Emissions and atmospheric processes influence the chemical composition and toxicological properties of urban air particulate matter in Nanjing, China.

Ambient inhalable particulate matter (PM) is a serious health concern worldwide, but especially so in China where high PM concentrations affect huge populations. Atmospheric processes and emission sources cause spatial and temporal variations in PM concentration and chemical composition, but their influence on the toxicological characteristics of PM are still inadequately understood. In this study, we report an extensive chemical and toxicological characterization of size-segregated urban air inhalable PM collected in August and October 2013 from Nanjing, and assess the effects of atmospheric processes and likely emission sources. A549 human alveolar epithelial cells were exposed to day- and nighttime PM samples (25, 75, 150, 200, 300 µg/ml) followed by analyses of cytotoxicity, genotoxicity, cell cycle, and inflammatory response. PM10-2.5 and PM0.2 caused the greatest toxicological responses for different endpoints, illustrating that particles with differing size and chemical composition activate distinct toxicological pathways in A549 cells. PM10-2.5 displayed the greatest oxidative stress and genotoxic responses; both were higher for the August samples compared with October. In contrast, PM0.2 and PM2.5-1.0 samples displayed high cytotoxicity and substantially disrupted cell cycle; August samples were more cytotoxic whereas October samples displayed higher cell cycle disruption. Several components associated with combustion, traffic, and industrial emissions displayed strong correlations with these toxicological responses. The lower responses for PM1.0-0.2 compared to PM0.2 and PM2.5-1.0 indicate diminished toxicological effects likely due to aerosol aging and lower proportion of fresh emission particles rich in highly reactive chemical components in the PM1.0-0.2 fraction. Different emission sources and atmospheric processes caused variations in the chemical composition and toxicological responses between PM fractions, sampling campaigns, and day and night. The results indicate different toxicological pathways for coarse-mode particles compared to the smaller particle fractions with typically higher content of combustion-derived components. The variable responses inside PM fractions demonstrate that differences in chemical composition influence the induced toxicological responses.

Factors controlling the evaporation of secondary organic aerosol from α-pinene ozonolysis.

Secondary organic aerosols (SOA) forms a major fraction of organic aerosols in the atmosphere. Knowledge of SOA properties that affect their dynamics in the atmosphere is needed for improving climate models. By combining experimental and modeling techniques, we investigated the factors controlling SOA evaporation under different humidity conditions. Our experiments support the conclusion of particle phase diffusivity limiting the evaporation under dry conditions. Viscosity of particles at dry conditions was estimated to increase several orders of magnitude during evaporation, up to 109 Pa s. However, at atmospherically relevant relative humidity and time scales, our results show that diffusion limitations may have a minor effect on evaporation of the studied α-pinene SOA particles. Based on previous studies and our model simulations, we suggest that, in warm environments dominated by biogenic emissions, the major uncertainty in models describing the SOA particle evaporation is related to the volatility of SOA constituents.

Teaching anaesthesia induction to medical students: comparison between full-scale simulation and supervised teaching in the operating theatre.

BACKGROUND AND OBJECTIVE: The aim of the study was to compare the effectiveness of teaching of general anaesthesia induction to medical students using either full-scale simulation or traditional supervised teaching with patients in the operating theatre. METHODS: Forty-six fourth year students attending their course in anaesthesiology were enrolled. The students were randomly assigned to two groups. The simulation group received training in the simulator. The traditional training group was supervised by a senior consultant anaesthetist. After the training sessions all students were tested in the simulator setting. The test was assessed using a 40-item evaluation list. RESULTS: Thirty-three per cent of students in the traditional group and 87% of the students in the simulation group passed the test. Statistically significant differences were: request of glycopyrrolate (P < 0.001), Sp(O2) monitoring (P < 0.001), used gloves when placing an intravenous cannula (P = 0.012), intubation attempt within 30 s (P < 0.04), anaesthesia gas set at MAC at least 1 (P < 0.04), instructed anaesthetic nurse to keep Sp(O2) at least 95% (P < 0.05), keep MAP at least 60 mmHg (P < 0.05), keep heart rate more than 50 beats per minute (P < 0.002), keep end-tidal p(CO2) 4-5.5 kPa (P < 0.002). CONCLUSION: The simulation group performed better in 25% of the tasks and similarly in the others compared with the traditional teaching group. With the same time and amount of teaching personnel we trained five or six students in the simulator compared with one student in the operating theatre. Further research will reveal whether these promising results with simulation may be applied more generally in anaesthesiology teaching to medical students.

Influence of medical direction on the management of prehospital myocardial infarction.

Prehospital management of myocardial infarction was evaluated in two differently structured Emergency Medical Service (EMS) systems in Southern Finland: a physician directed EMS with on-site physician involvement (physician EMS) and an EMS without operational physician involvement with paramedics only (non-physician EMS). The management of 641 consecutive acute ST-elevation myocardial infarction (STEMI) patients between 1997 and 1999 (263 patients in the physician EMS group and 378 patients in non-physician EMS group) were studied. Patients treated in the physician EMS received all necessary medical care including thrombolytic therapy at the scene whereas patients in the non-physician EMS were transported to hospital for definitive treatment after initial care. There were no differences in the demographics of the patients. The delays from onset of pain to initiation of thrombolysis were shorter in the physician EMS-group (124+/-101 min (25-723) versus 196+/-150 min (12-835), p<0.001). In 2% of the patients in the physician EMS group the pain to therapy-time was unknown compared to 27% in the non-physician EMS group (p<0.001). Fifty-two patients (20%) in the physician EMS received thrombolytic therapy after cardiopulmonary resuscitation compared to two patients in the non-physician EMS (p<0.001). Of the resuscitated patients in the physician directed EMS group 60% were discharged from the hospital, and 44% of these had a good neurological recovery. We conclude that a physician directed EMS is able to reduce the pain to therapy delays significantly in STEMI patients and may offer thrombolytic therapy to a wider patient group compared to an EMS without operational medical involvement.

