Application Of PEEP Research Articles

10 cm H2O PEEP application in laparoscopic surgery and cerebral oxygenation: a comparative study with INVOS and FORESIGHT

In the present study, changes in hemodynamic parameters and cerebral oxygen saturation (rSO2) associated with 10 cm H2O PEEP application were investigated, which is assumed beneficial for the respiratory functions and oxygenation during laparoscopic cholecystectomy (LC) applied at 30° head-up left side position. Data gathered via two devices, namely INVOS and FORESIGHT, were compared. After both the ethics committee approval from the hospital and patients' written consents were obtained, patients undergoing elective laparoscopic surgery (only ASA I-II) were randomly divided into two groups (Clinical trials protocol NCT02071550). Sensors of INVOS and FORESIGHT devices were placed on the right side at the forehead region. In total, 11 evaluation periods were formed, namely pre-induction (1st period), post-induction (2nd period), abdominal insufflation outset (3rd period), post-insufflation at 5-min intervals (4th, 5th, 6th, 7th, and 8th period), at the end of insufflation (9th period), at the end of operation (10th period), and at the end of anesthesia (11th period). While one of the groups did not receive PEEP (ZEEP group), the other group received 10 cm H2O along with abdominal insufflation (PEEP group). Demographic data, hemodynamic values, and rSO2 values were recorded for both groups at all 11 periods. A total of 44 patients in two groups, each group containing 22 individuals, were included in the study. Systolic, diastolic, and mean arterial pressures, etCO2 and SO2 values, and demographic data were found to be similar in both groups. Heart rate was observed to be higher in the PEEP group starting with the PEEP administration. INVOS rSO2 values were found similar in both groups. However, FORESIGHT rSO2 values were found to be higher in the PEEP group compared to the ZEEP group. No patient had cerebral desaturation in both groups throughout the study. Application of PEEP with 10 cm H2O during abdominal insufflation could increase the rSO2 value and heart rate in patients undergoing laparoscopic cholecystectomy. However, all changes observed were within normal limits. FORESIGHT device yielded more compatible results with hemodynamic data compared to INVOS.

Intraoperative positive end-expiratory pressure evaluation using the intratidal compliance-volume profile

Lung-protective mechanical ventilation during general surgery including the application of PEEP can reduce postoperative pulmonary complications. In a prospective clinical observation study, we evaluated volume-dependent respiratory system compliance in adult patients undergoing ear-nose-throat surgery with ventilation settings chosen empirically by the attending anaesthetist. In 40 patients, we measured the respiratory variables during intraoperative mechanical ventilation. All measurements were subdivided into 5 min intervals. Dynamic compliance (CRS) and the intratidal volume-dependent CRS curve was calculated for each interval and classified into one of the six specific compliance profiles indicating intratidal recruitment/derecruitment, overdistension or all. We retrospectively compared the occurrences of the respective compliance profiles at PEEP levels of 5 cm H2O and at higher levels. The attending anaesthetists set the PEEP level initially to 5 cm H2O in 29 patients (83%), to 7 cm H2O in 5 patients (14%), and to 8 cm H2O in 2 patients (6%). Across all measurements the mean CRS was 61 (11) ml cm H2O(-1) (40-86 ml cm H2O(-1)) and decreased continuously during the procedure. At PEEP of 5 cm H2O the compliance profile indicating strong intratidal recruitment/derecruitment occurred more often (18.6%) compared with higher PEEP levels (5.5%, P<0.01). Overdistension was practically never observed. In most patients, a PEEP of 5 cm H2O during intraoperative mechanical ventilation is too low to prevent intratidal recruitment/derecruitment. The analysis of the intratidal compliance profile provides the rationale to individually titrate a PEEP level that stabilizes the alveolar recruitment status of the lung during intraoperative mechanical ventilation. DRKS00004286.

Impact of Extraperitoneal Dioxyde Carbon Insufflation on Respiratory Function in Anesthetized Adults: A Preliminary Study Using Electrical Impedance Tomography and Wash-out/Wash-in Technic.

