A randomized, controlled trial of transcutaneous carbon dioxide monitoring during ERCP

Examination of stabilization of sedation by Nasal High Flow in patients with endoscopic retrograde cholangiopancreatography during sedation using Dexmedetomidine

INTRODUCTION

Dexmedetomidine is used for the sedation method in the case of endoscopic retrograde cholangiopancreatography (ERCP) for the purpose of relieving patient anxiety. It has been reported that CO2 accumulated during sedation causes an arousal reaction, so how to normalize CO2 during sedation can be improved by administration of the minimum necessary sedative.Nasal High Flow oxygen therapy (NHF) uses a mild positive pressure load that improves carbon dioxide washout and reduces rebreathing to improve respiratory function and therefore is widely used to prevent hypoxemia and hypercapnia. In this study, we will investigate whether the upper airway patency would be maintained and the hypercapnia and hypoxemia during sedation would be prevented, by applying NHF as a respiratory management method to patients undergoing ERCP under sedation.

METHODS/DESIGN

In a randomized comparative study of 2 groups, the NHF device use group and the nasal cannula use group, for adult patients who visited the Nagasaki University Hospital and underwent ERCP examination under sedation. For sedation, Dexmedetomidine will be used in combination with and Midazolam and evaluation by anesthesiologist. In addition, as an analgesic, pethidine hydrochloride was administered intravenously. The total dose of the analgesic pethidine hydrochloride used in combination is used as the primary endpoint. As a secondary evaluation item, the percutaneous CO2 concentration is evaluated with a TCO2 monitor to examine whether it is effective in preventing hypercapnia. Furthermore, we will evaluate the incidence of hypoxemia with a percutaneous oxygen saturation value of 90% or less, and examine whether the use of equipment is effective in preventing the occurrence of hypercapnia and hypoxemia.

DISCUSSION

The purpose of this study was to obtain evidence for the utility of NHF as a potential therapeutic device for patients undergoing an ERCP under sedation, 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.

Respiratory support with nasal high flow without supplemental oxygen in patients undergoing endoscopic retrograde cholangiopancreatography under moderate sedation: a prospective, randomized, single-center clinical trial

BACKGROUND

Nasal high flow (NHF) may reduce hypoxia and hypercapnia during an endoscopic retrograde cholangiopancreatography (ERCP) procedure under sedation. The authors tested a hypothesis that NHF with room air during ERCP may prevent intraoperative hypercapnia and hypoxemia.

METHODS

In the prospective, open-label, single-center, clinical trial, 75 patients undergoing ERCP performed with moderate sedation were randomized to receive NHF with room air (40 to 60 L/min, n = 37) or low-flow O₂ via a nasal cannula (1 to 2 L/min, n = 38) during the procedure. Transcutaneous CO₂, peripheral arterial O₂ saturation, a dose of administered sedative and analgesics were measured.

RESULTS

The primary outcome was the incidence of marked hypercapnia during an ERCP procedure under sedation observed in 1 patient (2.7%) in the NHF group and in 7 patients (18.4%) in the LFO group; statistical significance was found in the risk difference (-15.7%, 95% CI -29.1 - -2.4, p = 0.021) but not in the risk ratio (0.15, 95% CI 0.02 - 1.13, p = 0.066). In secondary outcome analysis, the mean time-weighted total PtcCO₂ was 47.2 mmHg in the NHF group and 48.2 mmHg in the LFO group, with no significant difference (-0.97, 95% CI -3.35 - 1.41, p = 0.421). The duration of hypercapnia did not differ markedly between the two groups either [median (range) in the NHF group: 7 (0 - 99); median (range) in the LFO group: 14.5 (0 - 206); p = 0.313] and the occurrence of hypoxemia during an ERCP procedure under sedation was observed in 3 patients (8.1%) in the NHF group and 2 patients (5.3%) in the LFO group, with no significant difference (p = 0.674).

CONCLUSIONS

Respiratory support by NHF with room air did not reduce marked hypercapnia during ERCP under sedation relative to LFO. There was no significant difference in the occurrence of hypoxemia between the groups that may indicate an improvement of gas exchanges by NHF.

TRIAL REGISTRATION

jRCTs072190021 . The full date of first registration on jRCT: August 26, 2019.

Transcutaneous Carbon Dioxide Monitoring More Accurately Detects Hypercapnia than End-Tidal Carbon Dioxide Monitoring during Non-Intubated Video-Assisted Thoracic Surgery: A Retrospective Cohort Study

Transcutaneous carbon dioxide (PtcCO₂) monitoring is known to be effective at estimating the arterial partial pressure of carbon dioxide (PaCO₂) in patients with sedation-induced respiratory depression. We aimed to investigate the accuracy of PtcCO₂ monitoring to measure PaCO₂ and its sensitivity to detect hypercapnia (PaCO₂ > 60 mmHg) compared to nasal end-tidal carbon dioxide (PetCO₂) monitoring during non-intubated video-assisted thoracoscopic surgery (VATS). This retrospective study included patients undergoing non-intubated VATS from December 2019 to May 2021. Datasets of PetCO₂, PtcCO₂, and PaCO₂ measured simultaneously were extracted from patient records. Overall, 111 datasets of CO₂ monitoring during one-lung ventilation (OLV) were collected from 43 patients. PtcCO₂ had higher sensitivity and predictive power for hypercapnia during OLV than PetCO₂ (84.6% vs. 15.4%, p < 0.001; area under the receiver operating characteristic curve; 0.912 vs. 0.776, p = 0.002). Moreover, PtcCO₂ was more in agreement with PaCO₂ than PetCO₂, indicated by a lower bias (bias ± standard deviation; -1.6 ± 6.5 mmHg vs. 14.3 ± 8.4 mmHg, p < 0.001) and narrower limit of agreement (-14.3-11.2 mmHg vs. -2.2-30.7 mmHg). These results suggest that concurrent PtcCO₂ monitoring allows anesthesiologists to provide safer respiratory management for patients undergoing non-intubated VATS.

A prospective randomized controlled trial of the safety and efficacy of carbon dioxide insufflation compared with room air insufflation during gastric endoscopic submucosal dissection

BACKGROUND AND AIM

Carbon dioxide (CO₂ ) insufflation during gastric endoscopic submucosal dissection (GESD) under sedation can be used instead of room air insufflation. Appropriate monitoring of the partial pressure of CO₂ during GESD is necessary due to the impaired respiration. The aim of this study was to assess the safety and efficacy of CO₂ insufflation during GESD compared with conventional room air insufflation.

METHODS

Patients with a gastric epithelial neoplasm or early gastric cancer were enrolled. A total of 76 consecutive patients were randomly assigned to the CO₂ insufflation group (CO₂ group) or the room air insufflation group (air group). The primary outcome was the mean difference of end-tidal CO₂ (EtCO₂ ) between two groups.

