Effect of a non-reactive absorbent with or without environmentally oriented electronic feedback on anesthesia provider's fresh gas flow rates: A greening initiative

STUDY OBJECTIVE

To examine the effects of a non-reactive carbon dioxide absorbent (AMSORB® Plus) versus a traditional carbon dioxide absorbent (Medisorb™) on the FGF used by anesthesia providers and an electronic educational feedback intervention using Carestation™ Insights (GE HealthCare) on provider-specific change in FGF.

DESIGN

Prospective, single-center cohort study set in a greening initiative.

SETTING

Operating room.

PARTICIPANTS

157 anesthesia providers (i.e., anesthesiology trainees, certified registered nurse anesthetists, and solo anesthesiologists).

INTERVENTIONS

Intervention #1 was the introduction of AMSORB® Plus into 8 Aisys CS2, Carestation™ Insights-enabled anesthesia machines (GE HealthCare) at the study site. At the end of week 6, anesthesia providers were educated and given an environmentally oriented electronic feedback strategy for the next 12 weeks of the study (Intervention #2) using Carestation™ Insights data.

MEASUREMENTS

The dual primary outcomes were the difference in average daily FGF during maintenance anesthesia between machines assigned to AMSORB® Plus versus Medisorb™ and the provider-specific change in average fresh gas flows after 12 weeks of feedback and education compared to the historical data.

MAIN RESULTS

Over the 18-week period, there were 1577 inhaled anesthetics performed in the 8 operating rooms (528 for intervention 1, 1049 for intervention 2). There were 1001 provider days using Aisys CS2 machines and 7452 provider days of historical data from the preceding year. Overall, AMSORB® Plus was not associated with significantly less FGF (mean - 80 ml/min, 97.5% confidence interval - 206 to 46, P = .15). The environmentally oriented electronic feedback intervention was not associated with a significant decrease in provider-specific mean FGF (-112 ml/min, 97.5% confidence interval - 244 to 21, P = .059).

CONCLUSIONS

This study showed that introducing a non-reactive absorbent did not significantly alter FGF. Using environmentally oriented electronic feedback relying on data analytics did not result in significantly reduced provider-specific FGF.

Nasal cannula and face mask gas flow rates when connecting to the Y-piece of the anesthesia circuit

STUDY OBJECTIVE

To determine the relationship between the delivered gas flows via nasal cannulas and face masks and the set gas flow and the breathing circuit pressure when connecting to the Y-adapter of the anesthesia breathing circuit and using the oxygen blender on the anesthesia machine, relevant to surgery when there is concern for causing a fire. The flow rates that are delivered at various flow rates and circuit pressures have not been previously studied.

DESIGN

Laboratory investigation.

SETTING

Academic medical center.

PATIENTS

None.

INTERVENTIONS

The gas flows from each of 3 anesthesia machines from the same manufacturer were systematically increased from 1 to 15 L/min with changes to the adjustable pressure limiting valve to maintain 0-40 cm water pressure in the breathing circuit for nasal cannula testing and at 20-30 cm water circuit pressure for face masks.

MEASUREMENTS

The delivered gas flows to the cannula were determined using a float-ball flowmeter for combinations of set gas flows and circuit pressures after connecting the cannula tubing to the Y-piece of the anesthesia circuit via a tracheal tube adapter. Decreasing the supply tubing length on the delivered flow rates was evaluated.

MAIN RESULTS

There was a highly linear relationship between the anesthesia circuit pressure and the delivered nasal cannula flow rates, with 0 flow observed when the APL valve was fully open (i.e., 0 cm water). However, even under maximum conditions (40 cm water and 15 L/min), the delivered nasal cannula flow rate was 3.5 L/min. Shortening the 6.5-ft cannula tubing increased the flow at 20 and 30 cm water by approximately 0.12 L/min/ft. The estimated FiO2 assuming a minute ventilation of 5 L/min and 30% FiO2 ranged from 21.7% to 27.0% at nasal cannula flow rates of 0.5 to 4.0 L/min. When using a face mask and the APL fully closed, delivered flow rates were 0.25 L/min less than the set flow rate between 1 and 3 L/min and equal to the set flow rate between 4 and 8 L/min.

CONCLUSIONS

When using a nasal cannula adapted to the Y-piece of the anesthesia circuit, the delivery system is linearly dependent on the pressure in the circuit and uninfluenced by the flow rate set on the anesthesia machine. However, only modest flow rates (≤ 3.5 L/min) and a limited increase in the inspired FiO2 are possible when using this delivery method. When using a face mask and the anesthesia circuit, flow rates close to the set flow rate are possible with the APL valve fully closed. Patients scheduled for sedation for head and neck procedures with increased fire risk who require more than a marginal increase in the FiO2 to maintain an acceptable pulse oximetry saturation may need general anesthesia with tracheal intubation.

Carbon Footprint of Total Intravenous and Inhalation Anesthesia in the Transcatheter Aortic Valve Replacement Procedure

OBJECTIVES

To quantify and compare the emissions for deep sedation with total intravenous anesthesia (TIVA) and general anesthesia with inhaled agents during the transcatheter aortic valve replacement procedure.

DESIGN

A retrospective study.

SETTING

A tertiary hospital in Boston, Massachusetts.

PARTICIPANTS

The anesthesia records of 604 consecutive patients who underwent the transcatheter aortic valve replacement procedure between January 1, 2018, and March 31, 2022, were reviewed and analyzed.

INTERVENTIONS

Data were examined and compared in the following 2 groups: general anesthesia with inhaled agents and deep sedation with TIVA.

MEASUREMENTS AND MAIN RESULTS

The gases, drugs, airway management devices, and anesthesia machine electricity were collected and converted into carbon dioxide emissions (CO2e). The carbon emissions of intravenous medications were converted with the CO2e data for anesthetic pharmaceuticals from the Parvatker et al. study. For inhaled agents, inhaled anesthetics and oxygen/air flow rate were collected at 15-minute intervals and calculated using the anesthetic gases calculator provided by the Association of Anesthetists. The airway management devices were converted based on life-cycle assessments. The electricity consumed by the anesthesia machine during general anesthesia was estimated from the manufacturer's data (Dräger, GE) and local Energy Information Administration data. The data were analyzed in the chi-squared test or Wilcoxon rank-sum test. There were no significant differences in the patients' demographic characteristics, such as age, sex, weight, height, and body mass index. The patients who received general anesthesia with inhaled agents had statistically higher total CO2e per case than deep sedation with TIVA (16.188 v 1.518 kg CO2e; p < 0.001), primarily due to the inhaled agents and secondarily to airway management devices. For deep sedation with TIVA, the major contributors were intravenous medications (71.02%) and airway management devices (16.58%). A subgroup study of patients who received sevoflurane only showed the same trend with less variation.

CONCLUSIONS

The patients who received volatile anesthesia were found to have a higher CO2e per case. This difference remained after a subgroup analysis evaluating those patients only receiving sevoflurane and after accounting for the differences in the duration of anesthesia. Data from this study and others should be collectively considered as the healthcare profession aims to provide the best care possible for their patients while limiting the harm caused to the environment.

Acute Intraoperative Tympanic Membrane Rupture in Patient Anesthetized With Desflurane Without Nitrous Oxide: A Case Report

We report a case of acute intraoperative tympanic membrane (TM) rupture in a patient anesthetized with desflurane without N2O. The patient was undergoing endoscopic retrograde cholangiopancreatography (ERCP) to treat ascending cholangitis. TM rupture is known to occur with N2O but has not been reported in the literature with the use of inhaled volatile anesthetics without N2O. We suspect that several factors contributed to this complication, including prone positioning, a remote history of ear trauma, and the selection of desflurane as the maintenance anesthetic as opposed to a vapor with a higher blood-gas partition coefficient.

