Transcutaneous CO2 Research Articles

O049 Sleep quality and its impact on children with primary ciliary dyskinesia

Abstract Background PCD is a rare, progressive disease resulting in upper respiratory manifestations and abnormal lung mechanics that increase one’s risk of obstructive sleep apnoea. This study aims to characterise the sleep quality of children with PCD and its impacts on mood and HRQOL. Methods Children with PCD aged 0–19 years with stable respiratory symptoms were recruited. Subjective sleep quality was assessed by the Sleep Disturbance Scale for Children (SDSC), OSA-18, and Paediatric Daytime Sleepiness Scale (PDSS). Mood and depressive symptoms were assessed via QOL-PCD and Children’s Depressive Inventory (CDI) as age-appropriate. Pulmonary function testing was performed via spirometry and Multiple Breath Washout. Patients underwent an ENT assessment. All children completed one night of polysomnography including transcutaneous CO2 and video monitoring. Progress to date: Twenty participants (45% female) have been recruited with a mean age of 8.5 years. Mean (±SD) FEV1 is 76.5±22.9%. 73% of children assessed have chronic rhinosinusitis. Clinically significant scores for SDSC were observed in 79% of patients and in 30% of patients for OSA-18. 38% of children reported clinically significant scores for PDSS. To date, 7 children have completed polysomnography. Intended outcome and impact: This is the first study to characterise sleep quality and the impact of sleep disturbance in Australian children with PCD. We aim to identify clinical markers of poor sleep quality to better inform the development of a sleep screening program for use in paediatric PCD clinics.

Evaluation of the Relationship between Transcutaneous Carbondioxide Monitorization and End-tidal Carbondioxide and Partial Carbondioxide Monitorization

MonitorizationNon-invasive methods have replaced invasive methods in line with developments in pediatric intensive care units. (Especially methods that enable continuous monitoring) Although arterial carbon dioxide measurement is still the gold standard for the evaluation of alveolar ventilation, the need for continuous monitoring of PaCO2 and the invasive nature of this method have led to the investigation of alternative methods. To evaluate the correlation of transcutaneous CO2 (TcCO2) monitoring with PaCO2 and ETCO2 in mechanically ventilated patients in peditaric intensive care units. Single-center, prospective, observational cohort study. We enrolled 60 patients between the age of 1 month-18 years who were mechanically ventilated in pediatric intensive care unit for this single-center, prospective, observational cohort study from February 2019 through March 2019. Correlation analysis was performed for arterial PaCO2, end-tidal CO2, TcCO2 parameters. P<0.05 values were considered significant. The Bland-Altman plot was created for determining the agreement between the methods. The correlation of transcutaneous CO2 and end-tidal CO2 with arterial PaCO2 was evaluated, both parameters were found to be positively and highly correlated (r=0.864, p<0.001, r:0.962, p<0.001, respectively). The mean bias between the arterial carbondioxide mesaurement and transcutaneous measurement was 5.5, and limits of agreement (bias ±1.96 SD) ranged from -13.9 to 2.9. The mean bias between the arterial carbondioxide mesaurement and end-tidal carbondioxide measurement was 2.3, and limits of agreement (bias ±1.96 SD) ranged from -4.1 to 8.6. In 44 measurements (88%), the TcCO2 was ±7.5 mm Hg of the PaCO2. TcCO2 seems to be a good alternative for carbon dioxide measurement, as it is non-invasive and allows continuous monitoring in view of today's intensive care conditions, but arterial PaCO2 measurement is still the gold standard method. Continuous TcCO2 monitoring provides a promising alternative to repeated blood sampling in subjects requiring mechanical ventilation for critically ill children.

Wearable Transcutaneous CO2 Monitor Based on Miniaturized Nondispersive Infrared Sensor.

