Mechanisms of hypoxemia during panendoscopy

Phase II study comparing nasal pressure monitoring with capnography during invasive endoscopic procedures: a single-center, single-arm trial

Nasal pressure signal is commonly used to evaluate obstructive sleep apnea. This study aimed to assess its safety for respiratory monitoring during sedation. A total of 45 adult patients undergoing sedation with propofol and fentanyl for invasive endoscopic procedures were enrolled. While both nasal pressure and capnograph signals were continuously recorded, only the nasal pressure signal was displayed. The primary outcome was the incidence of oxygen desaturation below 90%. The secondary outcomes were the ability to predict the desaturation and incidence of harmful events and false alarms, defined as an apnea waveform lasting more than 3 min without desaturation. Of the 45 participants, 43 completed the study. At least one desaturation event occurred in 12 patients (27.9%; 95% confidence interval 15.3-43.7%). In these 12 patients, more than half of the desaturation events were predictable in 9 patients by capnography and 11 patients by nasal pressure monitoring (p = 0.59). In the 43 patients, false alarms were detected in 7 patients with capnography and 11 patients with nasal pressure monitoring (p = 0.427). Harmful events unrelated to nasal pressure monitoring occurred in 2 patients. Nasal pressure monitoring is safe and possibly useful for respiratory monitoring despite false alarms during sedation.

Effect of remimazolam tosilate on the incidence of hypoxemia in elderly patients undergoing gastrointestinal endoscopy: A bi-center, prospective, randomized controlled study

Background: Remimazolam tosilate is a new ultra-short-acting benzodiazepine sedative medicine. In this study, we evaluated the effect of remimazolam tosilate on the incidence of hypoxemia during sedation in elderly patients undergoing gastrointestinal endoscopy. Methods: Patients in the remimazolam group received an initial dose of 0.1 mg/kg and a bolus dose of 2.5 mg of remimazolam tosilate, whereas patients in the propofol group received an initial dose of 1.5 mg/kg and a bolus dose of 0.5 mg/kg of propofol. Patients received ASA standard monitoring (heart-rate, non-invasive blood pressure, and pulse oxygen saturation) during the entire examination process. The primary outcome was the incidence of moderate hypoxemia (defined as 85%≤ SpO₂< 90%, >15s) during the gastrointestinal endoscopy. The secondary outcomes included the incidence of mild hypoxemia (defined as SpO₂ 90%-94%) and severe hypoxemia (defined as SpO₂< 85%, >15s), the lowest pulse oxygen saturation, airway maneuvers used to correct hypoxemia, patient's hemodynamic as well as other adverse events. Results: 107 elderly patients (67.6 ± 5.7 years old) in the remimazolam group and 109 elderly patients (67.5 ± 4.9 years old) in the propofol group were analyzed. The incidence of moderate hypoxemia was 2.8% in the remimazolam group and 17.4% in the propofol group (relative risk [RR] = 0.161; 95% confidence interval [CI], 0.049 to 0.528; p < 0.001). The frequency of mild hypoxemia was less in the remimazolam group, but not statistically significant (9.3% vs. 14.7%; RR = 0.637; 95% CI, 0.303 to 1.339; p = 0.228). There was no significant difference in the incidence of severe hypoxemia between the two groups (4.7% vs. 5.5%; RR = 0.849; 95% CI, 0.267 to 2.698; p = 0.781). The median lowest SpO₂ during the examination was 98% (IQR, 96.0%-99.0%) in patients in the remimazolam group, which was significantly higher than in patients in the propofol group (96%, IQR, 92.0%-99.0%, p < 0.001). Patients in the remimazolam group received more drug supplementation during endoscopy than patients in the propofol group (p = 0.014). There was a statistically significant difference in the incidence of hypotension between the two groups (2.8% vs. 12.8%; RR = 0.218; 95% CI, 0.065 to 0.738; p = 0.006). No significant differences were found in the incidence of adverse events such as nausea and vomiting, dizziness, and prolonged sedation. Conclusion: This study explored the safety of remimazolam compared with propofol during gastrointestinal endoscopy in elderly patients. Despite the increased supplemental doses during sedation, remimazolam improved risk of moderate hypoxemia (i.e., 85%≤ SpO₂ < 90%) and hypotension in elderly patients.

Evaluation of the Integrated Pulmonary Index® during non-anesthesiologist sedation for percutaneous endoscopic gastrostomy

Standard monitoring of heart rate, blood pressure and arterial oxygen saturation during endoscopy is recommended by current guidelines on procedural sedation. A number of studies indicated a reduction of hypoxic (art. oxygenation < 90% for > 15 s) and severe hypoxic events (art. oxygenation < 85%) by additional use of capnography. Therefore, U.S. and the European guidelines comment that additional capnography monitoring can be considered in long or deep sedation. Integrated Pulmonary Index® (IPI) is an algorithm-based monitoring parameter that combines oxygenation measured by pulse oximetry (art. oxygenation, heart rate) and ventilation measured by capnography (respiratory rate, apnea > 10 s, partial pressure of end-tidal carbon dioxide [PetCO2]). The aim of this paper was to analyze the value of IPI as parameter to monitor the respiratory status in patients receiving propofol sedation during PEG-procedure. Patients reporting for PEG-placement under sedation were randomized 1:1 in either standard monitoring group (SM) or capnography monitoring group including IPI (IM). Heart rate, blood pressure and arterial oxygen saturation were monitored in SM. In IM additional monitoring was performed measuring PetCO2, respiratory rate and IPI. Capnography and IPI values were recorded for all patients but were only visible to the endoscopic team for the IM-group. IPI values range between 1 and 10 (10 = normal; 8-9 = within normal range; 7 = close to normal range, requires attention; 5-6 = requires attention and may require intervention; 3-4 = requires intervention; 1-2 requires immediate intervention). Results on capnography versus standard monitoring of the same study population was published previously. A total of 147 patients (74 in SM and 73 in IM) were included in the present study. Hypoxic events occurred in 62 patients (42%) and severe hypoxic events in 44 patients (29%), respectively. Baseline characteristics were equally distributed in both groups. IPI = 1, IPI < 7 as well as the parameters PetCO2 = 0 mmHg and apnea > 10 s had a high sensitivity for hypoxic and severe hypoxic events, respectively (IPI = 1: 81%/81% [hypoxic/severe hypoxic event], IPI < 7: 82%/88%, PetCO2: 69%/68%, apnea > 10 s: 84%/84%). All four parameters had a low specificity for both hypoxic and severe hypoxic events (IPI = 1: 13%/12%, IPI < 7: 7%/7%, PetCO2: 29%/27%, apnea > 10 s: 7%/7%). In multivariate analysis, only SM and PetCO2 = 0 mmHg were independent risk factors for hypoxia. IPI (IPI = 1 and IPI < 7) as well as the individual parameters PetCO2 = 0 mmHg and apnea > 10 s allow a fast and convenient conclusion on patients' respiratory status in a morbid patient population. Sensitivity is good for most parameters, but specificity is poor. In conclusion, IPI can be a useful metric to assess respiratory status during propofol-sedation in PEG-placement. However, IPI was not superior to PetCO2 and apnea > 10 s.

