To dimerize or not: para-aminothiophenol on a bismuth heterostructure.

Surface enhanced Raman spectroscopy (SERS) of p-aminothiophenol (PATP) was investigated on ß-Bi2O3/Bi2O2CO3 nanoparticles, a novel bismuth based metal substrate with the lowest limit of detection of 1 mM. Unlike on noble metal surfaces where PATP gets converted to p,p'-dimercaptoazobenzene (DMAB) due to photocatalytic coupling, no such transformation of PATP was observed on ß-Bi2O3/Bi2O2CO3 nanoparticles. Density functional theory (DFT) calculations at the PW91PW91/LANL2DZ/6-311+G(d,p) level of theory supported the experimental results exceedingly well. Also, the charge transfer direction from PATP to ß-Bi2O3/Bi2O2CO3 nanoparticles was revealed by the projected density of states calculation.

Sulfur Centered Hydrogen Bonding in Thioglycolic Acid and Its Clusters: A Computational Exploration.

The conformational landscape of thioglycolic acid (TGA) was investigated by using the CCSD/cc-pVTZ level of theory. The GGC conformer was identified as the global minimum, followed by the GAC conformer. The calculated rotational constant for the GGC conformer exhibited good agreement with the previously reported experimental results. Subsequently, the study delved into the exploration of sulfur-centered hydrogen bonding in TGA's dimer and trimer clusters, employing the CCSD/cc-pVDZ level of theory. These clusters revealed the participation of both oxygen and sulfur atoms in noncovalent H-bonding, contributing to their stability. The presence of these noncovalent interactions in TGA clusters was elucidated through Atoms in Molecule (AIM), reduced density gradient (RDG), and natural bond order (NBO) analysis, while electrostatic potential (ESP) charge and vibrational mode analysis further supported these findings.

Fiber-optic Bronchoscope-guided vs Mini-surgical Technique of Percutaneous Dilatational Tracheostomy in Intensive Care Units.

BACKGROUND: Percutaneous dilatational tracheostomy (PCDT) using fiber-optic bronchoscope (FOB) is a widely practiced technique, but its availability and cost remain a concern in nations with limited resources. Mini-surgical technique of PCDT incorporating minimal blunt dissection has shown improved results even without the use of FOB. The study is primarily intended to compare these two techniques and establish a safer cost-effective alternative to FOB-guided PCDTs. PATIENTS AND METHODS: This randomized comparative study [registered (CTRI/2018/04/013191)] was conducted on 120 mechanically ventilated patients. In 60 patients, mini-surgical PCDT (group-M) was performed with 2 cm longitudinal skin incision and blunt dissection till pretracheal fascia without FOB guidance using Portex-Ultraperc™ sets. In remaining 60 patients, PCDT was performed under FOB vision with similar skin incision (without blunt dissection) using Portex-Ultraperc™ sets (group-F). Two techniques were compared with regard to procedural time and percentage of complications occurred during or after the procedure. RESULTS: Procedure time [group-M: 6.30 ± 1.28 minutes; group-F: 14.43 ± 1.84 minutes (p <0.001)] and mean blood loss [group-M: 5.33 ± 1.69 mL; group-F: 6.87 ± 3.11 mL (p = 0.001)] was significantly less in group-M. Higher incidence of desaturation [group-M: 16.7%; group-F: 35% (p = 0.022)] was noted in group-F, whereas arrhythmias [group-M: 21.7%; group-F: 6.7% (p = 0.018)] were higher in group-M. There was no statistical difference in incidence of pneumothorax and subcutaneous emphysema. There was no incidence of posterior tracheal wall perforation in any of the patients. CONCLUSION: Mini-surgical technique is a faster alternative of FOB-guided PCDT with comparable incidence of complications. It can safely be used in intensive care units (ICUs) where FOB is not available. CLINICAL TRIAL REGISTRATION NUMBER: CTRI/2018/05/014307. NAME OF REGISTRY: Clinical Trials Registry of India (CTRI), URL-http://ctri.nic.in. HOW TO CITE THIS ARTICLE: Kumar A, Kohli A, Kachru N, Bhadoria P, Wadhawan S, Kumar D. Fiber-optic Bronchoscope-guided vs Mini-surgical Technique of Percutaneous Dilatational Tracheostomy in Intensive Care Units. Indian J Crit Care Med 2021;25(11):1269-1274.

Comparative evaluation of dexmedetomidine and fentanyl in total intravenous anesthesia for laparoscopic cholecystectomy: A randomised controlled study.

