Global warming refers to an average increase in the earth's temperature, which in turn causes changes in climate. A warmer earth may lead to changes in rainfall patterns, a rise in sea level, and a wide range of impacts on plants, wildlife, and humans. Greenhouse gases make the earth warmer by trapping energy inside the atmosphere. Greenhouse gases are any gas that absorbs infrared radiation in the atmosphere and include: water vapor, carbon dioxide (CO ₂ ), methane (CH ₄ ), nitrous oxide (N ₂ O), halogenated fluorocarbons (HCFCs), ozone (O ₃ ), perfluorinated carbons (PFCs), and hydrofluorocarbons (HFCs). Hazardous chemicals enter the air we breathe as a result of dozens of activities carried out during a typical day at a healthcare facility like processing lab samples, burning fossil fuels etc. We sometimes forget that anesthetic agents are also greenhouse gases (GHGs). Anesthetic agents used today are volatile halogenated ethers and the common carrier gas nitrous oxide known to be aggressive GHGs. With less than 5% of the total delivered halogenated anesthetic being metabolized by the patient, the vast majority of the anesthetic is routinely vented to the atmosphere through the operating room scavenging system. The global warming potential (GWP) of a halogenated anesthetic is up to 2,000 times greater than CO ₂ . Global warming potentials are used to compare the strength of different GHGs to trap heat in the atmosphere relative to that of CO ₂ . Here we discuss about the GWP of anesthetic gases, preventive measures to decrease the global warming effects of anesthetic gases and Xenon, a newer anesthetic gas for the future of anesthesia.

One of the most exiting recent technological advances in the field of anesthesia to track the region of interest is the introduction of anatomical evaluation by ultrasound imaging. Widespread use of this modality depends on its proven clinical efficacy, cost effectiveness, and practicality as it allows anesthesiologist to evaluate complex and varied anatomy prior to needle insertion. Sound used in medicine is not significantly transmitted by air or bone but through fluids which make up the larger part of soft tissues in the body. Ultrasound has been shown to offer excellent guidance for difficult venous access, epidural space identification in cases of difficult anatomy, delineating nerve plexuses for chronic nerve blocks, for regional anesthesia, and in transesophageal echocardiography for cardiac imaging with blood flows or in an otherwise high-risk patient where interventional procedure is required. It has special application to assess the narrowest diameter of the subglottic upper airway. A systemic literature search was performed in PubMed and the Cochrane library. The search strategy was set up using either single text word or combinations. We also included the studies where in these techniques were compared with conventional methods . Despite the initial excitement of this technique, ultrasound visualization is still indirect and images are subject to individual interpretation. It is gradually becoming routine in daily practice at our institution due to its reliability and safety. Though ultrasound is much safer, exposure in terms of intensity and time should be limited as far as possible, as high-energy ultrasound can cause heating and damage to tissues. In this review, we discuss established and future areas of ultrasound imaging and emphasize the use of B-mode ultrasound to improve the efficacy of interventional techniques. We have also illustrated potential uses with reference to cross-sectional B-mode images which visually represent a slice of tissues and are the easiest images for interpretation by clinicians.

Spinal cord stimulation (SCS) is thought to relieve chronic intractable pain by stimulating nerve fibers in the spinal cord. The resulting impulses in the fibers may inhibit the conduction of pain signals to the brain, according to the pain gate theory proposed by Melzack and Wall in 1965 and the sensation of pain is thus blocked. Although SCS may reduce pain, it will not eliminate it. After a period of concern about safety and efficacy, SCS is now regaining popularity among pain specialists for the treatment of chronic pain. The sympatholytic effect of SCS is one of its most interesting therapeutic properties. This effect is considered responsible for the effectiveness of SCS in peripheral ischemia, and at least some cases of complex regional pain syndrome. The sympatholytic effect has also been considered part of the management of other chronic pain states such as failed back surgery syndrome, phantom pain, diabetic neuropathy, and postherpetic neuralgia. In general, SCS is part of an overall treatment strategy and is used only after the more conservative treatments have failed. The concept of SCS has evolved rapidly following the technological advances that have produced leads with multiple contact electrodes and battery systems. The current prevalence of patients with chronic pain requiring treatment other than conventional medical management has significantly increased and so has been the need for SCS. With the cost benefit analysis showing significant support for SCS, it may be appropriate to offer this as an effective alternative treatment for these patients.

