Effects of Different Inhalation Oxygen Concentrations on Postoperative Atelectasis

China Medical University, China96 enrolled

Overview

This study was a single-center, prospective, randomized controlled, two-arm study. This study will be conducted in the First Hospital of China Medical University. the investigators aimed to investigate the effects of different inspired oxygen concentrations in lung protective ventilation strategies on immediate postoperative atelectasis and intraoperative changes of oxygenation index in patients undergoing neurosurgical surgery in the supine position. A total of 96 neurosurgical patients under supine position were selected with an estimated operation time of more than 2 hours. Patients were randomly assigned to low-oxygen concentration (30%FiO2) L group, or high-oxygen concentration (60%FiO2) H group, and both groups received lung protective ventilation strategies. The main outcome was the comparison of postoperative atelectasis volume between the two groups. Secondary outcomes were the comparison of intraoperative oxygenation index and postoperative changes in diaphragm height between the two groups.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Enrollment

Conditions

Atelectasis

Interventions

30% OxygenDRUG

Before anesthesia induction, the participants inhaled pure oxygen through the mask for 5 mins. After successful anesthesia induction, Fio2 will be adjusted to 30%, and the total gas flow rate will be set at 2L/min. All patients will be performed via the lung protective ventilation strategy. The respiratory parameters are VT: 6-8ml/kg, PEEP: 6-8 cmh2O, RR: 1:2, and respiratory rate will be adjusted by maintaining a partial pressure of carbon dioxide at 35-45 mmHg. Manual lung recruitment maneuvers will be performed after tracheal intubation and before tracheal extubation, however when intraoperative oxygen saturation is less than 92% the manual lung recruitment maneuver will be done too. Arterial blood will be collected twice for blood gas analysis, the first once is in the non-oxygen inhalation state before anesthesia induction and the second is 30min before the end of surgery. Patients in both groups will be extubated in the operating room and then sent to the PACU.

60% OxygenDRUG

Before anesthesia induction, the participants inhaled pure oxygen through the mask for 5 mins. After successful anesthesia induction, Fio2 will be adjusted to 60%, and the total gas flow rate will be set at 2L/min. All patients will be performed via the lung protective ventilation strategy. The respiratory parameters are VT: 6-8ml/kg, PEEP: 6-8 cmh2O, RR: 1:2, and respiratory rate will be adjusted by maintaining a partial pressure of carbon dioxide at 35-45 mmHg. Arterial blood will be collected twice for blood gas analysis, the first once is in the non-oxygen inhalation state before anesthesia induction and the second is 30min before the end of surgery. Patients in both groups will be extubated in the operating room and then sent to the PACU.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * patients with American Society of Anesthesiologist (ASA) physical status I-II; * Older than 18 years; Patients with operation time more than 2 hours and plan to extubate in the operating room; * Preoperative blood gas partial pressure of oxygen was more than 80mmHg; * Patients scheduled for elective neurosurgery were operated in the supine position. Exclusion Criteria: * A history of acute lung injury with acute respiratory distress syndrome within three months; * Heart failure (New York Heart Association class) greater than IV, severe liver and kidney dysfunction (Child B or C liver failure, glomerular filtration rate \<30ml/min); * BMI \> 30 kg/m2. * The operation time is more than 10 hours; * The amount of bleeding was more than 500ml; The total fluid volume exceeded 3000ml.

Locations (1)

the First Hospital of China Medical University

Shenyang, Liaoning, China

Outcomes

Primary Outcomes

the occurrence of atelectasis

The primary outcome is the occurrence of atelectasis scanned by computerized tomography in the operating room within 40 minutes after awakening.

Time frame: On the operating room within 40 minutes after awakening

Secondary Outcomes

oxygenation index

The secondary outcome is the comparison of the oxygenation index between the two groups, which is calculated and compared from the results of intraoperative blood gas analysis.

Time frame: On the operating room within 40 minutes after awakening

bilateral diaphragmatic muscles

By comparing the preoperative and postoperative lung CT, the distance between the two lungs to the bilateral diaphragmatic muscles will be calculated and compared.

Time frame: On the operating room within 40 minutes after awakening

Data from ClinicalTrials.gov

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