Transcutaneous PCO2 monitoring during laparoscopic cholecystectomy in pregnancy

Nocturnal Hypoventilation in the Patients Submitted to Thoracic Surgery

Introduction

Nocturnal hypoventilation may occur due to obesity, concomitant chronic obstructive pulmonary disease (COPD), obstructive sleep apnea, and/or the use of narcotic analgesics. The aim of the study was to evaluate the risk and severity of nocturnal hypoventilation as assessed by transcutaneous continuous capnography in the patients submitted to thoracic surgery.

Materials and Methods

The material of the study consisted of 45 obese (BMI 34.8 ± 3.7 kg/m2) and 23 nonobese (25.5 ± 3.6 kg/m2) patients, who underwent thoracic surgery because of malignant (57 patients) and nonmalignant tumors. All the patients received routine analgesic treatment after surgery including intravenous morphine sulfate. Overnight transcutaneous measurements of CO2 partial pressure (tcpCO2) were performed before and after surgery in search of nocturnal hypoventilation, i.e., the periods lasting at least 10 minutes with tcpCO2 above 55 mmHg.

Results

Nocturnal hypoventilation during the first night after thoracic surgery was detected in 10 patients (15%), all obese, three of them with COPD, four with high suspicion of moderate-to-severe OSA syndrome, and one with chronic daytime hypercapnia. In the patients with nocturnal hypoventilation, the mean tcpCO2 was 53.4 ± 6.1 mmHg, maximal tcpCO2 was 59.9 ± 8.4 mmHg, and minimal tcpCO2 was 46.4 ± 6.7 mmHg during the first night after surgery. In these patients, there were higher values of minimal, mean, and maximal tcpCO2 in the preoperative period. Nocturnal hypoventilation in the postoperative period did not influence the duration of hospitalization. Among 12 patients with primary lung cancer who died during the first two years of observation, there were 11 patients without nocturnal hypoventilation in the early postoperative period.

Conclusion

Nocturnal hypoventilation may occur in the patients after thoracic surgery, especially in obese patients with bronchial obstruction, obstructive sleep apnea, or chronic daytime hypercapnia, and does not influence the duration of hospitalization.

Respiratory Monitoring: Current State of the Art and Future Roads

In this article, we present current methodologies, available technologies, and demands for monitoring various respiratory parameters. We discuss the importance of noninvasive techniques for remote and continuous monitoring and challenges involved in the current "smart and connected health" era. We conducted an extensive literature review on the medical significance of monitoring respiratory vital parameters, along with the current methods and solutions with their respective advantages and disadvantages. We discuss the challenges of developing a noninvasive, wearable, wireless system that continuously monitors respiration parameters and opportunities in the field and then determines the requirements of a state-of-the-art system. Noninvasive techniques provide a significant amount of medical information for a continuous patient monitoring system. Contact methods offer more advantages than non-contact methods; however, reducing the size and power of contact methods is critical for enabling a wearable, wireless medical monitoring system. Continuous and accurate remote monitoring, along with other physiological data, can help caregivers improve the quality of care and allow patients greater freedom outside the hospital. Such monitoring systems could lead to highly tailored treatment plans, shorten patient stays at medical facilities, and reduce the cost of treatment.

Transcutaneous partial pressure of carbon dioxide monitoring during EUS-guided drainage of peripancreatic fluid collections using carbon dioxide insufflation: A prospective study

Background:

Carbon dioxide (CO₂) insufflation has become more commonly used in EUS-guided interventions in recent years. However, there is a paucity of information regarding methods by which to monitor in vivo CO₂ levels. This study aimed to assess the feasibility of a novel noninvasive method to monitor transcutaneous partial pressure of CO₂ (P_CO2) (P_tcCO2) levels during EUS-guided drainage of peripancreatic fluid collections (PFCs). The safety of CO₂ insufflation in EUS-guided interventions was also investigated.

