Tag Archives: vascular access


Externally rotate leg for femoral vein access

Want to access the femoral vein? Externally rotate the leg at the hip and things might be a bit easier. This study was done in adult patients, with the knee straight and no abduction applied. External rotation is also helpful in kids, with abduction up to sixty degrees.


Objective: To determine if external rotation of the leg increases the size and accessibility of the femoral vein compared with a neutral position.

Methods: One hundred patients presenting to a tertiary teaching hospital were prospectively recruited. The right common femoral vein of each subject was scanned with a linear probe (5–10 MHz) inferior to the inguinal ligament, with the leg in a neutral position and then in the externally rotated position. The transverse diameter of the femoral vein, the accessible diameter of the vein (lying medial to the femoral artery) and the depth of the vein were measured.

Results: The mean diameter of the femoral vein in the externally rotated leg was greater than with the leg in the neutral position (15.4 mm vs 13.8 mm); the mean difference was 1.6 mm (95% CI 1.3–1.9). The mean accessible diameter of the femoral vein was larger with the leg externally rotated (13.8 mm vs 11.7 mm, mean difference 2.1 mm, 95% CI 1.8–2.5). The depth from the skin to the femoral vein was less with the leg in external rotation (20.9 mm vs 22.6 mm, mean difference 1.7 mm, 95% CI 1.2–2.2). The mean diameter and depth were greater in patients with overweight or obese body mass index (BMI) measurements in both leg positions. The increase in femoral vein diameter and accessibility with external rotation was observed in all BMI groups.

Conclusion: The total and accessible femoral vein diameter is increased and the surface depth of the vein is decreased by placing the leg in external rotation compared with the neutral position.

Simple external rotation of the leg increases the size and accessibility of the femoral vein
Emerg Med Australas. 2012 Aug;24(4):408-13

Not a pin cushion

This is the daughter of my friend. Avery is only seven months old and has survived a critical illness and is thankfully now fully recovered. Her Dad has nothing but praise for the medical and nursing staff who cared for her. But one thing could have been better. Avery endured multiple attempts at vascular access without ultrasound guidance.

If you were her parent, and you were an emergency physician with galaxy-class expertise in emergency ultrasound, how would you react? Complaints? Incident forms? Outrage?

How about education? For free. Accompanied by lavish praise for the experts who treated Avery and made her better.

Avery’s Dad is ultrasound podcaster and gentleman Dr Matt Dawson. He is offering FREE ultrasound training to anyone who wants to improve their vascular access skills.

Are there nurses, physicians, or technicians in your ED or ICU that could improve their care with this training? Please consider sending them for this training. To register for the course, and to read Avery’s full story, go to notapincushion.com.

And if you’re already comfortable with ultrasound-guided vascular access, then visit the site anyway, as there is some education here for all of us: how to turn a gut-wrenchingly distressing experience into something positive that will benefit countless others. I am thoroughly inspired.

Best wishes to an amazing family.

Cliff

The REAL Shocked Patient

I promised to put some summary notes on the site for those who attended my talk on ‘The REAL Shocked Patient’ for the Australian College of Ambulance Professionals on Tuesday 21st February 2012, so here they are:

Shocked patients are important – they comprise most of the ‘talk and die’ caseload that preoccupies pub conversations between emergency physicians

It’s easy to mistake these patients as less sick than, say, hypoxic ones, but oxygen delivery to the tissues doesn’t just depend on oxygen!

Here’s a dead wombat – someone in the audience knew a worrying amount about wombat anuses.

The 4 Hs and 4 Ts aren’t a very cognitively practical mnemonic for the causes of PEA arrest (which is an extreme form of hypotension)

I prefer the ‘3 plus 3’ rule, which breaks down the causes into three – volume, pump, and obstruction. Obstruction is further broken down into three causes, being tension pneumothorax, cardiac tamponade, and pulmonary embolism:

Let’s look at some cases of shock caused by volume deficit, pump falure, or one of the three causes of obstruction to the circulation:

 

Case 1: The hypotensive motorcyclist
His low back pain suggested pelvic fracture
Think of ‘blood on the floor and four more’ (chest, abdomen, pelvis/retroperitoneum, long bones) and consider non-bleeding causes such as neurogenic (spinal injury), tension pneumothorax, cardiac tamponade, and finally medical causes/iatrogenic (drug) causes.
Don’t underestimate the importance of pelvis and limb splinting as a haemorrhage control technique in blunt trauma
Ultrasound in flight made thoracic or abdominal bleeding very unlikely, and ruled out tamponade and pneumothorax

Although he was hypotensive, no fluids were given, as he was mentating normally and peripherally well perfused, with a radial pulse. If we gave fluid, we would titrate to the presence of a radial pulse (in blunt trauma) but we don’t want to ‘pop the clot’ by elevating the BP, or make him less able to form effective clots by diluting his blood with crystalloid.

