Decreases in daily ambulation forecast post-surgical re-admission.

BACKGROUND: Surgical readmissions are clinically and financially problematic. Our purpose is to determine if a decrease in postoperative ambulation (steps/day) is associated with hospital readmission. METHODS: In this prospective cohort study, patients undergoing elective operations wore an accelerometer activity tracker to measure steps/day for 28 consecutive postoperative days. The primary outcome was hospital readmission. The change in steps/day over two consecutive days prior to the day of the readmission were examined. Predetermined thresholds for decreases of consecutive daily ambulation levels were used to calculate sensitivity and specificity for the outcome of hospital readmission. RESULTS: 215 patients (aged 63 ± 12 years) were included. Readmission occurred in 10% (n = 21). For each of the first 28-postoperative days, the entire cohort had an average daily step increase of 136 ± 146 steps/day (Spearman correlation rho = 0.990; p < 0.001). A decrease in steps for two consecutive days of >50% from the prior day had a 79% sensitivity and 90% specificity for hospital readmission. CONCLUSIONS: A decrease of >50% daily ambulation (steps/day) over two consecutive post-discharge days accurately forecasts hospital readmission. The implications of these findings are that monitoring daily ambulation could serve as a form of outpatient telemetry aiding to forecast post-surgical readmissions.

Early identification of patients at risk for delayed recovery of ambulation after elective abdominal surgery.

BACKGROUND: Recovery of preoperative ambulation levels 1 month after surgery represents an important patient-centered outcome. The objective of this study is to identify clinical factors associated with the inability to regain baseline preoperative ambulation levels 28 days postoperatively. METHODS: This is a prospective cohort study enrolling patients scheduled for elective inpatient abdominal operations. Daily ambulation (steps/day) was measured with a wristband accelerometer. Preoperative steps were recorded for at least 3 full calendar days before surgery. Postoperatively, daily steps were recorded for at least 28 days. The primary outcome was delayed recovery of ambulation, defined as inability to achieve 50% of preoperative baseline steps at 28 days postoperatively. RESULTS: A total of 108 patients were included. Delayed recovery (< 50% of baseline preoperative steps/day) occurred in 32 (30%) patients. Clinical factors associated with delayed recovery after multivariable logistic regression included longer operative time (OR 1.37, 95% CI 1.05-1.79), open operative approach (OR 4.87, 95% CI 1.64-14.48) and percent recovery on POD3 (OR 0.73, 95% CI 0.56-0.96). In addition, patients with delayed ambulation recovery had increased rates of postoperative complications (16% vs 1%, p < 0.01) and readmission (28% vs 5%, p < 0.01). CONCLUSION: After elective inpatient abdominal operations, nearly one in three patients do not recover 50% of their baseline preoperative steps 28 days postoperatively. Factors that can be used to identify these patients include longer operations, open operations and low ambulation levels on postoperative day #3. These data can be used to target rehabilitation efforts aimed at patients at greatest risk for poor ambulatory recovery.

Postoperative delirium is associated with decreased recovery of ambulation one-month after surgery.

BACKGROUND: We hypothesized that postoperative delirium is associated with diminished recovery toward baseline preoperative ambulation levels one-month postoperatively. METHODS: Patients included were ≥60 years old undergoing inpatient operations. Ambulation was measured as steps/day using an accelerometer worn for ≥3-days preoperatively and ≥28-days postoperatively. Primary outcome was the percent recovery of preoperative steps. RESULTS: 109 patients were included; 17 (16%) developed postoperative delirium. Recovery of ambulation toward preoperative baseline at postoperative day-28 was decreased in delirium group (34% vs. 69%; p < 0.01). Immediate postoperative ambulation was similar in the delirium vs. no-delirium groups (p = 0.79). Delirium occurred on average on postoperative 3 ± 4 days. Subsequently, ambulation was decreased in the delirium group compared to non-delirium group at postoperative week-1 (p = 0.01), week-2 (p = 0.02), week-3 (p < 0.01) and week-4 (p < 0.01). CONCLUSION: Patients undergoing inpatient operations who develop delirium recover only one-third of their baseline steps one-month postoperatively. Postoperative delirium results in a decreased recovery towards baseline ambulation for at least 4-weeks following major operations in comparison to non-delirious patients. The decrease in ambulation in the delirium versus no-delirium groups occurred after the occurrence of postoperative delirium.

Wearable Technology-A Pilot Study to Define "Normal" Postoperative Recovery Trajectories.

BACKGROUND: Emerging wearable technology has the potential to quantify both preoperative and postoperative patient activity. The purpose of this study was to characterize postoperative recovery trajectories for 1 mo after common surgical procedures. MATERIALS AND METHODS: Patients included were scheduled for common elective operations. A wearable activity device was worn for at least 3 d preoperatively and 28 d postoperatively. Postoperative steps per day were compared with preoperative baseline steps, with recovery trajectories reported as a percentage of patients' baseline values. Recovery trajectories were compared between groups based on admission type and operation type. RESULTS: Two hundred ten patients were enrolled, and 143 patients (68%) completed follow-up. Patients took a median 5342 steps per day preoperatively and had significantly decreased steps on the first postoperative day, including those undergoing inguinal hernia repair (22% of baseline steps, P < 0.001). Four weeks postoperatively, steps per day had not returned to baseline in patients undergoing minimally invasive abdominal (88% of baseline, P = 0.035), open abdominal (64% of baseline, P = 0.002), and thoracic (32% of baseline, P = 0.002) operations. All groups of patients showed a rapid recovery of steps during the first postoperative week, followed by a slower return to baseline. Recovery trajectories differed based on both admission type and operation type. CONCLUSIONS: Wearable activity monitors provide useful technology for quantification of postoperative activity recovery trajectories of steps per day in comparison to preoperative activity levels, with internal validity differentiating recovery trajectories grouping by broad categorization of operation type and by admission type. Activity recovery is a patient-centered outcome that can be used for counseling as well as for intervening to improve activity levels after surgery.

Expression, Purification, and Biochemical Characterization of Human Afamin.

Afamin is an 87 kDa glycoprotein with five predicted N-glycosylation sites. Afamin's glycan abundance contributes to conformational and chemical inhomogeneity presenting great challenges for molecular structure determination. For the purpose of studying the structure of afamin, various forms of recombinantly expressed human afamin (rhAFM) with different glycosylation patterns were thus created. Wild-type rhAFM and various hypoglycosylated forms were expressed in CHO, CHO-Lec1, and HEK293T cells. Fully nonglycosylated rhAFM was obtained by transfection of point-mutated cDNA to delete all N-glycosylation sites of afamin. Wild-type and hypo/nonglycosylated rhAFM were purified from cell culture supernatants by immobilized metal ion affinity and size exclusion chromatography. Glycan analysis of purified proteins demonstrated differences in micro- and macro-heterogeneity of glycosylation enabling the comparison between hypoglycosylated, wild-type rhAFM, and native plasma afamin. Because antibody fragments can work as artificial chaperones by stabilizing the structure of proteins and consequently enhance the chance for successful crystallization, we incubated a Fab fragment of the monoclonal anti-afamin antibody N14 with human afamin and obtained a stoichiometric complex. Subsequent results showed sufficient expression of various partially or nonglycosylated forms of rhAFM in HEK293T and CHO cells and revealed that glycosylation is not necessary for expression and secretion.