http://doi.org/10.33698/NRF0076- Priya Nair, Sukhpal Kaur, Yash Pal Sharma
Abstract : The local side effects associated with subcutaneous heparin, namely pain at the injection site and bruising may be the direct result of faulty injection administration techniques. Various administration variables have been studied, such as needle gauze, injectate volume and syringe size, in an effort to minimize these side effects. One of the variables is the time taken for administering subcutaneous heparin at the injection site. Literature reports that subcutaneous heparin be administered over 10 seconds. In the present study a two group design was used among cardiac patients undergoing heparin therapy. In the control group, the time taken for administering subcutaneous heparin in the routine practice was noted, while in the experimental group 30 seconds injection technique’ was utilized. All other steps of injection administration were kept same in both the groups. A total of 100 injection sites were taken in each group and assessed for pain at 0, 24, 48,60hrs and for bruise at 24, 48 and 60 hrs. It was observed that, in the control group nurses gave the injections over 4-10 seconds. Results show that there was no significant difference in the perceived site pain in both groups. However, when mean bruise sizes were compared, it was observed that they were significantly less in the subjects receiving subcutaneous heparin injection through the 30 second injection duration technique (p<0.05).
Key Words :
Pain, bruise, injection site, low molecular weight heparin, unfractionated heparin, 30 seconds injection technique.
Correspondence at :
Capt Priya Nair
Clinical Instructor
College of Nursing, AFMC, Pune
Introduction
Heparin is one of the most commonly used anticoagulants today. However when heparin, is administered via the subcutaneous route, it has been shown to cause pain and bruising at the injection site.1,2This pain is often the result of injury to the nerve fiber endings located in the skin and tissue from mechanical trauma caused by needle puncture. Another commonly encountered response to subcutaneous heparin injections is the formation of bruise at the injection site. A bruise is a discoloration of the skin caused by extravasation of blood into the subcutaneous tissue as a result of trauma to the underlying blood vessels or the fragility of the vessel wall 3,4 Hadley, Chang and Rogers reported that up to 90% individuals develop a bruise from subcutaneous administration of heparin.3 Vanbree et al revealed that bruising occurred in 53% of subjects out of a total of 43 subjects who received subcutaneous heparin.4 Moreover it is an established fact that subcutaneous heparin should be administered outside a 50 mm radius of a scar, bruise or the umbilicus.5 Based on this fact bruising undoubtedly creates a problem as it limits the possible sites of injections.
The injection administration process effects the formation of bruise and occurrence of pain following subcutaneous heparin injection. Nurses have done research to manipulate various variables of injection administration, in the search of the best technique of administering subcutaneous heparin. These variables include injection site, needle gauge, syringe size, injectate volume injection technique, and injection duration. The present study explores the duration of Injection while administering heparin.
Nursing texts suggests that subcutaneous heparin be administered slowly.6,7 The rationale for this is that slow subcutaneous injection reduces tissue pressure trauma and allows time for the tissue to expand to accommodate the injectate volume. It is possible that when injection is given with speed into the subcutaneous tissue, stretch injury occurs, which results in bruising.
Chan H evaluated the effects of injection duration on site pain and bruising using a 10 second, versus 30 second technique. Each participant received the injections using both 10 second, versus 30 second technique. Immediately following each injection, site pain intensity was measured using a visual analogue scale. Bruising was measured at 48 and 60 hrs after injection. The 10 second injection duration yielded higher pain scores than the 30 second technique. Additionally the 10 second group revealed significantly larger bruises at 48 hrs and 60 hrs than the 30 second injection technique.8 Chenicek TE also conducted a study using the 10 second and 30 second injection duration technique for administering subcutaneous heparin using 34 subjects. The subjects acted as their own control and pain and bruising were assessed after each injection technique. There was no significant difference between the technique used and patient’s perceived level of pain (p=0.941) or measured bruising (p= 0.549).9
Studies show conflicting findings as to which injection duration technique is ideal. Moreover no studies have been done in our country on this particular aspect of injection duration. The researcher has noted that nurses take an average of less than 10 seconds in delivering the injection dose which increased the chances of bruising and also site pain intensity. Thus the present study was conducted to evaluate the effect of time taken in injecting subcutaneous heparin with reference to site pain and bruising.
Materials and Methods
The study was conducted in coronary care unit and cardiothoracic unit, Nehru hospital, PGIMER, Chandigarh in the months of January- February 2007. Patients getting subcutaneous heparin were taken up for the study using purposive sampling. In the control group (routine practice) injections were given by the nurses using a standard protocol which was developed by the researcher; however the time taken by the nurses to administer the injection was not controlled, which was noted by the researcher with the help of a watch. After a total of 100 completed samples were obtained in the control, observation in the control group was started using the 30 second injection duration protocol. Here the nurses gave the injections using the same steps as in control group; however the time taken for injecting the heparin was increased to 30 seconds. A total of 100 samples were taken in the experimental group also.
