End-expiratory Carbon Dioxide Research Articles

Effect of patient position on the EEG bispectral index and entropy index under general anaesthesia.

Perioperative depth monitoring techniques, such as electroencephalography bispectral index (BIS), entropy index, and auditory evoked potential, are commonly used to assess anesthesia depth. However, the influence of patient positioning changes, particularly in gynecological surgeries where a head-down position is often required, on the accuracy of these monitoring indices remains unexplored. The aim of the our study was to observe the impact of patient position changes on the monitoring value of entropy and BIS to identify a more sensitive method of anaesthesia depth monitoring for gynaecological surgery patients. We conducted a study involving 40 women undergoing general anesthesia, during which routine monitoring of vital signs, including electrocardiogram (ECG), heart rate (HR), noninvasive arterial blood pressure (NIBP), oxyhemoglobin saturation (SpO2), and end-expiratory carbon dioxide (PetCO2), was initiated. Entropy and BIS devices were affixed to the patients' foreheads after alcohol sterilization to record brain activity. Tracheal intubation was performed following anesthesia induction. Throughout anesthesia maintenance, the value of BIS and response entropy (RE) were monitored and maintained between 40 and 50 by adjusting the infusion rate of propofol and remifentanil with Target Controlled Infusion (TCI, Mintopharmacokinetics model). Dosing for infusion control utilized corrected weight (height-105). Data were recorded before and after position changes, including tilting the operating table to head-down positions of 15 and 25 degrees, returning to a supine position, and elevating the head to 15 and 25-degree angles. BIS and entropy values at different time points were compared between the groups. Both BIS and entropy values increased from supine to head-down position and decreased from supine to head-up position, with entropy changes preceding those of BIS. Heart rate increased after head-up and decreased after head-down, while mean blood pressure (MBP) exhibited the opposite effect on heart rate. Significant correlations were found between heart rate and BIS (correlation coefficient: -0.43) and RE (correlation coefficient: -0.416), as well as between MBP and BIS (correlation coefficient: 0.346) and RE (correlation coefficient: 0.384). Changes in patient position can significantly affect the value of RE and BIS, as changes in entropy occur earlier than changes in the BIS.

Effectiveness of trans-nasal humidified rapid insufflation ventilatory exchange compared with standard facemask oxygenation for pre- and apneic oxygenation during anesthesia induction: A meta-analysis based on randomized controlled trials.

To further identify the effectiveness of trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) for pre- and apneic oxygenation during the anesthesia induction by comparison to facemask ventilation (FMV) based on current available evidence. Medline, EMBASE, Web of Science, Cochrane Library and CNKI databases were searched from inception to December 22, 2023 for available randomized controlled trials (RCTs). Primary outcomes were PaO2 and PaCO2 after intubation and safe apnoea time. Secondary outcomes included the O2 desaturation, end expiratory carbon dioxide (EtCO2) and complications. The effect measures for continuous and categorical outcomes were separately the mean difference (MD) and relative risk (RR) with 95% confidence interval. Twelve RCTs with 403 patients in the THRIVE group and 401 patients in th FMV group were included. Pooled results demonstrated that the PaO2 after intubation was significantly higher (MD = 82.90mmHg, 95% CI: 12.25~153.54mmHg, P = 0.02) and safe apnoea time (MD = 103.81s, 95% CI: 42.07~165.56s, P = 0.001) was longer in the THRIVE group. Besides, the incidence rate of O2 desaturation (RR = 0.28, 95% CI: 0.12-0.66, P = 0.004) and gastric insufflation (RR = 0.26, 95% CI: 0.13-0.49, P<0.001) was significantly lower in the THRIVE group. Based on current evidence, THRIVE manifested better effectiveness representing as improved oxygenation, prolonged safe apnoea time and decreased risk of complications compared to standard FMV in surgical patients. Therefore, THRIVE could be served as a novel and valuable oxygenation technology for patients during anesthesia induction.

Relationship of Intraoperative SpO2 and ETCO2 Values with Postoperative Hypoxemia in Elderly Patients after Non-Cardiac Surgery.