Background:Extraperitoneal laparoscopy has become a common technique for many surgical procedures, especially for inguinal hernia surgery. Investigations of physiological changes occurring during extraperitoneal carbon dioxide (CO2) insufflation mostly focused on blood gas changes. To date, the impact of extraperitoneal CO2 insufflation on respiratory mechanics remains unknown, whereas changes in respiratory mechanics have been extensively studied in intraperitoneal insufflation.Objectives:The aim of this study was to investigate the effects of extraperitoneal CO2 insufflation on respiratory mechanics.Patients and Methods:A prospective and observational study was performed on nine patients undergoing laparoscopic inguinal hernia repair. Anesthetic management and intraoperative care were standardized. All patients were mechanically ventilated with a tidal volume of 8 mL/kg using an Engström Carestation ventilator (GE Healthcare). Ventilation distribution was assessed by electrical impedance tomography (EIT). End-expiratory lung volume (EELV) was measured by a nitrogen wash-out/wash-in method. Ventilation distribution, EELV, ventilator pressures and hemodynamic parameters were assessed before extraperitoneal insufflation, and during insufflation with a PEEP of 0 cmH2O, 5 cmH20 and of 10 cmH20.Results:EELV and thoracopulmonary compliance were significantly decreased after extraperitoneal insufflation. Ventilation distribution was significantly higher in ventral lung regions during general anesthesia and was not modified after insufflation. A 10 cmH20 PEEP application resulted in a significant increase in EELV, and a shift of ventilation toward the dorsal lung regions.Conclusions:Extraperitoneal insufflation decreased EELV and thoracopulmonary compliance. Application of a 10 cmH20 PEEP increased EELV and homogenized ventilation distribution. This preliminary clinical study showed that extraperitoneal insufflation worsened respiratory mechanics, which may justify further investigations to evaluate the clinical impact.

Efficacy and safety of open lung ventilation in patients with impaired peripheral chemoreflex sensitivity

Mechanical ventilation during anesthesia leads to the development of atelectasis, poor oxygenation and postoperative pulmonary complications. Application of PEEP and recruitment maneuver (RM) can significantly reduce the severity of atelectasis and improve lung function. But the application of this strategy often leads to hemodynamic instability, which may be associated with impaired reactivity of the cardiovascular system. The purpose of this study was to evaluate the efficacy and safety of RM in patients with increased sensitivity of peripheral chemoreceptors (SPCR), which reflects the decreasing reactivity of the cardiovascular system.

Ventilation strategies in acute asthma

Status asthmaticus is a condition of progressively worsening bronchospasm and respiratory dysfunction due to asthma, which is unresponsive to standard conventional therapy and may progress to respiratory failure. Despite initial aggressive management a small proportion of patients require ventilatory support. Ventilation in asthma is complex and presents a big challenge to the pediatric intensivist, with mortality rates in patients requiring ventilation approaching as high as 10%. It requires careful personalized management. NIV is increasingly being used and its early initiation has shown to improve outcome and avoid endotracheal intubation in some recent studies. During mechanical ventilation, our first goal is to maintain adequate gas exchange and the second goal is to minimize the risk of air trapping and auto PEEP. These goals are best achieved by adopting the strategy of controlled hypoventilation and permissive hypoxemia initially. Once recovery starts the patient is shifted to assisted or spontaneous mode. A cautious application of PEEP up to 80% of auto PEEP can be tried at this stage. Further recovery should prompt the intensivist to rapidly wean and extubate the patient. Intense pharmacotherapy must continue throughout ventilation. Caie should be taken to choose the most appropriate device for delivery of the aerosolized bronchodilators. Higher doses may be required to achieve the desired effect.

Postoperative atelectasis prevention by application of PEEP and pressure support ventilation

Postoperative atelectasis prevention by application of PEEP and pressure support ventilation

Impact of positive end-expiratory pressure application on ventriculo-arterial coupling in decompensated left ventricles after cardiac surgery: a non-invasive echocardiographic study

The management of ICU patients following heart surgery can be hustling when coping with severe left ventricular (LV) dysfunction. Single beat (Sb) measurements of ventriculo- arterial coupling (VAc) can be used by the intensivist when dealing with altered hemodynamic states [1]. LV elastance (Ees) and arterial elastance (Ea) can be measured by trasthoracic echocardiography (TTE) in a Sb fashion [2], so allowing quick assessment of VAc. PEEP application is common practice in the ICU but can have hemodynamic consequences and lead to instability. Speckle tracking analysis by TTE has been recently reported to help titrating PEEP in critically ill patients [3]. However, this can be demanding and require specific ultrasound tools. In this study we aimed to assess whether standard TTE can be useful in evaluating the effect of respiratory treatment with PEEP on cardiovascular efficiency by measuring VAc after coronary artery bypass surgery (CABG).

