Transcutaneous Carbon Dioxide Measurements Research Articles

Transcutaneous Carbon Dioxide Measurements in Women Receiving Intrathecal Morphine for Cesarean Delivery: A Prospective Observational Study

Neuraxial morphine is the most commonly used analgesic technique after cesarean delivery. The incidence of respiratory depression is reported to be very low (0%-1.2%) in this patient population as measured by pulse oximetry and respiratory rates. However, hypercapnia may be a more sensitive measure of respiratory depression. In the current study, the incidence of hypercapnia events (transcutaneous CO2 [TcCO2] >50 mm Hg) for ≥2-minute duration was evaluated using the Topological Oscillation Search with Kinematical Analysis monitor in women who received intrathecal morphine for postcesarean delivery analgesia. Healthy women (>37 weeks of gestation) scheduled for a cesarean delivery with spinal anesthesia with intrathecal morphine were recruited. Baseline STOP-BANG sleep apnea questionnaire and TcCO2 readings were obtained. Spinal anesthesia was initiated with 12 mg hyperbaric bupivacaine, 15 µg fentanyl, and 150 µg morphine. The Topological Oscillation Search with Kinematical Analysis monitor was reapplied in the postanesthesia care unit and TcCO2 measurements obtained for up to 24 hours. Supplemental opioid administration and adverse respiratory events were recorded. The primary outcome was the incidence of hypercapnia events, defined as a TcCO2 reading >50 mm Hg for ≥2 minutes in the first 24 hours after delivery. Of the 120 women who were recruited, 108 completed the study. Thirty-five women (32%; 99.15% confidence interval, 21%-45%) reached the primary outcome of a sustained hypercapnia event. The median time (interquartile range [IQR]) from intrathecal morphine administration to the hypercapnia event was 300 (124-691) minutes. The median (IQR) number of events was 3 (1-6) and longest duration of an event was 25.6 (8.4-98.7) minutes. Baseline median (IQR) TcCO2 measurements were 35 (30-0) mm Hg and postoperatively, median (IQR) TcCO2 measurements were 40 (36-43) mm Hg, a difference of 5 mm Hg (99.15% confidence interval of the difference 2-8 mm Hg, P < .001). The incidence of hypercapnia events was 5.4% in women with a baseline TcCO2 value ≤31 mm Hg, 22.5% with a baseline TcCO2 between 32 and 38 mm Hg, and 77.4% with a baseline TcCO2 >38 mm Hg (P < .001). Hypercapnia events (>50 mm Hg for ≥2-minute duration) occurred frequently in women receiving 150 μg intrathecal morphine for postcesarean analgesia. Higher baseline TcCO2 readings were observed in women who had hypercapnia events.

Transcutaneous versus blood carbon dioxide monitoring during acute noninvasive ventilation in the emergency department - a retrospective analysis.