RESULTS

The upper bound of the 95% CI for the mean EtCO₂ difference between the two groups before the procedure and at 15, 30 and 45 min after insufflation met the criteria for noninferiority. In a subgroup analysis of patients 70 years and older, the mean difference of EtCO₂ was not significantly different between two groups. However, the air group received more analgesics than the CO₂ group after the procedure (67.6% vs 35.1%, P = 0.005). In addition, in terms of improvement of abdominal pain or bowel gas after 24 h of GESD, CO₂ group showed better results than air group (both P < 0.05).

CONCLUSIONS

CO₂ insufflation during GESD is as safe as using room air, and patients, including elderly patients, receiving CO₂ achieve more rapid relief of abdominal pain and intra-abdominal residual gas during and after the procedure.

Study on prevention of hypercapnia by nasal high flow in patients undergoing endoscopic retrograde cholangiopancreatography during intravenous anesthesia

BACKGROUND

For relatively invasive upper gastrointestinal endoscopy procedures, such as an endoscopic retrograde cholangiopancreatography (ERCP), and also lower gastrointestinal endoscopy procedures, intravenous anesthesia is routinely used to reduce patient anxiety. However, with the use of intravenous anesthesia, 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 ERCP. 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 ERCP, 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 (TCM). This device measured the changes in CO2 concentration during treatment. Transcutaneous CO2 (PtcCO2) concentrations of 60 mm Hg or more (PaCO2 > 55 mm Hg) were considered marked hypercapnia. PtcCO2 concentrations of 50 to 60 mm Hg or more (equivalent to PaCO2 > 45 mm Hg) 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 ERCP under sedation, 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 this device.

TRIAL REGISTRATION

The study was registered in the jRCTs 072190021.URL https://jrct.niph.go.jp/en-latest-detail/jRCTs072190021.

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.

Left Lower Lung Collapse in a Patient Undergoing Endoscopic Procedure

ASA closed claims from 2000 to 2009 have shown that adverse respiratory events are more common in nonoperating room locations like endoscopy suite than in the operating room (44% v/s 20%). Here, we report a case of lung atelectasis which resulted in hypoxemia in a malnourished patient undergoing endoscopic procedure. It is crucial to identify the high-risk patients and monitor them appropriately in the postoperative phase. Continuous capnometry may offer additional benefit by identifying hypercapnia, hypoventilation at the earliest in the recovery area, thus preventing serious complications.

Supraglottic jet oxygenation and ventilation enhances oxygenation during upper gastrointestinal endoscopy in patients sedated with propofol: a randomized multicentre clinical trial

Background

Hypoventilation is the main reason for hypoxia during upper gastrointestinal endoscopy procedures with sedation. The key to preventing hypoxia is to maintain normal ventilation during the procedure. We introduced supraglottic jet oxygenation and ventilation (SJOV) through a new Wei nasal jet tube (WNJ) to reduce the incidence of hypoxia in patients sedated with propofol during upper gastrointestinal endoscopy procedures.

Methods

In a multicentre, prospective randomized single-blinded study, 1781 outpatients undergoing routine upper gastrointestinal endoscopy who were sedated with propofol by an anaesthetist were randomized into the following three groups: the supplementary oxygen via nasal cannula group [nasal cannula oxygen: O 2 (2 litres min -1 ) was administered via a nasal cannula]; the supplementary oxygen via WNJ group [WNJ oxygen: O 2 (2 litres min -1 ) was administered through a WNJ]; and the SJOV via WNJ group (WNJ SJOV: SJOV was administered via WNJ) at three centres from March 2015 to July 2016. The primary outcome of interest was the incidence of hypoxia (peripheral oxygen saturation of 75-89%). Other adverse events were also recorded.

Results

Supraglottic jet oxygenation and ventilation decreased the incidence of hypoxia from 9 to 3% ( P <0.0001). No severe hypoxia occurred in the WNJ SJOV group, one instance occurred in the WNJ oxygen group, and two instances were observed in the nasal cannula oxygen supply control group. Supraglottic jet oxygenation and ventilation-related minor adverse events increased significantly within 1 min after the procedure but decreased 30 min later.

Conclusions

The use of SJOV during upper gastrointestinal endoscopy for patients who are sedated with propofol reduces the incidence of hypoxia, with minor and tolerable adverse events. Supraglottic jet oxygenation and ventilation has a favourable risk-to-benefit ratio and may improve patient safety.

Clinical trial registration

NCT02436018.

Inadequacy of Pulse Oximetry in the Catheterization Laboratory. An Exploratory Study Monitoring Respiratory Status Using Arterial Blood Gases during Cardiac Catheterization with Conscious Sedation

BACKGROUND

Benzodiazepines and opioids are commonly used for conscious sedation (CS) in cardiac catheterization laboratory (CCL) patients. Both drugs are known to predispose to hypoxemia, apnea and decreased responsiveness to PCO₂, resulting in decreased arterial pH and PO₂, as well as increased PCO₂. We want to determine the effects of CS on arterial blood gas (ABG) in CCL patient, and identify if pulse oximetry monitoring is adequate.

METHODS

We enrolled 18 subjects undergoing elective catheterization. Measurement of ABGs at one-minute intervals was done from the moment of arterial access until case end. The results of ABGs were not available to the clinician who administered sedation. Relationships of pH, PCO₂, PaO₂ and SaO₂ were studied by plotting time series graphs. Significant changes were defined as pH <7.30, SaO₂ < 90, and PCO₂ > 50 mmHg.

RESULTS

No significant change in pH, PCO₂, PaO₂ and SaO₂ was noted in 4/18 (22%) subjects. A significant drop in SaO₂ was noted in 4/18 (22%). A significant change in PCO₂ and/or pH was noted in 10/18 (55%) cases. Among the 16 (16/18) subjects receiving supplemental oxygen, 7 (7/18, 39%) had no drop in SaO₂, but developed respiratory acidosis. At the end of the case, 5/18 (28%) subjects had respiratory acidosis with normal PaO₂.

CONCLUSION

Significant hypercarbia and acidosis occurred frequently in this small study during CS in patients undergoing cardiac catheterization. Relying on pulse oximetry alone especially with patients on supplemental oxygen may lead to failure in detecting respiratory acidosis in a significant number of patients.

Quality Assurance in the Endoscopy Suite: Sedation and Monitoring

Recent development and expansion of endoscopy units has necessitated similar progress in the quality assurance of procedure sedation and monitoring. The large number of endoscopic procedures performed annually underlies the need for standardized quality initiatives focused on mitigating patient risk before, during, and immediately after endoscopic sedation, as well as improving procedure outcomes and patient satisfaction. Specific standards are needed for newer sedation modalities, including propofol administration. This article reviews the current guidelines and literature concerning quality assurance and endoscopic procedure sedation.

Extended Monitoring during Endoscopy

Gastrointestinal endoscopic sedation has improved procedural and patient outcomes but is associated with attendant risks of oversedation and hemodynamic compromise. Therefore, close monitoring during endoscopic procedures using sedation is critical. This monitoring begins with appropriate staff trained in visual assessment of patients and analysis of basic physiologic parameters. It also mandates an array of devices widely used in practice to evaluate hemodynamics, oxygenation, ventilation, and depth of sedation. The authors review the evidence behind monitoring practices and current society recommendations and discuss forthcoming technologies and techniques that are poised to improve noninvasive monitoring of patients under endoscopic sedation.