Impact of prognostic nutritional index change on prognosis after colorectal cancer surgery under propofol or sevoflurane anesthesia

BACKGROUND

The alteration of the prognostic nutritional index (PNI) or the utilization of distinct anesthesia strategies has been linked to the prognosis of various cancer types, but the existing evidence is limited and inconclusive, particularly for colorectal cancer (CRC). Our objective was to evaluate the association between PNI change and progression free survival (PFS) and overall survival (OS) in patients treated with CRC surgery after propofol-based or sevoflurane-based anesthesia.

METHODS

We conducted a retrospective analysis of 414 patients with CRC who underwent surgical resection. Among them, 165 patients received propofol-based total intravenous anesthesia (TIVA-P), while 249 patients received sevoflurane-based inhalation anesthesia (IA-S). The PNI change (ΔPNI) was calculated by subtracting the pre-surgery PNI from the post-surgery PNI, and patients were categorized into high (≥ -2.25) and low (< -2.25) ΔPNI groups. Univariate and multivariate analyses were employed to evaluate the effects of the two anesthesia methods, ΔPNI, and their potential interaction on PFS and OS.

RESULTS

The median duration of follow-up was 35.9 months (interquartile range: 18-60 months). The five-year OS rates were 63.0% in the TIVA-P group and 59.8% in the IA-S group (hazard ratio [HR]: 0.96; 95% confidence interval [CI]: 0.70-1.35; p = 0.864), while the five-year PFS rates were 55.8% and 51.0% (HR: 0.92; 95% CI: 0.68-1.26; p = 0.614), respectively. In comparison to patients in the low ΔPNI group, those in the high ΔPNI group exhibited a favorable association with both OS (HR: 0.57; 95% CI: 0.40-0.76; p < 0.001) and PFS (HR: 0.58; 95% CI: 0.43-0.79; p < 0.001). Stratified analysis based on ΔPNI revealed significant protective effects in the propofol-treated participants within the high ΔPNI group, whereas such effects were not observed in the low ΔPNI group, for both OS (p for interaction = 0.004) and PFS (p for interaction = 0.024).

CONCLUSIONS

Our data revealed that among patients who underwent CRC surgery, those treated with TIVA-P exhibited superior survival outcomes compared to those who received IA-S, particularly among individuals with a high degree of PNI change.

Impact of total intravenous anesthesia and total inhalation anesthesia as the anesthesia maintenance approaches on blood glucose level and postoperative complications in patients with type 2 diabetes mellitus: a double-blind, randomized controlled trial

BACKGROUND

Diabetes mellitus is a prevalent metabolic disease in the world. Previous studies have shown that anesthetics can affect perioperative blood glucose levels which related to adverse clinical outcomes. Few studies have explored the choice of general anesthetic protocol on perioperative glucose metabolism in diabetes patients. We aimed to compare total intravenous anesthesia (TIVA) with total inhalation anesthesia (TIHA) on blood glucose level and complications in type 2 diabetic patients undergoing general surgery.

METHODS

In this double-blind controlled trial, 116 type 2 diabetic patients scheduled for general surgery were randomly assigned to either the TIVA group or TIHA group (n = 56 and n = 60, respectively). The blood glucose level at different time points were measured and analyzed by the repeated-measures analysis of variance. The serum insulin and cortisol levels were measured and analyzed with t-test. The incidence of complications was followed up and analyzed with chi-square test or Fisher's exact test as appropriate. The risk factors for complications were analyzed using the logistic stepwise regression.

RESULTS

The blood glucose levels were higher in TIHA group than that in TIVA group at the time points of extubation, 1 and 2 h after the operation, 1 and 2 days after the operation, and were significantly higher at 1 day after the operation (10.4 ± 2.8 vs. 8.1 ± 2.1 mmol/L; P < 0.01). The postoperative insulin level was higher in TIVA group than that in TIHA group (8.9 ± 2.9 vs. 7.6 ± 2.4 IU/mL; P = 0.011). The postoperative cortisol level was higher in TIHA group than that in TIVA group (15.3 ± 4.8 vs. 12.2 ± 8.9 ug/dL ; P = 0.031). No significant difference regarding the incidence of complications between the two groups was found based on the current samples. Blood glucose level on postoperative day 1 was a risk factor for postoperative complications (OR: 1.779, 95%CI: 1.009 ~ 3.138).

CONCLUSIONS

TIVA has less impact on perioperative blood glucose level and a better inhibition of cortisol release in type 2 diabetic patients compared to TIHA. A future large trial may be conducted to find the difference of complications between the two groups.

TRIAL REGISTRATION

The protocol registered on the Chinese Clinical Trials Registry on 20/01/2020 (ChiCTR2000029247).

Effects of Total Intravenous Versus Inhalational Anesthesia on Bleeding During Endoscopic Ear Surgery: Preliminary Results From a Case-Control Study

OBJECTIVE

To assess the impact of the type of maintenance anesthesia on the bleeding conditions of the surgical field and hemodynamic parameters during endoscopic ear surgery (EES), comparing totally intravenous inhalational anesthesia (TIVA) with inhalational anesthesia (IA).

STUDY DESIGN

Retrospective case-control study.

SETTING

Tertiary referral center.

PATIENTS

Fifteen consecutive EES cases performed with TIVA between 2019 and 2020 at our Institution were matched to a control group of patients who underwent EES with IA in the same period. Patients with American Society of Anesthesiologists IV grade, acute otitis before surgery, congenital or acquired coagulopathies, use of anti-inflammatory drugs, or antiaggregant or anticoagulant therapy in the 5 days before the intervention were excluded.

INTERVENTIONS

Both primary and revision tympanoplasty and stapes surgery were considered.

MAIN OUTCOME MEASURES

Surgical videos were reviewed to quantify the entity of bleeding according to the Modena Bleeding Score. Hemodynamic parameters during surgery were retrospectively collected. A comparison between the two groups was performed.

RESULTS

No statistically significant differences between the two groups in terms of bleeding were found at any of time point evaluated. The tympanomeatal flap elevation resulted in the bloodiest step in both groups. Hemodynamic parameters were similar in both groups ( p > 0.05).

CONCLUSIONS

These preliminary data do not support a significant difference in bleeding conditions and hemodynamic parameters between EES patients receiving TIVA and those receiving IA. Further studies involving a higher number of patients will improve our understanding on how maintenance anesthesia with TIVA may be beneficial in terms of bleeding control as compared with IA for patients undergoing EES.

The effects of total intravenous and inhalation anesthesia maintenance on tissue oxygenation in coronary artery bypass graft surgery

OBJECTIVE

The aim of this study is to evaluate the effect of total intravenous anesthesia (TIVA) and inhalational anesthesia techniques on tissue oxygenation in cardiac surgery. We compared the effects of midazolam-based TIVA and sevoflurane-based (SEVO) inhalation anesthesia maintenance on intraoperative central and regional tissue oxygenation parameters.

PATIENTS AND METHODS

A total of 104 adult patients who were scheduled for elective isolated coronary bypass surgery were included in the study. All patients were divided into two groups: the TIVA group consisted of total intravenous anesthesia maintenance patients (n=52) and the SEVO group consisted of patients with inhalation anesthesia with sevoflurane maintenance (n=52). Tissue oxygenation values were observed with left-right cerebral and somatic left forearm Near-Infrared Spectroscopy (NIRS) sensors. The hemodynamic parameters, NIRS StO2, central (ScvO2) and peripheral venous oxygen saturations of the patients were recorded at six intraoperative time points.

RESULTS

The effects of midazolam-based TIVA and sevoflurane-based inhalation anesthesia maintenance on intraoperative central and peripheral tissue oxygenation parameters were compared and it was found that in the left forearm NIRS StO2 and ScvO2 values were higher in the SEVO group than the TIVA group. Although not significantly different, forearm regional venous oxygen saturation was also higher in the SEVO group.

CONCLUSIONS

The effects of anesthetic drugs on regional tissue oxygenation can become important in critical patients and challenging surgeries. Sevoflurane-based anesthesia provides better tissue oxygenation than TIVA in patients undergoing coronary bypass surgery.

