Prevalence of Diastolic Dysfunction in Critically Ill Patients Admitted to Intensive Care Unit from a Tertiary Care Hospital: A Prospective Observational Study.

Aim: Critically ill individuals may have left ventricular diastolic dysfunction (LVDD) which can prolong their intensive care unit (ICU) stay. The purpose of this study was to determine the prevalence of LVDD in critically ill adult patients requiring mechanical ventilation in ICU, the effect of LVDD on 28-day survival, and weaning from mechanical ventilation. Methodology: A total of 227 adults who had been on mechanical ventilation for more than 48 hours in an ICU were recruited for this study. The study's parameters were recorded on the third day of mechanical ventilation using a low-frequency phased array probe. A simplified definition of LVDD in critically ill adults was utilized to determine the presence or absence of LVDD. Weaning failure and 28-day mortality were noted. Results: The prevalence of LVDD in adults requiring mechanical ventilation in the ICU was found to be 35.4% (n = 79). Patients with LVDD had the odds of having a 28-day mortality increase by 7.48 (95% CI: 3.24-17.26, p < 0.0001). Patients with LVDD had the odds of having weaning failure increase by 5.37 (95% CI: 2.17-13.26, p = 0.0003). Conclusion: Measures should be taken to detect critically ill adults with LVDD with systolic dysfunction or heart failure with preserved ejection fraction early so that their fluid balance, myocardial contractility, and afterload can be optimized to minimize their morbidity and mortality. Highlights: Critically ill adults with LVDD may have adverse outcomes. Hence, protocol should be in place for diagnosing LVDD early in critically ill adults thereby, measures can be taken to minimize morbidity in those patients. How to cite this article: Luitel B, Senthilnathan M, Cherian A, Suganya S, Adole PS. Prevalence of Diastolic Dysfunction in Critically Ill Patients Admitted to Intensive Care Unit from a Tertiary Care Hospital: A Prospective Observational Study. Indian J Crit Care Med 2024;28(9):832-836.

The Indian Society of Critical Care Medicine Position Statement on the Management of Sepsis in Resource-limited Settings.

Sepsis poses a significant global health challenge in low- and middle-income countries (LMICs). Several aspects of sepsis management recommended in international guidelines are often difficult or impossible to implement in resource-limited settings (RLS) due to issues related to cost, infrastructure, or lack of trained healthcare workers. The Indian Society of Critical Care Medicine (ISCCM) drafted a position statement for the management of sepsis in RLS focusing on India, facilitated by a task force of 18 intensivists using a Delphi process, to achieve consensus on various aspects of sepsis management which are challenging to implement in RLS. The process involved a comprehensive literature review, controlled feedback, and four iterative surveys conducted between 21 August 2023 and 21 September 2023. The domains addressed in the Delphi process included the need for a position statement, challenges in sepsis management, considerations for diagnosis, patient management while awaiting an intensive care unit (ICU) bed, and treatment of sepsis and septic shock in RLS. Consensus was achieved when 70% or more of the task force members voted either for or against statements using a Likert scale or a multiple-choice question (MCQ). The Delphi process with 100% participation of Task Force members in all rounds, generated consensus in 32 statements (91%) from which 20 clinical practice statements were drafted for the management of sepsis in RLS. The clinical practice statements will complement the existing international guidelines for the management of sepsis and provide valuable insights into tailoring sepsis interventions in the context of RLS, contributing to the global discourse on sepsis management. Future international guidelines should address the management of sepsis in RLS. How to cite this article: Juneja D, Nasa P, Chanchalani G, Cherian A, Jagiasi BG, Javeri Y, et al. The Indian Society of Critical Care Medicine Position Statement on the Management of Sepsis in Resource-limited Settings. Indian J Crit Care Med 2024;28(S2):S4-S19.

Hypothalamic-Pituitary Adrenal Axis Status 3 Months After Recovery From COVID-19 Infection.

