BACKGROUND AND SIGNIFICANCE OF STUDY:

Many patients admitted into the intensive care unit require airway maintenance and mechanical ventilator support. It is important that all qualified nurses working in critical care environments understand the indications for the use of mechanical ventilation, the modes of ventilation delivery and the most common associated complications.¹

The early history of mechanical ventilation begins with various versions of what was eventually called as the iron lung, a form of noninvasive negative pressure ventilator widely used during the polio epidemics of the 20th century after the introduction of the "Drinker respirator" in 1928 and the subsequent improvements introduced by John Haven Emerson in 1931. Other forms of noninvasive ventilators are also used widely for polio patients that include Biphasic Cuirass Ventilation, the rocking bed and rather primitive positive pressure machines.

During poliomyelitis and tuberculosis pandemics in the middle of the twentieth century, special units were established, equipped with technical equipment to manage the airway and ventilate the patient and staffed by specialized care providers.² The intensive care unit remains a setting where death is common, and a large proportion of these deaths are preceded by withdrawal of life support.³

The various techniques used in mechanical ventilation to help patients breathe are called modes. Generally, modes are controlled or assisted. In controlled ventilation, the ventilator initiates the breath and does all the work of breathing. In assisted ventilation, the patient initiates and terminates some or all the breaths, with the ventilator giving various amounts of support throughout the respiratory cycle. Hence, the modes of ventilation vary in the degree of the patient’s effort versus ventilator support.

Modes of positive pressure ventilation can be divided into 2 groups: volume-targeted and pressure-targeted. In volume-targeted ventilation, the limit variable during inspiration is the preset tidal volume. Volume-targeted modes, such as continuous mandatory ventilation (CMV), assist/control (A/C), and synchronized intermittent mandatory ventilation (SIMV) have been the favored ventilatory support modes in adults for the past 25 years. In pressure-targeted ventilation, pressure, the target, is held constant at a preset level throughout inspiration. Modes that operate in this fashion are pressure-support (PS), pressure-control, pressure A/C, and airway pressure-release ventilation (APRV). In the past decade, use of pressure-targeted modes has become more widespread.⁴ Nurses must be knowledgeable about the function and limitations of ventilator modes, causes of respiratory distress and dyssynchrony with the ventilator and appropriate management in order to provide high-quality patient-centered care.⁵

In patients requiring mechanical ventilation, weaning failure is relatively common, with an estimated prevalence of 31% and a range 26–42%. When initial attempts at spontaneous breathing fail to achieve the goal of liberation from mechanical ventilation, clinicians must choose appropriate modes of ventilator support which: 1) maintain a favourable balance between respiratory system capacity and load; 2) attempt to avoid diaphragm muscle atrophy; and 3) aid in the weaning process.³

Review of literature

A study was conducted on “pressure modification for improving usage of continuous positive airway pressure (CPAP) machines in adults with obstructive sleep apnoea” in Cambridge, England. The researcher used randomised controlled trials assessing interventions to improve compliance with CPAP usage. The control groups received fixed pressure CPAP. The study concluded that there is improvement in average machine use of auto CPAP when compared with the use of fixed pressure CPAP⁶.

A study was conducted on “work of breathing in adaptive pressure control continuous mandatory ventilation” in Cleveland, America. The purpose of the study is to evaluate the relationship between ventilator work output and patient effort in adaptive pressure control. The results indicate that the patient’s work of breathing increased from 0J/L to 1.88J/L through the step increase in muscle pressure. The study concluded that adaptive pressure control algorithms differ between ventilators in their response to increasing patient effort⁷.

A study conducted on “continuous negative extrathorasic pressure (CNEP) or continuous positive airway pressure (CPAP) for acute hypoxemic respiratory failure (AHRF) in children” in Ontario, Canada. The study included randomized or quasi randomized clinical trials of either CNEP or CPAP versus standard therapy( positive pressure ventilation ) involving children at least one month old and less than 18years of age who met criteria for diagnosis of AHRF with fraction of inspired oxygen>40%. The result findings indicated that there is reduction in the fraction of inspired oxygen (FiO2<30%) in the CNEP group compared to none in the control group. The study concluded that there is a lack of well designed, controlled experiments of non-invasive modes of respiratory support in children with acute hypoxemic respiratory failure⁸.

