Awareness during general anesthesia: An Indian viewpoint

The Effect of Anaesthesia Management with Different Fresh Gas Flows on Cognitive Functions of Geriatric Patients: A Randomized Double-blind Study

Objective

The present study aimed to compare the effects of two different fresh gas flows (FGFs) (0.5 L min^-1 and 2 L min^-1) applied during maintenance of anaesthesia on recovery from anaesthesia and early cognitive functions in geriatric patients.

Methods

In this prospective, randomised, double-blind study, sixty patients were divided into two groups according to the amount of FGF. Minimal-flow anaesthesia (0.5 L min^-1 FGF) was applied to group I and medium-flow anaesthesia (2 L min^-1 FGF) was applied to group II during maintenance of anaesthesia. Following the termination of inhalation anaesthesia, recovery times were recorded. The evaluation of cognitive functions was performed using the Addenbrooke's Cognitive Examination (ACE-R).

Results

There was no significant difference between the two groups in terms of demographic characteristics and recovery (P > 0.05). There was no significant difference between the two groups in terms of the preoperative day, the first postoperative day, and the third postoperative day; ACE-R scores (P > 0.05). In group II, on the third postoperative day ACE-R scores were found to be significantly lower than the preoperative ACE-R scores (P=0.04). In group II, third postoperative day ACE-R memory sub-scores (14.53 ± 3.34) were found to be significantly lower than preoperative ACE-R memory sub-scores (15.03 ± 3.57) (P=0.04).

Conclusion

In geriatric patients, minimal-flow anaesthesia was not superior to medium-flow anaesthesia in terms of recovery properties and cognitive functions. Keeping in mind that hypoxaemia and changes in anaesthesia levels may occur with the reduction of FGF, both minimal- and medium-flow anaesthesia can be applied with appropriate monitoring without adverse effects on recovery and cognitive functions.

Awareness Among the Patients Under General Anesthesia: A Cross-Sectional Study

Introduction Unless specifically asked, many patients may be hesitant to discuss their experiences. Some people might not recall what happened right after surgery, but they might remember it 1-2 weeks later. We undertook the current study to estimate the incidence of awareness among patients under general anesthesia (GA). Methodology We conducted a cross-sectional, analytical study for three months. The study included patients who underwent functional endoscopic sinus surgery (FESS), septoplasty, mastoidectomy, or laparoscopic appendicectomy under general anesthesia. Patients who refused to take part and had low Glasgow Coma Scale (GCS) scores (less than 9) or didn't meet extubation criteria were all excluded from the study. We used a pre-validated semi-structured questionnaire for data collection. It had two sections. The first one includes demographic details, and the second section contains the modified Brice questionnaire. By using this questionnaire, we classified the patients as A, B, and C. Class A experiences are those that were remembered under anesthesia or surgery and were confirmed or disproved by the attending medical personnel present in the operating room. Class B, which stands for "potential awareness," was defined as a state in which the patient could not specifically recollect any occurrence that occurred during anesthesia or surgery but could have made connections between memories and the surgical procedure. We define Class C as a lack of recalled intraoperative events with probable memories of scenarios from the immediate pre- or postoperative period. We analyzed the data collected using IBM Corp. Released 2012. IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp.  Results About 240 patients took part in this study. Most of the people (68%) were men in the age group of 31 to 50 years. About 2% of the patient's experience awareness during general anesthesia. Only 2.5% of patients experienced dreaming. The association between awareness and comorbidity was statistically significant (P < 0.001). Conclusion It is about to know that our study results suggest that awareness had an association with comorbidity among the patients undergoing surgery under general anesthesia.

Variations in Values of State, Response Entropy and Haemodynamic Parameters Associated with Development of Different Epileptiform Patterns during Volatile Induction of General Anaesthesia with Two Different Anaesthetic Regimens Using Sevoflurane in Comparison with Intravenous Induct: A Comparative Study

BACKGROUND AND OBJECTIVES

Raw electroencephalographic (EEG) signals are rarely used to monitor the depth of volatile induction of general anaesthesia (VIGA) with sevoflurane, even though EEG-based indices may show aberrant values. We aimed to identify whether response (RE) and state entropy (SE) variations reliably reflect the actual depth of general anaesthesia in the presence of different types of epileptiform patterns (EPs) in EEGs during induction of general anaesthesia.

MATERIALS AND METHODS

A randomized, prospective clinical study was performed with 60 patients receiving VIGA using sevoflurane with the increasing concentrations (group VIMA) or the vital capacity (group VCRII) technique or an intravenous single dose of propofol (group PROP). Facial electromyography (fEMG), fraction of inspired sevoflurane (FiAA), fraction of expired sevoflurane (FeAA), minimal alveolar concentration (MAC) of sevoflurane, RE and SE, and standard electroencephalographic evaluations were performed in these patients.

RESULTS

In contrast to periodic epileptiform discharges, erroneous SE and RE values in the patients' EEGs were associated with the presence of polyspikes (PS) and rhythmic polyspikes (PSR), which were more likely to indicate toxic depth rather than false emergence from anaesthesia with no changes in the FiAA, FeAA, and MAC of sevoflurane.

