Changes in respiratory mechanics during respiratory physiotherapy in mechanically ventilated patients

Fernanda Callefe Moreira Cassiano Teixeira Augusto Savi Rogério Xavier About the authors

RESUMO

Objetivo:

Avaliar as alterações da mecânica ventilatória e da hemodinâmica que ocorrem em pacientes dependentes de ventilação mecânica submetidos a um protocolo padrão de fisioterapia respiratória.

Métodos:

Estudo experimental e prospectivo realizado em duas unidades de tratamento intensivo, nas quais pacientes dependentes de ventilação mecânica por mais de 48 horas foram alocados, de forma consecutiva, e submetidos a um protocolo estabelecido de manobras de fisioterapia respiratória. Variáveis ventilatórias (complacência pulmonar dinâmica, resistência do sistema respiratório, volume corrente, pressão de pico inspiratório, frequência respiratória e saturação periférica de oxigênio) e hemodinâmicas (frequência cardíaca) foram mensuradas 1 hora antes (T-1), imediatamente (T0) e após 1 hora (T+1) da realização do protocolo de manobras de fisioterapia respiratória.

Resultados:

Durante o período de coleta dos dados, 104 pacientes foram incluídos no estudo. Quanto às variáveis ventilatórias, houve aumento da complacência pulmonar dinâmica (T-1 = 52,3 ± 16,1mL/cmH2O versus T0 = 65,1 ± 19,1mL/cmH2O; p < 0,001), do volume corrente (T-1 = 550 ± 134mL versus T0 = 698 ± 155mL; p < 0,001) e da saturação periférica de oxigênio (T-1 = 96,5 ± 2,29% versus T0 = 98,2 ± 1,62%; p < 0,001), além de redução da resistência do sistema respiratório (T-1 = 14,2 ± 4,63cmH2O/L/s versus T0 = 11,0 ± 3,43cmH2O/L/s; p < 0,001) logo após a realização das manobras de fisioterapia respiratória. Todas as alterações se mantiveram na avaliação realizada 1 hora (T+1) após as manobras de fisioterapia respiratória. Já com relação às variáveis hemodinâmicas, houve elevação imediata, porém não sustentada da frequência cardíaca (T-1 = 88,9 ± 18,7bpm versus T0 = 93,7 ± 19,2bpm versus T+1 = 88,5 ± 17,1bpm; p < 0,001).

Conclusão:

Manobras de fisioterapia respiratória geram mudanças imediatas na mecânica pulmonar e na hemodinâmica dos pacientes dependentes da ventilação mecânica, e as alterações ventilatórias provavelmente permanecem por pelo menos 1 hora.

Terapia respiratória; Respiração artificial; Mecânica respiratória

ABSTRACT

Objective:

To evaluate the changes in ventilatory mechanics and hemodynamics that occur in patients dependent on mechanical ventilation who are subjected to a standard respiratory therapy protocol.

Methods:

This experimental and prospective study was performed in two intensive care units, in which patients dependent on mechanical ventilation for more than 48 hours were consecutively enrolled and subjected to an established respiratory physiotherapy protocol. Ventilatory variables (dynamic lung compliance, respiratory system resistance, tidal volume, peak inspiratory pressure, respiratory rate, and oxygen saturation) and hemodynamic variables (heart rate) were measured one hour before (T-1), immediately after (T0) and one hour after (T+1) applying the respiratory physiotherapy protocol.

Results:

During the period of data collection, 104 patients were included in the study. Regarding the ventilatory variables, an increase in dynamic lung compliance (T-1 = 52.3 ± 16.1mL/cmH2O versus T0 = 65.1 ± 19.1mL/cmH2O; p < 0.001), tidal volume (T-1 = 550 ± 134mL versus T0 = 698 ± 155mL; p < 0.001), and peripheral oxygen saturation (T-1 = 96.5 ± 2.29% versus T0 = 98.2 ± 1.62%; p < 0.001) were observed, in addition to a reduction of respiratory system resistance (T-1 = 14.2 ± 4.63cmH2O/L/s versus T0 = 11.0 ± 3.43cmH2O/L/s; p < 0.001), after applying the respiratory physiotherapy protocol. All changes were present in the assessment performed one hour (T+1) after the application of the respiratory physiotherapy protocol. Regarding the hemodynamic variables, an immediate increase in the heart rate after application of the protocol was observed, but that increase was not maintained (T-1 = 88.9 ± 18.7 bpm versus T0 = 93.7 ± 19.2bpm versus T+1 = 88.5 ± 17.1bpm; p < 0.001).

