Effect of needle gauge on perception of pain intensity among infants receiving D.P.T.Vacacination

http://doi.org/10.33698/NRF0070    Pragya Pathak, Raman Kalia, Bhavneet Bharti

Abstract : Vaccination is the commonest health related procedure carried for children. Though beneficial, injectable vaccinations are a common source of pain. Despite an increased focus on pain assessment in infants, injection related pain remains largely neglected. Since infants cannot communicate their pain, so assessment of pain in infants become all the more important. The W.H.O recommends 23 G. needle for DPT vaccination in infants but practices varies within different institutions. Literature reports that needles of narrow bore inject vaccines with jet pressure, causing more local reactions but its effect on pain has not been studied so far.The present study is undertaken to assess the effect of needle gauge (23G. and 25G.) on vaccination pain among infants. 320 infants receiving DPT vaccine were vaccinated with 25G (n=161) or 23G (n=159) needle in the two randomized groups. Pre and post-vaccination behavior of infants was scored on Modified behavior pain scale (MBPS) and recorded on Video clips. Net change in behavior of infants, indicating intensity of pain perceived was compared. Significant difference in behavioral response to pain was observed among infants in the two groups, t = 4.25, df=318, (p<0.01). The results revealed that 23 G. needle causes less pain as compared to 25 G. needle.

Key Words :Needle Gauge, Pain, Vaccination among infants

Correspondence at :Raman Kalia Lecturer,   National Institute of Nursing Education, PGIMER, Chandigarh, India.

Introduction:Vaccination is the most effective health intervention to reduce morbidity and mortality among children caused due to “Vaccine preventable diseases”. It is also the most common health related procedure, which the infants and young children routinely undergo.1, 2Though beneficial for the health of children, injectable vaccinations, always create some amount of fear to the parents and to the child.3 The correct size of needle and injection technique are very essential to administer the vaccine safely. The size of the needle denotes the length and the diameter of the bore of the needle, termed as the needle gauge. For intramuscular vaccinations if needle is not long enough to reach muscle, more local reactions result. Some of the researches have also been done, to assess the correct sizes of the needles, which can minimize the local reactions.4 The painful experience during vaccination can result in physiological changes within the nervous system. When the procedure is repeated for a number of times, it may decrease the pain threshold and cause hypersensitivity to pain, leading to immediate and long lasting effects on the psyche of the child.5 Pain is the physiological mechanism that protects the individual from a harmful stimulus and serves as a warning to tissue damage. Keeping the importance of pain assessment in mind, many health care institutions have even adopted pain as a “fifth vital sign”. The policy statement by American academy of Pediatrics also states that every heath care facility for neonates should implement an effective pain prevention program by routinely assessing pain. 6, 7 The anatomical, physiological and biochemical pre requisites for pain perception are present by early part of intrauterine life and so even pre term infants can perceive pain in the same way as older children. 8For many years it was believed that babies do not feel pain but this has been disapproved by the researches done on newborns. Anand and Hickey explained that though incomplete myelination may be present in infants but intraneuronal distance is much shorter because of infant’s size, which leads to fast pain  transmission. The density of nociceptor nerve endings in the skin of newborn is also similar to or greater than that in adult skin.9 Though infants experience pain in the same way as adults, but are not able to vocalize it in words, so objective assessment of quality or intensity of pain is very essential in infants. If the pain in infants is not assessed regularly it can lead to serious consequences. The effect of pain in infants are seen in terms of irritability, decreased intake, behavioral problems, altered pain perception etc. 8 To reduce pain among children, Nurses have a great role in exploring ways, to assess and relieve it. Though pain is a subjective experience and present a challenge among parents and health professionals to objectively assess it but through observation of alteration in behavioral and physiological parameters, it can be assessed. 5, 10 Studies have been carried out on a number of variables as use of distraction technique, injection site, needle length etc. but needle gauge is one of variable which is least studied. 11 Though W.H.O recommends 23 G. needle for DPT vaccination in infants,12,13 but there is a diversity in practices of needle gauge used for D.P.T vaccination of infants, within different institutions. So the study was under taken to produce research based evidence.