Mortality in trauma sharply rises with systolic BP below 105-110, so recalibrate your definition of hypotension in terms of when you might be concerned, and which patients may benefit from triage to a trauma centre.

 

Case 2: The child crushed by a wall
Caution regarding lower limb infusions in patients with abdominal / pelvic injuries – the fluid may not get to the heart.

The classification of shock into four classes is crap. Never let the absence of a tachycardia reassure you.

Intraosseous is awesome, and EZ-IO has the best track record by far.

 

Case 3: The boy stabbed in the upper thigh
In penetrating limb trauma, prehospital options include pressure, elevation, tourniquet, and haemostatic dressings. Foley catheters have been used successfully in transition zones such as the neck or groin.

 

Case 4: Haematemesis
Should we apply the same principles of permissive hypotension to patients with ‘medical’ bleeding?
The Trendelenburg position doesn’t make a lot of sense – no need to head down the patient, although the act of elevating the legs may ‘autoinfuse’ a bolus of blood to the core circulation, and is recommended by some bodies as a first aid manoeuvre for hypotensive patients in the field prior to iv fluids.

 

Case 5: The overdose patient with a low blood pressure but otherwise fine.
When don’t I Worry about hypotension? When the patient is:

  • With it
  • Warm peripherally
  • Weeing
  • and (in hospital) Without a raised lactate


Case 6: Two cases of pump failure: STEMI and complete heart block
Adrenaline infusions can be simply made with a 1mg 1:10000 minijet diluted in a litre of saline and dripped through a peripheral line titrated to BP / HR / mentation / pulses.
In complete heart block (or other bradycardias) with hypotension, percussion pacing is an option of you don’t have access to transcutaneous or transvenous pacing. If you get capture, it’s as effective in terms of stroke volume as a pacing wire.

 

Case 7: Obstructive shock – tamponade cases
…with resolution of hypotension after drainage by emergency physicians who identified the tamponade on ultrasound, even though they didn’t suspect it clinically. It can be a surprise!

 

Case 8: Obstructive shock – tension pneumothorax
Patients are often agitated and won’t lie flat. They may complain of ‘tight’ breathing. Crackles and/or wheezes may be heard. The classic description of deviated trachea, absent breath sounds, and hyperresonance are the exception, not the rule. Be suspicious and always palpate for subcutaneous emphysema.
Don’t assume a needle decompression will work – there is debate about the best site but in some adults a standard needle won’t reach the pleural space. If you need to place more than one needle, go for it. As physicians, we do thoracostomies to ensure we’ve hit the spot.

 

Case 9: Obstructive shock – pulmonary embolism
A tough one prehospital, as the hypotensive ones need fibrinolysis. Fluid may help the hypotension but too much can overdistend the right ventricle which can then impair left ventricular filling, and worsen the patient’s circulatory state. Once again, ultrasound may be invaluable in highlighting PE as a possible cause for shock.

 

Case 10: Penetrating trauma to the ‘box’ – chest and upper abdomen.
If these patients arrest due to tamponade, early (< 10 minutes) clamshell thoracotomy can be life saving, which means it may need to be done pre-hospital by a HEMS physician to provide a chance of survival. Be on the look out for these and if in doubt activate a medical team (in New South Wales). Like with tension pneumothorax, these patients may be extremely agitated as a manifestation of their shock.

 

Case 11: Confused elderly male with pyrexia and smelly urine who appears ostensibly ‘normotensive’
…but how many 82 year olds do you know with a BP of 110/57? His acute confusion may be a manifestation of shock and he needs aggressive evaluation in hospital including a lactate measurement. Don’t be afraid to give this guy fluids in the field – you can make a big difference here.

Here are five of the myths I promised to expose:

So…shocked patients can talk and die. Don’t let that happen. Shocked patients can be normotensive, and hypotensive patients might not be shocked. Have a plan for how you might evaluate the 3+3 causes in your setting and what you can use from your medication and equipment list to manage volume, pump, and obstruction issues. You will save many lives if you become a serious shock detective.

