Preventing Prolonged Times to Awakening While Mitigating the Risk of Patient Awareness: Gas Man Computer Simulations of Sevoflurane Consumption From Brief, High Fresh Gas Flow Before the End of Surgery

Prolonged times to tracheal extubation are associated with adverse patient and economic outcomes. We simulated awakening patients from sevoflurane after long-duration surgery at 2% end-tidal concentration, 1.0 minimum alveolar concentration (MAC) in a 40-year-old. Our end-of-surgery target was 0.5 MAC, the Michigan Awareness Control Study's threshold for intraoperative alerts. Consider an anesthetist who uses a 1 liter/minute gas flow until surgery ends. During surgical closure, the inspired sevoflurane concentration is reduced from 2.05% to 0.62% (i.e., MAC-awake). The estimated time to reach 0.5 MAC is 28 minutes. From a previous study, 28 minutes exceeded ≥95% of surgical closure times for all 244 distinct surgical procedures (N=23,343 cases). Alternatively, the anesthetist uses 8 liters/minute gas flow with the vaporizer at MAC-awake for 1.8 minutes, which reduces the end-tidal concentration to 0.5 MAC. The anesthetist then increases the vaporizer to keep end-tidal 0.5 MAC until the surgery ends. An additional simulation shows that, compared with simulated end-tidal agent feedback control, this approach consumed 0.45 mL extra agent. Simulation results are the same for an 80-year-old patient. The extra 0.45 mL has a global warming potential comparable to driving 26 seconds at 40 kilometers (25 miles) per hour, comparable to route modification to avoid potential roadway hazards.

Comparing Perioperative Outcomes of Total Intravenous Anesthesia (TIVA) With Volatile Anesthesia in Patients With Obesity: A Systematic Review

In this systematic review, the perioperative outcomes of total intravenous anesthesia (TIVA) and volatile anesthesia were compared in obese adults (BMI ≥ 30 kg/m²) undergoing elective surgery. The review analyzed data from 12 randomized-controlled trials involving 935 patients, sourced from PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online), Cochrane, Scopus, and Web of Science databases. The focus was on intraoperative vital signs, emergence time, postoperative nausea and vomiting (PONV), duration of post-anesthesia care unit (PACU) stay, and ICU admission rates. Findings showed that TIVA (using propofol) might reduce PONV, but there were no significant differences in other outcomes compared to volatile anesthesia (with desflurane as the most common agent). The review highlights the need for more research, especially comparing sevoflurane with TIVA, to establish clear clinical guidelines for anesthesia in obese patients.

Total Intravenous Anesthesia Compared to Inhalational Anesthesia in Patients Undergoing Arthroscopic Rotator Cuff Repair

Background Inhalation anesthesia (IA) and total intravenous anesthesia (TIVA) are common general anesthesia techniques. During rotator cuff repair (RCR), an interscalene block is beneficial for intraoperative and early postoperative pain control. This study aimed to evaluate postoperative outcomes and opioid usage in patients undergoing arthroscopic RCR with an interscalene block and either IA or TIVA. Methodology A retrospective observational study was performed of 478 patients undergoing RCR at a single institution. Demographics, surgical details, intra and postoperative medications, and 90-day outcomes were collected. Univariate and multivariate analyses were performed to evaluate differences between groups. Results In total, 309 (64.6%) patients received IA and 169 (35.3%) received TIVA. Patients receiving IA were more likely to have comorbidities, such as diabetes (p = 0.002), sleep apnea (p = 0.006), gastroesophageal reflux disease (p < 0.001), and hypertension (p < 0.001). After adjusting for differences between groups in the multivariate analysis, patients who received TIVA had significantly shorter surgical time (β = -14.85, p < 0.001) and perioperative time (β = -21.01, p < 0.001) and significantly lower first post-anesthesia care unit Pasero opioid-induced sedation scores (β = -0.022, p = 0.040). Patients who received TIVA were less likely to receive intraoperative narcotics (odds ratio = 0.38; p = 0.031). Conclusions TIVA appears to be a safe and effective anesthetic for patients undergoing arthroscopic RCR. TIVA is a potentially beneficial alternative to IA for this patient population.

Recovery Benefit With Total Intravenous Anesthesia in Patients Receiving Rhinoplasty

OBJECTIVE

The aim was to evaluate the difference in recovery when comparing total intravenous anesthesia (TIVA) to inhalational gas anesthesia in patients receiving rhinoplasty.

STUDY DESIGN

Retrospective review.

SETTING

Postoperative anesthesia care unit (PACU).

