Effect of aspirin in vascular surgery in patients from a randomized clinical trial (POISE-2).

BACKGROUND: In the POISE-2 (PeriOperative ISchemic Evaluation 2) trial, perioperative aspirin did not reduce cardiovascular events, but increased major bleeding. There remains uncertainty regarding the effect of perioperative aspirin in patients undergoing vascular surgery. The aim of this substudy was to determine whether there is a subgroup effect of initiating or continuing aspirin in patients undergoing vascular surgery. METHODS: POISE-2 was a blinded, randomized trial of patients having non-cardiac surgery. Patients were assigned to perioperative aspirin or placebo. The primary outcome was a composite of death or myocardial infarction at 30 days. Secondary outcomes included: vascular occlusive complications (a composite of amputation and peripheral arterial thrombosis) and major or life-threatening bleeding. RESULTS: Of 10 010 patients in POISE-2, 603 underwent vascular surgery, 319 in the continuation and 284 in the initiation stratum. Some 272 patients had vascular surgery for occlusive disease and 265 had aneurysm surgery. The primary outcome occurred in 13·7 per cent of patients having aneurysm repair allocated to aspirin and 9·0 per cent who had placebo (hazard ratio (HR) 1·48, 95 per cent c.i. 0·71 to 3·09). Among patients who had surgery for occlusive vascular disease, 15·8 per cent allocated to aspirin and 13·6 per cent on placebo had the primary outcome (HR 1·16, 0·62 to 2·17). There was no interaction with the primary outcome for type of surgery (P = 0·294) or aspirin stratum (P = 0·623). There was no interaction for vascular occlusive complications (P = 0·413) or bleeding (P = 0·900) for vascular compared with non-vascular surgery. CONCLUSION: This study suggests that the overall POISE-2 results apply to vascular surgery. Perioperative withdrawal of chronic aspirin therapy did not increase cardiovascular or vascular occlusive complications. Registration number: NCT01082874 ( http://www.clinicaltrials.gov).

Endovascular repair of popliteal artery aneurysms with Anaconda limbs: technique and early results.

OBJECTIVES: The objective is to report the feasibility and technique of treating popliteal artery aneurysms (PAA) with a stent made of nitinol rings externally supported by thin polyester (Anaconda limbs). BACKGROUND: PAA are the most common peripheral aneurysms. The main limitations of stents used in these settings are: short lengths, longitudinal and horizontal compliance mismatch; graft failure from angulation and movement at the joint level; and dislodgment. METHODS: This is a prospective multicenter cohort study of consecutive symptomatic and asymptomatic PAA treated in tertiary vascular centers. Outcomes included patency of the stent and postoperative time-to-independent-ambulation and to-climb-a-flight-of-stairs. RESULTS: Fourteen PAA were treated in 12 men, age 72 +/- 3 years. The median ASA classification was 2.5. The length of artery covered was 147 +/- 41 mm. The PAA diameter was 31 +/- 5 mm, 6 were symptomatic. One stent was used in 6 aneurysms, two in 7, and three in 1. The average stent diameter was 10 +/- 1 mm. The length of the proximal neck was 24 +/- 6 mm with a diameter of 9.8 +/- 1.9, and length of the distal neck 23 +/- 3 mm with a diameter of 8.7 +/- 1.2 mm. In 6 aneurysms, the stent crossed the knee joint. There was no mortality, and one stent occluded (primary patency 93% at 6 +/- 3 months). The median hospital stay was 1.7 days, time to independent ambulation was 3 hr and the time to climbing a flight of stairs was 1 day. CONCLUSIONS: The use of Anaconda limbs for endovascular repair of PAA is feasible and safe.

Is clinical examination an accurate indicator of raised intra-abdominal pressure in critically injured patients?

OBJECTIVES: To determine the rate of elevated intra-abdominal pressure (IAP) and to evaluate the accuracy of clinical abdominal examination in the assessment of IAP in the critically injured trauma patient. DESIGN: A prospective blinded study. SETTING: The medical-surgical critical care unit of a university-affiliated regional adult trauma centre. PATIENTS: Forty-two adult blunt trauma victims, who had a mean injury severity score of 36. INTERVENTIONS: Urinary bladder pressure was measured daily and classified as normal (10 mm Hg or less), elevated (more than 10 mm Hg) or significantly elevated (more than 15 mm Hg). A blinded clinical assessment of abdominal pressure was concurrently performed and recorded as elevated or normal. MAIN OUTCOME MEASURES: The sensitivity, specificity and accuracy and the positive and negative predictive values of the 2 interventions in identifying elevated IAP. RESULTS: Twenty-one patients (50%) had an elevated IAP at some point during the study. Of the 147 bladder pressure measurements done in these 42 patients, 47 (32%) were more than 10 mm Hg and 16 (11%) were more than 15 mm Hg. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of clinical abdominal examination for identifying elevated IAP were 40%, 94%, 76%, 77% and 77%, respectively. Clinical abdominal examination had a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 56%, 87%, 35%, 94% and 84% respectively, for significantly elevated IAP. CONCLUSIONS: Urinary bladder pressure was commonly elevated among our population of critically injured adults. Compared with bladder pressure measurements, clinical abdominal assessment showed poor sensitivity and accuracy for elevated IAP. These findings suggest that more routine measurements of bladder pressure in patients at risk for intra-abdominal hypertension should be performed.

