Automatic performance evaluation of the intracorporeal suture exercise

PURPOSE

This work uses deep learning algorithms to provide automated feedback on the suture with intracorporeal knot exercise in the fundamentals of laparoscopic surgery simulator. Different metrics were designed to provide informative feedback to the user on how to complete the task more efficiently. The automation of the feedback will allow students to practice at any time without the supervision of experts.

METHODS

Five residents and five senior surgeons participated in the study. Object detection, image classification, and semantic segmentation deep learning algorithms were used to collect statistics on the practitioner's performance. Three task-specific metrics were defined. The metrics refer to the way the practitioner holds the needle before the insertion to the Penrose drain, and the amount of movement of the Penrose drain during the needle's insertion.

RESULTS

Good agreement between the human labeling and the different algorithms' performance and metric values was achieved. The difference between the scores of the senior surgeons and the surgical residents was statistically significant for one of the metrics.

CONCLUSION

We developed a system that provides performance metrics of the intracorporeal suture exercise. These metrics can help surgical residents practice independently and receive informative feedback on how they entered the needle into the Penrose.

Two-year experience with rate-modulated pacing controlled by mixed venous oxygen saturation

Mixed venous oxy-hemoglobin saturation (MVO2) is a physiological variable with several features that might be desirable as a control parameter for rate adaptive pacing. Despite these desirable characteristics, the long-term reliability of the MVO2 sensor in vivo is uncertain. We, therefore, designed a study to prospectively evaluate the long-term performance of a permanently implanted MVO2 saturation sensor in patients requiring VVIR pacing. Under an FDA approved feasibility study, eight patients were implanted with a VVIR pulse generator and a right ventricular pacing lead incorporating an MVO2 sensor. In order to accurately assess long-term stability of the sensor, patients underwent submaximal treadmill exercise using the Chronotropic Assessment Exercise Protocol (CAEP) at 2 weeks, 6 weeks, and 3, 6, 9, 12, 18, and 24 months following pacemaker implantation. Paired maximal exercise testing using the CAEP was also performed with the pacing system programmed to the VVI and VVIR modes in randomized sequence with measurement of expired gas exchange after 6 weeks and 12 months of follow-up. During maximal treadmill exercise the peak exercise heart rate (132 +/- 9 vs 71.5 +/- 5 beats/min, P < 0.00001) and maximal rate of oxygen consumption (1,704 +/- 633 vs 1382 +/- 407 mL/min, P = 0.01) were significantly greater in the VVIR than in the VVI pacing mode. Similarly, the duration of exercise was greater in the VVIR than the VVI pacing mode (8.9 +/- 3.6 min vs 7.6 +/- 3.7 min, P = 0.04). The resting MVO2 and the MVO2 at peak exercise were similar in the VVI and VVIR pacing modes (P = NS). However, the MVO2 at each comparable treadmill exercise stage was significantly higher in the VVIR mode than in the VVI mode (CAEP stage 1 (P = 0.005), stage 2 (P = 0.04), stage 3 (P = 0.008), and stage 4 (P = 0.04). The correlation between MVO2 and oxygen consumption (VO2) was excellent (r = -0.93). Telemetry of the reflectance of red and infrared light and MVO2 in the right ventricle during identical exercise workloads revealed no significant change over the first 12 months of follow-up (ANOVA, P = NS). The chronotropic response to exercise remained proportional to VO2 in all patients over the first 12 months of follow-up. The time course of change in MVO2 during maximal exercise was significantly faster than for VO2. At the 18- and 24-month follow-up exercise tests, a significant deterioration of the sensor signal with attenuation of chronotropic response was noted for 4 of the 8 subjects with replacement of the pacing system required in one patient because of lack of appropriate rate modulation. Rate modulated VVIR pacing controlled by right ventricular MVO2 provides a chronotropic response that is highly correlated with VO2. This parameter responds rapidly to changes in workload with kinetics that are more rapid than those of VO2. Appropriate rate modulation provides a higher MVO2 at identical workloads than does VVI pacing. Although the MVO2 sensor remains stable and accurate over the first year following implantation, significant deterioration of the signal occurs by 18-24 months in many patients.

Azathioprine-induced multisystem organ failure and cardiogenic shock

Azathioprine is administered to treat increasing numbers of disorders over a wide range of organ systems. The potential for the drug to cause widespread organ dysfunction is not fully appreciated. In fact, azathioprine can cause multisystem organ dysfunction involving the kidneys, liver, and cardiovascular system. The discovery of global cardiac dysfunction as one component of this complication may indicate a mechanism of hypotension. Clinicians must be aware of the potential for azathioprine to cause such toxicities to facilitate appropriate patient management.

Diurnal and short-term variation of blood pressure: comparison of preeclamptic, chronic hypertensive, and normotensive patients

It has been suggested that the decrease in blood pressure during sleep is greater in patients with chronic hypertension than in preeclamptic patients. The DINAMAP (device for indirect noninvasive automatic mean arterial pressure) monitor was used to determine the mean arterial, systolic, and diastolic blood pressure, at 15-minute intervals, and 24 hours. Three groups of 15 patients each were studied: mildly preeclamptic, chronically hypertensive, and normotensive patients in the third trimester. In addition, 2 patients with severe preeclampsia were studied. The automatic readings were compared with auscultated blood pressures. There was short-term variation in the systolic and diastolic blood pressure of 20 to 40 and 15 to 30 mmHg, respectively, with consecutive 15-minute recordings. A decrease in blood pressure during sleep was seen in all groups, except in the 2 patients with severe preeclampsia. This fall varied between 5 and 20 mmHg systolic and 5 and 18 mmHg diastolic. The auscultated blood pressure differed from the automatic blood pressure by 5 to 40 mmHg systolic and 5 to 35 mmHg diastolic. In the clinical management of patients, these findings are significant, as they demonstrate short-term variation in blood pressure and differences in the auscultated versus automatic blood pressure readings. Also, changes in blood pressure occur during sleep; this may be important with regard to the timing and dose of medication given to pregnant patients with chronic hypertension or preeclampsia.