R.K. Vohra

Randomized clinical trial comparing the effects on renal function of hydroxyethyl starch or gelatine during aortic aneurysm surgery

The optimal colloid for renal protection during abdominal aortic aneurysm (AAA) surgery is not known. This study compared the effects of two hydroxyethyl starch (HES) solutions and gelatine on perioperative renal function.

Splanchnic oxygenation in patients undergoing abdominal aortic aneurysm repair and volume expansion with eloHAES

BACKGROUND Gastric intramucosal pH (pHi), a surrogate marker of splanchnic oxygenation, falls following abdominal aortic aneurysm surgery. AIM To investigate the effects of volume expansion with hydroxyethyl starch (eloHAES) on splanchnic perfusion compared to another colloid such as gelofusine. PATIENTS AND METHODS Twenty-two consecutive patients undergoing AAA repair were randomised to receive either eloHAES or gelofusine as plasma expanders. Tissue oxygenation was monitored (10 gelofusine and 12 eloHAES) indirectly by measuring pHi using a nasogastric tonometer. RESULTS Compared to the eloHAES group, the fall in pHi was significantly greater in the gelofusine group at clamp release (7.29 vs 7.33, P=0.003) and at 4 h following clamp release (7.29 vs 7.33, P=0.03). There was a good inverse correlation between the lowest pHi and the peak serum interleukin-6 (r(s)= -0.47, P=0.03). By multivariate analysis, the only factor that influenced the pHi was the type of colloid used (F=5.54, P=0.005). The eloHAES treated patients required significantly less colloid on the first postoperative day (3175 +/- 175 vs 4065 +/- 269 ml, P=0.01). CONCLUSION In patients undergoing abdominal aortic aneurysm repair, plasma expansion with eloHAES improves microvascular perfusion and splanchnic oxygenation.

Mechanisms of the anti-inflammatory effects of hydroxyethyl starch demonstrated in a flow-based model of neutrophil recruitment by endothelial cells.

Objective:To determine whether plasma volume expander hydroxyethyl starch (HES) may protect against reperfusion injury through an ability to reduce neutrophil recruitment. Design:An in vitro study using paired comparisons of adhesion of flowing neutrophils. Setting:A collaboration between clinical and basic science departments in a university hospital. Subjects:Neutrophils and cultured human umbilical vein endothelial cells (HUVEC). Interventions:Treatment with HES (average molecular weight of 200 kd and substitution of 0.62) at clinically relevant concentrations or with gelatin solution (average molecular weight of 30 kDa) of comparable viscosity. Measurements and Main Results:Glass capillaries were coated internally with either purified adhesion molecules or HUVEC, which were treated with tumor necrosis factor-&agr; in the presence or absence of HES. Neutrophils were perfused over these surfaces (with or without HES) and their recruitment quantified by video microscopy. Expression of adhesion molecules and of the chemokine interleukin-8 by HUVEC were analyzed by enzyme-linked immunosorbent assay and quantitation of messenger RNA. HES over a wide range of concentrations had no effect on selectin- or integrin-mediated adhesion of neutrophils. However, when HUVEC were cultured with 1.5% wt/vol HES, neutrophil capture induced by low-dose (1 unit/mL) tumor necrosis factor-&agr; and transendothelial migration induced by high-dose (100 units/mL) tumor necrosis factor-&agr; were significantly inhibited (p < .05, in each case). The effects were linked with reductions in expression of E-selectin and interleukin-8 by HUVEC at these respective tumor necrosis factor-&agr; concentrations (p < .05, in each case). Gelatin (2% wt/vol) had no significant effect in assays with HUVEC. Conclusions:Application of HES to HUVEC exerts an inhibitory effect on different stages of neutrophil recruitment, depending on the level of the inflammatory stimulus. These effects are associated with reduced adhesion molecule expression and chemokine production. In vivo, comparable effects might protect against complications associated with reperfusion injury.

Randomized Trial Comparing Quixil Surgical Sealant with Kaltostat Hemostatic Dressing to Control Suture Line Bleeding after Carotid Endarterectomy with ePTFE Patch Reconstruction

