Physiotherapy in Critical Care in Australia

Abstract

A physiotherapist is part of the multidisciplinary team in most intensive care units in Australia. Physiotherapists are primary contact practitioners and use a comprehensive multisystem assessment that includes the respiratory, cardiovascular, neurological, and musculoskeletal systems to formulate individualized treatment plans. The traditional focus of treatment has been the respiratory management of both intubated and spontaneously breathing patients. However, the emerging evidence of the longstanding physical impairment suffered by survivors of intensive care has resulted in physiotherapists re-evaluating treatment priorities to include exercise rehabilitation as a part of standard clinical practice. The goals of respiratory physiotherapy management are to promote secretion clearance, maintain or recruit lung volume, optimize oxygenation, and prevent respiratory complications in both the intubated and spontaneously breathing patient. In the intubated patient, physiotherapists commonly employ manual and ventilator hyperinflation and positioning as treatment techniques whilst in the spontaneously breathing patients there is an emphasis on mobilization. Physiotherapists predominantly use functional activities for the rehabilitation of the critically ill patient in intensive care. While variability exists between states and centers, Australian physiotherapists actively treat critically ill patients targeting interventions based upon research evidence and individualized assessment. A trend toward more emphasis on exercise rehabilitation over respiratory management is evident.

INTRODUCTION

A physiotherapist is part of the multidisciplinary team in most intensive care units in Australia.^1,2 They are primary contact practitioners and use a comprehensive multisystem assessment that includes the respiratory, cardiovascular, neurological, and musculoskeletal systems to formulate individualized treatment plans.³ Physiotherapists provide treatment for respiratory complications including the application of noninvasive ventilation and exercise and rehabilitation for the prevention and management of intensive care acquired weakness (ICUAW) and deconditioning associated with immobility.⁴ Traditionally the management of respiratory complications such as retained pulmonary secretions, atelectasis, and the avoidance of reintubation has been the major focus of physiotherapy treatment for the critically ill patient. However, the emergence of evidence reporting that many survivors of intensive care suffer long standing weakness and functional limitation as a result of their critical illness has caused physiotherapists to re-evaluate treatment priorities and include exercise rehabilitation as a part of standard clinical practice.¹

A mix of public and private health care providers delivers health care in Australia. Health care is funded nationally under a system called Medicare that covers all Australian citizens although individuals have a choice of opting for additional private health insurance using a private sector health provider.⁵ Public hospitals are directly funded by government. Health care that includes access to a bed, medical, nursing, allied health including physiotherapy and ancillary services is provided free of charge. There are a relatively small number of private hospitals with the majority of acute care and emergency beds located in public hospitals. More complex advanced care occurs predominantly in the metropolitan public hospitals, although increasingly, larger private hospitals are providing more complex care including intensive care.⁵

Intensive care units in Australia are classified from level one to 3 (Table 1) with level 3 being able to provide the most advanced life support services. Units are staffed by Intensive Care Specialists and a mix of junior and more senior medical staff who may be involved in a speciality training program. Nurses may have a tertiary certificate in critical care and are staffed on a 1:1 ratio for ICU beds and 1:2 for high dependency beds where patients do not require mechanical ventilation or renal replacement therapy. The average cost of an ICU bed is $2500-$3000 (AUD) per day and this comprises approximately 20% of hospital expenditure.⁶

Table 1.

Intensive Care Unit Levels in Australia

Level	Definition
Level 3	Must be capable of providing complex, multisystem life support for an indefinite period; must be a tertiary referral centre for patients in need of intensive care services and have extensive back-up laboratory and clinical service facilities to support the tertiary referral role. Must also be capable of providing mechanical ventilation, extracorporeal renal support services and invasive cardiovascular monitoring for an indefinite period, or care of a similar nature.
Level 2	Must be capable of providing complex, multisystem life support, and be capable of providing mechanical ventilation, extracorporeal renal support services and invasive cardiac monitoring for a period of at least several days, or longer periods in remote areas, or care of a similar nature.
Level 1	Must be capable of providing basic multisystem life support usually for less than 24 hours. Must also be capable of providing mechanical ventilation and simple invasive cardiac monitoring for a period of at least several hours, or care of a similar nature.

