External compression headache during Covid-19 pandemic: a neglected entity

Introduction : Personal Protective Equipment (PPE) is part of the work routine of health professionals, especially during pandemics. During the Covid-19 pandemic, the use of PPE became constant for long working hours, resulting in adverse effects on the health of professionals, especially headache. Objective : In this review, we explore the scientific literature on headache associated with prolonged use of PPE during the coronavirus pandemic. Method : This is a narrative literature review conducted through the PubMed and Web of Science databases according to the following MeSH descriptors: “Face shield”, “Headache” and “Covid-19”. Articles that analyzed the presence of headache and other adverse events in health professionals in prolonged use of PPE were included. Results : The included studies point to headache as the most prevalent adverse event, which may be a new headache or the worsening of a previous headache. Other effects were also found, such as pressure marks on the skin, hyperemia in contact areas; suffocation; reduced concentration and excessive sweating. Conclusion : The use of PPE for long periods can cause headaches due to external pressure, in addition to other unwanted events.These effects reveal the importance of studies to make PPE more efficient, ensuring protection for the individual without causing discomfort.


Introduction
D uring the Covid-19 pandemic, Personal Protective Equip- ment (PPE) played a substantial role in the contagion and spread of the coronavirus. 1During this period, the use of N95 masks, face shields, goggles, aprons, and gloves set became mandatory, constant, and for long consecutive hours of work.
Among the equipment used, the N95 mask is the most widespread and effective in protecting against contaminating droplets. 2Together, the face shield offers a promissory safety additive, preventing physical contact with the eyes, mouth, and regions from the nose. 3However, with prolonged use, PPE has been associated with a broad spectrum of adverse effects, from skin depression to headaches. 4The mask and goggles are the equipment most often associated with external pressure headaches due to pressure points on the scalp. 5erefore, this review aims to explore headaches as an adverse effect of prolonged use of PPE, both in the appearance of new headaches and the worsening of pre-existing headaches.

Methods
This is a narrative literature review conducted in the PubMed and Web of Science databases during January 2021, using the descriptors "Headache", "Mask N95", "Face shield", "Protective Goggles", and " Personal Protective Equipment" in combination with the Boolean operator AND.
We included original articles published between January 1, 2019, and December 31, 2020, in English, Portuguese, or Spanish, which addressed headaches as an adverse event related to PPE use in the care of patients infected with the coronavirus.Literature reviews, letters to the editor, short communications, conferences, and editorial abstracts were excluded.
The selection of studies was performed by two independent researchers (E.R.R.S. and E.C.O.R.).Divergences were adjusted in a consensual manner.To ensure the validity of these articles, selected studies were analyzed in detail for demographic and clinical characteristics.

Results
Of the 38 studies found, after the review procedure, 13 duplicates were identified and blindly removed.After reading the titles and abstracts, 15 were also excluded for not meeting the eligibility criteria.Finally, 10 articles were included in the final evaluation and analysis of results (Figure 1).Most studies had a cross-sectional design (70%) and were conducted in Asian countries (60%) (Table 1).All studies identified headaches as one of the events most reported by health professionals in prolonged use of PPE (Table 2).Among the equipment studied, the N95 mask was the most prevalent (100%), followed by goggles (60%) and face shields (30%).A combination of PPE was present in only 30% of the studies (Table 2).
Headache was associated with wearing protective eyewear and face shields for more than four hours (p < 0.05). 5These findings are corroborated by Tabah et al., who observed the presence of headaches according to the time of use of PPE.In shifts shorter than 3h, 18% of individuals reported headache, in shifts longer than 3h, this prevalence progressively increased from 31% to 35%, reaching its maximum in shifts longer than 9h.In univariate logistic regression, this result was presented with an Odds Ratio of 1.13 for each hour of use of PPE (p < 0.001). 6anges in cerebral hemodynamics were also identified by one study.Bharatendu et al. compared the results of transcranial middle cerebral artery Doppler in subjects before and during the use of the N95 mask.A significant increase in mean flow velocity (p < 0.001) and a significant reduction in pulse index (p < 0.001) were observed.End-tidal carbon dioxide (ET-CO2) pressure also showed a significant increase during PPE use (p < 0.001). 7e results of the studies associated the use of PPE both with the appearance of new headaches and with the worsening of existing headaches.New headaches were observed in 28-80% of the individuals analyzed, while previous headaches were identified in 21-25% of these individuals. 7,8 aheer et al. found a mostly bilateral (69%), pressure (45.5%) and moderate intensity (69%) pattern in new headaches.8Furthermore, individuals previously suffering from headaches have been identified with increased susceptibility to headache induction by EPI. 8,9 artín-Rodríguez et al. 10 analyzed possible biomarkers in the prediction of head- External compression headache during Covid-19 pandemic: a neglected entity aches associated with the use of PPE. 10 Among the analyzed parameters, creatinine was found to be significantly elevated in individuals who developed headaches after 4 hours of use of PPE compared to individuals who did not (p = 0.019 ). 10 In addition to headaches, the included studies also pointed to psychosocial and work-related effects.Agarwal et al. observed the presence of excessive sweating (100%), fogging of glasses, (88%) suffocation (83%), shortness of breath (61%), fatigue (75%), and pressure marks on the skin (19%) in individuals after prolonged use of PPE. 11Other symptoms such as reduced concentration and professional performance have also been reported. 6,12,13