CONTEXT: Coronavirus disease 2019 (COVID-19) predominantly involves the lungs, albeit many other organ systems, including the hypothalamic-pituitary-adrenal (HPA) axis, can be affected due to the expression of the angiotensin-converting enzyme 2 (ACE2) binding receptor. Few studies have reported the involvement of adrenal gland and the HPA axis during the acute phase of COVID-19; however, the data on the long-term effect of COVID-19 on the HPA axis after acute infection is scarce. OBJECTIVE: To assess and compare the changes in HPA axis in mild, moderate and severe COVID-19 categories at ≥ 3 months after acute infection. METHODS: A prospective, observational study was conducted to assess the HPA axis status among COVID-19 subjects at least 3 months after recovery from acute infection. The study was conducted from June 2021 to May 2022. Subjects visited the hospital in the fasting state (8.00-9.00am), serum cortisol levels were measured at baseline, 30 and 60 minutes after a 1-µg short Synacthen test (SST). RESULTS: A total of 66 subjects ≥ 18 years of age were included in the study. The mean age (SD) was 49.13 ± 11.9 years, 45(68.18%) were male and 21 (31.81%) were female subjects. The mean BMI in the study was 25.91 ± 4.26 kg/m2. Seventeen (25.8%) subjects had mild, twelve (18.2%) had moderate and thirty-seven (56.1%) subjects had severe COVID-19 infection. Out of the sixty-six subjects with COVID-19, nine subjects (9/66, 13.63%) had peak serum cortisol < 496.62 nmol/L suggestive of adrenal insufficiency (AI). SST peak serum cortisol levels did not differ significantly across the disease severity [Mild, (628.50 ± 214.65 nmol/L) vs moderate, [603.39 ± 161.95 nmol/L) vs severe, (597.59 ± 163.05 nmol/L), P = 0.617]. Six subjects with AI came for follow-up at 12 months, and all had normal HPA axis. CONCLUSION: HPA axis is affected in 13.63% (9/66) of subjects at least 3 months after recovery from COVID-19 infection. AI in COVID-19 might be transient and would recover spontaneously. These findings have important implications for the clinical care and long-term follow-up of subjects after COVID-19 infection.

The agreement between arterial and venous lactate in patients with sepsis.

BACKGROUND: Arterial sampling, which is the gold standard for measuring lactate levels in sepsis, is more painful, requires experience and is associated with a higher incidence of morbidity, when compared with venous sampling. This study attempted to measure the correlation and agreement between arterial and peripheral venous (PV) lactate and between arterial and central venous (CV) lactate, with the objective to test interchangeability of the two and possibly support the use of venous lactate levels in resuscitating patients with sepsis. METHODS: Eighty-seven patients admitted to the critical care unit of our hospital with the diagnosis of sepsis or septic shock were included in the study after taking informed consent. The arterial, PV and CV samples were taken within the first 24 hours following admission and within 10 minutes of each other. Lactate levels, CV oxygen saturation (ScvO2 ) and base excess of each sample type were reported within 15 minutes of collection. Patients were followed up for a period of 28 days to record the need for organ support (newly diagnosed renal failure, need for renal replacement therapy [RRT], liver failure, coagulopathy and need for ventilation) and mortality. RESULTS: Pearson correlation for arterial versus PV lactate was 0.76 and for arterial versus CV lactate was 0.992. The mean difference between arterial and PV lactate was found to be -0.30 (95% confidence interval [CI], -0.38 to -0.21). The upper and lower limits of agreement were 0.51 and -1.10, respectively. Mean difference between arterial and CV lactate was found to be -0.13 (95% CI, -0.21 to -0.05). Upper and lower limits of agreement were 0.63 and -0.89, respectively. CONCLUSION: Our study demonstrates a high level of agreement in the lactate levels as measured on venous samples and arterial samples. Venous lactate levels are reliable in resuscitation of patients with sepsis.

