поработайте кулачком ( 1 фото )

Такую просьбу мы часто слышим от прекрасныхмедсестер, делающих венепункцию. К сожалению, как оказалось, при заборе крови для некоторых анализов такая практика можкт исказить их результат. Спорной является рекомендация, просто сжимания кулака (без "качания"), некоторые руководства против и этой облегчающей сам забор меры, но многие счмтают её допустимой.

Fist clenching should not be employed as an aid to venipuncture. It has been known since 1951(1), and has been repeatedly confirmed(2-5), that this will cause factitious elevation of plasma potassium. The phenomenon, which results from potassium entering venous effluent from the exercising forearm muscles(1,6), occurs at all levels of plasma potassium, which can then rise by as much as 1.5 mMol/l.

Consequences have included both the concealment of clinically significant hypokalaemia(4) and the appearance of seemingly pathological, but spurious, hyperkalaemia(5). Studies attempting to assess any effects of thiazides in lowering plasma potassium will have produced distorted results, tending to minimize such change, albeit to an extent which must remain speculative(7). In 1999 Gennari offered the reassurance that this is not an issue in the USA, since “ venipuncture specialists instruct patients not to clench their fists during blood sampling”(8). However, that assertion seems overly complacent. A recent article in the BMJ endorsed such fist clenching(9).

Moreover, the WHO guidelines on phlebotomy ( self-styled erroneously as “ best practices”) recommend the manoeuvre, even providing an illustration thereof(10). It is crucial that fist clenching is avoided at routine venipuncture. If however it is necessary the tourniquet should be released and the arm relaxed for 1-2 minutes before blood is drawn(2).

• 1. Farber SJ, Pellegrino ED, Conan NJ, Earle DP. Observations on the plasma potassium level of man. Am.J.Med.Sci, 1951; 221: 678-686.
• 2. Hultman E, Bergstrom J. Plasma potassium determination. Scand. J. Clin. Lab. Invest. 1962;14(Suppl.64): 87-93.
• 3. Skinner SL. A cause of erroneous potassium levels. Lancet 1961; 1: 478-480.
• 4. Brown JJ, Chinn RH, Davies DL, Fraser R, Lever AF, Rae RJ, Robertson JIS. Falsely high plasma potassium values in patients with hyperaldosteronism. BMJ 1970; 2: 18-20.
• 5. Don BR, Sebastian A, Cheitlin M, Christiansen M, Schambelan M. Pseudohyperkalemia caused by fist clenching at phlebotomy. New Engl. J. Med. 1990; 322: 1290-1292.
• 6. Fenn WO. Electrolytes in muscle. Physiol. Rev. 1936; 16: 450-487.
• 7. Singh BN, Hollenberg NK, Poole-Wilson PA, Robertson JIS. Diuretic-induced potassium and magnesium deficiency. J. Hypertens. 1992;10: 301-316.
• 8. Gennari FJ. Treatment of hypokalemia. New Engl. J. Med. 1999; 340: 155.
• 9. Dorrinton KL, Aronson JK. Failed phlebotomy? Think William Harvey. BMJ 2014; 349: g5232.
• 10. WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy. World Health Organization, Geneva, 2010.

BMJ 2014;349:g5232

Крепкого здоровья!