Introduction: During preoperative preparation, patients undergo investigations to detect asymptomatic diseases. The probability of finding significant abnormalities on such "routine" investigations is small, and these investigations unnecessarily increase costs of perioperative care. We evaluated current practices, compliance with national guidelines and costs of preoperative investigations at the National Hospital of Sri Lanka (NHSL). Materials and Methods: Patients undergoing elective surgery at the general surgical units of the NHSL from June to August 2010 were included in this study. The National Guidelines on Preoperative Investigations were the standard of assessment. Data on preoperative investigations were collected using an expert-validated pretested interviewer-administered questionnaire. Results: Sample size was 2,061 patients. Mean age of the patients was 46.7±15.8 years; males constituted 54.2% of the study population. Majority of the patients were ASA-I (68.5%) and surgical grade II (62.0%). Request for chest X-ray and prothrombin time / international normalized ratio least conformed to the guidelines. Only fasting blood sugar / random blood sugar demonstrated 'good' compliance (>70%) to the guidelines. An 'acceptable' compliance (50%-70%) was seen for electrocardiogram, blood grouping and full blood count. All other investigations demonstrated 'poor' compliance (<50%) with the guidelines. The total excess cost incurred due to non-recommended investigations during the study period of 3 months was Sri Lankan Rupees (LKR.) 1,324,860 to 2,044,210 (per patient LKR. 642.82-991.85). Intern house officers (IHOs) were involved in the planning of preoperative investigations in 2,001 patients (97.1%), followed by medical officer-anesthesia / registrar-anesthesia (n=1,625; 78.8%), surgical registrars (n=190; 9.2%), consultant (n=70; 3.4%), senior registrar (n=46; 2.2%) and senior house officers (n=22; 1.1%). Non-recommended investigations were requested mostly by the IHOs and medical officer-anesthesia / registrar-anesthesia. Conclusions: Unnecessary preoperative investigations are common at our institution, leading to substantially excessive costs. There is ample opportunity to rationalize practices and reduce expenditure.

Background: Propofol (2,6-di-isopropylphenol) used for the induction of anesthesia often causes mild to severe pain or discomfort on injection, for which various methods have been tried, but with conflicting results. Objective: The present study involved pretreatment with lignocaine, fentanyl and placebo for prevention of pain on propofol injection to determine the difference in efficacy of fentanyl 100 μg compared with lignocaine 40 mg. Materials and Methods: Sixty-three participants of either sex, between 18 and 60 years of age, belonging to ASA physical status 1 and 2, undergoing elective surgery under general anesthesia, were randomized into three equal groups of 21 participants. They received, intravenously, either lignocaine (20 mg/mL) or fentanyl (50 μg/mL) or placebo (normal saline 2 mL) pretreatment before the propofol injection. Results: The three groups were comparable with respect to age, height, weight, sex and ASA physical status. The incidences of pain on pretreatment drug injection was higher in the fentanyl group (33.3%) compared with lignocaine and normal saline (P<0.05). The lowest incidence of pain on propofol injection was observed in the lignocaine pretreatment group (14.3%) compared with fentanyl (42.9%) and normal saline (71.4%) (P<0.05). There was no significant difference in adverse skin reaction within groups. In the normal saline pretreatment group, 38.1% of the participants experienced severe pain, compared with 9.5% in the fentanyl (P<0.05) group; none with lignocaine. The number needed to treat was 2 in the lignocaine pretreatment group compared with 4 in the fentanyl pretreatment group. Conclusion: Compared with fentanyl, lignocaine pretreatment was more effective in preventing pain on propofol injection.

