Reply to: Respiratory acidosis in obese gynecologic patients undergoing laparoscopic surgery independently of the type of ventilation

Background There is controversy about whether capnography is adequate to monitor pulmonary ventilation to reduce the risk of significant respiratory acidosis in pregnant patients undergoing laparoscopic surgery. In this prospective study, changes in arterial to end-tidal carbon dioxide pressure difference (PaCO2--PetCO2), induced by carbon dioxide pneumoperitoneum, were determined in pregnant patients undergoing laparoscopic cholecystectomy. Methods Eight pregnant women underwent general anesthesia at 17-30 weeks of gestation. Carbon dioxide pnueumoperitoneum was initiated after obtaining arterial blood for gas analysis. Pulmonary ventilation was adjusted to maintain PetCO2 around 32 mmHg during the procedure. Arterial blood gas analysis was performed during insufflation, after the termination of insufflation, after extubation, and in the postoperative period. Results The mean +/- SD for PaCO2--PetCO2 was 2.4 +/- 1.5 before carbon dioxide pneumoperitoneum, 2.6 +/- 1.2 during, and 1.9 +/- 1.4 mmHg after termination of pneumoperitoneum. PaCO2 and pH during pneumoperitoneum were 35 +/- 1.7 mmHg and 7.41 +/- 0.02, respectively. There were no significant differences in either mean PaCO2--PetCO2 or PaCO2 and pH during various phases of laparoscopy. Conclusions Capnography is adequate to guide ventilation during laparoscopic surgery in pregnant patients. Respiratory acidosis did not occur when PetCO2 was maintained at 32 mmHg during carbon dioxide pneumoperitoneum.

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Inverse Ratio Ventilation for Preventing Intra-Operative Hypercapnia in Children Undergoing Laparoscopic Surgery

10.21203/rs.3.rs-154630/v1 ◽

2021 ◽

Author(s):

XD Han ◽

Wangping Zhang ◽

XH Qian

Keyword(s):

Laparoscopic Surgery ◽

Respiratory Acidosis ◽

Carbon Dioxide Tension ◽

Control Group ◽

Inverse Ratio Ventilation ◽

Group I ◽

Registration Number ◽

End Tidal ◽

Pressure Controlled ◽

Group 1

Abstract BackgroundHigh end-tidal carbon dioxide tension (PETCO2) and respiratory acidosis occurs frequently in patients undergoing laparoscopic surgery. The aim of this study is to be investigate the effect of pressure-controlled inverse ratio ventilation (IRV) with inspiratory to expiratory ratio (I: E) of 2:1 on children undergoing laparoscopic surgery. MethodsEighty children undergoing elective laparoscopic surgery were allocated randomly to the IRV group (1: E=2:1) and the control group (I: E=1:2). Children received pressure-controlled ventilation with I: E ratio of 2:1 or 1:2. Hemodynamic parameters and respiratory mechanics were recorded. Side effects were also recorded. ResultsAt 30 min after CO2 pneumoperitoneum, tidal volume (Vt) and arterial partial pressure of oxygen (PaO2) were greater in the IRV group than the control group (100.6 ± 6.6 vs. 95.1±7.9 ml, 282.7 ± 45.6 vs.246.5 ± 40.1mmHg, respectively) (P < 0.01), but PaCO2 was lower than the control group (43.9 ± 5.45 vs. 46.7 ± 4.90 mmHg, P = 0.013). The incidence of intra-operative hypercapnia was lower in the IRV group (25% vs. 42.5%, P= 0.03). ConclusionIRV may reduce the incidence of intra-operative hypercapnia as well as increasing Vt and thus improving CO2 elimination in children undergoing laparoscopy. (Registration number: ChiCTR2000035589)

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