PICCs more complicated than CVCs

A review showed that peripherally inserted central catheters were associated with higher rates of complications that standard central venous catheters



We undertook a review of studies comparing complications of centrally or peripherally inserted central venous catheters. Twelve studies were included. Catheter tip malpositioning (9.3% vs 3.4%, p = 0.0007), thrombophlebitis (78 vs 7.5 per 10 000 indwelling days, p = 0.0001) and catheter dysfunction (78 vs 14 per 10 000 indwelling days, p = 0.04) were more common with peripherally inserted catheters than with central catheter placement, respectively. There was no difference in infection rates. We found that the risks of tip malpositioning, thrombophlebitis and catheter dysfunction favour clinical use of centrally placed catheters instead of peripherally inserted central catheters, and that the two catheter types do not differ with respect to catheter- related infection rates.


Complications associated with peripheral or central routes for central venous cannulation
Anaesthesia. 2012 Jan;67(1):65-71

Ultrasound-Guided Radial Artery Catheterization

In case you needed some evidence – a systematic review supports ultrasound guidance as a means of improving insertion success of radial artery catheters



BACKGROUND: Ultrasound guidance commonly is used for the placement of central venous catheters (CVCs). The Agency for Healthcare Research and Quality recommends the use of ultrasound for CVC placement as one of its 11 practices to improve patient care. Despite increased access to portable ultrasound machines and comfort with ultrasound-guided CVC access, fewer clinicians are familiar with ultrasound-guided techniques of arterial catheterization. The goal of this systematic review and meta-analysis was to determine the utility of real-time two-dimensional ultrasound guidance for radial artery catheterization.


METHODS: A comprehensive literature search of Medline, Excerpta Medica Database, and the Cochrane Central Register of Controlled Trials by two independent reviewers identified prospective, randomized controlled trials comparing ultrasound guidance with traditional palpation techniques of radial artery catheterization. Data were extracted on study design, study size, operator and patient characteristics, and the rate of first-attempt success. A meta-analysis was constructed to analyze the data.


RESULTS: Four trials with a total of 311 subjects were included in the review, with 152 subjects included in the palpation group and 159 in the ultrasound-guided group. Compared with the palpation method, ultrasound guidance for arterial catheterization was associated with a 71% improvement in the likelihood of first-attempt success (relative risk, 1.71; 95% CI, 1.25-2.32).


CONCLUSIONS: The use of real-time two-dimensional ultrasound guidance for radial artery catheterization improved first-pass success rate.


Ultrasound-Guided Catheterization of the Radial Artery
Chest. 2011 Mar;139(3):524-9

Central lines in coagulopathic patients

If a patient needs a central line, he/she needs one. Often low platelets or a deranged coagulation profile are cited as reasons for omitting or delaying the procedure, but this is not based on evidence of increased complications. A recent Best Evidence Topic Review concludes:

…insertion of CVC lines do not require correction of haemostatic abnormalities prior to intervention. Rates of haemorrhage are low in patients with elevated PT, APTT or low thrombocyte count and appear to be closely related to the level of experience of the physician … rather than the defects of haemostasis.

Links to the abstracts of a couple of relevant articles reviewed are included below.

Central line insertion in deranged clotting
Emerg Med J. 2011 Jun;28(6):536-7 Full text

Low levels of prothrombin time (INR) and platelets do not increase the risk of significant bleeding when placing central venous catheters.
Med Klin (Munich). 2009 May 15;104(5):331-5

US-guided placement of central vein catheters in patients with disorders of hemostasis
Eur J Radiol. 2008 Feb;65(2):253-6

FAST 1 success rates in the field

Three quarters of attempts to place the FAST 1 sternal intraosseous device were successful…

Introduction: Access to the vascular system of the critically ill or injured adult patient is essential for resuscitation. Whether due to trauma or disease, vascular collapse may delay or preclude even experienced medical providers from obtaining standard intravenous (IV) access. Access to the highly vascular intramedullary space of long bones provides a direct link to central circulation. The sternum is a thin bone easily identified by external landmarks that contains well-vascularized marrow. The intraosseous (IO) route rapidly and reliably delivers fluids, blood products, and medications. Resuscitation fluids administered by IV or IO achieve similar transit times to central circulation. The FAST-1 Intraosseous Infusion System is the first FDA-approved mechanical sternal IO device. The objectives of this study were to: (1) determine the success rate of FAST-1 sternal IO device deployment in the prehospital setting; (2) compare the time of successful sternal IO device placement to published data regarding time to IV access; and (3) describe immediate complications of sternal IO use.