Patients and Methods:

Patients who underwent EUS-guided PFC drainage between September 2015 and December 2016 at Shengjing Hospital of China Medical University were prospectively enrolled in this study. P_tcCO2 was measured in all patients using a noninvasive sensor throughout the procedure.

Results:

There were 25 patients eligible to be included in this study. The mean procedure time was 53.1 min. The mean P_tcCO2 level was 40 ± 4 mmHg and 48 ± 5 mmHg before and after the procedure, respectively. The mean peak P_tcCO2 during the procedure was significantly higher at 53 ± 6 mmHg (P < 0.0001). No complications associated with CO₂ insufflation such as CO₂ narcosis, gas embolism, or arrhythmias were encountered.

Conclusions:

P_tcCO2 monitoring can accurately reflect the level of P_CO2 continuously and noninvasively. CO₂ insufflation is safe for patients undergoing relatively complicated EUS-guided drainage of PFCs.

Noninvasive Measurement of Carbon Dioxide during One-Lung Ventilation with Low Tidal Volume for Two Hours: End-Tidal versus Transcutaneous Techniques

BACKGROUND

There may be significant difference between measurement of end-tidal carbon dioxide partial pressure (PetCO2) and arterial carbon dioxide partial pressure (PaCO2) during one-lung ventilation with low tidal volume for thoracic surgeries. Transcutaneous carbon dioxide partial pressure (PtcCO2) monitoring can be used continuously to evaluate PaCO2 in a noninvasive fashion. In this study, we compared the accuracy between PetCO2 and PtcCO2 in predicting PaCO2 during prolonged one-lung ventilation with low tidal volume for thoracic surgeries.

METHODS

Eighteen adult patients who underwent thoracic surgeries with one-lung ventilation longer than two hours were included in this study. Their PetCO2, PtcCO2, and PaCO2 values were collected at five time points before and during one-lung ventilation. Agreement among measures was evaluated by Bland-Altman analysis.

RESULTS

Ninety sample sets were obtained. The bias and precision when PtcCO2 and PaCO2 were compared were 4.1 ± 6.5 mmHg during two-lung ventilation and 2.9 ± 6.1 mmHg during one-lung ventilation. Those when PetCO2 and PaCO2 were compared were -11.8 ± 6.4 mmHg during two-lung ventilation and -11.8 ± 4.9 mmHg during one-lung ventilation. The differences between PtcCO2 and PaCO2 were significantly lower than those between PetCO2 and PaCO2 at all five time-points (p < 0.05).

CONCLUSIONS

PtcCO2 monitoring was more accurate for predicting PaCO2 levels during prolonged one-lung ventilation with low tidal volume for patients undergoing thoracic surgeries.

Safety and efficacy of carbon dioxide insufflation during gastric endoscopic submucosal dissection

AIM: To compare the safety and efficacy of carbon dioxide (CO₂) and air insufflation during gastric endoscopic submucosal dissection (ESD).

METHODS: This study involved 116 patients who underwent gastric ESD between January and December 2009. After eliminating 29 patients who fit the exclusion criteria, 87 patients, without known pulmonary dysfunction, were randomized into the CO₂ insufflation (n = 36) or air insufflation (n = 51) groups. Standard ESD was performed with a CO₂ regulation unit (constant rate of 1.4 L/min) used for patients undergoing CO₂ insufflation. Patients received diazepam for conscious sedation and pentazocine for analgesia. Transcutaneous CO₂ tension (PtcCO₂) was recorded 15 min before, during, and after ESD with insufflation. PtcCO₂, the correlation between PtcCO₂ and procedure time, and ESD-related complications were compared between the two groups. Arterial blood gases were analyzed after ESD in the first 30 patients (12 with CO₂ and 18 with air insufflation) to assess the correlation between arterial blood CO₂ partial pressure (PaCO₂) and PtcCO₂.

