Nasal high flow improves ventilation during propofol sedation: A randomized cross-over study in healthy volunteers

Objective: Hypoventilation and carbon dioxide (CO2) retention are common during sedation. The current study investigated the ventilation responses to nasal high flow (NHF) during sedation with propofol. Methods: NHF of 30 L/min and 60 L/min with room air was applied during wakefulness and sedation in 10 male volunteers. Ventilation was monitored by respiratory inductance plethysmography, transcutaneous partial pressure of CO2 (TcCO2), and SpO2. Results: During sedation, NHF of 30 L/min and 60 L/min reduced the TcCO2 by 2.9 ± 2.7 mmHg (p = 0.025) and by 3.6 ± 3.4 mmHg (p = 0.024) without affecting SpO2 and reduced the mean respiratory rate by 3 ± 3 breaths/min (p = 0.011) and by 4 ± 3 breaths/min (p = 0.003), respectively. Conclusion: During sedation with propofol, NHF without supplemental oxygen attenuated CO2 retention and reduced the respiratory rate. The findings show that NHF can improve ventilation during sedation, which may reduce the risk of complications related to hypoventilation

The effect of midazolam administration for the prevention of emergence agitation in pediatric patients with extreme fear and non-cooperation undergoing dental treatment under sevoflurane anesthesia, a double-blind, randomized study

Background: Sevoflurane is generally the preferred anesthetic agent for general anesthesia in pediatric patients, due to its rapid induction and recovery characteristics. However, it has been recognized that a major complication is emergence agitation when awakening from general anesthesia. The aim of this study was to evaluate the occurrence rate of emergence agitation in the operating room and postoperative recovery area following intraoperative administration of midazolam to pediatric patients under general anesthesia. Patients and methods: One hundred and twenty pediatric patients undergoing dental treatment under sevoflurane anesthesia were enrolled in this study. The patients were divided into three groups (n=40 each in the 0.1 mg/kg midazolam, 0.05 mg/kg midazolam, and control with saline groups). Midazolam or saline was injected intravenously approximately 30 minutes before the end of the dental treatment. We used the Richmond Agitation and Sedation Scale (RASS) to assess the level of sedation and drowsiness at emergence phase in the operating room. We also used the Pediatric Anesthesia Emergence Delirium Scale (PAED) to assess the level of agitation and delirium at the full recovery phase from anesthesia in the recovery area. Results:At the emergence phase, the incidence of emergence agitation in the 0.1 mg/kg midazolam group was significantly lower than in the other groups (p=0.0010). At the recovery phase, there was no significant difference among the three groups. The odds ratio between PAED score and RASS score was 4.0 using logistic regression analysis. The odds ratio between PAED score and Disability was 2.5. Conclusion: Administration of a single dose of 0.1 mg/kg midazolam dose significantly decreases the incidence of severe emergence agitation at the emergence after sevoflurane anesthesia, but not at the recovery phase. Furthermore, the evaluation of sedative and agitation condition using RASS score at emergence from anesthesia is useful to predict occurrence of agitation in the recovery phase

Upper-airway collapsibility and compensatory responses under moderate sedation with ketamine, dexmedetomidine, and propofol in healthy volunteers

Background: Ketamine is a potent sedative drug that helps to maintain upper-airway patency, due to its higher upper-airway dilator muscular activity and higher level of duty cycle, as seen in rats. However, no clinical trials have tested passive upper-airway collapsibility and changes in the inspiratory duty cycle against partial upper-airway obstruction in humans. The present study evaluated both the passive mechanical upper-airway collapsibility and compensatory response against acute partial upper-airway obstruction using three different sedative drugs in a crossover trial. Methods: Eight male volunteers entered this nonblinded, randomized crossover study. Upper-airway collapsibility (passive critical closing pressure) and inspiratory duty cycle were measured under moderate sedation with ketamine, propofol, and dexmedetomidine. Propofol, dexmedetomidine, and ketamine anesthesia were induced to obtain adequate, same-level sedation, with a BIS value of 50?70 and the OAA/S score of 2?3 and RASS score of ?3. Results: The median passive critical closing pressure of 0.08 [?5.51 to 1.20] cm H2O was not significantly different compared to that of propofol sedation (?0.32 [?1.41 to ?0.19] cm H2O) and of dexmedetomidine sedation (?0.28 [?0.95 to ?0.03] cm H2O) (p =.045). The median passive RUS for ketamine 54.35 [32.00 to 117.50] cm H2O/L/s was significantly higher than that for propofol 5.50 [2.475 to 19.60] cm H2O/L/s; (mean difference, 27.50; 95% CI 9.17 to 45.83) (p =.009) and for dexmedetomidine 19.25 [4.125 to 22.05] cm H2O/L/s; (mean difference, 22.88; 95% CI 4.67 to 41.09) (p =.021). The inspiratory duty cycle increased significantly as the inspiratory airflow decreased in passive conditions for each sedative drug, but behavior differed among the three sedative drugs. Conclusion: Our findings demonstrate that ketamine sedation may have an advantage of both maintained passive upper-airway collapsibility and a compensatory respiratory response, due to both increase in neuromuscular activity and the increased duty cycle, to acute partial upper-airway obstruction

A study on respiratory management in acute postoperative period by nasal high flow for patients undergoing surgery under general anesthesia