Conclusion:

Respiratory therapy leads to immediate changes in the lung mechanics and hemodynamics of mechanical ventilation-dependent patients, and ventilatory changes are likely to remain for at least one hour.

Respiratory therapy; Respiration, artificial; Respiratory mechanics

INTRODUCTION

Ventilatory support is provided to patients with acute respiratory failure to provide rest for the respiratory muscles and reduce the work of breathing until the acute condition is resolved. The mobilization and removal of respiratory secretions plays a key role in improving bronchial hygiene and gas exchange and in reducing the work of breathing, thus changing the mechanics of critically ill patients subjected to invasive ventilatory support.(1Stiller K. Physiotherapy in intensive care: towards and evidence-based practice. Chest. 2000;118(6):1801-13. Review.)

In most intensive care units (ICUs), respiratory physiotherapy is an integral part of the management of critically ill patients who require invasive ventilatory support. Respiratory physiotherapy techniques include postural drainage (PD), mobilization, vibration, percussion, manual hyperinflation (MH), and aspiration of the airways.(2Imle PC. Percussão e vibração. In: Mackenzie CF, Ciesla N, Imle PC, Klemic N. Fisioterapia respiratória em unidade de terapia intensiva. São Paulo: Panamericana; 1998. p. 89-98.) The routine combination of these techniques primarily aims to prevent complications such as tracheal prosthesis obstruction, ventilator-associated pneumonia (VAP), and patient-ventilator asynchrony.(3David CM, Machado M, Vianna A, Marinho JM. Complicações da ventilação mecânica. J Pneumol. 2000;26(Supl 2):45-54.

Guglielminotti J, Desmonts JM, Dureuil B. Effects of tracheal suctioning on respiratory resistances in mechanically ventilated patients. Chest. 1998;113(5):1335-8.

Barker M, Adams S. An evaluation of a single chest physiotherapy treatment on mechanically ventilated patients with acute lung injury. Physiother Res Int. 2002;7(3):157-69.

Denehy L. The use of manual hyperinflation in airway clearance. Eur Respir J. 1999;14(4):958-65. Review.

Unoki T, Mizutani T, Toyooka H. Effects of expiratory rib cage compression and/or prone position on oxygenation and ventilation in mechanically ventilated rabbits with induced atelectasis. Respir Care. 2003;48(8):754-62.

Berney S, Denehy L. A comparison of the effects of manual and ventilator hyperinventilator hyperinflation on static lung compliance and sputum production in intubated and ventilated intensive care patients. Physiother Res Int. 2002;7(2):100-8.

Hodgson C, Denehy L, Ntoumenopoulos G, Santamaria J, Carroll S. An investigation of the early effects of manual lung hyperinflation in critically ill patients. Anaesth Intensive Care. 2000;28(3):255-61.

10 Berney S, Denehy L, Pretto J. Head-down tilt and manual hyperinflation enhance sputum clearance in patients who are intubated and ventilated. Austr J Physiother. 2004;50(1):9-14.

11 Paratz J, Lipman J, McAuliffe M. Effect of manual hyperinflation on hemodynamics, gas exchange, and respiratory mechanics in ventilated patients. J Intensive Care Med. 2002;17(6):317-24.

12 Unoki T, Kawasaki Y, Mizutani T, Fujino Y, Yanagisawa Y, Ishimatsu S, et al. Effects of expiratory rib-cage compressionon oxigenatuion, ventilation, and airway-secretion removal in patients receiving mechanical ventilation. Respir Care. 2005;50(11):1430-7.