Transcutaneous measurement of carbon dioxide (PtCO2) has been suggested as an alternative to invasively obtained PaCO2 for the monitoring of patients with hypercapnic respiratory failure during noninvasive ventilation (NIV). Current data on monitoring in hypoxaemic respiratory failure are scarce and show conflicting results in hypercapnic patients in the emergency department. We performed a retrospective comparison of real-time PtCO2 (SenTec Digital Monitor) and arterial/venous carbon dioxide tension (PaCO2/PvCO2) measurements in patients with severe hypoxaemic and/or hypercapnic respiratory failure during NIV. Agreement between PtCO2 and PaCO2/PvCO2 was the primary endpoint. Bland-Altman analysis and linear regression were used. 102 patients had at least one matched measurement of PtCO2 and PaCO2/PvCO2. For patients with arterial blood gas analysis, the mean difference was 0.46 kPa at baseline (95% confidence interval [CI] 0.23 to 0.60, limits of agreement 95% CI -0.54 to 1.45) and 0.12 kPa after NIV (95% CI -0.04 to 0.29, limits of agreement 95% CI: -0.61 to 0.86). The linear regression analysis found a correlation R2 of 0.88 (p <0.001) at baseline and an R2 of 0.99 (p <0.001) after initiating NIV. For patients with venous blood gas analysis, the mean difference was 0.64 kPa at baseline (95% CI 0.04 to 1.24, limits of agreement 95% CI -0.72 to 2) and 0.80 kPa after NIV (95% CI 0.51 to 1.10, limits of agreement 95% CI 0.29 to 1.32), R2 0.78 (p <0.001) at baseline and R2 0.91 (p <0.001) after initiating NIV. A PaCO2/PvCO2 >8 kPa was associated with a lesser degree of agreement between the levels of PtCO2 and PaCO2/PvCO2 (p <0.001). Transcutaneous PCO2 monitoring shows a good concordance with PaCO2 and is a reliable, feasible, patient-friendly and safe alternative to repeated blood gas analysis for patients with severe hypoxaemic and/or hypercapnic respiratory failure receiving emergency NIV in the emergency department. An initial blood gas analysis to evaluate the respiratory and metabolic state and to rule out a significant discrepancy compared with the transcutaneous measurement is recommended.

Accuracy of Transcutaneous Carbon Dioxide Measurement in Premature Infants.

Background. In premature infants, maintaining blood partial pressure of carbon dioxide (pCO2) value within a narrow range is important to avoid cerebral lesions. The aim of this study was to assess the accuracy of a noninvasive transcutaneous method (TcpCO2), compared to blood partial pressure of carbon dioxide (pCO2). Methods. Retrospective observational study in a tertiary neonatal intensive care unit. We analyzed the correlation between blood pCO2 and transcutaneous values and the accuracy between the trends of blood pCO2 and TcpCO2 in all consecutive premature infants born at <33 weeks' gestational age. Results. 248 infants were included (median gestational age: 29 + 5 weeks and median birth weight: 1250 g), providing 1365 pairs of TcpCO2 and blood pCO2 values. Pearson's R correlation between these values was 0.58. The mean bias was −0.93 kPa with a 95% confidence limit of agreement of −4.05 to +2.16 kPa. Correlation between the trends of TcpCO2 and blood pCO2 values was good in only 39.6%. Conclusions. In premature infants, TcpCO2 was poorly correlated to blood pCO2, with a wide limit of agreement. Furthermore, concordance between trends was equally low. We warn about clinical decision-making on TcpCO2 alone when used as continuous monitoring.

Agreement of Mixed Venous Carbon Dioxide Tension (PvCO2) and Transcutaneous Carbon Dioxide (PtCO2) Measurements in Ventilated Infants.

Background:Noninvasive transcutaneous carbon dioxide monitoring has been shown to be accurate in infants and children, limited data are available to show the usefulness and limitations of partial transcutaneous carbon dioxide tension (PtCO2) value.Objectives:The current study prospectively determines the effectiveness and accuracy of PtCO2 measurements in newborns.Materials and Methods:Venous blood gas sampling and monitoring of the PtCO2 level (TCM TOSCA, Radiometer) were done simultaneously. All measurements are performed on mechanically ventilated infants. Partial venous carbon dioxide tension (PvCO2) values divided into three groups according to hypocapnia (Group 1: < 4.68 kPa), normocapnia (Group 2: 4.68–7.33 kPa), hypercapnia (Group 3: > 7.33 kPa) and then PvCO2 and PtCO2 data within each group were compared separately.Results:A total of 168 measurements of each PvCO2 and PtCO2 data were compared in three separated groups simultaneously (13 in Group 1, 118 in Group 2, and 37 in Group 3). A bias of more than ± 0.7 kPa was considered unacceptable. PtCO2 was related to PvCO2 with acceptable results between the two measurements in hypocapnia (mean difference 0.20 ± 0.19 kPa) and normocapnia (0.002 ± 0.30 kPa) groups. On the other hand in hypercapnia group PtCO2 values were statistically significant (P < 0.001) and lower than PvCO2 data (mean difference 0.81 ± 1.19 kPa)Conclusions:PtCO2 measurements have generally good agreement with PvCO2 in hypocapnic and normocapnic intubated infants but there are some limitations especially with high level of CO2 tension. Monitoring of PtCO2 is generally a useful non-invasive indicator of PvCO2 in hypocapnic and normocapnic infants.