METHODS

Patients who received a functional or cosmetic rhinoplasty at a single academic institution between April 2017 and November 2020 were included. Inhalational gas anesthesia was in the form of sevoflurane. Phase I recovery time, which was defined as the time it took a patient to reach ≥9/10 on the Aldrete scoring system was recorded, as well as the usage of pain medication in the PACU. The postoperative course and incidence of postoperative nausea and vomiting (PONV) were also collected.

RESULTS

Two hundred and two patients were identified with 149 (73.76%) who received TIVA and 53 (26.24%) who received sevoflurane. For the patients who received TIVA, the average recovery time was 101.44 minutes (standard deviation [SD]: 34.64) compared to an average recovery time of 121.09 minutes (SD: 50.19) for patients who received sevoflurane leading to a difference of 19.65 minutes (p = 0.002). Patients who received TIVA experienced less PONV (p = 0.001). There were no differences in the postoperative course including surgical or anesthesia complications, postoperative complications, hospital or Emergency Department admissions, or administration of pain medication (p > 0.05 for all).

CONCLUSION

When utilizing TIVA over inhalational anesthesia, patients undergoing rhinoplasty had significantly increased benefits in terms of reduced phase I recovery times and decreased incidence of PONV. TIVA was demonstrated to be a safe and efficacious method of anesthesia for this patient population.

The Potential Effect of General Anesthetics in Cancer Surgery: Meta-Analysis of Postoperative Metastasis and Inflammatory Cytokines

Metastasis or recurrence following curative surgery is the main indicator of tumor progress and is the main cause of patient death. For more than three decades, the potential for general anesthesia to affect cancer outcomes has been a subject of concern with considerable research interest. Here, we conducted this systematic review and meta-analysis to summarize the effect of inhalational anesthesia (IHNA) vs. propofol-based total intravenous anesthesia (TIVA) on metastasis and recurrence after cancer surgery from clinical and pre-clinical studies. The relative risk for metastasis/recurrence in TIVA is 0.61 (95% confidence interval (95% CI) 0.46 to 0.82, p = 0.0009) compared to IHNA. Inflammatory cytokines have been implicated in cancer metastasis following cancer surgery, thus we analyzed inflammatory cytokines levels after surgery under IHNA or TIVA. Based on pooled analysis, a lower IL-6 level was noticed in TIVA in comparison to IHNA (standardized mean difference (SMD) = 0.77, 95% CI = 0.097 to 1.44, I² = 92%, p = 0.02) but not TNF-α or IL-10. Preclinical animal model studies show that inhalational anesthetics increase the risk of breast cancer metastasis compared to propofol. In conclusion, the current evidence suggests intravenous anesthetic propofol is associated with less metastasis/recurrence and lower postoperative IL-6 level over inhaled anesthetics in the oncological surgery. We urge more well-designed clinical and preclinical studies in this field.

Total Intravenous Anesthesia Versus Inhaled Sevoflurane in Obstructive Sleep Apnea Surgery: A Randomized Controlled Trial

OBJECTIVE

Specific guidelines regarding an optimal general anesthesia (GA) approach to obstructive sleep apnea (OSA) patients remain undefined. Literature comparing the efficacy of total intravenous anesthesia (TIVA) and inhalational anesthesia in this population is sparse. We hypothesize that OSA patients receiving TIVA will experience reduced recovery times and other improved post-surgical outcomes.

STUDY DESIGN

Randomized controlled trial.

METHODS

Adult OSA patients undergoing upper airway surgery (hypoglossal nerve stimulation [HNS], nasal, or palate surgery) from February 2020-December 2020 were included. A post-anesthesia care unit (PACU) nursing survey documented patients' alertness, pain, oxygen supplementation, and postoperative nausea and vomiting from PACU arrival to 2 hours. Perioperative timepoints from the electronic medical record (EMR) and a nurse-estimated Phase I recovery time were collected.

RESULTS

One hundred eleven patients were included (46 TIVA and 65 inhalational anesthesia). Per EMR-recorded timepoints, TIVA patients undergoing HNS and palate surgery experienced Phase I Time reductions of 12.5 min (p = 0.042) and 27.5 min (p = 0.016), respectively. Per the PACU survey, TIVA patients undergoing any surgery, HNS, or palate surgery experienced nurse-estimated Phase I Time reductions of 16.5 min (p = 0.004), 12.5 min (p = 0.031), and 38.5 min (p = 0.024), respectively. Overall, TIVA patients experienced higher alertness and pain ratings, and lower oxygen supplementation requirements from PACU arrival to 30 min (p < 0.05).

