Influence of Face Masks on Physiological and Subjective Response during 130 Min of Simulated Light and Medium Physical Manual Work-An Explorative Study.

BACKGROUND: Undesirable side effects from wearing face masks during the ongoing COVID-19 pandemic continue to be discussed and pose a challenge to occupational health and safety when recommending safe application. Only few studies examined the effects of continuously wearing a face mask for more than one hour. Therefore, the influence of wearing a medical mask (MedMask) and a filtering facepiece class II respirator (FFP2) on the physiological and subjective outcomes in the course of 130 min of manual work was exploratively investigated. Physical work load and cardiorespiratory fitness levels were additionally considered as moderating factors. METHODS: Twenty-four healthy subjects (12 females) from three different cardiorespiratory fitness levels each performed 130 min of simulated manual work with light and medium physical workload using either no mask, a MedMask or FFP2. Heart rate, transcutaneous oxygen and carbon dioxide partial pressure (PtcO2, PtcCO2) as well as perceived physical exertion and respiratory effort were assessed continuously at discrete time intervals. Wearing comfort of the masks were additionally rated after the working period. RESULTS: There was no difference in time-dependent changes of physiological outcomes when using either a MedMask or a FFP2 compared to not wearing a mask. A stronger increase over time in perceived respiratory effort occurred when the face masks were worn, being more prominent for FFP2. Physical workload level and cardiorespiratory fitness level were no moderating factors and higher wearing comfort was rated for the MedMask. CONCLUSION: Our results suggest that using face masks during light and medium physical manual work does not induce detrimental side effects. Prolonged wearing episodes appeared to increase respiratory effort, but without affecting human physiology in a clinically relevant way.

Save our surgeons (SOS) - an explorative comparison of surgeons' muscular and cardiovascular demands, posture, perceived workload and discomfort during robotic vs. laparoscopic surgery.

PURPOSE: Conventional laparoscopic surgery (CLS) imposes an increased risk of work-related musculoskeletal disorders. Technical innovations, such as robotic-assisted laparoscopic surgery (RALS), may provide ergonomic benefits. We compare the surgeon`s work-related demands of CLS vs RALS for benign hysterectomies. METHODS: Five specialists (3 females, 2 males) each performed four RALS and four CLS as part of their daily clinical routine. During the surgical procedures, muscular demands were assessed by bipolar surface electromyograms of the descendent trapezius, extensor digitorum and flexor carpi radialis muscles as well as cardio-vascular demands by electrocardiography, and neck, arm and torso posture by gravimetrical position sensors. Additionally, the subjects rated their level of perceived workload (NASA TLX questionnaire with 6 dimension) and musculoskeletal discomfort (11-point Likert-scale, 0-10). RESULTS: Muscular demands of the trapezius and flexor carpi radialis muscles were lower with RALS but extensor digitorum demands increased. Cardiovascular demands were about 9 heart beats per minute (bpm) lower for RALS compared to CLS with a rather low median level for both surgical techniques (RALS = 84 bpm; CLS 90 bpm). The posture changed in RALS with an increase in neck and torso flexion, and a reduction in abduction and anteversion position of the right arm. The perceived workload was lower in the physical demands dimension but higher in the mental demands dimension during RALS. Subjective musculoskeletal discomfort was rare during both surgical techniques. CONCLUSIONS: This explorative study identified several potential ergonomic benefits related to RALS which now can be verified by studies using hypothesis testing designs. However, potential effects on muscular demands in the lower arm extensor muscles also have to be addressed in such studies.

Effects of a Passive Back-Support Exoskeleton on Knee Joint Loading during Simulated Static Sorting and Dynamic Lifting Tasks.

Due to the load shifting mechanism of many back-support exoskeletons (BSEs), this study evaluated possible side effects of using a BSE on knee joint loading. Twenty-nine subjects (25.9 (±4.4) years, 179.0 (±6.5) cm; 73.6 (±9.4) kg) performed simulated static sorting and dynamic lifting tasks, including stoop and squat styles and different trunk rotation postures. Ground reaction force, body posture and the force between the chest and the BSE's contact interface were recorded using a force plate, two-dimensional gravimetric position sensors, and a built-in force sensor of the BSE, respectively. Using these parameters and the subject's anthropometry, median and 90th percentile horizontal (HOR50, HOR90) and vertical (VERT50, VERT90) tibiofemoral forces were calculated via a self-developed inverse quasi-static biomechanical model. BSE use had a variable effect on HOR50 dependent on the working task and body posture. Generally, VERT50 increased without significant interaction effects with posture or task. HOR90 and VERT90 were not affected by using the BSE. In conclusion, utilizing the investigated exoskeleton is likely to induce side effects in terms of changed knee joint loading. This may depend on the applied working task and the user's body posture. The role of these changes in the context of a negative contribution to work-related cumulative knee exposures should be addressed by future research.

Effects of Face Masks on Physical Performance and Physiological Response during a Submaximal Bicycle Ergometer Test.