MATERIAL AND METHODS:

Research design

The research design selected for the present study was pre- experimental with one group pre-test and post-test design, in which pre-test was conducted followed by structured teaching programme (STP) and then conducting post-test for the same group after 8 days.

Population

Population in the study consists of staff nurses working at Kempegowda Institute of Medical Sciences, Hospital and Research Centre, Bangalore.

Sample Size and Sampling Technique

The sample size for the present study is 60 nurses working at Kempegowda Institute of Medical Sciences, Hospital and Research Centre, Bangalore. Purposive sampling was considered appropriate for the study.

Tool of research

Based on the objectives of the study, a structured knowledge questionnaire was prepared in order to assess the knowledge of nurses on modes of mechanical ventilator.

Selection and Development of Instrument

A structured questionnaire was prepared to assess the knowledge of nurses regarding modes of mechanical ventilator.

The tool was selected based on the research problem, review of the related literature and with suggestions and guidance of experts in the field of Medical and Surgical Nursing, Anaesthetist, Statistician, English language expert, Psychologist and Sociologist. The tool was prepared on the basis of objectives of the study. The final tool was prepared with guidance and suggestion of the guide.

Procedure of data collection:

(a) Permission from the Concerned Authority

Formal prior permission was obtained from the Nursing Superintendent and Medical superintendent of Kempegowda Institute of Medical Sciences, Hospital and Research Centre, Bangalore to conduct the study through the principal, Kempegowda College of Nursing, Bangalore-02 and the study was conducted as per the schedule.

(b) Pre test (O₁)

The structured knowledge questionnaire was used to collect the data from the nurses at Kempegowda Institute of Medical Sciences, Hospital and Research Centre, Bangalore after obtaining permission from authority and consent from the subjects. The investigator collected data from 60 nurses; it took 50-55 minutes for each nurse to complete the structured knowledge questionnaire.

(d) Implementation of Structured Teaching Programme (X)

Followed by pre test, on same day Structure Teaching Program was conducted by the investigator for a period of 50 minutes by using appropriate visual aids.

(e) Post test (O₂)

The same Structured Knowledge Questionnaire was used to collect the post test data. Post test data was collected on 8^th day after Structured Teaching Programme.

Plan of data analysis:

The data obtained was analysed in terms of achieving the objectives of the study using descriptive and inferential statistics.

Statistical Analysis of Data

1. Entering the data in master sheet.

2. Frequencies and percentages are used for analysis of demographic characteristics.

3. Calculation of mean, and standard deviation of pre-test and post-test scores.

4. Application of paired‘t’ test to ascertain whether there is significant difference in the mean knowledge score of pre-test and post-test values.

5. Application of chi-square to find the association between demographic variables with knowledge scores.

RESULTS:

Analysis and interpretation of data

An evaluative approach was adopted to assess the effectiveness of structured teaching programme on modes of mechanical ventilator among staff nurses.

The data was collected utilizing the structured questionnaire. The data collected from the respondents were organized, tabulated, analyzed and interpreted by applying descriptive and inferential statistics based on the objectives of the study.

Presentation of data

The collected data was entered in a master sheet, for the tabulation and statistical processing. The findings were classified and presented under two sections.

Section I: Distribution of respondents according to demographic variables.

Section II: Distribution of scores in pre-test and post-test.

A: Component wise distribution of scores during pre-test and post-test.

B: Association between pre-test and post-test knowledge scores.

C. Association between knowledge scores with selected demographic variables.

D. Component wise distribution of knowledge scores in pre-test and post-test.

Section-I: Demographic Profile

Distribution of Respondents by Age

The majority 42(70%) of subjects were in the age group of 26-30 and 10(16.7%) of subjects were in between the age of 21-25. Only 8(13.3%) of subjects were in the age group of 31 and above.

Distribution of Respondents by Sex

All the samples included in the study were females thus contributing to 60 (100%).

Distribution of Respondents by Education

The majority of samples 33 (55%) had GNM as their professional qualification and 27 (45%) were having B.Sc.Nursing as their professional qualification.

Distribution of Respondents by Marital Status

Among all the samples participated in the study, the majority of them 40 (66.7%) were married and 20 (33.3%) were unmarried.