Nitrous oxide improves cardiovascular, respiratory, and thermal stability during prolonged isoflurane anesthesia in juvenile guinea pigs

Anesthesia is frequently used to facilitate physiological monitoring during interventional animal studies. However, its use may induce cardiovascular (central and peripheral), respiratory, and thermoregulatory depression, confounding results in anesthetized animals. Despite the wide utility of guinea pigs as a translational platform, anesthetic protocols remain unstandardized for extended physiological studies in this species. Therefore, optimizing an anesthetic protocol that balances stable anesthesia with intact cardiorespiratory and metabolic function is crucial. To achieve this, 12 age and sex-matched juvenile Dunkin Hartley guinea pigs underwent extended anesthesia (≤150 min) with either (a) isoflurane (ISO: 1.5%), or (b) isoflurane + N2 O (ISO+ N2 O: 0.8% +70%), in this randomized cross-over designed study. Cardiovascular (HR, SBP, peripheral microvascular blood flow), respiratory (respiratory rate, SpO2 ), and thermal (Tre and Tsk ) measures were recorded continuously throughout anesthesia. Blood gas measures pre- and post- anesthesia were performed. Incorporation of 70% N2 O allowed for significant reductions in isoflurane (to 0.8%) while maintaining an effective anesthetic depth for prolonged noninvasive physiological examination in guinea pigs. ISO+N2 O maintained heart rate, peripheral blood flow, respiratory rate, and thermoregulatory function at levels closest to those of conscious animals, especially in females; however, it did not fully rescue anesthesia-induced hypotension. These results suggest that for studies requiring prolonged physiological examination (≤150 min) in guinea pigs, 0.8% isoflurane with a 70% N2 O adjuvant provides adequate anesthesia, while minimizing associated cardiorespiratory depression. The preservation of cardiorespiratory status is most marked throughout the first hour of anesthesia.

Anaesthesia and ICU sedation with sevoflurane do not reduce myocardial injury in patients undergoing cardiac surgery: A randomized prospective study

BACKGROUND

To evaluate the effect of anaesthesia and ICU sedation with sevoflurane to protect the myocardium against ischemia-reperfusion injury associated to cardiac surgery assessed by troponin release.

METHODS

We performed a prospective, open-label, randomized study in cardiac surgery with cardiopulmonary bypass. Patients were randomized to an algorithm-based intervention group and a control group. The main outcome was the perioperative kinetic of cardiac troponin I (cTnI). The secondary outcomes included composite endpoint, GDF-15 (macrophage inhibitory cytokine-1) value, arterial lactate levels, and the length of stay (LOS) in the ICU.

RESULTS

Of 82 included patients, 81 were analyzed on an intention-to-treat basis (intervention group: n = 42; control group: n = 39). On inclusion, the intervention and control groups did not differ significantly in terms of demographic and surgical data. The postoperative kinetics of cTnI did not differ significantly between groups: the mean difference was 0.44 ± 1.09 μg/ml, P = .69. Incidence of composite endpoint and GDF-15 values were higher in the sevoflurane group than in propofol group. The intervention and control groups did not differ significantly in terms of ICU stay and hospital stay.

CONCLUSION

The use of an anaesthesia and ICU sedation with sevoflurane was not associated with a lower incidence of myocardial injury assessed by cTnI. Sevoflurane administration was associated with higher prevalence of acute renal failure and higher GDF-15 values.

A Systematic Review and Meta-analysis of Clinical Trials of Neuraxial, Intravenous, and Inhalational Anesthesia for External Cephalic Version

BACKGROUND

External cephalic version (ECV) is a frequently performed obstetric procedure for fetal breech presentation to avoid cesarean delivery. Neuraxial, intravenous, and inhalational anesthetic techniques have been studied to reduce maternal discomfort caused by the forceful manipulation. This study compares the effects of these anesthetic techniques on ECV and incidence of cesarean delivery.

METHODS

We conducted a comprehensive literature search for published randomized controlled trials (RCTs) or well-conducted quasi-randomized trials of ECV performed either without anesthesia or under neuraxial, intravenous, or inhalational anesthesia. Pairwise random-effects meta-analyses and network meta-analyses were performed to compare and rank the perinatal outcomes of the 3 anesthetic interventions and no anesthesia control, including the rate of successful version, cesarean delivery, maternal hypotension, nonreassuring fetal response, and adequacy of maternal pain control/satisfaction.

RESULTS

Eighteen RCTs and 1 quasi-randomized trial involving a total of 2296 term parturients with a noncephalic presenting singleton fetus were included. ECV under neuraxial anesthesia had significantly higher odds of successful fetal version compared to control (odds ratio [OR] = 2.59; 95% confidence interval [CI], 1.88-3.57), compared to intravenous anesthesia (OR = 2.08; 95% CI, 1.36-3.16), and compared to inhalational anesthesia (OR = 2.30; 95% CI, 1.33-4.00). No association was found between anesthesia interventions and rate of cesarean delivery. Neuraxial anesthesia was associated with higher odds of maternal hypotension (OR = 9.33; 95% CI, 3.14-27.68). Intravenous anesthesia was associated with significantly lower odds of nonreassuring fetal response compared to control (OR = 0.36; 95% CI, 0.16-0.82). Patients received neuraxial anesthesia reported significantly lower visual analog scale (VAS) of procedure-related pain (standardized mean difference [SMD] = -1.61; 95% CI, -1.92 to -1.31). The VAS scores of pain were also significantly lower with intravenous (SMD = -1.61; 95% CI, -1.92 to -1.31) and inhalational (SMD = -1.19; 95% CI, -1.58 to -0.8) anesthesia. The VAS of patient satisfaction was significantly higher with intravenous anesthesia (SMD = 1.53; 95% CI, 0.64-2.43).

CONCLUSIONS

Compared to control, ECV with neuraxial anesthesia had a significantly higher successful rate; however, the odds of maternal hypotension increased significantly. All anesthesia interventions provided significant reduction of procedure-related pain. Intravenous anesthesia had significantly higher score in patient satisfaction and lower odds of nonreassuring fetal response. No evidence indicated that anesthesia interventions were associated with significant decrease in the incidence of cesarean delivery compared to control.

Inhaled anesthesia in neurosurgery: Still a role?

In patients undergoing craniotomy, general anesthesia should be addressed to warrant good hypnosis, immobility, and analgesia, to ensure systemic and cerebral physiological status and provide the best possible surgical field. Regarding craniotomies, it is unclear if there are substantial differences in providing general anesthesia using total intravenous anesthesia (TIVA) or balanced anesthesia (BA) accomplished using the third generation halogenates. New evidence highlighted that the last generation of halogenated agents has possible advantages compared with intravenous drugs: rapid induction, minimal absorption and metabolization, reproducible pharmacokinetic, faster recovery, cardioprotective effect, and opioid spare analgesia. This review aims to report evidence related to the use of the latest halogenated agents in patients undergoing craniotomy and to present available clinical evidence on their effects: cerebral and systemic hemodynamic, neurophysiological monitoring, and timing and quality of recovery after anesthesia.