Discussion
In the present review, headache proved to be a prevalent adverse event during prolonged use of PPE, with the most likely etiology being external compression of superficial nerves in the scalp and face.The most reported sites of pain were the frontal and temporal (bilateral) regions, coinciding with the contact areas of PPE anchorages. 4,8,12 TN95 mask and face shield exert pressure primarily on the occipitofrontal and temporalis muscles and their innervations.Figure 2 demonstrates the relationship between the EPI pressure points and the territory of the cutaneous nerves of the head, branches of the trigeminal nerve, and cervical spinal nerve.This pain mechanism configures the classification of "External compression headache" in the International Classification of Headache Disorders (ICHD-3), described as a "Headache resulting from continued compression of pericranial soft tissues; for example, by a tight band around the head, hat, helmet, or goggles used for swimming or diving, without scalp damage". 14Table 3 summarizes the diagnostic criteria for this type of headache.Among the uncommon primary headaches, external compression headache is still poorly studied.7] The results of our review corroborate previous data on headaches with prolonged use of N95 masks.In a study carried out during the Severe Acute Respiratory Syndrome epidemic in 2003, 37.3% of individuals reported headaches after prolonged use of N95 masks, of which 32.9% reported a frequency of more than six episodes per month. 16e use of a mask for long periods also causes superficial skin lesions, due to the pressure exerted on the soft tissues of the face and head, leaving marks on the upper part of the nose, zygomatic region, and ear. 1,5 tudies have shown that the mask The N95 face mask effectively protects against respiratory droplets, but the material that composes it, such as the metal clip, can cause abrasions on the nasal bridge, followed by a prolonged painful sensation of the facial tissues. 18,19Other mask components, such as the thick stitching on the cheek area and two elastic bands that wrap around the head and the neck can intensify the discomfort.
The design and materials used in the manufacture of PPE have already been criticized in surgical practice, a previous study identified impaired performance in the operating room (54%), difficulty in visualizing (63%), communication problems (54%), increased fatigue during surgery (82%), suggesting more attention in the manufacture of this equipment. 20In another study, nurses and respiratory therapists also suggested improvements in mask design, such as size, shape, straps, nose clip, and odor, the latter being the most mentioned. 21e mask can also impair breathing due to CO2 levels increase and hemodynamic changes. 7,9,13,17 Ths increase in carbon dioxide can also cause changes in heart rate and blood pressure, leading to the symptom of fatigue observed in our review. 9 In 12 hours of an average work period, the PPE change can occur on average twice.However, depending on the conditions, there may be an uninterrupted use. 11In these cases, professionals often change the position of the equipment in an attempt to alleviate the pain points, generating more comfort for the individual at the expense of a greater risk of contamination (Figure 3).

Conclusion
Adverse events associated with the prolonged use of PPE such as an N95 mask, face shield, and goggles range from physical and cosmetic (observed in the skin tissue in contact with the mask material) to the most worrying cases of headache associated with the use prolonged use of equipment or exacerbation of pre-existing headache.These can affect the performance of the health professional, as well as their occupational health.Given the current Covid-19 scenario and the results of this review, we recommended investment in improving protective equipment.Other measures that may minimize these events are: avoiding the prolonged use of PPE at work, avoiding long working hours, and improving equipment design.

Figure 2 .
Figure 2. Relationship between PPE straps and cutaneous nerves of the head, trigeminal nerve branches, and cervical spinal nerve branches.The marked regions correspond to the nervous territories: ophthalmic branch of

A
At least two episodes of headache fulfilling criteria B-D B Provoked by and occurring within an hour during continued external compression of the forehead or scalp C Maximum at the site of external compression D Disappearing within an hour after external compression is relieved E Not better explained by another ICHD-3 diagnosis.

Figure 3 .
Figure 3. Combined use of N95 mask and face shield; (3a) Correct use of face shield; (3b) Incorrect use of face shield.Note that in order to relieve pressure in the frontal region, the face shield was incorrectly positioned.Image: created by the authors.

Table 1 .
Studies included in the review

Table 1 .
Studies included in the review