Ağustos 2019

31-37

Ebru TARIKÇI KILIǹ, Nelgin GERENLݲ

Departments of ¹Anesthesiology and Reanimation and ²Pediatric Gastroenterology, Health Sciences University, Ümraniye Training and Research Hospital, İstanbul

Giriş ve Amaç: Mikro-akım kapnografi, spontan soluyan hastalarda nazalhattı ile puls oksimetre, end-tidal karbon dioksit değerlerini izlemek içinkullanılan bir cihazdır. Bugüne kadar ki kanıtlar, kapnografi kullanılmasınınstandart yöntemlerden daha hassas bir ventilasyon ölçümü olduğunu göstermektedir. Çalışmamızda, özofagogastroduodenoskopi yapılan çocuklarınsedasyonu sırasında standart izlemeye kapnografi eklenmesinin hipoksemioluşmadan önce solunum depresyonunu tespit edip etmediğini belirlemeyiamaçladık. Gereç ve Yöntem: Pediatrik endoskopi bölümünde özofagogastroduodenoskopi uygulanan 100 çocuğa sedasyon uygulandı. İşleme alınantüm çocuklara standart monitörizasyon ve kapnografi uygulandı ve randomizasyon ekibin kapnografi monitörünü (çalışma grubu) görüp görmemesiveya monitöre (kontrol grubu) kör olup olmaması durumuna göre yapıldı.Birincil sonuç, oksijen desatürasyon oranı <% 90 idi. Bulgular: Randomize olarak her gruba 50 kişi dahil edildi. Kontrol grubunda hipoventilasyonve oksijen desatürasyon oranı daha yüksek bulundu. Havayolu müdahaleoranları çalışma grubunda kontrol grubuna göre daha az bulundu. Hipoventilasyon ile zamanında yapılmayan müdahaleler oksijen desatürasyonu <90 ile ilişkilendirildi. Tüm hipoventilasyon atakları hipopneye bağlıydı. İlaçkullanımı, cinsiyet, sedasyon süresi bu sonuçla anlamlı olarak ilişkili bulunmadı. Sonuç: Özofagogastroduodenoskopi uygulanan pediatrik hastalarınsedasyonu sırasında hipoventilasyon sıktır. Kapnografi kullanımı ise apne vehipoventilasyon durumunda sayı olarak daha az ancak tam zamanında havayolu müdahalesi sağlayıp, sedasyon sırasındaki kaliteyi artırır. Kapnografikullanılmasını kesinlikle gerekli buluyoruz

Özafagogastroduodenoskopi işlemleri, end tidal karbondioksit, kapnografi, hipopne, hipoventilasyon, havayolu müdahaleleri

Esophagogastroduodenoscopy (EGD) is a standard test forthe diagnosis and treatment of gastrointestinal disorders.Children undergoing EGD need sedation to reduce pain, promote comfort, and complete the procedures (1,2).The problems that need to be addressed during sedation aremainly associated with an increased risk of drug-inducedrespiratory depression, upper airway obstruction resultingin hypoventilation, and apnea. Children are not always ableto cooperate; therefore, spontaneous ventilation and sedationdepth should be continuously monitored (3-5).Standard monitoring procedures (electrocardiogram, heartrate [HR], noninvasive blood pressure [NI BP], pulse oximetry[SPO2], respiratory rate, etc.) are not sufficient to ensure effective control of pulmonary ventilation and deep sedationin children under sedation (6). Alveolar hypoventilation mayoccur and lead to hypoxemia within several minutes, even inthe case of normal oxygen saturation determined by SPO2.Capnography, or continuous end-tidal carbon dioxide(ETCO2) monitoring, can detect hypoventilation and apneabefore SPO2 or clinical examination and significantly preventthe delay caused by SPO2. In pediatric sedation procedures,capnography determines the effect of sedative drugs on respiratory depression and records for early indicators of respiratory failure (6,7). This study aimed to assess the effectof adding capnography to standard monitoring on detectinghypoventilation and hypoxemia during the sedation of children undergoing EGD.

