Role of the Physiotherapist in COVID-19

Please note: this is a rapidly developing topic and while we will try to keep this page up to date please let us know if you are aware of any new information or evidence that should be incorporated into this page. (30/11/2022)

Introduction[edit | edit source]

This content has been generously supported by World Physiotherapy

Physiotherapists who work in primary healthcare facilities will likely play a part in the management of patients admitted to hospital with confirmed or suspected COVID-19.[1]

Because of this direct contact with patients, physiotherapists and other clinicians are susceptible to the transmission of infectious diseases. Physiotherapists are also often first contact practitioners, which means that they are in a position to take responsibility for the early identification of infectious disease and/or managing workload in primary care settings. It is therefore very important for physiotherapists and other health professionals to be familiar with COVID-19 and how to prevent its transmission, and understand how they can be involved in workforce planning. They must use their professional judgment to determine when, where, and how to provide care, with the understanding that this is not always the optimal environment for care, for anyone involved[2]. At the same time, consideration must be given to the fact that our profession plays a crucial role in the health of our society, and there are people in our communities whose health will be significantly impacted by disruptions to care.

Key considerations:

  1. Stay current - Ensure that you are well-read on current COVID-19 guidance. The WHO and the CDC have good evolving resources. You can also check with your local authority for additional resources.
  2. Stay calm - Have an objective view of the crisis we are facing. People, for example, staff and patients, may look to you as a leader to provide information to help them make decisions and also provide reassurance that we can take care of them during this time of need.
  3. Minimise exposure in your setting - Review infection prevention and control (IPC) guidelines, practice social distancing,[3] implement triage strategies, reschedule non-urgent care, consider digital service delivery,[4] consider closures, for example, if you don't have PPE available.
  4. Get involved in workforce planning - Where appropriate, offer services to assist in reducing the load on emergency departments and frontline practitioners.
  5. Get educated - All staff should be trained in COVID-19 related strategies and procedures, including rehearsals of potential scenarios, such as a COVID-19 case being identified on the clinic premises.

It is important to keep in mind that physiotherapists work in many different settings. Although IPC will be the same for everyone and any setting can potentially contribute to reducing the workload of hospitals, the role of the physiotherapist in each setting may differ. In primary care (i.e. private clinics, physician shared or GP practices) the emphasis will be triage and early identification of cases. In community care (i.e. in the home) the emphasis will be on educating patients and caregivers. In acute care (i.e. the hospital setting) the emphasis will be on the management of respiratory symptoms.

Primary (Clinic) Care[edit | edit source]

There are two main considerations in primary care:

  1. Avoid transmission
  2. Provide education

Avoid Transmission[edit | edit source]

To avoid the transmission of COVID-19, the following are recommended practices for clinical staff:

1. Adhere to basic protective measures at all times

  • Perform hand hygiene frequently with an alcohol-based hand rub if your hands are not visibly dirty or with soap and water if hands are dirty.
  • Avoid touching your eyes, nose and mouth.
  • Practice respiratory hygiene by coughing or sneezing into a bent elbow or tissue and then immediately disposing of the tissue.
  • Based on current advice, the following people should wear medical masks:
    • Healthcare workers
    • People who are experiencing COVID-19 symptoms
    • Those looking after people with confirmed or suspected COVID-19
    • People aged 60+ and those with underlying health conditions (where COVID-19 is widespread and social distancing of at least 1m cannot be achieved)
  • Based on current advice, people should wear fabric masks when:
    • COVID-19 is widespread
    • Social distancing of greater than 1m cannot be achieved
    • Those in close contact with others

[5]

  • Maintain social distancing (a minimum of 1 m/3 ft[6]) and according to the CDC at least 2m/6ft from individuals with respiratory symptoms [7].
  • Seek medical care if you have a fever, cough or have difficulty breathing


2. Promote respiratory, hand and clinic hygiene

  • Ensure that you have appropriate written infection prevention and control protocols in your practice setting and communicate these protocols to all staff.
  • Place additional signage in and around the clinic to encourage regular hand washing. You can get these from the NIH (National Institutes of Health).
  • Ensure that alcohol-based hand sanitisers and/or handwashing stations are available.
  • Ensure regular cleaning and disinfection of the clinic and equipment, especially after attendance by a COVID-19 patient.


