Review of Respiratory Medicine - Volumen 22, Número 3 - September 2022

Special Article

Respiratory Rehabilitation in Patients with SARS-COV-2. Current State of Knowledge

Rehabilitación respiratoria en pacientes con SARS-COV-2. Estado de conocimiento actual

Received: 09/16/2021

Aceptado: 03/27/2022

INTRODUCTION RATIONALE AND JUSTIFICATION OF THE DOCUMENT

In December 2019, the first case of the disease caused by the SARS-Cov-2 virus was detected in the city of Wuhan, China.¹ Unlike the limited character of the two previous epidemics, the Middle East Respiratory Syndrome (MERS) and the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), the rapid expansion of SARS-CoV-2 forced the World Health Organization (WHO) to declare the pandemic in March, 2020.²

According to the reports on the evolution of the pandemic available at the John Hopkins University (JHU), at the time this document was written, around 160 million cases and 3.3 million deaths had been reported.³ During the first year, the pandemic caused 1.8 million deaths around the world, compared to 2.6 million deaths produced by all the lower respiratory tract infections in 2019.⁴

The mortality produced by all the respiratory in­fections in 2017 (last available record) was 64,869 deaths, and the mortality produced by SARS-CoV-2 only within one year of the pandemic accounted for 53,741 deaths.^5,6

Apart from the mortality produced by SARS-CoV-2, we must consider two other levels of impact: the first one, generated by the acute disease, re­quires the early intervention of the rehabilitation tool, such as in the ICU (Intensive Care Unit) and in-patient wards. The second level of impact refers to the chronic disease, the multiple physical, psy­chological and neurocognitive functional sequelae that are usually expressed as Post-Intensive Care Syndrome (PICS) in critically ill patients.

A national study conducted on a sample of 207,000 patients with complete data, treated be­tween March and October 2020, allows us to have an approximate estimation of how many patients who suffered from the disease caused by SARS-CoV-2 required rehabilitation.⁷ 20.1% of them (41,703 patients) were hospitalized, out of which 2.7% (5,652 patients) were admitted to the ICU. Only among these ICU survivors (around 2,800 patients), then in the intermediate care ward, and finally with the outpatient in-person or remote modality, would rehabilitation be justified in that context.

Apart from the patients admitted to the ICU, the indication should also include patients with mod­erate or severe forms of the disease who required different levels of oxygen therapy in intermediate care or general wards.

In view of the above, an early intervention is urgently needed, mainly in the respiratory, cardio­vascular, neuromotor, cognitive and psychological areas, in order to minimize sequelae and try to reach maximum patient’s autonomy and the best possible quality of life.⁸

In any case, the most important thing is that rehabilitation becomes a continuous intervention. We recommend to keep a common line of work throughout the different stages of disease evolu­tion. This applies to both patients who begin this intervention in the ICU, continue in the general ward and then during the outpatient period, and to those who begin in the general ward and continue on an outpatient basis.

The objective of this document is to offer the professionals involved in the respiratory rehabili­tation of these patients a set of recommendations supported by the current state of knowledge and endorsed by our specialized experts that can be feasibly used in centers of different complexity levels in our country.

CLINICAL PRESENTATION OF INFECTION BY SARS-CoV-2

Infection by SARS-CoV-2 can be symptomatic or asymptomatic. Symptomatic patients may show mild and moderate or even severe forms of the dis­ease with pneumonia and ARDS (acute respiratory distress syndrome), with respiratory failure and multi-organ failure. Also, long-term complications could occur after SARS-CoV-2 infection, causing the post-COVID syndrome (pCS) or the persistent COVID syndrome (PC).

Around 80% of patients with COVID-19 develop mild to moderate disease; 15% progress to severe stages and require oxygen support, and 5% develop a critical disease including ARDS, septic shock and multi-organ failure.⁹ Age and various comorbidities such as diabetes, obesity, lung and cardiovascular diseases and some genetic polymorphisms cor­relate with a higher risk of respiratory failure.^10-12

We must also take into account that approxi­mately 50% of people with severe pneumonia caused by COVID-19 develop ARDS, with pulmo­nary fibrosis as a common complication.¹³ These patients will have damaged lung function with irreversible respiratory failure associated with bad prognosis.¹⁴

A. RESPIRATORY REHABILITATION IN COVID-19 PATIENTS ADMITTED TO THE CRITICAL CARE UNITS

Patients with COVID-19 whose treatment requires hospitalization in the Intensive Care Unit (ICU) with or without invasive mechanical ventilation (IMV) need early kinesiology care, not only for the management of the ventilatory treatment, but also for the motor rehabilitation that is necessary for the patient to go back to his/her regular activities after discharge.

In this section we suggest that general guide­lines are established regarding the way in which we should evaluate the impact of rehabilitation upon these patients, which tests can be done, and how to address the rehabilitation process of COVID-19 patients in the ICU.

The first thing to decide is how the rehabilitation plan should be organized, taking into account that it has to be individualized and customized. In order to do that, several aspects are to be considered:

1. Setting suitable titration of analgesia and seda­tion, depending on the ventilatory mode that is being used, disease evolution, and the patient’s oxygenation state.

2. Using a ventilator mode and setting that are adequate for the patient (avoid the patient/ ventilator asynchrony), on distension and hy­poventilation.¹⁵

3. Providing the kinesiology treatment gradually, taking into account the clinical status of the patient.

4. Monitoring with strict safety criteria.¹⁶

5. Planning early rehabilitation together with the interdisciplinary team.

When addressing the important aspects de­scribed in this section, we use four trigger ques­tions for educational purposes.

1. Which are the objectives of a rehabilitation process in the ICU?

The main objective of an early rehabilitation pro­gram (ER) (defining the ER as an intervention to provide motor, sensitive and proprioceptive stimuli that generate in the patient a less negative impact of the ICU admission), is to avoid losing the func­tionality the patient had before being admitted to the critical care area.¹⁷

Also, the objectives related to the ER must be proposed, for example, reducing sedation and an­algesia, maintaining the range of motion, sitting position, standing position and walking. Then come the DLAs (daily living activities).

These goals have to be proposed upon the pa­tient’s admission to the critical care area, and must be evaluated upon discharge.

For the correct organization of the proposed objectives, the measures known as the “ABCDEF Bundle” can be used, especially when there is early weaning, prevention and treatment of delirium and early rehabilitation.¹⁸ This allows for the co­ordination of patient care in order to wean him/ her from IMV and discharge him/her from the ICU.

2. Which are the necessary criteria to begin rehabilitation?

The kinesiologist has to adapt to the patient’s con­ditions: whether he/she has orotracheal intubation or tracheotomy, invasive or non-invasive mechani­cal ventilation, humidified high-flow therapy or any other form of oxygen therapy support. It is essential to consider the presence of drug admin­istration routes, drainage, hemodynamic stability and monitoring.