High-Flow Nasal Cannula and Mandibular Advancement Bite Block Decrease Hypoxic Events during Sedative Esophagogastroduodenoscopy: A Randomized Clinical Trial

During sedated endoscopic examinations, upper airway obstruction occurs. Nasal breathing often shifts to oral breathing during open mouth esophagogastroduodenoscopy (EGD). High-flow nasal cannula (HFNC) which delivers humidified 100% oxygen at 30 L min⁻¹ may prevent hypoxemia. A mandibular advancement (MA) bite block with oxygen inlet directed to both mouth and nose may prevent airway obstruction during sedated EGD. The purpose of this study was to evaluate the efficacy of these airway devices versus standard management. One hundred and eighty-nine patients were assessed for eligibility. One hundred and fifty-three were enrolled. This study randomly assigned eligible patients to three arms: the standard bite block and standard nasal cannula, HFNC, and MA bite block groups. EGD was performed after anaesthetic induction. The primary endpoint was the oxygen desaturation area under curve at 90% (AUC_Desat). The secondary endpoints were percentage of patients with hypoxic, upper airway obstruction, and apnoeic and rescue events. One hundred and fifty-three patients were enrolled. AUCdesat was significantly lower for HFNC and MA bite blocks versus the standard management (p= 0.019). The HFNC reduced hypoxic events by 18% despite similar airway obstruction and apnoeic events as standard group. The MA bite block reduced hypoxic events by 12% and airway obstructions by 32%. The HFNC and MA groups both showed a 16% and 14% reduction in the number of patients who received rescue intervention, respectively, compared to the standard group. The HFNC and MA bite block may both reduce degree and duration of hypoxemia. HFNC may decrease hypoxemic events while maintaining nasal patency is crucial during sedative EGD. The MA bite block may prevent airway obstruction and decrease the need for rescue intervention.

Clinical application of a novel endoscopic mask: A randomized controlled trial in aged patients undergoing painless gastroscopy

Background: Desaturation during painless gastroscopy in aged patients leads to discontinuation of the procedure, prolonged manipulation time and increased risk of severe complications. An endoscopic nasal mask was designed to control hypoxia during the above procedures. A randomized trial was performed to test whether the novel endoscopic mask is helpful for hypoxia during painless gastroscopy in aged patients. Methods: In this randomized, controlled trial, 141 aged patients undergoing painless gastroscopy were randomized into nasal catheter group (69 patients) and endoscopic mask group (65 patients). Primary outcomes were minimum pulse oxygen saturation and incidence of pulse oxygen saturation ≤ 90%. Results: Finally, 134 aged patients were analyzed, including 69 patients in nasal catheter group and 65 patients endoscopic mask group. The minimum pulse oxygen saturation (96.4% ± 4.8%) was higher in the aged endoscopic mask group than in the aged nasal catheter group (94.3% ± 5.6%, P = 0.0075). The incidence of pulse oxygen saturation ≤ 90% did not significantly differ between the endoscopic mask group and nasal catheter group (6.2% VS 15.9%, P = 0.07). There were no severe adverse events in either groups. Conclusion: The endoscopic mask was safely used in aged patients during painless gastroscopy under propofol sedation and significantly improved the minimum pulse oxygen saturation without increasing time to examination or recovery time.

Risk of sedation for diagnostic esophagogastroduodenoscopy in obstructive sleep apnea patients

AIM

To investigate whether patients with obstructive sleep apnea (OSA) are at risk of sedation-related complications during diagnostic esophagogastroduodenoscopy (EGD).

METHODS

A prospective study was performed in consecutive patients with OSA, who were confirmed with full-night polysomnography between July 2010 and April 2011. The occurrence of cardiopulmonary complications related to sedation during diagnostic EGD was compared between OSA and control groups.

RESULTS

During the study period, 31 patients with OSA and 65 controls were enrolled. Compared with the control group, a higher dosage of midazolam was administered (P = 0.000) and a higher proportion of deep sedation was performed (P = 0.024) in the OSA group. However, all adverse events, including sedation failure, paradoxical responses, snoring or apnea, hypoxia, hypotension, oxygen or flumazenil administration, and other adverse events were not different between the two groups (all P > 0.1). Patients with OSA were not predisposed to hypoxia with multivariate logistic regression analysis (P = 0.068).

CONCLUSION

In patients with OSA, this limited sized study did not disclose an increased risk of cardiopulmonary complications during diagnostic EGD under sedation.

