http://www.banglajol.info/index.php/JNINB
Original Article
DOI: https://doi.org/10.3329/jninb.v7i2.58093
Journal of National Institute of Neurosciences Bangladesh,
ISSN (Online) 2518-6612
July 2021, Vol. 7, No. 2, pp. 92-96
ISSN (Print)
2410-8030
Comparison of Clinico-Demographic Characteristics and Rapid Shallow
Breathing Index of Patients on Mechanical Ventilation at Intensive Care Unit
Md. Sirajul Islam1, Uzzwal Kumar Mallick2, AKM Ferdous Rahman3,
Md. Gias Uddin4, Kazi Eshika Raka5
1
Assistant Professor, Department of Critical Care Medicine, National Institute of Neurosciences and Hospital, Dhaka,
Bangladesh; 2Registrar, Department of Critical Care Medicine, National Institute of Neurosciences and Hospital, Dhaka,
Bangladesh; 3Assistant Professor, Department of Anesthesia, Pain, Palliative and Intensive Care Unit, Dhaka Medical College
and Hospital, Dhaka, Bangladesh; 4Phase B residence, Anesthesiology, Department of Anesthesia, Pain, Palliative and
Intensive Care Unit, Dhaka Medical College and Hospital, Dhaka, Bangladesh; 5Lecturer, Department of Physiology, Care
Medical College, Dhaka, Bangladesh
[Received on: 22 April 2021; Accepted on: 12 May 2021; Published: 1 July 2021]
Abstract
Background: Mechanical ventilation (MV) is a life-saving intervention in the intensive care unit that should
be considered for patients with respiratory failure. Objective: The purpose of the present study was to
compare the clinico-demographic characteristics and rapid shallow breathing index of patients on mechanical
ventilation at intensive care unit. Methodology: This prospective cohort study was conducted in the
Department of Anesthesia, Pain Palliative & Intensive Care Unit of Dhaka Medical College Hospital, Dhaka,
Bangladesh from January 2014 to December 2015 for a period of two (2) years. Patients on mechanical
ventilation more than 48 hours with the age of 18 to 60 years after fulfilling the inclusion and exclusion
criteria were included as study population. One type of ventilator (eVent Medical) was used in all patients.
Primary and daily setting of ventilators and the decision to weaning of the patient was made by the ICU
consultants. The rapid shallow breathing index (RSBI) was measured by the ratio of respiratory frequency (f)
to average exhaled tidal volume (EVT). When rapid shallow breathing index was 105 breath/min/L or less
and more than 105 breath/min/L were taken as low and high RSBI respectively. Result: A total number of
117 patients were recruited for this study after fulfilling the inclusion and exclusion criteria of which 92
patients were in low RSBI group and the rest 25 patients were in high RSBI group. The mean age was found
31.8±12.8 years in low RSBI group and 35.9±13.2 years in high RSBI group (p>0.05). It was observed that
male was found 57(62.0%) in low RSBI group and 13(52.0%) in high RSBI group (p>0.05). It was observed
that 14(15.2%) patients had laparotomy in low RSBI group and 4(16.0%) in high RSBI group (p>0.05).
Surgical patients was found 27(29.3%) in low RSBI group and 11(44.0%) in high RSBI group (p>0.05).
Conclusion: In conclusion there is no statistical significant relationship of age, gender and clinical diseases
of the patients with low and high rapid shallow breathing index who are under mechanical ventilation at
intensive care unit. [Journal of National Institute of Neurosciences Bangladesh, July 2021;7(2):92-96]
Keywords: Clinico-demographic characteristics; rapid shallow breathing index; mechanical ventilation;
intensive care unit
Correspondence: Dr. Md. Sirajul Islam, Assistant Professor, Department of Critical Care Medicine, National Institute of
Neurosciences and Hospital, Sher-E Bangla Nagar, Agargaon, Dhaka-1207, Bangladesh; Email: sirajulrpmc@gmail.com; Cell no.:
+8801712818254
Conflict of interest: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or
publication of this article.
Funding agency: The authors received no financial support for the research, authorship, and/or publication of this article.
How to cite this article: Islam MS, Mallick UK, Rahman AKMF, Uddin MG, Raka KE. Comparison of Clinico-Demographic
Characteristics and Rapid Shallow Breathing Index of Patients on Mechanical Ventilation at Intensive Care Unit. J Natl Inst
Neurosci Bangladesh, 2021;7(2): 92-96
Copyright: ©2021. Islam et al. Published by Journal of National Institute of Neurosciences Bangladesh. This article is published
under the Creative Commons CC BY-NC License (https://creativecommons.org/licenses/by-nc/4.0/). This license permits use,
distribution and reproduction in any medium, provided the original work is properly cited, and is not used for commercial purposes.
