A cross-sectional overview of the second 4000 incidents reported to webAIRS, a de-identified web-based anaesthesia incident reporting system in Australia and New Zealand

This cross-sectional overview of the second 4000 incidents reported to webAIRS has findings that are very similar to the previous overview of the first 4000 incidents. The distribution of patient age, body mass index and American Society of Anesthesiologists physical status was similar, as was anaesthetist gender, grade, location and time of day of incidents. About 35% of incidents occurred during non-elective procedures (vs. 33% in the first 4000 incidents). The proportion of incidents in the various main categories was also similar, with respiratory/airway being most common, followed by cardiovascular, medication-related and medical device or equipment-related incidents. Together these categories made up about 78% of all incidents in both overviews. The immediate outcome was comparable with reports of harm in about a quarter of incidents and a similar rate of deaths (4.7% vs. 4.2%). However, the proportion of patients who had received total intravenous anaesthesia was higher (17.6% vs. 7.7%) and the proportion of patients who received combined intravenous and inhalational anaesthesia was lower (52.3% vs. 58.4%), as was the proportion receiving local anaesthesia alone (1.6% vs. 6.7%). There was a small increase in the number of incidents resulting in unplanned admission to a high dependency or intensive care unit (18.1% vs. 13.5%). It is not clear whether these differences represent trends or random observations. About 48% of incidents were considered preventable by the reporters (vs. 52% in the first 4000). These findings support continued emphasis on human and system factors to promote and improve patient safety in anaesthesia care.

To observe the changes of optic nerve sheath diameter following the use of total intravenous anaesthesia with propofol or inhalational anaesthesia with desflurane during laparoscopic surgeries

Optic nerve sheath diameter measurement is a simple, non-invasive and yet accurate intracranial pressure (ICP) assessment technique during laparoscopic surgery. The pneumoperitoneum induced by insufflating carbon-dioxide and steep angle of trendelenburg position is associated with physiological changes resulting in increased ICP during laparoscopic surgery. We aimed to observe the changes of ONSD (surrogate marker of ICP) following the use of total intravenous anaesthesia in comparison to desflurane during laparoscopic surgery.Patients scheduled for elective laparoscopic surgery were randomly assigned to the TIVA or DES group in this randomized study. Ultrasonographic measurements of ONSD were conducted before administration of anaesthesia (T0), 10 mins, 30 mins, 1 hr after the trendelenburg position (T1,T2,T3), 5mins after resuming the supine position (T4) and at post-anaesthetic care unit (T5). The primary outcome measure was the comparison of the mean ONSD of both the eyes of the patients of both the groups that is TIVA versus DES (inhalational anaesthetic) group.A total of 60 patients were analysed in our study. The mean ONSD value at T1, T2, T3 and T4 (for right eye p=0.002,0.001,<0.01,0.03 respectively and for left eye p=0.004,<0.01,<0.01,0.02 respectively) were significantly lower for patients in TIVA group as compared with those in DES group.Our result suggests that TIVA may be a better option than inhalational anaesthesia to prevent rise in intracranial pressure in patients undergoing laparoscopic surgery and preventing devastating complications caused by raised intracranial pressure in succeptible patients.

Dramatic demise of a pregnant woman in third trimester after presenting with persistent headache: An iatrogenic

A 31-years-old patient, pregnant at 32 weeks of gestation presented to our triage unit with complaint of gradually progressive persistent headache that started 1 day earlier and was unresponsive to all analgesics. Her history was insignificant for any major medical or surgical events and the pregnancy course was smooth as well. Her lab results and obstetric ultrasound were reassuring. During magnetic resonance imaging examination, the patient suddenly deteriorated after giving her an inhalational anaesthesia for sedation. She became unconscious. She was intubated, mechanically ventilated, and put-on cardiovascular support. Brain imaging then revealed Brain Stem (BS) herniation and diffuse brain oedema. She was announced dead with intrauterine foetal death. A late diagnosis of cerebral venous thrombosis was established. This caused BS herniation through increased intracranial pressure, which was iatrogenically augmented by administering inhalation anaesthesia. Keywords: cerebral vein; thrombosi; thrombophilia; pregnancy; headache; magnetic resonance imaging; brain stem herniation.