The patient must have a stable medical condi­tion, one airway free of complications and ensured oxygen requirement, and he/she should also begin the respiratory rehabilitation (RR) session, ensur­ing the use of drugs if necessary.

The criteria are defined in the following way:¹⁹

1. Heart rate of less than 50% of the theoretical maximum heart rate (TMHR).

2. Blood pressure with a variability of less than 20% (avoid hemodynamic decompensation).

3. Normal electrocardiogram.

4. Partial oxygen saturation > 90% with a reduc­tion of less than 4 points at the time of the ER.

5. PaO2/FiO2 > 300 (ER tolerance index with good reserve volume; lower values reduce such vol­ume, state of alert).

6. Adapted respiratory pattern.

7. Stable mechanical ventilation.

8. Stable airway.

9. Absence of fever.

3. How is the patient who begins rehabilitation in the ICU evaluated?

The evaluation must include respiratory and mus­cular functions and state of consciousness. The recommended instruments are:

1. Evaluation of dyspnea through the mMRC (Modified Medical Research Council) scale.²⁰

2. Evaluation of the muscular state through the MRC scale.²¹

3. Assessment of sedation and analgesia and pa­tient’s state of alert: Visual Analog Scale (VAS), Pain Behavior Scale (PBS) Richmond Agitation- Sedation Scale (RASS), and delirium scale (CAM-ICU, Confusion Assessment Method for the Intensive Care Unit).^22-24

4. Which are the elements of the ICU’s early rehabilitation plan?

Stages must be respected according to the Morris model of complexity levels²⁵.

The plan consists of the following steps:

• Including two daily stimuli from the patient’s admission to the critical care area until dis­charge.

• The initial level (deeply sedated patient) in­cludes passive movement of the limbs and postural control.

• Once the patient regains consciousness, he/ she begins with active-assisted exercises and functional progression as he/she meets the objectives. Such progression includes: sitting on the corner of the bed, trying the standing position once he/she controls his/her trunk, and then walking around with assistance and doing activities outside the bed. 25,26

• Including family members in the rehabilita­tion process through videocalls and helping the patient both with functional progression and providing the patient’s elements (watch, glasses, books, radio, etc.)

• Recording adverse events so as to avoid repeat­ing them.

B. RESPIRATORY REHABILITATION ON THE IN-PATIENT WARD

As we already mentioned, it is estimated that between 14% and 20% of patients infected with SARS-CoV-2 will require hospitalization in a gen­eral in-patient ward, so complications associated with immobilization could generate a negative impact on the patient’s quality of life.^7,27 Thus, it is essential that the patient receives respiratory rehabilitation treatment during hospitalization, for the prevention and timely management of physical deconditioning effects and effects related to the appearance of sequelae.²⁸

When the patient is transferred from the ICU to Intermediate Care or to the in-patient ward, the RR has to be continuous and in-line with the treatment that had already begun in the ICU; in the case of patients initially admitted to the in-patient ward, they have to meet the following conditions once they are included in the rehabili­tation program:

1. Patients coming from the ICU, will continue with their RR treatment but those who are directly admitted to the in-patient ward have to establish their corresponding treatment.

2. An evaluation will be carried out to identify prognostic factors of PICS syndrome, chronic damage caused by COVID, post-COVID syn­drome and persistent COVID syndrome, in patients coming from the ICU.²⁹

3. Rehabilitation goals have to be set.^27,30

4. Patient’s evolution has to be monitored.

5. The comparison between the RR parameters and applications in its different stages is recom­mended.

Three triggering questions are included in this section that intend to address to whom, how and when to perform the RR in a general in-patient ward.

1. Which are the conditions for COVID-19 patients to begin RR on the in-patient ward?

According to the aforementioned, around 3-5% of moderately ill patients will develop severe or even critical disease 7 to 14 days after the onset of the infection^31,32.

The parameters that should be evaluated in patients coming from the ICU are: ^31-33

1. Time since the onset of symptoms.

2. Type and number of symptoms.

3. Oxygen saturation values.

4. Intensity and extent of pulmonary involvement.

5. Supplemental oxygen requirement and types of administration.

6. Need to use invasive or non-invasive mechanical ventilation.

7. Ventilation time and possible complications.

8. Coexistence of renal, hematologic, neurologic or any other type of complication and type of treatment received.

9. In patients directly admitted to the in-patient ward, an observational behavior must be set, depending on the patient’s evolution.

A. EXCLUSION AND TERMINATION OF EXERCISE CRITERIA

A.1 EXCLUSION CRITERIA^27,31

– Patient with fever.

– Time of initial consultation ≤ 7 days in patients directly admitted to the in-patient ward.

– Duration of the disease ≤ 3 days from onset to appearance of dyspnea, due to disease progres­sion or fully active clinical condition.

– Progression of opacities in chest X-ray of at least 50% in 24 to 48 hours.

– SO2 ≤ 90% with supplemental oxygen.

– Heart rate < 40 or > 130 bpm.

– Blood pressure at rest < 90/60 or > 140/90 mmHg.

– Respiratory rate > 24 bpm.

– Lack of consent from the patient.

A.2 TERMINATION OF EXERCISE CRITERIA ^27,31,33

– Modified Borg Scale value > 3 for dyspnea score at the initial stage of RR.

– Drop in SpO2 > 4%.

– Signs of chest tightness.

– Alterations in ventilatory mechanics and/or use of accessory muscles.

– Breathing difficulty, dizziness, headache, blurry vision, palpitations, excessive sweating and bal­ance disorder.

– Other conditions determined by the physician as inadequate for doing the exercise.

2. How should patients included in the rehabilitation intervention be evaluated?

The different evaluations described below shall be selected depending on the working context of each professional.

There are different fields within the scope of the evaluation:

1. EVALUATION OF THE PATIENT’S GENERAL CONDITION

It will observe the breathing rhythm, the state of muscular masses, mobility and range of motion, state of consciousness and the possibility to cooper­ate in the rehabilitation.

2. EVALUATION OF DYSPNEA

In order to evaluate the level of dyspnea, many validated, simple scales can be used.

2.1 Modified Borg Scale: to evaluate the level of effort perceived by the patient and to be able to prescribe and control the intensity of the activity²⁷.