Elderly patients are at higher risk of postoperative hypoxemia due to their decreased respiratory function. The aim of this study was to investigate the relationship of intraoperative oxygen saturation (SpO2) and end-expiratory carbon dioxide (ETCO2) values with postoperative hypoxemia in elderly patients. The inclusion criteria were: 1) patients aged≥75 years; 2) underwent general anesthesia in non-cardiac surgery; 3) operative time longer than two hours; and 4) admission to the intensive care unit (ICU) following surgery performed between January and December 2019. Intraoperative SpO2 and ETCO2 values were collected every minute for the first two hours during surgery. The 253 patients were divided into two groups: SpO2≥92% and SpO2<92%. The time-weighted averages of intraoperative SpO2 and ETCO2 were used to compare differences between the two groups. The incidence of postoperative hypoxemia was 22.5%. For similar ventilator settings, patients with postoperative hypoxemia had lower intraoperative SpO2 and higher ETCO2 values. Sex, ASA classification, and intraoperative SpO2 were independent risk factors for postoperative hypoxemia. In conclusion, postoperative SpO2<92% was a frequent occurrence (> 20%) in elderly patients who underwent major non-cardiac surgery. Postoperative hypoxemia was associated with low intraoperative SpO2 and relatively higher ETCO2.

Effect of trans-nasal humidified rapid insufflation ventilatory exchange on reflux and microaspiration in patients undergoing laparoscopic cholecystectomy during induction of general anesthesia: a randomized controlled trial.

Reflux aspiration is a rare but serious complication during induction of anesthesia. The primary aim of this study is to compare the incidence of reflux and microaspiration in patients undergoing laparoscopic cholecystectomy during induction of general anesthesia using either a facemask or trans-nasal humidified rapid insufflation ventilatory exchange. We conducted a single-center, randomized, controlled trial. Thirty patients were allocated to either a facemask or a trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) group. Pre-oxygenation for 5 min with a facemask or THRIVE, positive pressure ventilation for 2 min or THRIVE for 2 min after anesthesia induction was followed. Before endotracheal intubation, the secretion above and below the glottis was collected to measure pepsin content and analyze blood gas. The ELISA assay for supra- and subglottic human pepsin content was used to detect the presence of reflux and microaspiration. The primary outcome was the incidence of reflux and microaspiration. Secondary outcomes were apnea time, PaO2 before tracheal intubation, and the end-expiratory carbon dioxide partial pressure. Patients in the THRIVE group had a significantly longer apnea time (379.55 ± 94.12 s) compared to patients in the facemask group (172.96 ± 58.87 s; p < 0.001). There were no differences observed in PaO2 between the groups. A significant difference in gastric insufflation, reflux, and microaspiration was observed between the groups. Gastric insufflation was 6.9% in the THRIVE group vs. 28.57% kPa in the facemask group (p = 0.041); reflux was 10.34% in the THRIVE group vs. 32.14% kPa in the facemask group (p = 0.044); and microaspiration was 0% in the THRIVE group vs. 17.86% kPa in the facemask group (p = 0.023). The application of THRIVE during induction of general anesthesia reduced the incidence of reflux and microaspiration while ensuring oxygenation and prolonged apnea time in laparoscopic cholecystectomy patients. THRIVE may be an optimal way to administer oxygen during the induction of general anesthesia in laparoscopic cholecystectomy patients. Chinese Clinical Trial Registry, No: ChiCTR2100054086, https://www.chictr.org.cn/indexEN.html.

Breathing pattern and pulmonary gas exchange in elderly patients with and without left ventricular dysfunction-modification with exercise-based cardiac rehabilitation and prognostic value.

Inefficient ventilation is an established prognostic marker in patients with heart failure. It is not known whether inefficient ventilation is also linked to poor prognosis in patients with left ventricular dysfunction (LVD) but without overt heart failure. To investigate whether inefficient ventilation in elderly patients with LVD is more common than in patients without LVD, whether it improves with exercise-based cardiac rehabilitation (exCR), and whether it is associated with major adverse cardiovascular events (MACE). In this large multicentre observational longitudinal study, patients aged ≥65 years with acute or chronic coronary syndromes (ACS, CCS) without cardiac surgery who participated in a study on the effectiveness of exCR in seven European countries were included. Cardiopulmonary exercise testing (CPET) was performed before, at the termination of exCR, and at 12 months follow-up. Ventilation (VE), breathing frequency (BF), tidal volume (VT), and end-expiratory carbon dioxide pressure (PETCO2) were measured at rest, at the first ventilatory threshold, and at peak exercise. Ventilatory parameters were compared between patients with and without LVD (based on cardio-echography) and related to MACE at 12 month follow-up. In 818 patients, age was 72.5 ± 5.4 years, 21.9% were women, 79.8% had ACS, and 151 (18%) had LVD. Compared to noLVD, in LVD resting VE was increased by 8%, resting BF by 6%, peak VE, peak VT, and peak PETCO2 reduced by 6%, 8%, and 5%, respectively, and VE/VCO2 slope increased by 11%. From before to after exCR, resting VE decreased and peak PETCO2 increased significantly more in patients with compared to without LVD. In LVD, higher resting BF, higher nadir VE/VCO2, and lower peak PETCO2 at baseline were associated with MACE. Similarly to patients with HF, in elderly patients with ischemic LVD, inefficient resting and exercise ventilation was associated with worse outcomes, and ExCR alleviated abnormal breathing patterns and gas exchange parameters.