The ongoing COVID-19 pandemic requires wearing face masks in many areas of our daily life; hence, the potential side effects of mask use are discussed. Therefore, the present study explores whether wearing a medical face mask (MedMask) affects physical working capacity (PWC). Secondary, the influence of a filtering facepiece mask with exhalation valve class 2 (FFP2exhal) and a cotton fabric mask (community mask) on PWC was also investigated. Furthermore, corresponding physiological and subjective responses when wearing face masks as well as a potential moderating role of subjects' individual cardiorespiratory fitness and sex on face mask effects were analyzed. Thirty-nine subjects (20 males, 19 females) with different cardiorespiratory fitness levels participated in a standardized submaximal bicycle ergometer protocol using either a MedMask, FFP2exhal, community mask, or no mask (control) on four days, in randomized order. PWC130 and PWC150 as the mechanical load at the heart rates of 130 and 150 beats per minute were measured as well as transcutaneous carbon dioxide partial pressure, saturation of peripheral capillary oxygen, breathing frequency, blood pressure, perceived respiratory effort, and physical exhaustion. Using the MedMask did not lead to changes in PWC or physiological response compared to control. Neither appeared changes exceeding normal ranges when the FFP2exhal or community mask was worn. Perceived respiratory effort was up to one point higher (zero-to-ten Likert scale) when using face masks (p < 0.05) compared to control. Sex and cardiorespiratory fitness were not factors influencing the effects of the masks. The results of the present study provide reason to believe that wearing face masks for infection prevention during the COVID-19 pandemic does not pose relevant additional physical demands on the user although some more respiratory effort is required.

Ergonomics for surgeons - prototype of an external surgeon support system reduces muscular activity and fatigue.

BACKGROUND: Since the unergonomic postures cannot be changed during a surgery, it seems reasonable to externally support the surgeon's posture in order to relieve the musculature. To evaluate this matter, we conducted a pilot study to investigate if a prototype of an external surgeon support system (S3) relieves the musculature in an objectively measurable manner. METHODS: Simultaneous surface electromyography (EMG) was used alongside a combination of a laser Doppler flowmeter and a tissue spectrometer to record back and leg muscles during a simulated surgical situation. FINDINGS: With S3, muscle activity was significantly lower (p < 0.05) and also fatigue decreased when compared to without S3. Muscle blood flow and oxygenation were relatively close to baseline with S3, but increased without S3. INTERPRETATION: An ergonomic S3 is a possible approach to reduce muscle activity and fatigue and may therefore prevent chronic back pain amongst surgeons in the long term.

Long-term cardiopulmonary function after thoracic sympathectomy: comparison between the conventional and simplified techniques.

OBJECTIVE: We sought to compare the long-term effects of conventional and simplified thoracic sympathectomy on cardiopulmonary function. METHODS: We performed a prospective and randomized study of 32 patients with diagnoses of primary hyperhidrosis who were candidates for either conventional or simplified thoracic sympathectomy. Patients were randomized according to the type of procedure: conventional thoracic sympathectomy (18 patients) and simplified thoracic sympathectomy (14 patients). Before surgical intervention, forced spirometry, body plethysmography, measurement of the diffusing capacity of the lung for carbon monoxide (DLCO), and exercise tests were carried out in all patients. These evaluations were performed again 1 year after the procedure to assess the long-term effects of sympathectomy. RESULTS: Lung function tests revealed a significant decrease in forced expiratory volume in 1 second (FEV(1)) and forced expiratory flow between 25% and 75% of vital capacity (FEF(25%-75%)) in both groups (FEV(1) of -6.3% and FEF(25%-75%) of -9.1% in the conventional thoracic sympathectomy group and FEV(1) of -3.5% and FEF(25%-75%) of -12.3% in the simplified thoracic sympathectomy group). DLCO and heart rate at rest and maximal values after exercise were also significantly reduced in both groups (DLCO of -4.2%, DLCO corrected by alveolar volume of -6.1%, resting heart rate of -11.8 beats/min, and maximal heart rate of -9.5 beats/min in the conventional thoracic sympathectomy group and DLCO of -3.9%, DLCO corrected by alveolar volume of -5.2%, resting heart rate of -10.7 beats/min, and maximal heart rate of -17.6 beats/min in the simplified thoracic sympathectomy group). Airway resistance increased significantly in the group of patients undergoing conventional thoracic sympathectomy (+13%). Despite all these changes, the patients remained asymptomatic. No significant differences were found between the conventional and simplified thoracic sympathectomy groups. CONCLUSIONS: Simplified and conventional thoracic sympathectomy resulted in a long-term reduction in FEV(1), FEF(25%-75%), DLCO, and resting and maximal heart rate, as well as a mild but significant increase in airway resistance in the conventional thoracic sympathectomy group, without any clinical consequence to the patient. These changes were unrelated to the level of transection of the thoracic sympathetic chain.