Most intensive care units in Australia have at least one senior physiotherapist on staff and almost half of these physiotherapists have greater than 5 years of critical care experience.^1,2 Whilst many have research experience in ICU, few have research higher degrees.^1,2 No specific additional training is required for physiotherapists to work in ICU in Australia. Staffing profile is dependent on the level of the unit based on the intensity of medical care provided, the number of beds, and the availability of physiotherapy staff.⁷ Physiotherapy services are generally provided each day or part thereof from 0800–1700. A small number of units have the provision for a 24 hour or after hours service.⁷ Most physiotherapists in Australia are able to initiate assessment and treatment without medical and/or nursing referral as part of the multidisciplinary team.²

ROLE OF THE PHYSIOTHERAPISTS: RESPIRATORY MANAGEMENT

The goals of respiratory physiotherapy management are to promote secretion clearance, maintain or recruit lung volume, optimize oxygenation and prevent respiratory complications in both the intubated and spontaneously breathing patient.³

The Intubated Patient

Respiratory dysfunction in the intubated patient is characterised by the underlying pathology; altered respiratory mechanics due to the effects of positive pressure ventilation, ventilation and perfusion mismatch,⁸ and mucociliary dysfunction.⁹ Patients who are intubated and ventilated are at risk of developing secretion retention due to the disturbance of normal secretion clearance, subsequent atelectasis and ventilator associated pneumonia.⁹ Respiratory physiotherapy aims to treat or prevent these sequelae using a number of different techniques.

Manual Hyperinflation

Manual hyperinflation (MHI) has been commonly used by Australian physiotherapists for the treatment of sputum retention and pulmonary collapse since the early 1970s.^10,11 It involves the delivery of larger than baseline tidal volumes to a peak airway pressure of 40 cmH₂O to patients who are intubated using a manual resuscitation bag^12,13 (Figure 1). The technique is achieved by delivering a slow inspiratory flow, followed by a 2–3-second inspiratory hold and a fast uninterrupted expiratory flow that mimics a forced expiration.¹⁴ It has been proposed that in order to achieve the cephalad movement of pulmonary secretions that expiratory flow must exceed inspiratory flow by more than 10%¹⁵ and be sufficient to achieve a velocity of greater than 1000 cm/second to move pulmonary secretions. The interpretation and synthesis of results of studies examining the effects of MHI have been limited by differences in definition, dosage, and technique;^3,14,18,19 nonetheless, MHI has been consistently shown to improve static pulmonary compliance, secretion removal, reduce airways resistance, and recruit pulmonary collapse.^{10,13,17,20,21,22} The dosage of MHI reported in the literature varies from 6 cycles of 6 breaths¹⁶ to 2 cycles of 6 breaths.²³

Figure 1.

Physiotherapist performing manual hyperinflation.

Ventilator Hyperinflation

The beneficial effects of MHI can also be achieved by altering the settings on the patient's ventilator.^13,24 One of the major advantages of performing ventilator hyperinflation (VHI) in comparison to MHI is the maintenance of positive end expiratory pressure, and the reproducibility of the technique.^13,24 Recent survey evidence from senior ICU physiotherapists in Australia reported that up to 39% of ICUs use VHI, predominantly as a technique for pulmonary secretion clearance.²⁵ Dennis et al²⁶ reported that VHI was performed in both controlled and spontaneous modes of ventilation by altering ventilatory parameters. In the spontaneous mode, VHI is achieved by incremental increases in pressure support and in control modes by either altering pressure or volume limits to reach a predetermined target volume or pressure. Australian physiotherapists demonstrate broad agreement about the indications and application of VHI in clinical practice.²⁵