Laparoscopic management of ovarian cysts during pregnancy under urgent situations.

Majority of adnexal masses are incidental findings during pregnancy and resolve spontaneously. They may complicate pregnancy due to haemorrhage, cyst rupture and ovarian torsion. Laparoscopy is the preferred surgical intervention owing to shorter operative time, quicker recovery and lower post-operative pain. However, safety and feasibility of laparoscopic surgery in the management of ovarian cysts in pregnant women is challenging especially at advanced gestational ages and in urgent situations. In this retrospective study, a total of 48 cases of urgent laparoscopic surgeries were evaluated in the first and second trimesters of pregnancy between March 2018 and March 2021 in Al-Zahra Hospital, Tabriz, Iran. The operations were ended in all patients successfully. The mean operation time was 45 min. There were no foetal maternal complications. All pregnancies had been terminated after 37 weeks of gestation. Oophorectomy had been performed in six patients and six other patients needed blood transfusion. Ovarian torsion was the most common reason for emergency surgery and mature teratoma was the most commonly reported pathology. Tocolytic therapy was required in six patients, and all of the patients were prescribed 50 mg of injectable progesterone twice daily for 10 days after surgery. The mean intra-abdominal pressure was equal to 15 mmHg and the mean end-expiratory carbon dioxide (CO 2 ) pressure was 36 mmHg. Intravenous paracetamol was used to relieve post-operative pain. The mean hospitalisation time was 1.63 days. Most of the ovarian cysts can be managed laparoscopically with ensured safety and lower morbidity even in emergency situations at advanced gestational ages.

Metabolic and ventilatory changes during postural change from the supine position to the reclining position in bedridden older patients.

The prevention of pneumonia in bedridden older patients is important, and its recurrence in these patients is a relevant issue. Patients who are bedridden and inactive, and have dysphagia are considered to be at risk for pneumonia. Efforts to reduce the bedridden state and low activity may be necessary to reduce the risk of developing pneumonia in bedridden older patients. This study aimed to clarify the effects of postural change from the supine position to the reclining position on metabolic and ventilatory parameters and on safety in bedridden older patients. Using a breath gas analyzer and other tools, we assessed the following 3 positions: lying on the back (supine), resting in the Fowler position (Fowler), and resting in an 80° recline wheelchair (80°). Measurements were oxygen uptake, carbon dioxide output, gas exchange ratio, tidal volume (VT), minute volume, respiratory rate, inspiratory time, expiratory time, total respiratory time, mean inspiratory flow, metabolic equivalents, end-expiratory oxygen, and end-expiratory carbon dioxide as well as various vital signs. The study analysis included 19 bedridden participants. The change in oxygen uptake driven by changing the posture from the supine position to the Fowler position was as small as 10.8 mL/minute. VT significantly increased from the supine position (398.4 ± 111.2 mL) to the Fowler position (426.9 ± 106.8 mL) (P = .037) and then showed a decreasing trend in the 80° position (416.8 ± 92.5 mL). For bedridden older patients, sitting in a wheelchair is a very low-impact physical activity, similar to that in normal people. The VT of bedridden older patients was maximal in the Fowler position, and the ventilatory volume did not increase with an increasing reclining angle, unlike that in normal people. These findings suggest that appropriate reclining postures in clinical situations can promote an increase in the ventilatory rate in bedridden older patients.

Comparison between automated cardiopulmonary resuscitation and manual cardiopulmonary resuscitation in the rescue of cardiac and respiratory arrest.

To compare the efficacy of automated cardiopulmonary resuscitation (A-CPR) and manual cardiopulmonary resuscitation (M-CPR) in the rescue of cardiac and respiratory arrest. A retrospective, single-center observational study was conducted to identify 106 patients by reviewing medical records of 269 patients with cardiac and respiratory arrest treated in The Second Hospital of Hebei Medical University, Shandong Provincial Third Hospital (Jinan, China) from February 2019 to February 2021. Patients were divided into A-CPR group (n = 55) and M-CPR group (n = 51) based on the resuscitation treatment method. The groups were matched for age, gender and the cause of cardiac arrest. Rescue effects, blood gas analysis indicators, respiratory dynamics and condition improvement of the two groups were compared. In terms of rescue effects, return of spontaneous circulation (ROSC) rate, successful rate of cardiopulmonary resuscitation (CPR), 24-hour survival rate and survival discharge rate in the A-CPR group were higher than M-CPR group (P<0.05). With respect to blood gas analysis indicators and respiratory dynamics, the partial pressure of carbon dioxide (PaCO2) in the A-CPR group was lower than M-CPR group at 15 and 30 minutes after CPR, while the partial pressure of oxygen (PaO2), blood oxygen saturation (SaO2), end expiratory carbon dioxide (PetCO2), coronary perfusion pressure (CPP) and mean arterial pressure (MAP) in the A-CPR group were higher than M-CPR group (P<0.05). In aspect of condition improvement, spontaneous breathing, heart rate, spontaneous circulation, blood pressure recovery time and CPR time in the A-CPR group were shorter than M-CPR group (P<0.05). The application effect of A-CPR in the rescue of cardiac and respiratory arrest, the improvement of blood gas analysis indexes, respiration and condition improvement are more significant than M-CPR.