13 AARC Clinical Practice Guideline. Endotracheal suctioning of mechanically ventilated adults and children with artificial airways. American Association for Respiratory Care. Respir Care. 1993;38(5):500-4.
-1414 Fink JB. Positive pressure techniques for airway clearance. Respir Care. 2002;47(7):786-96.)

Numerous respiratory therapy protocols have been described for the care of mechanical ventilation (MV)-dependent patients, but with conflicting results.(1010 Berney S, Denehy L, Pretto J. Head-down tilt and manual hyperinflation enhance sputum clearance in patients who are intubated and ventilated. Austr J Physiother. 2004;50(1):9-14.

11 Paratz J, Lipman J, McAuliffe M. Effect of manual hyperinflation on hemodynamics, gas exchange, and respiratory mechanics in ventilated patients. J Intensive Care Med. 2002;17(6):317-24.
-1212 Unoki T, Kawasaki Y, Mizutani T, Fujino Y, Yanagisawa Y, Ishimatsu S, et al. Effects of expiratory rib-cage compressionon oxigenatuion, ventilation, and airway-secretion removal in patients receiving mechanical ventilation. Respir Care. 2005;50(11):1430-7.,1515 Choi JS, Jones AY. Effects of manual hyperinfl ation and suctioning in respiratory mechanics in mechanically ventilated patients with ventilator-associated pneumonia. Aust J Physiother. 2005;51(1):25-30.,1616 Mackenzie CF, Shin B. Cardiorespiratory function before and after chest physiotherapy in mechanically ventilated patients with post-traumatic respiratory failure. Crit Care Med. 1985;13(6):483-6.) The aim of this study was to evaluate the changes in ventilatory mechanics and hemodynamics that occur in MV-dependent patients undergoing a standard respiratory physiotherapy protocol.

METHODS

This was an experimental and prospective study conducted at two mixed ICUs: the Intensive Care Center of the Hospital Moinhos de Vento in Porto Alegre and the ICU of the Hospital de Pronto-Socorrode Canoas in Canoas, both in the state of Rio Grande do Sul. The study was approved by the Research Ethics Committees of both hospitals (Project no. 2004/18 and 05-407, respectively), and patients and close family members participated in the study after signing an informed consent form.

All patients dependent on MV for ≥ 48 hours and who were prescribed respiratory physiotherapy during the period from February to September 2014 were consecutively included in the study after signing the informed consent form. The exclusion criteria consisted of patients with hemodynamic instability (change in vasopressor dose in the last two hours, mean blood pressure ≥ 120mmHg or ≤ 60mmHg, heart rate (HR) ≥ 130bpm or ≤ 50bpm, and the presence of serious ventricular arrhythmias); patients with ventilatory instability, i.e., the need for a fraction of inspired oxygen (FiO2) ≥ 0.8 or the need for positive end-expiratory pressure (PEEP) ≥ 15cmH2O; dying patients (as defined by the medical staff); patients with radiological evidence of fracture of two or more ribs; and patients with severe bronchospasms.

Respiratory physiotherapy protocol

The following protocol was applied to all patients. First, the use of inhaled or intravenous bronchodilators, as well as changes in the MV parameters 120 minutes before and after respiratory physiotherapy care, were not allowed. Then, chest compression-vibrations were performed for five minutes in right lateral decubitus and five minutes in the left lateral decubitus. This technique consists of manually compressing the chest during expiration and releasing the compression at the end of expiration, facilitating active inspiration to mobilize pulmonary secretions and improve alveolar ventilation. Next, manual hyperinflation (MH) was performed by the instillation of 10ml of saline solution (0.9% saline) in the endotracheal tube and the use of a manual resuscitation bag for one minute, followed by aspiration of bronchial secretions for a maximum of 15 seconds. Finally, the patient was placed in a 30º-decubitus position.