Distribution of Respondents by Religion

Among the distribution of respondents by Religion, among which the majority of the samples 42 (70.0%) belongs to Hindu Religion and 18 (28.3%) belongs to Christian Religion.

Distribution of Respondents by Department

The majority of the respondents were from 12(20%) Surgical ICU, 11(18.3%) were from Medical ICU, 10(16.7%) were from both Surgical and Pediatric ward, 9(15%) are working in Pediatric ICU and 8 (13.3%) are working in Medical ward.

Distribution of Respondents by Clinical Experience

The majority of the samples 42(70%) are having clinical experience of 0-5 years, 16(26.7%) of the samples are having 6-10 years of clinical experience and 2 (3.3%) of them are having above 11 years of clinical experience.

Distribution of Respondents by Family

The majority of the samples 42(66.7%) belongs to nuclear family and 18(33.3%) samples belongs to joint family.

Distribution of Respondents by Income

The majority of the samples 33(55%) has income between Rs.10000-Rs.20000, 17(28.3%) has income between Rs.20000-Rs.30000 and 10(16.7%) are in between Rs.30000-Rs.40000.

Section II

A. Component wise distribution of scores during the pre test and post test.

From the table 1, it is noticed that the mean ±SD of age is 27.78± 2.457 which ranges from 24 to 34 years. The median age is 27.5 years and the mean ±SD of clinical experience is 4.43±2.332, which ranges from 1 to 11 years. The median of clinical experience is 4 years. The overall pre-test knowledge scores which ranges from 17 to 22 where the maximum score is 48, the median score is 19 and the mean ±SD is 19.31±1.610. The overall post test knowledge score which ranges from 34 to 40, where the maximum score is 48, the median is 36 and the mean ±SD is 35.87±1.672.

Table 1: Descriptive statistics of age and overall knowledge score of pre-test and post-test scores

	Range	Median	Mean	SD
Age(yrs)	24-34	27.5	27.78	2.457
Experience (yrs)	1-11	4	4.43	2.332
Overall pre-test knowledge scores	17-22	19	19.31	1.610
Overall post-test knowledge scores	34-40	36	35.87	1.672

The results of statistical data analysis in table 4 shows that, in all areas the mean percentage of the knowledge score of the subjects in the post test has increased significantly when compared to the pre test knowledge score. The mean percentage enhancement values of the knowledge scores shows that there has been a minimum increase of 30.78% in the aspect of weaning and nursing care of patients with mechanical ventilator, whereas the maximum enhancement of mean percentage was 38.63% in the aspect of modes of mechanical ventilator.

Table 2: Component / Aspects wise pre-test mean knowledge scores.

Component wise analysis of pretest knowledge score	Max. Score	Range	Median	Mean	SD	Mean (%)
Knowledge regarding physiology of lungs.	10	3-7	5	4.53	1.016	45.3
Knowledge regarding mechanical ventilator.	13	2-8	5	4.95	1.281	38.07
Knowledge regarding modes of mechanical ventilator.	16	3-9	6	5.67	1.361	35.43
Knowledge regarding weaning and nursing care of patients with mechanical ventilator.	9	1-6	4	3.98	1.049	44.22
Overall pre-test knowledge score	48	17-22	19	19.13	1.610	39.85

Overall pre-test knowledge score: This comprises of a maximum score of 48. It ranges from 17 to 22. The subjects had a mean of 19.13 with a standard deviation of 1.610 and the mean percentage of 39.85%.

Table 3: Component / Aspect wise analysis of post-test knowledge scores N = 60

Component wise analysis of pretest knowledge score	Max. score	Range	Median	Mean	SD	Mean (%)
Knowledge regarding physiology of lungs.	10	6-9	8	7.82	0.792	78.2
Knowledge regarding mechanical ventilator.	13	6-12	9	9.45	1.096	72.69
Knowledge regarding modes of mechanical ventilator.	16	10-14	11	11.85	1.338	74.06
Knowledge regarding weaning and nursing care of patients with mechanical ventilator.	9	5-9	7	6.75	0.876	75.0
Overall post-test knowledge score	48	34-40	36	35.87	1.672	74.72

Overall post-test knowledge score: This comprises of a maximum score of 48. The range is from 34 to 40. The subjects had a mean of 35.87 with a standard deviation of 1.672 and the mean percentage of 74.72%.