CONCLUSION

Calculated RE and SE values may be misleading during VIGA when EPs are present in patients' EEGs. During VIGA with sevoflurane, we recommend monitoring raw EEG data in scientific studies to correlate it with potentially erroneous RE and SE values and the end-tidal concentration of sevoflurane in everyday clinical practice, when monitoring raw EEG is not available, because they can mislead anaesthesiologists to reduce sevoflurane levels in the ventilation gas and result in unintentional true emergence from anaesthesia. Further studies are required to investigate the behaviour of EEG-based indices during rapid changes in sevoflurane concentrations at different stages of VIGA and the influence of polyspikes and rhythmic polyspikes on the transformation of EEG signals into a digital form.

The Study of Intraoperative Consciousness after Tracheal Intubation

Introduction

Awareness following noxious stimuli like intubation could be as high as 25% compared to postoperative recall. The isolated forearm technique (IFT) allows us to assess consciousness by verbal command to move isolated hand. Hence we conducted study to establish IFT responses following intubation under standard general anaesthesia.

Methods

We enrolled 132 adult patients undergoing general anaesthesia. A tourniquet was applied on other arm. Following intravenous induction of anaesthesia, torniquet was inflated 100mmhg above systolic BP. After giving muscle relaxant, three minutes patients were ventilated with oxygen and inhalational agent. Before laryngoscopy first verbal command (Squeeze my hand) was given to the patient. Once intubation and tube confirmation done, second verbal command was given. Lack of paralysis in isolated hand was confirmed with TOF stimuli and tourniquet was deflated. Surgery was carried in routine manner. Postoperatively all patients were evaluated for any explicit recall using Modified Brice questionnaire. The primary outcome is number of patients who responded to verbal command postintubation. Secondary outcome is number of patients responded prelaryngoscopy and number of patients reporting explicit recall in the Modified Brice interview.

Results

None of the patients had positive IFT response. On postoperative interview none reported awareness. 10.7% of patients had dreams which were pleasant. Worst thing about surgery was pain.(43%).

Conclusion

Our study suggests that intraoperative consciousness after intubation and postoperative recall is an uncommon occurrence.

Incidence of Awareness with Recall under General Anesthesia in Rural India: An Observational Study

Context:

Awareness under anesthesia is a rare but extremely unpleasant phenomenon. There are very few studies in the developing world and none from rural areas where incidence of intraoperative awareness may be higher due to increased patient load, limited patient knowledge and lack of trained hospital staff, reliance on older, cheaper but less effective drugs, and lack of proper equipment both for providing anesthesia, as well as monitoring the patient.

Aims:

To assess the incidence of intraoperative awareness during general anesthesia among patients in rural India and any factors associated with the same.

Settings and Design:

Prospective, nonrandomized, observational study.

Subjects and Methods:

Patients undergoing elective surgical procedures in various specialties under general anesthesia from over a period of 1 year were considered for this study. Approximately, after 1 h of arrival in postanaesthesia care unit, anesthesiologist (not involved in administering anesthesia) assessed intraoperative awareness using a modified form of Brice questionnaire.

Statistical Analysis Used:

Data were collected on a Microsoft Excel^® sheet and analyzed using Statistical Package for the Social Sciences^® version 23 (SPSS Inc., Chicago, IL, USA) for windows.

Results:

A total of 896 patients completed the questionnaire. Postoperatively, in response to the questionnaire, seven patients reported to have remembered something under anesthesia. Out of these, three patients described events that were confirmed by operation theater staff to have occurred whereas they were under anesthesia.

Conclusions:

Incidence of definite awareness under anesthesia with postoperative recall was found to be 0.33% (three patients out of total 896) in our study.

An observational study on patient admission in the anaesthesia gas monitor and minimum alveolar concentration monitoring: A deficiency with huge impact

Background and Aims:

Minimum alveolar concentration (MAC) monitoring is an integral part of modern-day anaesthesia. Both MAC and MAC-awake are age dependant, and age of the patient needs to be entered in the monitor. This study was aimed to assess the practice of patient birth year entry in the anaesthesia monitor and its impact on MAC monitoring.

Methods:

Sixty volatile anaesthetic-based general anaesthetics (GAs) were observed silently in two tertiary care teaching hospitals with regard to ‘birth year’ entry in the patient monitor. The impact on MAC for non-entry of age was assessed. The observed MAC reading and the MAC corrected for age (MAC_age) of the patients were noted. Paired t-test was used to compare the differences in observed MAC and MAC_age values. P <0.05 was significant.

Results:

Sixty GAs of patients aged between 10 and 68 years were observed; 96.67% anaesthetics were conducted without entering ‘birth year’. Thirty-four patients (mean age 35.14 ± 15.38 years) were further assessed for impact of non-entry of age. The observed MAC was similar to MAC_age in patients aged 40 ± 5 years (36–45 years group). Nearly 79.41% of the observed MACs were incorrect; 55.88% patients were potentially underdosed whereas 23.53% were overdosed.

Conclusion:

Omitting patient age entry in the monitor results in erroneous MAC values, exposing patients <40 years to underdosing and older patients to overdose.