Data collected

All patients were mechanically ventilated using Savina®, Evita-2®, or Evita-4® ventilators (Drager, Lübek, Germany) with the capacity to analyze the pressure, flow, and volume curves. The ventilatory variables collected consisted of the ventilation mode, dynamic lung compliance (Cdyn), respiratory system resistance (Rsr) in patients receiving constant-flow, volume-controlled ventilation, tidal volume (VT), peak inspiratory pressure (PIP), and PEEP. The hemodynamic and oxygenation variables continuously recorded by the multiparameter monitors (Siemens SC 7000® and SC 9000® (Siemens, Sweden)) consisted of the heart rate, respiratory rate (RR), and peripheral oxygen saturation (SpO2). All data were collected at three timepoints relative to the application of the respiratory physiotherapy protocol: (a) pre-protocol - the variables were analyzed one hour before applying the respiratory physiotherapy protocol (T-1); immediate post-protocol - immediately after applying the respiratory physiotherapy protocol (T0); and (c) late post-protocol - one hour after applying the respiratory therapy protocol (T+1). Pulmonary radiological data from the ICU admission day (radiologist report), the causes of acute respiratory failure, preexisting conditions, and MV parameters, as well as demographic data, were also acquired.

Statistical analysis

A descriptive analysis of the data was conducted using the means and standard deviations for quantitative variables (or medians and interquartile ranges), while categorical variables were expressed as frequencies and percentages. The Kolmogorov-Smirnov test was used to verify the normal distribution of the data. In the inferential analysis, to assess the variation among the three measurements performed on the same patient, the ANOVA test for repeated measures was used with Bonferroni multiple comparisons to identify potential differences between the assessment timepoints. Statistical Package for the Social Sciences (SPSS) 12.0 was used for data analysis, and the significance level was set at 5%.

RESULTS

During data collection, 104 patients were included in the study. Each patient was included only once in the analysis. The mean age of patients was 53 ± 22 years, and the main causes of respiratory failure were multiple trauma (26.9%) and traumatic brain injury (22.1%), as shown in table 1.

Table 1
Sample characterization

Table 2 shows an increase in the Cdyn, VT, RR, and SpO2, and a decrease in the Rsr immediately after applying the respiratory physiotherapy protocol. The changes observed remained during the assessment performed one hour after the end of the respiratory therapy protocol. An immediate increase in the heart rate, which was not sustained, is shown in table 2.

Table 2
Behavior of ventilatory and hemodynamic variables at the three assessment timepoints, i.e., one hour before (T-1) and immediately (T0) and one hour after (T+1) application of the respiratory therapy protocol

DISCUSSION

The findings of this study suggest that, in MV-dependent patients, significant hemodynamic and ventilatory changes occur immediately after respiratory therapy; however, only the ventilatory changes persisted for at least one hour.

Respiratory therapy is part of the multidisciplinary care of critically ill patients dependent on MV because pulmonary complications resulting from the depression of the cough reflex, reduction in mucociliary clearance, and increase in bronchial mucus production can lead to the retention of bronchial secretions, atelectasis formation, and the development of nosocomial pneumonia.(2Imle PC. Percussão e vibração. In: Mackenzie CF, Ciesla N, Imle PC, Klemic N. Fisioterapia respiratória em unidade de terapia intensiva. São Paulo: Panamericana; 1998. p. 89-98.

David CM, Machado M, Vianna A, Marinho JM. Complicações da ventilação mecânica. J Pneumol. 2000;26(Supl 2):45-54.

Guglielminotti J, Desmonts JM, Dureuil B. Effects of tracheal suctioning on respiratory resistances in mechanically ventilated patients. Chest. 1998;113(5):1335-8.
-5Barker M, Adams S. An evaluation of a single chest physiotherapy treatment on mechanically ventilated patients with acute lung injury. Physiother Res Int. 2002;7(3):157-69.,1717 Clini E, Ambrosino N. Early physiotherapy in the respiratory intensive care unit. Respir Med. 2005;99(9):1096-104.) Particularly in intubated, sedated, and MV-dependent patients, respiratory therapy techniques facilitate the mobilization and elimination of bronchial secretions.(1Stiller K. Physiotherapy in intensive care: towards and evidence-based practice. Chest. 2000;118(6):1801-13. Review.