Classification of patients who experience a higher distress level to transoral esophagogastroduodenoscopy than to transnasal esophagogastroduodenoscopy

BACKGROUND

In Japanese routine clinical practice, endoscopy is generally carried out without sedation. The present study aimed to identify the factors essential for appropriate selection of transnasal esophagogastroduodenoscopy (TN-EGD) as an alternative to unsedated transoral esophagogastroduodenoscopy (TO-EGD).

PATIENTS AND METHODS

Subjects in this prospective cohort study comprised consecutive outpatients who underwent EGD at a single center. Factors predicting TO-EGD-induced distress were evaluated on a visual analog scale (VAS) and analyzed. Patients were classified into a two-layered system on the basis of these predictive factors, and the severity of distress between the TN-EGD and TO-EGD groups was compared using VAS and the change in the rate-pressure product as subjective and objective indices, respectively.

RESULTS

In total, 728 outpatients (390 male, 338 female; mean age, 63.1 ± 0.5 years; TO-EGD group, 630; TN-EGD group, 98)met the inclusion criteria. Multivariate logistic regression analysis confirmed that age <65 years (P < 0.01; odds ratio [OR], 1.69; 95% confidence interval [CI], 1.14-2.52), gender (female; P < 0.01; OR,1.97; 95% CI, 1.34-2.91), marital status (single; P < 0.01; OR, 1.96; 95% CI, 1.18-3.27), and anxiety towards TO-EGD (P < 0.001; OR, 3.62; 95% CI, 2.44-5.37) were independently associated with intolerance. Both indices were significantly higher in the TO-EGD subgroup than in the TN-EGD subgroup in the high predictive class, but not in the low predictive class.

CONCLUSION

Predictive factors for detecting intolerance to unsedated TO-EGD may be useful to appropriately select patients who transpose unsedated TO-EGD to TN-EGD.

Compromised ventilation caused by tracheoesophageal fistula and gastrointestinal endoscope undergoing removal of disk battery on esophagus in pediatric patient -A case report-

Ingestion of disk batteries may have serious complications such as esophageal burn, perforation, and tracheoesophageal fistula, particularly when the battery is caught in the esophagus. Proper placement of the tracheal tube is critical when tracheoesophageal fistula was occurred from esophageal impaction the battery. Endoscopy of upper gastrointestinal tract in infants and children is an important and effective tool for the diagnosis and treatment of foreign body ingestion. But upper gastrointestinal endoscopy in infant and children has very high risk of tracheal compression and airway compromise. We present a case of ventilatory compromise during insertion of the upper gastrointestinal endoscopy in 16-month-old child with tracheoesophageal fistula secondary to disk battery ingestion.

Sub-clinical hepatic encephalopathy in cirrhotic patients is not aggravated by sedation with propofol compared to midazolam: a randomized controlled study

BACKGROUND & AIMS

The risk of exacerbating sub-clinical hepatic encephalopathy (HE) by propofol has not been established. The aim of this study is to determine whether the use of propofol, for upper endoscopy in patients with cirrhosis, precipitates sub-clinical HE.

METHODS

Sixty-one patients with compensated HCV and HBV cirrhosis (CP score 5-6) were randomly selected and divided into two groups (intent-to-treat population) matched for age, gender, and BMI. The first group received a single propofol sedation (N = 31, age 57 ± 12, dose range 70-100 mg/procedure) and the second group (N = 30, age 56 ± 12, dose 3-6 mg/procedure) received a single midazolam sedation, all done by an anesthesiologist. All patients completed number connection test (NCT), cognitive function score, time to recovery, time to discharge sheets, and hemodynamic parameters before sedation, and at discharge from the endoscopy unit, 1h post-procedure. Thirty control subjects without cirrhosis were matched to the cirrhotic patients who received sedation with regard to age, gender, BMI, and education level.

RESULTS

A total of 58/61 cirrhotic patients (95%) had sub-clinical encephalopathy before the endoscopy (mean NCT 84.7 ± 77 s, normal < 30 s). No patient developed overt HE after sedation. There were no differences between groups in the incidence of adverse effects, cognitive function, MELD score, CP score, oxygen saturation, or respiratory and heart rates before and after sedation. Propofol did not exacerbate minimal HE when compared to midazolam (NCT changed from 87.5 ± 62 s prior to sedation to 74.2 ± 58 s after sedation in the propofol group versus 72.8 ± 62 s before to 85.6 ± 72 s after sedation in the midazolam group; p < 0.01). Time to recovery (4.1 ± 1.9 min vs. 11.5 ± 5.0 min, p < 0.001), and time to discharge (38.0 ± 9 min vs. 110 ± 42 min, p < 0.001) were significantly shorter with propofol than midazolam. Pre- and post-procedure NCT (from 25 ± 20 s to 24 ± 20 s), cognitive function score (from 25 to 26), time to recovery (3.5 ± 1.0 min), and time to discharge (35 ± 10 min) did not change in the healthy controls.

CONCLUSIONS

Sedation with propofol has a shorter time recovery and a shorter time to discharge than midazolam and does not exacerbate sub-clinical hepatic encephalopathy in patients with compensated liver cirrhosis.

Randomized controlled trial of patient-controlled sedation for colonoscopy: Entonox vs modified patient-maintained target-controlled propofol

AIM

Propofol sedation is often associated with deep sedation and decreased manoeuvrability. Patient-maintained sedation has been used in such patients with minimal side-effects. We aimed to compare novel modified patient-maintained target-controlled infusion (TCI) of propofol with patient-controlled Entonox inhalation for colonoscopy in terms of analgesic efficacy (primary outcome), depth of sedation, manoeuvrability and patient and endoscopist satisfaction (secondary outcomes).

