Management of the flap patient

Managing oncology patients post-operatively will be one of the most important and challenging jobs you do. They require specific monitoring with regards to their flaps to detect early failure. Most major surgical complications will occur within the first 72 hours of the operation and in this time, the flap requires consistent and regular monitoring. Generally, flap failure is due to ischemia or congestion. Early detection of flap failure will enable potential salvage of the flap by return to theatre.

How to monitor free flaps

1) Temperature – A cold flap indicates poor blood supply, it should be warm
2) Capillary refill – Normal capillary refill is approximately 3 seconds. Deviations from this figure could indicate vascular compromise.
3) Texture – If the flap is swollen (turgid) and firm it may represent a congested flap resulting from poor venous supply. A "spongy" flap could be an indicator of poor arterial supply
4) Colour – A change in colour is usually one of the first signs to indicate there is an issue with the flap. The flap should be the same colour as the original tissue surrounding the donor site. A pale or blue flap is particularly concerning.
5) Doppler signal - The probe is placed near the site of anastomosis and an audible signal indicating blood flow should be observed (‘whooshing’ sound). This type of test will be done by your registrar/consultant. (Try to ensure you have a working Doppler for the ward round)
6) Pin-prick testing - The flap is scratched with a blue needle anf if bleeding is observed from this site it indicates a healthy flap. IMPORTANT: this test is only to be done by a consultant!
If you have any concerns about the flap, always escalate to your seniors. Flap failure is a major surgical complication and necessitates a return to theatre.

If you are on-call late or overnight, try to see the flap when the operation ends or in recovery. The flap should also be observed throughout the day. Ensure you note the colour of the flap as there are many occasions when others may call you to say that flap has become pale when in fact, the skin paddle was pale in the first place [1]. Regardless, if a colleague asks you to examine a free flap, notify your registrar.

Figure 1. Normal appearance of an ALT flap [2]

Figure 2. Venous stasis post-operatively [3]

Surgical drains

If you haven’t worked in OMFS before, a surgical drain may be new. It is essentially a tube placed in a surgical wound and is used to remove blood and fluids from a wound using a vacuum. They are inserted towards the end of the operation and are sutured to secure them. They are usually in-situ for 2-5 days post-operatively depending on how much they drain.
The drains themselves have markings in “ml” so that you are able to monitor how much blood/fluid has been draining since the operation. The volume of drainage is usually recorded by the nurses on a drain chart.
It is vital that when you are on-call you know the volume that has drained in the last 24hrs as this provides an indication of progress post-operatively. For example, if a patient is consistently draining 300ml every day for 4-5 days, you may suspect there is a bleed somewhere and this needs prompt investigation. This will also disturb the patient’s fluid balance.
To gain an accurate measurement of drainage, ensure you deflate the drain before reading the volume (ask someone to show you how to do this). However, the drain must be re-vacuumed.

Enteral feeding

Every oncology patient will require planning for feeding. Often after large resections and reconstructions patients lose the ability to protect their airway when swallowing representing an aspiration risk. In addition to this, the flap needs protection early on from oral intake. Therefore you must provide ways to feed these patients. There are a few ways to achieve this:
1) Nasogastric tube (NGT)
2) Percutaneous endoscopic gastrostomy (PEG)
3) Radiologically inserted gastrostomy (RIG)

Nasogastric tube (NGT)

These can be inserted pre-operatively and are used when the patient does not have a RIG/PEG. This is not a long term option and once we are confident the patient can safely swallow (often with input from the speech and language team and the dieticians) then it may be removed. Note it can also be used to deliver medications. It is passed via the nose into the oropharynx and upper GIT. Once inserted, it is always worth noting down the length at which it is inserted. This allows a baseline reading and therefore if it needs to be advanced/retracted by 5cm for example, this can be measured accurately. Note: average length for an adult is 55-65cm. If you have not placed an NG tube before, seek help from senior colleagues.
The position of the NGT MUST be confirmed before you start to use it. This can be done in 2 ways:
1) Obtain an aspirate from the NGT and check the pH (should be 0-5.5)
2) Chest radiograph if unable to obtain an aspirate. Note this may be common for patients taking PPIs. It is essential to ask either a medic or a radiologist to confirm the NGT is the in the correct position as there are various checks you need to do.