Imle PC. Percussão e vibração. In: Mackenzie CF, Ciesla N, Imle PC, Klemic N. Fisioterapia respiratória em unidade de terapia intensiva. São Paulo: Panamericana; 1998. p. 89-98.
-3David CM, Machado M, Vianna A, Marinho JM. Complicações da ventilação mecânica. J Pneumol. 2000;26(Supl 2):45-54.,1818 Rosa FK, Roese CA, Savi A, Dias AS, Monteiro MB. Comportamento da mecânica pulmonar após a aplicação de protocolo de fisioterapia respiratória e aspiração traqueal em pacientes com ventilação mecânica invasiva. Rev Bras Ter Intensiva. 2007;19(2):170-5.)

Respiratory physiotherapy techniques consist of manual, postural, and kinetic techniques.(1Stiller K. Physiotherapy in intensive care: towards and evidence-based practice. Chest. 2000;118(6):1801-13. Review.,2Imle PC. Percussão e vibração. In: Mackenzie CF, Ciesla N, Imle PC, Klemic N. Fisioterapia respiratória em unidade de terapia intensiva. São Paulo: Panamericana; 1998. p. 89-98.) Conventional techniques include PD, chest compression-vibrations, manual chest compression, MH, tracheal aspiration (TA), and cough stimulation.(2Imle PC. Percussão e vibração. In: Mackenzie CF, Ciesla N, Imle PC, Klemic N. Fisioterapia respiratória em unidade de terapia intensiva. São Paulo: Panamericana; 1998. p. 89-98.) As for the PD, the positioning in bed helps to improve the V/Q ratio, increase lung volume, reduce the work of breathing, minimize myocardial work, and mobilize and remove secretions from the airway with the help of gravity.(7Unoki T, Mizutani T, Toyooka H. Effects of expiratory rib cage compression and/or prone position on oxygenation and ventilation in mechanically ventilated rabbits with induced atelectasis. Respir Care. 2003;48(8):754-62.) Manual chest compression provides an expansion of collapsed lung areas, thus improving the V/Q ratio, in addition to acting as a facilitating stimulus of thoracic mobility, which can be decreased.(1212 Unoki T, Kawasaki Y, Mizutani T, Fujino Y, Yanagisawa Y, Ishimatsu S, et al. Effects of expiratory rib-cage compressionon oxigenatuion, ventilation, and airway-secretion removal in patients receiving mechanical ventilation. Respir Care. 2005;50(11):1430-7.) The chest compression-vibrations applied to the expiratory phase of the respiratory cycle allow better lung emptying, thus facilitating bronchial hygiene.(2Imle PC. Percussão e vibração. In: Mackenzie CF, Ciesla N, Imle PC, Klemic N. Fisioterapia respiratória em unidade de terapia intensiva. São Paulo: Panamericana; 1998. p. 89-98.,6Denehy L. The use of manual hyperinflation in airway clearance. Eur Respir J. 1999;14(4):958-65. Review.) MH favors the displacement of accumulated secretions in the airways and reduces pulmonary shunting.(6Denehy L. The use of manual hyperinflation in airway clearance. Eur Respir J. 1999;14(4):958-65. Review.,8Berney S, Denehy L. A comparison of the effects of manual and ventilator hyperinventilator hyperinflation on static lung compliance and sputum production in intubated and ventilated intensive care patients. Physiother Res Int. 2002;7(2):100-8.

Hodgson C, Denehy L, Ntoumenopoulos G, Santamaria J, Carroll S. An investigation of the early effects of manual lung hyperinflation in critically ill patients. Anaesth Intensive Care. 2000;28(3):255-61.

10 Berney S, Denehy L, Pretto J. Head-down tilt and manual hyperinflation enhance sputum clearance in patients who are intubated and ventilated. Austr J Physiother. 2004;50(1):9-14.

11 Paratz J, Lipman J, McAuliffe M. Effect of manual hyperinflation on hemodynamics, gas exchange, and respiratory mechanics in ventilated patients. J Intensive Care Med. 2002;17(6):317-24.