Capnographic Monitoring in Routine EGD and Colonoscopy With Moderate Sedation: A Prospective, Randomized, Controlled Trial

OBJECTIVES

Regulatory changes requiring the use of capnographic monitoring for endoscopic procedures using moderate sedation have placed financial challenges on ambulatory and hospital endoscopy centers across the United States due to the increased cost of training endoscopy personnel and purchasing both capnography-monitoring devices and specialized sampling ports. To date, there has been no published data supporting the use of capnographic monitoring in adult patients undergoing routine endoscopic procedures with moderate sedation. The aim of this randomized, parallel group assignment trial was to determine whether intervention based on capnographic monitoring improves detection of hypoxemia in patients undergoing routine esophagogastroduodenoscopy (EGD) or colonoscopy with moderate sedation.

METHODS

Healthy patients (ASA Physical Classification (ASAPS) I and II)) scheduled for routine outpatient EGD or colonoscopy under moderate sedation utilizing opioid and benzodiazepine combinations were randomly assigned to a blinded capnography alarm or open capnography alarm group. In both study arms, standard cardiopulmonary monitoring devices were utilized with additional capnographic monitoring. The primary end point was the incidence of hypoxemia defined as a fall in oxygen saturation (SaO2) to <90% for ≥10 s. Secondary outcomes included severe hypoxemia, apnea, disordered respirations, hypotension, bradycardia, and early procedure termination for any cause.

RESULTS

A total of 452 patients were randomized; 218 in the EGD and 234 in the colonoscopy groups; 75 subjects in the EGD group (35.9%) and 114 patients (49.4%) in the colonoscopy group were male, and average body mass index was 27.9 and 29.1 (kg/m(2)), respectively. The blinded and open alarm groups in each study arm were similar in regards to use of opioids and/or benzodiazepines and ASAPS classification. There was no significant difference in rates of hypoxemia between the blinded and open capnography arms for EGD (54.1% vs. 49.5; P=0.5) or colonoscopy (53.8 vs. 52.1%; P=0.79).

CONCLUSIONS

Capnographic monitoring in routine EGD or colonoscopy for ASAPS I and II patients does not reduce the incidence of hypoxemia (ClinicalTrials.gov number, NCT01994785).

Guidelines for sedation in gastroenterological endoscopy

Recently, the need for sedation in gastrointestinal endoscopy has been increasing. However, the National Health Insurance Drug Price list in Japan does not include any drug specifically used for the sedation. Although benzodiazepines are the main medication, their use in cases of gastrointestinal endoscopy has not been approved. This has led the Japan Gastrointestinal Endoscopy Society to develop the first set of guidelines for sedation in gastrointestinal endoscopy on the basis of evidence-based medicine in collaboration with the Japanese Society for Anesthesiologists. The present guidelines comprise 14 statements, five of which were judged to be valid on the highest evidence level and three on the second highest level. The guidelines are not intended to strongly recommend the use of sedation for gastrointestinal endoscopy, but rather to indicate the policy as to the choice of appropriate procedures when such sedation is deemed necessary. In clinical practice, the final decision as to the use of sedation should be made by physicians considering patient willingness and physical condition.

The value of Integrated Pulmonary Index (IPI) monitoring during endoscopies in children

The Integrated Pulmonary Index (IPI) is an algorithm included in commercially available monitors that constitutes a representation of 4 parameters: EtCO2, RR, SpO2 and PR. The IPI index has been validated for adults and children older than 1 year of age. In this study we aimed to study the value of IPI monitoring during pediatric endoscopic procedures. Our data consisted of 124 measurements of 109 patients undergoing different procedures (upper endoscopy 84 patients, colonoscopy 6 patients, both 9 patients). The data was divided into 3 groups based on the drug type used: propofol only, 5 patients (group 1); propofol & midazolam, 89 patients (group 2); propofol, midazolam and Fentanyl, 15 patients (group 3). Patients in group 2 and 3 had significantly higher IPI levels than group 1. Significantly lower IPI values were found between ages 4-6 compared to 7-12 years old. High midazolam dose was associated with lower IPI levels during the procedure. No significant differences were found for propofol doses. Patients who had an anesthetist present had lower IPI levels during the procedure compared to those who did not. No differences were noted between the different procedures. IPI alerted all apnea episodes (58 events, IPI = 1) and hypoxia (26 events, IPI ≤ 3) episodes, whereas pulse oximetry captured only the hypoxia episodes (IPI sensitivity = 1, specificity 0.98, positive predictive value 0.95). Younger patient age, use of propofol alone, higher midazolam doses and presence of anesthetist are all associated with lower IPI levels.

Sedation-related complications in gastrointestinal endoscopy

Defining the risk of procedural sedation for gastrointestinal endoscopic procedures remains a vexing challenge. The definitions as to what constitutes a cardiopulmonary unplanned event are beginning to take focus but the existing literature is an amalgam of various definitions and subjective outcomes, providing a challenge to patient, practitioner, and researcher. Gastrointestinal endoscopy when undertaken by trained personnel after the appropriate preprocedural evaluation and in the right setting is a safe experience. However, significant challenges exist in further quantifying the sedation risks to patients, optimizing physiologic monitoring, and sublimating the pharmacoeconomic and regulatory embroglios that limit the scope of practice and the quality of services delivered to patients.

Recommended sedation and intraprocedural monitoring for gastric endoscopic submucosal dissection

Endoscopic submucosal dissection is associated with a longer treatment time and a higher risk of patient discomfort than conventional procedures. Adequate, safe sedation is therefore essential. Sedation can cause adverse effects such as hypoxemia and hypotension, requiring continuous intraoperative and postoperative monitoring of blood pressure, use of the electrocardiogram, and arterial blood oxygen saturation by pulse oximetry. A physician and a nurse solely responsible for sedating and monitoring the patient should be present during treatment.A combination of benzodiazepines and analgesics are generally used for sedation, but new sedatives such as propofol and dexmedetomidine hydrochloride are expected to be useful agents. Endoscopists should become more familiar with sedatives, analgesics, and emergency procedures in the future.

Administration of additional analgesics can decrease the incidence of paradoxical reactions in patients under benzodiazepine-induced sedation during endoscopic transpapillary procedures: prospective randomized controlled trial

AIM

The aim of the present study was to evaluate the efficacy and safety of giving pentazocine as an analgesic with benzodiazepine during endoscopic retrograde cholangiopancreatography (ERCP).

METHODS

The paradoxical reactions (PR) incidence was evaluated as an indicator of usefulness. Transcutaneous arterial carbon dioxide tension (PtcCO(2) ) was evaluated as an indicator of safety. A total of 160 patients were enrolled. Subjects were randomly divided into two groups; group 1 sedated with midazolam only and group 2 sedated both with midazolam and pentazocine (7.5 mg).