1107 Continuous Carbon Dioxide Monitoring Using Features Of Neonatal Electroencephalography

BackgroundThe continuous monitoring of partial pressure of blood carbon dioxide (pCO2) in premature babies has proven to be challenging. Spot measurements of pCO2 can be performed by taking a blood...

Infraclavicular sensor site: A new promising site for transcutaneous capnography

Background. Transcutaneous measurement of carbon dioxide is routinely done at the earlobe site. In patients receiving non invasive ventilation or in the intensive care setting with necklines, an alternate measurement site would be useful. We started to use the infraclavicular site for transcutaneous measurements of carbon dioxide using a new digital sensor. Aim. Comparison of transcutaneous carbon dioxide with arterial carbon dioxide at the infraclavicular site. Methods. We retrospectively compared transcutaneous carbon dioxide at the infraclavicular site with arterial carbon dioxide in 50 samples. The Sentec Digital Monitoring System (Sentec AG, Therwil, Switzerland) was used. The V-Sign digital sensor was placed on the infraclavicular site at the medial two third and one third point from the sternoclavicular joint and acromioclavicular joint. Results. When comparing PcCO2 with PaCO2 values, the Bland-Altman analysis revealed a bias of 0.02 kPa (95% CI: [− 0.1; 0.14]) with a precision of 0.42 kPa. Linear regression analysis describes the relationship between the two methods. The slope of the linear model was 0.85 ± 0.04 and the intercept was 0.77 ± 0.21 (RSE = 0.37 , R2 = 0.91). Conclusion. The measurement of transcutaneous carbon dioxide at the infraclavicular site is feasible with a digital sensor and has a good correlation with the carbon dioxide values obtained from the arterial blood gas. The findings of the current study form the basis for further clinical studies for its regular application in clinical use.

Detection of hypoventilation during deep sedation in patients undergoing ambulatory gynaecological hysteroscopy: a comparison between transcutaneous and nasal end-tidal carbon dioxide measurements

Detection of hypoventilation during deep sedation in patients undergoing ambulatory gynaecological hysteroscopy: a comparison between transcutaneous and nasal end-tidal carbon dioxide measurements

504 Effects of Reduced Electrode Temperature on the Accuracy and Precision of Transcutaneous Carbon Dioxide Measurements

Background and aims: The harmful effect of hypocapnia on the neonatal brain emphasizes the importance of monitoring arterial carbon dioxide tension (PaCO2). Transcutaneous monitoring of carbon dioxide (tcPCO2) reduces need of arterial blood sampling. Drawbacks are high electrode temperature causing short application time and risks of skin burning. The aim of this study was to determine the accuracy and precision of tcPCO2 at reduced electrode temperature.Methods: Forty newborns (GA 24.9- 41.7) were included. Two tc-monitors were applied (TCM4, Radiometer, Copenhagen). The metabolic constant was 0.53 kPa. Arterial blood gas sampling and recording of the tcPCO2-level at different electrode temperatures was done simultaneously (39°C, 40°C, 41°C, 42°C, 44°C). The Bland and Altman method was used for analysis. PaCO2-tcPCO2 difference was expressed in fraction of the mean.Results: Mean PaCO2 was 5.8 kPa {3,2; 7.9}. The mean PaCO2 - tcPCO2 difference (bias) increased from 5% at 44°C to 17% at 39°C, but did not differ significantly between 41°C and 40°C (14.8% vs. 11.8%). The precision of the tcPCO2 at each temperature ranged from +7% to +10%. After correction for the temperature-dependent overreading, the Bland-Altman plot showed increasing PaCO2 - tcPCO2 difference with increasing PaCO2, approx. 2% pr. kPa increase of CO2. Sequence of electrode temperatures did not matter. Only mild transient erythema was observed.Conclusions: A lower electrode temperature in tcPCO2-monitoring increases systematic overreading of the tc-electrode. However, in very preterm babies, monitoring at 40°C or 41°C is possible provided bias correction of 12-15%.

