Significant hypercapnia either in CO(2)-insufflated or air-insufflated colonoscopy under deep sedation

VOLUMETRIC CAPNOGRAPHY FOR RESPIRATORY MONITORING OF PATIENTS DURING ROUTINE COLONOSCOPY WITH ROOM-AIR AND CARBON DIOXIDE INSUFFLATION

BACKGROUND

Capnography and carbon dioxide (CO2) insufflation during gastrointestinal endoscopy under sedation are associated with safety and comfort improvements, respectively. Capnography can provide early detection of apnea and hypoxemia, whereas CO2 insufflation causes lower periprocedural discomfort. This is the first study to report the application of volumetric capnography in colonoscopy.

OBJECTIVE

This study aimed to evaluate the use of volumetric capnography with room air (RA) and CO2 insufflation during routine colonoscopy.

METHODS

In this prospective cohort study, 101 patients who underwent routine colonoscopy under sedation with volumetric capnography monitoring were included. Insufflation with RA was used to distend the intestinal lumen in group 1 (n=51), while group 2 (n=50) used CO2 insufflation. The primary endpoints were episodes of hypoxia, alveolar hypoventilation, and end-tidal CO2 (EtCO2). The secondary endpoints were tidal volume per minute, consumption of sedation medications, and post-procedure pain using the Gloucester modified pain scale.

RESULTS

The number of episodes of hypoxia (SpO2<90%) was similar between the groups: four episodes in Group 1 and two episodes in Group 2. The duration of hypoxia was significantly longer in group 2 (P=0.02). Hypoalveolar ventilation (EtCO2) occurred more frequently in Group 2 than in Group 1 (27 vs 18 episodes, P=0.05). Regarding EtCO2, Group 2 showed higher values in cecal evaluation (28.94±4.68 mmHg vs 26.65±6.12 mmHg, P=0.04). Regarding tidal volume per minute, Group 2 had significantly lower values at the cecal interval compared to Group 1 (2027.53±2818.89 vs 970.88±1840.25 L/min, P=0.009). No episodes of hypercapnia (EtCO2 > 60 mmHg) occurred during the study. There was no difference in the consumption of sedation medications between the groups. Immediately after colonoscopy, Group 2 reported significantly less pain than Group 1 (P=0.05).

CONCLUSION

In our study, volumetric capnography during colonoscopy was feasible and effective for monitoring ventilatory parameters and detecting respiratory complications. CO2 insufflation was safe and associated with less pain immediately after colonoscopy.

Efficacy of high flow nasal oxygenation against hypoxemia in sedated patients receiving gastrointestinal endoscopic procedures: A systematic review and meta-analysis

STUDY OBJECTIVE

To evaluate the impact of high flow nasal oxygenation (HFNO) on the risk of hypoxemia during gastrointestinal endoscopic procedures (GEPs) under sedation.

DESIGN

Meta-analysis of randomized controlled trials.

SETTING

Gastrointestinal endoscopy.

INTERVENTION

HFNO.

PATIENTS

Adults patients undergoing GEPs under sedation.

MEASUREMENTS

The primary outcome was risk of hypoxemia, while the secondary outcomes included risks of severe hypoxemia, hypercapnia, need for jaw thrust or other airway interventions, and procedural interruption as well as procedure time, minimum SpO₂, and level of carbon dioxide (CO₂). Analyses based on age, gender, flow rate, risk status of patients were performed to investigate subgroup effects.

RESULTS

Medline, Google scholar, Cochrane Library, and EMBASE databases were searched from inception to July 2021. Seven randomized controlled trials (RCTs) involving 2998 patients published from 2019 to 2021 were included. All GEPs were performed under propofol sedation. Pooled results revealed significantly lower risks of hypoxemia [relative risk (RR) = 0.31, 95% CI:0.13-0.75; 2998 patients], severe hypoxemia (RR = 0.38, 95% CI:0.2-0.74; 2766 patients), other airway interventions (RR = 0.34, 95% CI:0.22-0.52; 2736 patients), procedural interruption (RR = 0.12, 95% CI:0.02-0.64, 451 patients) and a lower CO₂ level [standard mean difference (MD) = -0.21, 95% CI: -0.4 to -0.03; 458 patients] in HFNO group compared to control group. Subgroup analysis focusing on risk of hypoxemia showed no significant subgroup effects, indicating consistent benefits of HFNO in different clinical settings. There were no difference in minimum SpO₂ (p = 0.06; 262 patients), risk of hypercapnia (p = 0.09; 393 patients), need for jaw thrust (p = 0.28; 2256 patients), and procedure time (p = 0.41, 1004 patients) between the two groups.

