Noninvasive carbon dioxide monitoring in pediatric patients undergoing laparoscopic surgery: transcutaneous vs. end-tidal techniques

Abstract

Purpose The present study aimed to investigate the correlation between transcutaneous carbon dioxide partial pressure (PtcCO2) and arterial carbon dioxide pressure (PaCO2) and the accuracy of PtcCO2 in predicting PaCO2 during laparoscopic surgery in pediatric patients. Methods Children aged 2–8 years with American Society of Anesthesiologists (ASA) class I or II who underwent laparoscopic surgery under general anesthesia were selected. After anesthesia induction and tracheal intubation, PtcCO2 was monitored, and radial arterial catheterization was performed for continuous pressure measurement. PaCO2, PtcCO2, and end-tidal carbon dioxide partial pressure (PetCO2) were measured before pneumoperitoneum, and 30, 60, and 90 min after pneumoperitoneum, respectively. The correlation and agreement between PtcCO2 and PaCO2, PetCO2, and PaCO2 were evaluated. Results A total of 32 patients were eventually enrolled in this study, resulting in 128 datasets. The linear regression equations were: PtcCO2 = 7.89 + 0.82 × PaCO2 (r2 = 0.70, P < 0.01); PetCO2 = 9.87 + 0.64 × PaCO2 (r2 = 0.69, P < 0.01). The 95% limits of agreement (LOA) of PtcCO2 – PaCO2 average was 0.66 ± 4.92 mmHg, and the 95% LOA of PetCO2 – PaCO2 average was –4.4 ± 4.86 mmHg. A difference of ≤ 5 mmHg was noted between PtcCO2 and PaCO2 in 122/128 samples and between PetCO2 and PaCO2 in 81/128 samples (P < 0.01). Conclusion In pediatric laparoscopic surgery, a close correlation was established between PtcCO2 and PaCO2. Compared to PetCO2, PtcCO2 can estimate PaCO2 accurately and could be used as an auxiliary monitoring indicator to optimize anesthesia management for laparoscopic surgery in children; however, it is not a substitute for PetCO2. Registration number of Chinese Clinical Trial Registry ChiCTR2100043636.

Recent Technologies for Transcutaneous Oxygen and Carbon Dioxide Monitoring

“…Nevertheless, in certain scenarios, this transcutaneous assessment can yield valuable insights that extend beyond the information provided by arterial partial pressures. In fact, the transcutaneous pressure derives both from the blood and from cells' metabolism [14], which depends on an adequate supply of O 2 and an appropriate amount of CO 2 to maintain an acid-base balance [15]. Thus, transcutaneous sensing can give information either on abnormal ventilation [1] or the perfusion of tissues.…”

“…Typically, heating the skin to a range between 37 • C and 45 • C makes the skin blood flow increase by three to four times, enhancing the arterial blood contribution by opening the precapillary sphincter arterioles, a phenomenon known as arterialization [17]. As a consequence, the diffusion of blood gases and the delivery of blood beneath the sensor increase [14,17,26] by the means permeability improvements in the arterioles and capillaries [14,17]. Furthermore, local warming is used to normalize the blood flow and is a strategic approach to standardizing the conditions around the monitoring site, allowing for more reliable and consistent transcutaneous measurements.…”

“…It must be noted that increasing the skin temperature also determines an increase in the metabolism of the cells. Consequently, there is an excess of CO 2 [14,28] and an increased consumption of O 2 . An increase in PCO 2 by 4.5%/ • C [8] induces tissue hypercarbia [17], so the interpretation of the measured value must consider the operating conditions in terms of heating [17] through the application of a correction factor [8].…”

“…Skin warming has an important role in transcutaneous measurements also because it improves the correlation between arterial partial pressure and transcutaneous partial pressure [14,17,31], increases sensitivity to low levels of oxygen [7], and stabilizes noise fluctuations [32]. Accordingly, the temperatures that are found in the literature are 40-42 • C for PtCO 2 [10,26,32,33], with 44 • C as the threshold not to be exceeded [34], and 43-44 • C for PtO 2 [10], with 45 • C being the maximum tolerable temperature [35].…”

“…Even if it is a consolidated technique, its accuracy is compromised both in intubated [14,39] and non-intubated patients [1,8], and many studies suggest that PtCO 2 is preferred over PetCO 2 [8], with the former being more accurate [14,51]. In addition, certain situations may affect the reliability of this measurement.…”