METHOD

One hundred patients undergoing elective colonoscopy were randomized to receive either TCI propofol or Entonox. Patients in the propofol group were administered propofol initially to achieve a target concentration of 1.2 μg/ml and then allowed to self-administer a bolus of propofol (200 μg/kg/ml) using a patient-controlled analgesia pump with a handset. Entonox group patients inhaled the gas through a mouthpiece until caecum was reached and then as required. Sedation was initially given by an anaesthetist to achieve a score of 4 (Modified Observer's Assessment of Alertness and Sedation Scale), and colonoscopy was then started. Patients completed an anxiety score (Hospital Anxiety and Depression questionnaire), a baseline letter cancellation test and a pain score on a 100-mm visual analogue scale before and after the procedure. All patients completed a satisfaction survey at discharge and 24 h postprocedure.

RESULTS

The median dose of propofol was 174 mg, and the median number of propofol boluses was four. There was no difference between the two groups in terms of pain recorded (95% confidence interval of the difference -0.809, 5.02) and patient/endoscopist satisfaction. There was no difference between the two groups in either depth of sedation or manoeuvrability.

CONCLUSION

Both Entonox and the modified TCI propofol provide equally effective sedation and pain relief, simultaneously allowing patients to be easily manoeuvred during the procedures.

Flexible upper videoendoscopy through a modified endoscopy mask in infants and young children

Esophagogastroduodenoscopy (EGD) is considered an essential diagnostic and therapeutic procedure in the pediatric population. Although generally safe, EGD has the potential for airway complications. We routinely use general anesthesia to carry out EGD in patients younger than 10 years. In the past, these patients received oxygen either through a nasal cannula or were intubated; both modalities have drawbacks and may be associated with complications. Here we report our experience using a modified endoscopy mask, devised primarily for bronchoscopy, for upper endoscopy in children under general anesthesia.

RESULTS

Two hundred forty children (122 boys and 118 girls) participated in the study. Age range was 7 to 135 months (mean 60.7 +/- 34.4 months). All patients maintained a stable hemodynamic status throughout the procedure. Ventilation was satisfactory in 230 patients. It was difficult in 9 patients, and external airway maneuvers had to be applied. Ventilation was impossible in only 1 patient (10 months old), and endotracheal intubation was performed. There were no procedure-related complications.

CONCLUSION

The modified endoscopy mask is efficient and safe and should be recommended for routine use for upper endoscopy under general anesthesia in children older than 6 months.

Risk factors for hypoxemia during ambulatory gastrointestinal endoscopy in ASA I-II patients

BACKGROUND

Most studies identify the American Society of Anesthesiology (ASA) classification as the most significant risk factor for hypoxemia. The risk factors operative within ASA I and II patients are not well defined. Therefore, we analyzed prospectively collected data to identify the risk factors of hypoxemia in such patients.

METHODS

A combination of a narcotic and benzodiazepine was used for sedation and oxygen was supplemented if hypoxemia (oxygen saturation <or=90%) developed. Univariate and multivariate analyses were performed and correlations estimated for predetermined clinical variables.

RESULTS

40 of 79 patients (51%) developed hypoxemia, which occurred more frequently in the obese (71%; 10/14) than the nonobese (46%; 30/65) group (P=0.08). On multivariate analysis, the odds ratios (OR) and 95% confidence intervals (CI) for developing hypoxemia were age >or= 60 years 4.5 (1.4-14.3) P=0.01, and incremental 25-mg doses of meperidine 2.6 (1.02-6.6) P = 0.04. Body mass index (BMI) significantly correlated with the number of hypoxemic episodes (rho 0.26, 95% CI 0.04-0.48, P=0.02).

CONCLUSION

In ASA I and II patients, BMI significantly correlated with the number of hypoxemic episodes, whereas age >or= 60 years and meperidine dose were significant risk factors for hypoxemia.

Randomized clinical trial of Entonox versus midazolam-fentanyl sedation for colonoscopy

BACKGROUND

Intravenous sedation for colonoscopy is associated with cardiorespiratory complications and delayed recovery. The aim of this randomized clinical trial was to compare the efficacy of Entonox (50 per cent nitrous oxide and 50 per cent oxygen) and intravenous sedation using midazolam-fentanyl for colonoscopy.

METHODS

Some 131 patients undergoing elective colonoscopy were included. Patients completed a Hospital Anxiety and Depression questionnaire, letter cancellation tests and pain scores on a 100-mm visual analogue scale before, immediately after the procedure and at discharge. They also completed a satisfaction survey at discharge and 24 h after the procedure.

RESULTS

Sixty-five patients were randomized to receive Entonox and 66 to midazolam-fentanyl. Completion rates were similar (94 versus 92 per cent respectively; P = 0.513). Patients receiving Entonox had a shorter time to discharge. They reported significantly less pain (mean score 16.7 versus 40.1; P < 0.001), and showed better recovery of psychomotor function immediately after the procedure and at discharge. Patient satisfaction was higher among patients who received Entonox (median score 96 versus 89; P = 0.001).

CONCLUSION

Entonox provides better pain relief and faster recovery than midazolam-fentanyl and so is more effective for colonoscopy.

Unsedated upper endoscopy in children

BACKGROUND

EGD is essential to the investigation and treatment of GI disorders in children. Although safe, EGD has the potential for complications, in particular cardiopulmonary abnormalities associated with intravenous sedation. EGD is often performed in adults without sedation. Unsedated EGD is occasionally performed in children but has not been subjected to study. This study assessed the safety, efficacy, and feasibility of unsedated EGD in children.

METHODS

Selected, highly motivated children requiring EGD were offered the choice of sedation or no sedation for the procedure. Children recorded scores for pain (face scale) and anxiety (vertical visual analogue scale) before and after EGD. In addition, the times required to prepare the patient, perform the EGD, and recover the patient were recorded.