Transcutaneous oxygen and carbon dioxide provide the status of pulmonary gas exchange and are of importance in diagnosis and management of respiratory diseases. Though significant progress has been made in oximetry, not much has been explored in developing wearable technologies for continuous monitoring of transcutaneous carbon dioxide. This research reports the development of a truly wearable sensor for continuous monitoring of transcutaneous carbon dioxide using miniaturized nondispersive infrared sensor augmented by hydrophobic membrane to address the humidity interference. The wearable transcutaneous CO2 monitor shows well-behaved response curve to humid CO2 with linear response to CO2 concentration. The profile of transcutaneous CO2 monitored by the wearable device correlates well with the end-tidal CO2 trend in human test. The feasibility of the wearable device for passive and unobstructed tracking of transcutaneous CO2 in free-living conditions has also been demonstrated in field test. The wearable transcutaneous CO2 monitoring technology developed in this research can be widely used in remote assessment of pulmonary gas exchange efficiency for patients with respiratory diseases, such as COVID-19, sleep apnea, and chronic obstructive pulmonary disease (COPD).

The Effect of Transcutaneous Application of Gaseous CO2 on Diabetic Symmetrical Peripheral Neuropathy—A Double-Blind Randomized Clinical Trial

Aim: Diabetic symmetrical peripheral neuropathy is a common complication of diabetes mellitus. Patients treated with transcutaneous CO2 application for chronic wounds reported an improvement in peripheral sensations. This study aimed to evaluate the effect of transcutaneous application of gaseous CO2 on diabetic symmetrical peripheral neuropathy. Methods: A prospective randomized, double-blind study was performed at the University Medical Center Ljubljana between September 2019 and September 2020. Sixty consecutive patients with diabetes with a unilateral chronic wound were randomized into either a study group that received transcutaneous CO2 therapy or a control group that received placebo treatment with air. Results: Vibration, monofilament sensation, and temperature of the big toe improved significantly in the study group (p < 0.001, for vibration sensation, monofilament test and temperature of the big toe), but not in the control group (p = ns for all evaluated outcomes). Conclusion: According to our results, a transcutaneous application of gaseous CO2 shows promising results in treating diabetic symmetrical peripheral neuropathy. Considering the major consequences of sensory loss leading to foot ulceration and possibly amputation, we believe this treatment approach deserves future attention and investigation as a treatment modality of diabetic symmetrical peripheral neuropathy.

Obstructing Sleep Apnea in Children with Genetic Disorders-A Special Need for Early Multidisciplinary Diagnosis and Treatment.

Background—Children with genetic disorders have multiple anatomical and physiological conditions that predispose them to obstructive sleep apnea syndrome (OSAS). They should have priority access to polysomnography (PSG) before establishing their therapeutic protocol. We analyzed the prevalence and the severity of OSAS in a particular group of children with genetic disorders and strengthened their need for a multidisciplinary diagnosis and adapted management. Methods—The retrospective analysis included children with genetic impairments and sleep disturbances that were referred for polysomnography. We collected respiratory parameters from sleep studies: apnea–hypopnea index (AHI), SatO2 nadir, end-tidal CO2, and transcutaneous CO2. Subsequent management included non-invasive ventilation (NIV) or otorhinolaryngological (ENT) surgery of the upper airway. Results—We identified 108 patients with neuromuscular disorders or multiple congenital anomalies. OSAS was present in 87 patients (80.5%), 3 of whom received CPAP, 32 needed another form of NIV during sleep, and 15 patients were referred for ENT surgery. The post-therapeutic follow-up PSG parameters confirmed the success of the treatment. Conclusions—The upper airway obstruction diagnostics and management for children with complex genetic diseases need a multidisciplinary approach. Early detection and treatment of sleep-disordered breathing in children with genetic disorders is a priority for improving their quality of life.

793 Obstructive Sleep Apnea and Hypoventilation in Patients with Muscular Dystrophies: Analysis of 42 Polysomnogram Studies