RESULTS

The initial dosage introduced sedation before procedure was significantly higher in group 1. The occurrence rate of PR's in group 1 was significantly higher compared to that in group 2 (P = 0.0108). Although maximum PtcCO(2) observed during sedation did not differ between the two groups (48.7 ± 7.2, 50.3 ± 7.6 mmHg, respectively),maximum PtcCO(2) during the first 15 min after the start of sedation was significantly higher in group 2 than in group 1 (P = 0.0294). In multivariate analysis, procedure duration (odds ratio [OR] = 1.048) and midazolam dose (OR = 1.221) were predictive factors for PR.

CONCLUSION

The administration of pentazocine is significantly reduced the incidence of PR's in patients under midazolam induced sedation during ERCP.

Carbon dioxide accumulation during analgosedated colonoscopy: Comparison of propofol and midazolam

AIM: To characterize the profiles of alveolar hypoventilation during colonoscopies performed under sedoanalgesia with a combination of alfentanil and either midazolam or propofol.

METHODS: Consecutive patients undergoing routine colonoscopy were randomly assigned to sedation with either propofol or midazolam in an open-labeled design using a titration scheme. All patients received 4 μg/kg per body weight alfentanil for analgesia and 3 L of supplemental oxygen. Oxygen saturation (SpO₂) was measured by pulse oximetry (POX), and capnography (PcCO₂) was continuously measured using a combined dedicated sensor at the ear lobe. Instances of apnea resulting in measures such as stimulation of the patient, a chin lift, a mask maneuver, or withholding of sedation were recorded. PcCO₂ values (as a parameter of sedation-induced hypoventilation) were compared between groups at the following distinct time points: baseline, maximal rise, termination of the procedure and 5 min after termination of the procedure. The number of patients in both study groups who regained baseline PcCO₂ values (± 1.5 mmHg) five minutes after the procedure was determined.

RESULTS: A total of 97 patients entered this study. The data from 14 patients were subsequently excluded for clinical procedure-related reasons or for technical problems. Therefore, 83 patients (mean age 62 ± 13 years) were successfully randomized to receive propofol (n = 42) or midazolam (n = 41) for sedation. Most of the patients were classified as American Society of Anesthesiologists (ASA) II [16 (38%) in the midazolam group and 15 (32%) in the propofol group] and ASA III [14 (33%) and 13 (32%) in the midazolam and propofol groups, respectively]. A mean dose of 5 (4-7) mg of IV midazolam and 131 (70-260) mg of IV propofol was used during the procedure in the corresponding study arms. The mean SpO₂ at baseline (%) was 99 ± 1 for the midazolam group and 99 ± 1 for the propofol group. No cases of hypoxemia (SpO₂ < 85%) or apnea were recorded. However, an increase in PcCO₂ that indicated alveolar hypoventilation occurred in both groups after administration of the first drug and was not detected with pulse oximetry alone. The mean interval between the initiation of sedation and the time when the PcCO₂ value increased to more than 2 mmHg was 2.8 ± 1.3 min for midazolam and 2.8 ± 1.1 min for propofol. The mean maximal rise was similar for both drugs: 8.6 ± 3.7 mmHg for midazolam and 7.4 ± 3.2 mmHg for propofol. Five minutes after the end of the procedure, the mean difference from the baseline values was significantly lower for the propofol treatment compared with midazolam (0.9 ± 3.0 mmHg vs 4.3 ± 3.7 mmHg, P = 0.0000169), and significantly more patients in the propofol group had regained their baseline value ± 1.5 mmHg (32 of 41 vs 12 of 42, P = 0.0004).

CONCLUSION: A significantly higher number of patients sedated with propofol had normalized PcCO₂ values five minutes after sedation when compared with patients sedated with midazolam.

Inhibitory effects of carbon dioxide insufflation on pneumoperitoneum and bowel distension after percutaneous endoscopic gastrostomy

AIM: To evaluate the inhibitory effects of carbon dioxide (CO₂) insufflation on pneumoperitoneum and bowel distension after percutaneous endoscopic gastrostomy (PEG).

METHODS: A total of 73 consecutive patients who were undergoing PEG were enrolled in our study. After eliminating 13 patients who fitted our exclusion criteria, 60 patients were randomly assigned to either CO₂ (30 patients) or air insufflation (30 patients) groups. PEG was performed by pull-through technique after three-point fixation of the gastric wall to the abdominal wall using a gastropexy device. Arterial blood gas analysis was performed immediately before and after the procedure. Abdominal X-ray was performed at 10 min and at 24 h after PEG to assess the extent of bowel distension. Abdominal computed tomography was performed at 24 h after the procedure to detect the presence of pneumoperitoneum. The outcomes of PEG for 7 d post-procedure were also investigated.

RESULTS: Among 30 patients each for the air and the CO₂ groups, PEG could not be conducted in 2 patients of the CO₂ group, thus they were excluded. Analyses of the remaining 58 patients showed that the patients’ backgrounds were not significantly different between the two groups. The elevation values of arterial partial pressure of CO₂ in the air group and the CO₂ group were 2.67 mmHg and 3.32 mmHg, respectively (P = 0.408). The evaluation of bowel distension on abdominal X ray revealed a significant decrease of small bowel distension in the CO₂ group compared to the air group (P < 0.001) at 10 min and 24 h after PEG, whereas there was no significant difference in large bowel distension between the two groups. Pneumoperitoneum was observed only in the air group but not in the CO₂ group (P = 0.003). There were no obvious differences in the laboratory data and clinical outcomes after PEG between the two groups.

CONCLUSION: There was no adverse event associated with CO₂ insufflation. CO₂ insufflation is considered to be safer and more comfortable for PEG patients because of the lower incidence of pneumoperitoneum and less distension of the small bowel.

Nurse-administered propofol sedation for gastrointestinal endoscopic procedures: first Nordic results from implementation of a structured training program

INTRODUCTION

Proper training to improve safety of NAPS (nurse-administered propofol sedation) is essential.

OBJECTIVE

To communicate our experience with a training program of NAPS.

MATERIALS AND METHODS

In 2007, a training program was introduced for endoscopists and endoscopy nurses in collaboration with the Department of Anaesthesiology. During a 2.5-year period, eight nurses were trained. Propofol was given as monotherapy. The training program for nurses consisted of a 6-week course including theoretical and practical training whereas the training program for endoscopists consisted of 2.5 h of theory. Patients were selected based on strict criteria including patients in ASA (American Society of Anesthesiologists) group I-III.

RESULTS

2527 patients undergoing 2.656 gastrointestinal endoscopic procedures were included. The patients were ASA group I, II and III in 34.7%, 56% and 9,3%, respectively. Median dose of propofol was 300 mg. No mortality was noted. 119 of 2527 patients developed short lasting hypoxia (4.7%); 61 (2.4%) needed suction; 22 (0.9%) required bag-mask ventilation and 8 (0.3%) procedures had to be discontinued. In 11 patients (0.4%), anesthetic assistance was called due to short lasting desaturation. 34 patients (1.3%) experienced a change in blood pressure greater than 30%.

CONCLUSION

NAPS provided by properly trained nurses according to the present protocol is safe and only associated with a minor risk (short lasting hypoxia 4.7%). National or international structured training programs are at present few or non-existing. The present training program has documented its value and is suggested as the basis for the current development of guidelines.