RESULTS: There were no differences in respiratory functions, median sedative doses, or median procedure times between the groups. Similarly, there was no significant difference in post-ESD blood gas parameters, including PaCO₂, between the CO₂ and air groups (44.6 mmHg vs 45 mmHg). Both groups demonstrated median pH values of 7.36, and none of the patients exhibited acidemia. No significant differences were observed between the CO₂ and air groups with respect to baseline PtcCO₂ (39 mmHg vs 40 mmHg), peak PtcCO₂ during ESD (52 mmHg vs 51 mmHg), or median PtcCO₂ after ESD (50 mmHg vs 50 mmHg). There was a strong correlation between PaCO₂ and PtcCO₂ (r = 0.66; P < 0.001). The incidence of Mallory-Weiss tears was significantly lower with CO₂ insufflation than with air insufflation (0% vs 15.6%, P = 0.013). CO₂ insufflation did not cause any adverse events, such as CO₂ narcosis or gas embolisms.

CONCLUSION: CO₂ insufflation during gastric ESD results in similar blood gas levels as air insufflation, and also reduces the incidence of Mallory-Weiss tears.

Safety of carbon dioxide insufflation during gastric endoscopic submucosal dissection in patients with pulmonary dysfunction under conscious sedation

BACKGROUND

Carbon dioxide (CO2) insufflation is effective for gastric endoscopic submucosal dissection (ESD). However, its safety is unknown in patients with pulmonary dysfunction. This study aimed to investigate the safety of CO2 insufflation during gastric ESD in patients with pulmonary dysfunction under conscious sedation.

METHODS

We analyzed 322 consecutive patients undergoing ESD using CO2 insufflation (1.4 L/min) for gastric lesions. Pulmonary dysfunction was defined as a forced expiratory volume in 1.0 s/forced vital capacity (FEV1.0%) <70% or vital capacity <80%. Transcutaneous partial pressure of CO2 (PtcCO2) was recorded before, during, and after ESD.

RESULTS

In total, 127 patients (39%) had pulmonary dysfunction. There were no significant differences in baseline PtcCO2 before ESD, peak PtcCO2 during ESD, and median PtcCO2 after ESD between the pulmonary dysfunction group and normal group. There was a significant correlation between PtcCO2 elevation from baseline and ESD procedure time (r = 0.22, P < 0.05) only in the pulmonary dysfunction group. In patients with FEV1.0% <60%, the correlation was much stronger (r = 0.39, P < 0.05). Neither the complication incidences nor the hospital stay differed between the two groups. CO2 narcosis or gas embolism was not reported in either group.

CONCLUSIONS

CO2 insufflation during gastric ESD in patients with pulmonary dysfunction under conscious sedation is safe with regard to complication risk and hospital stay. However, in patients with severe obstructive lung disease, especially in those with FEV1.0% <60%, longer procedure time may induce CO2 retention, thus requiring CO2 monitoring.

Carbon dioxide monitoring during laparoscopic-assisted bariatric surgery in severely obese patients: transcutaneous versus end-tidal techniques

Various factors including severe obesity or increases in intra-abdominal pressure during laparoscopy can lead to inaccuracies in end-tidal carbon dioxide (PETCO2) monitoring. The current study prospectively compares ET and transcutaneous (TC) CO2 monitoring in severely obese adolescents and young adults during laparoscopic-assisted bariatric surgery. Carbon dioxide was measured with both ET and TC devices during insufflation and laparoscopic bariatric surgery. The differences between each measure (PETCO2 and TC-CO2) and the PaCO2 were compared using a non-paired t test, Fisher's exact test, and a Bland-Altman analysis. The study cohort included 25 adolescents with a mean body mass index of 50.2 kg/m2 undergoing laparoscopic bariatric surgery. There was no difference in the absolute difference between the TC-CO2 and PaCO2 (3.2±3.0 mmHg) and the absolute difference between the PETCO2 and PaCO2 (3.7±2.5 mmHg). The bias and precision were 0.3 and 4.3 mmHg for TC monitoring versus PaCO2 and 3.2 and 3.2 mmHg for ET monitoring versus PaCO2. In the young severely obese population both TC and PETCO2 monitoring can be used to effectively estimate PaCO2. The correlation of PaCO2 to TC-CO2 is good, and similar to the correlation of PaCO2 to PETCO2. In this population, both of these non-invasive measures of PaCO2 can be used to monitor ventilation and minimize arterial blood gas sampling.