Abstract Introduction Patients with muscular dystrophies (dystrophinopathy, congenital muscular dystrophy and limb-girdle muscular dystrophy) are at greater risk of obstructive sleep apnea (OSA). However, few studies have examined if they are also at risk for hypoventilation and its relationship with OSA. We hypothesize that these two conditions occur independently of each other as an impaired ventilator drive and diaphragm weakness. Methods Retrospective review of diagnostic polysomnograms (PSG) in a tertiary care facility over 15 years was conducted. The polysomnography included either end tidal CO2 or transcutaneous CO2 measurements. Descriptive data analysis was performed on results described. We computed Pearson correlation coefficients to examine the relationships between PSG indices and other parameters. Pearson’s Chi-squared test with Yates’ continuity correction is used to test if hypoventilation is independent from OSA. Results 42 PSG studies in patients with muscular dystrophies were included after excluding 2 studies due to insufficient sleep duration. The average age at the time of study was 14.2 yrs with 41 being male and average BMI of 24.1. 64% of the group met the definition for OSA with average AHI 8.0. 36% of the group met the criteria for hypoventilation, and 33% patients with hypoventilation did not have OSA. Chi squared analysis (p=1.0) shows that hypoventilation is independent of OSA. Conclusion Sleep disordered breathing is common in patients with muscular dystrophy. This study supports that OSA and CO2 retention may be independent processes. Support (if any):

848 Refractory Hypoventilation in Congenital Central Hypoventilation Syndrome: A Case for Average Volume-Assured Pressure Support

Abstract Introduction Congenital Central Hypoventilation Syndrome (CCHS) is a rare cause of alveolar hypoventilation in children resulting in lifelong ventilatory support. In older children requiring nocturnal support alone, the use of diaphragmatic pacing in conjunction with or independent of non-invasive ventilatory (NIV) support has been demonstrated to improve quality of life. We present a case of refractory hypoventilation despite escalation of NIV. Report of case(s) 20-year-old female with Hirschsprung’s disease and CCHS (20/26 polyalanine repeats) with history of invasive ventilation via tracheostomy who underwent bilateral diaphragmatic phrenic nerve stimulator placement at 13 years-of-age with subsequent tracheostomy decannulation. Diaphragmatic pacing was discontinued three years later in the setting of pneumonia and patient discomfort because of receiver positioning. At that time, she had improved subjective sleep quality and adequate ventilatory support on bi-level positive airway pressure (PAP) despite discontinuation of diaphragmatic pacing. Titration of bi-level PAP was done via polysomnogram four years later demonstrating nocturnal hypoventilation with transcutaneous CO2 values greater than 50 mmHg for 80% of the study and an oxygen nadir of 87% despite titration of inspiratory pressure and respiratory rate to maximize ventilatory assistance. The patient was subsequently admitted to the intensive care unit for transition to non-invasive average volume-assured pressure support (AVAPS) mode. Ventilation improved with nocturnal pCO2 values via capillary blood gas of 31 mmHg and 45 mmHg at 2 am and 6 am respectively. The patient was discharged on AVAPS therapy while undergoing evaluation to resume diaphragmatic pacing via cervical phrenic nerve stimulators for improved comfort. Conclusion Several ventilatory strategies may be employed in the care of patients with CCHS, with individualization of support based on phenotype, comorbidities, and patient and family preference. This case highlights the unique challenges of adequately ventilating patients as they age. The use of NIV via an AVAPS mode in patients with CCHS has been infrequently reported in the literature, though is promising in reported efficacy with regards to ensured ventilation. This, in conjunction with diaphragmatic pacing, may allow patients to achieve appropriate ventilation while maintaining quality of life, and could be considered in patients with refractory hypoventilation despite other modes of NIV. Support (if any):

846 Pulmonary Arterial Hypertension as a Sequela of Untreated Obstructive Sleep Apnea in a Patient with Prader-Willi Syndrome

