The effect of epidural blockade on postoperative hypercoagulability following abdominal aortic bypass surgery

Thromboelastography in elective total hip arthroplasty

BACKGROUND

Hypercoagulability plays an important role in predisposing patients to venous thromboembolism (VTE) after total hip arthroplasty (THA). We used thromboelastography (TEG) to examine the coagulation status of patients undergoing THA.

AIM

To examine coagulation as measured by TEG in patients undergoing THA who received standard VTE chemoprophylaxis with enoxaparin.

METHODS

After ethical approval, we performed a retrospective analysis of data collected in patients undergoing primary elective THA. We analyzed TEG data on samples performed before skin incision, intraoperatively and for 5 d postoperatively. Conventional coagulation tests were performed preoperatively and on postoperative day 5.

RESULTS

Twenty patients undergoing general anesthesia and 32 patients undergoing spinal anesthesia (SA) were included. TEG demonstrated a progressively hypercoagulable state postoperatively, characterized by elevated maximum amplitude. TEG also demonstrated transient intraoperative hypercoagulability in patients receiving SA. In contrast, conventional coagulation tests were normal in all patients, pre- and postoperatively, except for an increase in plasma fibrinogen day 5 postoperatively.

CONCLUSION

Despite VTE prophylaxis, patients following total hip replacement remain in a hypercoagulable state as measured by both TEG and conventional tests. This group may benefit from more optimal anticoagulation and/or additional perioperative hemostatic monitoring, via TEG or otherwise.

Epidural pain relief versus systemic opioid-based pain relief for abdominal aortic surgery

BACKGROUND

Epidural analgesia offers greater pain relief compared to systemic opioid-based medications, but its effect on morbidity and mortality is unclear. This review was originally published in 2006 and was updated in 2012 and again in 2016.

OBJECTIVES

To assess the benefits and harms of postoperative epidural analgesia in comparison with postoperative systemic opioid-based analgesia for adults undergoing elective abdominal aortic surgery.

SEARCH METHODS

In the updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and five trial registers in November 2014, together with reference checking to identify additional studies.

SELECTION CRITERIA

We included all randomized controlled trials comparing postoperative epidural analgesia and postoperative systemic opioid-based analgesia for adults who underwent elective open abdominal aortic surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information and data when required. We assessed the level of evidence according to the scale provided by the GRADE working group.

MAIN RESULTS

We included 15 trials published from 1987 to 2009 with 1498 participants in this updated review. Participants had a mean age between 60.5 and 71.3 years. The percentage of women in the included studies varied from 0% to 28.1%. Adding an epidural to general anaesthesia for people undergoing abdominal aortic repair reduced myocardial infarction (risk ratio (RR) 0.54 (95% confidence interval (CI) 0.30 to 0.97); I(2) statistic = 0%; number needed to treat for one additional beneficial outcome (NNTB) 28 (95% CI 19 to 1423), visual or verbal analogical scale (VAS) scores up to three days after the surgery (mean difference (MD) -1.78 (95% CI -2.32 to -1.25); I(2) statistic = 0% for VAS scores on movement at postoperative day one), time to tracheal extubation (standardized mean difference (SMD) -0.42 (95% CI -0.70 to -0.15); I(2) statistic = 83%; equivalent to a mean reduction of 36 hours), postoperative respiratory failure (RR 0.69 (95% CI 0.56 to 0.85); I(2) statistic = 0%; NNTB 8 (95% CI 6 to 16)), gastrointestinal bleeding (OR 0.20 (95% CI 0.06 to 0.65); I(2) statistic = 0%; NNTB 32 (95% CI 27 to 74)) and time spent in the intensive care unit (SMD -0.23 (95% CI -0.41 to -0.06); I(2) statistic = 0%; equivalent to a mean reduction of six hours). We did not demonstrate a reduction in the mortality rate up to 30 days (RR 1.06 (95% CI 0.60 to 1.86); I(2) statistic = 0%). The level of evidence was low for mortality and time before tracheal extubation; moderate for myocardial infarction, respiratory failure and intensive care unit length of stay; and high for gastrointestinal bleeding and VAS scores.

AUTHORS' CONCLUSIONS

Epidural analgesia provided better pain management, reduced myocardial infarction, time to tracheal extubation, postoperative respiratory failure, gastrointestinal bleeding, and intensive care unit length of stay compared with systemic opioid-based drugs. For mortality, we did not find a difference at 30 days.