Opening pressures and intratidal opening and closing in ARDS lung

Intratidal opening/closing is believed to be one of the main triggers of ventilator-induced lung injury; the application of higher PEEP united with the limitation of plateau pressure at 30 cmH2O may limit this phenomenon. We aim to evaluate the intratidal opening/ closing at different PEEP levels and the amount of lung parenchyma that regains inflation going from 30 (pressure limit of tidal ventilation) to 45 cmH2O.

Acute cor pulmonale in ARDS

Acute cor pulmonale in ARDS

Recruitable volume is comparable in acute respiratory distress syndrome and in healthy lungs

The application of PEEP is commonly used in acute respiratory distress syndrome (ARDS) and has been shown to improve oxygenation. To identify patients that most benefit from the application of PEEP, the discrimination of recruiters and nonrecruiters has been postulated by Gattinoni and colleagues [1]. Recently, Dellamonica and colleagues [2] presented a method to predict alveolar recruitment. We hypothesised that the amount of recruitable volume allows the discrimination between ARDS patients and patients with healthy lungs (HL).

Individualized PEEP Setting in Subjects With ARDS: A Randomized Controlled Pilot Study

Low-tidal-volume ventilation may be associated with repetitive opening and closing of terminal airways. The use of PEEP is intended to keep the alveoli open. No method of adjusting the optimal PEEP has shown to be superior or to improve clinical outcomes. We conducted a pilot study to evaluate the effect of setting an individualized level of PEEP at the highest compliance on oxygenation, multiple-organ-dysfunction, and survival in subjects with ARDS. Subjects with ARDS ventilated with low tidal volumes and limitation of airway pressure to 30 cm H2O were randomized to either a compliance-guided PEEP group or an FIO2-guided group. Of the 159 patients with ARDS admitted during the study period, 70 met the inclusion criteria. Subjects in the compliance-guided group showed nonsignificant improvements in PaO2/FIO2 during the first 14 days, and in 28-day mortality (20.6% vs. 38.9%, P = .12). Multiple-organ-dysfunction-free days (median 6 vs 20.5 d, P = .02), respiratory-failure-free days (median 7.5 vs 14.5 d, P = .03), and hemodynamic-failure-free days (median 16 vs 22 d, P = .04) at 28 days were significantly lower in subjects with compliance-guided setting of PEEP. In ARDS subjects, protective mechanical ventilation with PEEP application according to the highest compliance was associated with less organ dysfunction and a strong nonsignificant trend toward lower mortality. ClinicalTrials.gov Number NCT01119872.

Goal-Directed Mechanical Ventilation: Are We Aiming at the Right Goals? A Proposal for an Alternative Approach Aiming at Optimal Lung Compliance, Guided by Esophageal Pressure in Acute Respiratory Failure

Patients with acute respiratory failure and decreased respiratory system compliance due to ARDS frequently present a formidable challenge. These patients are often subjected to high inspiratory pressure, and in severe cases in order to improve oxygenation and preserve life, we may need to resort to unconventional measures. The currently accepted ARDSNet guidelines are characterized by a generalized approach in which an algorithm for PEEP application and limited plateau pressure are applied to all mechanically ventilated patients. These guidelines do not make any distinction between patients, who may have different chest wall mechanics with diverse pathologies and different mechanical properties of their respiratory system. The ability of assessing pleural pressure by measuring esophageal pressure allows us to partition the respiratory system into its main components of lungs and chest wall. Thus, identifying the dominant factor affecting respiratory system may better direct and optimize mechanical ventilation. Instead of limiting inspiratory pressure by plateau pressure, PEEP and inspiratory pressure adjustment would be individualized specifically for each patient's lung compliance as indicated by transpulmonary pressure. The main goal of this approach is to specifically target transpulmonary pressure instead of plateau pressure, and therefore achieve the best lung compliance with the least transpulmonary pressure possible.