3. Provide up-to-date information about the virus to staff and patients

  • Share educational messages with patients.
  • Review and amend information on your clinic website, appointment reminders and appointment protocols.
  • Signage, about hand and respiratory hygiene and other basic protective measures, should be displayed prominently at the first point of contact to the service such as reception areas and waiting rooms. Signage should also prompt visitors, staff, volunteers and patients to self-identify if they are at risk of having COVID-19.

4. Avoid unnecessary direct physical contact with individuals who may be infected

  • Don't perform physical assessments.
  • Avoid exposure to respiratory secretions.
  • Encourage patients with symptoms to stay at home.


5. Liaise with staff and local public health specialists

  • Stay up to date with the latest information on the COVID-19 outbreak through WHO updates or your local and national public health authority.
  • Liaise with local public health specialists to keep up to date with local guidelines.
  • Hold regular team meetings with staff to review this information and provide any updates.


6. Initiate early identification strategies

If your clinic remains open, physiotherapists should undertake active screening (asking questions) and passive screening (signage) of patients for COVID-19.

- On booking an appointment

If an individual phones to make an appointment or has concerns about COVID-19 in advance of attending an appointment, they should be asked if they have had:

  • recent travel to places with presumed ongoing community transmission of COVID-19.
  • recent contact with anyone with confirmed COVID-19.
  • recent work in or visits to a healthcare facility where patients with confirmed COVID-19 were being treated.

If the answer is NO to all of the above questions they can proceed to make/attend an appointment.

If the answer is YES to any of the above questions the individual should be asked if they have any of the following symptoms - fever, cough, shortness of breath or any other features of an upper respiratory tract infection such as nasal discharge or frequent sneezing.

  • If the individual has any of the above symptoms then they should not make an appointment and should be advised about local authority guidelines.
  • If the individual does not have any of the above symptoms, it is acceptable for them to make an appointment BUT they should be advised to follow local guidelines for people who may be at risk of transmission (which may include quarantine).


- On attending clinic

Patients with respiratory symptoms and relevant travel history may also be identified when they book in at reception, for example by direct questioning or by incorporating a question on symptoms of cold or flu-like illness and travel in registration paperwork.

Ask the patient about:

  1. Recent travel to places with presumed ongoing community transmission of COVID-19.
  2. Recent contact with anyone with confirmed COVID-19.
  3. Recent work in or visits to a healthcare facility where patients with confirmed COVID-19 were being treated.
  4. If they have any of the following symptoms - fever, cough, shortness of breath or any other features of an upper respiratory tract infection such as nasal discharge or frequent sneezing.

If concerns about possible COVID-19 are identified in the course of a consultation:

  1. Isolate the patient away from other patients. Ideally, this should be an unoccupied room with the door closed. If a room is not available the person should be asked to wait in their car or be seated in an area separated by at least 6 feet or 2 meters from other individuals.
  2. Initiate basic protective procedures and use personal protective equipment (PPE: gowns, gloves, medical mask and eye protection)[8].
  3. Provide the patient with tissues, a surgical face mask and alcohol hand rub.
  4. Follow local authority guidelines to arrange a COVID-19 assessment.
  5. If the patient is to return home, they should quarantine themselves while awaiting home assessment. Patients should not travel home by taxi, public transport or walking. The patient may travel home by car if the patient feels well enough to drive or can be driven by a person who has already had significant exposure, who is aware of the risks and who is willing to drive them.
  6. Follow clinic cleaning and disinfection protocols once the patient has left the clinic.


A study by Rodrigo Pegado et al. describes key information on clinical characteristics, general care, and the role of physical therapists in preventing and promoting health and helping to contain the virus spread in Brazil[9].

Provide Education[edit | edit source]

Physiotherapists have a responsibility to share knowledge on preventing transmission of COVID-19. This should be done at any patient interaction - be it in the clinic, on the phone or via digital consultation.

In addition to this, many people will face weeks of isolation in quarantine and promoting health at these times will be key. Physiotherapists are well-placed to provide and should be proactive in offering health maintenance strategies including:

  • Activity - taking into consideration each particular individual's personal situation and health condition, provide advice on how to participate in appropriate activity.
  • Nutrition - good nutrition is key to boosting immunity.
  • Sleep - again, sleep is key to maintaining a strong immune system. People should be advised to engage in normal sleep patterns and good sleep hygiene.
  • Mind - the longer people are isolated, the more mental health will suffer, particularly for people living on their own. Be sure to offer strategies for good mental health by advising people to keep mentally active with learning and playing and maintain social relationships using online video conferencing tools such as WhatsApp and FaceTime.