Impact of care bundle audit on compliance to device care bundles and device associated infections in the Critical Care Unit of a tertiary care hospital, Southern India - A before-after interventional study.

BACKGROUND: A care bundle comprises a set of evidence-based practices in patient care that are grouped together with the assumption that these practices when performed together will result in better clinical outcomes than when these practices are performed separately. Care bundles for devices when implemented effectively can bring about a reduction in device associated infection rates. METHODS: The study was conducted in three phases, 1 month pre-interventional and interventional phases and 11 months of post-interventional phase in a critical care unit. Compliance to care bundles were recorded by direct observation during daily audit rounds. An educational intervention addressing the healthcare workers regarding bundle care approach was conducted and supplemented with bedside "audit and feedback" during the interventional phase. Audit was conducted in the post-interventional period to study the trend of device associated infections and compliance rates. RESULTS: An increasing trend of month-wise compliance rates to the device care bundles were observed. The month-wise Ventilator Associated Events rates showed a decreasing trend. In the post-interventional phase, the average Catheter-associated Urinary Tract Infection, Central Line Associated Bloodstream Infection and Ventilator Associated Events rates showed a reduction from their respective baseline rates for the study setting. CONCLUSIONS: An educational intervention targeted at the healthcare workers along with daily audit of care bundle practices in the critical care setting led to an increase in the compliance to device care bundles and a reduction in the incidence of Catheter-associated Urinary Tract Infection, Central Line Associated Bloodstream Infection and Ventilator Associated Events rates in the critical care setting.

Angiotensin ii therapy in refractory septic shock: which patient can benefit most? A narrative review.

Patients with septic shock who experience refractory hypotension despite adequate fluid resuscitation and high-dose noradrenaline have high mortality rates. To improve outcomes, evidence-based guidelines recommend starting a second vasopressor, such as vasopressin, if noradrenaline doses exceed 0.5 µg/kg/min. Recently, promising results have been observed in treating refractory hypotension with angiotensin II, which has been shown to increase mean arterial pressure and has been associated with improved outcomes. This narrative review aims to provide an overview of the pathophysiology of the renin-angiotensin system and the role of endogenous angiotensin II in vasodilatory shock with a focus on how angiotensin II treatment impacts clinical outcomes and on identifying the population that may benefit most from its use.

Effectiveness of Swallowing and Oral Care Interventions on Oral Intake and Salivary Flow of Patients Following Endotracheal Extubation at a Tertiary Care Center: A Randomized Controlled Trial.

Introduction: Endotracheal intubation and mechanical ventilation are the most frequently used life-sustaining interventions in critical care. Prolonged intubation can lead to post-extubation dysphagia, affecting the individual's nutritional level and communication ability. Thereupon, this study aims to assess the effectiveness of swallowing and oral care interventions in resuming oral intake and increasing salivary flow in post-extubation patients. Methods: A randomized controlled trial was conducted in critical care units of a tertiary care setting, where 92 post-extubation patients who had undergone intubation for≥48 hours were enrolled. The intervention group received swallowing and oral interventions, including safe swallowing education (SSE), toothbrushing, salivary gland massage, oral cavity, and swallowing exercises. In contrast, the control group received standard oral care every 8th hour. Oral intake was assessed daily with the Functional Oral Intake Scale, and the salivary flow measurement was assessed with oral Schirmer's test on the 1st, 3rd, and 7th day after extubation. Results: The baseline demographic and clinical characteristics showed that the groups were homogenous. The intervention group achieved total oral intake two days earlier than the control group. Findings also showed that the participants in the intervention group had a significant increase in salivary flow than in the control group on the 3rd and 7th days of the intervention. Conclusion: Swallowing and oral care interventions help post-extubation patients resume early oral intake and increase salivary flow after prolonged intubation. Hence, it improves the patient's outcome toward a healthy life.

Development and Validation of an Acute Respiratory Distress Syndrome Prediction Model in Coronavirus Disease 2019: Updated Lung Injury Prediction Score.