Detection of hypoventilation during deep sedation in patients undergoing ambulatory gynaecological hysteroscopy: a comparison between transcutaneous and nasal end-tidal carbon dioxide measurements

BackgroundTranscutaneous measurement of carbon dioxide (Tcco2) provides a non-invasive estimation of arterial carbon dioxide (Paco2). Nasal capnography (Pe′co2) is used to assess ventilation during monitored anaesthesia care (MAC) with sedation since it can readily detect apnoea. We compared the agreement between Tcco2 and Pe′co2 with Paco2 and the ability to detect hypercarbia in patients under deep sedation. MethodsForty healthy female subjects receiving deep sedation for hysteroscopy were studied. A Tcco2 (TOSCA 500, Radiometer, Inc., Westlake, OH, USA) electrode was applied to the earlobe and Pe′co2 capnography was monitored using nasal side-stream sampling. All subjects received oxygen (3 litre min−1). Subjects were evaluated at intervals using a modified Ramsay sedation score until they reached a score ≥5. Arterial blood gas values were compared with Tcco2 and Pe′co2 values. Bland–Altman, linear regression, and receiver operator characteristics analysis were performed. ResultsThe mean (sd) absolute difference between the Tcco2, Pe′co2, and the Paco2 were 0.43 (0.35) and 1.06 (0.8) kPa, respectively (P=0.002). Tcco2 demonstrated a mean bias (2 sd) of 0.23 (0.07–0.4) kPa with Paco2 compared with −0.93 (−1.24 to −0.63) kPa for Pe′co2. One minute before blood sampling, the sensitivity of the Tcco2 monitor for detecting Paco2 >6.65 kPa was greater than for Pe′co2 (66.7% vs 33.3%, P<0.01). ConclusionsTcco2 demonstrated better agreement with Paco2 than Pe′co2 for patients under MAC with deep sedation. Tcco2 monitoring was more sensitive for detection of Paco2 >6.65 kPa than Pe′co2.

Weaning Mechanical Ventilation After Off-Pump Coronary Artery Bypass Graft Procedures Directed by Noninvasive Gas Measurements

Partial pressure of carbon dioxide and oxygen were transcutaneously measured in adults after off-pump coronary artery bypass (OPCAB) surgery. The clinical use of such measurements and interchangeability with arterial blood gas measurements for weaning patients from postoperative mechanical ventilation were assessed. This was a prospective observational study. Tertiary referral heart hospital. Postoperative OPCAB surgical patients. Transcutaneous oxygen and carbon dioxide measurements. In this prospective observational study, 32 consecutive adult patients in a tertiary care medical center underwent OPCAB surgery. Noninvasive measurement of respiratory gases was performed during the postoperative period and compared with arterial blood gases. The investigator was blinded to the reports of arterial blood gas studies and weaned patients using a "weaning protocol" based on transcutaneous gas measurement. The number of patients successfully weaned based on transcutaneous measurements and the number of times the weaning process was held up were noted. A total of 212 samples (pairs of arterial and transcutaneous values of oxygen and carbon dioxide) were obtained from 32 patients. Bland-Altman plots and mountain plots were used to analyze the interchangeability of the data. Twenty-five (79%) of the patients were weaned from the ventilator based on transcutaneous gas measurements alone. Transcutaneous carbon dioxide measurements were found to be interchangeable with arterial carbon dioxide during 96% of measurements, versus 79% for oxygen measurements. More than three fourths of the patients were weaned from mechanical ventilation and extubated based on transcutaneous gas values alone after OPCAB surgery. The noninvasive transcutaneous carbon dioxide measurement can be used as a surrogate for arterial carbon dioxide measurement to manage postoperative OPCAB patients.