Abstract Introduction Prader-Willi Syndrome (PWS) is a complex neurogenetic disorder characterized by hypotonia, behavioral problems, endocrinopathies, sleep and respiratory abnormalities. Morbidity and mortality in the PWS population is attributable to obesity, cardiovascular problems, and sleep apnea. We report a patient with PWS presenting with pulmonary arterial hypertension (PAH) due to untreated obstructive sleep apnea (OSA). Report of case(s) Our patient is a 17-year-old female with a past medical history of PWS, scoliosis, obesity (BMI 52.46), hypogonadotropic hypogonadism, and type II diabetes. Baseline echocardiogram (ECHO) performed at age 9 revealed an estimated right ventricular systolic pressure (eRVSP) of 32mmHg above right atrial pressure (RAP), tricuspid regurgitation (TR) at 2.8 m/sec with no interventricular septal flattening (IVSF) and right ventricle (RV) systolic dysfunction suggestive of mild PAH. Given significant scoliosis the patient did not qualify for growth hormone therapy. She underwent a polysomnogram (PSG) at age 14 showing severe obstructive sleep apnea; apnea-hypopnea index (AHI) of 22.6 (oAHI 22.6). Patient was subsequently lost to follow up until presenting in acute respiratory failure at age 17. She required endotracheal intubation and was extubated to bilevel PAP (BPAP) with inability to wean off BPAP. At that time an ECHO revealed eRVSP of 55 mmHg above RAP, IVSF, TR at 3.7 m/sec, and RV systolic dysfunction suggestive of moderate to severe PAH and developing right sided heart failure. A PAP titration PSG during this admission revealed hypoxemia with oxygen saturation less than 90% (O2 nadir 70%) 12.6% of total sleep time (TST) and hypoventilation (transcutaneous CO2 max of 57 mmHg with an elevation above 50 mmHg for 100% of TST). Using an inspiratory PAP (IPAP) of 24 cmH2O and expiratory PAP (EPAP) of 14 cmH20 with supplemental O2 of 4LPM the respiratory events and hypoxemia resolved but there was persistence of hypoventilation. Tadalafil was initiated for PAH and BPAP therapy for OSA. Follow up visits 4- and 8-weeks post discharge shows improving PAH (TR 3.6 m/sec, eRSVP 52 mmHg, and mild IVSF) due to BPAP and tadalafil therapies. Conclusion This case highlights the importance of treating OSA in patients with PWS to prevent cardiorespiratory complications and reduce morbidity and mortality. Support (if any) None

847 Rapid Improvement of Pulmonary Hypertension with Adequate Ventilatory Support in Patient with Prader-Willi Syndrome

Abstract Introduction Prader-Willi syndrome (PWS) is a genetic multi-system disorder characterized by developmental delay, hyperphagia, and often morbid obesity. Patients can have impairments in ventilatory control and are at risk for sleep disordered breathing due to craniofacial abnormalities, obesity, hypothalamic dysfunction, hypotonia and respiratory muscle weakness. This places them at higher risk for obstructive sleep apnea (OSA), hypoventilation and, if left untreated, may lead to cardiovascular complications. We present a patient with pulmonary hypertension (PH) in the setting of PWS and under supported OSA. Report of case(s) A 17-year-old female with PWS, obesity, type II diabetes mellitus, developmental delay and severe OSA, non-adherent to positive airway pressure (PAP) therapy, presented with 6 months of pedal edema, weight gain with acute shortness of breath, fatigue, and decreased appetite. Upon arrival she developed hypoxemic, hypercapnic respiratory failure requiring intubation. Echocardiogram two months prior to admission showed normal right ventricular size and function with normal septal configuration. Echocardiogram after intubation showed signs of PH with dilated and hypokinetic ventricles compared to prior exam, worsening tricuspid valve regurgitation, and septal bowing. Sleep history was notable for severe OSA in 2017 with obstructive apnea-hypopnea index (oAHI) of 22.6, oxygen nadir of 74%, peak transcutaneous pCO2 of 51 mmHg. Patient was lost to follow-up and as per our history, was non-adherent to PAP therapy. On admission she was started on aggressive diuresis and tadalafil. After successful extubation to BPAP and wean to room air while awake, a BPAP titration PSG was performed. It demonstrated low baseline oxygen saturations (93%), an oxygen nadir of 70%, transcutaneous CO2 peak of 57mmHg with obstructive events eliminated with BPAP of 24/14 cmH20 and hypoxemia treated with 4L supplemental oxygen. With adequate respiratory support with sleep combined with PH monotherapy, repeat echocardiogram prior to discharge showed improved systolic function and only mild septal flattening. Conclusion It is unclear the prevalence of PH in patients with PWS independent of OSA, however it is likely increased overall secondary to the increased prevalence of OSA. As a result, patients with PWS may benefit from routine interval echocardiogram to monitor for signs of PH. Support (if any):