Breathing patterns and ventilatory efficiency in elderly cardiac patients with and without left ventricular dysfunction before and after exercise-based cardiac rehabilitation: the EU-CaRE study

Abstract Introduction Coronary artery disease (CAD) may progress to left ventricular dysfunction (LVD) and chronic heart failure. A reduced ventilatory efficiency in these patients is associated with worse outcome. However, breathing patterns at rest and during exercise and their change during exercise-based cardiac rehabilitation (exCR) have been poorly described in this population. We aimed to analyse respiratory and gas-exchange parameters in elderly patients with CAD included in a multicentre study on effectiveness of exCR across seven European countries (EU-CaRE). Methods Patients aged 65 years and older with acute (ACS) and chronic coronary syndromes (CCS) who participated in exCR were included. Cardiopulmonary exercise testing (CPET) was performed before (T0) and at termination of exCR (T1), and 12 months after start of exCR (T2). Ventilation (VE), breathing frequency (BF), and end-expiratory carbon dioxide pressure (PetCO2) were measured at rest, at first ventilatory threshold and peak exercise. Ventilatory efficiency, expressed as VE/VCO2 slope and the nadir of VE/VCO2 ratio were measured during the ramp test. Peak oxygen uptake was averaged over 30 s. Breathing parameters over time were compared between patients without and with left ventricular dysfunction (LVD, defined as LV ejection fraction &amp;lt;45%) by mixed linear models corrected for age, sex and body mass index. Results 818 out of 1633 patients of the EU-CaRE study fulfilled inclusion criteria, 151 (18%) had LVD, of these, 86% were in New York Heart Association (NYHA) functional class I. Mean age was 72.5±5.4 years, 21.9% were women, and 79.8% had acute ACS. Compared to patients without LVD, in patients with LVD resting VE was increased 9%, VE/VCO2 slope 14%, and nadir VE/VCO2 ratio 9%, while PetCO2 was reduced at rest and peak exercise by 6%. From before to after exCR, resting ventilation and breathing frequency, as well as VE/VCO2 slope and nadir VE/VCO2 during exercise decreased significantly more in patients with LVD compared to patients without, while improvement in peak oxygen uptake was similar (Figure 1). Conclusions In contrast to their own perception based on NYHA class, patients with LVD had exaggerated breathing at rest and as response to exercise with consistently reduced PetCO2 and ventilatory efficiency. Abnormal breathing patterns may be an early and clinically relevant sign of LVD and linked to increased chemosensitivity and/or abnormal ergoreflex. Exercise-based CR may contribute to improvements of breathing patterns and ventilator efficiency in this population. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union's Horizon 2020 research and innovation program and Swiss State Secretariat for Education, Research and Innovation for the Swiss consortium partner

Anesthesia personnel’s visual attention regarding patient monitoring in simulated non-critical and critical situations, an eye-tracking study