BACKGROUND AND AIMS: Laparoscopic cholecystectomy is one of the commonly performed ambulatory surgeries. The selection of anesthetic agents for ambulatory surgeries should be done bearing in mind the need for early discharge. Opioids form an integral component of total intravenous anesthesia (TIVA) but their associated side effects may result in an increased hospital stay. Hence, we planned a study to compare the opioid (fentanyl) and non-opioid (dexmedetomidine) based technique of TIVA for laparoscopic surgery. MATERIAL AND METHODS: Ninety ASA I and II patients between 18-60 years of either sex posted for laparoscopic cholecystectomy were randomly allocated into two groups namely group D (Dexmedetomidine) and group F (Fentanyl). Patients received propofol infusion along with group specific drug infusion, after which an appropriate size proseal laryngeal mask airway was placed. The patients were assessed for discharge time from post-anesthesia care unit (PACU), on table recovery time, time to first rescue analgesia, hemodynamic parameters, incidence of postoperative nausea and vomiting (PONV) and any other complication. RESULTS: Demographic profile of both the groups was comparable. Group D had longer on table recovery time (13.00 ± 2.34 min vs 6.29 ± 2.46 min; P < 0.001) and time to discharge from PACU (6.80 ± 3.96 min vs 2.36 ± 1.67 min; P < 0.001) compared to group F. Group F had better hemodynamic stability compared to group D. In group D, 77% patients required rescue analgesia in first one hour post surgery, unlike 22% in group F. No patient in group D had PONV. CONCLUSION: Opioid based technique (Fentanyl) of TIVA is superior over non-opioid based (dexmedetomidine) technique with faster recovery, early discharge, decreased postoperative pain scores and better hemodynamic stability. PONV is observed with opioids which can be treated successfully with antiemetics.

Comparative evaluation of I-gel vs. endotracheal intubation for adequacy of ventilation in pediatric patients undergoing laparoscopic surgeries.

BACKGROUND AND AIMS: The use of newer supraglottic devices has been extended to laparoscopic procedures. We conducted this study to compare and evaluate the efficacy of these two devices in pediatric laparoscopic surgeries. MATERIAL AND METHODS: Eighty children, 2-8 years of age, scheduled for elective short laparoscopic procedures were randomly allocated to the I-gel or endotracheal tube (ETT) group. Standard anesthesia protocol was followed for inhalational induction. I-gel or ETT was inserted according to the manufacturer's recommendations. Ventilation was set with tidal volume 10 ml/kg and a respiratory rate of 16/min. Carboperitoneum was achieved up to an intra-abdominal pressure of 12 mmHg. STATISTICAL ANALYSIS: The primary outcome variable was adequacy of ventilation (peak airway pressure, end-tidal CO2, minute ventilation, and SPO2). These variables were recorded after securing airway, after carboperitoneum and desufflation of the peritoneal cavity. The oropharyngeal leak pressures were also noted. Statistical analysis was done using SPSS software version 17.0. P <0.05 was considered statistically significant. RESULTS: No significant difference was observed in the heart rate or mean arterial pressure. There was a significant increase in the PECO2 and peak airway pressure after creation of carboperitoneum. There was significant increase in minute ventilation in both groups after creation of carboperitoneum. CONCLUSION: To conclude, I-gel is comparable to endotracheal intubation in terms of adequacy of ventilation. The increase in peak airway pressures is less with I-gel. In addition, postoperative complications are fewer with I-gel.

Single-point versus double-point injection technique of ultrasound-guided supraclavicular block: A randomized controlled study.

BACKGROUND AND AIMS: This study aims to compare the single-point injection and double-point injection technique of ultrasound-guided supraclavicular block with regard to the success rate, time taken to perform the procedure, onset and duration of sensory and motor block, and complications. MATERIAL AND METHODS: A total of 60 American Society of Anesthesiologists physical status I and II patients between 20 and 50 years of age, with body mass index ≤30 kg/m2 posted for forearm surgeries, with anticipated surgical duration more than 1 h were randomly divided into two groups: group S (single-point injection) and group D (double-point injection technique). After locating the brachial plexus with ultrasound, needle was inserted from lateral to medial direction to reach the plexus. In group D, 20 ml of inj. bupivacaine 0.5% was deposited as 10 ml each in superior (in the cluster) and inferior pocket (corner pocket) between the plexus and subclavian artery with the help of hydrodissection while in group S the total 20 ml was deposited in the superior (in the cluster) pocket. The onset of sensory and motor block was assessed using pin prick method and modified Bromage scale. Adequacy of block was ensured by assessing the ulnar, radial, and median nerve distribution. Procedural time was defined from the point of scanning the plexus till the drug was injected completely. Total sensory, motor duration, and complications if any were noted. RESULTS: Group D had higher success rate compared to group S (96.7 vs. 83.3%; P < 0.0001). The total procedural time was significantly more in group D compared to group S (14.6 ± 2.7 vs. 10.1 ± 1.7 min; P < 0.0001). The onset of sensory and motor block was faster and the duration of sensory and motor block was significantly longer in group D. CONCLUSION: The adequacy of block, sensory, and motor duration was significantly high in newer double-point injection technique. However, it requires longer procedural time compared to single-point injection technique.

