Subcutaneous and Intramuscular Injection

SUBCUTANEOUS AND INTRAMUSCULAR INJECTIONS

The Irish physician Francis Rynd (1811–1861) invented the hollow needle in 1844,
patented in the Irish patents office. Charles Gabriel Pravaz (1791–1853), a French
physician, created the first hypodermic tubular needle and syringe in 1853, made
entirely from silver. Soon after, the Scottish physician Alexander Wood (1817–1884)
went on to develop a method for subcutaneous injection. Not without an unfortunate
sense of irony, the first recorded fatality from an overdose administered by Wood’s
invention was that of his wife who had become addicted to intravenous morphine.
INTRODUCTION
Subcutaneous and intramuscular injections provide routes for medication delivery that
do not require intravenous access. This may be advantageous in either an emergency
situation (e.g. intramuscular epinephrine) or electively (e.g. subcutaneous insulin).
INDICATIONS
Subcutaneous injections, e.g. insulin, tetracosactide, growth hormone, morphine
Intramuscular injections, e.g. haloperidol, epinephrine, metoclopramide, cyclizine.
CONTRAINDICATIONS
• Local contraindications to injection include:
— cellulitis
— haematoma


— lipoatrophy
— lipohypertrophy
— lymphoedema.
• Bleeding diatheses – coagulopathy or thrombocytopaenia may increase the risk of 
subcutaneous or intramuscular haematoma formation.
• Lack of consent.
EQUIPMENT
•Gloves.
• Sterile hypodermic needles 
— 25 gauge needle (orange: length 16 mm, inner diameter 0.241 mm) for subcutaneous delivery
— 21 gauge (green: length 40 mm, inner diameter 0.495 mm) to 23 gauge needle 
(blue: length 30 mm, inner diameter 0.318 mm) for intramuscular delivery
— 21 gauge needle for drawing up the drug.
• Syringe (of required volume for the medication +/– volume of dilutant required to 
reconstitute the medication).
•Sterile alcohol swabs.
•Gauze.
•Plaster.
•Vial of medication to be administered. Always read the instructions to check the 
correct dosage, route of delivery and solution required to reconstitute the powder 
form of the medication.
•Sharps bin.
PRACTICAL PROCEDURE
PREPARATION
•Explain the procedure to the patient and gain consent.
• Position the patient and expose the area for injection.
•Wash your hands and wear gloves.
• Perform the following checks prior to administering any medication:
— Confirm the patient’s personal details and check that they correspond with their 
drug chart and name band.
— On the drug chart confirm the patient’s drug allergies, the drug to be given, the 
dose required, the timing of the dose and the route of administration.
— Check the drug itself together with the dosage and expiry date in the presence 
of a colleague.
• Draw up the required volume of specified dilutant (see information accompanying 
the medication) into the syringe using a green needle.
•Open the vial of medication for injection. Insert the syringe containing the dilutant 
attached to the green needle. Insert a second green needle into the vial to allow air 
to escape when adding dilutant.
• Reconstitute the medication in the vial and aspirate into the syringe when complete. Discard the vial and green needles into a sharps bin.
•Expel any excess air or air bubbles from the syringe by gently tapping the side of 
the syringe whilst holding it upright.
•Clean the area of skin for injection with sterile alcohol swabs and allow to dry.
SUBCUTANEOUS INjECTION
•Attach the 25 gauge (orange) needle to the syringe.
•Choose a site for injection. Suitable sites include the triceps area, anterior thigh 
area or the abdomen.
• Pinch and lift the skin overlying this area gently into a fold between the thumb 
and index finger of your non-dominant hand, thereby separating the subcutaneous 
adipose tissue layer from the muscle 
• Warn the patient of a sharp scratch.
• Gently insert needle into the skin at a 30–45 degree angle.
•Slowly inject the medication.
INTRAMUSCULAR INJECTION
•Attach the 23 gauge (blue) or 21 gauge (green) needle to the syringe.
• Choose a site for injection taking into account the individual’s muscle mass. Suitable muscles include the deltoids, the gluteal muscles and the lateral thigh muscles.
•Pull the skin taught over the underlying muscle layer and insert the needle in one 
swift motion.
Pinch and lift the skin into a fold, separating the subcutaneous adipose tissue 
layer from the muscle.
• Aspirate the syringe to ensure that the needle is not in a blood vessel.
• Slowly inject the medication at a rate of approximately 1 mL every 10 seconds. 
FINISHINGOFF
• Remove the needle and apply pressure to the puncture site with gauze or cotton 
wool to prevent haematoma formation.
•Dispose of the syringe and needle into a sharps bin.
•Attach a plaster if needed.
•Observe for any adverse drug reactions.
•Record the date and time of injection on the patient’s drug chart.
COMPLICATIONS
•Local infection – either superficial (cellulitis) or deep (abscess formation).
•Bleeding – either superficial or deep haematoma formation. This may predispose to 
infection.
• Lipoatrophy.
•Lipohypertrophy.
•Injection fibrosis – if injections are delivered with an incorrect technique or too 
frequently to that site.