Community (Home) Care[edit | edit source]

In the situation where a person has suspected COVID-19 with mild symptoms, care can be provided at home. It is suggested that a healthcare professional assesses whether the residential area is suitable for providing the necessary care. This might be particularly relevant when the person has co-morbidities, reduced functioning, disabilities and/or is elderly. The WHO has provided advice for providing home care for a case with mild symptoms[10].

Factors to Consider[edit | edit source]

  • Will the patient and family be able to adhere to the recommended precautions as part of home care isolation (adhere to hand and respiratory hygiene principles, cleaning of the home environment, limitation of movement around the home).
  • Will the patient and family be able to correctly handle safety concerns that arise while isolating at home (accidental ingestion or fire hazards that may be associated with the use of alcohol-based hand sanitisers).
  • A communication link between the patient, the healthcare professional and the public health authority of a specific area/country should be confirmed.
  • Education of the patient and family members of basic hand and respiratory hygiene principles.
  • Provision of ongoing support to the patient and family.

Recommendations for Patients, Families and Caregivers[edit | edit source]

  • Patients should remain in a well-ventilated room (open windows and doors).
  • Limit movement of patients around the home and limit shared spaces.
  • Shared spaces should be well-ventilated at all times.
  • Family or household members should stay in different rooms and keep a distance of at least 1m from the ill family/household member.
  • Limit the number of caregivers and no visitors allowed until the patient has recovered and has no more signs and symptoms.
  • Proper hand hygiene is essential after any contact with the patient or their immediate environment.
  • The patient should wear a medical mask to contain respiratory secretions.
  • Respiratory hygiene should be practised - cover mouth or nose with a disposable paper tissue when coughing or sneezing and dispose of appropriately. When tissue isn't available, sneeze or cough into the bend of the elbow and not into hands.
  • Caregivers are advised to wear medical masks when providing care to the patient.
  • Avoid direct contact with bodily fluids.
  • The patient should use dedicated linen and eating utensils - these should be cleaned with soap and water after use.
  • Surfaces in the patient’s room or areas where the patient resides should be cleaned and disinfected. It is recommended to use regular household cleaning products first and then a household disinfectant afterwards.
  • Bathroom and toilet surfaces should be cleaned at least once daily.
  • The patients’ clothes and linen may be washed with regular laundry products and water. Machine wash at temperatures of 60 - 90 ℃.
  • All gloves and masks used during home care isolation should be disposed of as infectious waste.
  • Avoid any exposure to contaminated items used by the patient (toothbrushes, towels, linen, wash clothes, eating utensils, etc).
  • Healthcare professionals tending to patients under home care should be familiar with and be able to select, use, remove and dispose of the correct personal protective equipment (PPE) to be used[11].

[12]

Acute (Hospital) Care[edit | edit source]

A minority group of people will present with more severe symptoms of COVID-19 and will need to be hospitalised, most often with pneumonia. In some instances, the illness includes severe pneumonia, ARDS, sepsis and septic shock[13]. In these cases, the physiotherapist may find themselves involved in the respiratory care of the patient.

Safety First[edit | edit source]

Specific advice for front line clinicians:

  1. Ensure that there are enough supplies and access to appropriate Personal Protective Equipment (PPE) for front line staff.
  2. Ensure that staff have an opportunity to take adequate breaks during and between shifts.
  3. Ensure access to appropriate support services for the psychological health of staff.

As with any contagious respiratory condition, care must be taken to protect yourself and those in the immediate environment by following strict protocols and ensuring the use of PPE as well as taking the following steps[14]:

  • Where possible treat the patient in a single room with the door closed.
  • Limit the number of staff present.
  • Minimise entry and exit from the room during treatment.

Respiratory Interventions[edit | edit source]

As with any patient displaying respiratory symptoms, it may be necessary to provide treatment to relieve symptoms and improve function. The secretion load of people with COVID-19 is low so they don't usually require invasive or intensive airway clearance techniques[15]. Physiotherapy support is more focused on non-invasive ventilation support measures, followed by the rehabilitation phase[15].