451 Change of sleep disordered breathing severity in obese patients receiving Laparoscopic sleeve gastrectomy

Abstract Introduction Bariatric surgery via laparoscopic sleeve gastrectomy (LSG) was proved to alleviate significantly in apnea hypopnea index (AHI) in obesity patients. We aimed to investigate LSG effects on AHI in different sleep stage (REM vs NREM) and in position (supine vs non-supine) and on CO2 reduction and to identify the factors associated of AHI reduction. Methods From April 2016 to December 2020, 22 obese patients who underwent PSG before and after bariatric surgery at National Taiwan university Hospital were retrospectively studied. The simultaneously nocturnal percutaneous transcutaneous CO2 (PtcCO2) monitoring was applied. Demographic, anthropometric characteristics, Epworth sleepiness scale (ESS), Pittsburgh Sleep Quality Index (PSQI), PSG parameters were reviewed. Responsive to treatment was defined as AHI reduction ≥50% and residual AHI< 10/hour. Results Postoperative PSG was performed in 22 patients [13 men and 9 women, median age 38 years (interquartile range, 32.8–46.5), median body mass index (BMI) 44.5 kg/m2 (39–52.5)] and median follow up days of 535 days (440–687) after LSG. The median post-op BMI was 32.4 kg/m2 (28.3–37.1). The AHI decreased from 51.9/h (27–85.9) to 10.7/h (2–16.3) (p<0.01). The AHINREM decreased from 49.9/h (31.8–91.5) to 5.8/h (1.1–17.3) while the AHIREM decreased from 63.7/h (52.5–83.2) to 19.6/h (4.4–49.7) /h. The AHIsupine decreased from 64.1/h (40.1–88.8) to 11.9/h (2.3–18.7) while the AHInon-supine decreased from 27.5 /h (17.6–78.3) to 1 /h (0–2). The average PtcCO2 decreased from 51.6 mmHg (39.3–54.7) to 46 mmHg (36.6–49.3) while %PtcCO2-total sleep time>50mmHg decreased from 84.5% (0.1–99.1) to 0% (0–44.6). Logistic regression showed baseline higher AHI was independently associated with less treatment responsive [odds ratio, 0.909 (0.84–0.985)]. Conclusion The AHI and PtcCO2 marked decreased via LSG where the residual AHI was lower in NREM than REM sleep; and in non-supine than supine. Baseline AHI is inversely associated with the residual AHI Support (if any) Ministry of Science and Technology (MOST 109-2314-B-002-252)

Association of transcutaneous CO2 with respiratory support: a prospective double blind observational study in children with bronchiolitis and reactive airway disease.

The use of clinical scoring to assess for severity of respiratory distress and respiratory failure is challenging due to subjectivity and interrater variability. Transcutaneous Capnography (TcpCO2) can be used as an objective tool to assess a patient’s ventilatory status. This study was designed to assess for any correlation of continuous monitoring of TcpCO2 with the respiratory clinical scores and deterioration in children admitted for acute respiratory distress. A prospective observational study over one year on children aged 2 weeks to 5 years admitted with acute respiratory distress or failure secondary to Bronchiolitis and Reactive airway disease was performed. Continuous TcpCO2 monitoring for upto 48 h was recorded. Investigators, bedside physicians, respiratory therapists, and nurses were blinded from the transcutaneous trends at the time of data collection. Total of 813 TcpCO2 measurements at standard intervals of 30 min were obtained on 38 subjects. Subjects with abnormal TcpCO2 (> 45 mmHg) were younger (6.9 ± 5.2 vs. 23.05 ± 17.7 months,) and were more likely to be on higher oxygen flow rate (0.52 L/min/kg vs 0.46 lier/min/kg, p = 0.004) and higher FiO2 (38.4 vs 33.6, p < 0.001 using heated high flow nasal cannula. No difference was found in bronchiolitis score or PEW score in subjects with normal and abnormal TcpCO2. A small but statistically significant increase in TcpCO2 was observed at the escalation of care. Even though odds of escalation of care are higher with abnormal TcpCO2 (OR 1.92), this difference did not reach statistical significance. pCO2 can provide additive information for non-invasive clinical monitoring of children requiring varying respiratory support; however, it does not provide predictive value for escalation or de-escalation of care.

