Behavioural insights and attitudes on community masking during the initial spread of COVID-19 in Hong Kong.

INTRODUCTION: Community face mask use during the coronavirus disease 2019 (COVID-19) pandemic has considerably differed worldwide. Generally, Asians are more inclined to wear face masks during disease outbreaks. Hong Kong has emerged relatively unscathed during the initial outbreak of COVID-19, despite its dense population. Previous infectious disease outbreaks influenced the local masking behaviour and response to public health measures. Thus, local behavioural insights are important for the successful implementation of infection control measures. This study explored the behaviour and attitudes of wearing face masks in the community during the initial spread of COVID-19 in Hong Kong. METHODS: We observed the masking behaviour of 10 211 pedestrians in several regions across Hong Kong from 1 to 29 February 2020. We supplemented the data with an online survey of 3199 respondents' views on face mask use. RESULTS: Among pedestrians, the masking rate was 94.8%; 83.7% wore disposable surgical masks. However, 13.0% wore surgical masks incorrectly with 42.5% worn too low, exposing the nostrils or mouth; 35.5% worn 'inside-out' or 'upside-down'. Most online respondents believed in the efficacy of wearing face mask for protection (94.6%) and prevention of community spread (96.6%). Surprisingly, 78.9% reused their mask; more respondents obtained information from social media (65.9%) than from government websites (23.2%). CONCLUSIONS: In Hong Kong, members of the population are motivated to wear masks and believe in the effectiveness of face masks against disease spread. However, a high mask reuse rate and errors in masking techniques were observed. Information on government websites should be enhanced and their accessibility should be improved.

Sonographic evaluation of diaphragmatic function during breathing control.

OBJECTIVE: To investigate the effect of "breathing control" on sonographic diaphragmatic excursion. METHOD: A prospective, randomized, assessor-blinded study design involving 20 physiotherapy students; ten with knowledge of the breathing control technique (Group BC) and ten without (Group CON). All participants were asked to perform a Chester step test. Group BC performed BC, while Group CON adopted their own breathing pattern during recovery after the step test. Respiratory rate and sonographic parameters of the diaphragm including diaphragmatic excursion, speed of diaphragmatic contraction (slope of contraction), and inspiratory time were recorded before and after the step test. RESULTS: All baseline data were similar for both groups except age. Respiratory rate at 1 min post-step test was higher in Group CON (24.6±4.9 bpm) compared to Group BC (15.6 ± 3.8 bpm) (p < 0.001). Post-step test sonographic evaluation demonstrated an increase in diaphragmatic excursion with a significant time and group interaction (F(4,72) = 5.499, p = 0.005). Post hoc analysis revealed that the diaphragmatic excursion was significantly higher in Group BC compared to Group CON at first, second and third minute post-step test. Time and group interactions were not significant in inspiration time (F(4,72) = 2.459, p = 0.082) nor the slope of contraction (F(4,72) = 0.655, p = 0.582)]. CONCLUSION: Post-exercise diaphragmatic excursion was higher in participants applying BC. Non-invasive ultrasonography is able to promote objective evaluation of the relationship between breathing techniques and diaphragmatic function.

Randomized trial of anaesthetic interventions in external cephalic version for breech presentation.

BACKGROUND: Successful external cephalic version (ECV) for breech presenting fetus reduces the need for Caesarean section (CS). We aimed to compare the success rate of ECV with either spinal anaesthesia (SA) or i.v. analgesia using remifentanil. METHODS: In a double-phased, stratified randomized blinded controlled study we compared the success rates of ECV, performed under spinal anaesthesia (SA), i.v. analgesia (IVA) using remifentanil or no anaesthetic interventions. In phase I, 189 patients were stratified by parity before randomization to ECV, performed by blinded operators, under SA using either hyperbaric bupivacaine 9 mg with fentanyl 15 µg, i.v. remifentanil infusion 0.1 µg kg min(-1), or Control (no anaesthetic intervention). Operators performing ECV were blinded to the treatment allocation. In phase 2, patients in the Control group in whom the initial ECV failed were further randomized to receive either SA (n=9) or IVA (n=9) for a re-attempt. The primary outcome was the incidence of successful ECV. RESULTS: The success rate in Phase 1 was greatest using SA [52/63 (83%)], compared with IVA [40/63 (64%)] and Control [40/63 (64%)], (P=0.027). Median [IQR] pain scores on a visual analogue scale (range 0-100), were 0 [0-0] with SA, 35 [0-60] with IVA and 50 [30-75] in the Control group (P<0.001). Median [IQR] VAS sedation scores were highest with IVA [75 (50-80)], followed by SA, [0 (0-50)] and Control [0 (0-0)]. In phase 2, 7/9 (78%) of ECV re-attempts were successful with SA, whereas all re-attempts using IVA failed (P=0.0007). The incidence of fetal bradycardia necessitating emergency CS within 30 min, was similar among groups; 1.6% (1/63) in the SA and IVA groups and 3.2% (2/63) in the Control group. CONCLUSIONS: SA increased the success rate and reduced pain for both primary and re-attempts of ECV, whereas IVA using remifentanil infusion only reduced the pain. There was no significant increase in the incidence of fetal bradycardia or emergency CS, with ECV performed under anaesthetic interventions. Relaxation of the abdominal muscles from SA appears to underlie the improved outcomes for ECV.