Pediatric sedation: a global challenge

Pediatric sedation is a challenge which spans all continents and has grown to encompass specialties outside of anesthesia, radiology and emergency medicine. All sedatives are not universally available and local and national regulations often limit the sedation practice to specific agents and those with specific credentials. Some specialties have established certification and credentials for sedation delivery whereas most have not. Some of the relevant sedation guidelines and recommendations of specialty organizations worldwide will be explored. The challenge facing sedation care providers moving forward in the 21st century will be to determine how to apply the local, regional and national guidelines to the individual sedation practices. A greater challenge, perhaps impossible, will be to determine whether the sedation community can come together worldwide to develop standards, guidelines and recommendations for safe sedation practice.

Safe and effective sedation in endoscopic submucosal dissection for early gastric cancer: a randomized comparison between propofol continuous infusion and intermittent midazolam injection

PURPOSE

Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) generally takes longer to perform than conventional endoscopy and usually requires moderate/deep sedation with close surveillance for patient safety. The aim of this study was to compare the safety profiles and recovery scores propofol continuous infusion and intermittent midazolam (MDZ) injection as sedation for ESD.

METHODS

Sixty EGC patients scheduled for ESDs between August and November 2008 were included in this prospective study and randomly divided into a propofol (P-group, 28 patients) and an MDZ (M-group, 32 patients) group using an odd-even system. The P-group received a 0.8 mg/kg induction dose and a 3 mg/kg/h maintenance dose of 1% propofol using an infusion pump. All patients received 15 mg pentazocine at the start of the ESD and at 60-min intervals thereafter. We recorded and analyzed blood pressure, oxygen saturation and heart rate during and following the procedure and evaluated post-anesthetic recovery scores (PARS) and subsequent alertness scores.

RESULTS

The propofol maintenance and total dose amounts were (mean +/- standard deviation) 3.7 +/- 0.6 mg/kg/h and 395 +/- 202 mg, respectively. The mean total dose of MDZ was 10.3 +/- 4.5 mg. There were no cases of de-saturation <90% or hypotension <80 mmHg in either group. Alertness scores 15 and 60 min after the procedures were significantly higher in the P-group (4.9/4.9) than in the M-group (4.6/4.5; p < 0.05). The mean PARS 15 and 30 min after the ESDs were significantly higher in the P-group (9.6/9.9) than in the M-group (8.6/9.2; p < 0.01).

CONCLUSION

Based on our results, the ESDs for EGC performed under sedation using propofol continuous infusion were as safe as those performed using intermittent MDZ injection. Propofol-treated patients had a quicker recovery profile than those treated with MDZ. We therefore recommend the use of continuous propofol sedation for ESD, but sedation guidelines for the use of propofol are necessary.

Safety of carbon dioxide insufflation for upper gastrointestinal tract endoscopic treatment of patients under deep sedation

BACKGROUND

It is well known that carbon dioxide (CO(2)) is absorbed faster in the body than air and also that it is rapidly excreted through respiration. This study aimed to investigate the safety of CO(2) insufflation used for esophageal and gastric endoscopic submucosal dissection (ESD) in patients under deep sedation.

METHODS

Patients with either early gastric or esophageal cancers that could be resected by ESD were enrolled in this study from March 2007 to July 2008 and randomly assigned to undergo ESD procedures with CO(2) insufflation (CO(2) group) or air insufflation (air group). A TOSCA measurement system and TOSCA 500 monitor were used to measure and monitor both transcutaneous partial pressure of CO(2) (PtcCO(2)) and oxygen saturation (SpO(2)).

RESULTS

The study enrolled 89 patients and randomly assigned them to a CO(2) group (45 patients) or an air group (44 patients). The mean CO(2) group versus air group measurements were as follows: PtcCO(2) (49.1 +/- 5.0 vs. 50.1 +/- 5.3 mmHg; nonsignificant difference [NS]), maximum PtcCO(2) (55.1 +/- 6.5 vs. 56.8 +/- 7.0 mmHg; NS), PtcCO(2) elevation (9.1 +/- 5.4 vs. 11.4 +/- 5.6 mmHg; p = 0.054), SpO(2) (99.0 +/- 0.7% vs. 99.0 +/- 1.0%; NS), minimum SpO(2) (96.5 +/- 2.4% vs. 95.4 +/- 3.3%; p = 0.085), and SpO(2) depression (2.4 +/- 2.3% vs. 3.3 +/- 2.9%; NS). The PtcCO(2) and SpO(2) measurements were similar in the two groups, but the CO(2) group was better than the air group in PtcCO(2) elevation and minimum SpO(2).

CONCLUSIONS

The findings demonstrated CO(2) insufflation to be as safe as air insufflation for upper gastrointestinal tract ESDs performed for patients under deep sedation without evidencing any adverse effects.

Assessment of end-tidal carbon dioxide during pediatric and adult sedation for endoscopic procedures

BACKGROUND

Pulse oximetry has become the standard of care during endoscopic procedures, despite the fact that significant alveolar hypoventilation may be undetected.

OBJECTIVE

To study the value of end-tidal carbon dioxide (EtCO(2)) measurement during pediatric and adult endoscopic procedures with the patient under general anesthesia (GA) and conscious sedation (CS).

DESIGN AND SETTINGS

Oridion Microcap hand-held capnography by using Smart Bite Bloc with oxygen (O(2)) delivery were used for the procedures. Microstream nondispersive infrared (IR) spectroscopy is used to measure the concentration of molecules that absorb IR light in CO(2) exhaled by the subject. For each patient, we defined an "event" based on a combination of a >or=20% change (increase or decrease) in EtCO(2), with at least one of the following: O(2) saturation (SPO(2)) <or=90%, a >or=20% change of pulse rate or respiratory rate.

PATIENTS

We studied 57 patients, with an age range of 4 to 62 years. Nineteen patients (33.3%) had CS and 38 (66.6%) had GA.

RESULTS

Twenty patients had no events, 32 had 1 event, and 5 patients had 2 events. The highest observed frequency of an event was noted during upper endoscopy under GA (0.35), followed by upper endoscopy under CS (0.32). Fitted univariate logistic regression models indicated that higher variability in EtCO(2) is associated with a higher probability for an event (P < .0001) and that an increase in age is associated with a lower probability for an event (P < .0001). Significant differences in the frequencies of SPO(2) events were related to the type of procedure (P = .0002; highest estimated probability for upper endoscopy) and GA (P < .0001). Similar conclusions were obtained based on the fitted multivariate model.

CONCLUSIONS

EtCO(2) contributes significantly to the prediction of events during endoscopy. A lower mean of EtCO(2), higher variability of EtCO(2), younger age, GA, and upper endoscopy increase the probability of an event.

The use of carbon dioxide for insufflation during GI endoscopy: a systematic review

BACKGROUND

Insufflation of the lumen is required for visualization during GI endoscopy. Carbon dioxide (CO(2)) has been proposed as an alternative to room air for insufflation.