  • In the mild and moderate stages of disease, normal oxygen supportive measures (facemask oxygen) may be advantageous.
  • Patients with severe pneumonia often need oxygenation support. High flow nasal oxygen** is recommended at this stage, in conjunction with negative pressure room (if available)[16]. Nebulisation is not recommended[16].
  • Some patients may go on to develop ARDS. Noninvasive ventilation (NIV) is not routinely recommended[16] and these patients usually warrant intubation with mechanical ventilation. Prone positioning may assist ventilation and closed suctioning is recommended[16]. Extracorporeal membrane oxygenation may be indicated in patients with refractory hypoxia.


During the acute phase of COVID 19, Lazerri et al suggest any interventions that could potentially increase the risk of breathing are contraindicated and should be avoided[17]. Once stable and no longer acute, if indicated, the main goal in respiratory physiotherapy is to mobilise secretions and ease the work of breathing. Interventions may include techniques such as positioning, autogenic drainage, deep breathing exercises, breath stacking, active cycle of breathing, mobilisation and manual techniques (e.g. percussion, vibrations, assisted cough) to aid sputum expectoration**[18][19][20][14]. These interventions can be performed at any stage of the disease where appropriate and safe to perform.

**Particular attention should be given during those interventions that place the health staff at greater risk of contamination for aerial dispersion of droplets, such as sputum induction, open suctioning, nebulisers, high flow oxygen, NIV, as these are a potential route for transmission for the virus[21]. Airborne PPE must be used.

This section on respiratory interventions is a summary, please read the Respiratory Management of COVID-19 for more specific information.

Management of Contacts[edit | edit source]

According to the WHO, any person (including healthcare workers) who has been exposed to an individual with suspected COVID-19 is considered a "contact". These contacts are advised to monitor their health for 14 days from the last day of possible contact in order to take appropriate action if necessary.[10]

The WHO[22] describes a contact as a person who is involved in any of the following from 2 days before and up to 10 days after the onset of symptoms in the patient:

  • Providing direct care for patients with COVID-19 disease without using proper personal protective equipment.
  • Staying in the same close environment as a COVID-19 patient (including sharing a workplace, classroom or household or being at the same gathering).
  • Travelling in close proximity with (that is, having less than 1 m separation from) a COVID-19 patient in any kind of conveyance.

The following counts as exposure to contacts:

  • Healthcare-related contact - providing direct care to patients with COVID-19.
  • Working in close proximity or sharing a classroom with a person with COVID-19.
  • Travelling with a person(s) with COVID-19 in any kind of vehicle.
  • Living in the same household as a person with COVID-19 within 14 days after the onset of the person’s symptoms.

Healthcare professionals should monitor their contacts on a regular basis. Recommendations if a contact develops symptoms[10]:

  • Notify the relevant healthcare authorities as well as the medical facility where symptomatic contact will be directed to.
  • Symptomatic contact should wear a medical mask while travelling to seek care.
  • The symptomatic contact should avoid taking public transport if possible - an ambulance can be dispatched or if the person is being transported via private vehicle, all the windows should be opened (vehicle well-ventilated).
  • The symptomatic contact should be advised on proper hand and respiratory hygiene as well as to keep a distance of at least 1 m from others.
  • Clean and disinfect any surfaces that could have been contaminated with respiratory secretions during transport of the symptomatic contact with cleaning products and then with a disinfectant.

This article describes the guidelines on specific aspects of physiotherapy of patients with COVID-19 to limit the spread of the disease and secure the safety of health care personnel[23].

Workforce Planning[edit | edit source]

Physiotherapists may find themselves in a position to reduce the workload in emergency departments and/or divert staff to contribute to the care of hospitalised COVID-19 cases. The key to workforce planning is to identify what the unique contribution is of your clinic and/or staff, and what your generic contribution is to pandemic planning:

  • Respiratory and on-call teams can be mobilised to the intensive care units and medical wards.
  • Musculoskeletal physiotherapists can contribute in the rehabilitation phase to assist recovered COVID-19 cases return to full function.
  • Outpatient departments in hospitals could assist with acute/urgent injury cases that present to emergency departments to keep them out of the contagious environments, such as keeping them out of COVID-19 screening queues.
  • Service providers can set up telemedicine services to keep people socially distanced and out of contagious environments.