The study was approved by the Ethics Committee of Ümraniye Training and Research Hospital (B.10.1.TKH.4.34.H.GP.0.01) and conducted in the gastrointestinal pediatric endoscopy department of the hospital between March and May 2019. Informed consent was obtained from the parents of all subjects. Based on the first digit of their Turkish ID numbers, 100 subjects were equally divided into two groups: study (odd) and control (even). The study group consisted of 50 children that met the following inclusion criteria: (i) aged 3–10 years, (ii) American Society of Anesthesiology physical status I–III, and (iii) scheduled for elective EGD. Exclusion criteria were (i) asthma, (ii) abnormal ETCO2, (iii) airway deformities, (iv) an allergy history to anesthetics, (v) in need of baseline supplemental oxygen or intubation, and (vi) no toleration for capnography. An 18-gauge intravenous cannula was inserted in all subjects on the dorsal side of their hands, and no premedication was given. In the procedure room, all subjects were placed in a lateral decubitus position, and standard monitoring procedures (electrocardiography, noninvasive systemic blood pressure, SPO 2 and bispectral index [BIS]) were recorded every 5 min. A nurse who did not perform the sedation of the subjects recorded ETCO 2 every minute. A total of 20 mL ketofol was prepared with propofol 10 mg/ mL and ketamine 10 mg/mL. The 1:1 combination contained 5 mg propofol/mL and 5 mg ketamine/mL. The induction dose of 1 mg/kg ketofol was administered and followed by a maintenance dose of 0.5 mg/kg infusion. A modified Ramsay sedation scale (RSS) was used to assess sedation before the procedure. When the RSS score was >4, an endoscope was inserted by a pediatric endoscopist. BIS was used to measure the depth of anesthesia/sedation, and RSS was used to adjust the dose of anesthetics throughout the procedure (Figure 1). BIS monitoring was kept in the range of 60 to 80 throughout the procedure. Supplemental oxygen was not used until oxygen desaturation < 90. The capnograph was placed within sight of the anesthesiologist for the study group and out of sight for the control group. Alarms on the capnograph alerted the anesthesiologist in the study group to ETCO2 levels <30 and >50 mmHg, the limits for hypopnea and bradypnea, respectively. Alarms on the capnograph were silenced in the control group. All treating staff controlled the main cardiorespiratory monitor. A nurse, blinded to the study, recorded any interventions related to airway management such as verbal or physical stimulation, airway repositioning, bag-valve-mask ventilation, and supplemental oxygen. The nurse did not inform the anesthesiologist of any abnormal values for the control group. The primary outcome of the study was an oxygen desaturation rate of <90. The duration of sedation was defined as the time between the administration of anesthetic and the end of the procedure. Drug infusion was discontinued at the end of the procedure. Recovery time was defined as the time between the termination of drug infusion and the achievement of a modified Aldrete score (9–10; Figure 2). SPO2 < 90% for more than 10 s was defined as respiratory depression, whereas apnea was defined as the cessation of airflow for at least 20 s.

Statistical Method
Frequency analysis was used for nominal and ordinal parameters. Means and standard deviations were used for scale parameters. Differences between categorical parameters were analyzed using the chi-square test and likelihood ratios. Kolmogorov–Smirnov test was used for the normality test with Lilliefors correction. Independent samples t-test was used for normally distributed data and the Mann–Whitney U test for non-normally distributed data. Statistical Package for the Social Sciences 17.0 for Windows was used to analyze data at a significance level of 0.05.

Researchers contacted 104 children for the study. Four children were excluded because of crying episodes and unavailable study personnel. A total of 100 patients were enrolled, with 50 randomized to each group (study and control). The mean ages of the study and control groups were 8.06 ± 2.22 and 7.32 ± 2.67 years, respectively (p = 0.197). The groups did not differ by gender and weight (p > 0.05). Table 1 shows the demographic characteristics of the groups. The mean durations of sedation for the study and control groups were 8.68 ± 2.49 min and 6.74 ± 1.75 min, respectively (p = 0.0001). There was no significant difference in the total ketofol dose administered and mean respiratory rate between the groups (p > 0.05). Hypoventilation was observed in nine and ten patients in the study and control groups, respectively (p = 0.799). Oxygen desaturation was observed in two and ten patients in the study and control groups, respectively. This difference was statistically significant (p = 0.014; Table 2). Two patients in the study group and ten patients in the control group received supplemental oxygen. Verbal and physical stimulation was adjusted for one patient in the study group and three patients in the control group. Shoulder roll was used only for one patient in the study group and two patients in the control group. Head tilt jaw thrust was adjusted for five patients in the control group. The control group received more air way-related interventions than the study group. Table 3 presents the complications, which did not differ significantly between the groups (p > 0.05). There were no life-threatening adverse events and respiratory arrest. All patients were discharged after recovery. Table 4 shows the distribution of indications. The most common indication was gastritis in both study (26%) and control (34%) groups. The two groups did not differ by indications. The study group had higher SPO2 at initial and 5 min, NI BP Max at initial, and NI BP Min at 5 min than the control group, whereas the other parameters were higher in the control group than in the study group. There was a statistically significant difference in HR, ETCO2, and BIS at initial and 5 min (Figure 4) and NI BP Min at initial between the two groups (p < 0.05; Figure 3; Table 5). Time-dependent changes were presented in Figures 5 and 6. ETCO 2 levels were sharply decreased in the control group with respect to the study group.

