Many molecules can exist as right-handed and left-handed forms that are non-superimposable mirror images of each other. They are known as enantiomers or substances of opposite shape. Such compounds are also said to be chiral (Greek chiros meaning 'hand'). Such chiral molecules are of great relevance to anaesthetic theory and practice. This review summarizes the basic concepts, pharmacokinetic and pharmacodynamic aspects of chirality, and some specific examples of their application in anaesthesia, along with recent advances to elucidate the anaesthetic mechanisms. Chirality is relevant to anaesthesia, simply because more than half of the synthetic agents used in anaesthesia practice are chiral drugs. Almost all these synthetic chiral drugs are administered as racemic mixture, rather than as single pure enantiomers. These mixtures are not drug formulations containing two or more therapeutic substances, but combination of isomeric substances, with the therapeutic activity residing mainly in one of the enantiomer. The other enantiomer can have undesirable properties, have different therapeutic activities or be pharmacologically inert. Specific examples of application of chirality in anaesthetic drugs include inhalational general anaesthetics (e.g. isoflurane), intravenous anaesthetics (e.g. etomidate, thiopentone), neuromuscular blocking agents (e.g. cisatracurium), local anaesthetics (e.g. ropivacaine and levobupivacaine) and other agents (e.g. levosimendan, dexmedetomidine, L-cysteine). In the recent advances, chirality study has not only helped new drug development as mentioned above, but has also contributed in a more profound way to the understanding of the mechanism of anaesthesia and anaesthetic drugs.

Background: Bispectral index monitoring system (BIS) is one of the several systems used to measure the effects of anaesthetic and sedative drugs on the brain and to track changes in the patient's level of sedation and hypnosis. BIS monitoring provides information clinically relevant to the adjustment of dosages of sedating medication. It can help the nursing personnel in preventing under- and over sedation among intensive care unit (ICU) patients. Objective: The present study was conducted to assess the knowledge of nursing personnel working in the ICU regarding BIS. Methods: Fifty-four subjects participated in the study. A structured questionnaire was developed to assess the knowledge of the nursing personnel regarding BIS. Focus group discussions were held among the nursing personnel to know their views regarding BIS. Results: Mean age (years) of the subjects was 30.7΁7.19 (21-47) years, with a female preponderance. Although the use of BIS in ICU is not common, majority (94.44%) were aware of BIS and its purpose. 79.62% of the subjects knew about its implication in patient care. The mean knowledge score of the subjects was 11.87΁2.43 (maximum score being 15). Conclusion: There exists an awareness among the critical care nursing staff in our institution regarding BIS and its clinical implications. Its use in the critical care setting may benefit the patients in terms of providing optimal sedation.

Introduction: Although most general anaesthesia procedures are performed without any complications, volatile agents may have adverse effects on various living systems. This study aims to compare the antioxidant effects of isoflurane and N-acetylcysteine (NAC) on liver function. Methods: Forty-one patients in the ASA I-II risk groups, who were scheduled to undergo gynaecologic laparoscopy, were randomly divided into two groups: The placebo (group P, n=21) and the NAC group (group N, n=20). In both groups, anaesthesia was maintained with 1-2% isoflurane in 50% Oxygen-50% N ₂ O at 6 l/min, also administered by inhalation. Venous blood samples were obtained before anaesthesia induction, and then in the postoperative 1 ^st hour and at the 24 ^th hour. The samples were centrifuged and serum levels of glutathione S-transferase (GST), malondialdehyde (MDA), aspartate amino transferase (AST), alanine amino transferase (ALT), lactate dehydrogenase (LDH), gamma glutamyltranspeptidase (GGT), prothrombin time (PT), activated partial thromboplastin time (aPTT) and international normalised ratio were determined. Results: GST levels were significantly higher in group N than in group P in the postoperative 1 ^st hour. Postoperative values of GST in the two groups were higher when compared to preoperative values (P<0.05). When postoperative levels were compared with preoperative levels, the postoperative MDA levels of group N were significantly higher (P<0.05). Levels of AST, ALT, GGT and LDH in both groups revealed significant decreases at the postoperative 1 ^st hour and postoperative 24 ^th hour compared to preoperative values (P<0.05, P<0.001). PT values were significantly higher in both groups in the postoperative 1 ^st hour and 24 ^th hour (P<0.05, P<0.001), although there were no differences in aPTT levels. Conclusion: Our results showed that liver functions were well preserved with administration of NAC during anaesthesia with isoflurane. Isoflurane with NAC has lesser effect on liver function tests compared to isoflurane alone.