Noninvasive monitoring of PaCO(2) during one-lung ventilation and minimal access surgery in adults: End-tidal versus transcutaneous techniques

Background:

Previous studies have suggested that end-tidal CO₂ (ET-CO₂) may be inaccurate during one-lung ventilation (OLV). This study was performed to compare the accuracy of the noninvasive monitoring of PCO₂ using transcutaneous CO₂ (TC-CO₂) with ET-CO₂ in patients undergoing video-assisted thoracoscopic surgery (VATS) during OLV.

Materials and Methods:

In adult patients undergoing thoracoscopic surgical procedures, PCO₂ was simultaneously measured with TC-CO₂ and ET-CO₂ devices and compared with PaCO₂.

Results:

The cohort for the study included 15 patients ranging in age from 19 to 71 years and in weight from 76 to 126 kg. During TLV, the difference between the TC-CO₂ and the PaCO₂ was 3.0 ± 1.8 mmHg and the difference between the ET-CO₂ and PaCO₂ was 6.2 ± 4.7 mmHg (P=0.02). Linear regression analysis of TC-CO2 vs. PaCO₂ resulted in an r² = 0.6280 and a slope = 0.7650 ± 0.1428, while linear regression analysis of ET-CO₂vs. PaCO₂ resulted in an r² = 0.05528 and a slope = 0.1986 ± 0.1883. During OLV, the difference between the TC-CO₂ and PaCO₂ was 3.5 ± 1.7 mmHg and the ET-CO₂ to PaCO₂ difference was 9.6 ± 3.6 mmHg (P=0.03 vs. ET-CO₂ to PaCO₂ difference during TLV; and P<0.0001 vs. TC-CO₂ to PaCO₂ difference during OLV). In 13 of the 15 patients, the TC-CO₂ value was closer to the actual PaCO₂ than the ET-CO₂ value (P =0.0001). Linear regression analysis of TC-CO₂vs. PaCO₂ resulted in an r² = 0.7827 and a slope = 0.8142 ± 0.0.07965, while linear regression analysis of ET-CO₂vs. PaCO₂ resulted in an r² = 0.2989 and a slope = 0.3026 ± 0.08605.

Conclusions:

During OLV, TC-CO₂ monitoring provides a better estimate of PaCO₂ than ET-CO2 in patients undergoing VATS.

Transcutaneous monitoring of partial pressure of carbon dioxide during endoscopic submucosal dissection of early colorectal neoplasia with carbon dioxide insufflation: a prospective study

BACKGROUND

The authors have reported that carbon dioxide (CO(2)) insufflation is safe and effective for lengthy endoscopic submucosal dissection (ESD) with the patient under conscious sedation. However, CO(2) monitoring has not been assessed to clarify whether partial pressure of carbon dioxide (PCO(2)) increases during this type of long procedure. This study aimed to monitor CO(2) before, during, and after ESD to investigate whether CO(2) insufflation is safe for patients receiving a lengthy ESD of early colorectal neoplasia under conscious sedation.

METHODS

This study prospectively enrolled 35 consecutive patients who underwent ESD at the National Cancer Center Hospital. Transcutaneous PCO(2) (PtcCO(2)) was measured with a noninvasive sensor before, during, and after ESD for patients under conscious sedation using midazolam.