RESULTS

There was no difference in age, gender, or pre-EGD pain scores between children selecting sedation or no sedation. However, children selecting sedation had significantly higher pre-EGD anxiety scores than those who chose no sedation. Successful completion of EGD was similar for sedated (96.3%) and unsedated (95.2%) children. Post-EGD scores for anxiety were significantly decreased in those receiving sedation and unchanged in children who received no sedation. There was no significant change in post-EGD pain score in either group. Nearly 80% of children undergoing unsedated EGD would elect to forego sedation if EGD was needed again. Total procedure time was significantly longer in sedated versus unsedated children, reflecting longer preparation and recovery.

CONCLUSIONS

Unsedated EGD can be performed safely and successfully in children with good patient tolerance. There was a significant decrease in total procedure time for children who have unsedated EGD. Unsedated EGD should be considered a viable option for motivated children.

Underlying mechanisms of respiratory symptoms with esophageal acid when there is no evidence of airway response

Although a strong association exists between gastroesophageal reflux (GER) and asthma, results of studies designed to maximize the likelihood of identifying that GER worsens pulmonary function in patients with asthma have been negative or inconclusive. Asthma symptoms worsen during symptomatic reflux episodes, and asthma symptom severity correlates with the severity of symptomatic reflux. Various reasons have been proposed to explain these findings. Discomfort associated with GER can cause reflux-associated respiratory symptoms even when pulmonary function is normal. New findings suggest that increases in minute ventilation rather than inhibition of diaphragm activity are responsible for the changes in respiratory sensation during acid perfusion of the esophagus in nonasthmatic subjects. These results may also pertain to asthmatic patients, because increasing minute ventilation can cause dyspnea and bronchospasm in this population. Treating GER, either medically or surgically, may improve asthma symptoms by preventing GER-induced changes in minute ventilation.

Risk of sedation for upper GI endoscopy exacerbating subclinical hepatic encephalopathy in patients with cirrhosis

BACKGROUND

The risk of exacerbating subclinical hepatic encephalopathy associated with the administration of sedative drugs in patients with cirrhosis undergoing diagnostic upper gastrointestinal (GI) endoscopy for portal hypertension remains to be determined.

METHODS

Ten adult patients with cirrhosis completed number connection tests before sedation for endoscopy and at discharge from the endoscopy unit 2 hours post-procedure. Control patients consisted of five patients with cirrhosis undergoing the same procedure for the same indication who did not receive sedation and 12 patients with no evidence of liver disease who received sedation before diagnostic endoscopy for a variety of GI complaints. The control populations were age, gender, education level, and, in the case of patients with cirrhosis, Child Pugh s score matched to the patients with cirrhosis who received sedation.

RESULTS

The mean (+/- SEM) age of patients with cirrhosis who received sedation was 59.6 +/- 3.8 years. Seven of the ten (70%) were men. Their mean Child Pugh s score was 7.2 +/- 1.5. Nine of the ten (90%) had abnormal baseline number connection tests results (mean for the group 52.3 +/- 6.7 seconds) the extent of which correlated with Child Pugh s scores (p < 0.005). Individually, the baseline number connection tests results were normal in one (10%), mild in six (60%), moderate in one (10%), and severe in two (20%). After the procedure (before discharge) the mean number connection tests result was 61.5 +/- 7.9 seconds (p = 0.01 when compared with baseline). The results were now normal in none (0%), mild in four (40%), moderate in four (40%), and severe in two (20%). Pre- and post-procedure number connection tests results did not change in the non-sedated cirrhotic or sedated non-liver disease control patients.

CONCLUSIONS

The results of this study indicate that (1) the majority of patients with cirrhosis and suspected portal hypertension have evidence of subclinical hepatic encephalopathy, (2) the extent of encephalopathy correlates with the Child Pugh's score, (3) sedation with midazolam for upper GI endoscopy exacerbates the encephalopathy, and (4) this adverse effect is still evident 2 hours after the procedure.

Oxygen saturation during esophagogastroduodenoscopy in children: general anesthesia versus intravenous sedation

BACKGROUND

Hypoxia may occur in children undergoing upper digestive endoscopy under sedation. The purpose of this study was to compare the occurrence of desaturation during intravenous sedation with that which occurs during general anesthesia.

METHODS

Thirty-six patients between 3 months and 6 years old underwent a diagnostic esophagogastroduodenoscopy under sedation (n = 18) or general anesthesia (n = 18). Oxygen pulse oximetry, heart rate, and mean arterial pressure were monitored throughout the procedure. At the end of the procedure, the operator gave the value of the endoscopy satisfaction score on a scale of I (very good conditions) to IV (impossible procedure).

RESULTS

The minimum oxygen pulse oximetry value was significantly lower in the sedation group compared with that in the general anesthesia group (89 +/- 5 vs. 97 +/- 1; p < 0.001). In the general anesthesia group, the oxygen pulse oximetry level declined to less than 95% in only one child; but in the sedation group, it declined to less than 95% in 16 patients (5.5% vs. 89%). Nine patients had a profound desaturation in sedation group (oxygen pulse oximetry < 90%); no patients in the general anesthesia group had desaturation (50% vs. 0%). In the general anesthesia group, heart rate and mean arterial pressure remained stable during the whole procedure, whereas in the sedation group, heart rate and mean arterial pressure increased significantly during the procedure. The endoscopy satisfaction score was I in all 18 patients in the general anesthesia group, whereas in the sedation group, it was I in only 2 patients, II in 8 patients, and III in 10 patients.

CONCLUSIONS

These results confirm that hypoxia during upper digestive endoscopy in patients under sedation is a frequent occurrence in children. When compared with sedation, general anesthesia is a safer technique that prevents hypoxia and allows the gastroenterologist to perform the endoscopy under better conditions.