Quality of life of elderly patients after prehospital thrombolytic therapy.

We studied the long-term outcome and quality of life of elderly patients after prehospital thrombolysis to treat acute ST-elevation myocardial infarction. Data of 218 patients after prehospital thrombolytic therapy given by two physician staffed Helicopter Emergency Medical Service (HEMS) units were collected prospectively. Physical and mental status was evaluated at 4--6 months after discharge, and 1-year mortality was determined. Patients older than 65 years were compared with those younger than 65 years. There were 112 elderly and 106 younger patients. The elderly patients had more previous coronary events and more medications. Pain to therapy times between the two groups were equal (<65 years: 108+/-93 min (range 27--500 min) versus >65 years: 108+/-70 min (20-357 min)). After 4--6 months, the Barthel Daily Living Index or the Beck Depression Inventory (BDI) (depression, if BDI >/=10) showed no differences between the two groups (<65 years: 99+/-5 (range 65--100) versus >65 years: 98+/-12 (10--100); BDI>/=10, 18% versus 9%). One-year survival was lower among the elderly (79% versus 93%; p=0.001). No differences in the frequency of arrhythmias, haemodynamic problems during thrombolysis or complications such as intracranial haemorrhage after thrombolysis were detected. We concluded that elderly patients treated with prehospital thrombolysis for acute ST-elevation myocardial infarction recover mentally and physically as well as younger patients.

Prehospital thrombolysis perfomed by a ship's nurse with on-line physician consultation.

Prehospital thrombolysis for acute ST-elevation myocardial infarction (STEMI) has been shown to improve recovery from myocardial function. We describe prehospital thrombolytic treatment in two patients suffering from STEMI complicated by ventricular fibrillation (VF) on a passenger ship. The importance of a functioning Emergency Medical Service (EMS) system providing guidance for paramedical personnel is discussed briefly. Both our patients survived and returned back to normal life. It is concluded that EMS physician guided prehospital thrombolytic treatment may offer an important therapeutic option for nurses or paramedics in locations out of reach of ordinary EMS services.

Arrhrythmias and haemodynamic effects associated with early versus late prehospital thrombolysis for acute myocardial infarction.

The occurrence of arrhythmias and haemodynamic changes was studied prospectively in 226 consecutive patients who received prehospital thrombolysis for acute ST-elevation myocardial infarction (STEMI) in two Helicopter Emergency Medical Service (HEMS) systems in Southern Finland. Of the 226 patients, 129 were classified as receiving early (pain to treatment-time <90 min) and 97 as late (pain to treatment-time >90 min) treatment. Data on all arrhythmias and haemodynamic disturbances during the prehospital phase were collected. Arrhythmias occurred in 39% of all patients (40% in the early and 38% in the late group). A third of the patients received treatment for their arrhythmia (38% in the early group and 24% in the late group, P = NS). The most common arrhythmia was ventricular extrasystoles, which did not require any treatment in the majority of patients. On arrival of the EMS crew, 14% of all patients were hypotensive (14% in the early and 13% in the late group). After thrombolytic treatment, 7% of all patients became hypotensive (7% of the patients in both groups). The most common treatment for hypotension was fluid administration. Of the 15 patients who received thrombolysis after cardiopulmonary resuscitation (CPR), four patients suffered from arrhythmias and six patients developed hypotension after initiation of thrombolytic treatment. Although arrhythmias and haemodynamic changes were frequent in the prehospital setting after initiation of thrombolytic therapy, severe adverse events were rare. Those requiring therapeutic measures responded well to treatment. The occurrence of events was not related to the timing of thrombolysis in relation to the duration of pain.

Prehospital ECG transmission: comparison of advanced mobile phone and facsimile devices in an urban Emergency Medical Service System.

OBJECTIVE: To compare the speed and reliability of electrocardiogram (ECG) transmissions from the prehospital setting to a conventional table facsimile device and to an advanced mobile phone in a Helicopter Emergency Medical Service System (HEMS). METHODS: Eighteen authentic ECGs stored in the memory module of a monitor defibrillator were used. The ECGs were (1) sent directly from the monitor defibrillator to a table fax and an advanced mobile phone at the HEMS base; (2) printed out and sent from a mobile fax connected to an ordinary mobile phone to the table fax and the advanced mobile phone at the HEMS base; (3) printed out and sent from an ordinary table fax as well as from a table fax connected to a satellite phone system to the receiving devices at the HEMS base. RESULTS: When the ECGs were sent from the table fax via satellite, the transmission times were longer to the advanced mobile phone than to the table fax at the HEMS base (1 min 54 s+/-0 min 21 s vs. 1 min 37 s+/-0 min 20 s, (mean+/-SD), (P<0.01). Regarding transmission from the other fax devices, there were no differences in transmission times between the two receiving devices. The fastest way to transmit ECGs to the advanced mobile phone was to send it from conventional table fax (1 min 22 s+/-0 min 18 s) and the longest transmission times were with mobile fax connected to mobile phone (5 min 23 s+/-3 min 5 s). In all ECGs transmitted except one the cardiac rhythm and ST-changes could be recognised. CONCLUSION: An advanced mobile phone is as fast and reliable as a conventional table fax in receiving ECGs. A mobile phone with advanced features is a practical tool for HEMS physicians who need to evaluate ECGs in the prehospital setting.