12 Unoki T, Kawasaki Y, Mizutani T, Fujino Y, Yanagisawa Y, Ishimatsu S, et al. Effects of expiratory rib-cage compressionon oxigenatuion, ventilation, and airway-secretion removal in patients receiving mechanical ventilation. Respir Care. 2005;50(11):1430-7.

13 AARC Clinical Practice Guideline. Endotracheal suctioning of mechanically ventilated adults and children with artificial airways. American Association for Respiratory Care. Respir Care. 1993;38(5):500-4.

14 Fink JB. Positive pressure techniques for airway clearance. Respir Care. 2002;47(7):786-96.

15 Choi JS, Jones AY. Effects of manual hyperinfl ation and suctioning in respiratory mechanics in mechanically ventilated patients with ventilator-associated pneumonia. Aust J Physiother. 2005;51(1):25-30.

16 Mackenzie CF, Shin B. Cardiorespiratory function before and after chest physiotherapy in mechanically ventilated patients with post-traumatic respiratory failure. Crit Care Med. 1985;13(6):483-6.

17 Clini E, Ambrosino N. Early physiotherapy in the respiratory intensive care unit. Respir Med. 2005;99(9):1096-104.

18 Rosa FK, Roese CA, Savi A, Dias AS, Monteiro MB. Comportamento da mecânica pulmonar após a aplicação de protocolo de fisioterapia respiratória e aspiração traqueal em pacientes com ventilação mecânica invasiva. Rev Bras Ter Intensiva. 2007;19(2):170-5.
-1919 Maa SH, Hung TJ, Hsu KH, Hsieh YI, Wang KY, Wang CH, et al. Manual hyperinflation improves alveolar recruitment in difficult-to-wean patients. Chest. 2005;128(4):2714-21.) This technique, performed on patients with spontaneous ventilation, aims to prevent alveolar collapse, expand collapsed alveoli, improve oxygenation and lung compliance, and minimize the risk of hypoxemia, as well as stimulate coughing in MV-dependent patients.(9Hodgson C, Denehy L, Ntoumenopoulos G, Santamaria J, Carroll S. An investigation of the early effects of manual lung hyperinflation in critically ill patients. Anaesth Intensive Care. 2000;28(3):255-61.,1111 Paratz J, Lipman J, McAuliffe M. Effect of manual hyperinflation on hemodynamics, gas exchange, and respiratory mechanics in ventilated patients. J Intensive Care Med. 2002;17(6):317-24.,1212 Unoki T, Kawasaki Y, Mizutani T, Fujino Y, Yanagisawa Y, Ishimatsu S, et al. Effects of expiratory rib-cage compressionon oxigenatuion, ventilation, and airway-secretion removal in patients receiving mechanical ventilation. Respir Care. 2005;50(11):1430-7.) Our study protocol utilized the application of two physiotherapy techniques (manual chest compression and MH).

Although most authors compare those techniques alone, protocols combining different techniques are part of the physiotherapy practice in the ICU and have a primary goal of the removal of respiratory secretions. Fink(1414 Fink JB. Positive pressure techniques for airway clearance. Respir Care. 2002;47(7):786-96.) studied the alternate application of the techniques TA, PD, and chest percussion and observed improved SpO2 and airway resistance (Raw) in all sessions performed in the four days of the study. Mackenzie et al.(1616 Mackenzie CF, Shin B. Cardiorespiratory function before and after chest physiotherapy in mechanically ventilated patients with post-traumatic respiratory failure. Crit Care Med. 1985;13(6):483-6.) applied manual chest techniques in 19 patients and found increased Cdyn up to two hours after finishing the application of the maneuver. In our study, the increase in SpO2 and Cdyn and decrease in Raw started immediately after applying the protocol and were sustained for the next hour. However, the changes in the pulmonary mechanics did not exceed 30 minutes.(8Berney S, Denehy L. A comparison of the effects of manual and ventilator hyperinventilator hyperinflation on static lung compliance and sputum production in intubated and ventilated intensive care patients. Physiother Res Int. 2002;7(2):100-8.,1010 Berney S, Denehy L, Pretto J. Head-down tilt and manual hyperinflation enhance sputum clearance in patients who are intubated and ventilated. Austr J Physiother. 2004;50(1):9-14.)