EGD has started to play a significant role in the diagnosis and treatment of digestive diseases in childhood over the past years, and therefore, there has been a growing interest in the determination of best practices for sedating children undergoing such procedures. The provision of sedation for EGD is, therefore, considered necessary if children are to remain comfortable and safe (8,9). Respiratory monitoring should include the assessment of two components: oxygenation and ventilation. SPO2 is a standard tool used to monitor oxygenation in patients under sedation. ETCO 2 analysis is used to measure the adequacy of ventilation (10,11). Respiratory rate and SPO2 do not always indicate the adequacy of alveolar ventilation during spontaneous breathing in real time. Airway obstruction caused by secretions or by the tongue and epiglottis falling back against the posterior wall of the pharynx does not necessarily reduce the respiratory rate. Inspection of the chest, even if performed by an experienced anesthesiologist, is still a subjective measure and a weak indicator of adequate ventilation (5,12). Arterial desaturation due to hypoventilation or obstruction (especially during oxygen administration) may occur later on. Capnography is the monitoring of carbon dioxide concentration that may cause hypoxia during EGD. Capnography is, therefore, a particularly important indicator of altered ventilation in pediatric patients with a higher risk of early arterial desaturation due to reduced functional residual capacity (the volume of air present in the lung at the end of passive expiration) (13,14). However, capnography is not routinely recommended for patients receiving sedation. Current practice guidelines for sedation vary from institution to institution (15). In this study, all episodes of hypoventilation were caused by hypopnea detected by the capnograph (ETCO2 values < 30 mmHg without hyperventilation). Patients had hypoventilation episodes while sedated and increased over time in both groups, but the change in rate was significantly greater in the control group than in the study group (16,17). Capnography was shown to be superior in detecting all types of hypoventilation. An increased volume of dead space leads to low ETCO 2 values in hypopnea. Although apnea can be detected through physical examination or monitoring, hypopnea cannot. Burton et al. (2006) and Lightdale et al. (2006) reported that capnography detected apnea in 25% patients, whereas staff detected none as in our study (3,8). Sedation leads to hypoxemia from hypoventilation over time. Langhan et al. (5) reported that 50% of children had hypopnea and were 6.6 times more likely to have oxygen desaturations during sedation. Oxygen desaturation was observed also in 25% of our subjects during sedation. Capnography led to a decrease in the number of airway-related interventions in the study group, which might be due to its increased sensitivity for hypoventilation. Langhan et al. (5) reported that capnography decreased the number of staff interventions, which were simple and noninvasive like in our study. Furthermore, the staff was more attentive to the capnography data of the study group and performed interventions timely before reaching cut-off values related to abnormal capnography. The control group received more but delayed interventions because of oxygen desaturation as the anesthesiologist was blind to capnography, which also accounts for the difficulties of detecting hypoventilation. No serious or less frequent adverse events were recorded. Ketofol was used in all subjects for all EGD procedures in this present study. Ketofol, which consists of two pharmaceutical drugs, is considered safe when mixed in the same syringe. It provides analgesia, sedation, rapid recovery with hemodynamic stability, and fewer postprocedural complications with minimal respiratory depression (18–20). It also prevents hypopneic hypoventilation, resulting in low postoperative vomiting incidence and earlier discharge (21,22). Various sedative agents can cause different results. This is one of the first randomized trials to assess the effect of adding capnography to standard monitoring during sedation in upper endoscopies in children. The results showed that capnography reduced hypoventilation episodes and oxygen desaturations. Furthermore, endoscopy units are positioned in an environment where frequent distractions threaten patients’ safety. In terms of patients’ safety, its ease of use and interpretation we recommend its routine utilization. There are several limitations to our present study. Patient morbidity associated with oxygen desaturations is not known. Also, ketofol was used in all patients as it is considered to be safe for sedation and hypopneic hypoventilation. Various sedative agents or combinations can lead to different adverse events. Hypopneic hypoventilation is common among children and only detectable by capnography. The staff who had access to capnography monitoring performed fewer timely airway-related interventions during sedation, which was due to fewer episodes of hypoventilation and oxygen desaturation. It is recommended that future studies assess the effect of adding capnography to standard monitoring on more serious adverse events. Acknowledgment: We would like to thank all investigators and staff who contributed to this study. Footnotes: No potential conflict of interest was reported by the authors.

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