Introduction
Mechanical ventilation in critically ill patients is the
most important support in intensive care unit (ICU)1.
After mechanical ventilatory support, weaning from
92
Comparison of Clinico-Demographic Characteristics and Rapid Shallow Breathing Index of Patients
ventilator is the main challenge in ICU. Weaning of
patients from MV involves two different processes like
ventilator discontinuation and removal of the
endotracheal tube (extubation)2. The decision regarding
the removal of the endotracheal tube is crucial because
both failed extubation and delay extubation associated
with a lot of complications and adverse effects3.
Prolonged mechanical ventilation support in ICU needs
prolonged stay, increases the financial burden and is an
important cause of mortality and morbidity4. On the other
hand, premature extubation may lead to re-intubation,
which also ultimately results in increased length of stay
in ICU, mortality, morbidity and costs5. Therefore,
accurate knowledge of the risk factors and predictors of
extubation failure is needed.
In a developing country like Bangladesh, most of the
critically ill patients are not able to bear the expenses of
ICU6. Other hand there is no cost to measure the RSBI; it
can measure just with the help of mechanical ventilator.
Therefore, this present study was undertaken to compare
the clinico-demographic characteristics and rapid
shallow breathing index of patients on mechanical
ventilation at intensive care unit.
Methodology
This study was conducted in the Department of
Anesthesia, Pain Palliative & Intensive Care Unit of
Dhaka Medical College Hospital, Dhaka, Bangladesh.
This study was a prospective cohort study. This study
was conducted from January 2014 to December 2015.
Non-purposive sampling was applied for this study.
Patients on mechanical ventilation more than 48 hours
with the age of 18 to 60 years after fulfilling the
inclusion and exclusion criteria were included as study
population. Patients with tracheotomy, patients with
spinal cord injury, self extubation or unplanned
extubation, patients who expired before spontaneous
breathing trial, patients shifted to another hospital
before weaning and within 48 hours of weaning were
excluded from this study. Ethical clearance was taken
from Ethical Review Committee of Dhaka Medical
College before starting this study. One type of ventilator
(eVent Medical) was used in all patients. Primary and
daily setting of ventilators and the decision to weaning
of the patient was made by the ICU consultants. During
the weaning process, the arterial blood gases (ABG)
values was checked and the patients was separated from
mechanical ventilation by gradually decreasing the
respiratory rate and pressure support (PS) in SIMV
(synchronized intermittent mandatory ventilation) and
PSV (pressure support ventilation) modes. The rapid
Islam et al
shallow breathing index (RSBI) was defined as the ratio
of respiratory frequency (f) to average exhaled tidal
volume (EVT). When rapid shallow breathing index was
105 breath/min/L or less and more than 105
breath/min/L were taken as low and high RSBI
respectively. The RSBI was measured with the
headboard raised to 30º to 45º and with the patient in
the dorsal decubitus position while monitoring the
patients' vital signs. Tracheal suction was performed as
per need. After measuring RSBI, patients was separated
from mechanical ventilator and given T-piece trial (1 to
4 hours) and finally extubated as per advice of ICU
consultant and observed for 48 hours. Statistical
analyses were carried out by using the Statistical
Package for Social Sciences version 20.0 for Windows
(SPSS Inc., Chicago, Illinois, USA). The mean values
were calculated for continuous variables. The
qualitative observations were expressed by frequencies
and percentages. Chi-Square test was used to analyze
the categorical variables. Student Unpaired t-test was
used for continuous variables such as age, RSBI etc. P
value <0.05 was considered as statistically significant.
Results
A total number of 117 patients were recruited for this
study after fulfilling the inclusion and exclusion criteria
of which 92 patients were in low RSBI group and the
rest 25 patients were in high RSBI group. In this study
it was observed that 36(39.1%) in low RSBI group and
7(28.0%) in high RSBI group patients belonged to age
21-30 years. The mean age was found 31.8±12.8 years
in low RSBI group and 35.9±13.2 years in high RSBI
group. The mean difference was not statistically
significant (p>0.05) between two groups (Table 1).