Intraoperative endobronchial rupture of pulmonary hydatid cyst: An airway catastrophe.

Hydatid cyst disease of lungs may not be symptomatic. It may present as spontaneous rupture in pleura or a bronchus. During spontaneous breathing, cyst content of endobronchially ruptured pulmonary hydatid cyst is mostly evacuated by coughing. However, during positive pressure ventilation such extruded fragments may lodge into smaller airway leading to an airway catastrophe. We present such accidental endobronchial rupture of pulmonary hydatid cyst during surgery, its prompt detection, and management by rigid bronchoscopy.

Anesthetic management of a patient with Montgomery t-tube in-situ for direct laryngoscopy.

The Montgomery silicone t-tube used for post-procedural tracheal stenosis has advantage of acting as both stent and tracheostomy tube. The anesthetic management of patient with t-tube in situ poses a challenge. Safe management of such patients requires careful planning. We describe anesthetic management for direct laryngoscopy of a patient with t-tube in situ.

I-Gel as an intubation conduit: Comparison of three different types of endotracheal tubes.

BACKGROUND AND AIMS: I-Gel®, a novel SAD has been introduced as a ventilating device but has widely gained popularity as conduit for intubation. Unlike intubating laryngeal mask airway (ILMA), I-Gel® does not have an endotracheal tube specially designed for it. Hence the aim of this study was to compare the rate of successful intubation via I-Gel® using three different types of endotracheal tubes. METHODS: We randomised 75 American Society of Anesthesiologists (ASA) physical status I and II patients, between the age group 18-60 years of either sex undergoing elective surgery under general anaesthesia into three groups on the basis of endotracheal tube (ETT), used for intubation via I-Gel®: Group P (Polyvinyl chloride ETT), Group I (Intubating laryngeal mask airway ETT), Group F (flexometallic ETT). After following the standard induction protocol, appropriate size I Gel® was inserted in all patients. Thereafter group specific ETT was inserted via I-Gel®. We recorded and compared the time taken for successful intubation, the success rate, number of attempts taken, manoeuvres used, and complications among three different types of ETT. Quantitative variables were compared using Kruskal Wallis test and the qualitative variables were compared using Chi-square test. RESULTS: The time taken for successful intubation was least in group P (10.51 ± 3.82 seconds). Group P also had the highest first attempt (68%) and overall rate of successful intubation (88%). CONCLUSION: PVC ETT had highest first attempt success rate and required minimum time for endotracheal intubation via I-Gel® when compared to ILMA ETT and Flexible ETT.

Entropy vs standard clinical monitoring using total intravenous anesthesia during transvaginal oocyte retrieval in patients for in vitro fertilization.

STUDY OBJECTIVE: Day care surgery is an important arena for monitors of anesthetic depth where minimizing drug use is essential for rapid turnover. Underdosage, on the other hand, carries the risks of intraoperative awareness and pain. Transvaginal oocyte retrieval (TVOR), often performed under total intravenous anesthesia using propofol and fentanyl in Indian patients, is a procedure of special interest because, in addition to the above concerns, toxic effects of propofol on oocytes have been described. We have studied the role of entropy monitor, a depth of anesthesia monitor, in optomising drug titration and facilitating distinction between analgesic and hypnotic components of anesthesia. DESIGN: Prospective randomized controlled study. SETTING: Operating theater and postoperative recovery area. PATIENTS: One hundred twenty American Society of Anesthesiologists class I and II female patients coming to the IVF centre for TVOR under total intravenous anesthesia using propofol and fentanyl. They were randomly allocated into 2 groups: Group EM (drugs titrated as per entropy values: state entropy and response entropy) and group CM (drugs titrated as per standard clinical monitoring). INTERVENTION: None. MEASUREMENTS: Total propofol consumption (TP), total fentanyl consumption (TF), on-table recovery time (T1), time to discharge (T2), intraoperative awareness (A). MAIN RESULTS: Patients in group EM demonstrated 6.7% lesser consumption of propofol (P= .01), 10.9% more consumption of fentanyl (P= .007) and 1 minute faster recovery on-table (P= .009) as compared to group CM. In the PACU, only 10% patients of group EM required supplemental analgesia as opposed to 28.3% in CM group (P= .01). Time to discharge was similar in both groups and no intraoperative awareness was noted. CONCLUSION: Entropy monitor is a useful tool allowing distinction between analgesic and hypnotic components of general anesthesia in patients undergoing TVOR and facilitating drug titration accordingly. Its impact on intraoperative awareness needs to be further evaluated.