Introduction/Context: A comparative study was carried out to evaluate the analgesic efficacy and side effects of addition of fentanyl to local anesthetic undergoing surgeries on forearm and elbow. All patients were hemodynamically stable, and there were no serious side effects in any of the patients in both the groups. The difference in the mean duration of analgesia between the groups was statistically significant (P<0.01). So we can conclude- Addition of Fentanyl to local anaesthetic in brachial plexus block increases duration of analgesia. Materials and Methods: Patients were randomly divided into two groups: group I (control) and group II (study). All the patients were subjected to brachial plexus block with supraclavicular approach. After obtaining paraesthesia, drugs were administered as follows: Group I (control): bupivacaine 0.5% 20 mL + lignocaine 2% 10 mL + NS 1 mL Group II (study): bupivacaine 0.5% 20 mL + lignocaine 2% 10 mL + fentanyl 1 mL (50 microgm). Observations were noted. All the relevant information was recorded on a pretested, predefined, semi-open pro forma sheet. Regular monitoring of PR, BP and RR, side effects,degree of sedation were recorded. Evaluation of pain and pain relief was done according to McGill pain questionnaire (0- no pain to 5- excruciating pain). When patients complained of discomforting pain (McGill grade II), parenteral analgesic was prescribed, and the total number of doses in the 24-hour period was noted. Results: The duration of analgesia in group II (study) was significantly longer (695±85 min) than those in group I (415±78 min). However, onset time of analgesia was prolonged in group 2. We conclude that the addition of fentanyl to local anesthetics causes an improved success rate of sensory blockade but a delayed onset of analgesia, although this may be accounted for by the decreased pH caused by fentanyl. There was no statistically significant difference in the incidence of side effects between the two groups. Conclusions: This study has shown that the mean duration of analgesia is extended if fentanyl is added to local anesthetics, without increasing the side effects.

Background: In this study, we compared the sedative effects of sublingual midazolam solution with the oral tablet as premedication. Sixty pediatric patients of ASA physical status I and II were randomly selected to receive either 0.5 mg/kg of tablet or 0.5 mg/kg of sublingual solution of midazolam as premedication, about 45 min before elective surgery. Materials and Methods: There were 30 patients in each group. In Group I, the patients received premedication in the form of oral midazolam tablet 0.5 mg/kg. In Group II, the patients received midazolam solution 0.5 mg/kg. The degree of sedation and ease of separation was assessed according to the Niall C. Wilton scale and the procedure of Davis Peter, respectively. The time for complete drug dissolution was noted in both the groups. Then, the patients were interviewed regarding their acceptance of taste. Results: The sedation scores in the sublingual group were higher than in the oral group at 30 and 45 min after drug administration (P=0.0134 and P=0.0157). 66.6% of the patients in the sublingual group found it satisfactory as compared to 53.3% in the case of group receiving tablet. Conclusion: Thus, from the present study, it is concluded that premedication with midazolam is more effective by the sublingual than the oral route in children.

Background: Intubating Laryngeal Mask Airway (ILMA) is a relatively new device designed to have better intubating characteristics than the standard Laryngeal Mask Airway. This study was designed to compare Intubating Laryngeal Mask with standard Direct Laryngoscopy (DLS), taking into account ease of intubation, time taken for intubation, success rate of intubation, hemodynamic responses and upper airway morbidity. Materials and Methods: Sixty patients, ASA I or II, of age between 20 and 60 years, were enrolled in this prospective and randomized study. They were randomly allocated to one of the two groups: group ILMA, Intubating Laryngeal Mask Airway; group DLS, Direct Laryngoscopy. The patients were intubated orally using either equipment after induction of general anesthesia. Results and Conclusions: DLS is comparatively a faster method to secure tracheal intubation than Intubating Laryngeal Mask. ILMA offers no advantage in attenuating the hemodynamic responses compared to direct laryngoscope. The success rate of intubation through Intubating Laryngeal Mask is comparable with that of DLS. The upper airway morbidity and mean oxygen saturation are comparable in both the groups.