OBJECTIVES

To assess the safety and efficacy of CO(2) insufflation for endoscopy.

DESIGN

Systematic review that focuses on evidence from randomized controlled trials (RCT).

METHODS

Two investigators independently searched MEDLINE from 1950 to February 13, 2008, to identify all articles that reported the use of CO(2) in a GI endoscopy application. Bibliographies of relevant articles were also hand searched to identify other pertinent reports. Data from RCTs, as well as from nonrandomized studies, were extracted.

RESULTS

Nine RCTs were identified that compared CO(2) and air insufflation for GI endoscopy. Fifteen other nonrandomized studies or reports were also reviewed. In the 8 RCTs in which postprocedural pain was assessed, pain was lower in the CO(2) insufflation group compared with the air group. Two RCTs found decreased flatus in the CO(2) group compared with the air group, and 3 RCTs showed there was decreased bowel distention on abdominal radiography in the CO(2) group compared with the air group. Also, in all 9 RCTs and 6 additional studies in which safety was assessed, there was no CO(2) retention and no adverse pulmonary events related to CO(2) insufflation.

LIMITATIONS

Because of study heterogeneity, meta-analytic techniques could not be used.

CONCLUSIONS

Consistent RCT evidence indicates that CO(2) insufflation is associated with decreased postprocedural pain, flatus, and bowel distention. CO(2) insufflation also appears to be safe in patients without severe underlying pulmonary disease.

Supplemental oxygen compromises the use of pulse oximetry for detection of apnea and hypoventilation during sedation in simulated pediatric patients

OBJECTIVE

The goal was to assess the time to recognition of apnea in a simulated pediatric sedation scenario, with and without supplemental oxygen.

METHODS

A pediatric human patient simulator mannequin was used to simulate apnea in a 6-year-old patient who received sedation for resetting of a fractured leg. Thirty pediatricians participating in a credentialing course for sedation were randomly assigned to 2 groups. Those in group 1 (N = 15) used supplemental oxygen, and those in group 2 (N = 15) did not use supplemental oxygen. A third group (N = 10), consisting of anesthesiology residents (postgraduate years 2 and 3 equivalent), performed the scenario with oxygen supplementation, to ensure validity and reliability of the simulation. The time interval from simulated apnea to bag-mask ventilation was recorded. Oxygen saturation and Paco(2) values were recorded. All recorded variables and measurements were compared between the groups.

RESULTS

The time interval for bag-mask ventilation to occur in group 1 (oxygen supplementation) was significantly longer than that in group 2 (without oxygen supplementation) (173 +/- 130 and 83 +/- 42 seconds, respectively). The time interval for bag-mask ventilation to occur was shorter in group 3 (anesthesiology residents) (24 +/- 6 seconds). Paco(2) reached a higher level in group 1 (75 +/- 26 mmHg), compared with groups 2 and 3 (48 +/- 10 and 42 +/- 3 mmHg, respectively). There was no significant difference between the groups in oxygen saturation values at the time of clinical detection of apnea (93 +/- 5%, 88 +/- 5%, and 94 +/- 7%, respectively).

CONCLUSIONS

Hypoventilation and apnea are detected more quickly when patients undergoing sedation breathe only air. Supplemental oxygen not only does not prevent oxygen desaturation but also delays the recognition of apnea.

A national study of cardiopulmonary unplanned events after GI endoscopy

BACKGROUND

Cardiopulmonary unplanned events (CUE) related to conscious sedation constitute a major proportion of GI endoscopy-associated complications.

OBJECTIVES

Our purpose was to study the incidence of CUE during GI endoscopy and to determine factors that may predict CUE.

DESIGN

Retrospective CORI (Clinical Outcomes Research Initiative) database review.

PATIENTS

Undergoing GI endoscopy under conscious sedation.

MAIN OUTCOME MEASUREMENT

CUE associated with GI endoscopy.

RESULTS

Data on 324,737 unique procedures (EGD, 140,692; colonoscopy, 174,255; ERCP, 6092; and EUS, 3698) performed with the patient under conscious sedation were analyzed. Unplanned events were reported in 1.4% of procedures; 0.9% were associated with CUE. Rates of CUE with EGD, colonoscopy, ERCP, and EUS were 0.6%, 1.1%, 2.1%, and 0.9%, respectively. Multiple logistic regression revealed patient age (odds ratio [OR] 1.02, 95% CI 1.01-1.02) and ASA class were significant predictors of CUE (OR compared with ASA I: ASA II 1.05, 95% CI 0.95-1.16; ASA III 1.8, 95% CI 1.6-2.0, ASA IV 3.2, 95% CI 2.5-4.1, ASA V 7.5; 95% CI 3.2-17.6). Inpatient procedures were associated with higher CUE (OR 1.5, 95% CI 1.3-1.7). Compared with universities, nonuniversity sites (OR 1.2, 95% CI 1.1-1.4) and Veterans Administration Medical Centers (OR 1.4, 95% CI 1.2-1.5) had significantly higher CUE. Use of supplemental oxygen during a procedure was associated with significantly more CUE (OR 1.2, 95% CI 1.1-1.3). Involvement of a trainee with a procedure was also associated with higher CUE (OR 1.3, 95% CI 1.1-1.4).

LIMITATIONS

Retrospective review of data entered voluntarily by endoscopists not trained on CORI data entry.

CONCLUSIONS

During GI endoscopy with conscious sedation, patient's age, higher ASA grade, inpatient status, trainee participation, and routine use of oxygen are associated with a higher incidence of CUE.

Complications of endoscopy

This article focuses on potential complications of standard upper and lower endoscopic procedures. Adverse events associated with endoscopic retrograde cholangiopancreatography, EUS, and certain advanced therapeutic techniques such as mucosal resection are not covered. Rather, the article focuses on the recognition of preprocedure risk factors for various complications and the diagnosis and management for procedure-related adverse events.

Minimizing complications: sedation and monitoring

Serious adverse events are fortunately quite rare for procedural sedation. Current physiologic monitoring recommendations are therefore either based on "softer" outcomes, such as transient hypoxemia, or on expert opinion. Pulse oximetry and supplemental oxygen are recommended for the reduction of hypoxemia. Outcomes-based data for extended monitoring are just starting to emerge, and one of these technologies may become a recommended component of patient monitoring. With data on more than 150,000 patients published in the literature, propofol is the most studied sedative agent for gastrointestinal endoscopy. In this author's opinion, its safety and efficacy have been established.

Risk factors for cardiopulmonary events during propofol-mediated upper endoscopy and colonoscopy

BACKGROUND

Propofol-mediated sedation for endoscopy is popular because of its rapid onset and recovery profile.

AIM

To examine procedure-specific occurrence and risk factors for cardiopulmonary events during propofol-mediated upper endoscopy (EGD) and colonoscopy.

DESIGN

A cohort study using the Clinical Outcomes Research Initiative database was used to determine the frequency of cardiopulmonary events. Clinical Outcomes Research Initiative consisted of 69 practice sites comprising 593 US endoscopists. Multivariate logistic regression analysis used variables, such as age, ASA classification and propofol administration by monitored anaesthesia care or gastroenterologist-administered propofol to determine the risk of cardiopulmonary events.