Early non invasive detection of hypercarbia in two cardiac surgical patients

The availability of transcutaneous monitors has provided a means of non invasive assessment of CO(2) tension and a trend of the ventilation status commonly in infants and neonates. The authors describe two cases of hypercapnia diagnosed early in adults by the non invasive transcutaneous measurement of carbon dioxide (tcpCO(2)) using TINA TCM4 in postoperative cardiac surgical patients who were mechanically ventilated. Curiously, this increase in tcpCO(2) levels was associated with a false increase in the tcpO(2) values though no changes in the ventilatory parameters to increase oxygenation were made. The probable mechanism of the increase in tcpO(2) levels with hypercarbia is discussed.

Overnight features of transcutaneous carbon dioxide measurement as predictors of metabolic status

To systematically investigate whether overnight features in transcutaneous carbon dioxide (P(TcCO(2)) measurements can predict metabolic variables in subject with suspected sleep-disordered breathing. The features extracted from the P(TcCO(2)) signal included the number of abrupt descents per hour and attributes that characterize the recovery after such an event. For each outcome variable, the subgroup of the 108 study subjects with the particular variable present was divided into two representative classes, and the optimal features that can predict the classes were learned. Overfitting was avoided by evaluating the classification algorithms using 10-fold cross-validation. (P(TcCO(2)) signal has a key role in determining the classes of high-density lipoprotein cholesterol and thyroid-stimulating hormone concentrations, and it improves the classification accuracy of glycosylated hemoglobin A1c and fasting plasma glucose values. The features learned from the (P(TcCO(2)) signal reflected the state of the selected metabolic variables in a subtle, but systematic, way. These findings provide a step towards understanding how metabolic disturbances are connected to carbon dioxide exchange during sleep.

Parameter estimation of a respiratory control model from noninvasive carbon dioxide measurements during sleep

A new method for estimating the parameters of a human gas exchange model is presented. Sensitivity analysis is used both to inspect the relative importance of the model parameters and to speed up the par-ameter estimation process. Multistart optimization is used to compensate for the effects of partial and noisy measurements. The validity of the method is first investigated with a test problem for which par-ameter identifiability is shown. The method is then applied to the estimation of sleep-related changes in the respiratory control system from the end-tidal and transcutaneous carbon dioxide measurements on human subjects. The results show that it is possible to gain insight into the behaviour of the rather complex physiological system using only a few noninvasive measurements and tractable computations.

Clinical application of transcutaneus blood gas monitoring on axial pattern flaps

目的 探讨经皮氧及二氧化碳分压在动态监测皮瓣血供中的应用意义方法 2001年8月至2003年11月,应用经皮血气分析技术,对56例复合组织皮瓣进行动态血供监测. 结果 56例皮瓣中,6例在术后监测4～10 h发生血管栓塞,再手术成活5例,抢救成功率83.33%. 结论该方法能够敏感、客观、连续定量的反映皮瓣的灌注状况,是移植术后早期理想的血运监测手段。

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

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

Transcutaneous Carbon Dioxide Measurement During Apnea Testing in Pediatric Patients

Transcutaneous Carbon Dioxide Measurement During Apnea Testing in Pediatric Patients

Transcutaneous Carbon Dioxide Measurement During Apnea Testing in Pediatric Patients

