2O). No outcome measures differed between groups. CONCLUSIONS: In patients with short intubation times and predictable postoperative course, general use of a lung recruitment strategy involving sustained inflations and adjustment of positive end-expiratory pressure based on the lower inflection point is difficult to justify.

scholarly journals Physiologic Evaluation of Ventilation Perfusion Mismatch and Respiratory Mechanics at Different Positive End-expiratory Pressure in Patients Undergoing Protective One-lung Ventilation

2018 ◽  
Vol 128 (3) ◽  
pp. 531-538 ◽  
Author(s):  
Savino Spadaro ◽  
Salvatore Grasso ◽  
Dan Stieper Karbing ◽  
Alberto Fogagnolo ◽  
Marco Contoli ◽  
...  
Keyword(s):  
Respiratory Mechanics ◽  
Lung Ventilation ◽  
Random Order ◽  
Driving Pressure ◽  
Shunt Fraction ◽  
Positive End Expiratory Pressure ◽  
One Lung Ventilation ◽  
Predicted Body Weight ◽  
Arterial Blood Gas ◽  
Arterial Blood

Abstract Background Arterial oxygenation is often impaired during one-lung ventilation, due to both pulmonary shunt and atelectasis. The use of low tidal volume (VT) (5 ml/kg predicted body weight) in the context of a lung-protective approach exacerbates atelectasis. This study sought to determine the combined physiologic effects of positive end-expiratory pressure and low VT during one-lung ventilation. Methods Data from 41 patients studied during general anesthesia for thoracic surgery were collected and analyzed. Shunt fraction, high V/Q and respiratory mechanics were measured at positive end-expiratory pressure 0 cm H2O during bilateral lung ventilation and one-lung ventilation and, subsequently, during one-lung ventilation at 5 or 10 cm H2O of positive end-expiratory pressure. Shunt fraction and high V/Q were measured using variation of inspired oxygen fraction and measurement of respiratory gas concentration and arterial blood gas. The level of positive end-expiratory pressure was applied in random order and maintained for 15 min before measurements. Results During one-lung ventilation, increasing positive end-expiratory pressure from 0 cm H2O to 5 cm H2O and 10 cm H2O resulted in a shunt fraction decrease of 5% (0 to 11) and 11% (5 to 16), respectively (P < 0.001). The Pao2/Fio2 ratio increased significantly only at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). Driving pressure decreased from 16 ± 3 cm H2O at a positive end-expiratory pressure of 0 cm H2O to 12 ± 3 cm H2O at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). The high V/Q ratio did not change. Conclusions During low VT one-lung ventilation, high positive end-expiratory pressure levels improve pulmonary function without increasing high V/Q and reduce driving pressure.

Set Positive End-expiratory Pressure during Protective Ventilation Affects Lung Injury

2002 ◽  
Vol 97 (3) ◽  
pp. 682-692 ◽  
Author(s):  
Muneyuki Takeuchi ◽  
Sven Goddon ◽  
Marisa Dolhnikoff ◽  
Motomu Shimaoka ◽  
Dean Hess ◽  
...  
Keyword(s):  
Inflection Point ◽  
Peep Level ◽  
Arterial Oxygen ◽  
Positive End Expiratory Pressure ◽  
Lower Inflection Point ◽  
Arterial Oxygen Partial Pressure ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Fraction Of Inspired Oxygen ◽  
Inspired Oxygen