Nasal high-flow therapy as an adjunct to exercise in patients with cystic fibrosis: A pilot feasibility trial

BackgroundExercise tolerance in people with CF and advanced lung disease is often reduced. While supplemental oxygen can improve oxygenation, it does not affect dyspnoea, fatigue or comfort. Nasal high-flow therapy (NHFT), thanks to its pathophysiological mechanisms, could improve exercise tolerance, saturation and dyspnoea. This study explores the feasibility of conducting a clinical trial of using NHFT in patients with CF during exercise. MethodsA pilot, open-label, randomized crossover trial was performed, enroling 23 participants with CF and severe lung disease. Participants completed two treadmill walking test (TWT) with and without NHFT at 24–48 h interval. Primary outcome was trial feasibility, and exploratory outcomes were TWT distance (TWTD), SpO2, transcutaneous CO2, dyspnoea and comfort. ResultsRecruitment rate was 2.4 subjects/month with 1.3:1 screening-to-randomization ratio. No adverse events caused by NHFT were observed. Tolerability was good and data completion rate was 100%. Twenty subjects (91%) were included in the exploratory study. Mean difference in TWTD on NHFT was 19 m (95% CI [4.8 - 33.1]). SpO2 was similar, but respiratory rate and mean tcCO2 were lower on NHFT (mean difference = -3.9 breaths/min 95% CI [-5.9 - -1.9] and -0.22 kPa 95% CI [-0.4 – 0.04]). NHFT reduced exercise-induced dyspnoea and discomfort. ConclusionTrials using NHFT in patients with CF during exercise are feasible. NHFT appears to improve walking distance, control respiratory rate, CO2, dyspnoea and improve comfort. A larger trial with a longer intervention is feasible and warranted to confirm the impact of NHFT in training programmes for patients with CF.

Normal values for respiratory sleep polygraphy in children aged 4 to 9 years at 2,560 m above sea level.

Obstructive sleep apnea syndrome affects 1%-4% of all children worldwide. Currently, diagnosis of obstructive sleep apnea is based on sea-level guidelines, without taking into account the altitude at which the populations live. It has been shown that at 3,200 m of altitude there is an increase in obstructive events in healthy children aged 7 to 16years; on the other hand, it is known that SpO2 dispersion between individuals becomes wider as altitude increases, a phenomenon that is more marked during sleep. About 17 million Colombians live in regions between 2,500m and 2,700m, as do significant populations in other Latin American countries. This research aimed to characterize respiratory polygraphy sleep parameters in healthy, non-snoring children aged 4-9years living at 2,560 m. We carried out home respiratory polygraphy in 32 children with a mean age of 6.2years (range 4-9 years). The average recorded sleep time was 7.8h, the median apnea-hypopnea index was 9.2/h, the obstructive apnea-hypopnea index had a median of 8.8/h (p5 4.2 to p95 17.9) and central apnea a median of 0.4/h. The median SpO2 was 93% (p5 90.5 to p95 94) and transcutaneous CO2 had a median of 39.4mmHg (p531.7 to p95 42.3). The median oxygen desaturation index≥3% was 11.2 and median oxygen desaturation index≥4% was 3.9. Normal measurements for respiratory polygraphy obtained at sea level do not apply to children at altitude. If such guidelines are used, obstructive sleep apnea will be over-diagnosed, resulting in unnecessary adenotonsillectomies, among other interventions.

A capnography and transcutaneous CO2 profile of bariatric patients during early postoperative period after opioid-sparing anesthesia.