Effects of sevoflurane inhalation anesthesia on IL-6, TNF-α and MMP-9 expression and hemodynamics in elderly patients undergoing lobectomy for lung cancer

Objective of current research was to investigate the effect of sevoflurane inhalation anesthesia on hemodynamics and inflammatory response in elderly patients with lung cancer lobectomy. Methods: A total of 168 patients with lung cancer who underwent lobectomy in our hospital from January 2019 to December 2019 were selected as the study subjects. The patients were divided into an observation group and control group according to the anesthesia program. In the control group, 1 mg/kg propofol intravenous pump induced anesthesia was maintained at 6mg/kg/h. In the observation group, 8% sevoflurane was used to induce anesthesia and 2% sevoflurane was used to maintain anesthesia. Mean artery pressure (MAP), heart rate (HR) and blood oxygen saturation (SpO2) were monitored at the beginning of single-lung ventilation (t1), when single-lung ventilation was changed to double-lung ventilation (t2), and at 30 minutes after double-lung ventilation (t3), respectively. Serum levels of interleukin-6 (IL-6), tumor necrosis factor (TNF-α), and matrix metalloproteinases (MMP-9) were measured using an enzyme-linked immunosorbent assay (ELISA) kit. Assess the patient's adverse reactions. Results: At time t1 and time t2, there was no significant difference in the three hemodynamic indicators between the two groups (P&gt;0.05). However, at t3, both MAP and HR in the observation group were significantly lower than those in the control group, while SpO2 was significantly higher than those in the control group (P&lt;0.05). At t1 and t2, there was no significant difference in IL-6 and TNF- levels between the two groups, but at t3, IL-6 and TNF-α levels in the observation group were significantly lower than those in the control group (P&lt;0.05). Compared with the control group, serum MMP-9 level was significantly decreased in the whole t1 to t3 stage (P&lt;0.05). The incidence of complications in the observation group was significantly higher than that in the control group. It was calculated that Sevoflurane can significantly improve hemodynamics and inflammatory response in elderly patients with lung cancer lobectomy, but the incidence of complications is high.

Arterial Oxygen Desaturation during only one of two Similar Thoracoscopic Procedures on the Same Patient

The present report describes two similar thoracoscopic procedures performed on the same 81-year-old male patient. Because acute hypoxia had developed during one-lung ventilation on the first occasion, serial blood gases were taken during the second. Also, whereas on the first occasion the non-ventilated lung had been left open to air when one-lung ventilation was initiated, on the second it was connected to an ambient pressure oxygen source with the object of theoretically enabling apnoeic oxygenation during lung collapse. It is argued that this fundamental difference in anaesthetic practice may have contributed to the improved oxygenation that was recorded during the second thoracoscopy.

The Relationship between Calculated Effect-site Sevoflurane Levels and Awakening from Anaesthesia

We have previously described a system that displays real-time estimates of effect-site sevoflurane concentrations. Estimates of effect-site levels should be similar to minimum alveolar concentration (MAC) values, which are determined after allowing time for equilibrium. This study aimed to determine estimated effect-site sevoflurane concentrations at awakening from routine anaesthesia and to compare this with published estimates of MAC-awake. If these values were similar, this would validate our approach to the calculation of effect-site concentration. Sixty-five patients undergoing a variety of surgical procedures were observed. Prior to disconnection from the breathing circuit, forward estimates of effect-site sevoflurane were recorded. Patients were observed in the postanaesthesiacare unit and the time at which they responded to comm and wasrecorded. Age-adjusted effect-site sevoflurane at the time of awakeningwas determined. Correlation with patient, surgical and anaestheticfactors includingage, gender, ASA status and intraoperative opioid usage were explored. Mean age-adjusted calculated effect-site concentration at awakening was 0.59 (SD 0.27) vol%. This value is within the range of values determined for MAC-awake of sevoflurane. There was no correlation with any of the demographic or anaesthetic factors, but patients undergoing major surgery woke at a significantly lower mean sevoflurane level. These results support the use of effect-site sevoflurane concentration to guide administration of anaesthesia.

The Single-connector Technique for Initial Placement of Double-lumen Tubes

Due to the presence of major lung or extra-pulmonary pathology, which may be unilateral or bilateral, the initial placement of a double-lumen tube is not always straightforward. Although fibreoptic bronchoscopy is often used to confirm “correct” placement, a “blind” technique is frequently used for the initial insertion. The currently widely taught blind technique involves tracheal cuff inflation and ventilation of both lungs as a first manoeuvre, with a subsequent assessment of single-lung ventilation by clamping off, in turn, the two limbs of the double-lumen tube double-connector. An alternative approach involves the bronchial cuff being inflated first, and then using a single-connector to transfer ventilation from one lung to the other. In this paper this technique is described and compared to the more traditional method. On a purely “number of steps” basis, the single-connector approach has several advantages. Furthermore, use of a technique that involves bronchial cuff inflation and single-lung ventilation as a first manoeuvre may reduce the risk of a temporarily malplaced double-lumen tube creating a potentially harmful ball-valve effect in a partially obstructed lobe or lung.

The Theoretical Basis for Using Apnoeic Oxygenation via the Non-ventilated Lung during One-lung Ventilation to Delay the Onset of Arterial Hypoxaemia

At the time one-lung ventilation is initiated, nitrogen from the atmosphere may enter the non-ventilated lung via a double-lumen tube connector that has been left open to air, even momentarily. Ongoing oxygen uptake from the non-ventilated lung raises the partial pressure of nitrogen. This should lead to activation of hypoxic pulmonary vasoconstriction and a reduction in intra-pulmonary shunting. However, in spite of this, some patients still become hypoxaemic. In such cases, it may be advantageous to have excluded nitrogen from the non-ventilated lung by connecting it to an oxygen source at ambient pressure. Ongoing apnoeic oxygenation, while the airways are patent, and as the lung collapses, should delay the onset of arterial desaturation. In this paper we review the theoretical basis for apnoeic oxygenation during one-lung ventilation, and in particular on oxygen uptake by the non-ventilated lung prior to and during its subsequent collapse.

An Audit of the Single Use Portex Laryngeal Mask

We performed an audit of the insertion of the Single Use Portex Laryngeal Mask in 400 patients. Insertion was successful at first attempt in 335 out of 400 patients (83.8%). However in 15 patients (3.8%), the Portex laryngeal mask could not be placed despite repeated attempts. In 12 of these 15 patients (80%), a standard Laryngeal Mask Airway (LMA) was successfully placed. After the completion of the audit, 22 out of 29 anaesthetists (75.9%), who had inserted 5 Portex laryngeal masks, considered it inferior to the standard LMA. It would appear to us that the Portex laryngeal mask might need some design modifications to be a real alternative to the standard LMA.

From Dental to Mental Institutions: Elmer McKesson's Secondary Saturation with Nitrous Oxide

As popularized by Elmer McKesson, MD, "secondary saturation" with nitrous oxide could expose patients to a second burst of 100% laughing gas to relax their muscles to assist surgeons. On rare occasions, this technique could provide a second opportunity for hypoxic brain damage and possible admission postoperatively to insane asylums.

Cardiovascular and respiratory effects of two doses of fentanyl in the presence or absence of bradycardia in isoflurane-anesthetized dogs

OBJECTIVE

To compare the cardiopulmonary effects of low and high doses of fentanyl before and after the correction of bradycardia in isoflurane-anesthetized dogs.

STUDY DESIGN

Prospective, randomized crossover trial.

ANIMALS

Eight healthy male Beagle dogs weighing 11.1 ± 1.3 kg [mean ± standard deviation (SD)] and aged approximately 1 year.

METHODS

The dogs were anesthetized with isoflurane [1.3 × minimum alveolar concentration (MAC)] on two occasions and fentanyl was administered intravenously; either low-dose fentanyl, loading dose (33 μg kg-1) and infusion (0.2 μg kg-1 minute-1) or a high-dose, loading dose (102 μg kg-1) and infusion (0.8 μg kg-1 minute-1). Cardiopulmonary variables were measured at three time points in equipotent isoflurane concentrations (1.3 MAC): before fentanyl administration (ISO), during fentanyl-induced bradycardia (ISO-F) and after administration of glycopyrrolate normalized heart rate (ISO-FNHR). Data are mean ± SD.

RESULTS

Heart rate and cardiac index (CI) decreased and systemic vascular resistance index (SVRI) increased at ISO-F in both treatments. Bradycardia and vasoconstriction at ISO-F were greater in high than in low-dose fentanyl (42 ± 7 versus 57 ± 15 beats minute-1 and 3457 ± 1108 versus 2528 ± 968 dyne second cm-5 m-2), respectively. Oxygen delivery index (DO2I) decreased only during high-dose fentanyl. CI and DO2I were higher in both treatments at ISO-FNHR than at ISO-F; however, they were higher only during the high-dose fentanyl than at ISO. SVRI was higher at ISO-F than at ISO and ISO-FNHR in both treatments, and was higher at ISO-F in the high than in the low-dose treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

An overall improvement in cardiovascular function of dogs anesthetized with equipotent isoflurane doses (1.3 MAC) was observed after the treatment of bradycardia only with the high-dose fentanyl.