Management of swine-flu patients in the intensive care unit: Our experience.

BACKGROUND: H1N1 pandemic in 2009-2010 created a state of panic not only in India, but in the whole world. The clinical picture seen with H1N1 is different from the seasonal influenza involving healthy young adults. Critical care management of such patients imposes a challenge for anesthesiologist. MATERIALS AND METHODS: A retrospective analysis of hospitalized positive H1N1 patients was performed from July 2009-June 2010. Those requiring the ventilatory support were included in the study. RESULT: 54 patients were admitted in the swine-flu ward during the study period out of which 19 required ventilatory support. The average day of presentation to the health care facility was 6(th) day causing delay in initiation of antiviral therapy and increased severity of the disease. 65% of the ventilated patients were having associated comorbidities. Mortality was 74% among ventilated patients. CONCLUSION: Positive H1N1 with severe disease profile have a poor outcome. Early identification of high-risk factors and thus early intervention in the form of antiretroviral therapy and respiratory care will help in reducing the overall mortality.

Anesthetic management of superior vena cava syndrome due to anterior mediastinal mass.

Anesthetic management of superior vena cava syndrome carries a possible risk of life-threatening complications such as cardiovascular collapse and complete airway obstruction during anesthesia. Superior vena cava syndrome results from the enlargement of a mediastinal mass and consequent compression of mediastinal structures resulting in impaired blood flow from superior vena cava to the right atrium and venous congestion of face and upper extremity. We report the successful anesthetic management of a 42-year-old man with superior vena cava syndrome posted for cervical lymph node biopsy.

Use of intubating laryngeal mask airway in a morbidly obese patient with chest trauma in an emergency setting.

A morbidly obese male who sustained blunt trauma chest with bilateral pneumothorax was referred to the intensive care unit for management of his condition. Problems encountered in managing the patient were gradually increasing hypoxemia (chest trauma with multiple rib fractures with lung contusions) and difficult mask ventilation and intubation (morbid obesity, heavy jaw, short and thick neck). We performed awake endotracheal intubation using an intubating laryngeal mask airway (ILMA) size 4 and provided mechanical ventilation to the patient. This report suggests that ILMA can be very useful in the management of difficult airway outside the operating room and can help in preventing adverse events in an emergency setting.

Donepezil: A cause of inadequate muscle relaxation and delayed neuromuscular recovery.

A 74-year-old female with diabetes mellitus type II and Alzheimer's disease, taking donepezil for 4 months was operated for right modified radical mastectomy under general anesthesia. During the procedure a higher dose of non-depolarizing muscle relaxant was required than those recommended for her age yet the muscle relaxation was inadequate intra-operatively. Residual neuromuscular blockade persisted postoperatively, due to the cumulative effect of large doses of non-depolarizing muscle relaxant, needing post-operative ventilatory assistance. After ruling out other causes of resistance to non-depolarizing muscle relaxants, we concluded that acetylcholinesterase inhibitor donepezil was primarily responsible for inadequate muscle relaxation and delayed post-operative neuromuscular recovery.

Attitude of resident doctors towards intensive care units' alarm settings.

Intensive care unit (ICU) monitors have alarm options to intimate the staff of critical incidents but these alarms needs to be adjusted in every patient. With this objective in mind, this study was done among resident doctors, with the aim of assessing the existing attitude among resident doctors towards ICU alarm settings. This study was conducted among residents working at ICU of a multispeciality centre, with the help of a printed questionnaire. The study involved 80 residents. All residents were in full agreement on routine use of ECG, pulse oximeter, capnograph and NIBP monitoring. 86% residents realised the necessity of monitoring oxygen concentration, apnoea monitoring and expired minute ventilation monitoring. 87% PGs and 70% SRs routinely checked alarm limits for various parameters. 50% PGs and 46.6% SRs set these alarm limits. The initial response to an alarm among all the residents was to disable the alarm temporarily and try to look for a cause. 92% of PGs and 98% of SRs were aware of alarms priority and colour coding. 55% residents believed that the alarm occurred due to patient disturbance, 15% believed that alarm was due to technical problem with monitor/sensor and 30% thought it was truly related to patient's clinical status. 82% residents set the alarms by themselves, 10% believed that alarms should be adjusted by nurse, 4% believed the technical staff should take responsibility of setting alarm limits and 4% believed that alarm levels should be pre-adjusted by the manufacturer. We conclude that although alarms are an important, indispensable, and lifesaving feature, they can be a nuisance and can compromise quality and safety of care by frequent false positive alarms. We should be familiar of the alarm modes, check and reset the alarm settings at regular interval or after a change in clinical status of the patient.