Haemodynamic effects of glycopyrrolate pre-treatment before phenylephrine infusion during spinal anaesthesia for caesarean delivery.

BACKGROUND: Phenylephrine given during spinal anaesthesia for caesarean delivery often induces a decrease in heart rate which may decrease cardiac output. Anticholinergic drugs may be given to attenuate this effect but may also cause more labile blood pressure. This study evaluated the effects of glycopyrrolate pre-treatment on non-invasively measured cardiac output and accuracy of blood pressure control. METHODS: At induction of spinal anaesthesia for caesarean delivery, 104 patients randomly received intravenous glycopyrrolate 4µg/kg or saline placebo. Systolic blood pressure, measured at 1-min intervals, was maintained near baseline using closed-loop feedback computer-controlled phenylephrine infusion with crystalloid cohydration. Cardiac output and stroke volume were measured using suprasternal Doppler ultrasonography at baseline and 5-min intervals for 20min. Blood pressure control was assessed using performance error calculations. RESULTS: Eleven patients were excluded. Patients who received glycopyrrolate (n=45) had greater cardiac output over time (P<0.001), greater heart rate over time (P<0.001), similar stroke volume over time (P=0.95), and lower median phenylephrine infusion rate (P=0.006) compared with control (n=48). There was no difference in the incidence of hypotension between groups. Analysis of blood pressure control showed greater positive bias, greater inaccuracy and greater wobble in the glycopyrrolate group (all P<0.05). Neonatal outcome was similar between groups. CONCLUSIONS: Glycopyrrolate 4µg/kg given at the start of a phenylephrine infusion increased heart rate and cardiac output but also decreased accuracy of blood pressure control, increased the incidence of hypertension and caused an increased incidence of dry mouth postoperatively compared with control.

Haemodynamic effects from aortocaval compression at different angles of lateral tilt in non-labouring term pregnant women.

BACKGROUND: Aortocaval compression (ACC) can result in haemodynamic disturbances and uteroplacental hypoperfusion in parturients. Its detection is difficult because in most patients, sympathetic compensation results in no signs or symptoms. However, profound hypotension may develop after sympathectomy during regional anaesthesia. In this prospective observational study, we aimed to detect ACC by analysing haemodynamic changes in term parturients who were positioned sequentially at different angles of lateral tilt. METHODS: We studied haemodynamic changes in 157 non-labouring term parturients who were positioned in random order at 0°, 7.5°, 15°, and full left lateral tilt. Cardiac output (CO), stroke volume, and systemic vascular resistance were derived using suprasternal Doppler. Non-invasive arterial pressure (AP) measured in the upper and lower limbs was analysed to detect aortic compression. RESULTS: CO was on average 5% higher when patients were tilted at ≥15° compared with <15°. In a subgroup of patients (n=11), CO decreased by more than 20%, without changes in systolic AP, when they were tilted to <15° which was considered attributable to severe inferior vena caval compression. Only one patient in the supine position had aortic compression with the systolic AP in the upper limb 25 mm Hg higher than the lower limb. CONCLUSIONS: Patients with ACC can be identified by the CO changes from serial measurements between supine, 15°, or full lateral tilt. Our findings suggest that in non-labouring parturients, ACC is asymptomatic and can be effectively minimized by the use of a left lateral tilt of 15° or greater.