Flying After Surgery

A patient enquires about flying after surgery. What advice should be given?

Discussion

Some medical considerations regarding flying after surgery include:-

The effect of cabin pressure (“cabin altitude”). (Commercial aircraft normally decompress to approx. 75kPa or equivalent of 8000feet (2400m). (Some newer planes such as Dreamliners are designed to have a lower ‘cabin altitude’.)
The likelihood of postoperative (or other) in-flight complications or emergencies in an austere environment with limited medical facilities.
Patient comfort
Thromboembolic risk, particularly after surgery.
The duration and destination of the flight. Duration includes airport time.

Implications of the above include:

Inspired oxygen will be lower, and this may be a consideration in patients with respiratory compromise (e.g. postoperative atelectasis).
Gas-filled spaces will expand by approx. 33%. This may be critical after intraocular, intracranial, middle ear or sinus surgery. Pneumothoraces may expand (although hopefully these will have been identified). Expansion of bowel gas or pneumoperitoneum may be an issue to consider.
Patient should be comfortable with oral analgesics.
Motion-sickness may need prophylaxis

Pragmatically, the airline’s regulations (and interpretation of these by the staff) may be the major issue to deal with.

Qantas have a very detailed medical/travel guide (6 page document), including after surgery. It separates patients into those allowed to fly, and those requiring a medical clearance.
In the Qantas guide, otherwise healthy patients can fly 24 hours after anaesthesia.

The NHS NICE guideline is more succinct. Comments on nature of the surgery/ types of surgery.
Overall, the airline regulations about flying postoperatively do not appear to be unreasonably risk-averse.

DVT risk

It is surprising how little detailed advice is given with regard to DVT prophylaxis.
It is even more surprising how little really clear data there is about the risk – it remains an area of controversy. (There is a geographical bias in this: Most of the world regards four hours as a long flight.)
The incidence of DVT in long-haul passengers has been variously estimated at ‘10% in very long flights’; ‘up to 2%’ or symptomatic DVT in 1/4500 flights (Which still seems extraordinarily high!). Guidelines and recommendations vary in evidence and veracity.
Airlines advise plenty of fluids, exercise and walking around etc. but not TED stockings or even aspirin.
Self-administered Clexane (or any other hypodermic medication) may be problematic with security regulations. (Diabetics are advised to have clear documentation of their status.)

Other fun facts

The medical kit carried on planes is not standardised and even on long-haul flights varies between airlines.
Airlines have a limited supply of oxygen with very limited flow rates (2 or 4L/min) they are green cylinders as the colour for oxygen in America is green.
Local story: – Responded to patient collapsed on a 2018 flight ex-Dallas one hour out from Sydney. Massive pulmonary embolism: – The Qantas kit was very well organised, easy to follow etc. A defibrillator was available but not a 12-lead ECG, and no pulse oximeter!!!
Flying after Scuba-diving: – PADDI has detailed decompression tables, and the general rule is that flying is acceptable on ‘the day after a dive’ (but not in the case of decompression sickness). Note that PADDI tables are designed for decompression to sea-level. If diving at altitude, the decompression schedule needs to be adjusted to compensate for the lower pressure at the lake surface. Fresh water allows faster decompression. Modern dive computers detect changes in altitude and automatically adjust calculations for safe decompression. But even with the help of a computer, it may be worth bearing this in mind next time you are planning a scuba-dive at Lake Titicaca in Peru and Bolivia, at an altitude of 3,812m, with a mean depth of 135m. The atmospheric pressure at the surface is approx. 0.636Atm. (You will presumably be visiting the drowned pre-Incan temple discovered in 1999 at a depth of 30m.)

References

UK NHS/NICE Guidance to Public (from their website)
Qantas Medical advisory information
Firkin F, Nandurkar H, Flying and thromboembolism (Aust Prescr 2009;32:148–50)
Bartholomew J, Evans N; Travel-related venous thromboembolism Vascular Medicine. 2019(Feb);24(1):93–95 DOI: 10.1177/1358863X18818323
Daniels N; Severe deep venous thromboembolism presenting with syncope associated with airplane travel: A public health quandary American Journal of Emergency Medicine. 2018(Sept);36(9):1701–1702, DOI: 10.1016/j.ajem.2018.01.061
Nable JV, Tupe CL, Gehle BD, Brady WJ. In-Flight Medical Emergencies during Commercial Travel N Engl J Med 2015;373:939-45. DOI: 10.1056/NEJMra1409213
Martin-Gill C, Doyle TJ, Yealy DM In-Flight Medical Emergencies. A Review JAMA. 2018;320(24):2580-2590. doi:10.1001/jama.2018.19842

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