Intra- vs intermuscular injections in swine

Transcription

1 Intra- vs intermuscular injections in swine P Houpert, H Combrisson, S Le Nain, A Autefage, Pl Toutain To cite this version: P Houpert, H Combrisson, S Le Nain, A Autefage, Pl Toutain. Intra- vs intermuscular injections in swine. Veterinary Research, BioMed Central, 1993, 24 (3), pp <hal > HAL Id: hal Submitted on 1 Jan 1993 HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

2 Original article Intra- vs intermuscular injections in swine P Houpert H Combrisson S Le Nain A Autefage PL Toutain 1 École Nationale Vétérinaire dalfort, 7, avenue du Général-de-Gautie, Maisons-Alfort, 2École Nationale Vétérinaire de Toulouse, 23, Chemin des Capelles, Toulouse, France (Received 9 September 1992; accepted 17 November 1992) Summary &horbar; In order to determine the exact localization (intra- vs intermuscular) in which a drug is injected when administered by a so-called intramuscular injection technique, a radiopaque test article (2 ml) was injected into the cervical musculature (2 sites), the loins and the gluteal mass in anaesthesized pigs. Immediately after this, the pigs were euthanized and deep-frozen. Then they were cut into slices, which were X-rayed to determine the exact localization of the test material. Semiquantitative scores were given to each injection site according to the amount of test article found in or out of muscle mass and also to the absence or the presence of test article subcutaneously. The loins area obtained the highest score for intramuscular location, but in this site, injections were almost always followed by a flowing back of the test article to the subcutaneous area. It was shown that an injection in the neck perpendicular to the skin surface just behind the base of the ear was the most appropriate site for intramuscular injection in pigs. pig I intrasmucular injection I intermuscular injection Résumé &horbar; Injections intra- ou intermusculaires chez le porc. Afin de préciser la localisation exacte des injections dites «intramusculaires» (intra- ou intermusculaire), un produit radio-opaque (2 ml) a été injecté dans la musculature cervicale (2 sites), les lombes et la masse glutéale (fessiers) chez des porcs anesthésiés. Les animaux ont été immédiatement euthanasiés, congelés et découpés en tranches. La radiographie des tranches a permis de caractériser la localisation exacte du matériel injecté (dans la masse musculaire on entre les faisceaux musculaires). Des évaluations semi-quantitatives ont été réalisées pour chaque site injecté selon la répartition du produit radioopaque. La région lombaire a obtenu le plus haut score pour la localisation strictement intramusculaire, bien que ce site d injection soit accompagné d un reflux du produit en zone sous-cutanée. Il a été montré que l injection dans l encolure, perpendiculairement à la peau, juste en arrière de la base des oreilles, était le site le plus approprié pour réaliser une injection authentiquement intramusculaire lorsque le volume à injecter est faible. porclinjection intramusculairelinjection intermusculaire * Correspondence and reprints

