Does increasing the arterial blood pressure at the end of a laparoscopic gastric bypass relates the number of postoperative haemorrhages? 

Cécile TENEY MD 1,3, Jan MULIER MD PhD1, Bruno DILLEMANS MD 2, Michel VAN DYCK MD3
1 Dep.  Anaesthesiology, AZ Sint Jan Brugge-Oostende, Belgium.
2 Dep. General Surgery, AZ Sint Jan Brugge-Oostende, Belgium.
3Dep. Anaesthesiology Cliniques universitaires Saint Luc, UCL, Brussels, Belgium.

Introduction
From 2004 till 2008 (1) a large number of gastric bypass patients have had postoperative haemorrhages (92 haemorrhages on 2903 pt or 3,2%) requiring frequent surgical revision (29 revisions 0,9%) In 2009, we instructed too increase the systolic arterial blood pressure (SAP) to 140 mmHg in every patient and so we reduced dramatically the number of haemorrhages (1%) and surgical revisions (0,1%) in 2010.  Other surgical mesures have also been taken over the years (staplers, surgical protocols,…)
The following years some post operative haemorrhages remained. Did these patients with haemorrhage have an insufficient increase in blood pressure intra operative or did we not treat their postoperative hypertension sufficiently? 1)

Methods
We investigated the haemorrhages retrospective in all patients (5237) getting a laparoscopic gastric bypass from 2011 till mid 2015 and noted the highest SAP reached before ending surgery and the highest SAP reached in the PACU. The ethical committee validated retrospective analysis for this patient group. Logistic regression is used to found factors having effect on haemorrhage and having effect on achieving blood pressure increase intra operative and post operative.

Results & discussion
54 patients on 5237 had a haemorrhage (1%) with 11 revisions (0,2%). There is a demographic difference between patients bleeding and those not bleeding for age and gender, not for BMI, OSAS, hypertension or diabetes. 
More opioids given intra operative and post operative increases the risk for haemorrhage.
The patients bleeding post operative had a mean maximum SAP at end of operation of 122 mmHg, significant lower than 130 mmHg for patients not bleeding and had a mean maximum SAP in the PACU of 145 mmHg significant higher than 132 mmHg. Only 30% of the patients reached 140 mmHg or more and 20 % did not reach 120 mmHg! 
Intra operative pressure increase is easier reached in younger patients (p=0,013), with hypertension (p<0,001) and when opioid free anaesthesia (p<0,001) or lowest dose of Sufentanyl (p=0,017) is used intra operative. 
Blood pressures are higher in older (p=0,949), male (p=0,019) patients with hypertension (p=0,011) getting more opioids intra (p<0,001) and post operative (p=0,007) while anaesthesia experience is not significant (p=0,067).  

Conclusion 
The aim to increase the SAP to 140 mmHg at the end of a lap bypass is not achieved in every patient. More haemorrhages happen persistant low intra operative blood pressure and high postoperative blood pressure. Opioids use intra and post operative reduces optimal SAP, so it increases haemorragic complications. 

References
1. Standardization of the Fully Stapled Laparoscopic Roux-en-Y Gastric Bypass for Obesity Reduces Early Immediate Postoperative Morbidity and Mortality: A Single Center Study on 2606 Patients.   B Dillemans et al  2009 Obes Surg.

Does increasing the arterial blood pressure at the end of a laparoscopic gastric bypass reduces the number of postoperative haemorrhages?