Concepts of the study were based on Evelyn Adams’ Conceptual model of nursing.10 Data was collected using interview schedule and assessment proformas. Pain was assessed using a Visual Analogue Scale(VAS), which consisted of a 100 mm line in which 0 score indicated no pain, 1-40 mm mild pain, 41-80mm moderate pain and 81-100 mm severe pain. This scale was used by the study subjects to evaluate the intensity of pain at the injection site at 0, 24, 48 and 60 hrs.
The outline of bruise at the injection site was traced on to a transparency using OHP marker. Using a ruler with millimeter demarcations the maximum width and breath was calculated and noted. The area of each bruise was calculated by multiplying the maximum length and the breadth. The bruise measurements were calculated every 24, 48 and 60 hrs. The data was analyzed as per objectives by applying descriptive and inferential statistics.
Results
Mean age of the subjects was 51.76±11.61 years with a range of 20-80 yrs in the experimental group and 56.04±12.54 years with range of 20-79 yrs in the control group. Males were predominant in both groups i.e. 78% in the experimental group and 65% in the control group. Majority of the subjects i.e. 74% in experimental groups and 69% in the control group had coronary artery disease. In the experimental group 6% had unstable angina and 18% had the same diagnosis in the control group. Other diagnosis included rheumatic heart disease, complete heart block, atrial septal defect and myocardial infarction.
In the experimental group 17% of the subjects received only Clopivas whereas only 1% received only Clopivas in the control group. Only ecosprin was received by 10% and 11% subjects in experimental and control group respectively. In the experimental group 69% subjects received both the drugs and in control group 81% subjects received both the drugs
Majority of the subjects received LMWH in both the groups i.e. 78% in the experimental group and 70% in the control group. The rest received unfractionated heparin. Both groups were comparable in terms of age, gender, diagnosis, oral anticoagulants, and type of heparin received (Table 1).
Table- 1: General Characteristics of study subjects
| Sr. no | Characteristics | ‘Routine Practice’ n=100 | 30 sec injection duration ‘technique’ n=100 | c 2 |
| 1 | Age (in years) Mean±SD | 51.76±11.61 | 56.04±12.54 | – |
| 2 | Gender
· Males · Females |
78 22 |
65 35 |
4.18
df=1 NS |
| 3 | Diagnosis
· Coronary artery disease · Complete heart block · Unstable angina · Others |
69 10 18 09 |
74 12 06 08 |
3.24 df=3 NS |
| 4 | Anticoagulants
· Clopivas · Ecosprin · Clopivas+ Ecosprin · Nil |
01 11 81 07 |
17 10 69 04 |
4.8 df=3 NS |
| 5 | Heparin
· Low molecular · weight heparin · Unfractionated heparin |
70
30 |
78
22 |
4.08 df=1 NS |
NS= not significant
Each time the nurses gave the injections, the time taken was noted. The mean time taken by nurses for giving heparin subcutaneously was 6.57± 1.44 seconds
.The time taken by nurses to inject the heparin ranged from 4 seconds to 10 seconds (Table2)
Table – 2 : Time taken by nurses for injecting heparin in routine practice
| Sr. No | Time taken (in seconds) | Frequency of injection n=100 |
| 1 | 04 | 02 |
| 2 | 05 | 16 |
| 3 | 06 | 32 |
| 4 | 07 | 27 |
| 5 | 08 | 12 |
| 6 | 09 | 08 |
| 7 | 10 | 03 |
| Mean time 6.57+1.44 |
Table 3 shows the comparison of mean pain scores among the groups at various time intervals. At 0 hrs after giving the injection, the mean pain score was 30.4+17.56 in the experimental group and 31.19+22.87 in the control group. The difference was not statis- tically significant. After 0 hrs a decreasing trend was noticed in both groups in terms of pain scores. At 60 hrs the mean pain score was 1.43+1.95 in experimental group and 1.49+1.91 in the control group. ‘t’ test was applied to compare the means which showed that the difference in the pain scores were not statistically significant at any of the time intervals they were measured.(i.e. at 24, 48 and 60 hrs)
Table – 3 : Comparison of mean pain scores at injection site between both groups
| Time interval after heparin injection | Experimental group mean±SD | Control group mean±SD | ‘t’- test |
| 0 hr | 30.4± 17.56 | 31.19±22.87 | 0.27,
df=198 NS* |
| 24 hrs | 10.54± 8.42 | 11.53± 6.25 | 0.94 |
| df=198 | |||
| NS* | |||
| 48 hrs | 4.34± 3.87 | 5.11± 3.56 | 1.45 |
| df=198 | |||
| NS* | |||
| 60 hrs | 1.43±1.95 | 1.49± 1.91 | 0.05 |
| df=198 | |||
| NS* |
*Non significant
Bruise area was measured at 24, 48 and 60 hrs after injection. Table 4 shows comparison of mean bruise size between both groups. At 24 hrs the mean bruise size was 0.86mm2+0.83 in the experimental group and 1.47mm2+1.58 in the control group and the difference of mean bruise sizes between both the groups was statistically significant. At 48 hrs the mean bruise size was 2.68mm2±2.09 in experimental group and 3.71mm2± 7.65mm2 in the control group. This difference was not statistically significant. However at 60 hrs the mean bruise size was 3.98mm2± 5.11 in the experimental group and 8.5mm2±22.79 in the control group and the difference was statistically significant.