Awareness among resident doctors with regards to cardiac defibrillators.

BACKGROUND AND AIMS: Electrical defibrillation is the most important therapy for patients in cardiac arrest. The audit was aimed to assess awareness among residents with respect to routine preuse checking of cardiac defibrillators. MATERIALS AND METHODS: The audit was conducted at a multispeciality tertiary care referral and teaching center by means of a printed questionnaire from anaesthesiology residents. A database was prepared and responses were analyzed. RESULTS: Eighty resident doctors participated in the audit. Most (97.8%) of the residents were sure of the presence of a defibrillator in the operation room (OR); 70% of postgraduates (PG)s were aware of the location of the defibrillator in the OR as compared to 83.7% of the senior resident (SRs). Also, 32.1% residents routinely check the availability of a defibrillator. The working condition of the defibrillator was checked by 21.7% of the residents; 25.3% ensured delivery of the set charge. Further, 8.2% of residents ensured availability of both adult and paediatric paddles. About 27.8% of residents ensured the availability of appropriate conducting gel and 53.8% residents were of the opinion that the responsibility of checking the functioning and maintenance of the defibrillators lies with themselves. Some 22% thought that both doctors and technical staff should share the responsibility, while 19.5% opined that it should be the responsibility of the technical staff. CONCLUSION: All medical equipment is to be tested prior to initial use and periodically thereafter. An extensive, recurring training program, and continued attention to the training of clinical personnel is required to ensure that they are proficient in the operation and testing of specific defibrillator models in their work area. We conclude that apart from awareness of the use of the equipment we are using, its preuse testing is must. All resident doctors should be aware of the presence and adequate functioning of the defibrillator in their ORs and this audit reinforces the need for training of all resident doctors.

Reasons for cancellation of cases on the day of surgery-a prospective study.

SUMMARY: Late cancellation of scheduled operations is a major cause of inefficient use of operating-room time and a waste of resources. We studied elective operating theatre bookings in general surgical discipline. On the day of surgery the intended list was noted and a list of cancellations with the reason was noted by the attending anaesthesiologist. 1590 patients were scheduled for elective surgical procedures in 458 operation rooms. 30.3 % patients were cancelled on the day of surgery. Of these, 59.7% were cancelled due to lack of availability of theatre time, 10.8% were cancelled because of medical reasons and 16.2% did not turned up on the day of surgery. In 5.4% patients, surgery was cancelled by surgeons due to a change in the surgical plan, 3.7% were cancelled because of administrative reasons, and 4.2% patients were postponed because of miscellaneous reasons. We believe that many of the on-the-day surgery cancellations of elective surgery were potentially avoidable. We observed that cancellations due to lack of theatre time were not only a scheduling problem but were mainly caused by surgeons underestimating the timeneeded for the operation. The requirement of the instruments necessary for scheduled surgical list should be discussed a day prior to planned OR list and arranged. The non-availability of the surgeon should be informed in time so that another case is substituted in that slot. All patients who have met PACU discharge criteria must be discharged promptly to prevent delay in shifting out of the operated patient. Day care patients should be counseled adequately to report on time. Computerized scheduling should be utilized to create a realistic elective schedule. Audit should be carried out at regular intervals to find out the effective functioning of the operation theatre.

Anaesthesia for in vitro fertilisation.

SUMMARY: In vitro fertilization is an upcoming speciality. Anaesthesia during assisted reproductive technique is generally required during oocyte retrieval, which forms one of the fundamental steps during the entire procedure. Till date variety of techniques like conscious sedation, general anaesthesia and regional anaesthesia has been tried with none being superior to the other. However irrespective of the technique the key point of anaesthesia for in vitro fertilization is to provide the anaesthetic exposure for least duration so as to avoid its detrimental effects on the embryo cleavage and fertilization.