Table 1: Comparison of Age and Rapid Shallow Breathing
Index (n=117)
Age Group
Low RSBI High RSBI
P value
18 to 20 Years
11(12.0%)
4(16.0%)
21 to 30 Years
36(39.1%)
7(28.0%)
31 to 40 Years
18(19.6%)
6(24.0%)
41 to 50 Years
16(17.4%)
8(32.0%)
51 to 60 Years
8(8.7%)
5(20.0%)
Total
92
25
Mean±SD
31.8±12.8
35.9±13.2
0.161
Range (min, max) 18 to 60
18 to 60
Student t test was performed to see the level of significance.
It was observed that male was found 57(62.0%) in low
RSBI group and 13(52.0%) in high RSBI group. Female
was 35(38.0%) in low RSBI group and 12(48.0%) in
93
Journal of National Institute of Neurosciences Bangladesh
Vol.7 No.2, July 2021
high RSBI group. The difference was not statistically
significant (p>0.05) between two groups (Table 2).
Discussion
Prolonged mechanical ventilation support in ICU needs
prolonged stay, increases the financial burden and is an
important cause of mortality and morbidity7. On the
other hand, premature extubation may lead to
re-intubation, which also ultimately results in increased
length of stay in ICU, mortality, morbidity and costs8.
Therefore, accurate knowledge of the risk factors and
predictors of extubation failure is needed.
A total of 117 patients of ICU who fulfilled the criteria
of extubation after 48 hours in mechanical ventilation
under Anesthesia, Pain, Palliative and Intensive Care
unit of Dhaka Medical College Hospital, Dhaka were
included in this study. Patients with spinal cord injury,
self extubation, unplanned extubation, or MV lasting
<48 hours and patients or attendants not agreeing to
participate in the study were excluded from the study.
The present study findings were discussed and compared
with previously published relevant studies.
In this present study it was observed that more than half
(53.0%) patients had MV in duration of ≤7 days. The
mean duration of MV was found 10.0±6.7 days with
range from 3 to 21 days. Similarly, Bien et al14 observed
the mean duration of MV was 11.0±10.0 days, which is
consistent with the current study. On the other hand,
Fadaii et al8 found that the mean duration of mechanical
ventilation was 17 days varied from 2 to 45 days, which
is higher with the current study.
The rapid shallow breathing index (RSBI) is one of the
most widely investigated predictors of extubation
failure. Values ≤105 cycles/min/L are considered
predictive of extubation success reported by Boles et al9,
Mokhlesi et al10 and Vidotto et al11. In this current study
it was observed that low RSBI (≤105 breath/min/L) was
found 92(78.6%) patients and high RSBI (>105
breath/min/L) was 25(21.4%) patients. The mean RSBI
was found 86.74±16.16 breath/min/L with range from
60.97 to 119 breath/min/L.
In this present study it was observed that 36(39.1%) in
low RSBI group and 7(28.0%) in high RSBI group
patients belonged to age 21-30 years. The mean age was
found 31.8±12.8 years in low RSBI group and
35.9±13.2 years in high RSBI group. The mean age
difference was almost alike between two groups, which
indicates that the difference was not statistically
significant (p>0.05) between two groups. In another
study Mahoori et al12 obtained that the mean age was
69.0±2.0 years in RSBI >105 breath/min/L and 67.0±3.0
years in RSBI <105 breath/min/L). The difference was
not statistically significant (p>0.05) between two
groups. Berg et al13 (2012) found median age was 71
Table 2: Distribution of the Patients by Sex and Rapid
Shallow Breathing Index (n=117)
Gender Low RSBI High RSBI
Total
P value
Male
57(62.0%)
13(52.0%) 70(59.8%)
Female 35(38.0%)
12(48.0%) 47(40.2%) 0.367
Total
92(100.0%) 25(100.0%) 117(100.0%)
Chi-square test was performed to see the level of significance.
The association between diagnosis and rapid shallow
breathing index of the patients were recorded. It was
observed that 14(15.2%) patients had laparotomy in
low RSBI group and 4(16.0%) in high RSBI group.
Others result are depicted in the table. The difference
was not statistically significant (p>0.05) between two
groups (Table 3).
Table 3: Distribution of the patients by diagnosis and rapid
shallow breathing index (n=117)
Diagnosis
Low RSBI High RSBI
Total
P value
Laparotomy
14(15.2%) 4(16.0%) 18(15.4%)
Head injury
12(13.0%) 3(12.0%) 15(12.8%)
operated
GBS
13(14.1%)
0(0.0%)
13(11.1%)
Head injury
8(8.7%)
4(16.0%) 12(10.2%)
non operated
Eclampsia with
8(8.7%)
3(12.0%)
11(9.4%)
0.679ns
HELLP
Sepsis
7(7.6%)
3(12.0%) 10(8.0%)
Encephalopathy 8(8.7%)
2(8.0%)
10(8.0%)
COPD
5(5.4%)
2(8.0%)
7(6.0%)
Other
17(18.5%) 4(16.0%) 21(17.9%)
Total
92(100.0%) 25(100.0%) 117(100.0%)
Chi-square test was performed to see the level of significance.
