Overview
Definition:
Central venous catheter (CVC) insertion is a medical procedure to place a catheter into a large vein, typically in the neck, chest, or groin, to administer fluids, medications, nutrition, or to monitor hemodynamic parameters
The subclavian approach involves cannulation of the subclavian vein, a large vein located beneath the clavicle.
Epidemiology:
Central venous catheters are used in a significant percentage of hospitalized patients, particularly in intensive care units and during major surgeries
The subclavian approach is a common method, though its incidence varies based on institutional protocols and patient factors.
Clinical Significance:
Subclavian CVC insertion is crucial for managing critically ill patients requiring long-term venous access, fluid resuscitation, vasopressor therapy, chemotherapy, or total parenteral nutrition
Proficiency in this technique is essential for surgical residents to provide safe and effective patient care and is a frequent topic in DNB and NEET SS examinations.
Indications
Major Indications:
Need for long-term intravenous access
Administration of vesicant chemotherapy or irritant medications
Hemodynamic monitoring (e.g., central venous pressure)
Administration of total parenteral nutrition (TPN)
Rapid fluid resuscitation
Plasmapheresis or hemodialysis access.
Specific Situations:
Patients with difficult peripheral venous access
Emergent situations requiring large-bore venous access
Procedures necessitating internal jugular or femoral vein avoidance due to thrombosis or infection.
Contraindications:
Absolute contraindications include severe coagulopathy or thrombocytopenia (relative contraindication), infection at the insertion site, ipsilateral subclavian vein thrombosis or occlusion, and a history of thoracic surgery or radiation on the side of insertion
Congenital absence of the clavicle.
Preoperative Preparation
Patient Assessment:
Assess patient's coagulation status (PT/INR, aPTT, platelet count)
Review previous thoracic imaging for anatomical anomalies or pathology
Obtain informed consent detailing the procedure, risks, benefits, and alternatives.
Equipment Checklist:
Sterile drapes, gown, gloves, mask, and eye protection
Antiseptic solution (e.g., chlorhexidine)
Local anesthetic (lidocaine 1-2% with epinephrine)
CVC kit (including guidewire, dilator, catheter, introducer needle)
Ultrasound machine with sterile probe cover and gel
Sterile dressing supplies
Suture material (e.g., 3-0 silk or nylon)
ECG monitor.
Patient Positioning:
Place the patient in a supine position with a slight Trendelenburg tilt (10-15 degrees) to increase venous pressure and reduce air embolism risk
Place a rolled towel or sandbag beneath the ipsilateral shoulder to accentuate the subclavian space
Identify anatomical landmarks: clavicle, sternal notch, acromion.
Procedure Steps
Landmark Identification:
Palpate the clavicle and the suprasternal notch
The insertion point is typically 1-2 cm inferior to the midpoint of the clavicle, aiming towards the ipsilateral sternoclavicular joint.
Aseptic Technique:
Perform a maximal sterile barrier precautions: hand hygiene, sterile gown, gloves, mask, and cap
Prepare the skin with antiseptic solution in a circular motion from the intended insertion site outwards
Allow the antiseptic to dry completely.
Anesthesia And Insertion:
Infiltrate local anesthetic into the skin and subcutaneous tissue at the insertion site and along the intended path of the needle
Insert the introducer needle at a 15-30 degree cephalad angle, aiming towards the sternoclavicular joint
Slowly withdraw the needle
pulsatile bright red blood indicates arterial puncture (stop and apply pressure)
Aspiration of dark, non-pulsatile venous blood signifies successful venous entry.
Guidewire Placement:
Once venous blood is aspirated, advance the flexible tip of the guidewire through the introducer needle into the subclavian vein
Remove the introducer needle, leaving the guidewire in place
If resistance is met, do not force the guidewire
reposition and re-evaluate.
Catheter Advancement And Securing:
Thread the dilator over the guidewire to enlarge the tract
Remove the dilator, leaving the guidewire
Advance the CVC over the guidewire until the hub is at the skin insertion site
Remove the guidewire
Connect syringes to the catheter lumens and aspirate blood to confirm venous patency and rule out arterial placement
flush each lumen with heparinized saline.
Dressing And Confirmation:
Secure the catheter at the skin insertion site with sutures and apply a sterile transparent dressing over the insertion site and the catheter hub
Obtain a post-procedure chest X-ray to confirm tip placement in the superior vena cava and rule out pneumothorax or hemothorax.
Postoperative Care
Monitoring:
Continuous ECG monitoring for arrhythmias
Vital sign monitoring, including blood pressure and heart rate
Assess for signs of pneumothorax, hemothorax, or subcutaneous emphysema
Monitor insertion site for bleeding, leakage, or signs of infection.
Catheter Care:
Regular flushing of catheter lumens with heparinized saline according to institutional protocol to maintain patency
Strict aseptic technique during all manipulations of the catheter
Proper dressing changes as per protocol.
Line Duration:
The duration of catheter use depends on the clinical indication
Long-term catheters (e.g., tunneled catheters, PICCs) are preferred for extended therapy to reduce infection risk
Daily reassessment of the need for the catheter is crucial.
Complications
Early Complications:
Pneumothorax: air in the pleural space, leading to lung collapse
requires chest tube insertion
Hemothorax: blood in the pleural space, a surgical emergency
Arterial puncture: can lead to hematoma, pseudoaneurysm, or arteriovenous fistula
requires immediate pressure application
Air embolism: air entering the venous circulation, potentially causing stroke or cardiac arrest
managed by Trendelenburg position and 100% oxygen
Cardiac tamponade: rare, but can occur with perforation of the heart or great vessels.
Late Complications:
Catheter-related bloodstream infection (CRBSI): serious complication requiring catheter removal and antibiotics
Thrombosis: clot formation within the vein or at the catheter tip, leading to venous obstruction
Catheter occlusion: blockage of catheter lumens
Migration of the catheter tip: can lead to arrhythmias or perforation.
Prevention Strategies:
Adherence to maximal sterile barrier precautions during insertion
Use of ultrasound guidance for insertion
Careful anatomical landmark identification and needle advancement angle
Prompt recognition and management of arterial puncture
Daily assessment of the need for the catheter
Meticulous catheter care, including proper flushing and dressing changes
Education of healthcare providers on sterile techniques and early complication recognition.
Key Points
Exam Focus:
Comprehend the indications, contraindications, and absolute contraindications for subclavian CVC insertion
Master the anatomical landmarks and insertion technique, including the correct needle angle and aspiration findings
Recognize and manage immediate complications like pneumothorax and arterial puncture
Understand the principles of sterile technique and infection prevention.
Clinical Pearls:
Always use ultrasound guidance if available, especially in novice operators, to improve success rates and reduce complications
A small amount of blood in the syringe when aspirating from the introducer needle may indicate proximity to the vein, allowing for subtle needle adjustments
If arterial blood is aspirated, apply firm, direct pressure to the insertion site for at least 5-10 minutes, and monitor for hematoma formation
A post-insertion chest X-ray is mandatory to confirm tip position and rule out complications.
Common Mistakes:
Failure to adhere to maximal sterile barrier precautions
Incorrect anatomical landmark identification leading to arterial puncture or malposition
Forcing the guidewire, which can cause vessel perforation or dislodgement
Inadequate flushing leading to catheter occlusion
Delayed recognition or management of complications like pneumothorax.