|Year : 2020 | Volume
| Issue : 2 | Page : 70-73
A study on the effect of manual hyperinflation on oxygenation and hemodynamic parameters in mechanically ventilated patients after valve replacement surgery
Srijani Banerjee1, Anjali Suresh2
1 Department of Physiotherapy, The Neotia University, Sarisa, West Bengal, India
2 Department of Physiotherapy, School of Health Sciences, Garden City University, Bengaluru, Karnataka, India
|Date of Submission||22-May-2020|
|Date of Decision||19-Aug-2020|
|Date of Acceptance||11-Oct-2020|
|Date of Web Publication||31-Dec-2020|
Dr. Srijani Banerjee
43, Shibtala Street, Uttarpara - 712 258, West Bengal
Source of Support: None, Conflict of Interest: None
BACKGROUND: Valve replacement surgeries being a major surgery require general anesthesia. Patients are kept on mechanical ventilation postoperatively which can cause some major dysfunctions of the respiratory and circulatory systems of the human body. Manual hyperinflation (MHI) is a technique that provides a tidal volume greater than the baseline volume and produces a turbulent flow that brings benefits such as improvement of static compliance of the respiratory system, increased oxygenation, mobilization of secretions, and recruitment of collapsed areas of the lung.
OBJECTIVES: The aim of this study was to compare the effectiveness of MHI in valve replacement patients on mechanical ventilation in terms of SpO2, heart rate (HR), respiratory rate (RR), blood pressure (BP), mean arterial pressure (MAP), and rate pressure product (RPP).
MATERIALS AND METHODS: Thirty cardiothoracic intensive care unit patients who were intubated and mechanically ventilated after valve replacement surgery were given 3–4 MHI breaths with an O2 flow rate of 15 L/min for 6–8 sets or till secretions were heard. Means of the pretreatment and posttreatment values were calculated and compared by the paired t-test.
Results: The results from the statistical analysis show that SpO2 remained almost same (P = 0.499). However, heart rate increased significantly (P = 0.048) after MHI. There was no adverse change in RPP (P = 0.409), but BP (P = 0.00 and 0.006), RR (P = 0.000), and MAP decreased significantly (P = 0.0005).
CONCLUSION: The MHI technique seems to promote more improvement in hemodynamic parameters than in oxygenation.
Keywords: Blood pressure, cardiac valve replacement, hyperinflation, mechanical ventilation, rate pressure product
|How to cite this article:|
Banerjee S, Suresh A. A study on the effect of manual hyperinflation on oxygenation and hemodynamic parameters in mechanically ventilated patients after valve replacement surgery. Physiother - J Indian Assoc Physiother 2020;14:70-3
|How to cite this URL:|
Banerjee S, Suresh A. A study on the effect of manual hyperinflation on oxygenation and hemodynamic parameters in mechanically ventilated patients after valve replacement surgery. Physiother - J Indian Assoc Physiother [serial online] 2020 [cited 2021 Jan 19];14:70-3. Available from: https://www.pjiap.org/text.asp?2020/14/2/70/305839
| Introduction|| |
Cardiac surgical procedures are associated with a high incidence (17%–88%) of postoperative complications. Postoperative pulmonary complications among patients undergoing cardiac surgery contribute to longer stay in intensive care and increase mortality in hospital.,
Surgery for valvular heart disease has undergone important refinements during the past several years. At the same time, it has also paved way for some other major dysfunctions of the respiratory and circulatory systems of the human body. All patients of valve replacement surgery require mechanical ventilation. However, patients receiving mechanical ventilation may have an increased risk of sputum retention, atelectasis, and pneumonia, making ventilation weaning more difficult and resulting in excess morbidity and mortality.,
Patients with valvular diseases also present with respiratory symptoms hence making them more prone for post-surgical complications. These complications can be avoided and prevented with early and proper chest physiotherapy intervention.
Several chest physiotherapy techniques have been used with mechanically-ventilated patients. However, patients who undergo thoracic or cardiac surgery have anterior or lateral incisions, as well as bone fractures and instability of the sternum and ribs, which limit the application of some manual techniques.
