Several methods have been developed for identifying and quantifying microcirculatory dysfunction in septic shock. We can measure buccal, sublingual and subcutaneous microcirculatory CO2-levels. Near infrared spectroscopy (NIRS) measures microcirculatory hemoglobin saturation. Sidestream dark field (SDF) imaging directly visualises the microcirculation. None of those, or the other existing modalities, are readily available at my hospital and most definitely not in the rural or prehospital settings where I sometimes start resuscitating septic patients. Fortunately, there is a ‘poor man’s version’ of all that technology. The mottling score.
A French group, Ait-Oufella et al, has published two papers focusing on a classical sign of septic circulatory shock, skin mottling. Skin mottling is the patchy skin discolouration we see in poorly perfused patients and is thought to represent poor microcirculation. Based on the observation that it is most commonly seen on the patient’s knees the authors designed a score based on the extent of mottling. Basically, the sicker the patient, the larger the extent of the mottling area.
0 – No mottling
1 – Coin sized mottling area on the knee.
2 – To the superior area of the knee cap.
3 – Mottling up to the middle thigh
4 – Mottling up to the fold of the groin
5 – Severe mottling that extends beyond the the groin.
The Mottling Score and survival in septic shock
The group published their first paper in 2011. The authors tried to find an association between septic shock outcomes and their Mottling Score. The first study included 60 septic shock patients from from a 7 month period.
The authors found that at 6 hours after admission arterial lactate levels, urinary output as well as mottling score were predictive of 14-day mortality. Of these, mottling score was the strongest predictor.
Interestingly, MAP, CVP, HR and cardiac index at 6 hours were not significantly associated with 14-day mortality. Changes in mottling score was also associated with resuscitation progress and changes in lactate levels and urinary output.
That first paper lives here:
Intensive Care Med. 2011 May;37(5):801-7. doi: 10.1007/s00134-011-2163-y. Epub 2011 Mar 4. Mottling score predicts survival in septic shock. Ait-Oufella H1, Lemoinne S, Boelle PY, Galbois A, Baudel JL, Lemant J, Joffre J, Margetis D, Guidet B, Maury E, Offenstadt G.
The authors also, fairly recently, published a paper demonstrating how the mottling score actually reflects skin hypoperfusion. Using a laser doppler they demonstrated how changes in mottling score reflected changes in skin perfusion in septic shock.
That one lives here:
Ann Intensive Care. 2013 Sep 16;3(1):31. doi: 10.1186/2110-5820-3-31. Alteration of skin perfusion in mottling area during septic shock. Ait-Oufella H1, Bourcier S, Alves M, Galbois A, Baudel JL, Margetis D, Bige N, Offenstadt G, Maury E, Guidet B.
Take home message
Interesting. Could work as a simple low-fi method for assessing and quantifying microcirculation in septic shock.