Positioning

The application of both MHI and VHI is most frequently and effectively delivered with the patient in a side lying position with the affected lung uppermost.^16,25,26 The side lying position results in an increase in lung volume to the uppermost lung that enhances recruitment and facilitates drainage from broncho-pulmonary segments and depending on lung pathology, may improve gas exchange.²⁷ Regular turning into the side lying position has also been associated with a reduction in the incidence of ventilator associated pneumonia (VAP) provided that greater than 40° of lateral turn is achieved.²⁸

The addition of a side lying position has been shown to significantly increase sputum yield compared to the supine position when using MHI.²⁶ Adding a head down tilt in side lying has been reported to increase sputum clearance by up to 25% in our cross-over study of 20 patients who were intubated and ventilated.¹⁶ Although there was wide variation, the addition of a head down tilt did not reduce peak expiratory flow which is important if we accept the theory that sufficient expiratory flow is required to achieve movement of pulmonary secretions in the airways. We were able to demonstrate, using an inspiratory flow obtained in a similar group of patients that the expiratory flow produced during MHI in both the side lying and head down tilt positions was at least 10% higher than inspiratory flow and sufficient to produce velocities in excess of 1000 cm/sec.¹⁶ We therefore contend that if secretion clearance is the primary aim of treatment that a head down tilt should be used provided no contraindications are present.

Manual Techniques

The extent and use of manual techniques by physiotherapists in ICU in Australia was last reported 10 years ago.⁷ At this time both chest wall percussion and vibration were used by up to 80% of physiotherapists, often in combination with MHI.^11,21 Since this time, there has been a relative exponential increase in the research output and application of MHI and VHI in clinical practice in Australia and the use of manual techniques has not been reported recently.

Most research into the effectiveness of manual physiotherapy techniques has been undertaken in medical patient populations with excessive secretion production.²⁹ The efficacy of chest wall percussion has not been investigated in an Australian critical care population. In contrast, chest wall vibration in ICU has been investigated by two Australian physiotherapists.^21,30 This technique involves the production of large and small oscillatory movements performed during expiration that aim to increase expiratory flow and subsequent pulmonary secretion clearance.²⁹ Stiller et al²¹ reported that the addition of vibrations to MHI did not further enhance the resolution of atelectasis and Ntoumenopoulos et al³¹ found that chest wall vibration in combination with positioning was associated with a reduction in rates of VAP by 27%.

Suctioning

Tracheal suctioning is used during a physiotherapy treatment to clear pulmonary secretions.⁸ It has been associated with episodic hypoxemia and cardiac arrhythmias³¹ that may have previously been attributed to the effects of the physiotherapy treatment.^32,33 The metabolic effects of a physiotherapy treatment that included VHI, side lying and endotracheal suctioning reported that the greatest increases in oxygen consumption were recorded during and following the suctioning procedure.³⁴ Whilst the instillation of saline prior to suction remains controversial,³⁵ it is used selectively in clinical practice to assist in the clearance of tenacious pulmonary secretions.

Efficacy and Safety

Multimodal respiratory physiotherapy treatment as practiced by Australian physiotherapists has been shown to be safe with a prospective audit of 5 metropolitan tertiary hospitals reporting only 29 adverse physiological events occurring in 12,800 treatments (0.22%).³⁶ In addition the metabolic demands of physiotherapy treatment are no greater than turning a patient into a side lying position.³⁴

The efficacy of prophylactic multimodal physiotherapy treatment used in Australian ICUs in trauma populations has been evaluated against various clinical endpoints with conflicting results.^23,30,37 The addition of MHI in a side lying position to standard nursing and medical care has shown no significant reduction in the incidence of VAP, the duration of mechanical ventilation or ICU length of stay.^23,37 Conversely in a heterogeneous population, the addition of chest wall vibrations in a side lying position was associated with a 27% reduction in VAP, although no differences in the duration of mechanical ventilation and ICU length of stay were observed.³⁰ Differences in outcomes can be explained by the different populations and the limited sample sizes of the two studies examining MHI. Nonetheless, these studies, in combination with the emerging evidence to support the role of rehabilitation in critically ill patients, have resulted in respiratory treatment being reserved for patients presenting with atelectasis and pulmonary secretion retention rather than as routine or prophylactic intervention.