Does a Protective Ventilation Strategy Reduce the Risk of Pulmonary Complications After Lung Cancer Surgery?: A Randomized Controlled Trial

Protective ventilation strategy has been shown to reduce ventilator-induced lung injury in patients with ARDS. In this study, we questioned whether protective ventilatory settings would attenuate lung impairment during one-lung ventilation (OLV) compared with conventional ventilation in patients undergoing lung resection surgery. One hundred patients with American Society of Anesthesiology physical status 1 to 2 who were scheduled for an elective lobectomy were enrolled in the study. During OLV, two different ventilation strategies were compared. The conventional strategy (CV group, n=50) consisted of FIO2 1.0, tidal volume (Vt) 10 mL/kg, zero end-expiratory pressure, and volume-controlled ventilation, whereas the protective strategy (PV group, n=50) consisted of FIO2 0.5, Vt 6 mL/kg, positive end-expiratory pressure 5 cm H2O, and pressure-controlled ventilation. The composite primary end point included PaO2/FIO2<300 mm Hg and/or the presence of newly developed lung lesions (lung infiltration and atelectasis) within 72 h of the operation. To monitor safety during OLV, oxygen saturation by pulse oximeter (SpO2), PaCO2, and peak inspiratory pressure (PIP) were repeatedly measured. During OLV, although 58% of the PV group needed elevated FIO2 to maintain an SpO2>95%, PIP was significantly lower than in the CV group, whereas the mean PaCO2 values remained at 35 to 40 mm Hg in both groups. Importantly, in the PV group, the incidence of the primary end point of pulmonary dysfunction was significantly lower than in the CV group (incidence of PaO2/FIO2<300 mm Hg, lung infiltration, or atelectasis: 4% vs 22%, P<.05). Compared with the traditional large Vt and volume-controlled ventilation, the application of small Vt and PEEP through pressure-controlled ventilation was associated with a lower incidence of postoperative lung dysfunction and satisfactory gas exchange. Australian New Zealand Clinical Trials Registry; No.: ACTRN12609000861257; URL: www.anzctr.org.au.

Successfull High PEEP Application in a Pregnant Woman with ARDS Diagnosed with H1N1 Virus Infection

Successfull High PEEP Application in a Pregnant Woman with ARDS Diagnosed with H1N1 Virus Infection

Effect of low tidal volume ventilation on lung function and inflammation in mice

BackgroundA large number of studies have investigated the effects of high tidal volume ventilation in mouse models. In contrast data on very short term effects of low tidal volume ventilation are sparse. Therefore we investigated the functional and structural effects of low tidal volume ventilation in mice.Methods38 Male C57/Bl6 mice were ventilated with different tidal volumes (Vt 5, 7, and 10 ml/kg) without or with application of PEEP (2 cm H2O). Four spontaneously breathing animals served as controls. Oxygen saturation and pulse rate were monitored. Lung function was measured every 5 min for at least 30 min. Afterwards lungs were removed and histological sections were stained for measurement of infiltration with polymorphonuclear leukocytes (PMN). Moreover, mRNA expression of macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)α in the lungs was quantified using real time PCR.ResultsOxygen saturation did not change significantly over time of ventilation in all groups (P > 0.05). Pulse rate dropped in all groups without PEEP during mechanical ventilation. In contrast, in the groups with PEEP pulse rate increased over time. These effects were not statistically significant (P > 0.05). Tissue damping (G) and tissue elastance (H) were significantly increased in all groups after 30 min of ventilation (P < 0.05). Only the group with a Vt of 10 ml/kg and PEEP did not show a significant increase in H (P > 0.05). Mechanical ventilation significantly increased infiltration of the lungs with PMN (P < 0.05). Expression of MIP-2 was significantly induced by mechanical ventilation in all groups (P < 0.05). MIP-2 mRNA expression was lowest in the group with a Vt of 10 ml/kg + PEEP.ConclusionsOur data show that very short term mechanical ventilation with lower tidal volumes than 10 ml/kg did not reduce inflammation additionally. Formation of atelectasis and inadequate oxygenation with very low tidal volumes may be important factors. Application of PEEP attenuated inflammation.