B. Association between pre–test and post-test knowledge scores

Table 4: Comparison of different aspects of knowledge between pre-test to post-test N = 60

Aspect wise analysis of knowledge score	Pre-test data				Post test data			Mean Percentage of enhancement
Aspect wise analysis of knowledge score	Max. score	Mean	SD	Mean %	Mean	SD	Mean %	Mean Percentage of enhancement
Knowledge regarding physiology of lungs.	10	4.53	1.01	45.3	7.82	0.79	78.2	32.9
Knowledge regarding mechanical ventilator.	13	4.95	1.28	38.07	9.45	1.09	72.69	34.62
Knowledge regarding modes of mechanical ventilator.	16	5.67	1.36	35.43	11.85	1.33	74.06	38.63
Knowledge regarding weaning and nursing care of patients with mechanical ventilator.	9	3.98	1.04	44.22	6.75	0.87	75.0	30.78
Overall post test knowledge score	48	19.13	1.61	39.85	35.87	1.67	74.72	34.67

Table 5: Aspect / component wise statistical analyses of pre-test and post-test mean knowledge score of respondents N = 60 P value<0.05

Aspect / component wise	Pre-test		Post-test		t- value	Inference
Aspect / component wise	Mean	SD	Mean	SD	t- value	Inference
Physiology of lungs.	4.53	1.01	7.82	0.79	20.129	S
Mechanical ventilator.	4.95	1.28	9.45	1.09	19.689	S
Modes of mechanical ventilator.	5.67	1.36	11.85	1.33	24.000	S
Weaning and Nursing care of patients with mechanical ventilator.	3.98	1.04	6.75	0.87	13.976	S
Overall post- test knowledge scores	19.13	1.61	35.87	1.67	59.315	S

^Sis significant

Table 6: Levels of pre-test and post-test scores based on different aspects N = 60

Different aspect wise	Pre test			Post test
Different aspect wise	£ 50%	51-75%	>75%	£50%	51-75%	>75%
Physiology of lungs.	51	9	-	-	19	41
Mechanical ventilator.	55	5	-	-	21	39
Modes of mechanical ventilator.	59	1	-	-	20	40
Weaning and Nursing care of patients with mechanical ventilator.	43	17	-	-	10	50
Overall post- test knowledge scores	60	-	-	-	28	32

Note: 50% - Inadequate Knowledge, 51-75%- Moderate Knowledge, 75%- Adequate Knowledge

Overall knowledge:

The data from the table represents that all 60 nurses had inadequate knowledge in pre-test whereas in post-test 28 of them had moderate knowledge and 32 nurses had adequate knowledge.

Table 7: Analysis of association between selected demographic variables and over all pre-test knowledge scores. N= 60

Demographic variables	Responses	Overall pre-test knowledge		Chi- square value	df
		Below median	Above median
Age (yrs)	Below 28	19	23	0.003^NS	1
	Above 28	8	10
Sex	Female	27	33
Education	GNM	14	19	0.197^NS	1
	B.Sc. Nursing	13	14
Marital status	Unmarried	9	11	0.000^NS	1
	Married	18	22
Religion	Hindu	20	22	0.388^NS	1
	Christian	7	11
Department	Ward	12	16	0.097^NS	1
	Intensive care unit	15	17
Family	Nuclear	17	25	1.158^NS	1
	Joint	10	8
Experience	Below 5	19	23	0.003^NS	1
	Above 5	8	10
Income	Below 20,000	13	20	0.931^NS	1
	20,000 and above	14	13

^Sis significant; ^NSis not significant

Note: Some of the demographic variables have been merged as the expected frequencies was less than or equal to 5.

Critical value for df 1 at 5%level of significance=3.841.