OBJECTIVE: To develop and validate an updated lung injury prediction score for coronavirus disease 2019 (COVID-19) (c-LIPS) tailored for predicting acute respiratory distress syndrome (ARDS) in COVID-19. PATIENTS AND METHODS: This was a registry-based cohort study using the Viral Infection and Respiratory Illness Universal Study. Hospitalized adult patients between January 2020 and January 2022 were screened. Patients who qualified for ARDS within the first day of admission were excluded. Development cohort consisted of patients enrolled from participating Mayo Clinic sites. The validation analyses were performed on remaining patients enrolled from more than 120 hospitals in 15 countries. The original lung injury prediction score (LIPS) was calculated and enhanced using reported COVID-19-specific laboratory risk factors, constituting c-LIPS. The main outcome was ARDS development and secondary outcomes included hospital mortality, invasive mechanical ventilation, and progression in WHO ordinal scale. RESULTS: The derivation cohort consisted of 3710 patients, of whom 1041 (28.1%) developed ARDS. The c-LIPS discriminated COVID-19 patients who developed ARDS with an area under the curve (AUC) of 0.79 compared with original LIPS (AUC, 0.74; P<.001) with good calibration accuracy (Hosmer-Lemeshow P=.50). Despite different characteristics of the two cohorts, the c-LIPS's performance was comparable in the validation cohort of 5426 patients (15.9% ARDS), with an AUC of 0.74; and its discriminatory performance was significantly higher than the LIPS (AUC, 0.68; P<.001). The c-LIPS's performance in predicting the requirement for invasive mechanical ventilation in derivation and validation cohorts had an AUC of 0.74 and 0.72, respectively. CONCLUSION: In this large patient sample c-LIPS was successfully tailored to predict ARDS in COVID-19 patients.

Prone ventilation in a pregnant patient with scrub typhus-induced acute respiratory distress syndrome.

A 23-year-old primigravida at 20 weeks of gestation presented to our hospital with undifferentiated febrile illness and severe acute respiratory distress syndrome. She was intubated in the emergency department and transferred to the intensive care unit. Initial treatment included ventilatory care, vasopressor support and broad-spectrum antibiotics. Based on a positive PCR assay for scrub typhus, she was treated with intravenous doxycycline and azithromycin. Despite reduction in fever, her oxygenation further declined. Following a risk-benefits assessment, we decided to ventilate her in prone position for 8 hours a day for three consecutive days using a checklist-based protocol. Her oxygenation indices and lung compliance markedly improved over this period, and she was extubated a day later. She was eventually discharged home after 1 week.

Procalcitonin Assay Has No Role in the Routine Assessment of Severe Trauma Patients at Admission to the Emergency Department.

Introduction A key challenge in emergency departments (ED) is the early recognition of sepsis or the potential for sepsis in patients. Appropriate and accurate ED triage will ensure improved case management. This study analysed the association between ED findings at admission and outcomes in patients presenting with severe trauma. Methods This was a prospective study conducted at a tertiary level ED and included severely injured adult patients who presented to the ED within 24 hours of injury. Data collected included clinical findings and imaging reports at initial assessment, serum procalcitonin (PCT), length of ICU and hospital stay, the incidence of bloodstream and other infections, and patient outcome as discharge from care or death. Multiple logistic regression was used to assess the association between outcome variables and independent variables. Results A total of 155 patients were included in the study. Head and neck (61.9%), extremity (58%), and chest (45%) were more commonly injured. Injury Severity Score (ISS) >25, Glasgow Coma Scale (GCS) score <8, head and neck injuries, and extremity injuries were found to be significantly associated with mortality. Bloodstream infections were more common in the presence of lung contusions, abdominal injury, operative management, and blood transfusions. PCT levels at admission did not have a significant predictive value for mortality, bloodstream infections, other infectious complications, or length of ICU stay. Conclusions Head injuries were the most common cause of mortality in our study. In addition to the anatomical region involved, ISS and GCS have a significant association with mortality. PCT levels at ED admission do not have any prognostic value and need not be routinely analysed.