Background: Use of suxamethonium is associated with an increase in intraocular pressure (IOP) and may be harmful for patients with penetrating eye injuries. The purpose of our study was to observe the efficacy of dexmedetomidine for prevention of rise in IOP associated with the administration of suxamethonium and endotracheal intubation. Methods: Sixty-six American Society of Anaesthesiologists I or II patients undergoing general anaesthesia for non-ophthalmic surgery were included in this randomized, prospective, clinical study. Patients were allocated into three groups to receive 0.4 mg/kg dexmedetomidine (group D4), 0.6 mg/kg dexmedetomidine (group D6) or normal saline (group C) over a period of 10 min before induction. IOP, heart rate and mean arterial pressure were recorded before and after the premedication, after induction, after suxamethonium injection and after endotracheal intubation. Results: Fall in IOP was observed following administration of dexmedetomidine. IOP increased in all three groups after suxamethonium injection and endotracheal intubation, but it never crossed the baseline value in group D4 as well as in group D6. Fall in mean arterial pressure was noticed after dexmedetomidine infusion, especially in the D6 group. Conclusion: Dexmedetomidine (0.6 mg/kg as well as 0.4 mg/kg body weight) effectively prevents rise of IOP associated with administration of suxamethonium and endotracheal intubation. However, dexmedetomidine 0.6 mg/kg may cause significant hypotension. Thus, dexmedetomidine 0.4 mg/kg may be preferred for prevention of rise in IOP.

Introduction: This randomized double blind study was started with an objective of management of spinal anaesthesia-induced hypotension in elective caesarean section by combining two commonly used vasopressors - ephedrine and phenylephrine in half of their usual doses with an expectation of reducing their foetomaternal side effects. Methods: One hundred and thirty two patients were randomized into three groups to receive either 100 mg/ml phenylephrine (group-P, n=31) or 3 mg/ml ephedrine (group-E, n=33) or 50 mg phenylephrine plus 1.5 mg ephedrine/ml (group-PE, n=29). Immediately after spinal injection the study solution was started prophylactically in every patient at the rate of 40 ml/h. A predefined algorithm was used to adjust the infusion rate according to the systolic blood pressure (SBP). Results: Mean fall of SBP was significantly more in group-E than group-P (P=0.009) and group-PE (P=0.013). This was not significantly different when compared between group-P and group-PE (P=0.9). Episodes of hypotension and tachycardia were more in group-E than the other two groups. Statistically significant tachycardia was seen in Group-E than that in other two groups. Incidence of bradycardia and hypertension did not differ significantly among the groups. Maternal nausea and Apgar score were also comparable in three groups. Conclusion: Current study claims that prophylactic phenylephrine 100 mg/ml is a better choice than ephedrine (3 mg/ml) or 50 mcg phenylephrine plus 1.5 mg ephedrine/ml in prevention of spinal anaesthesia-induced hypotension in elective caesarean section. Combination of two drugs in half the usual dose has no added advantage over phenylephrine, but this is better than ephedrine alone.

Background: Inguinal hernia repair can be performed under satisfactory anaesthetic conditions using general, regional and peripheral nerve block anaesthesia. Unilateral spinal anaesthesia provides optimal anaesthesia, with stable haemodynamics and minimal adverse events. The paravertebral block, being segmental in nature, can be expected to produce some advantages regarding haemodynamic stability and early ambulation and may be a viable alternative. Methods: Fifty-four consenting male patients posted for inguinal hernia repair were randomized into two groups, to receive either the two-segment paravertebral block (group-P, n=26) at T10 and L1 or unilateral spinal anaesthesia (group-S, n=28), respectively. The time to ambulation (primary outcome), time to the first analgesic, total rescue analgesic consumption in the first 24-hour period and adverse events were noted. Results: Block performance time and time to reach surgical anaesthesia were significantly higher in the patients of group-P (P<0.001). Time to ambulation was significantly shorter in group-P compared to group-S (P<0.001), while postoperative sensory block was prolonged in patients of group-S; P<0.001. A significantly higher number of patients could bypass the recovery room in group-P compared to group-S, (45% versus 0%, respectively, P<0.001). No statistically significant difference in adverse outcomes was recorded. Conclusion: Both the paravertebral block and unilateral spinal anaesthesia are effective anaesthetic techniques for uncomplicated inguinal hernia repair. However, the paravertebral block can be an attractive alternative as it provides early ambulation and prolonged postoperative analgesia with minimal adverse events.

