A compressomyograph train of four monitoring device

The monitoring of the neuromuscular blockade is critical for patient's safety during and after surgery. The monitoring of neuromuscular blockade often requires the use of Train of Four (TOF) technique. During a TOF test two electrodes are attached to the ulnar nerve, and a series of four electric pulses are applied. The electrical stimulation causes the thumb to twitch, and the amount of twitch varies depending on the amount of neuromuscular blockade in patient's system. Current medical devices used to assist anesthesiologists to perform TOF monitoring often require free hand movement and do not provide accurate or reliable results. The goal of this work is to design, prototype and test a new medical device that provides reliable TOF results when thumb movement is restricted. A medical device that uses a pressurized catheter balloon to detect the response thumb twitch of the TOF test is created. An analytical model, numerical study, and mechanical finger testing were employed to create an optimum design. The design is tested through a pilot human subjects study. No significant correlation is reported with subjects' properties, including hand size.

Prevalence and Factors Associated with Burnout Syndrome in Colombian Anesthesiologists

BACKGROUND

Burnout is characterized by the presence of emotional exhaustion, depersonalization, and low personal accomplishment, and manifests itself in difficulties in the handling of the psychological aspects of personal relationships with patients, by taking a negative attitude toward them. The objective was to evaluate the associated factors and describe the prevalence of burnout in Colombian anesthesiologists.

METHODS

A cross-sectional observational study. The classification of burnout was carried out using two criteria: the first related to high emotional exhaustion, accompanied by either high depersonalization or low personal accomplishment; the second associated with high emotional exhaustion in conjunction with both high depersonalization and low personal accomplishment. The prevalence and the variables associated with the presence of Burnout were described according to each criterion.

RESULTS

19.2% of the respondents were categorized as having burnout according to the first criterion and 9.2% according to the second criterion. The results are consistent regardless of the criterion used to define burnout; the associated factors were the presence of depression, anxiety, the degree of satisfaction with the profession, more than 200 hours worked per month and being an at-risk drinker. Anxiety was found to be associated with increased risk of both criteria 1 and 2 burnout.

CONCLUSIONS

In line with other studies, the prevalence of burnout among Colombian anesthesiologists varies depending on the burnout criteria. However, a strong correlation was noted with depression, anxiety, low satisfaction with professional career and high number of working hours per month.

Clinical Significance of Standing versus Reversed Trendelenburg Position for the Diagnosis of Lower-Extremity Venous Reflux in the Great Saphenous Vein

Introduction

Sonographic detection of incompetence in the deep and superficial veins requires proper patient positioning. Although these tests have been traditionally performed in the reversed Trendelenburg (RT) position, recent mandates from The Intersocietal Commission for the Accreditation of Vascular Laboratories and some insurance providers require that patients be evaluated for reflux in the standing position (SP). The purpose of this study was to determine whether performing venous duplex in the SP versus RT position adds information that affects patient treatment.

Methods

Twenty-eight subjects (25 women; mean age of 52 years) with signs and symptoms of venous insufficiency were evaluated prospectively with the use of ultrasound imaging and Doppler in the 5- to 8-MHz ranges. The great saphenous vein (GSV) was evaluated for each limb from below the knee to the saphenofemoral junction. Patients were initially evaluated at 15–25 degrees of RT position. Reflux was defined by reversal of flow for >0.5 seconds via use of the Valsalva and/or manual compression maneuvers. The GSV was measured in A-P diameter at the saphenofemoral junction and at the knee level. The subjects were then elevated to SP and measurements were repeated while the limb was in a nonweight-bearing position.

Results

A total of 52 limbs were evaluated for venous reflux in 28 study subjects. The mean lower-extremity CEAP score was 3 SD ± 3. Twenty-six (50%) GSVs were positive for venous reflux in the RT position. Of these GSVs, three were negative for reflux in SP. Twenty-seven (53%) GSVs were positive for venous reflux in SP; however, four of these GSVs were negative for reflux in RT. The median difference in reflux time from RT to SP was 0.15 seconds (interquartile range 0–3.8 seconds and 0–2.7seconds, respectively, p = 0.02). The mean difference in GSV diameter from RT to SP was 0.7 mm (±0.96 mm SD, p < 0.0001). These results changed the clinical course for one subject who did not have reflux in RT but did in SP (3.5%, p = 0.085).

Conclusion

The results from evaluating subjects in SP were not independently associated with a change in clinical outcome. However, 15% of GSVs negative for reflux in RT were positive for reflux in the SP. As a result, 3.5% of subjects in our study had a change in clinical course as the result of evaluation of the GSV in SP. This finding suggests that failure to identify GSV reflux in RT in patients with signs and symptoms of venous insufficiency may be an indication to evaluate the GSV in SP.

Effects of fentanyl administration before induction of anesthesia and placement of the Laryngeal Mask Airway: a randomized, placebo-controlled trial

STUDY OBJECTIVE

To assess the effects of fentanyl administered before induction of anesthesia on movement and airway responses during desflurane anesthesia via the Laryngeal Mask Airway (LMA).

DESIGN

Randomized, double-blinded, controlled trial.

STUDY SETTING

Tertiary-care academic center.