BackgroundCognitive ergonomics design of patient monitoring may reduce human factor errors in high-stress environments. Eye-tracking is a suitable tool to gain insight into the distribution of visual attention of healthcare professionals with patient monitors, which may facilitate their further development.MethodsThis prospective, exploratory, high-fidelity simulation study compared anesthesia personnel’s visual attention (fixation count and dwell-time) to 15 areas of interest on the patient monitor during non-critical and critical anesthesia situations. Furthermore, we examined the extent to which participants’ experience influenced visual attention and which vital signs displayed on the patient monitor received the most visual attention. We used mixed zero-inflated Poisson regression and mixed linear models to analyze the data.ResultsAnalyzing 23 ten-minute scenarios, we found significantly more fixations to the areas of interest on the patient monitor during critical than non-critical situations (rate ratio of 1.45; 95% CI 1.33 to 1.59; p < 0.001). However, the dwell-time on the areas of interest did not significantly differ between the non-critical and critical situations (coefficient of − 1.667; 95% CI − 4.549 to 1.229; p = 0.27). The professional experience did not significantly influence the visual attention (fixation: rate ratio of 0.88; 95% CI 0.54 to 1.43; p = 0.61 and dwell-time: coefficient of 0.889; 95% CI − 1.465 to 3.229; p = 0.27).Over all situations, anesthesia personnel paid the most attention to the vital signs blood pressure (fixation: mean [SD] of 108 [74.83]; dwell-time: mean [SD] of 27 [15.90] seconds), end-expiratory carbon dioxide (fixation: mean [SD] of 59 [47.39]; dwell-time: mean [SD] of 30 [21.51] seconds), and the electrocardiogram (fixation: mean [SD] of 58 [64.70]; dwell-time: mean [SD] of 15 [14.95] seconds).ConclusionsCritical anesthesia situations increased anesthesia personnel’s visual interaction with the patient monitor. Furthermore, we found that their visual attention focused mainly on a few vital signs. To assist clinicians in critical situations, manufacturers should optimize monitors to convey necessary information as easily and quickly as possible and optimize the visibility of less frequently observed but equally critical vital signs, especially when they are in an abnormal range.

Comparison of the effectiveness of high-flow nasal oxygen vs. standard facemask oxygenation for pre- and apneic oxygenation during anesthesia induction: a systematic review and meta-analysis

BackgroundIn recent years, high flow nasal oxygen (HFNO) has been widely used in clinic, especially in perioperative period. Many studies have discussed the role of HFNO in pre- and apneic oxygenation, but their results are controversial. Our study aimed to examine the effectiveness of HFNO in pre- and apneic oxygenation by a meta-analysis of RCTs.MethodsEMBASE, PUBMED, and COCHRANE LIBRARY databases were searched from inception to July 2021 for relevant randomized controlled trails (RCTs) on the effectiveness of HFNO versus standard facemask ventilation (FMV) in pre- and apenic oxygenation. Studies involving one of the following six indicators: (1) Arterial oxygen partial pressure (PaO2), (2) End expiratory oxygen concentration (EtO2), (3) Safe apnoea time, (4) Minimum pulse oxygen saturation (SpO2min), (5) Oxygenation (O2) desaturation, (6) End expiratory carbon dioxide (EtCO2) or Arterial carbon dioxide partial pressure(PaCO2) were included. Due to the source of clinical heterogeneity in the observed indicators in this study, we adopt random-effects model for analysis, and express it as the mean difference (MD) or risk ratio (RR) with a confidence interval of 95% (95%CI). We conducted a risk assessment of bias for eligible studies and assessed the overall quality of evidence for each outcome.ResultsFourteen RCTs and 1012 participants were finally included. We found the PaO2 was higher in HFNO group than FMV group with a MD (95% CI) of 57.38 mmHg (25.65 to 89.10; p = 0.0004) after preoxygenation and the safe apnoea time was significantly longer with a MD (95% CI) of 86.93 s (44.35 to 129.51; p < 0.0001) during anesthesia induction. There were no significant statistical difference in the minimum SpO2, CO2 accumulation, EtO2 and O2 desaturation rate during anesthesia induction between the two groups.ConclusionsThis systematic review and meta-analysis suggests that HFNO should be considered as an oxygenation tool for patients during anesthesia induction. Compared with FMV, continuous use of HFNO during anesthesia induction can significantly improve oxygenation and prolong safe apnoea time in surgical patients.

Application of high frequency jet ventilation system in laryngopharyngeal and tracheal surgery

Objective:The effectiveness and safety of high frequency ventilation system in laryngopharyngeal and tracheal surgery is discussed. Methods:According to The American Society of Anesthesiologists Ⅰ-Ⅱ level, 60 cases of selective throat and tracheal surgery undering general anesthesia were randomly divided into high frequency jet ventilation group （group HFJV） and intermittent positive pressure ventilation group （IPPV group）, with 30 cases in each group. Group HFJV was treated with HFJV and group IPPV with a small caliber endotracheal tube connected to an anesthesia machine was treated with IPPV.Before anesthesia （T0）, after the success of the laryngoscope placed （T1）, 5 minites after ventilation （T2） and 5 minites after the laryngoscope removed （T3）, hemodynamic parameters were recorded at each time point , in T0, T2 and T3 record , arterial blood gas index, the patient's airway pressure, end-expiratory carbon dioxide concentration, surgical field quality and total blood loss, operating time and awakening time were recorded and compared between the two groups. Results:The average airway pressure and intraoperative average total blood loss of group HFJV were significantly lower than that of group IPPV（P<0.01）, and the average operative field quality of group HFJV was significantly better（P<0.01）, but there was no statistical significance in the effects on hemodynamics, arterial blood gas and other indicators compared with group IPPV（P>0.05）. No serious adverse events occurred in 2 groups. Conclusion:HFJV system can be used effectively in laryngopharyngeal and tracheal surgery, reducing intraoperative blood loss and improving surgical field of vision without obvious adverse reactions.

