Effects of PEEP on Parameters of Tissue Perfusion in Patients Post Cardiac Surgery

Effects of PEEP on Parameters of Tissue Perfusion and Clinical Outcomes After Coronary Artery Bypass Graft Surgery - a Randomized Clinical Trial

Pulmonary dysfunction is a condition inherent in cardiac surgery because of various interventions, such as general anesthesia, a median sternotomy, cardiopulmonary bypass and establishment of internal thoracic artery dissection.

In situations when there is a deterioration in oxygenation, increased positive pressure on the airways end pressure (PEEP) can be used as therapeutic mode by reversing severe hypoxemia resulting pulmonary shunt. But the use of PEEP has been associated to reduced cardiac output, due mainly to decrease systemic venous return consequent to increased intrathoracic pressure, and thus might reduce tissue oxygenation. Moreover, the increased transpulmonary gradient may also impair right ventricular ejection exacerbating the hemodynamic consequences in some patients, which in clinical practice this diagnosis may be difficult to perform.

In hypovolemic patients or those with cardiac changes may become even more pronounced, resulting in accentuation of low flow and systemic hypotension entailing changes in markers of tissue perfusion commonly measured by venous saturation central difference venoarterial carbon dioxide and lactate. The hypothesis of the investigators is that PEEP of 10 cmH2O and 15 cmH2O can be applied to reverse lung damage in patients in the immediate postoperative myocardial revascularization without repercussion tissue importantly in markers of tissue perfusion.

The objective is to evaluate the effects of different optimization levels of PEEP on gas exchange and influences the tissue perfusion after coronary artery bypass graft surgery.

Study Overview

• Status: Unknown
• Conditions: Coronary Artery Disease; Acute Lung Injury; Coronary Artery Bypass Grafting
• Intervention / Treatment: Other: Group G5; Other: Group G10; Other: Group G15

Detailed Description

This is a prospective, randomized study and will be performed on patients who accept coronary artery bypass grafting with cardiopulmonary bypass, the conscious openness to participate in the study. Age, sex, body mass index (BMI), smoking habits, diagnosis, additional diseases, drugs used, surgery, intervention, peroperative supportive treatments, left ventricular ejection fraction, post operative blood and cardiopulmonary bypass (CPB) time (min), cross clamp time (min), duration of operation, postoperative extubation period, intensive care day of hospitalization, day of hospitalization will be recorded.The study was planned in 3 groups. Group G5 (control group: no changes will be made to the value of PEEP). Group G10 [after 30 minutes of admission (time 0) the PEEP will be raised to 10 cmH2O (time1) for 30 minutes and then returned to 5 cmH2O (time 2)]. Group G15 [after 30 minutes of admission (time 0) the PEEP will be raised to 15 cmH2O (time 1) for 30 minutes and then returned to 5 cm H2O (time 2)]. At each time of protocol (0, 1 and 2) will be collected: arterial blood gas measurements (partial pressure of arterial oxygen [PaO2] and partial pressure of carbon dioxide ([PaCO2]), the ratio between the partial oxygen pressure, inspired oxygen fraction (PaO2/FiO2) and pH. Also, will be performed parameters of tissue perfusion: central venous oxygen saturation ([SVO2]), arterial blood lactate, venoarterial CO2 difference ([Dif VA CO2]) and vital signs. In all other respects, treatment will follow the standard of care.

• Study Type: Interventional
• Enrollment (Actual): 125
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• elective and isolated CABG, ejection fraction greater than 40%

Exclusion Criteria:

• patients with a diagnosis of pulmonary disease, emergency surgery and mechanical ventilation prior to surgery.

Postoperative patients who had radiological abnormalities suggestive of pneumothorax, atrial or ventricular arrhythmias, electrical ischemic changes on ECG, pulse pressure variation of more than 13, hemodynamic instability characterized by mean arterial pressure less than 60 mmHg, nor epinephrine greater than 0.5 mcg/Kg/ min and the presence of increased bleeding through the drains (greater than 2 ml \ kg \ h) the protocol was discontinued and the patient excluded from the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: RANDOMIZED
• Interventional Model: SEQUENTIAL
• Masking: TRIPLE

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
SHAM_COMPARATOR: Group G5; Patients submitted to CABG and peep 5	Other: Group G5; Submitted to peep 5
EXPERIMENTAL: Group G10; Patients submitted to CABG and peep 10	Other: Group G10; Submitted to peep 10
EXPERIMENTAL: Group G15; Patients submitted to CABG and peep 15	Other: Group G15; Submitted to peep 15

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pulmonary events	Pleural effusion was considered relevant when exceeding the phrenicocostal angle and fluid drainage was monitored hourly. Atelectasis was acknowledged when a clear atelectasis radiologic shadow exceeded 15 mm in width, with linear atelectasis	Through study completion, an average of 24 hours after surgery
Arterial oxygenation	arterial blood gas measurements (partial pressure of arterial oxygen [PaO2]	Immediately after arrival at the intensive care unit until the end of protocol (around 5 hours)
Tissue oxygenation	(central venous oxygen saturation , arterial blood lactate and venoarterial CO2 difference	Immediately after arrival at the intensive care unit until the end of protocol (around 5 hours)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Length of intensive care unit (ICU) stay	Days since surgery until ICU discharge	From the day of surgery up to ICU discharge, maximum censoring at day 28 after surgery ]
Length of Hospital Stay	Days since surgery until Hospital discharge	From the day of surgery up to Hospital discharge, maximum censoring at day 28 after surgery ]
Duration of mechanical ventilation	Hours since surgery until extubation	Through study completion, an average of 24 hours after surgery

Collaborators and Investigators

• Sponsor: Federal University of São Paulo
• Collaborators: Vanessa Marques Ferreira

Study record dates

Study Major Dates

• Study Start (ACTUAL): January 1, 2012
• Primary Completion (ANTICIPATED): December 1, 2019
• Study Completion (ANTICIPATED): December 1, 2019

Study Registration Dates

• First Submitted: November 21, 2018
• First Submitted That Met QC Criteria: November 21, 2018
• First Posted (ACTUAL): November 26, 2018

Study Record Updates

• Last Update Posted (ACTUAL): November 29, 2018
• Last Update Submitted That Met QC Criteria: November 27, 2018
• Last Verified: November 1, 2018

More Information

Terms related to this study

• Keywords: Acute Lung Injury; postoperative of cardiac surgery
• Additional Relevant MeSH Terms: Myocardial Ischemia; Heart Diseases; Cardiovascular Diseases; Vascular Diseases; Respiratory Tract Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Lung Diseases; Wounds and Injuries; Coronary Disease; Thoracic Injuries; Coronary Artery Disease; Acute Lung Injury; Lung Injury
• Other Study ID Numbers: 89704818.6.0000.5505

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No