CONCLUSION

Patients with OSA receiving TIVA for GA maintenance during upper airway procedures experienced reduced recovery times and oxygen supplementation requirements, and a more rapid return to alertness. Future work toward developing optimized anesthetic guidelines for OSA patients is merited.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:984-992, 2023.

Application of Propofol Target-Controlled Infusion for Optimized Hemodynamic Status in ESRD Patients Receiving Arteriovenous Access Surgery: A Randomized Controlled Trial

Background and Objectives: End-stage renal disease (ESRD) is associated with increased anesthetic risks such as cardiovascular events resulting in higher perioperative mortality rates. This study investigated the perioperative and postoperative outcomes in ESRD patients receiving propofol target-controlled infusion with brachial plexus block during arteriovenous (AV) access surgery. Materials and Methods: We recruited fifty consecutive patients scheduled to receive AV access surgery. While all patients received general anesthesia combined with ultrasound-guided brachial plexus block, the patients were randomly assigned to one of two general anesthesia maintenance groups, with 23 receiving propofol target-controlled infusion (TCI) and 24 receiving sevoflurane inhalation. We measured perioperative mean arterial pressure (MAP), heart rate, and cardiac output and recorded postoperative pain status and adverse events in both groups. Results: ESRD patients receiving propofol TCI had significantly less reduction in blood pressure than those receiving sevoflurane inhalation (p < 0.05) during AV access surgery. Perioperative cardiac output and heart rate were similar in both groups. Both groups reported relatively low postoperative pain score and a low incidence of adverse events. Conclusions: Propofol TCI with brachial plexus block can be used as an effective anesthesia regimen for ESRD patients receiving AV access surgery. It can be used with less blood pressure fluctuation than inhalational anesthesia.

Assessing Postoperative Recovery With Volatile Gas Versus Total Intravenous Anesthesia in Patients With and Without Obstructive Sleep Apnea

INTRODUCTION

To determine if there is a recovery time difference between patients with and without obstructive sleep apnea (OSA) when using total intravenous anesthesia (TIVA) compared to volatile gas inhalational anesthesia.

PATIENTS AND METHODS

OSA and Non-OSA patients were identified at a tertiary institution between January 2019 and November 2020. Non-OSA patients were defined as those who have not been formerly diagnosed with OSA. A modified STOP-BANG score (MSBS) was performed to screen Non-OSA patients for OSA. Recovery was measured by Phase I recovery time, or time it took a patient to reach ≥9/10 on the Aldrete scoring system.

RESULTS

A total of 334 patients were included with 142 in the OSA cohort (59 TIVA, 83 inhalational anesthesia) and 192 in the Non-OSA cohort (119 TIVA, 73 inhalational anesthesia). In OSA patients, there was a 41.29-minute recovery time reduction when using TIVA versus sevoflurane (P < .0001). Non-OSA patients recovered faster than OSA patients when undergoing inhalational anesthesia by 46.76 minutes and TIVA by 18.58 minutes (P < .0001 and P = .0907, respectively). Non-OSA patients with a MSBS < 3 and ≥3 had a shorter recovery time compared to OSA patients when both underwent sevoflurane anesthesia (57.27 minutes, P < .0001 and 56.23 minutes, P = .040, respectively). Non-OSA patients with a MSBS of <3 had a decrease in recovery time of 26.68 minutes when compared to OSA patients who underwent TIVA (P = .0004).

CONCLUSIONS

When utilizing TIVA over inhalational anesthesia, patients with OSA have significantly increased benefit in terms of reduced Phase I recovery times as compared to Non-OSA patients.

Ether Day Revisited: The Surgical Records of Edward Gilbert Abbott

Background

The details of the public demonstration of the effects of ether that initiated the modern era of surgery and anesthesia are often misreported. Existing published transcripts of the clinical records are incomplete or inaccurate.

Methods

The patient notes of Gilbert Abbott were photographed, transcribed, and reviewed.

Results

The records are handwritten in "Surgical Records for 1846; Volume 30," of the Massachusetts General Hospital. The patient was admitted on September 25. The presenting condition was a congenital, mobile, compressible, multilobed, small lesion at the angle of the left mandible, and base of tongue. The operation on October 16 was an attempted ligation of the blood supply to the lesion. The postoperative diagnosis was a vascular lesion ("erectile tumor"). Postoperative management included application of sclerosants. The mass was unchanged in size on discharge on December 7. There is no documentation of the anesthetic administration in the progress note but a retrospective report of the anesthetic is pasted into the Records book. This account reported that the patient did not respond to the initial incision. He moved and cried out during the latter part of the procedure. Although he was aware of the operation taking place, he later said he had not experienced pain. The commentary concluded that the demonstration of the analgesic effectiveness of ether was inconclusive but that subsequently ether was shown to be effective.