Nasogastric tube insertion

                                       Nasogastric tube Insertion

 The modern nasogastric (NG) tube is a 1921 modification by John Alfred Ryle (1889–1950). He covered the tip of the NG tube with rubber to prevent injury to the gastric mucosa, unlike previous tubes which had a metal bulb at their tip. However, the earliest recording of using a tube for enteral nutrition was that of the Seville-born Arab surgeon Ibn Zuhr (also known as Avenzoar, 1091–1161) who fed a patient with an oesophageal stricture via a silver tube. Incidentally Ibn Zuhr is also credited with the first correct description of performing a tracheotomy for suffocating patients. 
INTRODUCTION 
Nasogastric tube placement is a simple procedure, but can be unpleasant for the conscious patient. This is commonly performed by nursing staff; however, junior doctors would be expected to place them if these initial attempts are unsuccessful. Small-diameter (8–12 Fr) tubes are frequently used for patents who require enteral feeding. Larger tubes (14 Fr or larger) are used to administer medications, provide gastric decompression or allow continuous aspiration of retained gastric contents. These larger tubes are acceptable for feeding over a short period, usually less than 1 week. Small-bore NG tubes cause less trauma to the nasal mucosa both during insertion and while in situ, and are better tolerated. Placement errors lead to potentially major complications, most commonly when mistakenly placed in the respiratory tract. Failure to observe pathological states that constitute a contraindication to NG tube placement can result in passage of the tube into the brain (base of skull fracture) or peritoneum (upper GI perforation).
 INDICATIONS 
wide bore nasogastric tubes •(Bowel obstruction. • Gastric outlet obstruction.)fine bore nasogastric tubes (• Enteric feeding. )
CONTRAINDICATIONS
 • Coagulopathy (a relative contraindication). • Oesophageal varices. • Maxillofacial and oropharyngeal trauma or surgery. • Skull fractures. • Unstable cervical spine injury. • Laryngectomy. • Compromised airway. 
EQUIPMENT 
• Sterile gloves. • Kidney bowl. • Gauze. • Lubricant jelly. • NG tube. • 10 mL syringe. • Litmus paper. • Medical adhesive tape. • Drainage bag. • Gloves. • Glass of water with straw. 
PRACTICAL PROCEDURE
 • Explain the procedure to the patient and obtain consent. • Wash your hands and wear sterile gloves. • Ensure that the end of the NG tube will fit the drainage bag to be used.• The patient should be in an upright position, the head supported with pillows if needed to ensure that it is not tilting backwards. • Check the patency of the nostrils; ask the patient to blow their nose if needed. • Lubricate the NG tube tip and the first 10 cm. • Slowly insert the NG tube into a nostril using a rotating motion and advance it horizontally along the base of the nasal cavity until it reaches the posterior pharynx (and hence usually induces the gag reflex). • Ask the patient to swallow water repeatedly through a straw whilst advancing the NG tube during the swallow. In this manner the patient effectively swallows the tube into the oesophagus. • Advance the NG tube down the oesophagus and into the stomach . The NG tube is graduated every 10 cm (usual mouth to stomach distance is 35–40 cm). Hence insert the NG tube to the 40 cm mark. cm mark. • Ensure the NG tube is sitting in the stomach: — Gently aspirate stomach contents with a syringe and test with litmus paper (if in the stomach the pH should be less than 4).When the nG tube is in the pharynx, rotate the tube 180 degrees to encourage passage of the tube into the oesophagus rather than the trachea. this is especially useful if the tube has been refrigerated, making it more rigid.  if you are having trouble passing the nG tube, try asking the patient to put their chin to their chest and insert the tube as above until it reaches the posterior pharynx.  if you are experiencing trouble passing the tube into the oesophagus because it is too soft and it keeps folding on itself in the back of the throat, try putting the tube in the fridge for 20 minutes for it to harden, or consider a larger tube.  inhibitors, antacids and H 2 antagonists may have a high gastric pH and hence aspiration tests may not be accurate. X-ray confirmation may have to be used in these patients. — Small-bore NG tubes commonly do not allow aspiration of stomach contents and require chest X-ray confirmation of position. — If you are unable to get adequate stomach contents to test for pH, the patient will need to have a chest X-ray to check the position of the tube. The tip of the tube must be seen to be below the diaphragm. • Attach the drainage bag. • Secure the NG tube around the patient’s nose with micropore tape taking care not to exert too much pressure on the nares adjacent to the NG tube. • Document the date and time of NG tube insertion. Document the type of tube inserted, the batch number, any complications or difficulties in insertion and how the correct position of the tube was confirmed. End of nasogastric tube Nasal cavity Trachea Pharynx Nasogastric tube Oesophagus 35–40cm Stomach insert the nasogastric tube to 40 cm as a guide to siting the tip in the stomach.
POST-PROCEDURE INVESTIGATIONS
 • If you are in any way unsure about the position of the NG tube, obtain a chest X-ray. The NG tube tip has a radio opaque line at the end and can therefore be seen. However, this X-ray confirmation is valid only at the time of the X-ray. • The NG tube should not be used until positive evidence of its placement has been obtained (pH or chest X-ray). • Syringing air down the NG tube whist auscultating the epigastrium is an unreliable method of checking tube position due to transmitted lung sounds.
 COMPLICATIONS
 • Failure to pass the NG tube. • Epistaxis. • NG tube passed into trachea. • Oesophageal, pharyngeal or gastric perforation. • NG tube in duodenum – should this be confirmed on chest X-ray pull the tube back approximately 5 cm. • Oesophagitis and stricture formation secondary to oesophageal inflammation. • Retropharyngeal or nasopharyngeal necrosis. • Sinusitis from NG tube in situ for a prolonged period of time.

Surgery instruments

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