Postoperative Screening With the Modified National Institutes of Health Stroke Scale After Noncardiac Surgery: A Pilot Study

Background: Perioperative stroke is associated with high rates of morbidity and mortality, yet there is no validated screening tool. The modified National Institutes of Health Stroke Scale (mNIHSS) is validated for use in nonsurgical strokes but is not well-studied in surgical patients. We evaluated perioperative changes in the mNIHSS score in noncardiac, non-neurological surgery patients, feasibility in the perioperative setting, and the relationship between baseline cognitive screening and change in mNIHSS score. Methods: Patients aged 65 years and above presenting for noncardiac, non-neurological surgery were prospectively recruited. Those with significant preoperative cognitive impairment (Montreal Cognitive Assessment score [MoCA] <= 17) were excluded. mNIHSS was assessed preoperatively, on postoperative day (POD) 0, POD 1, and POD 2, demographic data collected, and feedback solicited from participants. Changes in mNIHSS from baseline, time to completion, and relationship between baseline MoCA score and change in mNIHSS score were analyzed. Results: Twenty-five patients were enrolled into the study; no overt strokes occurred. Median mNIHSS score increased between baseline (0 interquartile range [IQR 0 to 1]) and POD 0 (2 [IQR 0 to 3.5]; P<0.001) but not between baseline and POD 1 (0.5 [IQR 0 to 1.5]; P=0.174) or POD 2 (0 [IQR 0 to 1]; P=0.650). Time to complete the mNIHSS at baseline was 3.5 minutes (SD 0.8), increasing to 4.1 minutes (SD 1.0) on POD 0 (P=0.0249). Baseline MoCA score was correlated with mNIHSS score change (P=0.038). Perioperative administration of the mNIHSS was feasible, and acceptable to patients. Conclusions: Changes in mNIHSS score can occur early after surgery in the absence of overt stroke. Assessment of mNIHSS appears feasible in the perioperative setting, although further research is required to define its role in detecting perioperative stroke.

Automated summary

This study aimed to evaluate the perioperative changes in mNIHSS score in noncardiac, non-neurological surgery patients, showing an increase in mNIHSS score on postoperative day 0 but not on postoperative day 1 or 2. The time to complete the mNIHSS assessment was extended postoperatively, and baseline MoCA score was correlated with mNIHSS score change.