Following carotid endarterectomy (CEA), patch angioplasty provides a significant reduction in the risk of perioperative complications. The expanded polytetrafluoroethylene (ePTFE) patch is strong, is resistant to infection, and has low thrombogenicity; but it remains unpopular because of its tendency of prolonged bleeding at the suture line. We aimed to investigate whether the application of Quixil sealant to the suture line could improve the time to achieve hemostasis and reduce local blood loss when compared to a standard topical hemostat Kaltostat. A prospective, randomized trial of 20 patients undergoing CEA was undertaken. Patients were randomized to receive either Quixil sealant (treatment group) or topical Kaltostat (controls) as a hemostatic agent to the patch suture line. Hemostasis was defined as no bleeding at the suture line for 1 minute. Statistical analysis was performed using the Mann-Whitney test. The two groups had a similar age and sex distribution. The mean age was 71 years, and there were seven men and three women in each group. The time to achieve hemostasis was significantly lower in the Quixil group (median 2.5 minutes, range 1–4 minutes) compared to the controls (median 17 minutes, range 7–59 minutes) (p < 0.001). Blood loss after clamp release was also significantly reduced in the Quixil group; median 24.5 ml (range 5.5–105.0 ml) versus 203 ml (range 54.5–817.0 ml) (p < 0.001). This study has demonstrated that Quixil human surgical sealant is an effective sealant of ePTFE patch suture holes and does not compromise the patch repair. It could be used during other vascular procedures involving ePTFE.

Splanchnic Microcirculation Protection by Hydroxyethyl Starches During Abdominal Aortic Aneurysm Surgery

OBJECTIVE To specifically compare the effect of two hydroxyethyl starches (HES) on the splanchnic microcirculation and systemic inflammation during abdominal aortic aneurysm (AAA) surgery. MATERIALS AND METHODS A prospective randomised study was carried out on 62 patients who received HES of molecular-weight 200 kDa (HES200/0.62), 130 kDa (HES130/0.4) or gelatine for 24h peri-operatively. Gastric-mucosal pHi (GpHi) and anti-endotoxin antibody were used as markers of splanchnic perfusion and endotoxaemia respectively. C-reactive protein (CRP) and lung-injury score (LIS) were used as markers of systemic inflammation and end-organ dysfunction respectively. Data was collected prospectively. RESULTS The drop in GpHi was least with HES200/0.62 compared to HES130/0.4 and gelatine at reperfusion (7.32 vs 7.28 and 7.28, p=0.017 and 0.009 respectively) and compared to gelatine at 2h as well (7.43 vs 7.28, p=0.001). GpHi dropped less with HES130/0.4 compared to gelatine at 2h (7.39 vs 7.28, p=0.002). Endotoxaemia increased only with gelatine. CRP was lower with HES200/0.62 (178 mg/mL) than gelatine (221 mg/mL) and HES130/0.4 (223 mg/mL) at 48 h (p=0.049 and p=0.009 respectively). There was no difference in LIS but ventilation duration was less with HES200/0.62 compared with gelatine (4 vs 11h, p=0.012). CONCLUSION During AAA surgery, HES200/0.62 provides the best splanchnic microcirculation protection, also reducing inflammation and duration of ventilation.

Ruptured inflammatory aortic aneurysm with aortoenteric fistula and infected with Streptococcus pneumoniae: a review of the literature

We present a case report of a 65-year-old gentleman who presented with an aortoenteric fistula along with a review of the literature. He was found, in addition, to have an inflammatory infrarenal aortic aneurysm with a posterior rupture. Cultures of the aneurysm sac confirmed a Streptococcus pneumoniae infection. The patient had previously presented with pneumonia. Antibody testing revealed an isolated pneumococcal IgG deficiency. The case demonstrates the diverse pathologies associated with aortic aneurysms and a need to be vigilant and occasionally expect the unusual.

Temporal artery biopsy: impact on the clinical management of patients

ObjectivesTemporal artery biopsy (TAB) is requested in an attempt to confirm the diagnosis of temporal arteritis (TA). Patients symptoms and signs are highly variable and TA is often focal and potentially missed in a small biopsy. The study aimed to determine if TAB helps in the management of patients with suspected TA.MethodsThe case records of sixty-six consecutive patients who had undergone temporal artery biopsy were recalled and examined for presenting symptoms, management, therapy, results and outcome.ResultsThere were 23 men and 43 women with a mean age of 70.2 and 71.1 years respectively. Presenting symptoms varied with unilateral headache in 53, scalp tenderness in 16, muscle weakness in 10, visual disturbance in 16, jaw claudication in 5 and peri-orbital pain in 1 patient. The temporal artery was tender in 21 patients and thickened in 4 patients. Thirty-eight patients were commenced on steroids prior to biopsy and 6 more before the histology became available. Only 8% of biopsies were positive for TA. Of the patients started on steroids with a negative biopsy, the steroids were continued in 26 and stopped in 9. In the patients not put on steroids [22], biopsy was positive in 2; they were commenced on steroids. Therefore, the histological diagnosis resulted in a change in patient management in only 18% of patients.ConclusionThe results of TAB do not appear to affect the clinical management of most patients with suspected temporal arteritis. We must therefore question the routine use of this invasive investigation.