The effects of acid perfusion of the esophagus on ventilation and respiratory sensation

The relationship between gastroesophageal reflux (GER) and asthma remains controversial. Asthma symptoms worsen with GER, but are not consistently related to changes in lung function. The purpose of this study was to determine whether acid perfusion (AP) of the esophagus alters ventilation and causes respiratory symptoms. Nonasthmatic patients with normal lung function and esophageal disease (16 females and nine males, FEV1 %predicted = 99+/-9.6), underwent a Bernstein test after motility testing. Airflow, rib cage (Vrc), and abdominal (Vab) tidal volumes, esophageal (Pes) and gastric (Pga) pressure, and surface (Es) and esophageal (Edi) diaphragm electromyographic (EMG) signals were measured. Throat, swallowing, chest, and stomach discomfort and respiratory sensation were estimated with the Borg scale. Minute ventilation (VE) increased during AP and declined during recovery with saline perfusion of the esophagus (7.1+/-1.5 to 8.5+/-2.4 to 7.3+/-2.1 L/min; n = 25; p = 0.0002). Respiratory rate (RR) went from 13.6+/-2.6 to 15.8+/-3.4 to 15.3+/-3.1 breaths/min (n = 25; p = 0.0002) during AP. VE was greater in the Bernstein-positive patients during AP. Tidal volume (VT), Vrc, Vab, Pes, Pga, Es, and Edi did not change during AP. Chest discomfort (D) correlated with ventilation (VE = 0.7 + 0.8 D; r = 0.67; p < 0.001) and respiratory effort sensation (B) (B = 0.2 + 0.4 VE; r = 0.70; p < 0.001) during AP. AP did not inhibit diaphragm activity. Increased VE may explain the paradox of GER worsening respiratory symptoms without changing lung function.

Sedation and analgesia for colonoscopy: patient tolerance, pain, and cardiorespiratory parameters

BACKGROUND

Colonoscopy is generally performed with the patient sedated and receiving analgesics. However, the benefit of the most often used combination of intravenous midazolam and pethidine on patient tolerance and pain and its cardiorespiratory risk have not been fully defined.

METHODS

In this double-blind prospective study, 150 outpatients undergoing routine colonoscopy were randomly assigned to receive either (1) low-dose midazolam (35 micrograms/kg) and pethidine (700 micrograms/kg in 48 patients, 500 micrograms/kg in 102 patients), (2) midazolam and placebo pethidine, or (3) pethidine and placebo midazolam.

RESULTS

Tolerance (visual analog scale, 0 to 100 points: 0 = excellent; 100 = unbearable) did not improve significantly more in group 1 compared with group 2 (7 points; 95% confidence interval [-2-17]) and group 3 (2 points; 95% confidence interval [-7-12]). Similarly, pain was not significantly improved in group 1 as compared with the other groups. Male gender (p < 0.001) and shorter duration of the procedure (p = 0.004), but not amnesia, were associated with better patient tolerance and less pain. Patient satisfaction was similar in all groups. Oxygen desaturation and hypotension occurred in 33% and 11%, respectively, with a similar frequency in all three groups.

CONCLUSIONS

In this study, the combination of low-dose midazolam and pethidine does not improve patient tolerance and lessen pain during colonoscopy as compared with either drug given alone. When applying low-dose midazolam, oxygen desaturation and hypotension do not occur more often after combined use of both drugs. For the individual patient, sedation and analgesia should be based on the endoscopist's clinical judgement.

Hypoxemia during outpatient gastrointestinal endoscopy: the effects of sedation and supplemental oxygen

STUDY OBJECTIVES

To compare the effects on oxygen saturation as measured by pulse oximetry (SpO2) and ECG changes of endoscopy alone, sedation followed by endoscopy, and sedation followed by endoscopy with supplemental oxygen (O2) during upper gastrointestinal (GI) endoscopy.

STUDY DESIGN

Randomized trial.

SETTING

Outpatient gastroenterology clinic at a university medical center.

PATIENTS

58 healthy patients scheduled for outpatient upper GI endoscopy, with no clinical evidence of respiratory disease.

INTERVENTIONS

Patients were randomly allocated to three groups: Group 1 received no benzodiazepines before endoscopy and breathed room air throughout (n = 18), Group 2 received midazolam intravenously (i.v.) before endoscopy and breathed room air throughout (n = 20), and Group 3 received i.v. midazolam and 2 L/min O2 through nasal cannulae during endoscopy (Group 3; n = 20).

MEASUREMENTS AND MAIN RESULTS

Data collection, which included heart rate, cardiac rhythm, and SpO2 were recorded at seven intervals: baseline, topical anesthesia of the oropharynx, mouth gag insertion, endoscope insertion, biopsy, endoscope removal, and five minutes postendoscopy. In Group 2, mean SpO2 decreased after midazolam was administered and remained depressed during endoscopy (p < 0.05). After midazolam was given, Group 2 patients differed significantly from patients in Groups 1 and 3 (p < 0.05).

CONCLUSIONS

The use of hypnotic doses of benzodiazepines is the primary factor responsible for the reduced oxygenation seen during endoscopy. Neither the presence of the endoscope alone nor the use of midazolam with supplemental O2 caused a decreased oxygenation. This study also suggests that the routine use of benzodiazepines is unnecessary when the endoscopy is of short duration, and the endoscopist employs good topicalization of the oropharynx. In patients who require sedation for endoscopy, O2 administration prevents hypoxemia.

Conscious sedation for gastroscopy: patient tolerance and cardiorespiratory parameters

BACKGROUND/AIMS

Most patients receive conscious sedation for gastroscopy. However, the benefit of the most often used combination of low-dose intravenous midazolam and topical lidocaine on patient tolerance remains poorly defined and has not been shown to outweigh cardiorespiratory risks. To respond to these issues, a randomized, double-blind, placebo-controlled prospective study was performed.

METHODS

Two hundred outpatients undergoing diagnostic gastroscopy were assigned to receive either (1) midazolam (35 micrograms/kg) and lidocaine spray (100 mg), (2) midazolam and placebo lidocaine, (3) placebo midazolam and lidocaine, or (4) placebo midazolam and placebo lidocaine.