Background The most appropriate method of determining positive end-expiratory pressure (PEEP) level during a lung protective ventilatory strategy has not been established. Methods In a lavage-injured sheep acute respiratory distress syndrome model, the authors compared the effects of three approaches to determining PEEP level after a recruitment maneuver: (1) 2 cm H(2)O above the lower inflection point on the inflation pressure-volume curve, (2) at the point of maximum curvature on the deflation pressure-volume curve, and (3) at the PEEP level that maintained target arterial oxygen partial pressure at a fraction of inspired oxygen of 0.5. Results Positive end-expiratory pressure set 2 cm H(2)O above the lower inflection point resulted in the least injury over the course of the study. PEEP based on adequate arterial oxygen partial pressure/fraction of inspired oxygen ratios had to be increased over time and resulted in higher mRNA levels for interleukin-8 and interleukin-1beta and greater tissue inflammation when compared with the other approaches. PEEP at the point of maximum curvature could not maintain eucapneia even at an increased ventilatory rate. Conclusion Although generating higher plateau pressures, PEEP levels based on pressure-volume curve analysis were more effective in maintaining gas exchange and minimizing injury than PEEP based on adequate oxygenation. PEEP at 2 cm H(2)O above the lower inflection point was most effective.

scholarly journals Effects of Positive End-Expiratory Pressure on Pulmonary Oxygenation and Biventricular Function during One-Lung Ventilation: A Randomized Crossover Study

2019 ◽  
Vol 8 (5) ◽  
pp. 740
Author(s):  
Namo Kim ◽  
Su Hyun Lee ◽  
Kwan Woong Choi ◽  
Haeyeon Lee ◽  
Young Jun Oh
Keyword(s):  
Lung Ventilation ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Arterial Oxygen ◽  
Positive End Expiratory Pressure ◽  
One Lung Ventilation ◽  
Ventricular Ejection Fraction ◽  
Lung Cancer Patients ◽  
Biventricular Function ◽  
Echocardiographic Parameters

Although the application of positive end-expiratory pressure (PEEP) can alter cardiopulmonary physiology during one-lung ventilation (OLV), these changes have not been clearly elucidated. This study assessed the effects of different levels of PEEP on biventricular function, as well as pulmonary oxygenation during OLV. Thirty-six lung cancer patients received one PEEP combination of six sequences, consisting of 0 (PEEP_0), 5 (PEEP_5), and 10 cmH2O (PEEP_10), using a crossover design during OLV. The ratio of arterial oxygen partial pressure to inspired oxygen fraction (P/F ratio), systolic and diastolic echocardiographic parameters were measured at 20 min after the first, second, and third PEEP. P/F ratio at PEEP_5 was significantly higher compared to PEEP_0 (p = 0.014), whereas the P/F ratio at PEEP_10 did not show significant differences compared to PEEP_0 or PEEP_5. Left ventricular ejection fraction (LV EF) and right ventricular fractional area change (RV FAC) at PEEP_10 (EF, p < 0.001; FAC, p = 0.001) were significantly lower compared to PEEP_0 or PEEP_5. RV E/E’ (p = 0.048) and RV myocardial performance index (p < 0.001) at PEEP_10 were significantly higher than those at PEEP_0 or PEEP_5. In conclusion, increasing PEEP to 10 cmH2O decreased biventricular function, especially on RV function, with no further improvement on oxygenation compared to PEEP 5 cmH2O during OLV.

Biologically Variable Ventilation Improves Oxygenation and Respiratory Mechanics during One-lung Ventilation

2006 ◽  
Vol 105 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Michael C. McMullen ◽  
Linda G. Girling ◽  
M Ruth Graham ◽  
W Alan C. Mutch
Keyword(s):  
Tidal Volume ◽  
Respiratory Mechanics ◽  
Lung Ventilation ◽  
Group Effect ◽  
Shunt Fraction ◽  
Static Compliance ◽  
One Lung Ventilation ◽  
Time Interaction ◽  
Variable Ventilation ◽  
Dead Space Ventilation