The Non-intubated Patient

Despite not requiring intubation or ventilation, patients often require intensive physiotherapy treatment in the ICU. Patients may be at risk of developing respiratory failure following extubation, admitted for routine postoperative surveillance, require treatment for postoperative pulmonary complications, or present with hypercapnic or hypoxemic respiratory failure requiring noninvasive ventilatory support.

In the postoperative setting physiotherapists aim to increase lung volume using mobilization, periodic application of noninvasive ventilation (NIV), and on occasion, deep breathing exercises.³ However, recent evidence suggests that routine respiratory physiotherapy in addition to mobilization may be of no added benefit in reducing postoperative pulmonary complications following major cardiac and upper abdominal surgery.^38,39,40 In an Australian setting, a small study of 56 patients suggested that mobilization can reduce the incidence of pulmonary complications³⁹ although the dose, frequency, and intensity have not been established. A small observational study of 50 patients reported that the time spent upright was less than 10 minutes in the first two postoperative days.⁴¹ The majority of mobilization in the postoperative setting in Australia is performed by physiotherapists.⁴¹

Although the use of continuous NIV for the treatment of hypercapnic respiratory failure and cardiogenic pulmonary edema is supported by high level evidence,^42,43 the delineation of roles regarding clinical decision making and application of the apparatus between nursing, medicine, and physiotherapy varies greatly in Australia. This is potentially dependent on the availability of physiotherapy services, the experience of clinicians and their seniority in the ICU.

The application of periodic continuous positive airways pressure (pCPAP) is used by Australian physiotherapists for the prevention and treatment of pulmonary complications such as atelectasis. The implementation and supervision of pCPAP is reported to be a shared responsibility between critical care nurses and physiotherapists.⁷ The dosage and interface used for the application for pCPAP by physiotherapists in the critical care setting is most likely dependent on the severity of respiratory failure, local unit policies, and equipment availability, although this has never been investigated.

REHABILITATION AND MOBILIZATION

The progress of intensive care medicine has resulted in significant improvements in survival rates.^44,45 Approximately 119,000 patients require admission to a general ICU in Australia each year with survival rates around 89% at hospital discharge.⁴⁶ However, the legacy of ICU survival can be significant with prolonged immobility and catabolism resulting in deconditioning, muscle atrophy, and weakness that may impact future health-related quality of life.⁴⁷ Reports of long-standing weakness, impaired physical function,^48,49,50 and institutional changes to sedation and delirium management of the critically ill^51,52,53 have resulted in increased interest in the provision of early rehabilitation to patients in the ICU. The benefits and safety of rehabilitation performed in the ICU have been reported in the US and European literature.^54,55,56 However, to date, there is a lack of evidence in the Australian setting. Currently in Australia at least 5 studies are being conducted or have been recently completed examining the outcomes of ICU survivors, the efficacy of rehabilitation on physical function and health related quality of life, and the effects of critical illness on muscle.

In Australia many different activities are defined by the term mobilization. These include sitting on the edge of the bed and out of bed, marching on the spot, and walking away from the bed.¹ These activities reflect specificity of training for functional tasks essential for independence at hospital discharge.³ Level 3 and 4 evidence from the US has reported that walking intubated and ventilated patients has reduced ICU and hospital length of stay and hospital readmission at 12 months.^57,58 The pattern and dosage of mobilization that includes walking away from the bed in patients who are intubated in Australian ICUs is unknown but is an area of current investigation.