Methods: All paramedics in the City of Portsmouth, Virginia were trained to correctly deploy the FAST-1 sternal IO device during a mandatory education session with the study investigators. The study subjects were critically ill or injured adult patients in cardiac arrest treated by paramedics during a one-year period. When a patient was identified as meeting study criteria, the paramedic initiated standard protocols; the FAST-1 sternal IO was substituted for the peripheral IV to establish vascular access. Time to deployment was measured and successful placement was defined as insertion of the needle, with subsequent aspiration and fluid flow without infiltration.

Results: Over the one-year period, paramedics attempted 41 FAST-1 insertions in the pre-hospital setting. Thirty (73%) of these were placed successfully. The mean time to successful placement was 67 seconds for 28 attempts; three of the 31 insertions did not have times recorded by the paramedic. Paramedics listed the problems with FAST-1 insertion, including: (1) difficulty with adhesive after device placement (3 events); (2) failure of needles to retract and operator had to pull the device out of the skin (2 events); and (3) slow flow (1 event). Emergency department physicians noted two events of minor bleeding around the site of device placement.

Conclusion: This is the first study to prospectively evaluate the prehospital use of the FAST-1 sternal IO as a first-line device to obtain vascular access in the critically ill or injured patient. The FAST-1 sternal IO device can be a valuable tool in the paramedic arsenal for the treatment of the critically ill or injured patient. The device may be of particular interest to specialty disaster teams that deploy in austere environments.

Evaluation of success rate and access time for an adult sternal intraosseous device deployed in the prehospital setting
Prehosp Disaster Med 2011;26(2):127–129

CVCs placed in the ED

Central lines in the ED are more likely to get infected because they’re inserted under less scrupulously aseptic conditions than in ICU, done more urgently, and are more likely to be placed in the mucky old femoral site by clumsy emergency physicians who don’t wash their hands after scratching their arses. Anyway, the intensivists will usually replace them with a ‘more ideal’ line after ICU admission. Right? Well, that’s what’s often taught and assumed to be the case, but a new study from a single centre suggests otherwise. ED-placed central venous catheters (19% of which were femoral) were typically left in for 4 to 5 days. The infection rate was 1.9 per 1,000 catheter-days, similar to that reported for central lines in other ICU case series.

Infection and Natural History of Emergency Department–Placed Central Venous Catheters
Annals of Emergency Medicine 2010;56(5):492-7

Novel subclavian cannulation method

Ultrasound-guided subclavian vein cannulation has reduced complications, but there is still a high incidence of failure to cannulate the vein and of accidental arterial cannulation. Vassallo & Bennett noticed that a fast running intravenous infusion in the ipsilateral arm of a patient produced variable echogenicity (lighter echos) in the subclavian vein. They describe deliberately using this appearance to both identify the subclavian vein and differentiate it from the subclavian artery.

With the intravenous infusion running with frequent drips in the drip chamber, the ultrasound beam is placed in long axis to the subclavian vessels in the subclavicular position. The angle of the ultrasound beam is adjusted to reveal both the subclavian vein and artery. The variable echogenicity, together with compression, can then be used to identify the vein. The presence of variable echogenicity in the vessel gives continuous feedback that the ultrasound beam has not drifted onto the artery. In cases where the ultrasound beam has included both artery and vein in the same image, this method has clearly identified the intended target vessel.

Subclavian cannulation with ultrasound: a novel method
Anaesthesia, 2010;65:1041

Two smaller lines may be quicker

Using Poiseuille’s law and standardized gauge sizes, an 18-gauge (g) intravenous catheter (IV) should be 2.5 times faster than a 20-g IV, but this is not borne out by observation, in vitro testing, and manufacturer’s data. A nice simple study on normal volunteers compared simultaneous flow rates between a single 18G iv in one arm with two 20G ivs in the other arm. The two smaller ones provided significantly faster flow than the single larger one, although flow rates were slower than manufacturer’s estimates. This is in keeping with this other study on cannula flow rates.

Are 2 smaller intravenous catheters as good as 1 larger intravenous catheter?
Am J Emerg Med. 2010 Jul;28(6):724-7