RESULTS

The mean size of removed lesions was 44 ± 22 mm (range, 15-100 mm). The operation time was 90 ± 100 min (range, 15-600 mm). The dose of midazolam was 5.7 ± 4.0 mg (range, 2-19 mg). The mean PtcCO(2) was 41 ± 5 mmHg (range, 33-53 mmHg) before ESD and 44 ± 6 mmHg (range, 32-54 mmHg) afterward. The mean peak PtcCO(2) during ESD was 55 ± 7 mmHg (range, 39-78 mmHg), which was significantly higher than before or after ESD (p < 0.0001). However, no complication associated with CO(2) insufflation such as CO(2) narcosis, gas embolism, or arrhythmia needing treatment was seen in any of the cases.

CONCLUSIONS

This study suggests that CO(2) insufflation is safe for patients receiving a lengthy colorectal ESD under conscious sedation.

Transcutaneous monitoring of partial pressure of carbon dioxide during endoscopic submucosal dissection of early colorectal neoplasia with carbon dioxide insufflation: a prospective study

BACKGROUND

The authors have reported that carbon dioxide (CO(2)) insufflation is safe and effective for lengthy endoscopic submucosal dissection (ESD) with the patient under conscious sedation. However, CO(2) monitoring has not been assessed to clarify whether partial pressure of carbon dioxide (PCO(2)) increases during this type of long procedure. This study aimed to monitor CO(2) before, during, and after ESD to investigate whether CO(2) insufflation is safe for patients receiving a lengthy ESD of early colorectal neoplasia under conscious sedation.

METHODS

This study prospectively enrolled 35 consecutive patients who underwent ESD at the National Cancer Center Hospital. Transcutaneous PCO(2) (PtcCO(2)) was measured with a noninvasive sensor before, during, and after ESD for patients under conscious sedation using midazolam.

RESULTS

The mean size of removed lesions was 44 ± 22 mm (range, 15-100 mm). The operation time was 90 ± 100 min (range, 15-600 mm). The dose of midazolam was 5.7 ± 4.0 mg (range, 2-19 mg). The mean PtcCO(2) was 41 ± 5 mmHg (range, 33-53 mmHg) before ESD and 44 ± 6 mmHg (range, 32-54 mmHg) afterward. The mean peak PtcCO(2) during ESD was 55 ± 7 mmHg (range, 39-78 mmHg), which was significantly higher than before or after ESD (p < 0.0001). However, no complication associated with CO(2) insufflation such as CO(2) narcosis, gas embolism, or arrhythmia needing treatment was seen in any of the cases.

CONCLUSIONS

This study suggests that CO(2) insufflation is safe for patients receiving a lengthy colorectal ESD under conscious sedation.

Transcutaneous carbon dioxide monitoring in infants and children

OBJECTIVE

To review the technology required for and the applications of transcutaneous carbon dioxide (TC-CO2) monitoring in infants and children.

DATA SOURCE

A computerized, bibliographic search regarding the applications of transcutaneous carbon dioxide (TC-CO2) monitoring in infants and children.

RESULTS

Although the direct measurement of P(a)CO2 remains the gold standard, it provides only a single measurement of what is often a rapidly changing and evolving clinical picture. Given these concerns, there remains a clinical need for a means to continuously monitor P(a)CO2 without the need for repeated blood gas analysis. Although initially introduced into the neonatal intensive care unit; with improvements in the technology, TC-CO2 monitoring can now be used in infants, children and even adults. When compared with end-tidal carbon dioxide (ET-CO2) monitoring techniques, TC-CO2 monitoring has been shown to be equally as accurate in patients with normal respiratory function and more accurate in patients with shunt or ventilation-perfusion inequalities. TC-CO2 monitoring can be applied in situations that generally preclude ET-CO2 monitoring such as high frequency ventilation, apnea testing, and noninvasive ventilation. TC-CO2 monitoring has also been used in spontaneously breathing children with airway and respiratory issues such as croup and status asthmaticus as well as to monitor metabolic status during treatment of acidosis related to diabetic ketoacidosis.