Interventions used by Australian physiotherapists aimed at maintaining muscle strength, joint range, and function have been established using 3 surveys.^1,2,59 The most comprehensive of these was carried out by Skinner et al.¹ This group surveyed predominantly senior physiotherapists from 126 Australian ICUs and reported that 94% of therapists prescribe exercise routinely for long stay ICU patients.¹ In patients who were intubated and ventilated, the number of therapists who prescribe exercise is reduced to just over 70%. Irrespective of ventilatory status, active assisted or free active exercise was most commonly prescribed although the method to achieve this activity was varied. The main difference in approach to rehabilitation for patients who were intubated and ventilated was that mobilization away from the bed was less common with only 55% of respondents nominating it as a rehabilitation intervention compared to over 90% for patients who were spontaneously breathing.

Adjuncts to treatment that assist the movement of patients into an upright position such as a tilt table were not frequently used by physiotherapists.^1,59 These surveys reported that whilst the tilt table was considered an option for rehabilitation, physiotherapists preferred to use assisted standing or marching rating the tilt table the least preferred exercise activity¹ potentially used less than once per month or once per year.⁵⁹

Historically passive limb movements have been used by physiotherapists to maintain joint range and prevent soft tissue contracture.⁴ However, recent evidence suggests that Australian physiotherapists do not routinely prescribe passive limb movements for the critically ill.² In a survey of predominantly senior physiotherapists from 51 ICUs only one third routinely assessed joint range of movement and 14% of respondents used passive range of movement exercises. This number of responses may reflect the lack of evidence to support the technique.⁴ Assessment of joint range of motion was reserved for patients in whom there was a high degree of suspicion that range may be limited such as burns, pre-existing contracture or the presence of increased tone.²

Evidence for the use of newer modalities by Australian physiotherapists to assist rehabilitation such as cycle ergometry and neuromuscular electrical stimulation has not been established. Neuromuscular electrical stimulation has been widely established within the healthy population to prevent muscle atrophy and minimize muscle protein breakdown by improving oxidative metabolism.⁶⁰ It has been used with good effect in chronic inflammatory diseases, such as chronic heart failure and chronic obstructive pulmonary diseases improving quadriceps strength, physical function, and health-related quality of life. There have been 4 primary studies to date investigating neuromuscular electrical stimulation in the ICU population with conflicting results of effectiveness.^61,62,63,64 Cycle ergometry can be used passively or actively. A recent randomised controlled trial examined the effect of cycle ergometry in critically ill patients and reported improvements in quadriceps strength and physical function at acute hospital discharge.⁵⁴ However the intervention did not begin until two weeks postadmission and there were no data reporting frequency of active versus passive cycling. It is currently unknown whether passive cycling has any impact on muscle characteristics. Both neuromuscular electrical stimulation and cycle ergometry are currently being evaluated in prospective randomised trials in Australian ICUs. The results of these trials will influence future uptake of these and other rehabilitation interventions.

Outcome Measurement

A major finding of the survey of Skinner and colleagues¹ was a lack of consistent outcome measurement by physiotherapists to evaluate the effects of their exercise intervention. Whilst the majority of physiotherapists prescribed exercise routinely for patients in ICU, only one third of therapists used any form of outcome measure for exercise prescription, progression, or assessment of overall efficacy. Outcomes that were monitored for safety and exercise modification were heart rate and oxygen saturation.¹

Since the results of Skinner and colleagues¹ were published, the Physical Function in ICU Test (PFIT) has been reported.⁶⁵ This multidimensional test of function, strength, and endurance has been shown to be reliable and sensitive to change and has recently been scored. The PFIT has been incorporated into the protocol of one international and 3 Australian trials evaluating the effects of rehabilitation on functional outcome for critically ill patients. The clinometric properties of the test, including scoring, have been presented and are published in abstract form.⁶⁶