Conclusions

The surgery on October 16, an unsuccessful ligation of a congenital lymphovascular malformation, was performed under incomplete general anesthesia. Examination of the primary documents may allow for more accurate accounts of circumstances surrounding the discovery of anesthesia.

Incidence of Postoperative Cognitive Dysfunction Following Inhalational vs Total Intravenous General Anesthesia: A Systematic Review and Meta-Analysis

Postoperative cognitive dysfunction (POCD) has been increasingly recognized as a contributor to postoperative complications. A consensus-working group recommended that POCD should be distinguished between delayed cognitive recovery, ie, evaluations up to 30 days postoperative, and neurocognitive disorder, ie, assessments performed between 30 days and 12 months after surgery. Additionally, the choice of the anesthetic, either inhalational or total intravenous anesthesia (TIVA) and its effect on the incidence of POCD, has become a focus of research. Our primary objective was to search the literature and conduct a meta-analysis to verify whether the choice of general anesthesia may impact the incidence of POCD in the first 30 days postoperatively. As a secondary objective, a systematic review of the literature was conducted to estimate the effects of the anesthetic on POCD between 30 days and 12 months postoperative. For the primary objective, an initial review of 1913 articles yielded ten studies with a total of 3390 individuals. For the secondary objective, four studies with a total of 480 patients were selected. In the first 30 days postoperative, the odds-ratio for POCD in TIVA group was 0.46 (95% CI = 0.26-0.81; p = 0.01), compared to the inhalational group. TIVA was associated with a lower incidence of POCD in the first 30 days postoperatively. Regarding the secondary objective, due to the small number of selected articles and its high heterogeneity, a metanalysis was not conducted. Given the heterogeneity of criteria for POCD, future prospective studies with more robust designs should be performed to fully address this question.

Comparison of the effects of inhalational and total intravenous anesthesia on quality of recovery in patients undergoing endoscopic transsphenoidal pituitary surgery: a randomized controlled trial

Background: Endoscopic transsphenoidal pituitary surgery has shown promising results. However, fast and high-quality recovery after this procedure remains a challenge for neuroanesthesiologists. This study aimed to compare the quality of recovery after transsphenoidal pituitary surgery between patients who received inhalational anesthesia with sevoflurane and patients who received propofol-based total intravenous anesthesia (TIVA). Methods: Eighty-two patients undergoing transsphenoidal pituitary surgery were randomized to receive either sevoflurane inhalation with manual infusion of remifentanil (sevoflurane group) or effect-site target-controlled infusion of propofol and remifentanil (TIVA group). The primary outcome was the 40-item Quality of Recovery (QoR-40) score on postoperative day 1. The QoR-40 questionnaire was completed by patients the day before surgery and on postoperative days 1 and 2. Emergence agitation and recovery characteristics were also assessed. Results: There were no significant differences between the groups in the global QoR-40 scores on both postoperative days 1 and 2 (difference -8.7, 95% CI -18.0 to 0.7, and P = 0.204; -3.6, 95% CI -13.0 to 5.8, and P > 0.999, respectively). The time to verbal response and time to extubation were significantly shorter in the sevoflurane group than in the TIVA group (P < 0.001 and P < 0.001, respectively). However, the incidence of emergence agitation was lower in the TIVA group than in the sevoflurane group (P < 0.001). Conclusions: Both inhalational anesthesia with sevoflurane and propofol-based TIVA were appropriate anesthetic techniques for patients undergoing endoscopic transsphenoidal pituitary surgery in terms of the quality of recovery up to 2 days postoperatively. Rapid emergence was observed in the sevoflurane group, while smooth emergence was observed in the TIVA group.

The hypoxic pulmonary vasoconstriction: From physiology to clinical application in thoracic surgery

More than 70 years after its original report, the hypoxic pulmonary vasoconstriction (HPV) response continues to spark scientific interest on its mechanisms and clinical implications, particularly for anesthesiologists involved in thoracic surgery. Selective airway intubation and one-lung ventilation (OLV) facilitates the surgical intervention on a collapsed lung while the HPV redirects blood flow from the "upper" non-ventilated hypoxic lung to the "dependent" ventilated lung. Therefore, by limiting intrapulmonary shunting and optimizing ventilation-to-perfusion (V/Q) ratio, the fall in arterial oxygen pressure (PaO₂) is attenuated during OLV. The HPV involves a biphasic response mobilizing calcium within pulmonary vascular smooth muscles, which is activated within seconds after exposure to low alveolar oxygen pressure and that gradually disappears upon re-oxygenation. Many factors including acid-base balance, the degree of lung expansion, circulatory volemia as well as lung diseases and patient age affect HPV. Anesthetic agents, analgesics and cardiovascular medications may also interfer with HPV during the perioperative period. Since HPV represents the homeostatic mechanism for regional ventilation-to-perfusion matching and in turn, for optimal pulmonary oxygen uptake, a clear understanding of HPV is clinically relevant for all anesthesiologists.