Relationship between end-tidal carbon dioxide and arterial carbon dioxide in critically ill patients on mechanical ventilation: A cross-sectional study.

So far, only a few studies have examined and confirmed the correlation between end-expiratory carbon dioxide partial pressure (PETCO2) and arterial carbon dioxide tension (PaCO2) during invasive mechanical ventilation in critically ill patients. This study aimed to observe the correlation between PaCO2 and PETCO2 in patients on invasive mechanical ventilation.This was a cross-sectional study of adult patients on invasive mechanical ventilation enrolled between June 2018 and March 2019. Patients requiring invasive mechanical ventilation underwent one of the following mechanical ventilation modes: assisted/controlled ventilation, synchronized intermittent mandatory ventilation, and spontaneous breathing. Subsequently, the difference and correlation between PETCO2 and PaCO2 were analyzed.A total of 184 patients with 298 pairs of PETCO2-PaCO2 data were included in the analysis. Without distinguishing the ventilator mode, there was significant positive correlation between PETCO2 and PaCO2. In different ventilator modes, the correlation coefficient was 0.81 for synchronized intermittent mandatory ventilation, 0.47 for assisted/controlled ventilation, and 0.55 for spontaneous breathing, respectively. In patients with chronic obstructive pulmonary disease (r = 0.80), multiple trauma (r = 0.64), severe pneumonia (r = 0.60), gastrointestinal surgery (r = 0.57), and cerebrovascular diseases (r = 0.53), PETCO2 and PaCO2 were positively correlated. For oxygenation index <200 mm Hg, correlation coefficient r = 0.69, P < .001; oxygenation index ≥200, r = 0.73, P < .001. Under different oxygenation indexes, there was no statistically significant difference between the 2 correlation coefficients. Among 116 pairs of data with oxygenation index <200 mm Hg, the difference of PaCO2-PETCO2 ≥10 mm Hg was found in 25 pairs (21.55%); in 182 pairs of data with oxygenation index ≥200 mm Hg, the difference of PaCO2-PETCO2 ≥10 mm Hg was found in 26 pairsIn patients on invasive mechanical ventilation, there was a good correlation between PETCO2 and PaCO2 in different ventilator modes, different disease types, and different oxygenation indexes, especially in synchronized intermittent mandatory ventilation mode and chronic obstructive pulmonary disease patients.

Neuromuscular blockade with atracurium for ophthalmic surgery in horses-Effects on surgical and anesthetic characteristics and recovery quality.

To study the surgical, anesthetic and recovery qualities of horses receiving either a neuromuscular blocking agent (atracurium) or intravenous lidocaine (treatment groups A and L, respectively). A total of thirty horses presented for ocular surgery were used in this study. Horses were randomly assigned to receive either atracurium (group A) or a lidocaine constant rate infusion (group L). Surgical quality was graded on a scale from 1 (excellent)-5 (poor). While anesthetized, the heart rate, oxygen saturation and mean arterial blood pressure, and end-expiratory carbon dioxide and desflurane concentration were monitored and recorded every 5minutes. Recovery was scored on a scale from 10 (best)-115 (worst). Horses in treatment group A needed significantly less desflurane then horses in treatment group L (p=0.04). Horses in treatment group A had a significantly better surgery score of 1 (1-2) (median and range) then horses in treatment group L (2.5; 1-5) (p=0.02). The quality of recovery was significantly better in horses in treatment group A compared with treatment group L, and horses needed significantly less time to reach the standing position. Atracurium and lidocaine CRI are safe methods of anesthesia for equine patients undergoing ocular surgery. Horses receiving atracurium needed less desflurane and had better surgery and recovery scores than horses receiving a lidocaine constant rate infusion.

Risk Factors for the Development of Intraoperative Hypoxia in Patients Undergoing Nonintubated Video-Assisted Thoracic Surgery: A Retrospective Study from a Single Center.