Table – 4 : Comparison of mean bruise size at injection site between both groups
| Time interval | Experimental group mean±SD | Control group mean±SD | ‘t’ test |
| 24 hrs | 0.86± 0.83 | 1.47± 1.58 | 3.39 |
| df=198 | |||
| p< 0.05 | |||
| S* | |||
| 48 hrs | 2.68± 2.09 | 3.71± 7.65 | 1.28 |
| df=198 | |||
| NS** | |||
| 60 hrs | 3.98± 5.11 | 8.5± 22.79 | 2.0 |
| df=198 | |||
| p<0.05 | |||
| S* |
S* significant
NS** not significant
Discussion
Since the advent of subcutaneous heparin injection for the treatment of cardiac and other ailments, many studies have investigated the least traumatic method of administering injection in order to minimize bruise and patient discomfort due to injection site pain.The current study examined the effect of time taken in administering subcutaneous heparin injection on site pain and bruising (i.e. the time taken in routine practice versus 30 second). The findings revealed that the subjects were homogenous in both groups in terms of age, gender, diagnosis, co- morbidities, anticoagulants received and type of heparin given. Nursing literature suggests that heparin should be given slowly while being given subcutaneously.6,7 10 seconds is the standard time that literature suggests should be taken to administer heparin. In the current study, the mean time taken by the nurse for giving heparin subcutaneously is 6.57±1.44 seconds. In the experimental group the nurses were told to give injections using the same standard technique as they had used in routine practice and only to increase the injection duration to 30 seconds. In the other two studies investigating injection duration, the researchers used a standard 10 sec vs. 30 second technique to give injections. Chan used a within the group study design in which 34 subjects were given the injection twice using different injection durations i.e. 10 seconds and 30 seconds and then subsequently the sites were assessed for pain and bruise8. A similar study design was followed for the study by Chenicek TE9
In the current study analysis of data reveals that mean pain scores in the experimental group were lesser than the control group at 0, 24, 48, and 60 hrs, however, the difference was not statistically significant. The pain experienced by the client is largely at the time of the prick of the needle which causes trauma to tissue and nerve endings. As the needle gauge was kept same in the study i.e. 26 gauge, the pain felt could have been equal in both the group.
In the study done by Chenicek9, the numerical rating scale was used to assess pain and it was found that there was no significant difference in the two groups. The pain scores were noted only at 0 hrs. On the other hand, Chan’s study used the visual analogue scale to rate the pain and it was found that there was significant difference in the pain experienced by the subjects in favor of the 30 sec duration.8 However, unlike the current study, pain was noted only at 0 hrs i.e. immediately after the injection. One explanation of this reduction, given by Chan was that administering the injection slowly over 30 seconds allows the time for the subcutaneous tissue to expand thereby reducing tissue pressure and intensity of site pain experienced.
Mean bruise areas were compared at 24, 48 and 60 hrs in both the groups. At 24 hrs and 60 hrs the difference in bruise sizes between both the groups were statistically significant when’t’ test was applied. The explanation for the difference in the incidence of bruising can be given as follows: slow subcutaneous injection reduces tissue pressure trauma and allows time for the tissue to expand to accommodate the injectate volume.11 It is possible that when injection is given with speed into the subcutaneous tissue, stretch injury occurs, which results in bruising. When we give the injection over 30 seconds the injectate, enters the tissue slowly, thereby preventing rapid distension of the soft tissue.11 In Chan’s study the bruise measurements were taken only at 48 and 60 hrs after injection. At 60 hrs the mean bruise size was 26.03mm 2 ±44.35 in the first group and 1.36mm2 ±1.87 in the second group with mean difference of 24.67 mm2. The range of bruise area in the 10 second injection duration group was from 0-188 mm2 whereas in the 30 second injection duration group the bruise area ranged from 0-6.6 mm2. The findings were highly significant in favor of 30 second injection duration. In Chenicek’s study, the 10 second (mean 0.41± 0.73 mm2) and 30 second (mean 0.56±1.16mm2) bruise measurements differed by 0.15mm2 which was not statistically significant. However the measurements were taken only at 48 hrs after the injection whereas it has been proved that the bruise size peaks at 60 hrs post injection.
Based on the findings it is recommended that subcutaneous heparin injections should be given slowly over 30 seconds by the practicing nurses and nursing teachers should incorporate this practice into their teaching curriculum when they demonstrate subcutaneous injections to the students. Moreover a similar study using a within the group design can be taken up to provide further impetus to these findings.
References
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