Context: Total knee replacement (TKR) is often carried out using a tourniquet to minimize intraoperative blood loss. However, its application enhances local fibrinolysis, resulting in excessive blood loss during the post-operative period. Fibrinolytic profile varies in different regions and races. Tranexamic acid has been shown to reduce post-operative blood loss and the need for transfusion in TKR. However, there is paucity of literature from the Indian population and the efficacy of the agent has not been tested in Indian patients undergoing TKR. Aims: Effect of tranexamic acid on blood loss in TKR surgery in the Indian population. Setting and Design: In this double-blinded study, 40 patients undergoing unilateral TKR were randomly divided into two groups. Methods: All patients were conducted under spinal anaesthesia using injection bupivacaine 0.5% heavy 12-15 mg. The treatment group received 10 mg/kg tranexamic acid, intravenous (IV), half an hour before deflation of the tourniquet, with a second dose of 2 mg/kg administered 3 hours after the first dose. The exact protocol was followed for the placebo group, except that normal saline was used instead of tranexamic acid. Blood loss, blood transfusion details and change in haemoglobin levels were noted. Statistical Analysis: Student's paired 't' test was used in statistical analysis. Results: The mean post-operative blood loss in the tranexamic acid group was 272.5±122.5 ml (mean±SD), and 685±118.2 ml in the placebo group (P<0.001). The total blood loss was lower in the tranexamic acid group than in the placebo group (427.6 ml vs. 911.6 ml; P<0.001). The absolute number of blood transfusions and the number of patients who required transfusions were lower in the tranexamic acid group than in the placebo group. None of the patients had any side or adverse effect. Conclusions: Tranexamic acid significantly decreases post-operative blood loss and reduces the need for blood transfusion in patients undergoing TKR.

Context: Blood culture is routinely taken at the time of admission to the intensive care unit (ICU) for patients suspected to have infection. We undertook this study to determine the incidence of bacteremia at the time of ICU admission and to assess its impact on the outcome. Methods: Retrospective cohort study from all the admissions in ICU, in whom blood cultures sent at the time of admission were analyzed. Data regarding patient demographics, probable source of infection, previous antibiotic use and ICU course was recorded. Severity of illness on admission was assessed by acute physiology and chronic health evaluation II score. Statistical Analysis: Qualitative data were analyzed using Chi-square or Fisher Exact test and quantitative data were analyzed using Student's t-test. Primary outcome measure was ICU mortality. Results: Of 567 patients, 42% patients were on antibiotics. Sixty-four percent of the patients were direct ICU admission from casualty, 10.76% were from wards and 6.17% from other ICUs, and 19.05% were transfers from other hospitals. Blood cultures were positive in 10.6% patients. Mortality was significantly higher in patients with positive blood cultures (45% vs. 13.6%; P=0.000). On univariate analysis, only previous antibiotic use was statistically associated with higher mortality (P=0.011). Bacteremic patients who were already on antibiotics had a significantly higher mortality (OR 12.9, 95% CI: 1.6-100). Conclusions: Blood cultures may be positive in only minority of the patients with suspected infection admitted to ICU. Nevertheless, the prognosis of those patients with positive blood culture is worse, especially if culture is positive in spite of the patient being on antibiotics.

Background: Mixed drugs poisoning (MDP) is common in the emergency departments. Because of the limited number of intensive care unit beds, recognition of risk factors to divide the patients into different survival groups is necessary. Poisoning due to ingestion of different medications may have additive or antagonistic effects on different parameters included in the scoring systems; therefore, the aim of the study was to compare applicability of the different scoring systems in outcomes prediction of patients admitted with MDP-induced coma. Methods: This prospective, observational study included 93 patients with MDP-induced coma. Clinical and laboratory data conforming to the Acute Physiology and Chronic Health Evaluation (APACHE II), Modified APACHE II Score (MAS), Mainz Emergency Evaluation Scores (MEES) and Glasgow Coma Scale (GCS) were recorded for all patients on admission (time ₀ ) and 24 h later (time ₂₄ ). The outcome was recorded in two categories: Survived with or without complication and non-survived. Discrimination was evaluated using receiver operating characteristic (ROC) curves and area under the ROC curve (AUC). Results: The mortality rate was 9.7%. Mean of each scoring system was statistically significant between time ₀ and time ₂₄ in the survivors. However, it was not significant in non-survivors. Discrimination was excellent for GCS ₂₄ (0.90±0.05), APACHE II ₂₄ (0.89±0.01), MAS ₂₄ (0.86±0.10), and APACHE II ₀ (0.83±0.11) AUC. Conclusion: The GCS ₂₄ , APACHE II ₂₄ , MAS ₂₄ , and APACHE II ₀ scoring systems seem to predict the outcome in comatose patients due to MDP more accurately. GCS and MAS may have superiority over the others in being easy to perform and not requiring laboratory data.