The Perfect and Famous Anesthetic Known as Methyl in Boston in 1895

Extravagant claims were made for proprietary dental anesthetics in Boston, MA, in the late 1800s. For instance, in 1883, Urial K. Mayo introduced an inhaled Vegetable Anaesthetic comprised of nitrous oxide that had been uselessly pretreated with botanical material. This misguided concept may have been inspired by homeopathy, but it was also in line with the earlier false belief of Elton R. Smilie, Charles T. Jackson, and William T.G. Morton that sulfuric ether could volatilize opium at room temperature. In 1895, the Dental Methyl Company advertised an agent they called Methyl, a supposedly perfect topical anesthetic for painless dental extraction. The active ingredient was probably chloroform. Anesthetic humbug did not cease in Boston on Ether Day of October 16, 1846.

Desflurane versus sevoflurane in pediatric anesthesia with a laryngeal mask airway: A randomized controlled trial

BACKGROUND

Desflurane with a laryngeal mask airway may have advantages during ambulatory anesthesia. However, desflurane-induced airway irritability makes the use of desflurane challenging, especially in children. This study compared desflurane with sevoflurane maintenance anesthesia in terms of respiratory events and the emergence characteristics in children with a laryngeal mask airway.

METHODS

This randomized controlled trial evaluated 200 children undergoing strabismus surgery allocated to desflurane or sevoflurane groups. After inducing anesthesia with sevoflurane and thiopental sodium 5 mg kg, the anesthetic agent was changed to desflurane in the desflurane group, whereas sevoflurane was continued in the sevoflurane group. Respiratory events, emergence time, recovery time, and emergence agitation were compared between the groups.

RESULTS

The overall respiratory events did not differ between the groups. However, the incidence of mild desaturation (90% ≤ SpO2 < 97%) was significantly higher in the desflurane group (7%) than in the sevoflurane group (0%) (P = .007). Emergence was significantly faster in the desflurane group (6.6 ± 3.9 vs 8.0 ± 2.2 min, P = .003). The recovery time and emergence agitation in the postanesthesia care unit were comparable between groups. Laryngospasm developed in 5 children (1 in the sevoflurane group and 4 in the desflurane group, P = .365); of these, 4 patients were younger than 3 years.

CONCLUSION

Desflurane maintenance anesthesia in children with a laryngeal mask airway shows a similar rate of overall respiratory events compared with sevoflurane anesthesia. However, anesthesiologists should be cautious of using desflurane in younger children concerning desaturation events during emergence.

Efficacy of continuous positive airway pressure and incentive spirometry on respiratory functions during the postoperative period following supratentorial craniotomy: A prospective randomized controlled study

STUDY OBJECTIVE

Volume controlled ventilation with low PEEP is used in neuro-anesthesia to provide constant PaCO₂ levels and prevent raised intracranial pressure. Therefore, neurosurgery patients prone to atelectasis formation, however, we could not find any study that evaluates prevention of postoperative pulmonary complications in neurosurgery.

DESIGN

A prospective, randomized controlled study.

SETTING

Intensive care unit in a university hospital in Istanbul.

PATIENTS

Seventy-nine ASAI-II patients aged between 18 and 70years scheduled for elective supratentorial craniotomy were included in the study.

INTERVENTIONS

Patients randomized into 3 groups after surgery. The Group IS (n=20) was treated with incentive spirometry 5 times in 1min and 5min per hour, the Group CPAP (n=20) with continuous positive airway pressure 10 cmH₂O pressure and 0.4 F_iO₂ via an oronasal mask 5min per hour, and the Group Control (n=20) 4L·min^-1O₂ via mask; all during the first 6h postoperatively. Respiratory functions tests and arterial blood gases analysis were performed before the induction of anesthesia (Baseline), 30min, 6h, 24h postoperatively.

MAIN RESULTS

The IS and CPAP applications have similar effects with respect to FVC values. The postoperative 30min FEV₁ values were statistically significantly reduced compared to the Baseline in all groups (p<0.0001). FEV₁ values were statistically significantly increased at the postoperative 24h compared to the postoperative 30min in the Groups IS and CPAP (p<0.0001). This increase, however, was not observed in the Group Control, and the postoperative 24h FEV₁ values were statistically significantly lower in the Group Control compared to the Group IS (p=0.015).

CONCLUSION

Although this study is underpowered to detect differences in FEV₁ values, the postoperative 24h FEV₁ values were significantly higher in the IS group than the Control group and this difference was not observed between the CPAP and Control groups. It might be evaluate a favorable effect of IS in neurosurgery patients. But larger studies are needed to make a certain conclusion.

Isoflurane minimum alveolar concentration sparing effects of fentanyl in the dog

OBJECTIVE

To characterize the isoflurane-sparing effects of a high and a low dose of fentanyl in dogs, and its effects on mean arterial pressure (MAP) and heart rate (HR).

STUDY DESIGN

Prospective, randomized crossover trial.

ANIMALS

Eight healthy male Beagle dogs weighing 12.1 ± 1.6 kg [mean ± standard deviation (SD)] and approximate age 1 year.

METHODS

Dogs were anesthetized using isoflurane and minimum alveolar concentration (MAC) was determined in duplicate by the bracketing method using an electrical stimulus on the tarsus. Animals were administered fentanyl: low dose (33 μg kg-1 loading dose, 0.2 μg kg-1 minute-1) or high dose (102 μg kg-1 loading dose, 0.8 μg kg-1 minute-1) and MAC was re-determined (MACISO-F). Blood was collected for analysis of plasma fentanyl concentrations before administration and after MACISO-F determination. All values are presented as mean ± SD.

RESULTS

Isoflurane MAC (MACISO) was 1.30 ± 0.23% in the low dose treatment, which significantly decreased to 0.75 ± 0.22% (average MAC reduction 42.3 ± 9.4%). MACISO was 1.30 ± 0.18% in the high dose treatment, which significantly decreased to 0.30 ± 0.11% (average MAC reduction 76.9 ± 7.4%). Mean fentanyl plasma concentrations were 6.2 and 29.5 ng mL-1 for low and high dose treatments, respectively. MAP increased significantly only in the high dose treatment (from 81 ± 8 to 92 ± 9 mmHg). HR decreased significantly in both treatments from 108 ± 25 to 61 ± 14 beats minute-1 with the low dose and from 95 ± 14 to 42 ± 4 beats minute-1 with the high dose.

CONCLUSIONS AND CLINICAL RELEVANCE

Fentanyl administration resulted in a dose-dependent isoflurane MAC-sparing effect with bradycardia at both doses and an increase in MAP only at high dose. Further evaluation is needed to determine the effects of fentanyl on the overall cardiovascular function.

Relationship between anesthesia and postoperative endophthalmitis: A retrospective study

Previous study showed that patients under general anesthesia (GA) had nasopharyngeal secretions on the face at the end of ocular surgery, especially in propofol-based total intravenous anesthesia (TIVA), it might induce postoperative endophthalmitis. Therefore, we conducted a retrospective study to compare the incidence of endophthalmitis after ocular surgery under topical, inhalation anesthesia, and propofol-based TIVA in our medical center from 2011 to 2015.A total of 21,032 patients were included, and we evaluated epidemiologic factors, systemic diseases, other ocular pathologic characteristics, complications during the surgery, technique of ocular surgery, method of antibiotic prophylaxis, vitreous culture, and vision outcome in these patients.Fifteen endophthalmitis cases among 21,032 operations reported, equaling an incidence of 0.071%. The incidence rates under topical, inhalation anesthesia, and propofol-based TIVA were 0.083%, 0.039%, and 0%, respectively (P = 0.39). Moreover, the risk of endophthalmitis under GA (0.024%) was significantly lower than topical anesthesia (0.083%) (P < 0.001). We also found that elder was the risk factor for endophthalmitis following ocular surgery.In conclusion, propofol-based TIVA or inhalation anesthesia did not increase the risk of endophthalmitis after ocular surgery. Thus, GA was not a risk factor for postoperative endophthalmitis. By contrast, elder was the risk factor for postoperative endophthalmitis.