Background Hypoxemia is common during one-lung ventilation (OLV). Atelectasis contributes to the problem. Biologically variable ventilation (BVV), using microprocessors to reinstitute physiologic variability to respiratory rate and tidal volume, has been shown to be advantageous over conventional monotonous control mode ventilation (CMV) in improving oxygenation during the period of lung reinflation after OLV in an experimental model. Here, using a porcine model, the authors compared BVV with CMV during OLV to assess gas exchange and respiratory mechanics. Methods Eight pigs (25-30 kg) were studied in each of two groups. After induction of anesthesia-tidal volume 12 ml/kg with CMV and surgical intervention-tidal volume was reduced to 9 ml/kg. OLV was initiated with an endobronchial blocker, and the animals were randomly allocated to either continue CMV or switch to BVV for 90 min. After OLV, a recruitment maneuver was undertaken, and both lungs were ventilated for a further 60 min. At predetermined intervals, hemodynamics, respiratory gases (arterial, venous, and end-tidal samples) and mechanics (airway pressures, static and dynamic compliances) were measured. Derived indices (pulmonary vascular resistance, shunt fraction, and dead space ventilation) were calculated. Results By 15 min of OLV, arterial oxygen tension was greater in the BVV group (group x time interaction, P = 0.003), and shunt fraction was lower with BVV from 30 to 90 min (group effect, P = 0.0004). From 60 to 90 min, arterial carbon dioxide tension was lower with BVV (group x time interaction, P = 0.0001) and dead space ventilation was less from 60 to 90 min (group x time interaction, P = 0.0001). Static compliance was greater by 60 min of BVV and remained greater during return to ventilation of both lungs (group effect, P = 0.0001). Conclusions In this model of OLV, BVV resulted in superior gas exchange and respiratory mechanics when compared with CMV. Improved static compliance persisted with restoration of two-lung ventilation.

scholarly journals Effect of Thoracic Epidural Anesthesia with Different Concentrations of Ropivacaine on Arterial Oxygenation during One-lung Ventilation

2010 ◽  
Vol 112 (5) ◽  
pp. 1146-1154 ◽  
Author(s):  
Yajun Xu ◽  
Zhiming Tan ◽  
Shilai Wang ◽  
Haijun Shao ◽  
Xuqin Zhu
Keyword(s):  
Epidural Anesthesia ◽  
Arterial Oxygen Tension ◽  
Lung Ventilation ◽  
Saline Group ◽  
Lung Surgery ◽  
Thoracic Epidural Anesthesia ◽  
Arterial Oxygen ◽  
One Lung Ventilation ◽  
Thoracic Epidural ◽  
Double Blinded

Background Thoracic epidural anesthesia can contribute to facilitate the fast-track approach in lung surgery. However, data regarding the effects of thoracic epidural anesthesia on oxygenation during one-lung ventilation (OLV) are scarce and contradictory. Therefore, the authors conducted a prospective, randomized, double-blinded trial in patients undergoing lung surgery under spectral entropy-guided intravenous anesthesia to evaluate the effects of thoracic epidural anesthesia with different concentrations of ropivacaine on oxygenation, shunt fraction (Qs/Qt) during OLV, and maintenance doses of propofol. Methods One hundred twenty patients scheduled for lung surgery were randomly divided into four groups to epidurally receive saline (Group S), 0.25% (Group R0.25), 0.50% (Group R0.50), and 0.75% (Group R0.75) ropivacaine. Ropivacaine was administered intraoperatively (6-8 ml of first bolus + 5 ml/h infusion). Arterial oxygen tension (Pao2) and Qs/Qt were measured before, during, and after OLV. Results Pao2 was significantly lower in Group R0.75 compared with that in Group S and Group R0.25 10 min (170 +/- 61 vs. 229 +/- 68 mmHg, P = 0.01; 170 +/- 61 vs. 223 +/- 70 mmHg, P = 0.03) and 20 min after OLV (146 +/- 52 vs. 199 +/- 68 mmHg, P = 0.009; 146 +/- 52 vs. 192 +/- 67 mmHg, P = 0.03). During OLV, Qs/Qt was significantly higher in Group R0.75 compared with that in Group S and Group R0.25 (P &lt; 0.05). Maintenance doses of propofol were significantly lower in Group R0.75. Vasopressor requirements were higher in Group R0.75. Conclusion A decrease in oxygenation during OLV occurred only at the highest dose of epidural local anesthetic and not at lower doses. Higher doses of epidural medication required less propofol and more vasopressors.

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