RESULTS

Tolerance (visual analogue scale, 0-100 points; 0, excellent; 100, unbearable) improved as compared with placebo midazolam and placebo lidocaine by 23 points (95% confidence interval, 15-32) in group 1, 15 points (95% confidence interval, 7-24) in group 2, and 10 points (95% confidence interval, 2-18) in group 3. Increasing age (P < 0.001), low anxiety (P < 0.001), and male sex (P < 0.03), but not amnesia, were associated with better patient tolerance. Oxygen desaturation (< 1 minute) occurred in 8.2% and was not more frequent after midazolam treatment. Hypotension was rare (2.1%), and no adverse outcome occurred.

CONCLUSIONS

Both low-dose midazolam (35 micrograms/kg) and lidocaine spray have an additive beneficial effect on patients tolerance and rarely induce significant alterations in cardiorespiratory monitoring parameters, thus supporting the widespread use of conscious sedation.

Choosing the correct pain relief for extracorporeal lithotripsy

OBJECTIVES

To determine the best choice of analgesic for patients undergoing lithotripsy, and to attempt to identify factors which might predict which patients are most likely to find the procedure painful.

PATIENTS AND METHODS

Sixty patients with stones in the pelvicalyceal system of the kidney were randomized prospectively to undergo lithotripsy with the Dornier MPL9000 lithotripter (Dormier Medical Systems, Marietta, GA, USA) after receiving either diclofenac 100 mg per rectum (n = 30) or pethidine 50 mg intravenously (n = 30) for analgesia. The patients completed a detailed questionnaire prior to treatment, and the level of pain perceived during lithotripsy was monitored using visual analogue scales (VASs). Arterial oxygen saturation (SaO2) was monitored before analgesia was given, throughout the treatment and for 30 min after cessation of treatment.

RESULTS

The VASs were available for 56 patients and the results of pulse oximetry for 51 patients. Although a higher kilovoltage was recorded in the group who received pethidine this difference was not significant. Patients who received diclofenac or pethidine alone, showed a non-significant fall of SaO2 30 minutes after the end of treatment, although the largest fall in SaO2 observed with pethidine was 10%. Patients who received diclofenac and pethidine similarly showed a non-significant fall in SaO2. Four patients received intravenous benzodiazepines in addition to pethidine, and in this group there was a dramatic fall in SaO2 which persisted more than 30 min after the end of treatment (P < 0.0027). Diclofenac provided effective analgesia for most of the patients who underwent lithotripsy. Overall 11 patients (18%) required additional analgesia. Diclofenac or pethidine alone, in the doses used in this study, did not cause a significant drop in SaO2 during ESWL. The only response found to be of value in predicting a painful experience was fear of the dentist.

CONCLUSIONS

This study shows that modern lithotripsy, in addition to being safe and effective, can be performed as an out-patient procedure using simple non-opiate analgesics. The need for stronger analgesia and/or sedation should be tailored to the needs of the individual patient, although it remains difficult to predict which patients will require such measures.

Effects of supplemental oxygen on cardiac rhythm during upper gastrointestinal endoscopy: a randomised controlled double blind trial

To investigate the effects of supplemental oxygen on cardiac rhythm during gastroscopy, 103 patients aged over 60 were randomised to receive either supplemental oxygen or air at 2 litres/minute during the procedure. Pulse rate, blood pressure, oxygen saturation, and a Holter cardiac trace were monitored before, during, and for one hour after the gastroscopy. A wide range of electrocardiographic abnormalities were recorded in both oxygen and air groups, of which ventricular and supraventricular ectopic beats were the most common. There were no significant differences in the rate of occurrence of any clinically important cardiac abnormality either between the oxygen and air groups or between the three monitored periods before, during, and after gastroscopy. There were significantly fewer patients, however, with supraventricular extra systoles when oxygen was given during gastroscopy (p < 0.05). Although supplemental oxygen during gastroscopy significantly improved oxygen saturation (p < 0.001; 95% confidence intervals for the difference between the means: 2.9 to 4.7), there was no correlation between oxygen saturation and any electrocardiographic changes. It is concluded that electrocardiographic abnormalities are common in patients over 60, but this study found no evidence that they are induced by gastroscopy. Supplemental oxygen increases oxygen saturation but does not reduce the incidence of clinically important cardiac arrhythmias.

Safety of fibreoptic endoscopy: analysis of cardiorespiratory events

Cardiorespiratory function during upper gastrointestinal endoscopy and colonoscopy was studied prospectively in 164 patients. Cardiorespiratory events, which were defined as oxygen saturation < 90 per cent, electrocardiographic changes, heart rate < 50 or > 100 beats/min and systolic blood pressure < 100 mmHg, occurred in 111 patients. In 24 of these, changes were attributed solely to intravenous sedation. In the remaining 140 patients, events were noted in 34 (52 per cent) of 66 upper gastrointestinal endoscopies and during 53 (72 per cent) of 74 colonoscopies. One patient suffered a myocardial infarction during colonoscopy. Although cardiorespiratory events were common (111 of 164; 68 per cent), the actual morbidity rate was low (one of 164; 0.6 per cent). Cardiorespiratory events were significantly more common in patients with a history of cardiac disease for both upper gastrointestinal endoscopy and colonoscopy (overall chi 2 = 7.41, 1 d.f., P < 0.05) and more common for oesophageal dilatation than for diagnostic endoscopy (chi 2 = 5.56, 1 d.f., P < 0.05). It is recommended that patients with a history of cardiac problems undergoing upper gastrointestinal endoscopy or colonoscopy and all those requiring therapeutic endoscopy should be monitored carefully to allow early detection of cardiorespiratory events, and that oxygen should be administered routinely.