2.2 Visual Analog Scale ³⁴

3. EVALUATION OF EXERCISE CAPACITY

If allowed by the respiratory, cardiac and metabolic reserves of the patient, the following tests can be done:

3.1 1- MIN SIT-TO-STAND TEST (STS1’): this test will allow the evaluation of desaturation induced by exercise.³⁵

3.2 5R-STS: normal cut-off point ≤ 12 sec­onds.³⁶

3.3 TEST TIME UP and Go (TUG): abnormal cut-off point for fall risk shall be ≥ 16 seconds.³⁷

3.4 4 - METRE GAIT SPEED: this test will evaluate the time needed to walk 4 meters at a normal speed. A value > 0.8 m/sec shall be con­sidered abnormal.³⁸

4. STRENGTH ASSESSMENT

3.1 Medical Research Council Scale (MRC)²⁷ .

3.2 Repetition method.^39-41

4 EVALUATION OF DAILY LIFE ACTIVITIES (DLAS)

4.1 PCFS²⁹

4.2 Barthel Index⁴²

4.3 Katz Index⁴³

3. When and how should these patients undergo the peripheral muscle training?

We suggest early rehabilitation in patients com­ing from the ICU and in those who are directly admitted to the in-patient ward during the first 3 days after the patient was stabilized. It is also important to have good pain control, in order to favor the achievement of objectives.²⁷

The design of RR programs for patients with COVID-19 must respect the general principles of training, which are related to intensity, duration, frequency, specificity and exercise reversibility.^30,44

To do that, the training objectives and scope have to be planned with each patient, taking into account their exercise capacity tests. ⁴⁵.

PATIENT MONITORING: patients should be monitored before, during and after the rehabilita­tion session. Variables to monitor are:

0.1 SpO2: it has to be higher than 90% with supple­mental oxygen, with less than 4% variability tolerance during the session.²⁷

0.2 Blood pressure: no more than 20% variability tolerance during the session.⁴⁶

0.3 HR: no more than 80% variability tolerance of the TMHR is suggested²² .

0.4 Respiratory rate: it shouldn’t be higher than 24 bpm.⁴⁶

0.5 If possible, the session must be restarted once the already mentioned parameters go back to normal.²⁷

1. MUSCULAR STRENGTH TRAINING:

1.1 It is suggested that patients begin with big muscle groups (shoulder girdle and pelvic girdle).⁴³

1.2 Then, balance, proprioceptive and coordina­tion exercises will be included. Fall risks will be monitored.²⁷

1.3 Exercise intensity: patients will begin with ac­tive mobility exercises, and continue with sets of low intensity exercises using the body-weight (60% of the maximum intensity achieved with the repetition method), and then will continue to increase intensity according to the muscular response of each patient. 3 sets per muscular group with a pause of 2 minutes between each set are suggested.^47,48

1.4 Functional training is recommended.^49-51

1.5 A frequency of two times a day is suggested.²⁷

1.6 Regarding the duration of the session, it is recommended that the patient begins with 20 minutes and progresses to 30 minutes per session.

2. AEROBIC CAPACITY TRAINING

2.1 Given the small size of the rooms in the in-patient ward, exercises should be done with short displacement, also taking into account epidemiologic safety.

2.2 The intensity of exercise must be progressive until the patient reaches 80% of the TMHR.

2.3 Training methods can be continuous or inter­mittent.²⁷

2.4 A frequency of two times a day is recom­mended.²⁷

2.5 The duration of the session shall preferably be 20 minutes, minimum, and must progress to 30 minutes.

RESPIRATORY REHABILITATION AFTER HOSPITAL DISCHARGE

It is extremely important that before hospital dis­charge, a report is made describing the most urgent needs of the patient, such as the safety of home mobility, symptom control, supplemental oxygen requirement, suitable nutrition, psychological and social support, and short- and long-term needs, for example, improvement in physical and emotional functions and return to work.¹⁷

C. RESPIRATORY REHABILITATION IN OUTPATIENTS WITH POST-COVID-19 SYNDROME AND LONG OR PERSISTENT COVID SYNDROME

This section has the purpose of addressing re­spiratory rehabilitation in patients who suffered from the disease caused by SARS-Cov-2 and were discharged from hospital, as well as those who were treated on an outpatient basis but evolved and still have dyspnea.

This chapter uses five trigger questions about issues of interest to the professionals in charge of the Respiratory Rehabilitation Programs (RRPs) in outpatient modality.

1. What do post-COVID-19 syndrome and long or persistent COVID syndrome mean?

In accordance with different international studies, the duration of the symptoms caused by COVID-19 infection has a mean value of 11 days for patients who weren’t hospitalized and 13 to 25 days for those who required hospitalization⁵² . However, after the resolution of the viral infection, it has been observed that some signs and symptoms tend to prolong. The post-COVID-19 syndrome (here­inafter referred to as pCS) is defined as the group of signs and symptoms that appear after the acute infection has been resolved.^53-61 It includes persis­tent symptoms that could be related to residual inflammation (in the convalescent phase), organic damage, non-specific effects of hospitalization or prolonged ventilation (PICS) and long or persistent COVID (PS).^52-53

The first description alerting us to the impor­tance of the pCS appeared in a patient survey conducted in the United States between April and May, 2020⁵⁴. The name “pCS” came from that work and was endorsed by Greenhalgh in a subsequent publication.⁵⁵

Spanish authors propose considering four stages of the SARS-CoV-2 disease and defining those clinical conditions depending on evolution.⁵⁶ Thus, symptoms related to the acute infection would be limited to the first 4 weeks; acute pCS would describe symptom persistence for 5-12 weeks; pro­longed symptoms would be divided in two groups: long post-COVID syndrome (LS), of 12-24 weeks of evolution and persistent syndrome (PS), prolong­ing beyond 24 weeks from the onset of symptoms.⁵⁶

However, there isn’t any universally accepted name in the definitions of pCS and PS. Two Span­ish guides define the pCS as the group of systemic findings beyond 4 weeks from the onset of the first symptom, with the signs and symptoms being part of the acute infection as essential require­ment.^52-53 The NICE Guide (National Institute for Health and Care Excellence) from the United Kingdom takes the PS into consideration after 12 weeks, and the WHO Guide, as of the fourth or fifth week.^57,58

The frequency of the PS is of approximately 10-35% of patients in general, even though in critically ill, hospitalized patients it can reach 80%.^53,54,59

2. How to differentiate the pCS and PS from other similar clinical conditions?

It is important to differentiate the post-COVID symptoms from other situations that can be simi­lar but don’t share their temporal pattern and/or clinical presentation.

A. In cases in which signs and symptoms are present before the onset of COVID-19 clinical conditions.

B. If signs and symptoms appear after the infection and weren’t a part of it (post-viral symptoms).

C. If signs and symptoms appear after the infection and weren’t a part of the initial clinical condi­tion and were caused by the organic damage gen­erated by the infection (COVID-19 sequelae).^52-53 Unlike the PS, patients who have progressed with organic sequelae are usually older males with previous comorbidities that don’t evolve in an outbreak like the PS.⁵³

D. Finally, the situation arising from systemic or organic damage due to a severe infection (post- Covid-19 chronic damage)⁵²

3. Which is the presentation and clinical profile of the patient with PS who is referred to a Respiratory Rehabilitation Program?