Background: Hemodynamic responses of laryngoscopy, intubation, and pain are powerful noxious stimulus which should be attenuated by the appropriate premedication, smooth induction, and rapid intubation. Context: The oral pregabalin may attenuate the hemodynamic pressor response with intraoperative hemodynamic stability. Aims: The present study was designed to evaluate the clinical efficacy and safety of oral pregabalin for hemodynamic stability. Settings and Design: This is a prospective blind randomized controlled cohort observation study. Materials and Methods: The 80 adult consented patients of ASA grade I and II of either gender aged 24-54 years who met the inclusion criteria were randomized to receive oral pregabalin 150 mg or placebo capsule, given 60-75 min before surgery. Patients were premedicated with metoclopramide (10 mg), glycopyrrolate (0.2 mg), and fentanyl (1 μg/kg). Anesthesia was induced with propofol and rocuronium and maintained with isoflurane, nitrous oxide, and oxygen. Both groups were assessed for preoperative sedation and changes in heart rate and mean arterial blood pressure before and after the induction and 1, 3, 5, and 10 min after laryngoscopy and intubation, then at 5 min intervals till end of surgery along with postoperative complications. Statistical Analysis: The hemodynamic variables were analyzed by using analysis of variance (ANOVA), Student's t test, and chi square test as appropriate. Results: Preoperative sedation was higher with pregabalin with no significant change in heart rate. The mean arterial pressure was attenuated with oral pregabalin to statistically significant value (P<0.007). The requirement of analgesic drug was reduced with no postoperative respiratory depression, nausea, or vomiting and hemodynamic parameters remained stabilized perioperatively. Conclusions: Oral pregabalin premedication effectively leads to sedation and analgesia with successful attenuation of the adverse and deleterious hemodynamic pressor response.

Context: For rhinoplasty, full control of facial symmetry will improve the aesthetic results. During rhinoplasty, the nasal intubation is contraindicated while oral intubation may interfere with surgical procedure. Hence an alternative airway option of the submental intubation was planned to study the efficacy of the procedure. Aims: The submental intubation may improve the aesthetic results of rhinoplasty and facial symmetry. Setting and Design: This is a prospective cohort observational study. Materials and Methods: Fifteen adult consented patients of ASA grade I and II of either gender aged 20 to 38 years who met the inclusion criteria were enrolled. After induction, orotracheal intubation was done with flexometallic tube, followed by a 1.5-cm skin incision in the submental region, adjacent to lower border of mandible;then endotracheal tube was taken out through this incision. At the end of surgery, the procedure was reversed and submental wound was stitched. Patients were extubated after proper suctioning of oral cavity. No intraoperative and postoperative complications have occurred. Results: The submental intubation was performed in 15 patients by medial approach without any difficulty. The average time taken to perform the procedure was 7.27±0.63 min. No anesthetic and surgical complications were encountered in any patients. The submental scar was almost invisible after 2 months. Conclusion: Submental intubation offers a secure airway, efficient ventilation, and uninterrupted operating field to the plastic surgeon. Lack of anesthesia and surgical complications encouraged us to present the advantages of submental intubation on the basis of our own experience.

Background: Ensuring adequate preoperative sedation and anxiolysis is essential, especially in pediatric surgery. Various drugs and routes of administration have been evaluated to determine the optimal method of sedation. Materials and Methods: We selected hundred preschool children undergoing elective surgery and sedated them with either intranasal midazolam or oral promethazine syrup in the preoperative period. They were assessed with respect to their levels of sedation till the period of mask placement for induction of general anesthesia. Results: Both groups had comparable heart rates, respiratory rates, sedation scores, and emotional scores at all points of assessment (P>0.05). However, intranasal midazolam had a significantly shorter onset of sedation as well as time to reach maximal sedation (P<0.001). Conclusion: We conclude that either drug may be used with ease in preschool children undergoing elective surgery.