Monitoring and safety in endoscopy

Over 50% of the complications and 60% of the deaths associated with upper GI endoscopy are cardiopulmonary in type. Oxygen desaturation and cardiac arrhythmias at the time of endoscopy are common. Ways of trying to prevent hypoxia occurring are discussed. The most effective of these is the use of supplemental oxygen. Pulse oximeters are being used increasingly frequently by endoscopists. The way in which oximeters work is described in some depth, as are some of the potential errors that may result from their use. The author believes that, as in anaesthetic practice, pulse oximeters will be used ever more frequently by endoscopists and finally become standard equipment in all endoscopy units. The case for using continuous ECG monitoring and blood pressure measurement is briefly discussed. The ASGE have recently published their recommendations on monitoring patients undergoing GI endoscopic procedures. The BSG's own working party on safety and monitoring is in the process of finalizing its recommendations, and the final part of the chapter discusses the views of this working party and gives some insight into what its final recommendations are likely to be.

Oxygen saturation monitoring during endoscopy

The role of monitoring during endoscopy is not clearly defined. We have prospectively investigated continuous arterial oxygen saturation (SaO2) monitoring in 326 patients undergoing upper endoscopy (EGD) and 90 undergoing colonoscopy. Automated blood pressure recording was evaluated in 278 of these patients. SaO2 desaturation (less than 90%) occurred in 17.8% of patients undergoing EGD and 12.9% undergoing colonoscopy. Systolic blood pressure abnormalities (greater than 200 or less than 90 mmHg) occurred in 19.8% of EGD patients and 19.6% of colonoscopy patients. Treatment based on these abnormalities was required in 4.3% of patients during EGD and 8.8% during colonoscopy. A history of pulmonary or cardiac disease predicted increased risk during colonoscopy, while cardiac disease and age 60 years or above predicted desaturation during EGD. Pulse oximetry and automated blood pressure monitoring was especially valuable during endoscopy in the elderly and patients with cardiac or pulmonary disease. It may be used as a guide to therapeutic intervention and to avert major cardiopulmonary complications.

Evaluation of safe, effective intravenous sedation for utilization in endoscopic procedures

The prevention of anesthetic mishaps during endoscopic procedures is of great importance to physicians in training. With the large number of such procedures performed each year, even infrequent adverse anesthetic reactions may result in a significant number of problems. To establish the safety and efficacy of an anesthetic regimen using intravenous meperidine and diazepam, all endoscopic procedures performed at one teaching institution in a 4-month period were retrospectively analyzed with regard to: (1) type and dosage of sedation/anesthesia, (2) endoscopic procedure involved, (3) effect of any underlying disease state, (4) side effects, (5) endoscopic complications, and (6) overall patient acceptance. A total of 716 patients underwent 913 endoscopic procedures with 876 separate anesthetic/intravenous sedations. General anesthesia was utilized in 44% of the 155 pediatric procedures. In the adult patients, intravenous sedation was administered by a physician-in-training under supervision except in 9% of cases (66 patients) when intravenous sedation utilizing alternative agents was given by the anesthesia department. The dose of sedation used (per body weight) declined with increasing age in the pediatric group (0-19 years). The adult dose remained constant for the next eight decades of life (meperidine 0.76 +/- 0.33 mg/kg: diazepam 0.12 +/- 0.08 mg/kg). In the adult group, 758 procedures were performed: 371 patients underwent esophago-gastroduodenoscopy, 258 colonoscopy, 36 endoscopic retrograde cholangiopancreatography, 40 flexible sigmoidoscopy, and 51 percutaneous endoscopic gastrostomy. Anesthetic-related complications (transient apnea and itching), were noted in two patients, and naloxone was utilized to reverse oversedation in a further 17 (2.56%).(ABSTRACT TRUNCATED AT 250 WORDS)

Bolus or slow titrated injection of midazolam prior to upper gastrointestinal endoscopy? Relative effect on oxygen saturation and prophylactic value of supplemental oxygen

A total of 131 patients undergoing upper gastrointestinal endoscopy were sedated with midazolam given as a bolus injection over 5 seconds. The oxygen saturation was continuously measured using a pulse oximeter. Supplemental oxygen was given via nasal cannulae at a rate of 3 litres per minute to 54 patients, while the remaining 77 patients only received oxygen if their oxygen saturation dropped below 85%. Both groups in the present series were compared with 3 previously published series of patients, in whom we had used intravenous midazolam as a slow titrated injection. Despite using on average only two-thirds of the dose of midazolam, following bolus injection the degree of oxygen desaturation during the endoscopic procedure was greater, and the ability of supplemental oxygen delivered via nasal cannulae to prevent hypoxia was less (P less than 0.01), than with a slow titrated injection.

Review article: premedication and intravenous sedation for upper gastrointestinal endoscopy

Upper gastrointestinal endoscopy can be performed without intravenous sedation but the evidence suggests that, in the United Kingdom and United States, most patients and endoscopists prefer that some form of premedication is given. Intravenous diazepam or midazolam are used by the majority of endoscopists. In the UK, the ratio of diazepam to midazolam users is approximately 2:1, while in the USA more endoscopists are now using midazolam. Midazolam is approximately twice as potent as diazepam but, when allowance is made for this, there is probably little or no difference in the propensity of the two drugs to produce respiratory depression. The antegrade amnesic effect of midazolam is significantly superior to that of diazepam. A benzodiazepine/narcotic combination can achieve a smoother and more rapid induction with less gagging and choking, but the incidence of adverse outcomes--particularly respiratory depression--is increased significantly. Over 50% of the deaths that are associated with upper gastrointestinal endoscopy are due to cardiopulmonary problems. Hypoxia is very common if measured using non-invasive monitoring equipment, such as a pulse oximeter. Methods of preventing oxygen desaturation and thus, by inference, most cardiac arrhythmias associated with endoscopy are discussed, as is the role of flumazenil, the new benzodiazepine antagonist.