Sevoflurane and Desflurane Exposures Following Aneurysmal Subarachnoid Hemorrhage Confer Multifaceted Protection against Delayed Cerebral Ischemia

Numerous studies have demonstrated the ability of isoflurane conditioning to provide multifaceted protection against aneurysmal subarachnoid hemorrhage (SAH)-associated delayed cerebral ischemia (DCI); however, preclinical studies have not yet examined whether other commonly used inhalational anesthetics in neurological patients such as sevoflurane or desflurane are also protective against SAH-induced neurovascular deficits. We therefore sought to identify the potential for sevoflurane and desflurane conditioning to protect against DCI in an endovascular perforation mouse model of SAH. Neurological function was assessed daily via neuroscore. Large artery vasospasm and microvessel thrombosis were assessed three days after SAH or sham surgery. Four groups were examined: Sham, SAH + room air, SAH + 2% Sevoflurane, and SAH + 6% Desflurane. For the SAH groups, one hour after surgery, mice received 2% sevoflurane, 6% desflurane, or room air for one hour. We found that conditioning with sevoflurane or desflurane attenuated large artery vasospasm, reduced microvessel thrombosis, and improved neurologic function. Given their frequent clinical use and strong safety profile in patients (including those with SAH), these data strongly support further studies to validate these findings in preclinical and clinical studies and to elucidate the mechanisms by which these agents might be acting.

Predicting cost of inhalational anesthesia at low fresh gas flows: impact of a new generation carbon dioxide absorbent

It is well known that low fresh gas flows result in lower cost of inhalational agents. A new generation of carbon dioxide absorbents allows low flow anesthesia with all anesthetics but these new compounds are more expensive. This study examines the cost of inhalational anesthesia at different fresh gas flows combined with the cost of absorbent. The cost of sevoflurane and desflurane is lower at low fresh gas flows. Paradoxically the cost of isoflurane is cheaper at 2 L/min than at lower fresh gas flows due to increased cost of carbon dioxide absorbent. Therefore low fresh gas flows should be used when feasible with sevoflurane and desflurane, but higher fresh gas flows up to 2 L/min may be more economical with isoflurane during maintenance phase of anesthesia.

Which Anesthesia Regimen Is Best to Reduce Pulmonary Complications After Head and Neck Surgery?

OBJECTIVES/HYPOTHESIS

The differences between intravenous and inhalation anesthesia in clinical postoperative pulmonary complications (PPCs) have been studied in cardiac and lung resection surgery. Clinical evidence for the effects of these two anesthetics on PPCs in other types of surgery is still missing. We aimed to assess the impact of sevoflurane and propofol on the incidence of PPCs in patients undergoing surgery for head and neck cancer.

STUDY DESIGN

Double-blind, randomized, controlled trial.

METHODS

We assigned 220 adults at intermediate-to-high risk of PPCs scheduled for head and neck cancer surgery with radial forearm or fibular flap reconstruction to either propofol or sevoflurane as a general anesthetic. The occurrence of pulmonary complications according to the Clavien-Dindo score was defined as the primary (within 7 days after surgery) outcome.

RESULTS

The PPC incidence during 7 days after surgery was 32.4% and 18.2% in the propofol and sevoflurane groups, respectively (P = .027). The corresponding incidence of PPCs in patients who underwent tracheotomy at the end of surgery in the two groups was 44.8% and 24.5%, respectively (P = .030). In addition, the Clavien-Dindo classification showed significant differences between groups in minor complications (grades I and II) but not in major complications (grades III-V).

CONCLUSIONS

Compared with intravenous anesthesia, the administration of sevoflurane reduces the incidence of minor PPCs (grades I and II) in moderate- and high-risk patients who have undergone tracheotomy after head and neck cancer surgery with radial forearm or fibular flap reconstruction.

LEVEL OF EVIDENCE

2 Laryngoscope, 131:E108-E115, 2021.

Survey of anesthesiologists on anesthetic maintenance techniques and total intravenous anesthesia for endoscopic sinus surgery

BACKGROUND

Inhalational anesthesia and total intravenous anesthesia (TIVA) are techniques used for maintenance of general anesthesia for endoscopic sinus surgery (ESS). Growing evidence exists that TIVA may be associated with decreased bleeding and improved surgical fields, yet data suggest it is used in a minority of sinus surgery cases. The objective of this study was to investigate perceptions and approaches to anesthetic maintenance techniques in ESS among anesthesia providers.