Rectal indomethacin reduces postoperative pain and morphine use after cardiac surgery.

PURPOSE: To evaluate the combination of rectal indomethacin with patient controlled intravenous morphine analgesia (PCA) on postoperative pain relief and opioid use after cardiac surgery. METHODS: With institutional ethics approval, 57 consenting adults undergoing elective aortocoronary bypass surgery were randomly assigned preoperatively in a double-blind fashion to receive either placebo (n = 26) or indomethacin 100 mg suppositories (n = 31), 2-3 hr postoperatively, and 12 hr later. Both groups utilized PCA morphine. Pain scores in the two treatment groups were assessed on a 10-cm visual analogue scale (VAS) (at rest and with cough) at 4, 6, 12, 18 and 24 hr after initial dosing, and were analyzed through a 2 x 5 repeated measures of variance. The 24 hr analgesic consumption, 12 and 24 hr chest tube blood loss, and time to tracheal extubation were also recorded, and compared for the two treatment arms through Student's t test on independent samples. RESULTS: Postoperative morphine consumption in the first 24 hr was 38% less in the indomethacin group (22.40 +/- 12.55 mg) than the placebo group (35.99 +/- 25.84 mg), P = 0.019. Pain scores, measured with a VAS, were 26% to 66% lower in the indomethacin vs placebo group at rest (P = 0.006), but not with cough, for all times assessed. There was no difference in blood loss (at 12 hr) or time to tracheal extubation for both groups. CONCLUSION: The combination of indomethacin with morphine after cardiac surgery results in reduced postoperative pain scores and opioid use without an increase in side effects.

The anesthetic record: accuracy and completeness.

PURPOSE: To evaluate if anesthesia training and experience influenced chart completion and accuracy. METHODS: One hundred and twenty-four subjects, including medical students, anesthesia residents and community and university based clinical anesthesiologists, were given a standardized patient in a simulator environment and asked to conduct induction and maintenance of anaesthesia. Three critical events were introduced resulting in changes in BP, HR, PETCO2 and SpO2. Subjects were instructed to manage the patient and the anesthetic chart, as was their customary practice. Discrepancy, calculated as the difference between the actual and charted values divided by the actual physiological value was compared by level of training with a two-way repeated measures analysis of variance (ANOVA) for all four physiological variables. The completeness of charting, defined as at least one data point recorded for each of the four physiological variables of the three critical events, was compared across level of training, age of participants and number of years in practice. RESULTS: The overall completeness of charting remained low (< 37%) with no relationship based on the anesthesiologist's age, level of training or number of years in practice. There was discrepancy in charting for all physiological variables (HR, BP, PETCO2 and SpO2, P < 0.0001), with a marked difference in the degree of discrepancy within each level of training. Training resulted in no differences in charting discrepancy. CONCLUSION: Charting of data to the anesthetic record remained incomplete and inaccurate in all groups based on level of training, age and number of years in practice.

The ventilatory response to hypoxia below the carbon dioxide threshold.

The ventilatory response to acute progressive hypoxia below the carbon dioxide threshold using rebreathing was investigated. Nine subjects rebreathed after 5 min of hyperventilation to lower carbon dioxide stores. The rebreathing bag initially contained enough carbon dioxide to equilibrate alveolar and arterial partial pressures of carbon dioxide to the lowered mixed venous partial pressure (approximately equal to 30 mmHg), and enough oxygen to establish a chosen end-tidal partial pressure (50-70 mmHg), within one circulation time. During rebreathing, end-tidal partial pressure of carbon dioxide increased while end-tidal partial pressure of oxygen fell. Ventilation increased linearly with end-tidal carbon dioxide above a mean end-tidal partial pressure threshold of 39 +/- 2.7 mmHg. Below this peripheral-chemoreflex threshold, ventilation did not increase, despite a progressive fall in end-tidal oxygen partial pressure to a mean of 37 +/- 4.1 mmHg. In conclusion, hypoxia does not stimulate ventilation when carbon dioxide is below its peripheral-chemoreflex threshold.