Newer Volatile Anesthetic Agents in Cardiac Anesthesia: Review of Literature

Myocardial protection with volatile anesthetic agents have been suggested by multiple studies. These studies, however, are scattered and are often limited to a particular aspect of cardiac anesthesia. Older inhalational agents like halothane is known to cause significant hepatic damage in patients undergoing long duration surgeries while isoflurane is known to have marked vasodilating properties that also affects the coronary arteries leading to coronary “steal” phenomenon. Additionally, newer agents, like sevoflurane and desflurane, have shown more prominent cardioprotective effects than older agents. We searched ScholarOne, Medline, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library. The medical subject headings (MeSH) terms “anaesthesia, inhalational,” “anaesthesia, intravenous, or TIVA,” and “Cardiac anaesthesia or Cardiac Surgery” were used. Additional studies were identified by review of the reference sections of all eligible studies. The aim of this review article is to bring together the evidences with newer inhalational agents and provide a holistic view of their benefits and shortcomings in cardiac anesthesia.

Effects of esmolol infusion on cardiovascular parameters and quality of general anaesthesia in younger and older patients

Background: Esmolol is a cardioselective b-adrenergic antagonist that is used during general anaesthesia to blunt the sympathetic reflex tachycardia and hypertension. The aim of the study was to investigate whether the potential beneficial and adverse effects of esmolol differ depending on the patient age. Methods: A total of 50 ASA I/II patients scheduled for elective upper abdominal surgery were divided in two groups: younger (patients aged up to 35 years) and older (patients older than 65). After premedication with Diazepam, they were infused with esmolol during the first 5 min at a rate of 0.3 mg/kg/min and 0.1 mg/kg/min thereafter. Anaesthesia was induced with thiopental sodium 3-5 mg/kg intravenously (iv) and fentanyl 1.5 µg/kg IV. Tracheal intubation was facilitated with suxamethonium 1-2 mg/kg IV. Long-term neuromuscular blockade was induced with pancuronium bromide 0.07 mg/kg IV bolus and maintained with incremental IV boluses of 0.01 mg/ kg. Inhalational anaesthesia was maintained with a mixture of oxygen and nitrous oxide (O2 /N2 O) 2 : 1. Results: The systolic blood pressure remained constant during the intubation phase in the group of older patients, at the same time being around 89 % of the pre-induction values, while in younger patients it rose up to 100 %. During the same phase of anaesthesia, the diastolic blood pressure in older patients remained at about 91 %, while in younger patients it rose up to 107 % of the pre-induction values. The consumption of drugs and the speed and quality of the recovery from anaesthesia did not differ between the two groups of patients. Conclusion: Infusion of esmolol contributes to the concept of general balanced anaesthesia in elective patients scheduled for upper abdominal surgery equally in younger and older patients.

Ectothermy and cardiac shunts profoundly slow the equilibration of inhaled anaesthetics in a multi-compartment model

The use of inhalational anaesthesia is ubiquitous in terrestrial vertebrates. Given the dependence of these agents on delivery by the cardiorespiratory system, we developed a new computational model predicting equilibration of inhaled anaesthetics in mammalian and ectotherm conditions including the ability of reptiles to maintain vascular shunts. A multi-compartment model was constructed from simultaneously-solved equations, verified by comparison to the literature for endo and ectotherm physiology. The time to 90% equilibration of anaesthetic in arterial blood (t90) is predicted and used to compare anaesthetics and physiologies. The five to tenfold lower cardiac output and minute ventilation of ectothermic vertebrates is predicted to slow equilibration times by five to ten times leading to 90% equilibration in ectotherm arterial blood of over 200 min, compounded by reduction in body temperature, and the extent of right-to-left vascular shunts. The impact of these findings is also influenced by the solubility coefficient of the anaesthetic, such that at net right-to-left shunt fractions of over 0.8, sevoflurane loses the advantage of faster equilibration, in comparison with isoflurane. We explore clinical strategies to regulate anaesthetic uptake in ectotherms by managing convectional flow especially by supportive ventilation and reduction of the right-to-left shunt.