Background: Hypotension after subarachnoid block is a common adverse event which can be predicted by simple, safe and indirect measure of autonomic activity. Context: Heart rate variability has been accepted as an indirect measure of autonomic activity. Aim : It was to evaluate preoperatively risk of hypotension after subarachnoid block. Setting and Design: This is controlled, randomized blind prospective study. Materials and Methods: One hundred adult patients of either sex in the age group of 25 to 60 years belonging to ASA physical status of I to III, scheduled for elective infra-umbilical surgery, were enrolled for this randomized prospective study. During preanesthetic check their HRV was analyzed for time domain and frequency domain parameters. They were classified into two groups of 50 patients each depending on their low to high frequency ratios (LF/HF). Group I included patients with LF/HF <2.5 and Group II included patients with LF/HF >2.5. Sensitivity of LF/HF for prediction of hypotension greater than 20% of baseline was tested. Result: The present study showed significant differences of systolic blood pressure (SBP) after subarachnoid block, depending on baseline LF/HF. Patients with low LF/HF showed lowest SBP of 106.08 ± 3.19 (15.22% fall of base line SBP) as compared to high LF/HF which showed 87.62 ± 8.71 (30.26% fall of base line SBP). Baseline LF/HF parameter correlated significantly with proportionate decrease in SBP after subarachnoid blocks. Statistical Analysis: Hemodynamic parameter was analyzed by using student t test on statgraphic version 5.1. Conclusion: Analysis of low and high frequency ratio, reflect autonomic control and may be used as an indirect measure for risk stratification of hypotension after subarachnoid block with high sensitivity.

Background: The prevalence of persistent chronic pain after abdominal hysterectomy is 5-32%. Our objectives were to determine the influence of transversus abdominis plane (TAP) block on the incidence of acute and chronic post-hysterectomy pain and to examine potential associations between time of block administration, either before surgical incision (preemptive) or after end of surgical procedure and its effect. Materials and Methods: Seventy-five patients undergoing elective total abdominal hysterectomy under general anesthesia were allocated randomly to receive TAP block either pre-incisional, or before emergence from anesthesia or sham block (just a needle puncture, control group). Pain was evaluated postoperatively at rest and movement by visual analogue scale. Peri-operative analgesic requirements, sedation, postoperative nausea and vomiting scores were recorded. Patients were questioned at three, and six months after surgery for type and severity of chronic pain. Results: Pain scores were significantly higher in Group II versus Group I (P<0.05), but both demonstrated significantly lower pain scores than control Group. Analgesic requirements decreased significantly in patients received TAP block (P<0.0001) with more significant decrease in the pre-incisional group. The incidence of chronic pain was significantly reduced in the pre-incisional group than others. The incidence of sedation was noted to be higher in the control group (61%) versus other groups (18% and 32% respectively), at time point 12 h postoperatively but was comparable between 12, 48 h (awake and alert). Incidence of postoperative nausea and vomiting (PONV) was reduced in patients who received TAP block (16% and 29%) in Group I and II respectively versus 66.5% in Group III. There were no complications attributed to the TAP block. Conclusions: TAP block seems to be an acceptable choice for postoperative analgesia; pre-incisional TAP block appeared to reduce the severity of acute pain, analgesic requirements with its undesirable side-effects and incidence of chronic pain in comparison with blockade before emergence from anesthesia.

Aim: This study was to identify the safety and efficacy of adding epidural N-methyl-D-aspartate receptor antagonists (ketamine) to oral gabapentin for the treatment of post spinal cord injury-related chronic pain. Materials and Methods: Forty patients in the age range of 18-50 years with a diagnosis of neuropathic pain secondary to spinal cord injury were randomized into two equal groups. Group I received 0.2 mg/Kg of preservative-free ketamine (2 ml) single bolus epidural injection and gabapentin 300 mg three times daily. Group II received isotonic saline 0.9% (2 ml) single bolus epidural injection and gabapentin 300 mg three times daily. Pain scores were evaluated pre-injection, 7, 15, 30,45 and 60 days post injection. Patients were asked about any side-effects occurred during follow-up period. Results: At all time points examined, pain scores were significantly lower in both groups than pre-injection values (P < 0.0001). Pain scores were significantly lower in Group I than in Group II at 7, 15, 30 days after injection (P 0.02, < 0.0001, =0.0001 respectively), but no statistically significant difference was detected between groups at 45, 60 days post injection (P = 0.54, =0.25), there was no statistically significant difference regarding incidence of side-effects in both groups. Conclusion: Epidurally administrated ketamine seems to be a safe adjunct to gabapentin in post spinal cord injury-related chronic pain. However, its analgesic efficacy was limited to 30 days after injection.