Several variables affect the rate at which PaCO2 increases during apnea testing in the determination of brain death. In many cases, arterial blood gases (ABGs) are obtained at predetermined times in an attempt to demonstrate a PaCO2 value greater than 60 mmHg. This practice may result in the need to obtain multiple ABGs, terminating the apnea test before the PaCO2 is 60 mmHg, or waiting too long with a resultant compromise of hemodynamic status or arterial desaturation. We have found that transcutaneous CO2 (TC-CO2) monitoring can be used to guide the time to obtain ABGs during apnea testing. TC-CO2 monitoring was used during apnea testing in eight patients ranging in age from 1 to 16 years. In patients 1 and 2, when an ABG was obtained when the TC-CO2 value equaled 60 mmHg, the PaCO2 was less than 60 mmHg in all four cases (one ABG drawn for each apnea test in the two patients). When an ABG was obtained with the TC-CO2 value equal to 70 mmHg (n = 16), the TC-CO2 to PaCO2 difference was 2–11 mmHg (5.8 ± 2.7 mmHg) and the PaCO2 ranged from 59 to 72 mmHg (64.4 ± 3.2 mmHg). When an ABG was obtained with the TC-CO2 value equal to 80 mmHg (n = 14), the TC-CO2 to PaCO2 difference was 2–8 mmHg (5.4 ±1.9 mmHg) and the PaCO2 ranged from 72 to 83 mmHg (75.4 ± 32 mmHg). TC-CO2 monitoring can be used to help judge the timing of ABG analysis during apnea testing in children. When the TC-CO2 value reached 70 mmHg, we noted that the PaCO2 was greater than 60 mmHg in 15 of 16 cases.

喉頭手術での経皮炭酸ガスモニタの有用性

To investigate the accuracy and usefulness of combined transcutaneous carbon dioxide (PtcCO2) and oxygen (PtcO2) measurement compared with arterial blood gas analysis (PaCO2 and PaO2), 10 patients undergoing laryngomicrosurgery under total intravenous anesthesia were studied. The PtcCO2 values revealed a high degree of correlation with PaCO2 during anesthesia (r=0.96) and after anesthesia (r=0.93). The PaO2 values revealed a generally good correlation with PaO2 during anesthesia (r=0.81), but not after anesthesia (r=0.23). Capnography values are invalid after anesthesia, and an arterial catheter is not always indicated and feasible in microlaryngoscopy. Transcutaneous devices provide an effective method for the non-invasive monitoring of PCO2 during and after anesthesia, in situations whereas continuous, precise control of CO2 levels is desired such as laryngomicrosurgery.

The usefulness of transcutaneous carbon dioxide measurement in patients undergoing gynecological laparoscopic surgery

The usefulness of transcutaneous carbon dioxide measurement in patients undergoing gynecological laparoscopic surgery

Transcutaneous carbon dioxide measurement after craniotomy in spontaneously breathing patients.

The purpose of this study was to determine the incidence of postoperative hypercarbia in patients undergoing intracranial neurosurgery. Postoperative hypercarbia is a well-recognized cause of postoperative morbidity. Sixty-four patients undergoing craniotomy were monitored in the first 36 postoperative hours using transcutaneous CO2 monitoring. We collected and analyzed demographic data, complete medical histories and examinations, and details of surgery, anesthesia, and postoperative progress. The accuracy of the transcutaneous CO2 monitoring was evaluated by comparison with arterial blood gas CO2. The "TINA" TCM3 Transcutaneous CO2 Monitor (Radiometer, Copenhagen, Denmark) was used. Thirty-nine patients (61%) developed no hypercarbia. Nineteen patients (30%) developed mild to moderate hypercarbia (46-59 mm Hg) and six patients (9%) developed severe hypercarbia (60 mm Hg or greater). Statistically significant differences were observed between the severely hypercarbic group and the other two groups combined, as follows: a higher incidence of preoperative and postoperative seizures, a lower average postoperative Glasgow Coma Scale score, a higher incidence of reintubation and ventilation, and a higher degree of intraoperative brain disturbance. Analysis of transcutaneous CO2 measurements and time-matched arterial blood gas CO2 measurements revealed an acceptable accuracy of the transcutaneous method. this study demonstrates that, in routine neurosurgical practice, a subgroup of patients are at risk of developing postoperative hypercarbia, which may be more common than is generally recognized and will not usually be detected by routine postoperative monitoring. Transcutaneous CO2 monitoring is a useful technique that may impact management decisions.