López León et al conducted a systematic review and meta-analysis of the available literature on prolonged signs and symptoms caused by CO­VID-19 infection.60 6 of 15 studies belonged to hospitalized patients, and they had a follow-up of 14-110 days. 55 persistent signs or symptoms re­lated to the viral infection were identified, the most common being: fatigue (58%), headache (44%), attention disorders (27%), hair loss (25%), and dyspnea (24%). In 7 studies (n = 1,915 patients), 80% of the subjects had at least one persistent symptom.⁶⁰

Regarding the profile of the patient normally referred to RRPs with a diagnosis of PS, a survey of 3,762 patients from 56 countries described symp­toms up to 7 months after the onset of the acute infection.⁶² Most patients had at least 3 months of evolution, a mean of 14 symptoms per patient and an average of 9 affected organs⁶¹.

With respect to the degree of disability that is usually self-perceived by the patients, a Spanish survey shows that patients reported 50% disabil­ity.⁶² When describing each activity in detail, the most common limitations were found in personal hygiene and daily life activities, especially family duties and recreation activities.⁶²

4. When, where, and how can a patient with pCS and PS be initially evaluated?

Evidence regarding which is the best approach for patients with pCS and PS referred to the RRP is scarce.^{30,52,57,58,63-65,66-70} However, there are unani­mous criteria about several important issues.

First, in this work we believe that patients who have been hospitalized for a long time or had oxygen requirement or ventilatory support need outpatient or home respiratory rehabilitation as a continuous strategy following the treatment that started in the ICU or general ward.

Secondly, given the multiplicity of organs af­fected by the PS, the high number of symptoms reported by patients and their time of evolution, it is necessary to have a multidisciplinary approach for those who suffered from COVID-19 and arrive at the RRP.^{30,53,57,58,63-70}

In the third place, it’s clear that, as far as is practical, rehabilitation must focus on the pa­tient.^{30,53,57,63-70} This means that the place where the patient is to be evaluated will depend on his/ her needs and possibilities.

A. Remote evaluation of patients with pCS and PS

Even though there is agreement on the usefulness of telemedicine in certain groups that apply to the RRPs, at the moment there isn’t any standard­ized, validated protocol on how to evaluate and train patients with pCS and PS remotely. The consulted literature relies on experts’ recom­mendations.^{44,52,53,57,63,70} We must take into account three basic aspects when a patient is going to be included in a distance RRP: indication, accord­ing to the particular situation of the patient; the criteria that the patient has to meet in order to access the intervention on equal terms; the char­acteristics of the tools that are going to be used for the evaluation.^44,67-70

Table 1 describes the indications, inclusion cri­teria that ensure equality between patients and tools to be used in the process.

We recommend that the evaluation of these patients is standardized in steps.

The first step consists in evaluating the patient’s personal history and history of present illness, provided in the epicrisis of the hospitalization medical records.^{30,44,52,53,57,63,66,68-70} The information to be included is: preexistent comorbidities, history of present illness, for example, time of evolution of the condition and initial symptoms, days of hospital stay, extension and severity of the disease, type of oxygen therapy, if so required (used devices and flows), application, if any, of invasive and non-invasive ventilation (days of effective ventilation), administered treatment and patient’s response, laboratory anomalies of clinical and prognostic relevance and list of complications and potential sequelae registered after hospital discharge.^44,66,68,69

The importance of the number of initial symp­toms is related to a higher risk of suffering PS. The presence of five or more symptoms during the first week of evolution increases the risk of suffering from a prolonged disease by 3.53 times, compared to patients who show less than five symptoms.^{44,64,66,68,69}

The second step includes the remote estimation of the patient’s general condition: his/her aspect, the state of muscular masses, the ventilatory me­chanics, the identification of movement limitations and the state of consciousness⁶⁹

With the third step we are able to establish the patient’s level of dyspnea and exercise capacity.

The patient is asked to identify his/her level of dyspnea in accordance with the Borg dyspnea scale and the Modified Medical Research Council scale (mMRC).^67-70 In order to test if he/she needs oxygen, the patient is requested to measure oxy­gen saturation (SpO2) while sitting and at rest. If the values are ≥ 96%, the patient is asked to walk forty steps on a flat surface, with the oximeter. In the case of patients who don’t have an oximeter, or as supplementary information of those who do, we recommend exercises that don’t exceed 4 (four) points in the Borg Scale for perception of dyspnea.⁶⁹

Apart from estimating dyspnea and SpO2, the patient’s heart rate (HR) must be monitored, at rest and after each set of exercises. Since the activ­ity isn’t supervised, we suggest the formula of 220 beats minus the patient’s age.

A second alternative to evaluate exercise capac­ity is the remote Sit-to-Stand Test (STS). Although it has been developed and validated for patients with COPD, given its safety and simplicity, it has been proposed in publications on distance reha­bilitation.^69-71 From the less demanding modality of 5Rs, to the sit-to-stand in 30 sec (STS30”) and 1-min sit-to-stand test (STS1’), these tests allow the evaluation of concentric and eccentric contrac­tion of the quadriceps, the steady state and even the 1’ variant correlates with the 6-Minute Walk Test (6MWT).^65,71

The fourth step consists in evaluating muscle strength and nutritional status, commonly al­tered by the sarcopenia of pCS and PICS.^{30,44,52- 55,57,60,64,66,68-70}

We suggest the strength evaluation method in 8 MRs (maximum repetitions), the evaluation of 3-4 muscle groups of the upper and lower body and monitoring with the Visual Analog Scale of HR and SpO2. For the purpose of calculating the patient’s capacity to face daily activities, we propose evalu­ating the weights using the patient’s body weight.

With regard to the nutritional status, the Body Mass Index (BMI) is assessed and muscular masses are observed; that will allow us to have an approxi­mate idea on the nutritional status of the patient.⁶⁹ Also a virtual follow-up must be performed, and the nutritionist must provide the most suitable diet for the patient.

The fifth step consists in evaluating Daily Life Activities (DLAs).

In accordance with the idea of using the simplest objects for the evaluation, we suggest the use of the functional status index of patients with COVID, called Post-COVID Functional Status, at the time of hospital discharge and 4, 8 and 24 weeks after (PCFS).²⁹

The sixth step refers to the evaluation of the psychological sphere. There is a consensus on the use of the Hospital Anxiety and Depression Questionnaire (HAD), an instrument that has been validated for the Spanish language and suggested for virtual PS patients.^68,72,73

The following table describes the steps of the remote evaluation of COVID-19 patients.

B. In-person evaluation of patients with pCS and PS

The in-person evaluation of patients with pCS and PS shares the first steps with the remote evaluation, for example, the epicrisis informa­tion and general and particular observation of the patient.