BackgroundNonintubated video-assisted thoracic surgery (NIVATS) has been demonstrated to be safe and effective in patients. However, the risk factors for intraoperative hypoxia are unclear. This retrospective study aimed to identify the risk factors for the development of intraoperative hypoxia in patients undergoing NIVATS.Material/MethodsThe study included patients who underwent NIVATS between January 2011 and December 2018. Intraoperative hypoxia was defined as SpO2 ≤93%. Risk factors for hypoxia were identified by binary logistic regression analysis, and the characteristic distribution of patients with and without hypoxia was elaborated.ResultsOf 2742 included patients, age, anesthesia method, the technical level of surgeons, stair-climbing ability, and type of thoracic procedure were associated with intraoperative hypoxia (P<0.05). The characteristics of patients with hypoxia were older age (P=0.011), higher body mass index and revised cardiac risk index level (P=0.033 and P=0.031), and lower composition of stair-climbing ≥22 m (P<0.001). These patients also had more anatomical lung surgery and mediastinal mass resection (P=0.033) and more epidural anesthesia (P=0.005). The surgeries were more likely to be performed by surgeons with less than 10 years of VATS training (P=0.009) and to have increased intraoperative maximum end-expiratory carbon dioxide partial pressure (P<0.001). These patients had a longer Intensive Care Unit stay (P<0.001), duration of chest-tube drainage (P=0.019), and postoperative hospitalization (P=0.003).ConclusionsThe current study suggests that old age and stair-climbing ability of patients, anesthesia method, thoracic procedures, and surgeon experience are risk factors for intraoperative hypoxia in patients undergoing NIVATS.

Study on Effect of Laryngeal Mask Anesthesia and Endotracheal Intubation Anesthesia on Elderly Patients Undergoing Laparoscopic Gallbladder Surgery

Objective: To analyze the effect of laryngeal mask anesthesia and endotracheal intubation anesthesia in elderly laparoscopic gallbladder surgery. Methods: 100 subjects of the experiment came from elderly patients with gallbladder stones admitted from September 2016 to September 2019 in our hospital. There were group A and group B of 50 cases each, and were used tube anesthesia and laryngeal mask anesthesia, then comparing the anesthesia effect. Results: Statistical significance(P&lt;0.05): Air pressure and end-respiratory carbon dioxide partial pressure index changes when immediately after insertion, immediately after removal, 3 minutes after removal; heart rate, mean arterial pressure, airway pressure, and end-expiratory carbon dioxide index changes when 3 minutes after insertion and immediately before removal; blood glucose and cortisol changes when after insertion, immediately before removal and min after removal. No statistical significance(P&gt;0.05): Changes in heart rate, mean arterial pressure, airway pressure, and end-expiratory carbon dioxide indexes before insertion; changes in blood glucose and cortisol indexes before insertion. Conclusion: It is more ideal for elderly patients with abdominal cavity and gallbladder surgery to have laryngeal mask anesthesia, which can effectively keep blood circulation stable and have promotion value.

Contributions of residual hypoxemia to exercise hyperventilation in Fontan patients.

ABSTRACTIt is unsettled whether increased exercise ventilation in Fontan subjects is due to increased pulmonary dead space or augmented ventilatory drive. Twenty-six Fontan patients underwent symptom-limited treadmill cardiopulmonary exercise testing. Two groups of age- and sex- matched subjects served as controls: the biventricularly repaired (Bi, n = 18), and the “true” control (C, n = 29) groups. Peak oxygen uptake (V̇O2peak) was not different among groups (41.0 +/– 8.4 ml/min/kg, 43.5 +/– 6.6 ml/min/kg, and 45.9 +/– 11.6 ml/min/kg for Fontan, Bi, and C groups, respectively, p = 0.16). Fontan subjects, however, showed steeper alveolar ventilation/carbon-dioxide (V̇A/V̇CO2) regression slope (35.5 +/– 5.3, 28.7 +/– 3.8, and 29.5 +/– 3.0 l/ml, for Fontan, Bi, and C groups, respectively, p<0.0001), and lower end-expiratory carbon-dioxide fraction (FetCO2VAT) at ventilatory threshold (VAT) (4.4 +/– 0.5%, 5.5 +/– 0.5%, and 5.5 +/– 0.4%, for Fontan, Bi, and C groups, respectively, p<0.001). The dead-space ventilation fraction at VAT was similar among groups (0.33 +/– 0.06, 0.33 +/– 0.04, 0.35 +/– 0.05 for Fontan, Bi, and C groups, respectively, p = 0.54). In Fontan subjects, arterial oxygen saturation at rest (SaO2rest) was correlated with V̇A/V̇CO2 regression slope (r = –0.41, p = 0.04) and with FetCO2VAT (p = –0.53, p<0.01). We conclude that Fontan patients show exercise hyperventilation due to augmented central and/or peripheral ventilatory drive, which is further augmented by residual hypoxemia.

Opioid Sensitivity in Children with and without Obstructive Sleep Apnea.