The association between surgical and non-surgical
patients and rapid shallow breathing index was
recorded. It was observed that surgical patients was
found 27(29.3%) in low RSBI group and 11(44.0%) in
high RSBI group. Non-surgical patients was found
65(70.7%) and 14(56.0%) in low RSBI and high RSBI
groups respectively. The difference was not statistically
significant (p>0.05) between two groups (Table 4).
Table 4: Comparison of Surgical and Non-Surgical Patients
and Rapid Shallow Breathing Index (n=117)
Diagnosis
Surgical
Non-surgical
Total
Low RSBI
27(29.3%)
65(70.7%)
92(100.0%)
High RSBI
Total
P value
11(44.0%) 38(32.5%)
14(56.0%) 79(65.5%) 0.165
25(100.0%) 117(100.0%)
Chi-square test was performed to see the level of significance.
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Comparison of Clinico-Demographic Characteristics and Rapid Shallow Breathing Index of Patients
years in RSBI <105 group and 75 years in RSBI >105
group.
In this current study it was observed that male was
found 57(62.0%) in low RSBI group and 13(52.0%) in
high RSBI group. Female was 35(38.0%) in low RSBI
group and 12(48.0%) in high RSBI group. The
difference was not statistically significant (p>0.05)
between two groups. Similarly, Berg et al13 found female
45 in RSBI <105 group and 10 in RSBI > 105 group.
Fadaii et al8 found male 58.6% and female 41.4%, which
is consistent with the current study. Similarly, Bien et
al14 and Chao and Scheinhorn15 observed male 69.4%
and 51.5% respectively, which are similar to the present
study. On the other hand, Patel et al16 found female
predominance, where they found female 57.0% in their
study patients.
In this series it was observed that 14(15.2%) patients
had laparotomy in low RSBI group and 4(16.0%) in
high RSBI group. GBS was found 13(14.1%) in low
RSBI group. Head injury operated was found 12(13.0)
in low RSBI group and 3(12.0%) in high RSBI group.
Head injury non operated was found 8(8.7%) in low
RSBI group and 4(16.0%) in high RSBI group. The
difference was not statistically significant (p>0.05)
between two groups. Similarly, Berg et al13 found sepsis
9(11.0%) in RSBI <105 group and 6(33.0%) in RSBI
>105 group. Regarding the diagnosis, it was observed in
this series that laparotomy was more common (15.4%)
followed by, 12.8% head injury operated, 11.1% GBS,
10.3% head injury non operated, 9.4% eclampsia with
HELLP syndrome, 8.5% sepsis and 8.5%
encephalopathy, 6.0% COPD and 17.9% had other
diagnosis. Fadaii et al8 observed that sepsis in 7.1%,
COPD exacerbation 22.9% and pneumonia 27.1%. In
another study Bien et al14 obtained that acute
exacerbation of COPD was found 44.0%, pneumonia
was 21.0%, heart failure 10.0%, neurological diseases
10.0%, sepsis 3.0%, others 12.0%. Similarly, Patel et al16
reported that obstructive lung disease was found 6.0%,
pneumonia 6.0%, Congestive heart failure was 15.0%,
and neuromuscular disease was 13.0%. All the above
mentioned study’s findings comparable with the current
study.
In this present study it was observed that surgical
patients were found 27(29.3%) in low RSBI group and
11(44.0%) in high RSBI group. Non-surgical patients
were found 65(70.7%) and 14(56.0%) in low RSBI and
high RSBI groups respectively. The difference was not
statistically significant (p>0.05) between two groups.
Similarly, Kuo et al17 showed the medical and surgical
patients did not significantly differ in any of the
Islam et al
parameters and weaning outcome measured in this
study, which is closely resembled with the present study.
Conclusion
In conclusion there is no statistical significant
relationship of age of the patients under mechanical
ventilation at intensive care unit with low and high
rapid shallow breathing index. Male is predominant
than female considering low and high rapid shallow
breathing index. Laparotomy is more found in low
rapid shallow breathing index patients. Further large
scale study should be carried out to see the level of
significance.
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