With regard to the evaluation of dyspnea and exercise capacity, with this modality the patient can do the 6MWT or the Shuttle Test so as to cal­culate those variables and to identify the impact achieved by rehabilitation.⁷⁵

To calculate the HR for exercise, we suggest the Karnoven formula which takes into account values at rest, heart reserve and maximum reached level.

The tests used to determine which intensity of aerobic exercise should be indicated are the Incremental Test (IT) with a treadmill or cycle ergometer and the Constant Load Test (CLT). The IT is sensitive to interventions and has prognos­tic implications depending on the severity of the patient.⁷⁵ The CLT is the most sensitive tool to detect the impact of RRPs on respiratory diseases of various origins.⁷⁵

In the evaluation of muscle strength and nutri­tional status, the in-person modality allows the use of machines, free weight or functional assessment implements such as suspension straps, exercise balls, bosu balls and body-weight exercise.^44,45

Regarding the nutrition advice, if the neces­sary resource is available, it would be desirable to have an anthropometric measurements form that allows the analysis of the intervention effects on the patient’s body composition.

For the DLA evaluation we suggest the PCFS in the first place; the Barthel and Katz indices can be a second option, and finally, the 36-Item Short Form Health Survey (SF-36) and the Saint George’s Respiratory Questionnaire (SGRQ) could be an alternative. The HAD questionnaire can be used for the psychological evaluation.

The following table summarizes the in-person rehabilitation aspects.

3. How to rehabilitate a patient with pCS and PS?

There isn’t a generalized consensus on which is the best modality for the rehabilitation of patients with pCS and PS. One concept must be emphasized in this section.

Several publications suggest which type of training could be used through telerehabilitation and in-person rehabilitation, and include not only peripheral muscle training but also nutritional and psychological support and aspects related to the patient’s education.^{30,52,53,57,58,63,66-70}

A. Respiratory rehabilitation with the remote modality

Telemedicine has provided recommendations for the section about respiratory rehabilitation, both in the case of an exercise program remotely supervised by a professional and also in the case of a non-supervised protocol.^69,70

Exclusion criteria for remote respiratory reha­bilitation of patients with pCS are:⁶⁹

• Poor cognitive status (Mini-Mental State Ex­amination ≤ 24 points).

• Presence of unstable heart or neurologic disease.

• Severely altered range of motion or other mus­culoskeletal defects preventing the patient from making the requested gestures.

• Disabled patients who live alone and don’t have any help.

• Patients with evident balance disorders.

• Patients without basic knowledge about the management of devices for remote contact.

A1. Asynchronous remote respiratory rehabilitation

Information about which type of exercise should be done and how to do it is provided through videos or workout charts that must be given to the patients. Also, a form must be given to patients containing all the exercises they have to do. The patient has to record the level of dyspnea and fatigue he/she felt in each exercise of the session, according to the Borg scale. If possible, the patient should also record SpO2 and HR levels at the end of each walk or set of exercises.^44,65,69

The educational and psychological support converge with muscular training to shape this remote RRP.

The following table describes the important aspects of this rehabilitation modality.^{44,45,66,69,79,80}

A2. Synchronous remote respiratory rehabilitation

With this modality, the professional can supervise the work of the patient/s in two ways:

On one hand, by connecting to a video-confer­ence with groups of 4-6 participants and observ­ing how they are doing the activity. On the other hand, connecting individually with the patient and supervising him/her 2 (two) times a week while he/she does the activity, leaving other two weekly sessions in charge of the patient himself/ herself.⁶⁹

B. Respiratory rehabilitation through the in-person modality

Once the patient finishes his/her evaluation, the professional has to be able to decide which train­ing modality is most suitable for that patient in particular.

B1. Aerobic resistance training

Although there isn’t any specific protocol for this type of training in patients who suffered from COVID-19 disease, we suggest the training mo­dalities commonly used for patients with diffuse interstitial lung diseases (DILDs), because they bear some similarity to the pulmonary damage caused by SARS-CoV-2 and PICS.

In this context, both the Continuous Variable Method (CVM) and the Intermittent Method can be used.⁸¹

A recent update of the Cochrane Database of Systematic Reviews regarding the RR in DILDs included 16 studies with 357 DILD patients and a control group of 319 individuals.⁸¹ The rehabilita­tion improved the 6MWT with a mean of 40 (± 32.7- 47.4) meters, the capacity to work, oxygen consump­tion, dyspnea and DLAs measured by the SGRQ and CRQ (Chronic Respiratory Questionnaire), benefits which in five studies persisted between 6-12 months after finishing the intervention.⁸²

B2. Muscle strength training

Whether they use training machines, free weights or functional training elements, patients can begin muscle strength training with weights that ac­count for 50% of the maximal tolerated strength of the evaluation, commonly based on Epley or Brzycki 1-rep max formulas, then increasing up to 12 reps, and then 3 sets with 80% of maximum estimated strength.^44,81,82

B3. Psychological and nutritional support

With this in-person modality, we recommend educational meetings about the aspects related to posture, dyspnea and cough management in DLAs, breathing rhythm, energy-conservation techniques when doing physical exercise, suitable use of can­nulas and oxygen masks, how to recognize signs of alarm during physical activities, among other topics of interest.^{30,44,52,53,55,57,58,63,66,68,69,78,79,81}

B4. Psychological support

This in-person modality includes a psychopatholo­gist who is familiar with the problems of these patients.^{30,44,52,53,55,57,58,63,66,68,69,78,79,81}

CONCLUSIONS

The approach to patients with moderate and severe forms of SARS-CoV-2 disease involves recognizing the systemic aspect of the condition, its frequently incapacitating character and its wide community spread.

At present, the respiratory rehabilitation is the only intervention that has shown a positive impact on patients’ dyspnea and fatigue and quality of life, as well as an improvement in the psychological sphere. Despite those benefits, both the indica­tion and use of respiratory rehabilitation are still strongly underestimated.

Whatever the medical complexity level where it is to be applied, we suggest that it is administered at an early stage, in an integrated and continuous way, during the transfer from one level of care to another, and in so far as it is possible, with the participation of a multidisciplinary team consist­ing of kinesiologists, physicians, nutritionists and psychologists.

Evaluation and training must focus on the patient’s needs and possibilities. This includes previous knowledge of the environment where the patient is going to continue the intervention, that is to say, if it is going to be remote or in-person; the use of safe and simple techniques with every­day objects, the analysis of the clinical condition of the patient starting the rehabilitation and the feasibility of the proposed strategy basing on the knowledge of the patient and his/her environment. Finally, the healthcare team must respect the ethical principles of privacy, confidentiality and of being informed about the expectations and results of the suggested intervention.

To conclude, this workgroup believes that the first duty of the rehabilitation team is to become the bridge that provides patients affected by SARS-CoV-2 accessibility to the only valid tool they can have in order to minimize their sequelae and improve their quality of life: respiratory re­habilitation.

Conflict of interest

Authors have no conflict of interest to declare.