RESULTS

The overall cardiopulmonary event rate for 5928 EGDs and 11 683 colonoscopies was 11.7/1000 cases. For colonoscopy, ascending ASA classification was associated with an increased risk. Monitored anaesthesia care was associated with a decreased adjusted relative risk (0.5, 95% CI: 0.36-0.72). ASA I and II patients receiving monitored anaesthesia care for EGD exhibited a significantly lower relative risk (ARR 0.29, 95% CI: 0.14-0.64). For subjects with ASA class III or greater, there was no difference in the risk between monitored anaesthesia care and gastroenterologist-administered propofol.

CONCLUSIONS

There are procedure-specific risk factors for cardiopulmonary events during propofol-mediated EGD and colonoscopy. These should be taken into account during future prospective comparative trials.

The sensitivity of room-air pulse oximetry in the detection of hypercapnia

OBJECTIVE

To estimate the sensitivity of room-air pulse oximetry in the detection of moderate hypercapnia.

METHODS

In this retrospective case-control study, charts were reviewed from patients with and without moderate hypercapnia (Pa co 2 >50 mm Hg), as determined by analysis of arterial blood gas samples obtained in the ED. Test characteristics (sensitivity, specificity, and likelihood ratios [LR) for room-air pulse oximetry < or = 96% to detect hypercapnia were calculated, as were confidence intervals.

RESULTS

A total of 349 charts were eligible for abstraction-92 cases and 257 controls. A room-air pulse oximetry reading < or = 96% detected 88 of 92 cases of hypercapnia. Test characteristics were as follows (with 95% confidence interval): sensitivity, 0.96 (0.89-0.99); specificity, 0.39 (0.33-0.45), LR of a room-air pulse oximetry value >96%, 0.1 (0.04-0.3); and LR of a room-air pulse oximetry value < or = 96%, 1.6 (1.4-1.7).

CONCLUSION

Room-air pulse oximetry detects moderate hypercapnia with high sensitivity.

Supplemental oxygen impairs detection of hypoventilation by pulse oximetry

STUDY OBJECTIVE

This two-part study was designed to determine the effect of supplemental oxygen on the detection of hypoventilation, evidenced by a decline in oxygen saturation (Spo(2)) with pulse oximetry.

DESIGN

Phase 1 was a prospective, patient-controlled, clinical trial. Phase 2 was a prospective, randomized, clinical trial.

SETTING

Phase 1 took place in the operating room. Phase 2 took place in the postanesthesia care unit (PACU).

PATIENTS

In phase 1, 45 patients underwent abdominal, gynecologic, urologic, and lower-extremity vascular operations. In phase 2, 288 patients were recovering from anesthesia.

INTERVENTIONS

In phase 1, modeling of deliberate hypoventilation entailed decreasing by 50% the minute ventilation of patients receiving general anesthesia. Patients breathing a fraction of inspired oxygen (Fio(2)) of 0.21 (n = 25) underwent hypoventilation for up to 5 min. Patients with an Fio(2) of 0.25 (n = 10) or 0.30 (n = 10) underwent hypoventilation for 10 min. In phase 2, spontaneously breathing patients were randomized to breathe room air (n = 155) or to receive supplemental oxygen (n = 133) on arrival in the PACU.

MEASUREMENTS AND RESULTS

In phase 1, end-tidal carbon dioxide and Spo(2) were measured during deliberate hypoventilation. A decrease in Spo(2) occurred only in patients who breathed room air. No decline occurred in patients with Fio(2) levels of 0.25 and 0.30. In phase 2, Spo(2) was recorded every min for up to 40 min in the PACU. Arterial desaturation (Spo(2) < 90%) was fourfold higher in patients who breathed room air than in patients who breathed supplemental oxygen (9.0% vs 2.3%, p = 0.02).

CONCLUSION

Hypoventilation can be detected reliably by pulse oximetry only when patients breathe room air. In patients with spontaneous ventilation, supplemental oxygen often masked the ability to detect abnormalities in respiratory function in the PACU. Without the need for capnography and arterial blood gas analysis, pulse oximetry is a useful tool to assess ventilatory abnormalities, but only in the absence of supplemental inspired oxygen.

Capnography Accurately Detects Apnea During Monitored Anesthesia Care

Apnea and airway obstruction are common during monitored anesthesia care (MAC). Because their early detection is essential, we sought to measure the efficacy of capnography as an indicator of apnea during MAC at a variety of oxygen flow rates compared with thoracic impedance. Anesthesia care providers using standard American Society of Anesthesiologists monitors were blinded to capnography and thoracic impedance monitoring. Ten (26%) of the 39 patients studied developed 20 s of apnea; none was detected by the anesthesia provider, but all were detected by capnography and impedance monitoring. There was no difference in detection rates between the two methods. Higher oxygen flow rates decreased the amplitude of the capnograph but did not interfere with apnea detection. This pilot study revealed that apnea of at least 20 s in duration may occur in every fourth patient undergoing MAC. Although these episodes were undetected by the anesthesia provider, they were reliably detected by both capnography and respiratory plethysmography. Monitoring of nasal end-tidal CO(2) is an important way to improve safety in patients undergoing MAC.

Extended/advanced monitoring techniques in gastrointestinal endoscopy

The practice of sedation and analgesia is under increasing scrutiny by numerous regulatory agencies, with the aim of making these procedures safer and reducing the incidence of cardiopulmonary complications during GI endoscopy. As we move toward more evidence-based medicine, new technologies will have to be assessed in a manner that demonstrates their efficacy and utility in clinical practice. Although there have been no controlled studies examining whether more intensive monitoring during endoscopy improves outcomes, extended monitoring with capnography seems to offer an advantage over conventional monitoring in that, by providing a real-time indication of any change in adequate ventilation before oxygen desaturation occurs, it can detect early phases of respiratory depression, which can allow a more precise and safer titration of medications. There is a close agreement among experts that capnography may reduce the risk of adverse outcomes during deep sedation; therefore, its use should be required for patients undergoing advanced endoscopic procedures with the potential for deep sedation. Extended monitoring with capnography should also be endorsed whenever propofol is considered as an alternative to standard sedation with a benzodiazepine or narcotic. Our understanding of the clinical application of techniques for monitoring of depth of sedation is in its infancy, and its full contribution to the practice of endoscopy has yet to be determined. Their potential role in improving sedation practice during endoscopy needs to be confirmed by controlled trials. If we consider the lack of proven efficacy of these emerging monitoring techniques in reducing the adverse outcomes associated with sedation and analgesia, the importance of appropriate monitoring cannot be overemphasized. However, it is vital for the endoscopist to be thoroughly familiar with the type of sedation chosen, to be able to recognize the various levels of sedation, and, above all, to rescue patients should they unintentionally progress to a deeper level of sedation than intended.