Use of a Clinical Audit System in Implementing Surviving Sepsis Campaign Guidelines in Patients With Peritonitis.

Background Sepsis is the predominant cause of morbidity and mortality in patients with peritonitis. "Surviving Sepsis Campaign" (SSC) is an international effort in reducing mortality based on evidence-based guidelines. This study aims to assess the impact of audit-based feedback in a Plan-Do-Study-Act (PDSA) format on improving the implementation of the SSC guidelines in patients with generalized peritonitis at our center. Methods This prospective observational study was conducted in four audit cycles in PDSA format. Multi-departmental inputs were taken to suggest modifications in practice. A questionnaire-based analysis of reasons for non-compliance was performed to find out the opinions and reasons for non-compliance. Morbidity, mortality, and the length of ICU and hospital stay among these patients were also analyzed. Results Baseline compliance with intravenous (IV) bolus administration, central venous pressure (CVP)-guided fluids, and inotropes support when indicated were 100%. Over the course of the three audit cycles, statistically significant improvement in compliance was noted for obtaining blood cultures before antibiotics, antibiotic administration within three hours of presentation, and serum lactate measurement. Overall bundle compliance improved from 9.2% to 64.7% by the end of audit cycle III. Conclusions This study demonstrates that audit-based feedback is a dependable means of improving compliance with SSC guidelines. It brings about improvement by educating users, modifying their behavior through feedback, and enhances process improvement by identifying and correcting systemic deficiencies in the organization.

The effect of hand hygiene audit in COVID intensive care units in a tertiary care hospital in South India.

BACKGROUND: In the era of COVID-19 pandemic, there is an upsurge of healthcare-associated infections (HAI) in COVID intensive care units (ICUs), which can be reduced by following proper hand hygiene (HH) practice. Performing HH auditing in COVID ICU and providing timely feedback to the stake holders is crucial to reduce HAIs. METHODS: From November 2020- April 2021, HH audit was conducted in COVID ICUs. HH complete adherence rate (HHCAR), HH partial adherence rate (HHPAR) and HH total adherence rate (HHTAR) were analyzed. Profession-specific HHTAR and moment-specific HHTAR (for each WHO moment) were also calculated. RESULTS: HHCAR, HHPAR and HHTAR were found as 30.8%, 34.5% and 65.3% respectively. There was a significant increase in the monthly HHTAR from 26.7% to 68.4% (P < .001). The profession-specific HHAR was found to be highest among doctors (67.5%) and nurses (66.4%). As the HHTAR increases there is a significant decrease in device associated infection (DAI) rate from 24.7 to 11.5 per 1,000 device days. CONCLUSIONS: Auditing HH and providing timely feedback significantly improved HH compliance. The need of the hour is to regularly conduct HH audit in COVID locations of all healthcare facilities to reduce HAI rate among the COVID- 19 infected patients in ICUs.

Comparison of total intravenous anesthesia vs. inhalational anesthesia on brain relaxation, intracranial pressure, and hemodynamics in patients with acute subdural hematoma undergoing emergency craniotomy: a randomized control trial.