Table 8: Analysis of association between selected demographic variables and over all post-test knowledge scores. N= 60

Demographic variables	Responses	Overall pre-test knowledge		Chi- square value	df
		Below median	Above median
Age (yrs)	Below 28	21	21	0.156^NS	1
	Above 28	8	10
Sex	Female	29	31
Education	GNM	18	15	1.133^NS	1
	B.Sc.Nursing	11	16
Marital status	Unmarried	10	10	0.033^NS	1
	Married	19	21
Religion	Hindu	20	22	0.029^NS	1
	Christian	9	9
Department	Ward	12	16	0.630^NS	1
	Intensive care unit	17	15
Family	Nuclear	17	25	3.461^NS	1
	Joint	12	6
Experience	Below 5	20	19	0.388^NS	1
	Above 5	9	12
Income	Below 20,000	15	18	0.243^NS	1
	20,000 and above	14	13

^Sis significant; ^NSis not significant

Note:

1. Some demographic variables have been merged as the expected frequencies were less than or equal to 5.

2. Critical value for df 1 at 5% level of significance = 3.841.

From the above data, there is no significant association between demographic variables and knowledge scores.

DISCUSSION:

The findings of the study are discussed under the following headings:

1. The knowledge of nurses on modes of mechanical ventilator.

2. The effectiveness of structured teaching programme on modes of mechanical ventilator.

3. Association between the demographic variables and the overall pre-test and post-test knowledge scores.

4. Discussion related to the testing of hypothesis.

1. The knowledge of nurses on mechanical ventilator.

The present study confirms that the overall knowledge levels of nurses was significantly low in the pre-test with the overall mean pre-test knowledge scores of 39.85% when compared to the mean post-test knowledge scores of 74.72%.

A study was conducted by Rose L on “clinical application of ventilator modes: ventilatory strategies for lung protection” in Canada. The aim of the study is to present an overview of current knowledge and research relating to lung protective ventilation. The study results indicate that lung protective strategies using low tidal volumes and moderate levels of positive end expiratory pressure have been recommended as strategies to prevent tidal alveolar collapse and overdistension in patients with acute lung injury/acute respiratory distress syndrome. The study concluded that weaning and extubation continue to be delayed and Critical care nurses need to establish a strong knowledge base to promote effective and appropriate management of patients requiring mechanical ventilation.⁹

A similar study was conducted by Pertab D on “Principles of mechanical ventilation – A Critical review” in UK. The study explores the principles underpinning artificial ventilation, explains the difference between positive and negative pressure ventilation and differentiates between invasive and non-invasive modes of ventilation. The study concludes that ventilator practice requires knowledge to ensure choosing the right ventilator.¹⁰

2. The effectiveness of structured teaching programme on mechanical ventilator.

The present study confirms that there was a considerable improvement of knowledge after the STP and is statistically established as significant.

A similar study was conducted on “effect of an education program aimed at reducing the occurrence of ventilator associated pneumonia” in Barnes-Jewish Hospital. The study used pre and post intervention observational study of five intensive care units. The result findings indicate that the rate of ventilator associated pneumonia decreased to 57.6 %( p<0.001). The study concluded that a focused education intervention can dramatically decrease the incidence of ventilator associated pneumonia. Education programs should be more widely employed for infection control in the intensive care unit setting and can lead to substantial decreases in cost and patient morbidity attributed to hospital acquired infections¹¹.

3. Association between demographic variables and over all pre-test and post-test knowledge scores.

In this study when demographic variables were analyzed, there was no significant association found at 0.05 level between pre-test knowledge scores of nurses and the selected demographic variables.

A study was conducted on “evidence–based guidelines for the prevention of ventilator associated pneumonia: results of a knowledge test among intensive care nurses” in UK. The study included demographic data such as gender, years of intensive care experience, number of critical beds and special degree in intensive care. The study used multiple choice questionnaires for 638 samples and the response rate was 74.6%. The knowledge level was higher among experienced nurses and those holding a special degree in intensive care unit. The study concluded that nurses lack knowledge regarding recommendations for ventilator associated pneumonia prevention and continuing education should include support from current evidence-based guidelines.¹²

4. Discussion related to testing of hypothesis.

H₁ There is a significant improvement in the post-test knowledge score compare to the pre-test knowledge score of staff nurses.

The research hypothesis H₁ stated in the study is accepted since there is significant improvement found between the pre-test and post-test knowledge scores on modes of mechanical ventilator among nurses at P < 0.05 level (5%) after administration of the structured teaching programme.

H₂ There is a significant association between pre test knowledge score with selected demographic variables.

The investigator rejects the research hypothesis because there is no significant association between demographic variables with pre test knowledge scores.

ACKNOWLEDGEMENTS:

I thank God Almighty, the path of light and the ray of hope of my life for his grace and endless blessings throughout my study.