Propofol: a gastroenterologist's perspective

The use of propofol for GI endoscopy has left the realm of experimentation and is now a viable alternative to standard sedation and analgesia. In the hands of appropriately trained gastroenterologists and registered nurses, propofol has been shown to be superior to standard sedation and analgesia in terms of patient satisfaction and comfort and shorter recovery parameters. Comparative studies have found it to be as safe as the regimens that are used for standard sedation and analgesia. Its narrow therapeutic window demands that specially trained personnel who are not directly involved in the endoscopic procedure administer it. Cost-effectiveness data suggest that propofol is superior to conventional sedation and analgesia, even with the use of added personnel.The importance of pre-procedural assessment and appropriate monitoring cannot be overemphasized. The endoscopist must have a thorough knowledge of the pharmacology of the agents used for sedation and the training necessary to recognize and manage over sedation. Numerous regulatory groups are carefully scrutinizing the practice of sedation and analgesia. It seems that ventilatory monitoring will be required for at least a subset of patients. Although hypercapnia and apnea can be reliably measured, the most important questions to be answered are if such monitoring affects patient outcomes and which patients are at risk for apnea and alveolar hypoventilation.

Guidelines for conscious sedation and monitoring during gastrointestinal endoscopy

This is one of a series of statements discussing the utilization of GI endoscopy in common clinical situations. The Standards of Practice Committee of the American Society for Gastrointestinal Endoscopy prepared this text. In preparing this guideline, a MEDLINE literature search was performed, and additional references were obtained from the bibliographies of the identified articles and from recommendations of expert consultants. When little or no data exist from well-designed prospective trials, emphasis is given to results from large series and reports from recognized experts. Guidelines for appropriate utilization of endoscopy are based on a critical review of the available data and expert consensus. Further controlled clinical studies are needed to clarify aspects of this statement, and revision may be necessary as new data appear. Clinical consideration may justify a course of action at variance to these recommendations.

Safety of propofol for conscious sedation during endoscopic procedures in high-risk patients-a prospective, controlled study

OBJECTIVES

Propofol, a rapidly-acting hypnotic agent, is increasingly being used for endoscopic sedation. Serious adverse effects, including respiratory and cardiovascular depression, make many endoscopists reluctant to use propofol in critically ill patients. This study characterizes propofol's safety profile in consecutive high-risk patients (American Society of Anesthesiologists [ASA] classes III and IV) compared with matched subjects (ASA classes I and II).

METHODS

During a 19-month period, 1370 at risk-patients were sedated with propofol, of whom 47% (614 ASA III, 28 ASA IV) were age matched with 642 consecutive patients of the same gender and age assigned to ASA classes I and II and undergoing the same endoscopic procedures (395 gastroscopies, 201 colonoscopies, 14 combined). Registered nurses performed all sedations by propofol dose titration while carefully monitoring arterial oxygen saturation, heart rate, and blood pressure.

RESULTS

No major complications occurred among the critically ill patients. There was, however, an increased risk for a short relevant oxygen desaturation (<90%) of 3.6% for ASA III and IV versus 1.7% for ASA I and II (p = 0.036). In four versus one case, short mask ventilation was necessary. Also, a greater proportion of patients showed a > or =5% oxygen saturation decrease. There was no pronounced influence on arterial pressure or heart rate and no perforations in 336 colonoscopies.

CONCLUSIONS

With careful monitoring, propofol sedation during GI endoscopies is safe, even for high-risk patients. Considering their higher comorbidity and tendency toward oxygen desaturation, they need particularly careful monitoring, and the required dose is, on mean, 10-20% lower than in ASA classes I and II.

Laryngeal mask airway--a novel method of airway protection during ERCP: comparison with endotracheal intubation

BACKGROUND

ERCP sometimes requires deep sedation and rarely general anesthesia with airway protection. The laryngeal mask airway device is placed perorally to create a seal over the larynx. Unlike endotracheal intubation, no tube traverses the vocal cords, thus reducing airway stimulation and obviating the need to administer muscle relaxants. The feasibility of using the laryngeal mask airway during ERCP was evaluated and recovery times compared for patients undergoing ERCP with the laryngeal mask airway versus endotracheal intubation.

METHODS

In this retrospective cohort study, anesthesia records were reviewed for anesthesiologist-assisted ERCP procedures performed during a 30-month period. Demographics, procedure duration, and time from endoscope removal to extubation were abstracted. Either propofol or inhalation agents were used for anesthesia in all patients.

OBSERVATIONS

Anesthesiologists administered sedation for 41 ERCPs. The airway was managed in 12 patients with endotracheal intubation and the laryngeal mask airway in 20 patients. Six patients underwent laryngeal mask airway insertion and removal while prone. A therapeutic duodenoscope was passed beyond the laryngeal mask airway with little or no resistance in all cases. Repositioning the laryngeal mask airway during the procedure was required in 1 case. Laryngeal mask airway use was associated with shorter extubation time compared with endotracheal intubation (7.2 vs. 12 min.; p = 0.004). There were no airway complications.

CONCLUSION

ERCP can be performed while using the laryngeal mask airway for airway protection. The laryngeal mask airway can be placed with the patient prone, obviating the need to change position. Laryngeal mask airway shortens extubation time compared with endotracheal intubation.

Automated graphic assessment of respiratory activity is superior to pulse oximetry and visual assessment for the detection of early respiratory depression during therapeutic upper endoscopy

BACKGROUND

Recommendations from the American Society of Anesthesiologists suggest that monitoring for apnea using the detection of exhaled carbon dioxide (capnography) is a useful adjunct in the assessment of ventilatory status of patients undergoing sedation and analgesia. There are no data on the utility of capnography in GI endoscopy, nor is the frequency of abnormal ventilatory activity during endoscopy known. The aims of this study were to determine the following: (1) the frequency of abnormal ventilatory activity during therapeutic upper endoscopy, (2) the sensitivity of observation and pulse oximetry in the detection of apnea or disordered respiration, and (3) whether capnography provides an improvement over accepted monitoring techniques.

METHODS

Forty-nine patients undergoing therapeutic upper endoscopy were monitored with standard methods including pulse oximetry, automated blood pressure measurement, and visual assessment. In addition, graphic assessment of respiratory activity with sidestream capnography was performed in all patients. Endoscopy personnel were blinded to capnography data. Episodes of apnea or disordered respiration detected by capnography were documented and compared with the occurrence of hypoxemia, hypercapnea, hypotension, and the recognition of abnormal respiratory activity by endoscopy personnel.

RESULTS

Comparison of simultaneous respiratory rate measurements obtained by capnography and by auscultation with a pretracheal stethoscope verified that capnography was an excellent indicator of respiratory rate when compared with the reference standard (auscultation) (r = 0.967, p < 0.001). Fifty-four episodes of apnea or disordered respiration occurred in 28 patients (mean duration 70.8 seconds). Only 50% of apnea or disordered respiration episodes were eventually detected by pulse oximetry. None were detected by visual assessment (p < 0.0010).

CONCLUSIONS

Apnea/disordered respiration occurs commonly during therapeutic upper endoscopy and frequently precedes the development of hypoxemia. Potentially important abnormalities in respiratory activity are undetected with pulse oximetry and visual assessment.