Epidural pain relief versus systemic opioid-based pain relief for abdominal aortic surgery

BACKGROUND

Epidural analgesia offers greater pain relief compared to systemic opioid-based medications, but its effect on morbidity and mortality is unclear. This review was originally published in 2006 and was updated in 2011.

OBJECTIVES

To assess the benefits and harms of postoperative epidural analgesia in comparison with postoperative systemic opioid-based pain relief for adult patients who underwent elective abdominal aortic surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 11) via Ovid; Ovid MEDLINE (from inception to week 1 November 2010); and EMBASE (from inception to week 1, November 2010). The original search was performed in 2004. We assessed non-English language reports and contacted researchers in the field. We did not seek unpublished data.

SELECTION CRITERIA

We included all randomized and quasi-randomized controlled trials comparing postoperative epidural analgesia and postoperative systemic opioid-based analgesia for adult patients who underwent elective open abdominal aortic surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information and data.

MAIN RESULTS

We included 15 trials that involved 1297 patients (633 patients received epidural analgesia and 664 received systemic opioid analgesia) in this review. This included one trial we found in our updated search and one trial from our original review that had been awaiting translation. The epidural analgesia group showed significantly lower visual analogue scale scores for pain on movement (up to postoperative day three) regardless of the site of the epidural catheter and epidural formulation. The postoperative duration of tracheal intubation and mechanical ventilation was significantly shorter, by about 48%, in the epidural analgesia group. The overall event rates of myocardial infarction, acute respiratory failure (defined as an extended need for mechanical ventilation), gastrointestinal complications, and renal complications were significantly lower in the epidural analgesia group.

AUTHORS' CONCLUSIONS

Epidural analgesia provides better pain relief (especially during movement) in the period up to three postoperative days. It reduces the duration of postoperative tracheal intubation by roughly half. The occurrence of prolonged postoperative mechanical ventilation, myocardial infarction, gastric complications and renal complications was reduced by epidural analgesia. However, current evidence does not confirm the beneficial effect of epidural analgesia on postoperative mortality and other types of complications.

Epidural pain relief versus systemic opioid-based pain relief for abdominal aortic surgery

BACKGROUND

Epidural analgesia offers greater pain relief compared to systemic opioid-based medications, but its effect on morbidity and mortality is unclear.

OBJECTIVES

To assess the benefits and harms of postoperative epidural analgesia in comparison with postoperative systemic opioid-based pain relief for adult patients who underwent elective abdominal aortic surgery.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials via OVID (CENTRAL) (The Cochrane Library, Issue 3, 2004); OVID MEDLINE (1966 to July 2004); and EMBASE (1980 to June 2004). We assessed non-English language reports and contacted researchers in the field. We did not seek unpublished data.

SELECTION CRITERIA

We included all randomized controlled trials comparing postoperative epidural analgesia and postoperative systemic opioid-based analgesia for adult patients who underwent elective open abdominal aortic surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information and data.

MAIN RESULTS

Thirteen studies involving 1224 patients met our inclusion criteria; 597 patients received epidural analgesia and 627 received systemic opioid analgesia. The epidural analgesia group showed significantly lower visual analogue scale for pain on movement (up to postoperative day three), regardless of the site of epidural catheter and epidural formulation. Postoperative duration of tracheal intubation and mechanical ventilation was significantly shorter by about 20% in the epidural analgesia group. The overall incidence of cardiovascular complication; myocardial infarction; acute respiratory failure (defined as an extended need for mechanical ventilation); gastrointestinal complication; and renal insufficiency was significantly lower in the epidural analgesia group, especially in trials that used thoracic epidural analgesia.

AUTHORS' CONCLUSIONS

Epidural analgesia provides better pain relief (especially during movement) for up to three postoperative days. It reduces the duration of postoperative tracheal intubation by roughly 20%. The occurrence of prolonged postoperative mechanical ventilation, overall cardiac complication, myocardial infarction, gastric complication and renal complication was also reduced by epidural analgesia, especially thoracic. However, current evidence does not confirm the beneficial effect of epidural analgesia on postoperative mortality and other types of complications.

The effect of low-dose heparin on hypercoagulability following abdominal aortic surgery

The effect of low-dose heparin on postoperative hypercoagulability was assessed using thrombelastography (TEG) in eighteen patients undergoing elective abdominal aortic surgery. Patients received unfractionated heparin 5000IU bd SC commencing on the first postoperative day. Native whole blood TEG was performed preoperatively and on day two postoperatively. A heparinase-modified TEG was performed at the same time as the native whole blood TEG on day two. There were no significant changes in the postoperative native whole blood TEG variables (r, K, alpha, MA) relative to preoperative controls. In contrast, there were significant decreases in r and K, and increases in alpha in the heparinase-modified TEGs postoperatively (P < 0.01). There were significant differences between the postoperative native whole blood and heparinase-modified TEGs for all TEG variables (P < 0.01). The results indicate that low-dose heparin reduces postoperative hypercoagulability following abdominal aortic surgery as assessed by thrombelastography.