Noninvasive monitoring of partial pressure of carbon dioxide can be accomplished indirectly with capnography (PETCO2) or with transcutaneous carbon dioxide monitoring (PTCCO2). The use of capnography has been shown to offer an advantage over pulse oximetry alone in the early detection of adverse respiratory events when supplemental oxygen is administered. Furthermore, capnography allows for the monitoring of various respiratory measures, including end-tidal carbon dioxide, respiratory rate, tidal volume, and changes in breathing patterns. Transcutaneous CO2 also closely approximates arterial CO2 values, but is not as easy to monitor for prolonged periods. The purpose of this study was to examine the usefulness of capnography and of transcutaneous carbon dioxide monitoring in patients recovering from obesity surgery at high risk of developing postoperative obstructive sleep apnea. In a prospective observational study, 64 bariatric surgery patients at risk of developing obstructive sleep apnea were monitored in the postanesthesia care unit (PACU) with either capnography alone (31 patients) or capnography plus transcutaneous carbon dioxide monitoring (33 additional patients) every 3-5 minutes for the duration of their recovery. Primary endpoints included end-tidal and transcutaneous carbon dioxide, peripheral oxygen saturation, respiratory rate, pain scores, and incidence of adverse respiratory events. Although no adverse pulmonary events were observed, capnography detected several patients who experienced short periods of respiratory apnea while maintaining pulse oximetry readings within normal limits. Transcutaneous values were slow to change and averaged 4.5 ± 5.5 mm Hg (P< .05) higher than corresponding end-tidal measurements. These results indicate the capabilities of both these noninvasive techniques for postoperative monitoring. Capnography acutely monitors changes in respiration, whereas transcutaneous monitoring more accurately reflects arterial CO2 levels.

Average volume-assured pressure support vs conventional bilevel pressure support in pediatric nocturnal hypoventilation: a case series.

Average volume-assured pressure support (AVAPS) is a modality of noninvasive ventilation that provides a targeted tidal volume by automatically adjusting the inspiratory pressure support within a set range. Pediatric studies evaluating the efficacy of AVAPS in treating nocturnal hypoventilation are confined to case reports. The aim of this study was to compare AVAPS to conventional bilevel positive airway pressure (BPAP) support in improving hypercarbia in a cohort of pediatric patients with nocturnal hypoventilation. Retrospective review of patient records at an established tertiary pediatric sleep laboratory over a 6-year period. Ventilatory and sleep study parameters from AVAPS and conventional BPAP titration studies were compared. AVAPS was used only if hypoventilation was not controlled using conventional BPAP. Inspiratory pressures, tidal volumes, and adherence were downloaded on final titrated ventilatory settings. Comparisons were made using paired t test. A total of 19 patients (11 boys, 8 girls; median age 10.5 years, range 1 to 20 years) were identified. Diagnoses included neuromuscular disease (n = 9), obstructive hypoventilation (n = 5), parenchymal lung disease (n = 4), and congenital central hypoventilation syndrome (n = 2). AVAPS demonstrated significant improvement in peak (P = .009) and mean (P = .001). Transcutaneous CO₂ parameters compared to conventional bilevel. Oxygenation on AVAPS showed positive trend but did not reach statistical significance. AVAPS delivered higher tidal volumes (P = .04) using similar pressures. There was no statistically significant difference in obstructive apnea-hypopnea index, respiratory arousal index, sleep efficiency, and adherence between AVAPS and conventional BPAP. AVAPS was an effective alternative to conventional BPAP in improving hypercarbia in our selective cohort of pediatric patients. Prospective, longitudinal studies are needed to evaluate the benefits of AVAPS feature in the pediatric population.

The effect of transcutaneous CO2 therapy for the forefoot surgery in patients with rheumatoid arthritis

The effect of transcutaneous CO₂ therapy for the forefoot surgery in patients with rheumatoid arthritis

End‐tidal CO2 and transcutaneous CO2: Are we ready to replace arterial CO2 in awake children?