REFERENCES

1. Li Q, Guan X, Wu P, et al. Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected Pneumonia. N Engl J Med. 2020;382:1199-207.

2. WHO Director.General opening remarks at the media briefing on COVID-19: 11 March 2020. Published March 11 2020. Disponible en: https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020

3. John Hopkins Coronavirus Resource Center. Disponible en: https://coronavirus.jhu.edu/

4. Las 10 principales causas de defunción. Disponible en: https://www.who.int/es/news-room/fact-sheets/detail/the-top-10-causes-of-death

5. Estadísticas-mortalidad. Disponible en: https://www.argen­tina.gob.ar/salud/instituto-nacional-del-cancer/estadisticas/mortalidad

6. Ministerio de Salud de la Nación. Boletín Integrado de Vigilancia N540 SE 10/2021. Disponible en: https://bancos. salud.gob.ar/recurso/boletin-integrado-de-vigilancia-n540-se10-2021

7. Schönfeld D, Arias S, Bossio JC, Fernández H, Go­zal D, Pérez-Chada D. Clinical presentation and out­comes of the first patients with COVID-19 in Argen­tina: Results of 207079 cases from a national database. Disponible en: https://journals.plos.org/plosone/article/authors?id=10.1371/journal.pone.0246793

8. Abate SM, Ahmed Ali S, Mantfardo B, Basu B. Rate of In­tensive Care Unit admission and outcomes among patients with coronavirus: A systematic review and Meta-analysis. PLoSOne 2020;15(7). https://doi.org/10.1371/journal.pone.0235653

9. Osuchowski MF, Winkler MS, Skirecki T et al. The COV­ID-19 puzzle: deciphering pathophysiology and phenotypes of a new disease entity. Lancet Respir Med 2021;9:622-42. https://doi.org/10.1016/S2213-2600(21)00218-6.

10. Hou YJ, Okuda K, Edwards CE, et al. SARS-CoV-2 re­verse genetics reveals a variable infection gradient in the respiratory tract. Cell 2020;182:429-46.e14. https://doi.org/10.1016/j.cell.2020.05.042

11. Tang X, Du RH, Wang R, et al. Comparison of hospi­talized patients with ARDS caused by COVID-19 and H1N1. Chest 2020;158:195–205. https://doi.org/10.1016/j.chest.2020.03.032

12. Ellinghaus D, Degenhardt F, Bujanda L, et al. Genome wide association study of severe Covid-19 with respira­tory failure. N Engl J Med 2020;383:1522–34. https://doi.org/10.1056/NEJMoa2020283

13. Yu M, Liu Y, Xu D, Zhang R, Lan L, Xu H. Prediction of the development of pulmonary fibrosis using serial thin-section CT and clinical features in patients dis charged after treatment for COVID-19 pneumonia. Korean J Radiol 2020;21:746–55. https://doi.org/10.3348/kjr.2020.0215

14. Wilson MS, Wynn TA. Pulmonary fibrosis: pathogenesis, etiology and regulation. MucosalImmunol 2009;2:103-21. https://doi.org/10.1038/mi.2008.85

15. Akoumianaki E, Dousse N, Lyazidi A, et al. Can propor­tional ventilation modes facilitate exercise in critically ill patients? A physiological cross-over study: Pressure support versus proportional ventilation during lower limb exercise in ventilated critically ill patients. Ann Intensive Care 2017;7:64. https://doi.org/10.1186/s13613-017-0289-y

16. Nydahl P, Sricharoenchai T, Chandra S, et al: Safety of patient mobilization and rehabilitation in the intensive care unit. Systematicreviewwith meta-analysis. Ann Am Thorac Soc 2017;14:766-77. https://doi.org/10.1513/AnnalsATS.201611-843SR

17. Devlin JW, Skrobik Y, Gélinas C, et al. Clinical practice guidelines for pain management, agitation/sedation, delirium, immobility and sleep disturbances in adult patients in the ICU. PADIS Method Innovations Paper. Crit Care Med 2018;46:1457-63. https://doi.org/10.1097/CCM.0000000000003298

18. Mart MF, Brummel NE, Ely EW. The ABCDEF Bundle for the Respiratory Therapist. Respir Care. 2019;64:1561-73. https://doi.org/10.4187/respcare.07235

19. Stiller K, Phillips A. Safety aspects of mobilising acutely ill inpatients. Physiother Theory Pract 2003;19:239-57. https://doi.org/10.1080/09593980390246751

20. Jones PW, Bestall JC. Modified Medical Research Coun­cil scale. Thorax 1999;54:581-6. https://doi.org/10.1136/ thx.54.7.581

21. Medical Research Council of the UK, Aids to the investi­gation of Peripheral Nerve Injuries, Memorandum No.45. London, Pendragon House 1976: 6-7.

22. Ely E, Truman B, Shintani A, et al. Monitoring Se­dation Status Over Time in ICU Patients: Reliability and Validity of the Richmond Agitation-Sedation Scale (RASS). JAMA 2003;289:2983-91. https://doi.org/10.1001/jama.289.22.2983

23. Latorre Marco, M. Solís Muñoz, T. Falero Ruiz, et. al. Valida­tion of the Scale of Behavior Indicators of Pain (ESCID) in critically ill, non-communicative patients under mechanical ventilation: results of the ESCID scale. Enferm Intensiva 2011;22:3-12.

24. Ely EW, Inouye SK, Bernard GR, et al. Delirium in Me­chanically Ventilated Patients. Validaty and Reliability of the Confusion Assessment Method for the Intensive Care

Unit (CAM-ICU). JAMA 2001;286:2703-10. https://doi.org/10.1001/jama.286.21.2703

25. Morris PE, Goad A, Thompson C, et al. Early intensive care unit mobility therapy in the treatment of acute respira­tory failure. Crit Care Med 2008;36:2238-43. https://doi.org/10.1097/CCM.0b013e318180b90e

26. Moss M, Nordon-Craft A, Malone D, et al. A randomized trial of an intensive physical therapy program for patients with acute respiratory failure. Am J Respir Crit Care Med 2016;193:1101-10. https://doi.org/10.1164/rccm.201505-1039OC

27. Ortiz Calderón M, Páez Pineda O. Prevención y Manejo del desacondicionamiento físico en el paciente hospi­talizado por Covid-19. Ed: Universidad Pedagógica y Tecnológica de Colombia. Versión electrónica. Colombia. Julio 2020.

