Driving Pressure in Neurosurgery (DPNS)

Driving Pressure for Early Postoperative Redistribution of Pulmonary Ventilation in Neurosurgery : A Prospective Randomized Controlled Trial

The effect of driving pressure (DP)-guided positive end expiratory pressure (PEEP) on early postoperative pulmonary ventilation is to be determined for patients undergoing neurosurgery. Patients are recruited to receive volume controlled ventilation with either a fixed PEEP (5cmH2O) or DP titrated PEEP. Early postoperative regional distribution of lung ventilation, expressed as global inhomogeneity (GI) is evaluated by electrical impedance tomography (EIT), a noninvasive, radiation free modality. Center of ventilation (COV) by EIT, as well as the lung ultrasonography（LUS), perioperative ventilatory parameters, arterial oxygenation index (PaO2/FiO2) , serum indicators and postoperative pulmonary complications are secondary outcome variables.

Study Overview

• Status: Completed
• Conditions: Neurosurgery
• Intervention / Treatment: Procedure: PEEP

Detailed Description

After screened for preoperative risk factors, 44 patients undergoing elective neurosurgery and planned to be extubated in the operating room are randomly assigned to two groups: (1) PEEP = 5cmH2O; (2) driving pressure (DP)-guided PEEP. The ventilation protocol consists of volume-controlled mechanical ventilation (Datex Ohmeda S/5 Advance; General Electric Company Healthcare, Helsinki, Finland) at a tidal volume (VT) of 8 ml/kg predicted body weight (PBW), fresh gas of 2 litre /min, inspiratory to expiratory ratio of 1:2, and a respiratory rate adjusted to normocapnia (arterial carbon dioxide partial pressure between 35 and 45 mmHg). For group 2, trial for the lowest DP was started 10 min after position adjustment by increasing PEEP from 2 to 10 cm H2O incrementally. DP was calculated as "plateau pressure - PEEP". Each PEEP level was maintained for 10 respiratory cycles, with DP in the last cycle recorded. Then the PEEP level producing the lowest DP was identified and maintained intraoperatively. A plateau pressure of no more than 30 cmH2O is targeted in each group. Early postoperative distribution of regional ventilation global inhomogeneity (GI) is the primary endpoint evaluated by EIT (electrical impedance tomography), which was performed by a trained technician who is blinded to randomization. Center of ventilation (COV) by EIT, lung ultrasonography（LUS) , and arterial blood gas are evaluated, with inflammatory and oxidative mediators tested from venous sample. Brain relaxation will be scored by the neurosurgeon. Postoperative pulmonary complications within 3 days are also recorded.

• Study Type: Interventional
• Enrollment (Actual): 55
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Beijing
    • Beijing, Beijing, China, 100070
      • Department of Anesthesiology,Beijing Tiantan Hospital, Capital Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Informed consent has been obtained
• Elective neurosurgery
• Expected ventilation duration > 2 hours
• Scheduled to be extubated in the operation
• American Society of Anesthesiologists (ASA) physical status >2

Exclusion Criteria:

• Mechanical ventilation of > 1 hour within the last 2 weeks before surgery
• Dysphagia resulting from preoperative cranial nerve damage
• Body mass index ≥ 35 kg/m2
• Acute respiratory failure (pneumonia, acute lung injury or acute respiratory distress syndrome)
• Emergency surgery
• Severe cardiac disease
• Progressive neuromuscular illness
• Pregnancy
• Refusal to participate
• Contradicted to EIT scan or lung ultrasound scan

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Conventional PEEP; PEEP = 5 cmH2O	Procedure: PEEP; Driving pressure (DP) is calculated as "plateau pressure - PEEP". 10min after position adjustment, PEEP is increased from 2 to 10 cm H2O incrementally. Each PEEP level is maintained for 10 respiratory cycles, with DP in the last cycle recorded. Then the PEEP level producing the lowest DP will be identified and maintained intraoperatively.
Experimental: Driving pressure (DP) guided-PEEP; PEEP is increased from 2 to 10 cm H2O incrementally. Each PEEP level is maintained for 10 respiratory cycles, with DP in the last cycle recorded. Then the PEEP level producing the lowest DP will be identified and maintained intraoperatively.	Procedure: PEEP; Driving pressure (DP) is calculated as "plateau pressure - PEEP". 10min after position adjustment, PEEP is increased from 2 to 10 cm H2O incrementally. Each PEEP level is maintained for 10 respiratory cycles, with DP in the last cycle recorded. Then the PEEP level producing the lowest DP will be identified and maintained intraoperatively.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
early postoperative overall spatial distribution of pulmonary ventilation	global inhomogeneity index (GI): overall degree of spatial heterogeneity of ventilation. GI is measured by electrical impedance tomography (EIT). A smaller GI index represents a more homogeneous distribution, and a larger GI index indicates a more inhomogeneous ventilation.	immediately after extubation

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Melbourne Group Scale version 2 (MGS-2)	Melbourne Group Scale version 2 (MGS-2): Temperature >38°C; White cell count >11.2 or use of respiratory antibiotics; Physician diagnosis of pneumonia or chest infection; Chest X-ray findings of atelectasis/consolidation; Production of purulent (yellow/green) sputum different from preoperative sputum; Positive results upon sputum microbiological analysis; oxygen saturation by pulse oximetry (SpO2)<90% in ambient air; Re-admission to or prolonged stay (>36 h) in the intensive care unit/high dependency unit for respiratory problems. A postoperative pulmonary complication (PPC) was diagnosed if 4 or more of the 8 factors were present.	within the first 3 days after surgery

Collaborators and Investigators

• Sponsor: Capital Medical University
• Investigators: Study Director: Ruquan Han, MD,PHD, Beijing Tiantan Hospital affiliated with Capital Medical University

Study record dates

Study Major Dates

• Study Start (Actual): June 21, 2020
• Primary Completion (Actual): April 1, 2021
• Study Completion (Actual): July 1, 2021

Study Registration Dates

• First Submitted: May 29, 2020
• First Submitted That Met QC Criteria: June 4, 2020
• First Posted (Actual): June 9, 2020

Study Record Updates

• Last Update Posted (Actual): July 6, 2021
• Last Update Submitted That Met QC Criteria: July 1, 2021
• Last Verified: July 1, 2021

More Information

Terms related to this study

• Other Study ID Numbers: DP-Neurosurgery

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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