Protecting Staff[edit | edit source]

It is important when planning services that physiotherapists who fall into the high-risk categories should avoid contact with Covid-19 patients. These include members of the team that[24]:

  • Are pregnant - while at present the risks from COVID-19 are unconfirmed, it is known that exposure to any respiratory disease carries an increased risk of complications for mother and baby.
  • Have a known chronic respiratory illness.
  • Are immunosuppressed or have immune deficiencies.
  • Are over the age of 60 years.
  • Have an underlying health condition such as heart disease, lung disease or diabetes.
  • Have immune deficiencies, such as neutropenia, disseminated malignancy and conditions or treatments that produce immunodeficiency [12].

Telemedicine Consultations[edit | edit source]

To reduce transmission or in the case where a clinic is forced to close, you may consider implementing digital strategies to continue the delivery of your service. There are currently no established or recognised global standards or agreement for delivering physiotherapy care digitally. However, the overall emerging evidence appears to indicate that digital technologies are providing new opportunities for the physical therapy profession to deliver high-quality and acceptable care to users of their service in ways that can have benefits for all[25]. Some national physiotherapy organisations are welcoming the use of digital practices where it enhances the service to the patient[26]. To implement telemedicine a variety of approaches can be used such as the use of general communication tools such as email, chat/messaging, and video conferencing and/or physiotherapy specific platforms such as online exercise prescription tools. It is important to take into account the barriers to access the use of these tools may present for some patients and provide support where required if possible[27]. Review and follow all national or state laws (practice acts/legislations) regarding telemedicine or telehealth services.

[28]

Rehabilitation After COVID-19[edit | edit source]

Rehabilitation in the recovery phase is going to be a key responsibility of physiotherapists in collaboration with the multidisciplinary team, including occupational therapists, speech and language therapists, dieticians and psychologists.

Resources[edit | edit source]

References[edit | edit source]