28. Fuke R, Hifumi T, Kondo Y, et al. Early rehabilitation to pre­vent post intensive care syndrome in patients with critical illness: A systematic review and meta-analysis. BMJ Open 2018;8:1-10. https://doi.org/10.1136/bmjopen-2017-019998

29. Klok FA, Boon GJAM, Barco S, et al. The Post-COVID-19 Functional Status scale: atool to measure functional status over time after COVID-19. Eur Respir J 2020;56:2001494. https://doi.org/10.1183/13993003.01494-2020

30. Barker-Davies R, O’Sullivan O, Senaratne K, et al. The Stanford Hall consensus statement for post-COVID-19 rehabilitation. Br J Sports Med. 2020:54:949-59. https://doi.org/10.1136/bjsports-2020-102596

31. Hong Mei Z, Yu Xiao X, Chen W. Recommendations for re­spiratory rehabilitation in adults with coronavirus disease 2019. Chin Med J (Engl) 2020;133:1595-602. https://doi.org/10.1097/CM9.0000000000000848

32. Wang T, Chau B, Lui M, et al. Physical Medicine and Reha­bilitation and Pulmonary Rehabilitation for Covid-19. Am J Phys Med Rehabil. 2020;99:769-74. https://doi.org/10.1097/PHM.0000000000001505

33. Stiller K, Phillips A. Safety aspects of mobilising acutely ill inpatients. Physiother Theory Pract 2003;19:239-57. https://doi.org/10.1080/09593980390246751

34. Díez Burón F, Marcos Vidal JM, Baticón PM. Concordancia entre la escala verbal numérica y la escala visual analógica en el seguimiento del dolor agudo postoperatorio. Rev Esp Anestesiol Reanim 2011;5:279-82. https://doi.org/10.1016/S0034-9356(11)70062-7

35. Núñez-Cortés R, Rivera-Lillo G, Arias- Campoverde M. Use of sit-to-stand test to assess the physical capacity and exertional desaturation in patients post COVID-19. Chron Respir Dis. 2021;18:1479973121999205. https://doi.org/10.1177/1479973121999205

36. Maddocks M, Nolan CM, Man WD. Man. Simple function­altests in COPD: stand up and be counted! Eur Respir J 2017;49:1700104. https://doi.org/10.1183/13993003.00104-2017.

37. Beauchamp MK, Hill K, Goldstein RS, et al. Impairments in balance discriminate fallers from non-fallers in COPD. Respir Med. 2009;103:1885-91. https://doi.org/10.1016/j.rmed.2009.06.008

38. Kon SS, Canavan JL, Nolan CM. The 4 metregait speed in COPD: responsiveness and minimal clinically important difference. Eur Respir J. 2014;43:1298-305. https://doi.org/10.1183/09031936.00088113

39. Mador MJ , Mogri M , Patel A. Contractile fatigue of the quadriceps muscle predicts improvement in exercise per­formance after pulmonary rehabilitation. J Cardiopulm Rehabil Prev. 2014;34:54-61. https://doi.org/10.1097/HCR.0000000000000023

40. Ehlenz H, Grosser M, Zimmerann E. La Resistencia desde una Perspectiva Práctica del Entrenamiento. En: Entre­namiento de la Fuerza. 2º ed. Ed. Martínez Roca S.A. 1990, p 103-11.

41. Boeckh-Behrens WU, Buskies W. Control del esfuerzo según el porcentaje de la fuerza máxima. En: Entrenamiento de la Fuerza. Editorial Paidotribo. Barcelona España año 2005, p 64-69

42. Mahoney FI, Barthel DW. Functional evaluation: the Barth­el index. Md Med J. 1965;14:61-65. https://doi.org/10.1037/t02366-000

43. Katz S, Ford A, Moskowitz R, Jackson B, Jaffe M. Stud­ies of illness on the aged. The index of ADL: a stan­dardized measure of biological and psychological func­tion. JAMA 1963;185:914-9. https://doi.org/10.1001/jama.1963.03060120024016

44. Rodríguez Núñez I, Torres Castro R, Vera R. Consenso de Rehabilitación Respiratoria en pacientes con Co­vid-19. Sociedad Chilena de Kinesiología Respiratoria (SOCHIKIR). Chile. Agosto 2020. https://doi.org/10.13140/ RG.2.2.16594.17607/1

45. Saadia Otero MA. El Entrenamiento Físico en la Reha­bilitación Respiratoria, un Programa Diferente. Editorial Académica Española. 2017 p 16-19.

46. Vega ML, Sirotti C, Montiel G, et al. Recomendaciones para el manejo invasivo y no invasivo de la insuficiencia respi­ratoria hipoxémica por COVID-19. Número especial de la Revista Educativa de ALAT. Asociación Latinoamericana de Tórax, ALAT. Mayo 2020

47. Bowers R, Fox E. Procesos de recuperación. En: Fisiología del Deporte. 3o ed. México. Editorial Médica Panamericana, 1998 p 54-69.

48. Zintl F. Conceptos fundamentales de la teoría del entre­namiento. En: Entrenamiento de la Resistencia – Fun­damentos, métodos y dirección del entrenamiento. 2o ed. Barcelona, España Editorial Martínez Roca, S.A. 1991 p 110-113

49. Peña G, Heredia Elvar JR, Moral S, Mata F y Marzo Edir Da Silva G. Evidencias sobre los Efectos del Entrenamiento Inestable para la Salud y el Rendimiento. PubliCE Stan­dard. 2012

50. Willardson JM. Core Stability Training: applications to sports conditioning programs. J Strength Cond Res 2007;21:979-85. https://doi.org/10.1519/00124278-200708000-00054

51. Fajardo J. ¿Qué es la musculación y dónde ubicarla? Nuevas Tendencias en Fuerza y Musculación, 1 ed. Autor Editor Julio Tous Fajardo, 1999, p 37-5272 273

Respiratory Rehabilitation and SARS-CoV-2

52. Societat Catalana de Medicina Familiar i Comunitària (CAMFiC). Manifestaciones Persistentes de la Covid-19. Guía de Práctica Clínica. Edición 2020.

53. Guía Clínica para la atención del paciente Long COVID/ COVID Persistente, 1-5-2021. Documento colaborativo en­tre colectivos de pacientes y sociedades científicas. Versión 1.0. Fecha: 1-5-2021.

54 Patient-Led Research Collaborative. Report: What Does COVID-19 Recovery Actually Look Like? An Analysis of the Prolonged COVID-19 Symptoms Survey by Patient-Led R Research Team. Disponible en: https://patientresearchco­vid19.com/research/report-1/.

55. Greenhalgh, T, Knight M, A’Court M, Buxton M, Husain L. Management of post-acute COVID-19 in primary care. BMJ 2020;370:m3026. https://doi.org/10.1136/bmj.m3026.

56. Fernández-de-Las-Peñas C, Palacios-Ceña D, Gómez- Mayordomo V, Cuadrado ML, Florencio LL. Defining post-COVID symptoms (post-acute COVID, long COVID, persistent post-COVID): An integrative classification. Int J Environ Res Public Health. 2021;18:2621. https://doi.org/10.3390/ijerph18052621.