PATIENTS

100 adult, ASA physical status 1, 2, and 3 patients undergoing ambulatory surgery.

INTERVENTIONS

Patients were administered fentanyl 1 μg/kg (n=51) or saline (n=49) 3 to 5 minutes before induction with propofol 2-2.5 mg/kg intravenously (IV), followed by LMA placement. Anesthesia was maintained with desflurane titrated to a bispectral index (BIS) of 50-60 and 50% nitrous oxide in oxygen, and fentanyl 25 μg boluses were titrated to respiratory rate.

MEASUREMENTS

Apnea occurrence and duration of manual ventilation, as well as frequency and severity of movement, coughing, breath holding, and laryngospasm were recorded.

MAIN RESULTS

Two patients in each group were excluded from analysis. The fentanyl pretreatment group had a higher frequency of apnea (94% vs 64%; P=0.0003) and longer duration of manual ventilation (3 [interquartile range (IQR), 1.5-5] min vs 1 [0-1.5] min; P<0.0001) at induction. In contrast, the fentanyl pretreatment group had a lower frequency of movements (16% vs 51%;P=0.0001). The rates of intraoperative breath holding (6.1% vs 8.5%) and laryngospasm (2% vs 4.3%) in the two groups were similar. All subjects experiencing laryngospasm were smokers. Adjusting for smoking status did not affect the differences noted in apnea, duration of manual ventilation, or movement between groups; however, coughing occurrence was statistically higher in the placebo group (P=0.043).

CONCLUSIONS

Preinduction fentanyl increased the frequency of apnea at induction and duration of manual ventilation, but reduced the frequency of movements. In addition, it reduced intraoperative coughing in smokers.

Abdominal aortic atherosclerosis at MR imaging is associated with cardiovascular events: the Dallas heart study

PURPOSE

To determine the value of two abdominal aortic atherosclerosis measurements at magnetic resonance (MR) imaging for predicting future cardiovascular events.

MATERIALS AND METHODS

This study was approved by the institutional review board and complied with HIPAA regulations. The study consisted of 2122 participants from the multiethnic, population-based Dallas Heart Study who underwent abdominal aortic MR imaging at 1.5 T. Aortic atherosclerosis was measured by quantifying mean aortic wall thickness (MAWT) and aortic plaque burden. Participants were monitored for cardiovascular death, nonfatal cardiac events, and nonfatal extracardiac vascular events over a mean period of 7.8 years ± 1.5 (standard deviation [SD]). Cox proportional hazards regression was used to assess independent associations of aortic atherosclerosis and cardiovascular events.

RESULTS

Increasing MAWT was positively associated with male sex (odds ratio, 3.66; P < .0001), current smoking (odds ratio, 2.53; P < .0001), 10-year increase in age (odds ratio, 2.24; P < .0001), and hypertension (odds ratio, 1.66; P = .0001). A total of 143 participants (6.7%) experienced a cardiovascular event. MAWT conferred an increased risk for composite events (hazard ratio, 1.28 per 1 SD; P = .001). Aortic plaque was not associated with increased risk for composite events. Increasing MAWT and aortic plaque burden both conferred an increased risk for nonfatal extracardiac events (hazard ratio of 1.52 per 1 SD [P < .001] and hazard ratio of 1.46 per 1 SD [P = .03], respectively).

CONCLUSION

MR imaging measures of aortic atherosclerosis are predictive of future adverse cardiovascular events.

Intraoperative fluid restriction predicts improved outcomes in major vascular surgery

BACKGROUND

Traditional fluid resuscitation during general anesthesia has been questioned in recent studies. One study of patients undergoing abdominal surgery showed decreased postoperative weight gain, earlier return of bowel function, and shorter intensive care unit (ICU) and hospital length of stay (LOS) when intraoperative crystalloid infusion was restricted. The authors conducted a retrospective study of major vascular surgery patients (neo-aorto iliac system surgery) to correlate clinical outcomes with intraoperative crystalloid fluid administration.

METHODS

The charts of 41 patients who underwent major vascular surgery at our institution were reviewed. Patients were grouped according to the crystalloid volume infused intraoperatively into <3 L (group 1) and >3 L (group 2). Preoperative and postoperative weights, intraoperative crystalloid administration, intraoperative vasopressor use, preoperative and postoperative creatinine, number of days to clear liquid diet, and the time to discharge from the ICU (ICU LOS) and hospital (hospital LOS) were collected.

RESULTS

There were statistically significant differences in duration of mechanical ventilation (0.55 +/- 0.934 vs 2.03 +/- 2.735 days, P = .013) and ICU LOS (3.0 +/- 1.48 vs 5.79 +/- 3.938, P = .029) in favor of the fluid restriction group. Major postoperative complications, such as sepsis, acute myocardial infarction, and graft thrombosis, were less frequent in the fluid restriction group but not statistically significant (5 vs 9, P = .742). Intraoperative crystalloid volume was found to be an independent predictor of ICU LOS after adjusting for estimated blood loss and duration of surgery. There was no statistically significant difference in preoperative serum albumin in both groups.

CONCLUSIONS

Restricted intraoperative administration of crystalloid fluids (<3 L) may be beneficial in major vascular surgery patients. These benefits are similar to those previously described in patients undergoing abdominal surgery.