CONCLUSIONS

Transcutaneous carbon dioxide monitoring may be a useful adjunct in various clinical scenarios in infants and children. It should be viewed as a complimentary technology and may be used in combination with ET-CO2 monitoring.

[Transcutaneous measurement of partial pressure of carbon dioxide and oxygen saturation: validation of the SenTec monitor]

OBJECTIVE

To validate a monitor for transcutaneous measurement of oxygen saturation (SpO2) and partial pressure of carbon dioxide (TcPCO2).

PATIENTS AND METHODS

This observational study included 140 Caucasian nonsmokers without jaundice. Patients underwent forced spirometry, measurement of SpO2 and TcPCO2 with the SenTec monitor, and arterial blood gas analysis (readings with 2 devices) during the stabilization phase of the monitor. In the statistical analysis, values from the 2 devices for measuring arterial blood gases were compared by mean differences for PaCO2 and oxygen saturation (SaO2). The arithmetic mean of the 2 blood gas measurements was calculated and relations between them and the SpO2 and TcPCO2 were assessed by the Pearson correlation coefficient (r) and the intraclass correlation coefficient (ICC) as a measure of agreement. Bland-Altman analysis was used to test data dispersion.

RESULTS

Ten patients were excluded due to a systematic error in the gas calibrator. The mean (SD) time to stabilization of the monitor before reading was 13.9 (2.4) minutes. The forced expiratory volume in the first second was greater than 80% in 40 patients, between 60% and 79% in 23, between 40% and 59% in 30, and less than 40% in 37. The mean (SD) differences between arterial blood gas measurements were 0.28 (1.0) mm Hg for PaCO2, -0.06% (0.86%) for SaO2, and -0.9 (2.7) mm Hg for PaO2. In the tests for correlation and agreement, r was 0.74 and ICC was 0.73 for SaO2 and SpO2; r was 0.92 and ICC was 0.92 for PaCO2 and TcPCO2. The subgroup analyses did not show any noteworthy differences. The Bland Altman analysis showed no significant dispersion. It was observed that the SenTec monitor underestimated oxygen saturation values by around 1% with respect to SaO2 and overestimated carbon dioxide pressure by 1 mm Hg with respect to PaCO2 values.

CONCLUSIONS

The stabilization time recommended for the SenTec monitor before taking a reading is 20 minutes. The overestimates and underestimates by the monitor are not clinically relevant. Finally, the values for SpO2 and TcPCO2 measured by the validated monitor are reliable.

Comparison of end-tidal and transcutaneous measures of carbon dioxide during general anaesthesia in severely obese adults

BACKGROUND

Patients with severe obesity (body mass index (BMI) greater than 35 kg x m(-2)) present difficulties for end-tidal carbon dioxide (FE'(CO(2))) monitoring. Previous studies suggest that transcutaneous (TC) carbon dioxide measurements could be valuable, so we compared FE' and TC measures with Pa(CO(2)) in severely obese patients during anaesthesia.

METHODS

We studied patients with severe obesity (BMI >or=40 kg x m(-2)) undergoing gastric bypass surgery. Carbon dioxide was measured with both FE' and TC devices. The difference between each measure (FE'(CO(2)) and TC-CO(2)) and the Pa(CO(2)) was averaged for each patient to provide one value, and data compared with a non-paired, two-way t-test, Fisher's exact test.

RESULTS

We studied 30 adults (aged 18-54 yr, mean 41, SD 8.0 yr; weight: 115-267 kg, mean 162, SD 35 kg). The absolute difference between the TC-CO(2) and Pa(CO(2)) was 0.2 (0.2) (mean, SD) kPa while the absolute difference between the FE'(CO(2)) and Pa(CO(2)) was 0.7 (0.4) kPa (P<0.0001). The bias and precision were +0.1 (0.3) kPa for TC vs arterial carbon dioxide and -0.7 (0.4) kPa for FE' vs arterial carbon dioxide.

CONCLUSIONS

Transcutaneous carbon dioxide monitoring provides a better estimate of Pa(CO(2)) than FE'(CO(2)) in patients with severe obesity.

