Clinical trials

The goal of this observational study is to evaluate thyromental distance (TMD) and mandibular triangle perpendicular length (MTPL); to know which correlates better with the incisor vallecula distance (IVD). Based on the direction and strength of the correlation measure, a multiple regression equation can then be created to first predict the IVD with external linear measure, and second, based on IVD length prediction, the appropriate laryngoscope blade size can be ascertained.

Direct laryngoscopy and intubation is an essential initial aspect of airway access during general anesthesia. To perform the procedure effectively, it requires adequate mouth opening, head and neck movement, and a normal temporo-mandibular joint mobility. Any issue with the above three results in a compromised upper airway at the outset and the condition is known as anticipated difficult airway, i.e. an airway that is difficult to access with conventional laryngoscopy and intubation methods. To overcome the difficulty, either one has to resort to newer advanced technique and equipment or the available conventional technique needs to be refined and modified to suit the requirement. While the former requires extraordinary expertise and finances, an option difficult to achieve in developing countries; the latter warrants focused interest to develop alternative approach with the same set of equipments. Since submucous fibrosis and the associated restricted mouth opening have taken the proposition of an epidemic owing to widespread use of betel nut and tobacco; these patients, when requiring surgery, are difficult candidates for GA and airway control. The fact that, when they arrive as pre-surgical candidates, they have variable degree of mouth opening restriction, which if approached with a strategy, may be amenable to conventional control of airway. If investigators paint all the patients with mouth restriction as difficult airway, it will result in uncalled surgical, economic, health system and psychological burden. Therefore, it is prudent to undertake research relating to refinement of airway access techniques with the easily available, cheap and user- friendly equipment (conventional laryngoscope), such that a proportion of above stated burden can be reduced. In view of the above, investigators plan to undertake a study to enhance our working knowledge with a conventional laryngoscope (Macintosh) to facilitate ways to control the airway difficulty secondary to mouth opening restriction. Investigators believe that the prospective knowledge thus generated would help us identify whether there is a feasibility of conventional airway management or an alternative advanced access technique is needed in the first place. This will prevent undue cancellations, delayed surgeries, and patient morbidity.

Total intravenous anaesthesia (TIVA) is now a preferred technique for providing general anaesthesia (GA) because of its various inherent advantages like reduced postoperative nausea and vomiting (PONV), improved quality of post-operative recovery, anti-inflammatory and antioxidant action, anti-neoplastic activity, analgesic action, and absence of greenhouse effect. The evolution and advancement in automated anaesthesia delivery systems particularly for propofol have made propofol-TIVA more efficient by removing the human interface for both rate and concentration adjustments. Automated computer-controlled closed loop anaesthesia device adjusts propofol delivery based on patient's frontal cortex electrical activity determined by bispectral index (BIS). Closed loop anaesthesia delivery system (CLADS) is an indigenously developed patented (Patent no.502/DEL/2003 \& US 9,108,013 B2) computer-controlled anaesthesia delivery system which works with feedback loop information elicited by BIS monitoring and delivers propofol TIVA to the patient via a non-TCI automated infusion pump. It has been an extensively used and validated in patients undergoing both cardiac and non-cardiac surgical procedures. A new compact and upgraded version of CLADS is now available. This new version incorporates the anesthetic depth monitor, hemodynamic monitor, controller, user interface and actuator syringe pump into a single, compact and user-friendly module. The investigators aim to conduct a prospective randomized pilot study comparing the new CLADS and older CLADS version with respect to: adequacy of anaesthesia depth maintenance, performance characteristic of propofol delivery system, propofol requirement, haemodynamics stability, recovery from anesthesia and postoperative sedation.