Manual hyperinflation (MHI) is a technique that provides a tidal volume greater than the baseline volume and produces a turbulent flow that brings benefits such as improvement of static compliance of the respiratory system, increased oxygenation, mobilization of secretions, and recruitment of collapsed areas of the lung. It is usually used as amelioration to other physiotherapy techniques or only when other techniques of secretion clearance such as postural drainage, percussion, and vibration are not sufficient or effective. However, the efficacy of MHI when given in isolation is not clearly established. The effect of MHI with respect to the clearance of excess and thick secretion and lung compliance has been well established, but there is limited evidence of the effect of MHI on oxygen saturation and hemodynamics in post-valve replacement surgery patients who are on mechanical ventilation. Despite massive research MHI still remains a very controversial and oft a misjudged technique owing to the complications that might arise when not given with care. The effect of MHI on the postsurgical ventilated patients gets overshadowed when given alongside other chest physiotherapy techniques.
This study attempts to define the efficacy of MHI as an isolated physiotherapy maneuver and its effect on the oxygen saturation and hemodynamics of valve replacement surgery patients on mechanical ventilator support. The outcome of this study could yield greater understanding in the relevant importance of MHI in intensive care units (ICUs) and may prove to be useful in treating patients which might improve the gaseous exchange and reduce the ill-effects of mechanical ventilators.
| Materials and Methods|| |
After getting the formal consent from the ethical committee of the concerned institutions, 30 mechanically ventilated postsurgical valve replacement surgery patients who fulfilled the inclusion criteria and had given informed consent were selected into one single group. All the participants had been informed about the study preoperatively, and a prior consent was obtained from them before the surgery and before commencing the study.
Those who were excluded were as follows: (1) patients with unstable BP, (2) patients with arrhythmias, (3) hemoptysis, (4) high risk/critically ill patients, (5) undrained pneumothorax, (6) patients with neurological disorders, (7) patients with traumatic injuries, and (8) patients with chest deformity.
The MHI was given using the Laerdal circuit in the following manner – the patient was positioned to supine lying. The vital signs of the patients were checked first. The necessary data (positive end-expiratory pressure [PEEP], tidal volume, and peak airway pressure) were noted from the ventilator. The bagging circuit was then connected to the oxygen supply and the flow rate was set at 15 L/min. The patient was removed from the ventilator circuit and connected to the bagging circuit. Few normal tidal breaths were given to the patient to understand the compliance of the patient's lungs. Then the subjects were given 3–4 hyperinflation followed by tidal volume breaths. The MHI technique was given in three phases. A slow inspiration was given followed by inspiratory hold phase of 2–3 s. The bag was then rapidly released for forceful expiration. This was continued till secretions were heard or for 6–8 sets and after that suctioning was done. Apart from the above-mentioned procedure, no other physiotherapy technique was added. This was done to understand the effect of MHI in isolation.
The heart rate (HR), blood pressure (BP), respiratory rate (RR) and the SpO2 were recorded from the MEC – 2000 Mindray ICU Monitor. The mean arterial pressure (MAP) and rate pressure product (RPP) were calculated manually. The first set of readings of the above parameters for the selected participants was recorded from the monitor before giving any physiotherapy. The second set of readings was taken after the MHI was done.
The two sets of data were compared. They were analyzed using the standard method in Microsoft Excel. The data were expressed in terms of mean and standard deviation which was calculated and compared by the paired t-test.
| Results|| |
Thirty patients, which included 24 female (80%) and 6 male patients (20%) who met the inclusion criteria were included in the study. Demographic data for the patients and data from the ventilator are shown in [Table 1].
Out of 30 patients, 16 underwent mitral valve replacement, 6 had aortic valve replacement, 6 had double valve replacement, and 4 patients underwent pulmonary valve replacement.
The results as seen in [Table 2], can be summarized as follows: On comparing the recorded values, it was found most of the parameters underwent significant change after MHI. There was a significant increase in the HR (P = 0.048) after MHI. The mean HR increased from 108.73 ± 18.55 to 120.23 ± 18.93. The change in BP was also found to be significant for both systolic and diastolic BP (P = 0.00 and 0.006, respectively). As opposed to the HR, the systolic BP decreased to 110.26 ± 13.33 from a preintervention mean of 124.66 ± 16.66 and the diastolic BP decreased from 69.56 ± 10.54 to 61.7 ± 9.12.
|Table 2: Comparative data for the dependent variables for the patients (mean±standard deviation)|
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In case of RR, the postintervention values were lower than the preintervention values, the mean values being 21.6 ± 6.85 and 18.3 ± 7.39, respectively. The decrease in RR was found to be statistically significant (P = 0.000). Contrary to this, no significant difference was found in SpO2 (P = 0.499). The mean values before and after MHI are 97.53 ± 3.45 and 98.83 ± 2.50, respectively. Even though there was increase in SpO2 after MHI, it was not statistically significant.