Figure 5. Correct position of an NGT on a chest x-ray [5]

RIG/PEG

When a long term solution for feeding is required, we will often use a RIG/PEG. It is essential a tube which connects your stomach to the overlying skin. As with an NG tube, it can be used for feeding and to administer medications.
On occasion, patients attend hospital prior to free flap surgery to have a RIG/PEG inserted. This is more comfortable for the patient post-operatively relative to an NGT and faciltates discharge. Whether a patient receives a RIG/PEG pre/post-operatively, before the procedure you must ensure:
1) You have an up to date clotting screen (ideally done on the morning of the procedure/night before)
2) Patent cannula
3) A bed on the ward – the patient will need to stay overnight for observations
After insertion the patient and site are monitored for a period of time (differs by trust, check local protocol). It can then be used for feeding and administering medications. It should be monitored on a daily basis to ensure there is no bleeding/displacement of the tube.
Note PEG/RIG sites constitute surgical sites therefore in the event of an infection; these sites should also be examined (see surgical site infections below).

Monitoring Hb levels

Careful monitoring of Hb is required as it can directly impact the perfusion and subsequently, the vitality of the flap. Most patients can lose up to 2 litres of blood intra-operatively (e.g. bony flaps) therefore pre-operative Hb levels should be checked and the patient transfused if necessary. As a general rule, on admission, all oncology patients should have an FBC, U&E, CRP, clotting screen and G&S (group and save). Ensure the paperwork is correct especially for G&S otherwise the sample will be rejected.
IMPORTANT: Ensure you know where the flap is going to harvested from as blood should never be taken from that limb.
It is important to establish what the threshold for transfusion is at your trust and you must not transfuse anyone without the permission of your consultant.
If the Hb drops below your established threshold you must do the following:
1) Let your registrar/senior know
2) Check if they have a valid G&S (they are valid for a set time period). If it is not valid, you will need to another sample.
3) Insert a cannula (must be pink or above) if the patient does not have one
4) Transfuse (the number of units to be transfused is governed by how low the Hb is and this is not a decision you should making yourself. Your registrar/consultant will give you this information). Note if the Hb is consistently dropping even after transfusions, this must be investigated and raised with your senior.

Infections

These patients are susceptible to infections for a number of reasons – immobility, pre-existing medical conditions, lack of protective reflexes (aspiration) to name a few. Your daily bloods and observations should provide a good indicator of an infection if present. WBC and CRP are the common markers we analyse. You must look at the trend for these markers, examining them in isolation will not provide useful information. If there is an increase in these markers day by day, this may represent an infection.
When an infection is suspected, it is recommended to perform a number of investigations:
1) FBC, U&Es, CRP
2) Chest examination and chest x-ray
3) Urine dipstick test
4) Examination of all surgical sites (remove dressings if required and wound swabs if necessary)
Subtle changes in patient's observations can represent infection and therefore these need to be monitored and documented daily.

Chest

In the event of an infection one of the first areas to examine is the chest. During anaesthesia and post-operatively when the patient is not mobilizing well, there is a decrease in the clearance of secretions. This accumulation can lead to obstruction and collapse of the peripheral airways referred to as atelectasis. If this is not resolved it may progress to pneumonia. If you suspect this you should do the following:
1) Liaise with your senior
2) Chest x-ray
3) Prescribe antibiotics (check trust protocol) and nebulisers if the patient is particularly ‘chesty’
4) Encourage mobilisation
5) Breathing exercises and regular chest physio
One way to help prevent this involves the use of saline nebulisers and humidified oxygen.
IMPORTANT: With all oxygen/nebuliser masks ensure the securing tapes are not placed around the neck as this could potentially compromise flap vitality. There are a number of alternatives for securing these masks e.g. securing to patient gown.

