Effect of injectate volume on local hematoma formation during low-dose heparin therapy

Occurrence and extent of bruising according to duration of administration of subcutaneous low-molecular-weight heparin: a quasi-experimental case-crossover study

BACKGROUND

Several authors have documented the role of low-molecular-weight heparin injection techniques in bruising. However, few researchers have measured the influence of injection duration on the occurrence and extent of bruising.

PURPOSE

The aim of this study was to evaluate the influence of different durations of subcutaneous heparin injection on the occurrence and extent of bruising.

METHODS

A quasi-experimental case-crossover study design was adopted in 2010. A consecutive series of patients admitted to 2 orthopedic units in a large (600 beds) teaching hospital located in northern Italy were eligible for enrolment. Injections were administered following a standard procedure. The manipulated variable was the duration of the injection, 10 seconds (treatment A) and 30 seconds (treatment B). The evaluation of bruise occurrence and extension performed after 48 hours and data analysis were conducted in a blinded fashion.

RESULTS

A total of 150 patients receiving their first and second subcutaneous heparin injections (300 injections) were enrolled. Eighty-seven bruises were observed out of 300 injections (29%): 57 of 150 (38%) after injections lasting 10 seconds and 30 of 150 (20%) after injections lasting 30 seconds (relative risk, 1.50; 95% confidence interval, 1.21-1.86; P = .00). Of the 87 bruises that occurred, 69 (79.3%) were small (2-5 mm) and 18 (20.6%) were large (>5 mm), with no difference in size between 10- and 30-second injections (relative risk, 0.91; 95% confidence interval, 0.39-2.12; P = .83).

CONCLUSIONS

Low-molecular-weight heparin injection should be administered over 30 seconds to decrease bruising.

CLINICAL IMPLICATIONS

There is a need to reflect on the feasibility of such a practice because injecting low-molecular-weight heparin at 30 seconds requires accuracy, a steady hand, the absence of tremor, a calm environment, and the ability to administer an infinitesimally small amount of liquid (eg, 0.4 mL) per second.

Assessment of four different methods in subcutaneous heparin applications with regard to causing bruise and pain

Subcutaneous administration of the anticoagulant heparin sodium is a frequently performed nursing intervention. Subcutaneous heparin injection often causes problems such as bruise, pain, induration, and hematoma at the injection site. Bruising that result from heparin injections may lead to anxiety, disruption of body image, the rejection of the treatment in patients, and the reduction of the reliance of patient to nurse. The purpose of this study was to determine and compare the effects of four different injection technique pain and on bruising associated with subcutaneous heparin. The research involved ninety-five patients. Each subject received four injections by the same investigator using four different techniques. Site bruising was measured at forty-eight and seventy-two after each injection. The bruising size was measured using milimetric transparent palyethylene wrap and the verbal pain scale. There was significant difference in the incidence or size of bruises and pain perception the subject among techniques. Results of the study show that use of air lock technique without aspiration and two-minute cold application to the area of injection with methods reduce bruise and pain.

A study on the effect of the duration of subcutaneous heparin injection on bruising and pain

AIM

This study was carried out to determine the effect of injection duration on bruising and pain following the administration of the subcutaneous injection of heparin.

BACKGROUND

Although different methods to prevent bruising and pain following the subcutaneous injection of heparin have been widely studied and described, the effect of injection duration on the occurrence of bruising and pain is little documented.

DESIGN

This study was designed as within-subject, quasi-experimental research.

METHOD

The sample for the study consisted of 50 patients to whom subcutaneous heparin was administered. Heparin was injected over 10 seconds on the right abdominal site and 30 seconds on the left abdominal site. Injections areas were assessed for the presence of bruising at 48 and 72 hours after each injection. Dimensions of the bruising on the heparin applied areas were measured using transparent millimetric measuring paper. The visual analog scale (VAS) was used to measure pain intensity and a stop-watch was used to time the pain period. Data were analysed using chi-square test, Mann-Whitney U, Wilcoxon signed ranks tests and correlation.

RESULTS

The percentage of bruising occurrence was 64% with the injection of 10 seconds duration and 42% in the 30-second injection. It was determined that the size of the bruising was smaller in the 30-second injection. Pain intensity and pain period were statistically significantly lower for the 30-second injection than for the 10-second injection.

CONCLUSIONS

It was determined that injection duration had an effect on bruising and pain following the subcutaneous administration of heparin. This study should be repeated on a larger sample.

RELEVANCE TO CLINICAL PRACTICE

When administering subcutaneous heparin injections, it is important to extend the duration of the injection.

Effects of injection duration on site-pain intensity and bruising associated with subcutaneous heparin

AIM

The research evaluated two subcutaneous heparin injection techniques to determine the effects of different injection duration (10- and 30-seconds) on site-pain intensity and bruising.

BACKGROUND

The research was instigated because nurses and patients in the hospital under investigation reported a high incidence of site-pain and bruising associated with subcutaneous heparin therapy. This research was conducted over a period of 7 months between September 1998 and April 1999. The Ethic Committees of the University and the hospital approved the research.

METHODS

The research used a within-subjects, quasiexperiment, which would yield more convincing causal inferences, owing to the assumption that pain perception and physiological factors affecting coagulation varied less in the same subject than in two comparable subjects. The research involved 34 stroke patients receiving low-molecular weight heparin. For each subject, one of the two injection techniques was used as the first injection and 12 hours later the other injection technique as the second injection. Subjects rated the level of perceived site-pain intensity using the vertical visual analogue scale (VAS). Injection-site bruising were measured at 48 and 60 hours after each injection. Digital planimetry was used to measure the surface-area of bruise tracings. The final data set for analysis consisted of 68 VAS pain scores and 136 bruise sizes. As normality of the data could not met after transformations, Wilcoxon Signed-Rank tests were used to determine the effects caused by injection duration on site-pain and bruise size. The level of significance was determined at P < 0.05.

RESULTS

Results indicated that the 30-second duration injection technique resulted in significantly less intense site-pain and fewer and smaller bruises.

CONCLUSIONS

It was concluded that administering a subcutaneous heparin injection over longer duration reduces injection site-pain and bruising. However, the convenience, relatively small sample may limit the generalisability of the research findings.