Whilst the PFIT was designed specifically for an ICU population, other tests of physical function have been used to assess the functional outcome of survivors of ICU such as the Acute Care Index of Function (ACIF), the Six Minute Walk Test, the Barthel Index, the Functional Independence Measure (FIM), and the Glittre Activities of Daily Living Test.⁶⁷ Both the FIM, using a sub-set of activities suitable for an ICU population⁶⁸ and the ACIF have been reported in the ICU cohort; however, the remaining tests were developed for other medical specialities such as rehabilitation or aged care and logistically are not suitable to be used in the ICU setting for the prescription and evaluation of exercise.

Safety and Feasibility

There have been several international reports of the safety and feasibility of mobilizing patients away from the bed side who are intubated and ventilated.^57,69,70 In an Australian setting there has been one report of the safety of mobilizing patients using specific safety criteria for initiation and progression of treatment.⁷¹ These investigators developed a guideline based on a comprehensive patient assessment that included the cardiovascular and respiratory status as well as clinical reasoning to determine readiness for mobilization. They subsequently prospectively evaluated the utility of the physiological criteria of the guideline on 31 patients who performed 69 mobilization tasks that included sitting on the edge of the bed, transferring out of bed, and mobilizing on the spot and away from the bed.⁷¹ Only on three occasions (4.3%) did a patient demonstrate clinical deterioration that required transient intervention and on no occasion was the mobilization treatment ceased. The guideline demonstrated good clinical utility and provides the only systematic approach to patient assessment of readiness for mobilization although its use in clinical practice has not been reported in Australia.

The safety and feasibility of a hierarchical protocolized exercise rehabilitation program has been reported by this author in an Australian setting.⁷² As part of a larger randomised controlled trial, rehabilitation that included cardiovascular, strength and functional training was introduced on day 5 of the ICU stay; the intensity of which was based on the results of the PFIT. These tasks were included as they reflected Australian practice.¹ Patients completed 15 minutes of exercise twice daily in the ICU with exercise progression based on Borg scores and the PFIT. Strict safety criteria for the initiation and cessation of exercise were used and no adverse events were recorded in 641 rehabilitation sessions. These results and those of Stiller and colleagues⁷¹ reflect the increasing interest in the role of mobilization and rehabilitation for critically ill patients.

Future

Mandated guidelines for the management of deteriorating patients in Australian public hospitals⁷³ have resulted in opportunities for physiotherapists to become increasingly involved in critical outreach teams. A multisystem assessment and the frequent requirement for noninvasive ventilatory support suit the skill mix of physiotherapists experienced in the care of the critically ill. This expansion of the conventional physiotherapy role may require additional education and acquisition of specific task related and diagnostic skills.

A commitment to research is essential for the growth of physiotherapy in the critical care area particularly in the role of exercise and rehabilitation. The benefits of rehabilitation for survivors of ICU in both in the short- and long-term require elucidation in randomized controlled trials. Rehabilitation should take into consideration the cognitive as well as physical function of the patients. Epidemiological studies to determine patients at risk for the development of longer term weakness and strategies to attenuate and treat weakness and impaired physical function are a priority. Further development of outcome measures that are sensitive and valid and specifically designed for critically ill patients are also necessary. The economic impact of ICU-acquired weakness and its treatment should be assessed in all future trials.

CONCLUSIONS

This paper describes the role of physiotherapists in critical care in Australia. While variability exists between states and centers, as primary care practitioners, Australian physiotherapists actively treat critically ill patients targeting interventions based upon research evidence and individualized assessment. A trend toward more emphasis on research into exercise rehabilitation over respiratory management is now evident. The outcomes of this developing evidence base will shape the direction of future roles of physiotherapists in the ICU and in follow up of ICU patients. It is important that physiotherapists lead this research, formulating questions that are based upon their extensive understanding of physical function and its importance to activities of daily living and health related quality of life.