The pharmacokinetic profile of various drugs is altered in obese patients especially those administered by the intravenous route. Propofol is the commonly used intravenous anesthetic agent for induction and maintenance of anaesthesia as part of total intravenous anaesthesia (TIVA) regimen. A major concern with propofol dosing based on total body weight (TBW) in obese patients is disproportionate drug administration leading to undue drug accumulation in body with a potential to overdosing, delayed recovery from anaesthesia, and adverse hemodynamic outcome. Studies on propofol dosing based on various weight scalars have recommended that lean body weight (LBW) should be used for calculating bolus dose during anaesthesia induction and TBW or adjusted body weight (ABW) for arriving at an infusion dose required for maintenance of anesthesia. Although propofol delivery based on dose calculated by TBW has been well researched the evidence for propofol delivery based on dose calculated by ABW is lacking. Recent advance in the delivery of propofol has been the development of computer controlled anaesthesia delivery systems. These devices deliver propofol based on patient's frontal cortex electrical activity as determined by bispectral index (BIS). Evaluation of anaesthesia delivery by these systems has shown that they deliver propofol and maintain depth of anaesthesia with far more precision as compared to manual administration. One such indigenously developed computer controlled anaesthesia delivery system is the closed loop anesthesia delivery system (CLADS). CLADS functions on control of processed EEG response parameter captured from anesthetized patients with the help of a BIS- monitor, which is continuously fed into an automated drug infusion pump. The infusion pump then accordingly delivers the anesthetic drug to the patients based on pharmacodynamic requirements. The investigators plan to evaluate the propofol maintenance dose requirement based on TBW versus ABW using CLADS for propofol delivery.

Postoperative delirium (POD) is the most common adverse neurologic complication that can occur in patients of any age. Its incidence varies across age groups and is substantially influenced by patient-related risk factors. POD occurs in 17%-61% of major surgical procedures. Several risk factors which contribute to the development of POD include age more than 60 years, pre-existing cognitive dysfunction, presence of comorbidities, sensorial deficits, malnutrition, polypharmacy, impaired physical mobility and frailty. Postoperative delirium has several wide ranging and adverse outcomes that are consistently associated with delirium such as mortality, increased length of hospital stay, and increased hospital costs. A recently devised tool for rapid assessment of delirium is the 4 A's test. It has now been validated for identifying delirium in the surgical population. The proposed prospective observational study will be conducted on 150 patients belonging to ASA Physical Status I-III of either sex, scheduled to undergo non-cardiac surgery under general anaesthesia (GA), requiring at least 24 hours of postoperative inpatient care. This prospective, observational study aims to evaluate the incidence, risk factors and outcomes of postoperative delirium in elderly patients more than 65 years of age undergoing non-cardiac surgery.

Endotracheal tube (ETT) is the gold standard conduit for providing controlled ventilation during general anaesthesia (GA). however, the supra-glottic airway (SGA) devices in particular the laryngeal mask airway (LMA) and its variants have become a reliable alternative to ETT for carrying out controlled ventilation. Of the several variants of LMA available today, the proseal LMA (PLMA) is preferred for controlled ventilation. The various advantages of LMA includes, a lower incidence of postoperative sore throat and superior haemodynamic profile during surgery. However, one aspect of providing anaesthesia with LMA compared to ETT is the ability of LMA to maintain equivalent depth of anaesthesia with lower anaesthetic requirement, is quiet intriguing and evidence to this regard is very limited. By measuring the anaesthesia requirement using a robust computerised delivery system such as the closed loop anaesthesia delivery system (CLADS) we can establish for sure the anaesthesia required for maintaining intraoperative mechanical ventilation with the use of these two (ETT and PLMA) airway management devices. This randomised controlled study aims to calculate the anaesthesia requirement as determined by the total amount of propofol consumed for maintaining anaesthesia with ETT versus PLMA

In Anaesthesia Practice, an Informed consent involves discussing the risks and benefits involved with a certain procedure and its alternatives. Though it is intended to promote patient autonomy and enhance decision-making, the risk profiling, detailing and discussing; generally walks one-way, from the anaesthesiologist to patient/party. This monologue-leaned communication is neither free flowing nor the patients are allowed to 'speak-up-first' on their concerns or queries. Several gaps can be identified including reluctance on the part of the anaesthesiologist to engage the patients in decision making or not upholding the patient preferences; or patient lacking sufficient knowledge to make an informed choice. Therefore, for risk communication, the very context has to be tailored to patient's individual needs. There is no available study till date which has tried to address as how the communication between patient and the anaesthesiologist is influenced by the 'gender' of the patient concerned. This situates a need to understand how the 'gender' of a patient can influence communication during an Informed consent conversation on anaesthesia risk(s). The study will explore to decipher if difference(s) in patient's gender influence their perceptions and understanding of anesthesia-related risks, and if the difference will influence the future lines of communication involving either of the gender. This prospective study will be based on conversation model based interview designed to assess the nuances of gender- based differences in risk perception and information exchange during pre-anaesthetic consultations.