FALL3D-8.0: a computational model for atmospheric transport and deposition of particles, aerosols and radionuclides – Part 2: model applications

This manuscript presents different application cases and validation results of the latest version release of the FALL3D-8.0 model, an open-source atmospheric transport model. The code has been redesigned from scratch to incorporate different categories of species and to overcome legacy issues that precluded its preparation towards extreme-scale computing. Validation results are shown for long-range dispersal of fine volcanic ash and SO2 clouds, tephra fallout deposits and dispersal and ground deposition of radionuclides. The first two examples (i.e. the 2011 Puyehue-Cordón Caulle and 2019 Raikoke eruptions) make use of geostationary satellite retrievals for two purposes: first, to furnish an initial data insertion condition for the model; and second, to validate the time series of model outputs against the satellite retrievals. The metrics used to validate the model simulations of volcanic ash and SO2 are the Structure, Amplitude and Location (SAL) metric and the Figure of Merit in Space (FMS). The other two application cases are validated with scattered ground-based observations of deposit load and local particle grain size distributions from the 23 February 2013 Mt. Etna eruption and with measurements from the Radioactivity Environmental Monitoring (REM) database during the 1986 Chernobyl nuclear accident. Simulation results indicate that FALL3D-8.0 outperforms previous code versions both in terms of model accuracy and code performance. We also find that simulations initialised with the new data insertion scheme consistently improve agreement with satellite retrievals at all lead times out to 48 hours for both SO2 and long-range fine ash simulations.

A Comparative Study of Smooth Insertion of Laryngeal Mask Airway with Propofol and Thiopentone Combined with Midazolam

Background: Successful insertion of Laryngeal Mask Airway (LMA) requires sufficient depth of anesthesia and depression of airway reflexes to avoid gagging, coughing and laryngeal spasm. The LMA is popular because it is easy to insert and it provides a secure airway for the patients who breathe spontaneously. Indeed, the intravent LMA instruction manual specifically recommends propofol for induction of anesthesia during LMA insertion. As a matter of fact Propofol and LMA insertion has become synonymous. However, there are some problems related to the use of propofol, for example, relatively high cost. This observational study was conducted to compare efficacy and safety of propofol and thiopentone -midazolam in smooth insertion of LMA and the hemodynamic changes over time in both groups. Methods: The study was done in the Department of Anesthesiology, Chittagong Medical College from July, 2012 to December, 2013. All the patients scheduled for elective surgical procedures under general anesthesia fulfilling the inclusion criteria, were the study population. Data was analyzed by computer based software SPSS-21. Results: Overall LMA insertion condition was improved better by the use of midazolam with thiopentone sodium (Group B) than propofol (Group A). The drug regime used in group A (Propofol) was expensive than group B (midazolam with thiopentone sodium) with indifferent hemodynamic stability in both groups. Mean ages of patients were 32.43 years ± SD- 10.67 years in group A and 33.5 years ± SD- 10.63 years in group B. Conclusion: In the perspective of our study, for smooth insertion of LMA midazolam-thiopentone sodium regime is cheaper and can be effectively and safely used over propofol regime. Chatt Maa Shi Hosp Med Coll J; Vol.17 (1); Jan 2018; Page 38-41

Comparative Study of Propofol Versus Thiopental Sodium with Succinylcholine for Laryngeal Mask Airway (LMA) Insertion

Background: The increasing emphasis on day case anaesthesia has lead to the greater use of the laryngeal mask airway (LMA) as an alternative to intubation. Laryngoscopy and tracheal intubation are noxious stimuli, which cause a reflex increase in both sympathetic and sympathoadrenal activity that may result in tachycardia, hypertension and dysarrhythmias. Insertion of Laryngeal mask airway (LMA) is associated with less haemodynamic changes, minimal increase in intraocular and intracranial pressure and lower incidence of sore throat. Still its insertion requires sufficient depth of anesthesia to prevent airway reflex (gagging, coughing nd spasms). To insert LMA successfully propofol is the most frequently administered medication. But most of all recommend not using propofol singly for LMA insertion. Thiopental can’t suppress the upper airway reflexes as propofol but with low dose succinylcholine upper airway reflexes are attenuated so combination of thiopental sodium with succinylcholine may be another choice of drug.Objectives: This Prospective study was conducted to evaluate the effectiveness of Thiopental sodium and Succinylcholine for insertion of the LMA in comparison with Propofol.Methods: This interventional study was carried out in Sixty patients, aged 3-45 years who were scheduled for elective surgical procedure under general anaesthesia in ShSMCH. Patients were randomly assigned to two groups by odd and even number basis. In Group-1 (N1=30), LMA was inserted after induction with Thiopental sodium (5 mg/kg body weight i.v.) and Succinylcholine (0.5mg/kg i.v); in Group-2 (N2 = 30), the LMA was inserted with Propofol (2.5mg/kg i.v). Jaw relaxation, incidence of coughing- gagging , overall insertion condition and haemodynamic changes were observed.Results: Grade of jaw relaxation in Group-1 was Good in 93.3%, incomplete in 6.7% and 0% poor but in Group-2, 86.7% was good 10% incomplete and 3.3% was poor. Coughing occurred in 33.3% of patients in the Group-2 and there was only 10% in succinyl group (P=0.028) which is significantly higher in Group-2. Overall insertion condition in Group -1 was excellent in 86.7%, Good in 10% cases and poor in only 3.3% cases on the other hand in Group-2 excellent in 53.3%, Good in 33.3% cases and poor in only 13.3% cases (P=0.019).Conclusion: There was statistically significant difference in jaw relaxation in two groups and incidence of Gagging or Coughing is higher in Group-2. Overall insertion condition was significantly better in Group-1. We concluded that Thiopental sodium with low dose Suxamethonium is an effective alternative of Propofol.J Shaheed Suhrawardy Med Coll, June 2018, Vol.10(1); 11-15

Assessment of effect of various concentration of ketamine-propofol (ketofol) on haemodynamic parameters and LMA insertion conditions

Background: The purpose of this study is to compare the effect of various concentration of ketamine-propofol (ketofol) on LMA insertion condition and hemodynamic parameters.Methods: Hundred patients of ASA I, II, aged between 18-65 years, were randomized in group A, B, C and D, each consist of 26, 25, 25, 24 patients respectively. They were premedicated with injection GPL, injection midazolam, injection fentanyl and induced with ketofol in 1:1, 1:2, 1:3 and 1:4 ratio in Group A, B, C, D respectively. 60 seconds after induction LMA insertion condition including mouth opening, swallowing, coughing, head and body movements, laryngospasm, ease of LMA insertion, apnea time, and time of LMA insertion were recorded. They were scored 1 to 3. Hemodynamic parameters- heart rate, noninvasive blood pressure and SPO2 were recorded before induction (T1), immediately following induction (T2), immediately after LMA insertion (T3), 5mins after LMA insertion (T4) and 10 mins after LMA insertion (T5).Results: Total 100 patients were included in this prospective randomized double-blind study between April 2017 to March 2018. Pulse rate at (T3) was significantly lower (P-0.06) in group C and D. Diastolic BP was found lower at (T2) time (P-0.04) in group C and D. Apnea time was longest in group A (P-0.002) LMA insertion time was minimum in group B (P-0.008).Conclusions: Addition of low dose of ketamine in propofol favour LMA insertion, due to opposite effect on muscle tone, better relaxation but heart rate, blood pressure remains stable with 1:1, 1:2 ratio of ketofol.