Changes in platelet count, coagulation and fibrinogen associated with elective repair of asymptomatic abdominal aortic aneurysm and aortic reconstruction for occlusive disease

BACKGROUND

Mortality and morbidity following aortic surgery, particularly repair of ruptured abdominal aortic aneurysm (AAA), is frequently associated with the development of coagulopathy.

OBJECTIVES

To examine changes in platelet count (PC), fibrinogen, and coagulation in patients undergoing elective repair of asymptomatic abdominal aortic aneurysm (AAA) and aortic surgery for occlusive disease.

DESIGN

Prospective clinical study in a University Department of Vascular Surgery.

PATIENTS

Thirty-three patients undergoing elective repair of asymptomatic AAA and 19 patients undergoing aortic surgery for occlusive disease.

METHODS

Full blood count (FBC), clotting screen, and fibrinogen measured pre-operatively; 6, 12, 24, 48 h postoperatively; and thereafter as clinically indicated in 23 consecutive patient's undergoing AAA repair (Group 1). Pre- and postoperative PC measured weekly for 4 weeks following operation in a further 10 consecutive patients undergoing AAA repair (Group 2) and perioperative PC measured in 19 consecutive patients undergoing aortic surgery for occlusive disease (Group 3).

RESULTS

Group 1: Preoperative haematological parameters were normal. There was no mortality. Postoperatively, 21 (91%) patients developed thrombocytopenia (PC < 150 x 10(9)/l). The postoperative fall in PC (median 90, range 12-160 x 10(9)/l) was significantly related to the duration of aortic cross-clamp (median 46, range 20-127 min, r2 = 0.33, p < 0.01). At 10 days all patients had developed thrombocytosis (PC > 350 x 10(9)/l) Postoperatively, by 48 h, 17 (74%) patients had developed hyperfibrinogenaemia. One patient suffered a myocardial infarction associated with a PC of 105 x 10(9)/l and a fibrinogen of 7.2 g/l. GROUP 2: In a further 10 patients undergoing AAA repair postoperative thrombocytosis was found to persist for several weeks in five of nine survivors. GROUP 3: Patients undergoing aortic surgery for occlusive disease had significantly higher preoperative PC than AAA patients (median 292, range 179-251 x 10(9)/l vs. median 204, range 140-293 x 10(9)/l, p < 0.01).

CONCLUSIONS

Patients undergoing elective repair of AAA demonstrate similar, albeit less dramatic, changes in platelet count to those we have previously reported in patients undergoing repair of ruptured AAA. Aortic clamping leads to platelet sequestration and thrombocytopenia in the early postoperative period. Later, patients develop hyperfibrinogenaemia and thrombocytosis which may persist for several weeks. Similar changes are seen in patients undergoing aortic surgery for occlusive disease. These changes may represent a hypercoagulable state that predisposes these patients to thrombotic complications.

Anesthesia type does not influence early graft patency or limb salvage rates of lower extremity arterial bypass

PURPOSE

The effect of anesthesia type on 30-day graft patency and limb salvage rates was evaluated in patients who underwent femoral to distal artery bypass.

METHODS

Of 423 patients randomly assigned to receive general, spinal, or epidural anesthetic, 76 did not meet protocol standards and 32 had inadequate anesthesia. A chart review of the remaining 315 patients was undertaken to obtain surgical information not recorded in the original study. All patients were monitored with radial and pulmonary artery catheters. After surgery, patients were in a monitored setting for 48 to 72 hours and had graft function assessments hourly during the first 24 hours and then every 8 hours until discharge.

RESULTS

Fifty-one patients were lost to follow-up (15 general, 22 spinal, 14 epidural). Baseline clinical characteristics were similar for the three groups except prior carotid artery surgery, which was more common in the spinal group. Indications for surgery were also similar except for a higher incidence of nonhealing ulcer in the epidural group. There were no differences among groups for 30-day graft patency with or without reoperation, 30-day graft occlusion, death, amputation, or length of hospital stay.

CONCLUSION

These results suggest that the type of anesthetic given for femoral to distal artery bypass does not significantly affect 30-day occlusion rate, limb salvage rate, or hospital length of stay.