There was a significant difference between the preintervention and postintervention values of MAP (P = 0.0005). The mean value before MHI is 87.86 ± 11.32 and after MHI, the mean value is 77.81 ± 9.19. The RPP did not change significantly (P = 0.409). The preintervention and postintervention mean for RPP was 13.40 ± 2.12 and 13.22 ± 2.49, respectively.
The mean and standard deviation is presented in the tables and figures. Comparison of the preintervention and postintervention values of each outcome measure is done using the paired t-test and the P value inference is done.
| Discussion|| |
This retrospective study deals with patients in the acute phase of their surgery, i.e., postoperative day “1;” therefore, there was a major contribution of anesthesia to abnormalities of gaseous exchange. The patients studied were representatives of a cardiothoracic ICU (CTICU) population who were on synchronized intermittent mechanical ventilation mode of ventilation to assist with their extubation. The parameters of the ventilator were based on the protective ventilator settings consisting of tidal volume of approximately 6 ml/kg, PEEP of 6–12 cm H2O, and recruitment maneuvers that decrease the development of acute respiratory distress syndrome, pulmonary infection, and atelectasis.
The samples were selected according to the convenient sampling. All patients were selected preoperatively and then assessed postoperatively. Out of the selected patients, three patients could not be included in the study due to various factors such as arrhythmia and unstable BP in two patients and self-extubation in one case. Three other patients who fulfilled the inclusion criteria and were willing to participate were included.
The MHI was administered using the Laerdal circuit, and the protocol in this study was based on the works of L. Denehy, S. Berney, and J. A. Pryor. The technique was in three phases – slow inspiration, 2–3 s inspiratory hold, and forceful expiration. O2 was kept at 15 L/min. 3–4 hyperinflations were given for a set of 6–8 times or till secretions were heard.
The tidal volume applied in MHI is aimed to be a volume which is approximately 150–200 percent greater than the tidal volume delivered by a mechanical ventilator and two to three times the resting tidal volume of a normal subject. The peak airway pressures reach approximately 40 cm H2O. The two-handed technique using the Laerdal circuit is known to give the aimed tidal volume and “slow” inflation flow rates.,,
Consistent with the previous studies, the results of this study showed that even though there was an increase in SpO2 after MHI, the increase was not statistically significant with the P value at 0.499. Blattner et al. reported that patients on mechanical ventilation after myocardial re-vascularization had better oxygenation and static lung compliance after manual lung hyperinflation. A significant difference was seen in the systolic BP with P value of 0.000 and for diastolic BP the P value is 0.006. The MAP also underwent a significant change with a P value of 0.0005. This result was similar to the study by Pinheiro et al. who found significant difference in the systolic and diastolic BP before and after giving respiratory physiotherapy. A significant reduction of the MAP was also noted.
Klein et al. show that the RPP is frequently elevated by chest physiotherapy to a level which can lead to ischemia in cardiac patients. Jellema et al. show that even though MHI causes increments in respiratory parameters, it did not cause significant change in the hemodynamic parameters which returned to baseline in 15 min. Patman et al. further showed that even though MHI produced changes in HR, it was not of a magnitude that was considered to be clinically significant.
It is observed, that there is a slight decrease in the RPP, but not in a statistically significant way with the P value of 0.409. The HR was found to be significantly higher after MHI and the P value was 0.048. As opposed to HR, there was a decrease in RR, even though the change was statistically significant. This study reinforces the same.
With this experimental study, we conclude that manual lung hyperinflation when applied as a standalone technique is also effective in bringing significant improvement to the RR, BP and other hemodynamic parameters. We can also conclude that even though the oxygenation increased, it was not statistically significant. This study shows that MHI affects the hemodynamic and oxygen parameters similar to all the other chest physiotherapy technique.
We would like to acknowledge Dr. Kalpesh Mallik, Dr. Ranjan Sengupta, Dr. Sanjay Pandey and all the Nursing Staff of the Care Hospital and Fortis Hospital, Raipur, India, for referring their patients for the study. All of them have generously donated many hours of their valuable time. We take this opportunity to express our heartfelt gratitude to the patients who consented to participate in the study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]