COMPARISON OF EMERGENCE AND RECOVERY CHARACTERISTICS OF SEVOFLURANE AND DESFLURANE IN PEDIATRIC AMBULATORY SURGERY

BACKGROUND

A big number ofshort-time surgery performed in one-day pediatric department requires the permanent search of an ideal anesthetic for the maximum quickly children ' take home with the minimum ofpostoperation complications.

THE AIM

to compare the emergence and recovery characteristics ofsevoflurane and desflurane maintenance ofanesthe- sia in children undergoing ambulatory surgery.

RESULTS AND CONCLUSION

There were no significant differences among the two groups in hemodynamic parameters, the incidence of postoperative vomiting and cough. But desflurane maintenance of anesthesia resulted in the fastest early emergence from anesthesia, the lack of incidence ofpostoperative agitation compared with sevoflurane.

[Selection of inhalation anaesthetic when low-flow anaesthesia with automated control]

Selection of inhalation anaesthetic when low-flow anaesthesia with automated control. A comparative evaluation of low-flow (0,5 l/min) and inhalation anaesthesia with sevoflurane and desfluranom with automated control of the concentration of inhaled anaesthetic on the exhale (Et-control), with the use of advanced monitoring in 76 patients operated on for the pathology of the spine and spinal cord is given. It was found that when using continuous measuring the achievement of the target concentration of the anaesthetic sevoflurane is faster in the group. Total consumption of desflurane was two times higher. Hemodynamic, SPI index were stable at all stages of the operation in both groups.

ANESTHETIC MANAGEMENT AND INTENSIVE CARE DURING PERIOPERATIVE PERIOD OF ABDOMINAL DELIVERY IN PREGNANT WOMEN WITH PULMONARY ARTERIAL HYPERTENSION

Background The presence ofpulmonary arterial hypertension (PAH) in pregnant women increases mortality up to 12- 30% and up to 50% when PAH is associated with Eisenmenger syndrome. Due to low prevalence of PAH in pregnancy many aspects ofperioperative management are still unclear.

THE AIM

To summarize our approaches to the anesthesia and intensive care in pregnant women with PAH.

MATERIALS AND METHODS

21 pregnant women with PAH (systolic pulmonary artery pressure (SPAP) higher than 60 mm Hg)-who underwent delivery by Caesarean section in 2010 - 2015 were included in the one-centre retrospective study. Data are presented as median (25th, 75th percentile).

RESULTS

The median age was 27 (23; 29) years. Among the patients, there were 4 (19%) cases of idiopathic PAH and in 17 (81%) women PAH was associated with congenital heart disease (CHD); 12 (57%) patients'demonstrated Eisenmenger syndrome. Baseline SPAP was 90 (82; 103) mm Hg. SpO2 90 (85,95)%. All women taken PAH-specific therapy (sildenafil) before delivery. Caesarean section (CS) were performed at 32 (28; 34) weeks. In 20 cases CS was perfofined under epidural anesthesia and in one case under general anesthesia due thrombocytopenia. Inhaled nitric oxide (NO) was administered intraoperative to all women in a dose of 40-60 ppm. Postoperative period was uncomplicated in five women (23?8%). Decompensation with PAP rise, acute right ventricular failure and hypoxemia developed in 16 (76,2%) cases 30 (24, 40) h after abdominal delivery. These patients required combined PAH-specific therapy (NO, sldenafil, iloprost) and inotropic agents, additionallyrespiratory support was used in four patients. The median ICU stay was 13 (9; 22) days. 3 patients died (14?2%); mortality in Eisenmenger syndrome cases was 25% (3/12). 18 healthy babies.

EVALUATION OF EFFICACY AND SAFETY POSTOPERATIVE PAIN MANAGEMENT BY INTRAMUSCULAR ANALGESIA AFTER DIFFERENT TYPES OF ANAESTHESIA: PILOT CLINICAL PROSPECTIVE STUDY

MATERIAL AND METHODS

Efficacy Safety Score (ESS) with "call-out algorithm" developed in Kongsberg hospital, Norway was used for the validation. ESS consists of the mathematical sum ofscorefrom: 2 subjective (Visual Analog Scale: VAS at rest and during mobilization) and 4 vital (conscious levels, PONV circulation and respiration status) parameters and ESS > 10 is a "call-out alarm "for visit ofpatient by anaesthesiologist. Hourly registration of ESS, mobility degree and amounts of analgetics during the first 8 hours after surgery was recorded in the specially designed IPad program. According to the type ofanaesthesia all patients were allocated in 4 groups: I spinal anaesthesia (SA), II general anesthesia (GA), III peripheral blockade (PB) and IV Total intravenous anaesthesia (TIVA).

RESULTS AND DISCUSSION

A total of 223 patients were included in the study. Statistically low levels of both VAS and ESS in the first 2-4 postoperative hours were found in SA and PB groups compared to GA and TIVA groups. During 8 post-operative hours, VAS> 3 was recorded in 10.5% of SA, 13.9% in GA, 12.8% in PG and 23.5% in TIVA patients.

CONCLUSIONS

Intramuscular postoperative analgesia was effective in SA, GA and PG groups. More attention of anaesthesiologist must be paid to patients ofter TIVA.

Selective lung intubation during paediatric thoracic surgeries

Selective lung intubation is a necessary prerequisite for the completion of most interventions comprising thoracotomy and thoracoscopy. In paediatric care, our site uses Univent tubes for children up to the age of three years and double-lumen tubes (DLT) for children from 6-8 years of age. In younger children, we usually use regular endotracheal intubation, with the lung being held in the hemithorax position being operated on using a surgical retractor. The article presents the analysis of 860 thoracic surgeries, of which 491 comprised selective intubation (Univent 57 cases, DLT 434 cases). The use of the aforementioned devices is connected with certain complications. Univent tube can be connected with intraoperative dislocation of the obturating balloon (29.8%) and balloon perforation (5.2%). DLT insertion may be connected with failure of tube fitting. In 84 cases we had to repeat DLT insertion (20.6%). In 8 cases we were not able to insert DLT at all (1.8%). Standard use of selective intubation methods in paediatric patients from two years of age improved the conditions for surgical interventions (Tab. 2, Fig. 2, Ref. 19).

One-Lung Anesthesia Update

One-lung ventilation is used during a variety of cardiac, thoracic, and major vascular procedures. Endobronchial tubes, bronchial blockers, and occasionally, single-lumen tubes are used to isolate the lungs. Patients with difficult airways and pediatric patients provide special challenges for lung isolation. Finally, intraoperative hypoxia and hypercarbia in patients with intrinsic lung disease frequently complicate one-lung anesthesia. The concepts and controversies in lung isolation techniques are discussed.

Evaluation of CO2 anaesthesia applied by a commercial device for the castration of male suckling piglets under field conditions

The aim of this study was to describe clinical and behavioural parameters of piglets castrated with the use of CO2 anaesthesia by using the commercial available device MS Pigsleeper. 80 male piglets with three to six days of age were allocated to four groups, and were castrated or left uncastrated either after receiving 70% CO2/30% O02, or without anaesthesia. Defensive movements and heart rates were measured during induction and castration phase. At castration phase the dewclaw reflex was tested and piglets were monitored for vocalisation. During recovery and the subsequent five minutes conspicuous behaviours were recorded. Intensity of defensive movements was significantly higher in groups with CO2 anaesthesia during induction phase. Defensive movements were significantly lower in groups with CO2, but also not fully absent, during castration phase. Surgical tolerance was only reached by 20% (4/20) of piglets castrated under anaesthesia. Heart rates were above physiological levels at the beginning of induction phase and dropped significantly thereafter. Dropping of heart rates was more pronounced in anaesthetised groups leading to significant differences compared to non-anaesthetised groups. A minimum heart rate of 20 beats per minute was measured. Conspicuous behaviours as spasms, gasping and licking were described for pigs after CO2 anaesthesia. Measured parameters implicated stress and discomfort during induction and recovery phase and severe cardiovascular depression during CO2 anaesthesia. Surgical tolerance was reached by only a small proportion of anaesthetised piglets. Therefore, welfare aspects were not met using CO2 anaesthesia for piglet castration in general and especially by applying the gas anaesthesia with the commercial device MS Pigsleeper.