  1. Thomas P, Baldwin C, Bissett B, Boden I, Gosselink R, Granger CL et al. Physiotherapy management for COVID-19 in the acute hospital setting: clinical practice recommendations. J Physiother. 2020;66(2):73-82.
  2. APTA Statement on Patient Care and Practice Management During COVID-19 Outbreak. 17 March 2020 http://www.apta.org/Coronavirus/Statement/ Accessed 18 March 2020.
  3. MacIntyre CR, Wang Q. Physical distancing, face masks, and eye protection for prevention of COVID-19 [published correction appears in Lancet. 2020 Jun 5;:]. Lancet. 2020;395(10242):1950-1.
  4. Smith AC, Thomas E,  Snoswell CL, Haydon H, Mehrotra A, Clemensen J et al. Telehealth for global emergencies: Implications for coronavirus disease 2019 (COVID-19). Journal of Telemedicine and Telecare. 2020;26(5):309-13.
  5. World Health Organization. Medical and fabric masks: who wears what when? Available from https://www.youtube.com/watch?time_continue=45&v=esM_ePHn0aw&feature=emb_logo [last accessed 7/8/2020]
  6. WHO. Q&A on coronaviruses (COVID-19). 9 March 2020
  7. CDC. Coronavirus Disease 2019 (COVID-19). How to Protect Yourself
  8. World Health Organisation. Advice on the use of masks in the community, during home care and in health care settings in the context of the novel coronavirus (2019-nCoV) outbreak. https://www.who.int/publications-detail/advice-on-the-use-of-masks-in-the-community-during-home-care-and-in-healthcare-settings-in-the-context-of-the-novel-coronavirus-(2019-ncov)-outbreak Accessed 14 March 2020
  9. Pegado R, Silva-Filho E, Lima IN, Gualdi L. Coronavirus disease 2019 (COVID-19) in Brasil: information to physical therapists. Revista da Associação Médica Brasileira. 2020 Apr;66(4):498-501.
  10. 10.0 10.1 10.2 World Health Organisation. Home care for patients with suspected novel coronavirus (nCoV) infection presenting with mild symptoms and management of contacts. https://www.who.int/publications-detail/home-care-for-patients-with-suspected-novel-coronavirus-(ncov)-infection-presenting-with-mild-symptoms-and-management-of-contacts Accessed 14 March 2020
  11. World Health Organisation. Rational use of personal protective equipment for coronavirus disease 2019 (COVID-19). https://apps.who.int/iris/bitstream/handle/10665/331215/WHO-2019-nCov-IPCPPE_use-2020.1-eng.pdf Accessed 14 March 2020
  12. Centers for Disease Control and Prevention (CDC). 10 Things You Can Do to Manage COVID-19 at Home. Published on 7 August 2021. Available from https://www.youtube.com/watch?v=l6775rnLdAk. [last accessed 31 May 2022]
  13. World Health Organisation. Clinical management of severe acute respiratory infection (SARI) when COVID-19 disease is suspected. 13 March 2020. https://www.who.int/docs/default-source/coronaviruse/clinical-management-of-novel-cov.pdf. Accessed 18 March 2020.
  14. 14.0 14.1 Rachael Moses. COVID 19: Respiratory Physiotherapy On-Call Information and Guidance. Lancashire Teaching Hospitals. Version 1 dated 12th March 2020
  15. 15.0 15.1 Rachael Moses. Physiotherapy Interventions for COVID-19. 18 March 2020. https://vimeo.com/398333258 Accessed 19 March 2020
  16. 16.0 16.1 16.2 16.3 Australian and New Zealand Intensive Care Society. ANZICS COVID-19 Guidelines. Melbourne: ANZICS  2020
  17. Lazzeri M, Lanza A, Bellini R, Bellofiore A, Cecchetto S, Colombo A, D'Abrosca F, Del Monaco C, Gaudellio G, Paneroni M, Privitera E. Respiratory physiotherapy in patients with COVID-19 infection in acute setting: a Position Paper of the Italian Association of Respiratory Physiotherapists (ARIR). Monaldi Archives for Chest Disease. 2020 Mar 26;90(1).
  18. David A. Autogenic Drainage - the German approach. In: J. Pryor, editor. Respiratory Care, Edinburgh: Churchill Livingstone; 1991
  19. Pryor JA. Physiotherapy for airway clearance in adults. European Respiratory Journal.1999;14: 1418-1424
  20. Chatwin M, Ross E, Hart N, Nickol AH, Polkey MI, Simonds AK. Cough augmentation with mechanical insufflation/exsufflation in patients with neuromuscular weakness. Eur Respir J. 2003;21:502-508.
  21. Respiratory physiotherapy in patients with COVID-19 infection in acute setting: a Position Paper of the Italian Association of Respiratory Physiotherapists
  22. World Health Organisation. Global Surveillance for human infection with coronavirus disease (COVID-19). https://www.who.int/publications-detail/global-surveillance-for-human-infection-with-novel-coronavirus-(2019-ncov) Accessed 14 March 2020
  23. Review . 2020 Jun 22;75:e2017. doi: 10.6061/clinics/2020/e2017. eCollection 2020. Physiotherapy Care of Patients with Coronavirus Disease 2019 (COVID-19) - A Brazilian Experience. Clinics (Sao Paulo)
  24. Thomas P, Baldwin C, Bissett B, Boden I, Gosselink R, Granger CL, Hodgson C, Jones AYM, Kho ME, Moses R, Ntoumenopoulos G, Parry SM, Patman S, van der Lee L (2020): Physiotherapy management for COVID-19 in the acute hospital setting. Recommendations to guide clinical practice. Version 1.0, published 23 March 2020
  25. WCPT and INpTRA. Report of the WCPT/INPTRA Digital Physical Therapy Practice Task Force. May 2019. http://www.inptra.org/portals/0/pdfs/ReportOfTheWCPTINPTRA_DigitalPhysicalTherapyPractice_TaskForce.pdf Accessed online 14 March 2020
  26. Irish Society of Chartered Physiotherapists. POLICY and GUIDELINES on e-HEALTH for Physiotherapists in Private Practice. March 2020. iscp.ie/sites/default/files/documents/ISCP%20E%20Health%20Guidelines%20March%202020.pdf. Accessed online 14 March 2020
  27. Scott Kruse C, Karem P, Shifflett K, Vegi L, Ravi K, Brooks M. Evaluating barriers to adopting telemedicine worldwide: A systematic review. Journal of telemedicine and telecare. 2018 Jan;24(1):4-12.
  28. Phzio Telehealth. COVID-19 Phzio Virtual Care Treatment. Published on 13 March 2020. Available from https://youtu.be/UMnh2WdkvdA. [last accessed 18 March 2020]