METHODS

A total of 719 anesthesiology residents, faculty, and certified registered nurse anesthetists (CRNAs) at 3 tertiary academic centers in the United States were invited to participate in a survey of considerations and practice patterns for inhalational anesthesia and TIVA for ESS.

RESULTS

Responses were received from 200 participants (28%). Sixty-five percent of respondents reported a lack of familiarity with current literature on TIVA for ESS. Many considered factors other than surgical field visualization when choosing a maintenance technique. Most were comfortable with performing TIVA but stated they would participate in additional training.

CONCLUSION

The majority of anesthesiology providers were unaware of the existing literature demonstrating advantage in improved surgical visualization with TIVA. Many used a combination of inhaled and intravenous anesthetics for maintenance. These findings suggest that future opportunities may exist to develop education, training, and practice approaches specific to anesthetic techniques for ESS.

The choice of the hypnotic drug (volatile or propofol) for maintenance of anesthesia does not influence surgical conditions during cranioplasty

Background and Aims:

In contrast to propofol, volatile agents are often considered harmful to maintain anesthesia due to increasing brain volume and potential deleterious effects. Patients for cranioplasty, including patients with large bone defects, could be susceptible for intraoperative complications but have not properly been investigated so far. The aim of the present study was to evaluate brain swelling, intraoperative conditions, surgical course, and postoperative complication rates of propofol-based vs. volatile-based anesthesia.

Material and Methods:

In this monocentric, retrospective, and observational study, we collected demographic, clinical, and outcome data of patients undergoing cranioplasty between December 2010 and September 2014. According to the hypnotic drug used, patients were assigned to either a propofol or a volatile group. The primary outcome parameter was brain swelling. For comparison of the groups, univariate analysis was performed using Chi-square and Mann–Whitney-U test.

Results:

One hundred and one patients were identified in the period. Twenty-three patients were excluded due to cerebrospinal fluid diversion. Baseline characteristics and preoperative conditions did not vary between the groups except a higher body mass index and positive end-expiratory pressure (PEEP) in the propofol group. The choice of anesthesia (volatile or intravenous) influence neither the intraoperative local conditions nor postoperative complication rate. No significant risk factor for impaired bone flap placement was identified.

Conclusions:

In a well-defined cohort, the choice of the anesthetic agent does not influence the degree of intraoperative brain swelling, bone flap fit, and postoperative course.

Effects of propofol anesthesia versus sevoflurane anesthesia on postoperative pain after radical gastrectomy: a randomized controlled trial

Purpose

After a radical gastrectomy, patients may experience severe pain. Some studies have reported that the use of propofol significantly reduced postoperative pain, while others have argued that this effect was not significant. Thus, we aimed to assess whether anesthesia with propofol could help to reduce pain after an open radical gastrectomy procedure.

Patients and methods

Sixty patients who were scheduled to undergo a laparotomy for radical gastrectomy were randomly assigned to either the propofol or sevoflurane group (n=30 each). A target-controlled infusion of propofol or inhalation of sevoflurane, titrated to bispectral index of 40–60, was maintained. All patients were administered a standardized multimodal analgesic plan, including intraoperative dexmedetomidine, dexamethasone, and postoperative flurbiprofen axetil, as well as patient-controlled fentanyl. Hemodynamics, pain scores, fentanyl consumption, adverse events, and the incidence of chronic pain 1 month and 3 months following hospital discharge were recorded.

Results

The intensity of postoperative pain was relatively low to moderate in all the patients. The propofol group showed lower pain scores, at rest and while coughing, up to 48 h postoperatively compared to the sevoflurane group (P<0.05). Cumulative fentanyl consumption 0–24 h after surgery was lower for the propofol group (364.4 ± 139.1 vs. 529.3 ± 237.9 µg; P=0.002). However, for fentanyl consumption 0–48 h, the difference between the two groups was not significant (710.9 ± 312.8 vs. 850.9 ± 292.0 µg; P=0.078). There were no differences in the incidences of adverse events or chronic pain between the groups.

Conclusions

Overall, the multimodal analgesic approach reduced postoperative pain after an open radical gastrectomy procedure in all patients anesthetized with either propofol or sevoflurane. Furthermore, our results indicated better analgesic outcome for the propofol group, especially in the early postoperative period.