3 INTRODUCTION Anaesthesia and euthanasia In veterinary practice, many drugs are administered via the intramuscular (IM) route. This technique, easy to carry out, is performed following recommendations which owe more to habit than to any rigorous survey of its performances. Pharmacokinetic studies (Marshall and Palmer, 1980; Firth et al, 1986) (Hartman, 1985), local tolerance studies (Oshida et al, 1979) and studies of residue depletion at the injection site showed that the results obtained via the IM route were dependent on many factors, including the anatomic site of injection. Data obtained from the horse (Boyd, 1987) and the dog (Autefage et al, 1990) suggest that to obtain a strict IM localization of the deposit, it is necessary to select an anatomic site constituted of important muscular masses, rather than a site made up of small fascicules of muscle fibers. In swine, for obvious economic reasons, therapeutic drugs and vaccines are only administered in the neck region via socalled intramuscular injections. Considering the anatomy of the neck region (small fascicules of muscle fibers), there is no proof that these injections are really IM. The aim of this work was to determine the exact area of the deposit of a test material after its loins and gluteal mass, according to different techniques of injection likely to be used in pig practice. IM injections in the neck, MATERIALS AND METHODS Animals Two groups of 4 healthy Landrace pigs weighing 24.7 ± 2.1 kg and 92.7 ± 6.2 kg respectively were used. After an 18-h starvation period, the pigs were anaesthesized with sodium penthiobarbital (20 mg/kg bw). Then the animals were laid out on a table in ventral decubitus, the forelimbs stretched out in front of them, and the hindlegs under the body. They were kept in this position until their sacrifice, immediately after the injections of the test article. Sacrifice was carried out via the IV or intracardiac route with sodium penthiobarbital. The time between the beginning of the test material injections and death never exceeded 3 min. After death, the pigs were frozen at -20 C. Test article administration The test article was iohexol (Omnipaque 300 TM Winthrop, Clichy, France) a non-ionic, hydrosoluble, triiodate contrast product. The injection sites were marked out on both sides of the neck (2 sites), in the loins (1 site) and in the gluteal muscles (1 site) (see figs 1, 2). The anatomic marks chosen were the base of the ear and the dorsal spine for the injections in the neck, the dorsal spine and the iliac spine for the injections in the loins and in the gluteal mass. The injections (2 ml) were performed with hypodermic needles (21 gauge, 30 or 40 mm long); in the loins and in the gluteal area, they were carried out perpendicularly to the skin surface, and in the neck, they were given horizontally or vertically; for each injection, the needle was connected to a 2-mi syringe. Needles of 30 mm in length were used for the right side of the pigs 1, 2, 6 and 7 and for the left side of the pigs 3, 4, 5 and 8; needles 40 mm in length were used for the other side. Injections were given simultaneously on both sides by 2 different operators from the frontal neck to the gluteal site. Radiography and scoring After the animals were deep-frozen, they were cut with a bandsaw 1 or 2 cm from each injection site into slices 2 to 4 cm thick, each containing the contrast product. These slices were then X-rayed (T-Mat-G films, Kodak 30/40) and the

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5 results were then read by a single operator (AA). For each injection site, it was determined if the contrast product was to be found in the inter- or the intramuscular zone, in the subcutaneous region, in the fatty tissue or in any other anatomic site. All results were quantified using a semi-quantitative scoring system with 0 = absence of contrast product intramuscularly (ie strictly intermuscularly) 1 = less contrast product intramuscularly than intermuscularly; 2 = more contrast product intramuscularly than intermuscularly; and 3 = absence of contrast product intermuscularly (ie strictly intrasmucularly); the localization of contrast product subcutaneously was scored as 0 = absence and 1 = presence of test article. Statistics The results were statistically analyzed using a program (Statgraphics, STCS Inc, USA, 1988). Analysis of variance was performed. The intraor intermuscular localization score was the variable, the covariable was the pig s weight and the controlled factors were the localization of the injection sites, laterality and needle length. RESULTS Figure 3 shows an intramuscular localization of the contrast product flowing back to the subcutaneous level after an injection in the loins region. Figure 4 shows an intermuscular localization of the contrast product following an injection in the gluteal mass. Figure 5 shows both intra- and intermuscular localizations following an injection in the neck. The semi-quantitative scores are given in table I. Analysis of variance showed that the pig s weight (20 vs 80 kg), the length of the needle (30 vs 40 mm), the operator performing the injection (right vs left) do not significantly influence the test product deposit (P > 0.05). In contrast, the injection site had a significant effect (P < 0.05). Injection sites were graded in order of mean score (0 to 3 ± SD), which expresses the absence or the entire presence of the product intramuscularly. Results were as follows: frontal neck site with vertical nee-

6 dle (0.875 ± 1.25), rear neck site with vertical needle (1.13 ± 0.99), gluteal mass (1.80 ± 1.52), rear neck site with horizontal needle (1.88 ± 1.13), frontal neck site with horizontal needle (2.0 ± 1.15), loins region (2.63 ± 0.81 ). The occurrence of flowing back to the subcutaneous level was scored separately. Out of 32 injections in the neck, only 2 flowed back to the subcutaneous level, whereas this was observed in 13 out of 16 cubes in the loins, and in 6 out of 16 cases in the gluteal mass (table I). DISCUSSION Books on porcine pathology recommend injecting intramuscularly but do not specify any particular technique (eg Kunesch, 1981). Injection sites in this study were chosen with respect to farm animal practice (neck) and to some experimental procedures (gluteal muscles). The loins and the gluteal area are not used in practice, but in some pharmacokinetic and residue depletion studies (gluteal mass), and particularly to determine the withdrawal period. This is due to the fact that the neck is considered a difficult area to reidentify the injection sites, and so makes the taking of muscle samples for analytic examination somewhat arbitrary. This practice raises the problem of the legitimacy of extrapolating from the gluteal mass to the neck region and more generally it is necessary to know whether these injections are intramuscular or not. The volume of radiopaque product injected (2 ml), was selected both for technical and biological reasons. This volume is sufficient to allow for a correct visualization