Background: Ketamine-induced hemodynamic pressor response and psychomimetic effects should be attenuated by appropriate premedication. The present study was designed to evaluate the clinical efficacy and safety of dexmedetomidine premedication for balancing the ketamine-induced hemodynamic pressor response and psychomimetic effects. Materials and Methods: A total of 80 normotensive adult consented patients of ASA grade I and II of both genders, aged 21 to 55 years, who met the inclusion criteria for elective surgery under ketamine anesthesia were randomized for this prospective blind study and divided into two treatment groups of 40 patients each. Group I patients received premedication of midazolam and Group II patients received premedication of dexmedetomidine. Anesthetic and surgical techniques were standardized. Both groups were assessed for changes in heart rate and systolic blood pressure intraoperatively and psychomimetic effects with behavioral changes postoperatively. Results: Preoperatively, all patients were awake. Intraoperatively, the heart rate was 116.6±4.2 in group I versus 76.8±5.8 in group II (P value 0.0004) and systolic blood pressure was 153.07±16.05 in group I versus 139.17±19.9 in group II (P value 0.001). Post-anesthetic psychomimetic responses were not statistically significant between groups. Conclusion: The dexmedetomidine premedication effectively attenuated the ketamine induced hemodynamic pressor response and post-anesthetic delirium effects.

A young adult presented with signs of peritonitis following tube thoracostomy for suspected acute hydropneumothorax. Attempted decompression of the chest by tube thoracostomy had caused gastric perforation, and on surgical exploration, he was found to have a congenital diaphragmatic hernia with herniation of the stomach, spleen and colon. All intensive care doctors and emergency room physicians dealing with the care of patients with acute respiratory failure should be taught to recognize and keep the possibility of a Bochdalek hernia in mind, especially in young adults presenting with unusual respiratory and gastrointestinal symptoms.

Cushing's syndrome is uncommon in pregnancy, and Cushing's disease being the cause for this syndrome is still rare. We had the opportunity to manage such a patient admitted for cesarean section. Here, we describe the evaluation of a patient with Cushing's syndrome in pregnancy along with its anesthetic implications. By describing this case, we intend to emphasize the role of the anaesthesiologist as a peri operative physician.

Takayasu's arteritis (TA) is a rare, chronic progressive pan-endarteritis involving the aorta and its main branches. Anesthesia for patients with TA is complicated by severe uncontrolled hypertension, end-organ dysfunction, stenosis of major blood vessels, and difficulties in monitoring arterial blood pressure. We present the successful anesthetic management of a 23-year-old woman having TA with bilateral subclavian and renal artery stenosis posted for emergency cesarean section by using the epidural volume extension technique, which offers the combined advantage of both spinal and epidural anesthesia and, at the same time, also avoids the need of sophisticated neurological monitors like EEG and transcranial Doppler.

Symmetrical peripheral gangrene (SPG) is a devastating complication seen in critical care settings due to several contributory factors like low perfusion, high dose of vasopressors, disseminated intravascular coagulation, etc. Arterial cannulation is commonly done in critical patients for monitoring. We report a case of patient who developed early features of SPG which recovered in one hand, although it progressed in the hand which had the arterial cannula.

Hydatidosis is a parasitic infection caused by the encysted larvae of Echinococcus granulosus, commonly called as hydatid cyst. Almost all organs can be involved, but most commonly it affects liver (55%-70%) followed by the lungs (18%-35%). The surgery and anesthetic management become very challenging if these cysts are in or near the vicinity of vital organs, such as heart. Pulmonary hydatid cysts may rupture into the bronchial tree or pleural cavity and produce cough, chest pain, or hemoptysis and there are chances of injury to heart if the cyst is in close proximity to it. We are describing the successful management of such a case of pulmonary and hepatic hydatid cyst in a young female patient.