Abstract
BACKGROUND: To analyze the effects of pressure-controlled volume-guaranteed ventilation (PCV-VG) and volume-controlled ventilation (VCV) on postoperative pulmonary complications (PPCs) after oral and maxillofacial surgery with free flap reconstruction. METHODS: This was a prospective, randomized, controlled trial comparing two intraoperative ventilation strategies. Two hundred and forty patients who underwent oral and maxillofacial surgery with free flap reconstruction were randomly allocated to either VCV group (n = 120) or the PCV-VG group (n = 120). After induction of anesthesia, for both modes of ventilation, the target tidal volume (VT) was 6 mL/kg and the respiratory rate was adjusted to avoid hypercarbia. The primary outcome was a composite of postoperative pulmonary complications within the first seven postoperative days. The peak and mean inspiratory pressures and dynamic compliance were recorded at T1(the time after the patients entered the operation room), T2 (the time of skin incision), T3 (the time when anastomosing blood vessels), T4 (the time of closure of the incision). And oxygenation index (OI) and arterial partial pressure of oxygen (PaO(2)) / fraction of inspiration oxygen (FiO(2)) were calculated and recorded at T1 and T4. RESULTS: The two groups had similar characteristics at baseline. 26.7% patients in PCV-VG group, and 34.2% patients in VCV group experienced PPCs within the first 7 days after surgery (P = 0.051). In the first 7 days after surgery, the PCV-VG group had a better postoperative survival probability, but without significant statistical differences (Log-rank test, P = 0.056). But in tracheotomy patients, PCV-VG group had a lower incidence of PPCs (P < 0.05). In addition, the PCV-VG group had a shorter length of stay in hospital after surgery (9 days vs. 10 days, P = 0.041). Furthermore, PCV-VG group had significantly lower peak inspiratory pressure and greater dynamic compliance than VCV group (P < 0.05). At the same time, OI and PaO(2)/FiO(2) were better in PCV-VG group (P < 0.05). CONCLUSIONS: For patients undergoing oral and maxillofacial surgery with free flap reconstruction who were at intermediate or high risk of developing PPCs, PCV-VG could shorten the length of stay in hospital and showed a trend toward being superior to VCV in its ability to provide ventilation with lower peak inspiratory pressure, greater dynamic compliance, and better oxygenation. Meanwhile, in tracheotomy patients, the PCV-VG group had a lower incidence of PPCs. TRIAL REGISTRATION: Chinese Clinical Trial Registry, www.chictr.org.cn , number: ChiCTR2200060865; Registered on June 12, 2022.