Objective: To study the effect of needle gauge on pain perception of pain intensity among infants receiving D.P.T vaccination.

Null Hypothesis:There is no significant difference in the perception of pain intensity among infants receiving vaccination with 23G. Vs 25G. needle.

Materials and Methods:The study was conducted at the vaccination room of Advanced Pediatric Centre, PGIMER, Chandigarh in the months of January and February 2007. It is a tertiary level hospital and a referral center with bed strength of1400 beds. Advanced Pediatric Centre (A.P.C) is attached to PGI as exclusive Child care Centre. Vaccination room of A.P.C. is situated at ground floor in the D Block and it has all the facilities for storage of vaccines and their safe administration. Written permission was obtained from O.P.D. consultant incharge of A.P.C. for conducting the study. Infants upto 24wks age receiving D.P.T. vaccination (n=320) were included in the study. Randomization of study samples was done for assigning the 23G and 25G needles. Experimental group I comprised of 161 infants vaccinated with 25G needle while Experimental group II had 159 infants vaccinated with 23G needle. The groups were blinded to the researcher. Performa for sample selection and pain assessment were prepared. Content validity of the tools was established by experts in the field of Pediatrics, Nursing education and child psychology. Feasibility of the study was tested. After selecting the study samples on the basis of inclusion criteria, baseline assessment of infants behavior was done on Modified Behavior Pain Scale. Video clips of infant’s were taken during vaccination. Post vaccination mother and researcher scored pain on Visual analogue scale. Duration of cry was recorded. Video clips were reviewed to score post vaccination behavior of infant, on Modified Behavior Pain Scale. Net pain scores were calculated by subtracting pre vaccination scores from post vaccination scores. The behavioral response to pain shown by infant indicated the intensity of pain perceived.

Results:Table 1 depicts, the demographic variables of subjects in the two groups. Subjects in both the experimental groups were comparable as per the age, gender and dose of D.P.T. vaccine received.

Table – 1 : Distribution of subject according to their age, gender. Weight and dose of vaccination received.

Expt. Group I (n = 161)          Expt. Group II (n = 159)         c2

f (%) f (%) Test
AGE (Weeks)
£ 6 73 (45.3) 64 (40.3) 0.98
7-12 44 (27.3) 50 (31.4) df = 2
13 & above 44 (27.4) 45 (28.3) N.S*
Gender
Males 102 (63.4) 88 (55.3) 1.80
 

Females

  

59

  

(36.6)

  

71

  

(44.7)

 df = 1

NS*
Weight
Normal 133 (82.6) 141 (88.7) 1.93
 

Malnourished

  

28

  

(17.4)

  

18

  

(11.3)

 df = 1

NS*
Dose
1st dose 82 (50.9) 78 (49.0) 0.52
2nd dose 43 (26.7) 40 (25.2) df = 2
3rd dose 36 (22.4) 41 (25.8) NS*

Expt.group I- Infants vaccinated with 25G needle                 Expt.group II- Infants vaccinated with 23G needle

*NS = Not Significant Table 2, depicts the distribution and comparison of net pain scores of study subjects in the two experimental groups. In experiment group I, out of 161, half of the study subjects 87 (54.0%) had net pain scores between 7-10 (severe pain), while in experimental group II, out of 159, two third of the study subjects 111(69.8%) had net pain scores between 4-6 (moderate pain). Mean Net pain scores of subjects in two experimental groups were compared, mean net pain score of study subjects in experimental group I, was 6.6 while in experimental group II, it was 5.9. t test was applied to compare the means.(t calculated = 4.25 at df = 318,p< 0.01). Calculated value of t was more than tabulated value of t. There is a significant difference in net pain scores of study subjects in the two experimental groups.