Regarding the changes in the oxygenation indices, Barker and Adams(5Barker M, Adams S. An evaluation of a single chest physiotherapy treatment on mechanically ventilated patients with acute lung injury. Physiother Res Int. 2002;7(3):157-69.) showed no differences in oxygenation (PaO2) or alveolar ventilation (PaCO2) in 17 patients with acute respiratory distress syndrome when comparing three treatment protocols: TA, TA + PD, and TA + PD + MH. In our patients, SpO2 measurements showed improved oxygenation immediately after applying the respiratory physiotherapy protocol, which lasted at least one hour. Other authors(2020 Clarke RC, Kelly BE, Convery PN, Fee JP. Ventilatory characteristics in mechanically ventilated patients during manual hyperventilation for chest physiotherapy. Anaesthesia. 1999;54(10):936-40.,2121 Ciesla ND. Chest physical therapy for patients in the intensive care unit. Phys Ther. 1996;76(6):609-25.) have found similar results of improved oxygenation, however, with shorter duration.

Few studies(2020 Clarke RC, Kelly BE, Convery PN, Fee JP. Ventilatory characteristics in mechanically ventilated patients during manual hyperventilation for chest physiotherapy. Anaesthesia. 1999;54(10):936-40.) have evaluated the changes in PIP during and after physiotherapy treatment. Our data showed a persistent reduction of PIP after completion of the protocol.

In a study of difficult-to-wean patients, Hodgson et al.(9Hodgson C, Denehy L, Ntoumenopoulos G, Santamaria J, Carroll S. An investigation of the early effects of manual lung hyperinflation in critically ill patients. Anaesth Intensive Care. 2000;28(3):255-61.) and Maa et al.,(1919 Maa SH, Hung TJ, Hsu KH, Hsieh YI, Wang KY, Wang CH, et al. Manual hyperinflation improves alveolar recruitment in difficult-to-wean patients. Chest. 2005;128(4):2714-21.), in 18 and 23 patients, respectively, showed improvement of static lung compliance (Cstat) in the group that underwent MH. Choi and Jones(1515 Choi JS, Jones AY. Effects of manual hyperinfl ation and suctioning in respiratory mechanics in mechanically ventilated patients with ventilator-associated pneumonia. Aust J Physiother. 2005;51(1):25-30.) confirmed that a physiotherapy protocol (MH + TA) could increase Cstat and decrease Rsr for at least 30 minutes. In our study, which included the evaluation of patients who were receiving pressure support ventilation (PSV), the chest compliance changes were demonstrated by measuring the Cdyn.

Regarding techniques for tracheal secretion removal, a protocol consisting of MH + PD + TA increased the amount (weight) of mucus removed.(9Hodgson C, Denehy L, Ntoumenopoulos G, Santamaria J, Carroll S. An investigation of the early effects of manual lung hyperinflation in critically ill patients. Anaesth Intensive Care. 2000;28(3):255-61.,2323 Ntoumenopoulos G, Presneill JJ, McElholum M, Cade JF. Chest physiotherapy for the prevention of ventilator-associated pneumonia. Intensive Care Med. 2002;28(7):850-6.) Mackenzie et al.(1616 Mackenzie CF, Shin B. Cardiorespiratory function before and after chest physiotherapy in mechanically ventilated patients with post-traumatic respiratory failure. Crit Care Med. 1985;13(6):483-6.) showed that after completion of a bronchial hygiene protocol, a reduction of 20% in the intrapulmonary shunt, an increase of Cdyn by 14%, and an improvement of gas exchange within two hours after physiotherapy were observed. Hodgson et al.(9Hodgson C, Denehy L, Ntoumenopoulos G, Santamaria J, Carroll S. An investigation of the early effects of manual lung hyperinflation in critically ill patients. Anaesth Intensive Care. 2000;28(3):255-61.) showed an increased removal of respiratory secretions and an increase of 30% of Cdyn after the use of MH, compared to TA alone, in 18 mechanically ventilated patients. Unoki et al.(1212 Unoki T, Kawasaki Y, Mizutani T, Fujino Y, Yanagisawa Y, Ishimatsu S, et al. Effects of expiratory rib-cage compressionon oxigenatuion, ventilation, and airway-secretion removal in patients receiving mechanical ventilation. Respir Care. 2005;50(11):1430-7.) found no differences when comparing those two techniques in 31 mechanically ventilated patients. Stiller et al.(2222 Stiller K, Geake T, Taylor J, Grant R, Hall B. Acute lobar atelectasis. A comparison of two chest physioteraphy regimens. Chest. 1990;98(6):1336-40.) found greater efficacy in the resolution of atelectasis and improvement in oxygenation when using a protocol that combined PD, chest compression-vibrations, MH, and TA compared with a protocol consisting of MH and TA.