Sevoflurane may be more beneficial than propofol in patients receiving endoscopic variceal ligation and endoscopic variceal sclerotherapy: A randomized, double-blind study

The aim of the present study was to evaluate the safety and efficacy of various general anesthesia regimens during endoscopic variceal ligation (EVL) and endoscopic variceal sclerotherapy (EVS). A total of 123 patients with American Society of Anesthesiologists physical status III and IV, aged 40-70 years, undergoing general anesthesia for EVL and EVS were randomly divided into two groups: Sevoflurane anesthesia (group S; n=60) and propofol anesthesia (group P; n=60). Vital signs, particularly heart rate (HR) and mean arterial pressure (MAP), were monitored. The designated time points were as follows: 5 min before induction (T0), and 1, 5, 10, 15, 20, 25 and 30 min after intubation (T1, T2, T3, T4, T5, T6 and T7, respectively). Time intervals were recorded, including recovery time and extubation time. Following surgery, the observer recorded the Ramsay sedation scale (RSS) score and the visual analogue scale (VAS) score. Adverse reactions were noted. Results demonstrated that there were significant differences in MAP between the two groups at T2, T3, T5, T6 and T7 (P<0.05). There was a significant difference in HR between the two groups at T2, T3 and T4 (P<0.05). Recovery time and extubation time in group P were significantly longer than those in group S (P<0.05; 18.38±2.25 min vs. 14.57±1.04 min and 21.70±2.70 min vs. 15.83±0.88 min, respectively). The rate of ephedrine injected was 58.3% (35/60 patients) in group P vs. 28.3% (17/60 patients) in group S (P<0.05). There was a significant difference in the RSS score between the two groups 5 min after extubation (P<0.05). VRS scores demonstrated that anesthetists and patients were significantly more satisfied with the procedure in group S than in group P (P<0.01). In conclusion, the superiority and special clinical value of inhalational anesthesia has been demonstrated during EVL and EVS attributed to stable hemodynamics and high quality of anesthesia recovery in the present study.

A Study to Compare the Quality of Surgical Field Using Total Intravenous Anesthesia (with Propofol) versus Inhalational Anesthesia (with Isoflurane) for Functional Endoscopic Sinus Surgeries

Background and Objectives:

Functional endoscopic sinus surgery (FESS) being a delicate technique, intraoperative bleeding is one of the major challenges. Even a little bleeding can adversely affect the surgeon's ability to visualize the region to be operated. General anesthesia is preferred over topical anesthesia in FESS. This study was conducted to compare the surgical field using total intravenous anesthesia (TIVA) with propofol and inhalational anesthesia with isoflurane for FESS. Secondary outcomes such as intraoperative blood loss and the incidence of perioperative complications were also recorded.

Subjects and Methods:

A total of sixty patients in the age group of 16–60 years with physical status American Society of Anesthesiologists Classes I and II, undergoing FESS were randomly divided into two groups of thirty each after taking informed consent and approval from the Hospital Ethics Committee. Thirty patients in Group I: received isoflurane-based inhalational anesthesia and other Thirty patients in Group II: were administered TIVA with propofol. Various parameters were recorded and statistically analyzed.

Results:

There was improved quality of surgical field at the end of surgery in the Group II as compared to Group I. Total blood loss during surgery and incidence of intraoperative complications were less in Group II as compared to Group I.

Conclusion:

This study concludes that in FESS, using TIVA with propofol decreases blood loss and the incidence of complications during surgery in addition to providing good quality of surgical field.

In vivo field recordings effectively monitor the mouse cortex and hippocampus under isoflurane anesthesia

Isoflurane is a widely used inhaled anesthetic in the clinical setting. However, the mechanism underlying its effect on consciousness is under discussion. Therefore, we investigated the effect of isoflurane on the hippocampus and cortex using an in vivo field recording approach. Our results showed that 1.3%, 0.8%, and 0.4% isoflurane exerted an inhibitory influence on the mouse hippocampus and cortex. Further, high frequency bands in the cortex and hippocampus showed greater suppression with increasing isoflurane concentration. Our findings suggest that in vivo field recordings can monitor the effect of isoflurane anesthesia on the mouse cortex and hippocampus.

Cost efficiency of target-controlled inhalational anesthesia

BACKGROUND

Cost and environmental pollution are two prime concerns with general anesthesia. We hypothesized that target-controlled (TC) anesthesia drug delivery system also called as end-tidal (ET) control is an effective and safe system that would reduce the cost and also environmental pollution.