AbstractIntroductionArterial blood gas analysis (ABG) is the gold standard test for carbon dioxide measurement. End‐tidal PCO2 (PetCO2) and transcutaneous PCO2 (PtcCO2) are noninvasive alternative methods.ObjectiveTo examine the use of PetCO2 and PtcCO2 as PaCO2 surrogates in awake children.MethodsA prospective observational study. Consecutive awake children in a stable condition referred to the Sleep Unit of Hospital de Pediatría Dr. J. P. Garrahan with suspected or confirmed sleep‐related respiratory disorders requiring ABG were included. PetCO2 and PtcCO2 were recorded simultaneously during arterial puncture. PetCO2 and PtCO2 values were compared with PaCO2. Correlation coefficient and Bland–Altman analysis were applied. The sample size was calculated considering a mean difference ≤3 mmHg as clinically acceptable.ResultsSixty‐eight sample sets were obtained from 67 patients. The median age was 9.11 years (0.23–18.76). During 94.1% of the procedures patients breathed spontaneously, 30% needed multiple punctures and 92% resulted in pain. Median (IQR) PaCO2 (mmHg) was 36.3 (31.45; 40.90), PetCO2 33.0 (29; 39) and PtcCO2 38.8 (32.95; 43.32). Correlation and agreement for PaCO2/PetCO2 and PaCO2/PtcCO2 was r = .6 and .9, and media of bias = 2.83 (−9.97; 15.64) and −1.88 (−9.01; 5.24), respectively. Hypercapnia (PaCO2 &gt; 45.0 mmHg) was present in 8/68 (11.8%) samples. Sensitivity, specificity, positive predictive value and negative predictive value to detect hypercapnia with PetCO2 was 38%, 98%, 75%, and 92%, respectively, and with PtcCO2, 100%, 90%, 57%, and 100%, respectively.ConclusionPtcCO2 showed better agreement with PaCO2 than PetCO2 but because of the wide dispersion of values, neither method can replace the gold standard. Transcutaneous CO2 might be a good screening tool to detect hypercapnia in awake children.

Transcutaneous application of carbon dioxide improves contractures after immobilization of rat knee joint.

Joint contractures are a major complication following joint immobilization. However, no fully effective treatment has yet been found. Recently, carbon dioxide (CO2) therapy was developed and verified this therapeutic application in various disorders. We aimed to verify the efficacy of transcutaneous CO2 therapy for immobilization-induced joint contracture. Twenty-two Wistar rats were randomly assigned to three groups: caged control, those untreated after joint immobilization, and those treated after joint immobilization. The rats were treated with CO2 for 20 min once a daily either during immobilization, (prevention) or during remobilization after immobilization (treatment). Knee extension motion was measured with a goniometer, and the muscular and articular factors responsible for contractures were calculated. We evaluated muscle fibrosis, fibrosis-related genes (collagen Type 1α1 and TGF-β1) in muscles, synovial intima's length, and fibrosis-related proteins (Type I collagen and TGF-β1) in the joint capsules. CO2 therapy for prevention and treatment improved the knee extension motion. Muscular and articular factors decreased in rats of the treatment group. The muscular fibrosis of treated rats decreased in the treatment group. Although CO2 therapy did not repress the increased expression of collagen Type 1α1, the therapy decreased the expression of TGF-β1 in the treatment group. CO2 therapy for treatment improved the shortening of the synovial membrane after immobilization and decreased the immunolabeling of TGF-β1 in the joint capsules. CO2 therapy may prevent and treat contractures after joint immobilization, and appears to be more effective as a treatment strategy for the deterioration of contractures during remobilization.

Transcutaneous CO2 application accelerates fracture repair in streptozotocin-induced type I diabetic rats

IntroductionDiabetes mellitus (DM) negatively affects fracture repair by inhibiting endochondral ossification, chondrogenesis, callus formation, and angiogenesis. We previously reported that transcutaneous CO2 application accelerates fracture repair by promoting endochondral ossification...

Noninvasive Ventilation in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis is a progressive neurodegenerative disease involving upper and lower motor neurons and has limited treatment options. The weakness progresses to involve the diaphragms, resulting in respiratory failure and death. Home noninvasive ventilation has been shown to improve survival and quality of life, especially in those with intact bulbar function. Once initiated, close monitoring with nocturnal oximetry, remote downloads from the home noninvasive ventilation machine, and measurement of serum bicarbonate should be conducted. Additionally, transcutaneous CO2 monitoring can be considered if available. This article discusses the indications, timing, initiation, and management of noninvasive ventilation in amyotrophic lateral sclerosis.