57. National Institute for Health and Care Excellence, Practi­tioners of RC of G, Scotland HI. COVID-19 rapid guideline: managing the long-term effects of COVID-NICE Guide (Internet) 2020; 18 December 2020: 1-35. Disponible en: https//www.nice.org.uk/guidance/ng188/resources/covid19-rapid-guidance-managing- the-longterm-effects-of-covid19-pdf66142028400325.

58. Rajan S, Khunti K, Alwan N et al. In the way for the pan­demic preparing for long COVID (Internet) HEALTH SYS­TEMS AND POLICY ANALYSIS POLICY 2020. Cited 2021 Mar 12. Disponible en:https://apps.who.int/iris/bitstream/handle/10665/339629/Policy-brief-39-1997-8073- eng.pdf.

59. Maltezou H, Pavli A, Tssakris A. Post-COVID Syndrome: An Insight on Its Pathogenesis. Vaccines 2021;9:497. https://doi.org/10.3390/vaccines9050497.

60. Lopez-Leon S, Wegman-Ostrosky T, Perelman C, et al. More than 50 Long-term effects of COVID-19: a systematic review and meta-analysis. medRxivpreprintdoi: https://doi.org/10.1101/2021.01.27.21250617.

61. Davis HE, Assafi GS, McCorkelli L, et al. Characterizing Long COVID in an International Cohort: 7 Months of Symptoms and Their Impact. 2021:101019 https://doi.org/10.1101/2020.12.24.20248802

62. Sociedad Española de Médicos Generales y de Familia (SEMG). Colectivo de pacientes Long COVID (ACTS). Encuesta de síntomas y discapacidad producida por los mis­mos, en los afectados por COVID persistente. Disponible en: https://www.semg.es/images/2020/Noticias/20201111_Re­sultados_Encuesta_COVID_Persistente.pdf.

63. Documento intersociedades. Desafío pospandemia COVID. Recomendaciones para la rehabilitación pos COVID19. Ministerio de Salud y Bienestar Social, Argentina.

64. Sudre C, Murray B, Varsasky t, et al Attributes and predic­tors of Long-COVID: analysis of COVID cases and their symptoms 2 collected by the Covid Symptoms Study App. https://doi.org/10.1101/2020.10.19.20214494.

65. Greenhalgh T, Javid B, Knight M, et al. What is the efficacy and safety of rapid exercise tests for exertional desaturation in covid-19? Oxford COVID-19 Evidence Service. 2020

https://www.cebm.net/covid-19/what-is-the-efficacy-and-safety-of-rapid-exercise-tests-for-exertional-desaturation-in-covid-19/

66. Spruit MA, Holland AE, Singh SJ, Tonia T, Wilson KC, Troosters T. COVID-19: interim guidance on rehabilita­tion in the hospital and post-hospital phase from a Eu­ropean Respiratory Society- and American Thoracic Society-coordinated international task force. Eur Respir J 2020;56:2002197. https://doi.org/10.1183/13993003.02197-2020.

67. Brennan D, Tindall L, Theodoros D, et al. A blueprint for telerehabilitation guidelines. International journal of telerehabilitation 2010;2:31-4. https://doi.org/10.5195/ ijt.2010.6063

68. Vitacca M, Lazzeri M, Guffanti E et al. An Italian con­sensus on COVID-19 patients recovering from acute respiratory faillure : results of a Delphy process. Monaldi Arch Dis 2020;90:1444:385-93. https://doi.org/10.4081/monaldi.2020.1444

69. Agency for Clinical Evaluation. NSW Governement. De­livering pulmonary rehabilitation via Telehealth during COVID-19. Virtual PuRe. April 2020. Disponible en: www.aci.health.nsw.gov.au.

70. Almonacid C, Plaza V. Guía SEPAR para la teleconsulta de pacientes respiratorios. Disponible en:https://www.separ.es/node/1974.

71. Vaidya T, Chambellan A, De Bisschop C. Sit-to-Stand Test on COPD: A literature review. Resp Med 2017;128:70-7. https://doi.org/10.1016/j.rmed.2017.05.003

72. Quintana JM, Padierna A, Esteban C, ArosteguiI, Bilbao A, Ruiz I. Evaluation of the psychometric characteristics of the Spanish version of the Hospital Anxiety and Depression Scale. Acta Psychiatr Scand 2003;107:216–21. https://doi.org/10.1034/j.1600-0447.2003.00062.x

73. Terol Cantero MC, Cabrera Perona V, Martín-Aragón M. Revisión de estudio de la Escala de Ansiedad y Depresión Hospitalaria (HAD). Anales de Psicología 2015;31:494-503. http://dx.doi.org/10.6018/analesps.31.2.172701.

74. ATS Committee on Proficiency Standards for Clini­cal Pulmonary Function Laboratory. ATS statement: guidelines for six minute walk test. Am J Respir Crit Care Med. 2002;166:111-17. https://doi.org/10.1164/ajrccm.166.1.at1102

75. Puente-Maestu LP, PalangeP, Casaburi R et al. Use of exer­cise testing in the evaluation of interventional efficacy : an official ERS statement. Eur Resp J 2016;47:429-60. http://dx.doi.org/10.1183/13993003.00745-2015.

76. Alonso J, Prieto L, Anto JM. La versión española del SF-36 HealthSurvey (Cuestionario de Salud SF-36): un instru­mento para la medida de los resultados clínicos. Med Clin (Barc). 1995;104:771-6

77. Jones PW, Quirk FH, Baveystock CM. The St George’s re­spiratory questionnaire. Respir> Med 1991;85:25-31. https://doi.org/10.1016/S0954-6111(06)80166-6

78. Curci C, Pisano F, Bonacci E, Camozzi DM, Ceravolo C, Ber­gonzi R, et al. Early rehabilitation in post-acute COVID-19 patients: data from an Italian COVID-19 Rehabilitation Unit and proposal of a treatment protocol. Eur J Phys Rehabil Med 2020;56:633-41. http://dx.doi.org/10.23736/ S1973-9087.20.06339-X.

79. Liverpool Heart and Chest Hospital. NHS Foundation Trust. COVID-19 Patient Rehabilitation Guide. https:// www.lhch.nhs.uk/media/7300/covid19-rehabilitation-guide.pdf.

80. Ainsworth B, Haskell W, Herrmann S et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. http://dx.doi.org/10.1249/ MSS.0b013e31821ece12.

81. Capparelli I, Saadia Otero M, Steimberg J, et al. Rehabili­tación respiratoria en pacientes con enfermedad pulmonar intersticial difusa, experiencia de un hospital especializado de Argentina. Rev Am Med Resp 2019;19:291-7.

82. Dowman L, Hill CJ, May A, Holland A. Rehabilitación pulmonar para la enfermedad pulmonarintersticial. Disponible en:https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006322.pub4/full/es.