Congenital afibrinogenemia is a very rare autosomal recessive disorder, results from mutation that affects plasma fibrinogen concentration. It is frequently associated with bleeding diathesis of varying severity. We describe the case of a 10-year-old child diagnosed of congenital afibrinogenemia who presented to hospital with subperiosteal haematoma and was posted for incision and drainage. Replacement therapy is the mainstay of treatment of bleeding episodes in this patient and plasma-derived fibrinogen concentrate is the agent of choice. Cryoprecipitate and fresh frozen plasma are alternative treatments. Appropriate amount of cryoprecipitate were transfused pre-operatively to the child. Individuals with congenital afibrinogenemia should be managed by a comprehensive bleeding disorder care team experienced in diagnosing and managing inherited bleeding disorders. Anaesthesiologist, surgeons and haematologist should work like a unit to manage the surgical emergencies.

We report prolonged desaturation in a child with Down syndrome (DS) and atrial septal defect due to undiagnosed interstitial lung disease. An 18-month-old child with DS was scheduled for bilateral lens aspiration for cataract. The child had atrial septal defect and hypothyroidism. He also had delayed milestones and hypotonia with episodes of recurrent respiratory tract infection necessitating repeated hospitalization. Preoperative evaluation was unremarkable. General anaesthesia and controlled ventilation using proseal laryngeal mask airway was instituted. He had uneventful intraoperative period. In the postoperative period, the child had desaturation 1 hour after surgery on discontinuation of oxygen supplementation by face mask, which improved with oxygen therapy. Supplemental oxygen via face mask was continued and weaned off over several days. On further evaluation, the child was diagnosed as having interstitial lung disease. He improved and discharged from the hospital 15 days after the surgery with room air saturation of 90%.

Anisocoria is an uncommon entity in general postoperative intensive care. We present a case of a 45-year-old man suffering from severe acute pancreatitis with a past history of traumatic brain injury (TBI), who developed hypertension, bradycardia and anisocoria soon after re-exploration surgery under general anaesthesia. Computed tomography showed no new lesion. Measures directed towards reducing intracranial pressure resulted in amelioration in about 12 h. The possible role of old TBI in the causation of anisocoria during general anaesthesia and resuscitation has been explored in this report.

Phaeochromocytoma is a rare cause of hypertension during pregnancy with potentially fatal consequences. If not detected and treated early in pregnancy, it is catastrophic for both the mother and the baby. Management requires close co-ordination between the obstetrician, anaesthesiologist, paediatrician and the endocrinologist. Perioperative management for an emergency caesarean section in a parturient with untreated phaeochromocytoma is an anaesthetic challenge and no standard recommendations have been reported till date. In this case report, we present anaesthetic management in such a case with successful maternal and foetal outcome.

Successful anaesthetic management for caesarean section in a case with previous pituitary tumour resection, with residual tumour, is reported. The pituitary gland undergoes global hyperplasia during pregnancy. Functional pituitary tumours may exhibit symptomatic enlargement during pregnancy. Growth hormone secreting tumour is associated with acromegaly which has associated anaesthetic implications of difficult airway, systemic hypertension, and diabetes and electrolyte imbalance. Intracranial space occupying lesions can increase intra cranial pressure and compromise cerebral perfusion or cause herniation. We report management of this case.

Administering anaesthesia to a patient with chronic schizophrenia is a challenge due to the increased risk of various perioperative complications. Neuroleptic agents are highly effective drugs used for the treatment of psychiatric disorders, but are rarely associated with neuroleptic malignant syndrome (NMS). Here, we describe the successful anaesthetic management of a patient of chronic schizophrenia with past history of NMS who presented in emergency with active bleeding per rectum and haemoglobin of 3 gm%.

A 2-month-old child presented with gross and huge swelling on the left side of the neck with difficulty in feeding. It was diagnosed to be cystic hygroma and a decision was made to excise the swelling to enable the child thrive better. Difficult intubation was anticipated and the child was intubated with inhalation induction. The intra-operative period was smooth and the tumour was excised completely. Post-operatively, it was decided to ventilate the child because of airway difficulties.