BACKGROUND: The major goals of anesthesia in patients with severe traumatic brain injury (TBI) are-maintenance of hemodynamic stability, optimal cerebral perfusion pressure, lowering of ICP, and providing a relaxed brain. Although both inhalational and intravenous anesthetics are commonly employed, there is no clear consensus on which technique is better for the anesthetic management of severe TBI. METHODS: Ninety patients, 18-60 years of age, of either gender, with GCS < 8, posted for emergency evacuation of acute subdural hematoma were enrolled in this prospective trial, and they were randomized into two groups of 45 each. Patients in group P received propofol infusion at 100-150 mg/kg/min for maintenance of anesthesia and those in group I received ≤ 1 MAC of isoflurane. Hemodynamic parameters were monitored in all patients. ICP was measured at the dural opening and brain relaxation was assessed by the operating surgeon on a four-point scale (1-perfectly relaxed, 2-satisfactorily relaxed, 3-firm brain, and 4-bulging brain) at the dural opening. It was reassessed at dural closure. RESULTS: Brain relaxation, both at dural opening and closure, was significantly better in patients who received propofol compared to those who received isoflurane. ICP was significantly lower (25.47 ± 3.72 mmHg vs. 23.41 ± 3.97 mmHg) in the TIVA group. Hemodynamic parameters were well maintained in both groups. CONCLUSIONS: In patients with severe TBI, total intravenous (Propofol)-based anesthesia provided better brain relaxation, maintained a lower ICP along with better hemodynamics when compared to inhalational anesthesia. CLINICAL TRIAL REGISTRATION: Clinical trials registry (NCT03146104).

The impact of antimicrobial stewardship programme on regulating the policy adherence and antimicrobial usage in selected intensive care units in a tertiary care center - A prospective interventional study.

Purpose: Antimicrobial resistance (AMR) presents a significant threat to human health. The root cause for this global problem is irrational antimicrobial usage. Antimicrobial stewardship (AMS) emphasises on the appropriate use of antibiotics and ensures strict implementation of antimicrobial policy guidelines. This study was conducted to evaluate the impact of auditing of AMS programme on regulating the antimicrobial policy adherence and antimicrobial usage in hospital intensive care units. Materials and Methods: This was a prospective interventional study. It consisted of pre-implementation and implementation phases 6 months each. Two hundred and eighty patients were enrolled. Details of antibiotic consumption, surgical prophylaxis, culture/sensitivity patterns, de-escalation rates, etc., were collected in both phases. The implementation phase, in addition, included stewardship audit rounds. Results: In pre-implementation phase and implementation phases: policy adherence rates were 23.7% and 41.8%, respectively, de-escalation rates were 22.73% and 43.48%, respectively. Cultures were sent before the initiation of antimicrobials in 36.73% cases during the pre-implementation phase, which improved to 60.41% during the implementation phase. Defined daily dose (DDD) for the antibiotics was 98.66 DDD 100BD during the pre-implementation phase, which reduced to 91.62 DDD 100BD in the implementation phase. Total days of therapy (DOT) in the pre-implementation phase were 561 DOT1000BD, which reduced to 463 DOT1000BD during the implementation phase. Conclusions: Implementation of continuous monitoring of the AMS programme, therefore, has a definite role in reducing the antimicrobial consumption and improving the compliance to the policy guidelines. A more robust study for a prolonged period is, however, necessary to have a better analysis of the outcome.

Correlation between correctly sized uncuffed endotracheal tube and ultrasonographically determined subglottic diameter in paediatric population.

BACKGROUND AND AIMS: Conventional age-based formulae often fail to predict correct size of endotracheal tube (ETT). In this study, we evaluated usefulness of ultrasound in determining appropriate tube size and derived a formula which enables us to predict correct tube size. METHODS: A total of 41 American Society of Anesthesiologists' physical status 1 and 2 children in the age group of 2-6 years, undergoing elective surgery under general anaesthesia with uncuffed ETT were included in the study. Ultrasonography (US) was used to measure the subglottic diameter after induction of anaesthesia. The trachea was intubated with an ETT that allowed an audible leak between 15-30 mmHg. Pearson's correlation was used to assess the correlation between US measured subglottic diameter (US-SD) with diameter of ETT used. Linear regression was used to derive a formula for predicting ETT size. RESULTS: We found that US-SD and patient's age correlated well with actual ETT OD (r: 0.83 and 0.84, respectively). Age-based formula, ETT ID = (Age/3) +3.5 [r: 0.81] had better correlation with actual ETT OD than conventional age-based Cole's formula, i.e., ETT ID = Age/4 + 4 [r: 0.77]. Our results enabled us to derive a formula for selecting uncuffed ETT based on US-SD. CONCLUSION: Our study concludes that although US-SD correlates with actual tracheal tube used and may be useful in choosing appropriate size ETT, there was no difference in number of correct predictions of ETT size by US measurement, universal formula, and locally derived formula.