Noninvasive carbon dioxide monitoring during one-lung ventilation: end-tidal versus transcutaneous techniques

OBJECTIVE

To compare transcutaneous CO(2) (TCCO(2)) and end-tidal CO(2) (ETCO(2)) monitoring during one-lung ventilation (OLV).

DESIGN

Prospective study.

SETTING

Operating room of a University Hospital.

PARTICIPANTS

Fifteen patients undergoing thoracic surgical procedures in whom one-lung ventilation was deemed necessary.

INTERVENTION

TC and ETCO(2) monitors were used simultaneously in the patients and compared with arterial blood gases (ABGs) during 2-lung ventilation and OLV.

MEASUREMENTS AND MAIN RESULTS

During 2-lung ventilation (TLV), the ET to PaCO(2) difference was 3.9 +/- 1.6 mmHg, whereas the TC to PaCO(2) difference was 2.5 +/- 0.8 mmHg (p = 0.0049). During OLV, the ET to PaCO(2) difference increased to 5.8 +/- 2.3 mmHg, whereas the TC to PaCO(2) difference was 2.7 +/- 1.4 mmHg (p = 0.0049 for ET to PaCO(2) difference during OLV v TLV and p = 0.0004 for ET to PaCO(2) gradient v TC to PaCO(2) gradient during OLV). During TLV, the difference between the ET and PaCO(2) was < or = 5 mmHg in 13 of 15 patients, whereas the difference between the TC and PaCO(2) was < or = 5 mmHg in 15 of 15 patients (p = not significant). During OLV, the difference between the ET and the PaCO(2) was < or = 5 mmHg in 6 of 15 patients, whereas the difference between the TC and PaCO(2) was < or = 5 mmHg in 14 of 15 patients (p = 0.0052, odds ratio 21.0 for ET v TC techniques and p = 0.02, odds ratio 9.75 for ET to PaCO(2) during TLV v OLV).

CONCLUSIONS

During OLV, TCCO(2) monitoring provides a more accurate estimate of PaCO(2) than ET techniques.

Anaesthesia, minimally invasive surgery and pregnancy

Minimally invasive surgery is being performed more frequently in pregnant patients. Numerous published reports have documented the safety and advantages of laparoscopic cholecystectomy and laparoscopic appendectomy during pregnancy. Pregnancy is associated with a variety of changes in the respiratory and cardiovascular systems, which make the parturient undergoing laparoscopic surgery particularly susceptible to hypoxia, hypercarbia and hypotension. This chapter provides a review of those physiological changes of pregnancy of particular concern for anaesthesiologists, and of the physiological responses to intra-abdominal carbon dioxide insufflation, not only in healthy patients, but also in the altered physiological state associated with pregnancy. We also describe our approach to anaesthetic management for minimally invasive surgery during pregnancy. With appropriate precautions, including vigilant monitoring and anticipation and treatment of the potential adverse effects of carbon dioxide pneumoperitoneum, anaesthesiologists may provide safe care for these patients, and pregnant women can benefit from the advantages of minimally invasive surgery.