Regarding the changes in hemodynamics, Hodgson et al.(9Hodgson C, Denehy L, Ntoumenopoulos G, Santamaria J, Carroll S. An investigation of the early effects of manual lung hyperinflation in critically ill patients. Anaesth Intensive Care. 2000;28(3):255-61.) and Paratz et al.(1111 Paratz J, Lipman J, McAuliffe M. Effect of manual hyperinflation on hemodynamics, gas exchange, and respiratory mechanics in ventilated patients. J Intensive Care Med. 2002;17(6):317-24.) showed a 10% decrease in the mean blood pressure when MH techniques were applied, but no changes in the heart rate were observed, which contradicts our findings.

Ntoumenopulos et al.(2323 Ntoumenopoulos G, Presneill JJ, McElholum M, Cade JF. Chest physiotherapy for the prevention of ventilator-associated pneumonia. Intensive Care Med. 2002;28(7):850-6.) evaluated the clinical effectiveness of respiratory physiotherapy in the prevention of pneumonia in 60 MV-dependent patients. Patients undergoing the physiotherapy protocol had a lower incidence of pneumonia (39% versus 8%; p = 0.02), but this study did not evaluate the physiological effects of the techniques. Therefore, it is unclear whether the improvement of respiratory mechanics provided by the respiratory physiotherapy, as demonstrated in our study and in previous reports, is the cause of clinical improvement or is only associated with improvement (e.g., VAP). Our study was not designed with that purpose in mind and does not have a sufficient sample power to evaluate relevant clinical outcomes (e.g., complications or death), but it was able to demonstrate the ventilatory and hemodynamic changes triggered by a physiotherapy session and how long such changes last. We also emphasize other limitations of this study, including (a) measurement of the variables only in the first 60 minutes, which did not allow determination of the duration of the changes in ventilatory mechanics; (b) the use of one physiotherapy treatment protocol, which did not allow individualized assessment of each protocol technique; and (c) the heterogeneity of the sample studied (e.g., evaluation of patients under different ventilation conditions), which did not allow evaluation according to the ventilation mode used or the cause of respiratory failure (hypoxemic versus hypercapnic patients), among others.

CONCLUSION

The physiotherapy protocol applied was effective in improving the respiratory mechanics of patients dependent on mechanical ventilation. It is worth noting that these effects were measured after 60 minutes and remained present in most patients.

  • Responsible editor: Carmen Valente Barbas

References

  • 1
    Stiller K. Physiotherapy in intensive care: towards and evidence-based practice. Chest. 2000;118(6):1801-13. Review.
  • 2
    Imle PC. Percussão e vibração. In: Mackenzie CF, Ciesla N, Imle PC, Klemic N. Fisioterapia respiratória em unidade de terapia intensiva. São Paulo: Panamericana; 1998. p. 89-98.
  • 3
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Publication Dates

  • Publication in this collection
    Apr-Jun 2015

History

  • Received
    15 Dec 2014
  • Accepted
    20 May 2015
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