High initial concentration versus low initial concentration sevoflurane for inhalational induction of anaesthesia

BACKGROUND

Sevoflurane induction for general anaesthesia has been reported to be safe, reliable and well accepted by patients. Sevoflurane induction uses either low or high initial concentrations. The low initial concentration technique involves initially administering a low concentration of sevoflurane and gradually increasing the concentration of the dose until the patient is anaesthetized. The high initial concentration technique involves administering high concentrations from the beginning, then continuing with those high doses until the patient is anaesthetized. This review was originally published in 2013 and has been updated in 2016.

OBJECTIVES

We aimed to compare induction times and complication rates between high and low initial concentration sevoflurane anaesthetic induction techniques in adults and children who received inhalational induction for general anaesthesia. We defined 'high' as greater than or equal to and 'low' as less than a 4% initial concentration.

SEARCH METHODS

For the updated review, we searched the following databases: Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 2), MEDLINE (1950 to February 2016), EMBASE (1980 to February 2016), Latin American Caribbean Health Sciences Literature (LILACS) (1982 to February 2016) and the Institute for Scientific Information (ISI) Web of Science (1946 to February 2016). We also searched the reference lists of relevant articles and conference proceedings and contacted the authors of included trials. The original search was run in September 2011.

SELECTION CRITERIA

We sought all published and unpublished, randomized controlled trials comparing high versus low initial sevoflurane concentration inhalational induction. Our primary outcomes included two measures of anaesthesia (time to loss of the eyelash reflex (LOER) and time until a weighted object held in the patient's hand was dropped), time to successful insertion of a laryngeal mask airway (LMA) and time to endotracheal intubation. Other outcomes were complications of the technique.

DATA COLLECTION AND ANALYSIS

We used standardized methods for conducting a systematic review as described in the Cochrane Handbook for Systematic Reviews of Interventions. Two review authors independently extracted details of trial methods and outcome data from reports of all trials considered eligible for inclusion. We conducted all analyses on an intention-to-treat basis, when possible. We estimated overall treatment effects by using a fixed-effect model when we found no substantial heterogeneity, whereas we applied the random-effects model in the presence of considerable heterogeneity.

MAIN RESULTS

We reran the searches and included one new study (100 participants) in this updated review. In total, we included 11 studies with 829 participants, although most analyses were based on data from fewer participants and evidence of low quality. We noted substantial heterogeneity in the included trials. Thus, our results should be read with caution. It was not possible to combine trials for the primary outcome (LOER), but individual trials reported faster induction times (typically 24 to 82 seconds faster, 41 seconds (31.37 to 50.62)) with high initial concentration sevoflurane (six studies, 443 participants, low-quality evidence). Apnoea appeared to be more common in the high initial concentration sevoflurane group (risk ratio (RR) 3.14, 95% confidence interval (CI) 1.72 to 5.7, two studies, 160 participants, low-quality evidence). We found no evidence of differences between the two groups in the incidence of cough (odds ratio (OR) 1.23, 95% CI 0.53 to 2.81, eight studies, 589 participants, low-quality evidence), laryngospasm (OR 1.59, 95% CI 0.16 to 15.9, seven studies, 588 participants, low-quality evidence), breath holding (OR 1.16, 95% CI 0.47 to 2.83, five studies, 389 participants, low-quality evidence), patient movement (RR 1.14, 95% CI 0.69 to 1.89, five studies, 445 participants, low-quality evidence) or bradycardia (OR 0.8, 95% CI 0.22 to 2.88, three studies, 199 participants, low-quality evidence), and the overall incidence of complications was low.

AUTHORS' CONCLUSIONS

A high initial concentration sevoflurane technique probably offers more rapid induction of anaesthesia and a similar rate of complications, except for apnoea, which may be more common with a high initial concentration. However, this conclusion is not definitive because the included studies provided evidence of low quality.

Blood sampling from the cranial vena cava in the Norway rat (Rattus norvegicus)

This paper describes blood sampling from the cranial vena cava (CVC) in the Norway rat. In order to limit stress, the blood sampling should be done under short-term inhalation anaesthesia, for example, an oxygen/isoflurane mixture. The injection site is just cranial to the first rib, 0.3–0.8 cm lateral to the manubrium when the animal is in dorsal recumbency. The needle, attached to a syringe, is inserted at 30° in the direction of the opposite femoral head. After penetration of the skin, negative pressure is developed in the syringe and the insertion of the needle is continued for another 0.2–1 cm in the given direction until blood begins to flow. The amount of blood sampled ranges from 0.8 to 2.5 mL depending on the body weight of the patient. A trial on 50 rats aged 5–24 months included 25 rats sampled once, eight rats sampled twice with an interval of seven days, 11 rats sampled twice with an interval of three weeks and four rats sampled four times with intervals of four weeks – a total of 87 blood samplings. The serious complications quoted in association with blood sampling from the CVC in other experimental animals (vascular lacerations, heart puncture, serious haemorrhage, tracheal and throat trauma) were not observed in our study. There were only four blood samplings (4.5%) with mild haemorrhage from the injection site, due to erroneous sampling from the jugular vein.

[ENTROPY MONITORING DURING LOW-FLOW INHALATION ANESTHESIA--A TRIBUTE TO FASHION OR NECESSITY?]

OBJECTIVE

To compare anesthesia quality and sevoflurane consumption during standard and extended intraoperative monitoring.

MATERIALS AND METHODS

74 patients were included in prospective randomized study. Patients had spinal pathology of varying severity, extension and localization. A comparative evaluation of standard and extended (with entropy) monitoring was performed during low-flow inhalation anesthesia with the automated control of the anesthetic concentration and exhaled oxygen fraction (Et-control).

RESULTS

Monitoring depth of anesthesia based on entropy enables more accurate dosing of inhaled anesthetics.

CONCLUSIONS

The study revealed that the use of entropy monitoring in high-risk surgery alleviates providing the controlled anesthesia with the optimal inhalation anesthetic concentration and minimal hemodynamic reactions of the patient.

The effects of anesthetic agents on pupillary function during general anesthesia using the automated infrared quantitative pupillometer

Pupil reactivity can be used to evaluate central nervous system function and can be measured using a quantitative pupillometer. However, whether anesthetic agents affect the accuracy of the technique remains unclear. We examined the effects of anesthetic agents on pupillary reactivity. Thirty-five patients scheduled for breast or thyroid surgery were enrolled in the study. Patients were divided into four groups based on the technique used to maintain anesthesia: a sevoflurane-remifentanil (SEV/REM) group, a sevoflurane (SEV) group, a desflurane-remifentanil (DES/REM) group, and a propofol-remifentanil (PRO/REM) group. We measured maximum resting pupil size (MAX), reduction pupil size ratio (%CH), latency duration (LAT) and neurological pupil index (NPi). A marked reduction in MAX and %CH compared with baseline was observed in all groups, but LAT was unchanged during surgery. NPi reduced within the first hour of surgery in the SEV/REM, SEV, and DES/REM groups, but was not significantly different in the PRO/REM group. Compared with the PRO/REM group, mean %CH and NPi in patients anesthetized with SEV/REM, SEV or DES/REM were markedly lower at 1 h after surgery had commenced. There was no correlation between NPi and bispectral index. Fentanyl given alone decreased pupil size and %CH in light reflex, but did not change the NPi. NPi was decreased by inhalational anesthesia not but intravenous anesthesia. The difference in pupil reactivity between inhalational anesthetic and propofol may indicate differences in the alteration of midbrain reflexs in patients under inhalational or intravenous anesthesia.