Urinary tract infections

Due to the length of the operations, these patients have urinary catheter inserted to collect urine when the patient is anaesthetized and also measure output.
We should aim to remove urinary catheters 2-3 days post-operatively as they are a foreign body and a source of infection. In addition to this, they compromise mobility.
If you suspect a UTI, a urine sample should be taken for dip stick testing and a sample sent to the lab for culture. If the results indicate a UTI, antibiotics should be prescribed in line with trust guidelines.

Surgical site infections (SSIs)

While they may be less common than a chest infection, it is essential to do a thorough examination when you suspect an infection.
Broadly they can be characterized into superficial (skin, subcutaneous tissue) and deep infections. In these situations, you should be examining the free flap, donor site and any areas where a skin graft was taken from.
If you notice a purulent discharge from any site, it is always recommended to swab the site and send to microbiology for MC&S.
It is also worth checking for signs of infection around cannula's, central lines or any other lines which may be in situ.
SSIs can be managed in a variety of ways however it is always best to seek guidance from seniors in these circumstances [8].

Figure 9. Non-healing donor site (RFFF) [10]

When to involve the registrar

1) If you or others suspect failure of the flap based on the monitoring criteria
2) Inflammatory markers indicating an infection
3) Significant Hb drops or below the stated threshold
4) Purulent discharge/signs of an infection from a surgical site
5) Deteriorating patient
6) Situations you are uncomfortable managing

References

[1] VASILESCU D, DIACONU C, DIACONU C, GHEORGHSEAN-GALATEANU A. Guidelines for post-operative care and monitoring of free flaps [Internet]. Umbalk.org. 2020 [cited 14 June 2020]. Available from: https://umbalk.org/guidelines-for-post-operative-care-and-monitoring-of-free-flaps/
[2] Numajiri T, Morita D, Tsujiko S, Nakamura H, Sowa Y, Arai A et al. Dual Vascular Free Anterolateral Thigh Flap. Plastic and Reconstructive Surgery - Global Open. 2017;5(8):e1448.
[3] Koerdt S, Rommel N, Rohleder N, Sandig S, Frohwitter G, Steiner T et al. Perioperative serum levels of procalcitonin, C-reactive protein, and leukocytes in head and neck free flaps. International Journal of Oral and Maxillofacial Surgery. 2017;46(6):699-705.
[4] About Your Neck Dissection Surgery [Internet]. Memorial Sloan Kettering Cancer Center. 2020. Available from: https://www.mskcc.org/cancer-care/patient-education/neck-dissection
[5] Nasogastric (NG) Tube Placement - Oxford Medical Education [Internet]. Oxford Medical Education. 2020. Available from: http://www.oxfordmedicaleducation.com/clinical-skills/procedures/nasogastric-ng-tube/
[6] Radiologically Inserted Gastrostomy [Internet]. London; 2019. Available from: https://www.stgeorges.nhs.uk/wp-content/uploads/2019/09/MAX_RIG_02_LP.pdf
[7] The Radiology Assistant : Chest X-Ray - Lung disease [Internet]. Radiologyassistant.nl. 2020 [cited 14 June 2020]. Available from: https://radiologyassistant.nl/chest/chest-x-ray-lung-disease
[8] Yao C, Ziai H, Tsang G, Copeland A, Brown D, Irish J et al. Surgical site infections following oral cavity cancer resection and reconstruction is a risk factor for plate exposure. Journal of Otolaryngology - Head & Neck Surgery. 2017;46(1).
[9] Healing Donor Site. Nottingham University Hospital, 2020.
[10] Non-healing Donor Site. Nottingham University Hospital, 2020.