7 of the product on the radiographs, and it resembles that of common vaccines (Aujeszky: 2 ml; foot and mouth disease: 1 ml) or of some widely-used therapeutic agents (Carazolol: a [3-blocking agent). On the other hand, many widely used drugs like antibiotics or antiinflammatory drugs are administered in much more important volumes, and it is by no means certain that the results of this trial may be directly applicable to these drugs. The weight of the animals does not influence the localization of the deposit, certainly because of the small volume administered. For larger volumes, there would probably be some effect. Injection site was the only parameter found to influence significantly the localization of the deposit. The 2 sites giving the highest percentages of intramuscular injections are the loins and the neck when the injection is given horizontally, just behind the base of the ear and a hand s width from the spine (site 1, fig 1). This technique is generally recommended in practice, and this study supports its usefulness. The site offering the lowest percentage of intramuscular injections is also in the neck (frontal site, vertical injection, site 1; fig 2), which proves the extreme importance of a correct injection technique (location, restraining) to obtain a real intrasmucular injection in the neck. With the 2-mi volume used in this study, no differences due to the length of the nee-

8 dle were shown. This does not support the notion of so-called deep intramuscular injection; however, differences could perhaps have been demonstrated with larger volumes. All the injections on the same side were performed by the same operator, so this factor was added to that of laterality (no significance). The results obtained in this study demonstrate clearly the influence of injection site on the occurrence of the product at the subcutaneous level: this phenomenon almost always follows the injections in the loins, whereas only 2 out of 32 injections in the neck show the same results. This difference could be attributed to the size of the muscles, and the elasticity of their environment. In the loins, muscles are large and compact, and as the needle has a large diameter, the flow is rapid. So, the product runs along the outside of the needle to a less resistant area, either to a cleavage plan between muscles or, failing that, to the subcutaneous tissue, where it

9 spreads out. In the neck, the muscles are smaller and surrounded by loose conjunctive tissue: when the product comes out of the needle, it succeeds in distending and separating the muscles, and prevents the product from flowing. A subcutaneous leakage from an injection site must be avoided, because it may cause important and visible local inflammatory reactions. The use of thinner needles could reduce such a phenomenon, but is not suitable for practice, as the increase in the risk of breaking them in the animals would become too high. Finally, the injection site influences the results both in the distribution of the product between the intra- and the intermuscular areas, and in the occurrence of subcutaneous leakage. The best injection site in swine for a volume of 2 ml was found to be a horizontal injection in the neck, just behind the base of the ear and a hand s width from the spine, which is also in accordance with practical requirements. ACKNOWLEDGMENT Financial support for this study was supplied by Pfizer Animal Health Co. REFERENCES Autefage A, Fayolle P, Toutain PL (1990) Distribution of material injected intramuscularly in dogs. Am J Vet Res 51, Boyd JS (1987) Selection of sites for intramuscular injections in the neck of the horse. Vet Rec121, Firth EC, Nouws JFM, Driessens F, Schaetz P, Klein WR (1986) Effect of the injection site on the pharmacokinetics of procaine penicillin in horses. Am J Vet Res 47, Hartman EG (1985) Influence of the injection site on the depot effect of procaine penicillin in dogs. In: Comparative Veterinary Pharmacology, Toxicology and Therapy (Van Miert ASJ- PAM, Bogart MG, Debackere M, eds) Proc 3rd Congr Eur Assoc Vet Pharmacol Toxicol. August 25-29, Ghent, Belgium, Kunesh JP (1981) In: Diseases of Swine (Leman AD, Straw B, Glock RD, Mengeling WL, Penny RHC, Scholl F, eds) The Iowa State University Press, IA, 5th edn, Marshall AB, Palmer GH (1980) Injection sites and drug bioavailability. In: Trends in Veterinary Pharmacology and Toxicology (Van Miert ASJPAM, Frens J and Kreek FW, eds) Elsevier Sci Publ, Amsterdam, Oshida S, Degawa K, Takahashi Y, Akaishi S (1979) Physico-chemical properties and local toxic effects of injectables. Tohoku J Exp Med 127,