I owe a deep sense of gratitude to all those who have contributed for the successful completion of the study.

I convey my sincere indebtedness to the Kempegowda College of Nursing, Bangalore-04, for providing me an opportunity to be a student of this esteemed institution and to conduct this study.

I extend my sincere thanks to Mrs. V.T. Lakshmamma., M.Sc. N., Principal and HOD, Community Health Nursing, Kempegowda College of Nursing, Bangalore-4, who let me and my search move around freely. I owe a deep sense of gratitude and indebtedness to her.

My heartfelt thanks to my guide Prof. Shivananda, HOD, Medical Surgical Nursing, who deserves respect and gratitude for his inspiration, words of encouragement and his untiring guidance, showing immense interest and support throughout the course of the study.

I extend my sincere thanks to Faculty Members of Department of Medical Surgical Nursing and all the Faculty of Kempegowda College of Nursing, Bangalore-4, for their constant guidance and helpful support during the entire course of the study.

I wish to place my sincere thanks to Mrs. Rajeshwari, Department of English, College of arts and commerce, Bangalore for editing the manuscript meticulously for editing the tool.

I am thankful to Mr. Venkatesh and Mr. Gopal, Librarians and assistant librarian Mrs. Mangala who helped me in availing the library facilities.

I would fail in my duty if I forget the Staff nurses working in Kempegowda Institute of Medical Sciences, Hospital and Research Centre, Bangalore who participated in this study. It is because of them this thesis has seen the light of the world.

My healthy ovation of gratitude to my parents and my brothers for their encouragement and support though out this study.

A Heartfelt thanks to my classmates, juniors and all my friends for their untiring support. Finally, I thank all those well-wishers of mine who have directly or in directly contributed to the success of this work.

REFERENCE:

1. Higginson R. The role f the nurse in mechanical ventilation. British journal of nurses 2011Nov 24; 20(21):1341.

2. Mechanical ventilation [Online]. Cited 2012 Jan 20; Available from:http://en.wikipedia.org/wiki/Mechanical _ventilation

3. Bokes M J, Bion J, Marsh B. Weaning from mechanical ventilation. critical care 2007May 1; 29(5):1033-56.

4. Lynelle N B. Traditional and nontraditional modes of mechanical ventilation. Critical care nurse2002;22:56-59.

5. Grossbach I, Chlan L, Tracy MF. Overview of mechanical ventilatory support and management of patient- and ventilator-related responses. Critical care nurses 2011Jun;31(3):30-44.

6. Smith I, Lasserson TJ. Pressure modification for improving usage of continuous positive airway pressure machines in adults with obstructive sleep apnoea. Cochrane database system review. 2009 Oct7; (4):CD00353.

7. Mireles C, Chatburn. Work of breathing in adaptive pressure control continuous mandatory ventilation. Respiratory care.2009Nov; 54(11):1467-72

8. Shah PS, Ohlossan A, Shah JP. Continuous negative extrathoracic pressure or continuous positive airway pressure for acute hypoxemic respiratory failure in children. Cochrane database system review. 2008 Jan23 ;(1):CD003699.

9. Rose L. Clinical application of ventilator modes;ventilator strategies for lung protection. Australian critical care. 2010 May;23(2):71-80.

10. Pertab D. Principles of mechanical ventilation-a critical review; British journal of nurses. 2009 Aug 13-Sep 9;18(15):915-8.

11. Zack, Jeanne E, Garrison, Teresa, Trovillion, Ellen et el. Effect of an education program aimed at reducing the occurrence of ventilator associated pneumonia. Critical care medicine.2002Nov;30(11):2407-12.

12. Labeau S,Vandick D, Rello J. Adam S, Evidence based guidelines for the prevention of ventilator associated pneumonia; results of a knowledge test among intensive care nurses. Journal of Hospital Infection. 2008 Oct;70(2):180-5.

Received on 19.08.2014 Modified on 08.09.2014

Asian J. Nur. Edu. and Research 5(1): Jan.-March 2015; Page 98-104

DOI: 10.5958/2349-2996.2015.00021.X

Effectiveness of Structured Teaching Programme on Knowledge regarding modes of Mechanical Ventilator among Staff Nurses at a selected Hospital, Bangalore