Perineural vs. intravenous dexmedetomidine as an adjunct to bupivacaine in ultrasound guided fascia iliaca compartment block for femur surgeries: A randomised control trial.

BACKGROUND AND AIMS: Perineural and intravenous dexmedetomidine as a local anaesthetic adjunct has not been compared previously in fascia iliaca compartment block (FICB). The aim of this study was to compare the efficacy and side effect profile of dexmedetomidine as an adjunct to bupivacaine in single dose FICB for femur surgeries in two different routes i.e., perineural and intravenous route. METHODS: Eighty American Society of Anesthesiologists physical status 1, 2 or 3 patients posted for femur surgeries were randomised to receive ultrasound guided FICB. Intravenous group(ID) received 40 mL of 0.25% bupivacaine with 2 mL of 0.9% saline for FICB along with 1 µg/kg dexmedetomidine intravenous infusion over 30 min as loading dose followed by 0.5 µg/kg/h as maintenance dose till the end of surgery. Perineural group (LD) received 40 mL of 0.25% bupivacaine with 2 mL of 1 µg/kg dexmedetomidine for FICB. M ean duration of postoperative analgesia and 24 h postoperative morphine consumption as primary and secondary outcome respectively, has been compared. RESULTS: The duration of postoperative analgesia was 8 h 36 min ± 1 h 36 min and 10 h 42 min ± 1 h 36 min for the ID and LD groups, respectively (P = 0.001). A 24 h postoperative morphine consumption in Group ID was 19.7 ± 1.9 mg compared to 17.5 ± 2.2 mg in LD groups (P = 0.001). CONCLUSION: Perineural dexmedetomidine effectively prolongs the USG guided FICB analgesic duration and reduces the 24 h postoperative morphine consumption when compared to intravenous dexmedetomidine as a local anaesthetic adjuvant for femur surgeries.

Changes in Gas Composition during Low Flow Anaesthesia without Nitrous Oxide.

INTRODUCTION: Low flow anaesthesia utilising Oxygen (O2) and Nitrous Oxide (N2O) mixture carries a risk of hypoxia, but avoiding N2O results in increased analgesic and volatile anaesthetic agent requirement. AIM: This study attempted to find the lowest Fraction of inspired Oxygen (FiO2) levels achieved with a mixture of 300 mL/min each of O2 and medical air over two hours and to compare the overall analgesic requirement and cost while using similar flows of N2O and O2, respectively. MATERIALS AND METHODS: A prospective observational study was conducted between March 2015 and June 2016 at the Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India. Patients of American Society of Anaesthesiologists (ASA) Grade 1 and 2 undergoing surgery under general anaesthesia with an endotracheal tube were included in the study, in two groups of 40 each. In the initial ten minutes following induction of anaesthesia, both groups received high Fresh Gas Flows (FGF) of 3 L/min each (Group O: medical air and oxygen; Group N: N2O and oxygen), following which the FGF rates were reduced to 300 ml/min each. Any value of FiO2 lesser than 0.3 during the duration of anaesthesia was considered to render the technique unsafe for clinical use. SPSS software version 20.0 was used to generate data and figures. RESULTS: The lowest FiO2 recorded was 0.33 in Group O and 0.3 in Group N which occurred at the end of two hours. Mean analgesic requirement was significantly higher in Group O compared to Group N (151.85 µg, 124.85 µg; p-value=0.004) with a 62% increase in the cost incurred. CONCLUSION: The use of medical air and oxygen in flows of 300 ml/min each following initial high flows of 3 L/min appears to be a safe technique. However, this combination was associated with an increase in the cost of anaesthesia and in the need for additional intra-operative analgesia.