Laparoscopic surgery during pregnancy

In the last decade, operative laparoscopic procedures are performed increasingly in both gynecology and general surgery. The major advantages of this newer minimally invasive approach are: decreased postoperative morbidity, less pain and decreased need for analgesics, early normal bowel function, shorter hospital stay, and early return to normal activity. With the advancement of laparoscopic surgery, its use during pregnancy is becoming more widely accepted. The most commonly reported laparoscopic operation during pregnancy is laparoscopic cholecystectomy (LC). Other laparoscopic procedures commonly performed during pregnancy include: management of adnexal mass, ovarian torsion, ovarian cystectomy, appendectomy, and ectopic pregnancy. The possible drawbacks of laparoscopic surgery during pregnancy may include injury of the pregnant uterus and the technical difficulty of laparoscopic surgery due to the growing mass of the gravid uterus. Also, the potential risk of decreased uterine blood flow secondary to the increase in intraabdominal pressure and the possible risk of carbon dioxide absorption to both the mother and fetus should be taken into account. To date, data on laparoscopic surgery during pregnancy are insufficient to draw conclusions on its safety and exact complication rate. This is due to the few cases reported and the lack of prospective studies. Furthermore, there is a common tendency to underreport unsuccessful cases. Finally, most reports in the literature come from centers and surgeons with special interest, experience, and skills in laparoscopy, and their results may not reflect the real complication rates. We have reviewed the pertinent English literature from the last decade. The cumulative experience suggests that laparoscopic surgery may be performed safely during pregnancy, although more studies are needed to establish its exact rate of adverse events.

Surgical management of biliary gallstone disease during pregnancy

BACKGROUND

Biliopancreatic gallstone disorders (BPD) manifesting during pregnancy are relatively rare. The management of these conditions remains controversial. Although perioperative problems and fetal loss have been reported, recent publications have advocated an early surgical approach.

PATIENTS AND METHODS

Thirty-two pregnant women underwent operation for BPD between January 1993 and December 1997. The mean age was 29 years and ranged from 18 to 41 years.

RESULTS

Twelve patients underwent a laparoscopic cholecystectomy (LC), and 20 open cholecystectomies (OC), including two conversions from laparoscopic. Seven of the OC patients required additional open CBD exploration and intraoperative choledochoscopy for CBD stones. No maternal mortality was observed. A single fetal demise (3%) occurred for a patient with gallstone pancreatitis who underwent open cholecystectomy during her 14th week of gestation.

CONCLUSIONS

Early involvement of the obstetric team, with preoperative and postoperative fetal monitoring, and adequate management of anesthetic and tocolytic agents make cholecystectomy a safe procedure at any stage of pregnancy.

Transcutaneous monitoring of carbon dioxide tension after cardiothoracic surgery in infants and children

In this prospective investigation, we evaluated the efficacy and accuracy of transcutaneous monitoring of CO2 (TC-CO2) in infants and children after cardiothoracic surgery. Cardiothoracic surgery patients whose ETCO2 and arterial CO2 values did not correlate (gradient > or = 5 mm Hg) during the first postoperative hour underwent placement of the TC electrode (30 of 33 patients). If the TC-CO2 to arterial difference was > or = 5 mm Hg, the TC-CO2 electrode was recalibrated and reapplied on another site. If the discrepancy was still > or =5 mm Hg, the case was considered a clinical failure and no further data were collected (3 of 30 patients). If the arterial to TC gradient was <5 mm Hg, the patient was included in the data collection (27 of 30 patients). One to five sample sets (TC and arterial CO2) were collected from these patients. Statistical analysis included linear regression analysis and Bland-Altman analysis. The cohort for the study included 27 patients ranging in age from 2 days to 9 yr and in weight from 3.2 to 25 kg. A total of 101 sample sets were analyzed. The mean +/- SD absolute difference between the TC-CO2 and arterial CO2 was 1.7 +/- 1.4 mm Hg (range 0-9 mm Hg). The TC-CO2 to arterial CO2 difference was 0-2 mm Hg in 82 of 101 values (81%), 35 mm Hg in 18 of 101 values (18%), and >6 mm Hg in 1 of 101 values (1%). Linear regression analysis revealed a slope of 0.90, an r value of 0.9410, and an r2 value of 0.8854 (P < 0.0001). Bland-Altman analysis revealed a bias of 0.58 mm Hg with a precision of +/- 2.1 mm Hg when comparing the TC-CO2 with the arterial CO2.

IMPLICATIONS

We conclude that, with certain caveats in mind, including the need to correlate the transcutaneous CO2 with an initial arterial CO2 value, transcutaneous CO2 monitoring can be used to estimate arterial CO2 in most neonates and children after cardiothoracic surgery.