CONCLUSION

Our results demonstrated the efficacy of high flow nasal oxygenation for reducing the risk of hypoxemia in patients receiving elective gastrointestinal endoscopic procedures under sedation. Further studies are warranted to verify its cost-effectiveness in the gastrointestinal endoscopy setting.

Study on prevention of hypercapnia by Nasal High Flow in patients with endoscopic submucosal dissection during intravenous anesthesia

BACKGROUND

For relatively invasive upper gastrointestinal endoscopy procedures, such as an endoscopic submucosal dissection (ESD), intravenous anesthesia is routinely used to reduce patient anxiety. However, with the use of intravenous sedation, even at mild to moderate depth of anesthesia, there is always a risk of upper airway obstruction due to a relaxation of the upper airway muscles.With the advent of Nasal High Flow (NHF) devices that allow humidified high flow air through the nasal cavity, can be used as a respiratory management method in the context of anesthesia. AIRVO is commonly used for patients with obstructive sleep apnea and other respiratory disorders. This device uses a mild positive pressure load (several cmH2O) that improves carbon dioxide (CO2) washout and reduces rebreathing to improve respiratory function and therefore is widely used to prevent hypoxemia and hypercapnia.This study aims to maintain upper airway patency by applying NHF with air (AIRVO) as a respiratory management method during intravenous anesthesia for patients undergoing an ESD. In addition, this study investigates whether the use of an NHF device in this context can prevent intraoperative hypercapnia and hypoxemia.

METHODS/DESIGN

This study design employed 2 groups of subjects. Both received intravenous anesthesia while undergoing an ESD, and 1 group also used a concurrent nasal cannula NHF device. Here we examine if the use of an NHF device during intravenous anesthesia can prevent hypoxemia and hypercapnia, which could translate to improved anesthesia management.Efficacy endpoints were assessed using a transcutaneous CO2 monitor. This device measured the changes in CO2 concentration during treatment. Transcutaneous CO2 (PtcCO2) concentrations of 60 mmHg or more (PaCO2 > 55 mmHg) were considered marked hypercapnia. PtcCO2 concentrations of 50 to 60 mmHg or more (equivalent to PaCO2 > 45 mmHg) were considered moderate hypercapnia.Furthermore, the incidence of hypoxemia with a transcutaneous oxygen saturation value of 90% or less, and whether the use of NHF was effective in preventing this adverse clinical event were evaluated.

DISCUSSION

The purpose of this study was to obtain evidence for the utility of NHF as a potential therapeutic device for patients undergoing an ESD under anesthesia, assessed by determining if the incidence rates of hypercapnia and hypoxemia decreased in the NHF device group, compared to the control group that did not use of this device.

TRIAL REGISTRATION

The study was registered the jRCTs 072190022.URL https://jrct.niph.go.jp/en-latest-detail/jRCTs072190022.

Insufflation With Carbon Dioxide During Pediatric Colonoscopy for Control of Postprocedure Pain

GOALS

To determine if carbon dioxide (CO2) insufflation in children would improve postprocedure pain following colonoscopy in children.

BACKGROUND

CO2 insufflation during colonoscopy has been found to reduce postcolonoscopy pain in the adult population, but limited data exist in pediatrics.

MATERIALS AND METHODS

We conducted a prospective study with 40 pediatric patients scheduled for outpatient colonoscopy. Patients were enrolled continuously and were randomized to receive CO2 or air insufflation. Patients and colonoscopists were blinded to insufflation method. End tidal CO2 (EtCO2) was documented throughout the procedure. Abdominal pain was established preprocedure then at 1-, 6-, and 24-hour postprocedure. Subject demographics, indications, colonoscopists' year of training, time to cecum, adverse events, and final diagnoses were recorded.

RESULTS

Twenty patients were randomized to each group. Patients receiving air had a statistically significant increase in pain from baseline at 1- and 6-hours after colonoscopy (P=0.007 and 0.008). This was not seen in the CO2 group (P=0.740 and 0.289). There was an increase in postprocedure pain in the air group compared with CO2 group at the 1-hour mark (P=0.032). EtCO2 increased during the procedure, regardless of insufflation method, but no difference was seen between groups (P=0.822).