Could "safe practice" be compromising safe practice? Should anesthetists have to deflate the cuff of the endotracheal tube before extubation?

Deflation of the cuff of the endotracheal tube (ETT) before tracheal extubation is considered mandatory and safe practice. However, there are potential shortcomings associated with this practice (e.g., aspiration around the uncuffed ETT, loss of positive airway pressure, difficulty in generating an effective cough at the time of extubation). By contrast, keeping the cuff inflated during extubation will minimize the risk of tracheal aspiration around the ETT, and it will reliably allow maintenance of positive airway pressure until extubation, effective lung recruitment before extubation, and generation of an effective cough during extubation. All of these factors might reduce the overall risk of immediate postextubation and postoperative respiratory and pulmonary complications. Mandatory monitoring of cuff pressure ensures a remaining rather small, highly compressible cuff volume around the ETT which is unlikely to carry per se the risk of producing laryngeal trauma. In my view, as the overall advantages of not deflating the cuff before extubation outweigh the disadvantages, anesthetists should not have to deflate the cuff of the ETT before extubation. Ultimately, only a randomized controlled trial will be able to assess the effect of such practice on patient outcome.

Management of Anesthesia in a Child with a Large Neck Rhabdoid Tumor

OBJECTIVE

The aim of this paper was to report the management of anesthesia of a child with a large neck rhabdoid tumor.

CLINICAL PRESENTATION AND INTERVENTION

A 9-month- old female patient underwent urgent neck tumor excision due to intratumoral bleeding from a large tumor that compressed and dislocated the trachea; therefore, intubation was expected to be difficult. Sevoflurane inhalation induction was utilized to maintain spontaneous respiration. Oral laryngoscopy revealed Cormack-Lehane grade 3 laryngeal view. The trachea was intubated using a reinforced tube on the third attempt. Fiberoptic bronchoscope-assisted intubation was planned as an alternative in case of conventional intubation failure. Anticipation of massive blood loss necessitated central venous catheterization.

CONCLUSION

Establishing a safe airway, intubation during spontaneous breathing and invasive hemodynamic monitoring are crucial factors in the anesthetic management of pediatric patients with a large neck tumor.

Two different techniques of facial mask induction of anesthesia in children provide identical intubation conditions despite different anesthetic depth

BACKGROUND

Sevoflurane induction in chil- dren is performed using different techniques. Constricted, centered, and symmetrical pupils (CCSP) are classically the endpoint to be achieved before laryngoscopy is performed.

OBJECTIVES

We investigated whether two different inhalation induction techniques with the same clinical end- point provided similar intubating conditions and comparable depth of anesthesia as assessed by the Bispectral Index (BIS).

METHODS

Following IRB approval, and informed parental consent, 20 children were recruited. They were sched- uled for general anesthesia with tracheal intubation, and randomly assigned to Group 1, where the practitioner used 6% inspired sevoflurane in 50% 0₂/N₂0, and no manually assisted ventilation, or Group 2, where inspired sevoflurane was 8% in 50% 0₂/N₂0, and ventilation was manually supported upon loss of consciousness. BIS values were blinded. Laryngoscopy was performed after CCSP. Intubation conditions scoring was based on jaw relaxation (mobile = 1, partially mobile = 2, fixed = 3), position of vocal cords (open = 1, half-closed = 2, closed = 3), and cough (no cough = 1, 1 or 2 coughing efforts = 2, persistent coughing = 3). A total score > 3 corresponded to non-optimal conditions.

RESULTS

Upon CCSP, BIS values were significantly lower in Group 1 [mean (SD) : 30 (8) - 48 (18), p <0.001], despite significantly higher end-tidal sevoflurane concentration in Group 2 [mean (SD) : 5.0 (0.7) - 6.2 (0.5) ; p <0.001]. Time to CCSP was slightly shorter in Group 2. Intubation conditions were always optimal except for one patient of Group 1.

DISCUSSION

Both induction techniques achieve good intubating conditions. Possible explanations for the between-group BIS difference include variable appreciation of the CCSP endpoint, different induction lengths or sevoflurane equilibration times, or sevoflurane-induced increase in electroencephalogram power. A better indicator of the best time to intubate is needed to avoid too deep anesthesia in children.

Potent Inhalational Anesthetics for Dentistry

Nitrous oxide and the volatile inhalational anesthetics have defined anxiety and pain control in both dentistry and medicine for over a century. From curious experimentation to spectacular public demonstrations, the initial work of 2 dentists, Horace Wells and William T. G. Morton, persists to this day in modern surgery and anesthesia. This article reviews the history, similarities, differences, and clinical applications of the most popular inhalational agents used in contemporary dental surgical settings.

[Management of difficult airway with inhalation induction in a patient with Lennox-Gastaut syndrome and neck injury]

Lennox-Gastaut syndrome is a childhood epileptic encephalopathy, and is characterized by frequent and difficult to treat seizures associated with mental retardation. The case is presented of a 21 year-old male with Lennox-Gastaut syndrome, with bilateral cervical facet joint dislocation fracture at C6-C7 and spinal canal compression as a result of a fall during a seizure. In this case the management of the difficult airway expected in an awake and uncooperative patient, with cervical spinal cord injury is described. An airway management strategy was proposed, that allowed a rapid and safe airway control with the best possible tolerance and maintaining the neck immobilised, so as not to increase neurological injury. Within this strategy, plan A was defined as inhalation induction with sevoflurane to maintain spontaneous breathing and tracheal intubation with Airtraq®. We believe that the Airtraq® video laryngoscope with inhalational induction with sevoflurane is a valid and effective alternative in the management of expected difficult airway.

Sevoflurane Output in the Isoflurane/Halothane Diamedica Draw-over Vaporiser

INTRODUCTION

Draw-over anaesthesia remains an attractive option for conduct of anaesthesia in austere conditions. The Diamedica Draw-over Vaporiser (DDV) is a modern draw-over vaporiser and has separate models for isoflurane/halothane and sevoflurane.

MATERIALS AND METHODS

A laboratory study was done to measure sevoflurane output in an isoflurane/ halothane DDV. We did 3 series of experiments with the isoflurane/halothane DDV. We measured anaesthetic agent output in both push-over and draw-over setups, and at minute ventilation of 6 L/min and 3 L/min. Series 1 experiment was done with isoflurane in the DDV at ambient temperature of 20°C. Series 2 experiment was done with sevoflurane in the DDV at ambient temperature of 20°C. Series 3 experiment was done with sevoflurane in the DDV and with the DDV placed in a water bath of 40°C.

RESULTS

The sevoflurane output was found to be two-thirds of the isoflurane/ halothane DDV dial setting at ambient temperature of 20°C. With the DDV in a 40°C water bath, the sevoflurane output was found to be about the isoflurane/ halothane DDV dial settings.

CONCLUSION

In our experiment, we show that it is possible to use sevoflurane in an isoflurane/halothane DDV.

[THE EXPERIENCE OF ANAESTHESIA MANAGEMENT FOR SENSING OF NASOLACRIMAL DUCT IN CHILDREN]

Despite low invasiveness, lacrimal passages, intubation in children requires general anaesthesia to prevent traumatic and neurological complications. General anaesthesia with sevoflurane is optimal for technical simplicity, safety and controllability. Methods of face mask inhalation anesthesia with halothan and sevoflurane were compared in 996 patients. The authors have developed their own standart of performing the face mask inhalation anesthesia with sevoflurane in children during lacrimal passages intubation. This allowed to minimize the number of intra- and postoperative complications in children, to reduce period of postanesthetic observation, to advance the peroral compensation of fluid deficit.