Whole lung lavage: a unique model for ultrasound assessment of lung aeration changes

Whole lung lavage (WLL) pathophysiologically represents a human model of controlled lung de-aeration, resembling various pathological conditions encountered in the critically ill. Through one-lung ventilation and progressive alveolar flooding, it mimics, respectively, re-absorption atelectasis formation and lung consolidation. With re-ventilation of the treated lung, PEEP application and diuretics administration, it then creates a model of pulmonary edema and its progressive resolution. No studies have so far described lung aeration changes during WLL with ultrasound: objectives of the study were to describe ultrasound findings during WLL with validated semiotics in the critically ill and to investigate their relation with the lung's state of relative aeration. In seven patients, 12 lung areas/patient were prospectively studied with ultrasound during six procedural steps of WLL. A three-tiered pattern classification was assigned (1, normal/nearly normal; 2, alveolar-interstitial syndrome; 3, alveolar consolidation) consistently with their previously described meaning in terms of relative air content. The distribution was compared throughout different WLL maneuvers as it was for arterial oxygen measurement distribution. During one-lung ventilation and saline flooding, ultrasound findings shifted from artifact patterns (normal/nearly normal and alveolar-interstitial syndrome) to alveolar consolidation. Saline removal, re-ventilation and negative water balance were associated with a gradual return to alveolar-interstitial syndrome, then to a normal/nearly normal pattern. Arterial oxygen tension variations were not always consistent with these changes. In a controlled human model of lung air content variation, the different states of aeration determined by WLL procedure were reliably described with lung ultrasound.

Randomised controlled trial comparing application of PEEP and ZEEP during laparoscopic surgery by electrical impedance tomography (EIT)

Randomised controlled trial comparing application of PEEP and ZEEP during laparoscopic surgery by electrical impedance tomography (EIT)

Réglage du niveau de pression expiratoire positive au cours du syndrome de détresse respiratoire aiguë : un faux problème…

Whereas tidal volume reduction is now largely accepted as a prerequisite to protect the lungs in mechanically ventilated ARDS patients, a debate persists concerning the best PEEP to avoid excessive loss of functional residual capacity. This discussion should take into account the effect of PEEP application on pulmonary circulation, and not only on lung aeration, improvement in the latter usually being obtained at the expense of the former. An appropriate balance should thus be respected to obtain a functional, and not only anatomical, improvement.

Exhaled breath condensate mediators in mechanically ventilated brain-injured patients with no acute lung injury are mostly related to markers of systemic inflammation

Mechanical ventilation may induce lung injury in patients with normal lungs. Application of PEEP appears protective. Lung injury is associated with the production and release of inflammatory mediators. Such mediators have been identified in patients' exhaled breath condensate (EBC) in various lung pathologies. In this study we identified EBC inflammatory markers in 27 mechanically ventilated brain-injured subjects with neither acute lung injury (ALI) nor sepsis.

Response of acoustic transmission to positive airway pressure therapy in experimental lung injury

To evaluate the effect of positive end-expiratory pressure on the sound filtering characteristics of injured lungs. Prospective experimental study in the animal laboratory in an academic medical center. Six 35- to 45-kg anesthetized, intubated pigs. Acute lung injury with intravenous oleic acid. We injected a multifrequency broad-band sound signal into the airway while recording transmitted sound at three locations bilaterally on the chest wall. Oleic acid injections effected a severe pulmonary edema predominantly in the dependent lung regions, with an average increase in venous admixture from 16+/-14% to 57+/-13% and a reduction in static respiratory system compliance from 31+/-6 to 16+/-3 ml/cm H(2)O. A significant concomitant increase in sound transfer function amplitude was seen in the dependent and lateral lung regions; little change occurred in the nondependent areas. The application of PEEP resulted in a decrease in venous admixture, increase in respiratory system compliance, and return of the sound transmission to preinjury levels. Acute lung injury causes regional acoustic transmission abnormalities that are reversed during alveolar recruitment with PEEP.