In head and neck surgery where the oropharyngeal area is the operative field, postoperative respiratory depression and upper airway obstruction are common. Therefore, supplemental oxygen is administered to prevent severe postoperative early hypoxemia. However, a high concentration of oxygen increases the likelihood of secondary complications, such as carbon dioxide (CO2) narcosis. Nasal high-flow (NHF) therapy generates high flows (?60?L/min) of heated and humidified gas delivered via nasal cannula and provides respiratory support by generating positive airway pressure, clearance of dead space and reduction of work of breathing. This study aims to determine whether the postoperative hypoxemia and hypercapnia can be prevented by NHF without the requirement of supplemental oxygen. The study will recruit adult patients undergoing planned oral surgery under general anesthesia at Nagasaki University Hospital. It is a randomized parallel group comparative study with 3 groups: NHF with room air only and no supplemental oxygen, no respiratory support, and face mask oxygen administration. The study protocol will begin at the time that the patient is returned to the general ward and will finish 3?hours later. The primary endpoint is the time-weighted average of transcutaneous O2 over the 180 minutes and secondary endpoints are the time-weighted average of transcutaneous CO2 (tcpCO2), SpO2, and respiratory rate, incidence rate of marked hypercapnia (tcpCO2 ?60 mm Hg for 5 minutes or longer), incidence rate of moderate hypercapnia (tcpCO2 ?50 mm Hg for 5 minutes or longer) and the percentage of time that SpO2 is <90%. Included also is a group in which the postoperative management is performed only by spontaneous breathing without performing respiratory support such as oxygen administration, to investigate the efficacy and necessity of conventional oxygen administration. This exploratory study will investigate the use of NHF without supplemental oxygen as an effective respiratory support during the acute postoperative period. TRIAL REGISTRATION:: The study was registered the jRCTs072200018. URL https://jrct.niph.go.jp/latest-detail/jRCTs072200018

Zn(II) released from zinc oxide nano/micro particles suppresses vasculogenesis in human endothelial colony-forming cells

Zinc oxide (ZnO) nanoparticles have been widely used in industry, cosmetics, and biomedicine. Recent studies suggested that these nanoparticles could have a major impact on the cardiovascular system. Endothelial progenitor cells (EPCs) contribute to postnatal endothelial repair and regeneration. The present study dissected the effects of ZnO nanoparticles on vasculogenesis using human endothelial colony forming cells (ECFCs), which participate in post-natal vasculogenesis. Two types of ZnO particles were used (nano and micro), in addition to zinc chloride solutions with zinc ion concentrations equal to those in ZnO nanoparticles. Twenty-four-hour exposure induced cytotoxicity in a dose-dependent manner and increased ECFCs apoptosis in all groups. The exposure also reduced the functional capacity of ECFCs on Matrix gel to form tubules, compared with the control cells. These effects were associated with downregulation of expression of vascular endothelial growth factor receptor, VEGFR2 and CXC chemokine receptor, CXCR4. The results suggest that ZnO nanoparticles suppress vasculogenesis from ECFCs through downregulation of the expression of receptors related to vasculogenesis. These effects are based the concentration of released Zn(II)

Efficacy of nasal high flow therapy on the coordination between breathing and swallowing of saliva during daytime nap in chronic obstructive pulmonary disease patients

BACKGROUND: There are some clinical reports on dysphagia in patients with chronic obstructive pulmonary disease(COPD);however, its pathophysiology remains largely unknown.Changes in respiratory function occur in patients with COPD causing a decrease in tidal volume and an increase in respiratory rate (tachypnea). In addition, it leads to lack of coordination between respiration and swallowing.A new treatment called nasal high flow (NHF) has been introduced for patients with COPD, replacing the traditional non-invasive ventilation (NIV) procedure. The NHF therapy involves inhalation of high flow of humidified air, which reduces respiratory effort in patients with COPD. Furthermore,NHF therapy facilitates swallowing of saliva even during respiratory management. A recent clinical study reported that high-flow nasal cannula oxygen therapy for 6 weeks improved the health-related quality of life and reduced hypercapnia in patients with stable COPD. Taken together, NHF therapy is gaining attention in the clinical management of patients with COPD.Therefore, in this study, we aim to examine the efficacy of NHF therapy on the coordination between breathing and swallowing of saliva during daytime nap in patients with COPD. METHODS/DESIGN: This open-label,investigator-initiated, single center study will evaluate the efficacy of NHF therapy on the coordination between breathing and swallowing of saliva during the daytime nap in COPD patients with forced expiratory volume in 1?second (FEV1%) of <70% during treatment at the Nagasaki University Hospital Respiratory Rehabilitation Center. Evaluations will be performed during the 90 to 180?minute "daytime nap" in the measurement room of the hospital.The primary endpoint will be the rate of appearance of the expiratory phase after swallowing of saliva and the frequency of swallowing during the measurement period. DISCUSSION: The purpose of this study is to obtain evidence regarding the utility of NHF as a potential therapeutic device for COPD patients to prevent aspiration of saliva during the sleep stage of daytime nap. The utility will be assessed by comparing the decrease in incidence rates of the expiratory phase after swallowing of saliva in the NHF device group and the control group, wherein this device was not used

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.URLhttps://jrct.niph.go.jp/en-latest-detail/jRCTs072190022

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