CONCLUSIONS

Our results demonstrate that higher levels of pain were reported by patients following air compared with those receiving CO2 insufflation. This is the first study to show CO2 is as safe as air, with no increase in EtCO2 between groups in the pediatric population. CO2 is an effective and safe modality and should be considered for pediatric colonoscopies.

Carbon dioxide insufflation or warm-water infusion for unsedated colonoscopy: A randomized controlled trial in patients with chronic constipation in China

AIMS

The effect of carbon dioxide (CO2) insufflation and warm-water infusion during colonoscopy on patients with chronic constipation remains unknown. We evaluated CO 2 insufflation and warm-water irrigation versus air insufflation in unsedated patients with chronic constipation in China.

PATIENTS AND METHODS

This randomized, single-center, controlled trial enrolled 287 consecutive patients, from January 2014 to January 2015, who underwent colonoscopy for chronic constipation. Patients were randomized to CO2 insufflation, warm-water irrigation and air insufflation colonoscopy insertion phase groups. Pain scores were assessed by the visual analog scale (VAS). The primary outcome was real-time maximum insertion pain, recorded by an unblinded nurse assistant. At discharge, the recalled maximum insertion pain was recorded. Meanwhile, patients were requested to select the VAS at 0, 10, 30, and 60 min after the procedure. In addition, cecal intubation and withdrawal time, total procedure time, and adjunct measures were recorded.

RESULTS

A total of 287 patients were randomized. The correlation between real-time and recalled maximum insertion pain ((Pearson coefficient r = 0.929; P < 0.0001) confirmed internal validation of the primary outcome. The mean real-time maximum pain scores during insertion 2.9 ± 2.1 for CO2, 2.7 ± 1.9 for water achieved a significantly lower pain score compared with air (5.7 ± 2.5) group (air vs CO2 P < 0.001; air vs water P < 0.001). However, no significant pain score differences were found between the patients in the CO2 and water groups (CO2 vs water, P = 0.0535). P values in painless colonoscopy and only discomfort colonoscopy (pain 1-2) were, respectively, 6 (6.4%) and 8 (8.5%) for air; 17 (17.7%) and 29 (30.2%) for CO2; 16 (16.5%) and 31 (31.9%) for water. At 0, 10, 30, and 60 min postprocedure, pain scores showed in the CO2 and water groups had significantly reduced than in air group. Insertion time was significantly different between air (10.6 ± 2.5) and CO2 ( 7.2 ± 1.4) (air vs CO2 P < 0.001), air and water (6.9 ± 1.3) (air vs water P < 0.001). However, CO2 and was not significantly different in cecum-intubated time (CO2 vs water, P = 0.404). CO2 and water group in extubation time were significantly different, respectively, CO2 (7.9 ± 1.1) and water (8.0 ± 1.1) (CO2 vs water, P = 0.707). CO2 or water group required less implementation of adjunct measures and more willingness to repeat the procedure.

CONCLUSIONS

Compared with air, the CO2 or water-aided method reduced real-time maximum pain and cecum-intubated time for chronic constipated patients in unsedated colonoscopy. The CO2 insufflation or warm-water irrigation may be a simple and inexpensive way to reduce discomfort in unsedated patients with constipation. This study demonstrated an advantage of using CO2 insufflation and warm-water irrigation during colonoscopy in unsedated constipated patients in China.

Is the type of insufflation a key issue in gastro-intestinal endoscopy?

Endoscopic procedures continue to play an emerging role in diagnosing and treating upper and lower gastrointestinal (GI) disorders. In particular, the introduction of colonoscopy in bowel cancer screening has underlined its promising role in decreasing the incidence of colorectal cancer and reducing tumour related mortality. To achieve these goals patients need to contemplate endoscopic examinations as painless and fearless procedures. The use of carbon dioxide (CO₂) as an alternative insufflation gas in comparison to air has been considered as an essential key to improving patients' acceptance in undergoing endoscopic procedures. CO₂ is absorbed quickly through the bowel mucosa causing less luminal distension and potentially less abdominal pain. However, its exact role has not been defined completely. In particular, the beneficial use of CO₂ in upper GI endoscopy and in sedated patients is still conflicting. In the present review, we aimed to assess the current evidence for using CO₂ in endoscopy and to evaluate its potential role in the future.