Table 1 :   Comparison of subjects as per pain scores on Modified Behavior Pain Scale (MBPS)                                                                                               N=320

 

Pain scores on MBPS Expt. Group I (n = 161) Expt. Group II (n =159)
Range (Scores) f (%) Range (Scores) f     (%)
Pre-Vaccination scores 0 – 3 157 (97.5) 157 (98.7)
4 – 6 0 – 3 04 (02.5) 0 – 5 02 (01.3)
7 – 10 – –
Post-Vaccination scores
0 – 3 – –
4 – 6 04 -10 42 (26.1) 05 – 10 72 (45.3)
7 – 10 119 (73.9) 87 (54.7)
Net pain scores *
0 – 3 02 (01.2) 04 (02.5)
4 – 6 02 – 09 72 (44.7) 03 – 09 111 (69.8)
7 – 10 87 (54.0) 44 (27.7)
Mean Pain Score S.D 6.6±1.5 5.9 ±1.3
t test 4.25, df = 318, p<0.01

(Net pain scores on MBPS = Post-vaccination MBPS scores – Pre-vaccination MBPS scores.) Maximum M.B.P.S score = 10, 0-3 Mild Pain, 4-6 Moderate Pain, 7-10 – Severe Pain.

Discussion: Inspite of an increased focus on pain assessment and management among infants, injection related pain remains largely untreated and thus is a cause of concern among health professionals. With the introduction of new vaccines, children now receive upto 15 injections by two years of age.2 Vaccine associated pain affects physical and mental well-being of child as well as parents3. Studies have been done on a number of variables associated with vaccination pain among children.4,14,15 But no study has been done so far, to assess the effect of gauge of needle on vaccination pain among infants. Though W.H.O prescribes the standard size of needles and technique for vaccination  of infant,1\2,13  but the practices regarding the size of needle to be used for intramuscular injections varies within different institutions. So this study was taken up with the objective, to assess the effect of needle gauge on perception of pain intensity among infants receiving vaccination.In the present study, infants receiving DPT and its combination vaccines were taken up as study subjects, as DPT vaccines comprises the bulk share of the vaccine administered to the infants. For this very reason a number of other researchers have also preferred to take subjects receiving DPT vaccination.4,14,15 The study subjects in the present study were upto 24 weeks; as this is the age in which DPT vaccine is administered to children. Other researchers have also taken subjects upto 24 weeks of age in their studies on vaccination in infants.15 Assessing pain among infants have been a tremendous challenge among researchers because of the inability of infants to report for pain they perceive. Researchers have used behavioral and physiological parameters to assess pain in infants. In present study (MBPS) was used to objectively assess pain expressed by infants on the basis of behavioral responses to the pain.14,15,16 Video clips were taken to increase the objectivity of observations and increase the reliability of data. Similar tools and parameters have also been used by other researchers to observe vaccination pain of infants. 1415,17,18 Contrary to the belief that smaller needles cause less pain, the study findings revealed that vaccination with smaller bore needle (25G.), caused more pain in infants as compared to those vaccinated with 23G. needle. However no studies are available to support the findings. It is likely to be caused by jet pressure created through narrow bore of needle (25G.) when the vaccine is injected.4 In the present study, male infants were predominant in both the groups. The findings of the study revealed no significant difference in pain scores of male and female infants. Similar findings were also reported in a study by Ipp M. Findings indicate that gender does not influence pain response among infants. 15 As researches report developmental difference in expression of pain by infants, so in the present study, pain scores of infants within different age groups were compared. Study findings revealed no significant difference in pain among infants within different age groups. Similar findings were also reported by Johnston et al. among infants, aged 2 to 4 months.17 While in a study by Lilley et al, developmental differences in expression of pain were observed among infants.18 The results of the present study reveal that vaccination of infants with 23G. needle results in less pain as compared to 25 G. needle. Gender does not influence pain response among infants and there is no significant difference in behavioral response to pain among infants upto 24 weeks age.

Recommendation :The study recommends the use of 23G. needle for D.P.T. vaccination of infants.

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