The goal of this clinical trial is to compare three open-lung strategies on respiratory function and lung injury in protective ventilation for laparoscopic anterior resection. It aims to answer whether a periodic alveolar recruitment maneuvers (PARM) strategy alone was an appropriate open-lung strategy in intraoperative protective ventilation. Patients were randomly assigned (1:1:1) to receive one of three open-lung strategies in protective ventilation: PARM alone (alveolar recruitment maneuvers \[ARM\] repeated every 30 min), positive end-expiratory pressure (PEEP) alone (a PEEP of 6 to 8 cm H2O), or a combination of PEEP and PARM (a PEEP of 6 to 8 cm H2O combined with ARM repeated every 30 min). The primary outcome is the mechanical power before the end of intraoperative mechanical ventilation. Secondary outcomes included the accumulative intraoperative mechanical power, an arterial partial pressure of oxygen (PaO2) / inhaled oxygen concentration (FiO2) ratio (P/F ratio) before the end of intraoperative mechanical ventilation, the rates of respiratory failure at post-anesthesia care unit (PACU) and three postoperative days, the concentration of soluble advanced glycation end products receptor (sRAGE) and Clara cell protein 16 (CC16) at the end of surgery, postoperative pulmonary complications score, postoperative hospitalization days and so on.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
75
A stepwise increment of tidal volume was used for each ARM.
a PEEP of 6 to 8 cm H2O
The Sixth Affiliated Hospital, Sun Yat-sen University
Guangzhou, Guangdong, China
Intraoperative mechanical power
Intraoperative mechanical power, calculated from values of tidal volume (Vt ), respiratory rate (RR), positive end-expiratory pressure (PEEP), plateau pressure (Pplat), and peak inspiratory pressure (Ppeak), using the following formula: mechanical power (J/min) = 0.098 × RR × Vt × (PEEP + ½\[Pplat - PEEP\] + \[Ppeak - Pplat\])
Time frame: Before the end of intraoperative mechanical ventilation, about 5 to 10 minutes before the end of surgery
Mechanical power during capnoperitoneum
mechanical power, J/min
Time frame: 30 minutes after starting carbon dioxide pneumoperitoneum
Accumulative mechanical power (AMP)
Accumulative mechanical power (AMP) = AMP before capnoperitoneum + AMP during capnoperitoneum + AMP after capnoperitoneum. Accumulative mechanical power before capnoperitoneum = mechanical power before capnoperitoneum (10 min after mechanical ventilation) × the length of mechanical ventilation before capnoperitoneum. Accumulative mechanical power during capnoperitoneum = mechanical power during capnoperitoneum (30 min after mechanical ventilation) × the length of mechanical ventilation during capnoperitoneum. Accumulative mechanical power after capnoperitoneum (after the end of capnoperitoneum) = mechanical power after capnoperitoneum (10 min after the end of capnoperitoneum) × the length of mechanical ventilation after capnoperitoneum
Time frame: During intraoperative mechanical ventilation, an average of 3 hours
An arterial partial pressure of oxygen (PaO2) / Inhaled oxygen concentration (FIO2) ratio (P/F ratio)
P/F ratio, mmHg
Time frame: Before the end of intraoperative mechanical ventilation, about 5 to 10 minutes before the end of surgery
Shunt fraction
Shunt fraction, %
Time frame: Before the end of intraoperative mechanical ventilation, about 5 to 10 minutes before the end of surgery
Dead space rate
Arterial carbon dioxide partial pressure (PaCO2); partial pressure of carbon dioxide in end expiratory gas (PetCO2); Dead space fraction = (PaCO2-PetCO2)/ PaCO2.
Time frame: Before the end of intraoperative mechanical ventilation, about 5 to 10 minutes before the end of surgery
Rate of respiratory failure at post-anesthesia care unit (PACU)
Respiratory failure: PaO2 \< 60 mmHg or pulse oxygen saturation (SpO2) \< 90% on room air, or a P/F ratio \< 300 mmHg and requiring oxygen therapy.
Time frame: Stay in the PACU for at least 20 minutes and at most 3 hours; assessed at 5 to 10 minutes before leaving PACU
Soluble advanced glycation end products receptor (sRAGE)
The concentration of plasma sRAGE, pg/ml
Time frame: 20 minutes after entering PACU
Clara cell protein 16 (CC16)
The concentration of plasma CC16, ng/ml
Time frame: 20 minutes after entering PACU
Surfactant Protein D (SP-D)
The concentration of plasma SP-D, ug/ml
Time frame: 20 minutes after entering PACU
Interleukin 6 (IL-6)
The concentration of plasma IL-6, pg/ml
Time frame: 20 minutes after entering PACU
Rate of postoperative respiratory failure
Respiratory failure: PaO2 \< 60 mmHg or SpO2 \< 90% on room air, or a P/F ratio \< 300 mmHg and requiring oxygen therapy.
Time frame: Time Frame: Day 0 to 3 after surgery
Rate of sustained hypoxaemia
Sustained hypoxaemia, hypoxaemia at any two consecutive days; hypoxaemia: during a follow-up visit when the patient was awake and breathing room air, SpO2 ≤ 92% or the change of SpO2 (ΔSpO2, preoperative SpO2 minus postoperative SpO2) ≥ 5%.
Time frame: Day 0 to 3 after surgery
Postoperative pulmonary complications score
Postoperative pulmonary complications score: Operational Definitions of Postoperative Pulmonary Complications (Doi: 10.1001/jama.296.15.1851), graded on a scale from 0 (no pulmonary complications) to 4 (the most severe complications).
Time frame: Day 0 to 3 after surgery
Postoperative hospitalization days
The duration between the operation date and the actual discharge date.
Time frame: Day 0 to 30 after surgery
Death from any cause
Intraoperative or postoperative death from any cause
Time frame: Day 0 to 30 after surgery
Rate of intraoperative hypotension
Intraoperative hypotension, mean arterial pressure (MAP) \< 60 mmHg lasting more than 3 minutes.
Time frame: During intraoperative mechanical ventilation, an average of 3 hours
Rate of need for vasoconstrictors
MAP \< 60 mmHg and using any vasoconstrictors.
Time frame: During intraoperative mechanical ventilation, an average of 3 hours
Rate of intraoperative hypoxemia
Intraoperative hypoxemia, SpO2 ≤ 92% lasting more than 3 minutes.
Time frame: During intraoperative mechanical ventilation, an average of 3 hours
Rate of intraoperative bradycardia
Intraoperative bradycardia, heart rate ≤ 50 bpm and the decrease of heart rate from the basic value ≥ 20% lasting more than 3 minutes.
Time frame: During intraoperative mechanical ventilation, an average of 3 hours
Rate of pneumothorax
Pneumothorax, air in the pleural space with no vascular bed surrounding the visceral pleura.
Time frame: During surgery or within 7 days after surgery
Rate of pleural effusion
Pleural effusion, diagnosed according to previous literature (Doi: 10.1097/EJA.0000000000000118).
Time frame: within 7 days after surgery
Unexpected admission to ICU
It does not include the patients who enter ICU at the request of surgeons but have normal spontaneous breathing, stable circulation and no disturbance of consciousness.
Time frame: within 30 days after surgery
Tumor Necrosis Factor alpha (TNF-α)
TNF-α, pg/ml.
Time frame: 20 minutes after entering PACU
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