MATERIALS AND METHODS

We studied 200 patients undergoing laparoscopic abdominal and pelvic surgeries and randomly distributed those in 2 groups of 100 each, TC and manual-controlled (MC) group. We reviewed the two groups in term of consumption of gases, time required to achieve the ET concentration of sevoflurane of 1.5%, maximum inspired concentration of sevoflurane achieved, and number of adjustments required to maintain the depth of anesthesia.

RESULTS

We found that the consumption of nitrous oxide and sevoflurane was significantly less in TC group than MC group (P < 0.05), oxygen consumption was also less in TC group but not statistically significant. The time required to achieve the desired levels, maximum inspired sevoflurane concentration achieved, and the number of drug delivery adjustments required were statistically significant in TC group (P < 0.05). As the consumption reduced in TC group, the cost of the inhalational anesthesia reduced by approximately Rs. 64/h ($1.12) and thus the environmental pollution.

CONCLUSION

We concluded from our study that ET control is a good system for conserving the consumption of gases and thus is efficient as it reduces both the cost and the environmental pollution.

Systematic review and meta-analysis of total intravenous anesthesia and endoscopic sinus surgery

BACKGROUND

Total intravenous anesthesia (TIVA) has been shown in some studies to impact visual field, blood loss, and cardiovascular parameters during endoscopic sinus surgery when compared to inhalational anesthesia (IA). These variables are critical in endoscopic sinus surgery. A systematic review and meta-analysis was undertaken to discern the impact of TIVA vs IA in endoscopic sinus surgery.

METHODS

MEDLINE (1950 to October 20, 2012) was searched using a search strategy designed to include all randomized controlled trials (RCTs) that discussed TIVA, IA, and endoscopic sinus surgery. An abstract search was then used to identify RCTs directly comparing TIVA and IA in endoscopic sinus surgery. All articles selected then underwent full-text review. Data on visual field scores, blood loss, and cardiovascular parameters was then extracted, compared, and analyzed.

RESULTS

There were 42 articles identified by the search strategy. Full-text review identified 9 articles that met eligibility criteria and contained extractable data. Although inconsistently reported, preoperative characteristics (Lund-Mackay scores and history of nasal polyps) were similar (p > 0.05) between the 2 groups. No difference was found between heart rate, mean arterial pressure, anesthesia time, operative time, or estimated blood loss. Only 7 studies reported a visibility score, but overall favored the TIVA group (p < 0.001).

CONCLUSION

Current evidence supporting TIVA is limited to a handful of inconsistently controlled and reported studies. Standardized grading of visibility scores and preoperative characteristics would better establish the role of TIVA in endoscopic sinus surgery.

Effects of isoflurane anesthesia on the cardiovascular function of the C57BL/6 mouse

Isoflurane (ISO) is the most commonly used inhalational anesthetic for experimental interventions in mice and is preferred for imaging technologies that require the mouse to remain anesthetized for relatively long time periods. This study compares the stability of mean arterial pressure (MAP), heart rate (HR), and body temperature under ISO concentrations of 1%, 1.5%, and 2% (volume-to-volume, v/v) for up to 90 minutes postinduction. At all three levels of anesthesia, we examined evoked physiological responses to fractional inspiratory ratio variations of oxygen (FiO2) and nitrous oxide (N2O). In addition, we determined the hemodynamic effects of anesthesia on pH, glucose, insulin, glucocorticoids, and partial pressure of oxygen and of carbon dioxide in the blood (paO2, paCO2). The results indicate that the most appropriate ISO dose level was 1.5% v/v, yielding stable MAP and HR values comparable to those observed in the animal's conscious state, with a minute-to-minute variability in MAP and HR of .11%. Based on such recordings, the optimal FiO2 appeared to be 50%. The additional use of N2O was associated with higher and more stable values of MAP and HR. Arterial pH values were within the physiological range and varied between 7.20 and 7.43. ISO anesthesia at 1.5% v/v was also associated with mild hyperglycemia (+47%), whereas insulin levels and corticosteroids remained unaltered. We conclude that the application of isoflurane as an inhalational anesthetic in the mouse can be optimized to attain stable hemodynamics by administering it at 1.5% v/v and by supplementing it with N2O.

Inhalational anesthetics as neuroprotectants or chemical preconditioning agents in ischemic brain

This review will focus on inhalational anesthetic neuroprotection during cerebral ischemia and inhalational anesthetic preconditioning before ischemic brain injury. The limitations and challenges of past and current research in this area will be addressed before reviewing experimental and clinical studies evaluating the effects of inhalational anesthetics before and during cerebral ischemia. Mechanisms underlying volatile anesthetic neuroprotection and preconditioning will also be examined. Lastly, future directions for inhalational anesthetics and ischemic brain injury will be briefly discussed.