Opioids are a mainstay of perioperative analgesia. Opioid use in children with obstructive sleep apnea is challenging because of assumptions for increased opioid sensitivity and assumed risk for opioid-induced respiratory depression compared to children without obstructive sleep apnea. These assumptions have not been rigorously tested. This investigation tested the hypothesis that children with obstructive sleep apnea have an increased pharmacodynamic sensitivity to the miotic and respiratory depressant effects of the prototypic μ-opioid agonist remifentanil. Children (8 to 14 yr) with or without obstructive sleep apnea were administered a 15-min, fixed-rate remifentanil infusion (0.05, 0.1, or 0.15 μg · kg · min). Each dose group had five patients with and five without obstructive sleep apnea. Plasma remifentanil concentrations were measured by tandem liquid chromatography mass spectrometry. Remifentanil effects were measured via miosis, respiratory rate, and end-expired carbon dioxide. Remifentanil pharmacodynamics (miosis vs. plasma concentration) were compared in children with or without obstructive sleep apnea. Remifentanil administration resulted in miosis in both non-obstructive sleep apnea and obstructive sleep apnea patients. No differences in the relationship between remifentanil concentration and miosis were seen between the two groups at any of the doses administered. The administered dose of remifentanil did not affect respiratory rate or end-expired carbon dioxide in either group. No differences in the remifentanil concentration-miosis relation were seen in children with or without obstructive sleep apnea. The dose and duration of remifentanil administered did not alter ventilatory parameters in either group.

The relationship between end-expired carbon dioxide tension and severity of venous air embolism during sitting neurosurgical procedures – A contemporary analysis

Determine if changes in expired carbon dioxide tension correlate with the severity of venous air embolism (VAE) associated hemodynamic changes in humans. Retrospective case series. A single academic medical center with high-volume neurosurgical practice. One hundred forty seven adult patients having neurosurgical procedures performed with general anesthesia in the sitting position who experienced venous air embolism. Identification of documentation of venous air embolism by either precordial Doppler sonography or transesophageal echocardiography. Retrospective determination of changes in end-expired carbon dioxide (EECO2) changes associated with venous air embolism. Greater absolute and relative decreases in end-expired carbon dioxide tension were associated with greater hemodynamic manifestations of venous air embolism. However, based on receiver operating characteristic curve analysis, the absolute and relative changes in EECO2 have moderate utility for predicting the severity of hemodynamic consequences of venous air embolism as area under the curve for absolute and relative carbon dioxide tensions were 0.7654 and 0.7263, respectively. Greater magnitude of decreases in EECO2 is associated with hemodynamically-significant VAE in mechanically-ventilated patients. However, the magnitude of changes may have limited utility to diagnose VAE or exclude the diagnosis of VAE in patients with unexplained intraoperative hypotension.

Alfaxalone for maintenance of anaesthesia in ponies undergoing field castration: continuous infusion compared with intravenous boluses

To compare alfaxalone as continuous intravenous (IV) infusion with intermittent IV injections for maintenance of anaesthesia in ponies undergoing castration. Prospective, randomized, 'blinded' clinical study. A group of 33 entire male Welsh ponies undergoing field castration. After preanaesthetic medication with IV detomidine (10μgkg-1) and butorphanol (0.05mgkg-1), anaesthesia was induced with IV diazepam (0.05mgkg-1) followed by alfaxalone (1mgkg-1). After random allocation, anaesthesia was maintained with either IV alfaxalone 2mgkg-1hour-1 (group A; n=16) or saline administered at equal volume (group S; n=17). When necessary, additional alfaxalone (0.2mgkg-1) was administered IV. Ponies were breathing room air. Using simple descriptive scales, surgical conditions and anaesthesia recovery were scored. Total amount of alfaxalone, ponies requiring additional alfaxalone and time to administration, time from induction to end of infusion and end of infusion to standing were noted. Indirect arterial blood pressure, pulse and respiratory rates, end-expiratory carbon dioxide partial pressure and arterial haemoglobin oxygen saturation were recorded every 5 minutes. Data were analysed using Student t, Mann-Whitney U and chi-square tests, where appropriate (p<0.05). Total amount of alfaxalone administered after induction of anaesthesia (0.75±0.27 versus 0.17±0.23mgkg-1; p<0.0001) and time to standing (14.8±4 versus 11.6±4 minutes; p=0.044) were higher in group A compared to group S. Ponies requiring additional alfaxalone boluses [four (group A) versus seven (group S)] and other measured variables were similar between groups; five ponies required oxygen supplementation [three (group A) versus two (group S)]. Continuous IV infusion and intermittent administration of alfaxalone provided similar anaesthesia quality and surgical conditions in ponies undergoing field castration. Less alfaxalone is required when used intermittently.