Detection of inadequate anastomotic perfusion with handheld vital microscopy in two patients during colorectal surgery.

INTRODUCTION: Anastomotic leakage is one of the most feared complications after gastrointestinal surgery. Assessment of anastomotic viability during surgery remains challenging. Sufficient bowel tissue perfusion is a requisite for anastomotic healing. Handheld vital microscopy (HVM) is a non-invasive technique that can directly visualize the intestinal microcirculation during surgery. PRESENTATION OF TWO CASES: Two patients underwent elective laparoscopic colorectal surgery. During surgery HVM was used to assess bowel perfusion prior to creation of a primary anastomosis. Although the bowel macroscopically appeared to be well perfused, HVM showed a severely compromised microcirculation. The colon was re-internalized and during the following minutes cyanosis of the bowel occurred which was visually determined by the surgeon. After dissection towards cranially, a new site for the primary anastomosis was chosen. The postoperative period was uncomplicated. DISCUSSION: Sufficient bowel tissue perfusion is often mentioned as key in the pathophysiology of anastomotic leakage. HVM is a technique that could potentially aid surgeons in the assessment of microcirculatory perfusion of the bowel during surgery. CONCLUSION: We report two cases undergoing colorectal surgery in which HVM showed merit in detecting compromised bowel perfusion before creation of a primary anastomosis.

Association between serosal intestinal microcirculation and blood pressure during major abdominal surgery.

Background: In clinical practice, blood pressure is used as a resuscitation goal on a daily basis, with the aim of maintaining adequate perfusion and oxygen delivery to target organs. Compromised perfusion is often indicated as a key factor in the pathophysiology of anastomotic leakage. This study was aimed at assessing the extent to which the microcirculation of the bowel coheres with blood pressure during abdominal surgery. Methods: We performed a prospective and observational cohort study. In patients undergoing abdominal surgery, the serosal microcirculation of either the small intestine or the colon was visualized using handheld vital microscopy (HVM). From the acquired HVM image sequences, red blood cell velocity (RBCv) and total vessel density (TVD) were calculated using MicroTools and AVA software, respectively. The association between microcirculatory parameters and blood pressure was assessed using Pearson's correlation analysis. We considered a two-sided P-value of <0.050 to be significant. Results: In 28 patients undergoing abdominal surgery, a total of 76 HVM images were analyzed. The RBCv was 335 ± 96 µm/s and the TVD was 13.7 ± 3.4 mm/mm2. Mean arterial pressure (MAP) was 71 ± 12 mm Hg during microcirculatory imaging. MAP was not correlated with RBCv (Pearson's r = -0.049, P = 0.800) or TVD (Pearson's r = 0.310, P = 0.110). Conclusion: In 28 patients undergoing abdominal surgery, we found no association between serosal intestinal microcirculatory parameters and blood pressure.

Intestinal Mucosal and Serosal Microcirculation at the Planned Anastomosis during Abdominal Surgery.

INTRODUCTION: Intestinal blood flow is often named as a key factor in the pathophysiology of anastomotic leakage. The distribution between mucosal and serosal microperfusion during surgery remains to be elucidated. OBJECTIVE: The aim of this study was to assess if the mucosal microcirculation of the intestine is more vulnerable to a surgical hit than the serosal microcirculation during surgery. METHODS: In an observational cohort study (n = 9 patients), the microcirculation of the bowel serosa and mucosa was visualized with incident dark-field imaging during surgery. At the planned anastomosis, the following microcirculatory parameters were determined: microvascular flow index (MFI), percentage of perfused vessels (PPV), perfused vessel density (PVD), and total vessel density (TVD). Data are presented as median (interquartile range [IQR]). RESULTS: Perfusion parameters and vessel density were significantly higher for the mucosa than the serosal microcirculation at the planned site for anastomosis or stoma. Mucosal MFI was 3.00 (IQR 3.00-3.00) compared to a serosal MFI of 2.75 (IQR 2.21-2.94), p = 0.03. The PPV was 99% (IQR 98-100) versus 92% (IQR 66-94), p = 0.01. The TVD was 16.77 mm/mm2 (IQR 13.04-18.01) versus 10.42 mm/mm2 (IQR 9.36-11.81), p = 0.01, and the PVD was 15.44 mm/mm2 (IQR 13.04-17.78) versus 9.02 mm/mm2 (IQR 6.43-9.43), p = 0.01. CONCLUSIONS: The mucosal microcirculation was preserved, while lower perfusion of the serosa was found at the planned anastomosis or stoma during surgery. Further research is needed to link our observations to the clinically relevant endpoint of anastomotic leakage.

Use of an Image Acquisition Stabilizer Improves Sidestream Dark Field Imaging of the Serosa during Open Gastrointestinal Surgery.

AIM: To investigate whether an image acquisition stabilizer (IAS) mounted on the sidestream dark field camera (SDF) during gastrointestinal surgery improves image stability and acquisition. METHODS: Serosal SDF imaging was compared with SDF imaging combined with an IAS (SDF + IAS) during gastrointestinal surgery. Stability was assessed as the image drift in pixels and the time to obtain stable images. The success rate was determined as the percentage of analyzable images after recording. The effect of negative pressure from the IAS was determined during single-spot measurements and by comparing microvascular parameters between groups. Data are presented as mean ± SD. RESULTS: Sixty serosal measurements were performed per group; 87% were successful in the SDF group and 100% in the SDF + IAS group (p = 0.003). Image drift in the SDF group was 148 ± 36 versus 55 ± 15 pixels in the SDF + IAS group; p < 0.001. Time to stable image was 96 ± 60 s in the SDF group versus 57 ± 31 s in the SDF + IAS group; p = 0.03. No effect of negative pressure was seen. CONCLUSION: The use of an IAS mounted on an SDF camera during serosal microvascular assessment improves the success rate of image acquisition and stability and reduces the time to stable image with no effect on the microcirculation.