Tonometer pH_i Monitoring of Free Jejunal Grafts following Pharyngolaryngoesophagectomy for Hypopharyngeal or Cervical Esophageal Cancer

Abstract

Background/Aims: Graft failure is a critical complication associated with vascular occlusion in esophageal reconstruction with a free jejunal graft following pharyngolaryngoesophagectomy. In this study, we evaluated the usefulness of intramucosal pH (pH_i) measurement using a tonometer to assess the graft viability. Methods: Two consecutive studies, the early phase study and the late phase study, were performed. Nineteen patients who underwent free jejunal transfer were enrolled in the early phase study before 1999 to determine the critical pH_i value. In the late phase study after 2000 (n = 16), anticoagulant treatment to prevent graft necrosis was performed in the patients having a pH_i value under the critical level. Results: In the early phase study, vascular obstruction was not seen in 16 patients with pH_i >7.10. Of 3 patients with pH_i <7.10, 2 underwent regrafting because of jejunal graft necrosis by vascular obstruction. In the late phase study, reoperation was not required in 3 of 4 patients with pH_i <7.10. Intraoperative vascular occlusion was found in 1 patient with a decline in pH_i value and anticoagulant treatment was effective in 2 others. Conclusion: The pH_i measurement using a tonometer is useful for finding vascular problems in free jejunal grafts.

How to assess intestinal viability during surgery: A review of techniques

“…After an equilibration period, pCO2 of the saline filling the balloon is proportionate to the intestinal mucosal pCO2. This value and that of the arterial bicarbonate are then used in the Henderson-Hasselbach equation to calculate the intramucosal pH: pHi = 6.1 + log10 [(HCO3)/(0.03 x pCO2 X F)], in which F is a time-dependent correction factor and [HCO3] is the actual bicarbonate concentration (mmol/L) of the arterial blood sample [75,76] . Kamiya and coworkers monitored pHi levels in the intestinal lumen using a tonometer intraoperatively and after the operation [75] .…”

“…This value and that of the arterial bicarbonate are then used in the Henderson-Hasselbach equation to calculate the intramucosal pH: pHi = 6.1 + log10 [(HCO3)/(0.03 x pCO2 X F)], in which F is a time-dependent correction factor and [HCO3] is the actual bicarbonate concentration (mmol/L) of the arterial blood sample [75,76] . Kamiya and coworkers monitored pHi levels in the intestinal lumen using a tonometer intraoperatively and after the operation [75] . 35 patients who underwent free jejunal transfer following pharyngolaryngoesophagectomy for laryngeal, hypopharyngeal and cervical esophageal cancer were enrolled in the prospective observational study.…”

Quantitative assessment of the free jejunal graft perfusion

“…Most of patients undergo preoperative chemoradiotherapy, which might affect the cervical blood vessels for the anastomosis possibly leading to postoperative anastomotic stenosis or thromboembolic occlusion. Therefore, significant efforts have been made to establish a reliable postoperative monitoring method, such as monitoring of intramucosal pH by tonometer [23], endoscopic observation [24], and Doppler ultrasound monitoring of FJG [24]. Some surgeons prefer to monitor flaps through the small window of the neck incision until the second or third postoperative day [4,25].…”

A “watch window” technique for monitoring buried free jejunum flaps during circumferential pharyngolaryngectomy reconstruction

“…Indirect monitoring methods include the use of a buried monitor probe, external surface monitoring with an ultrasonic Doppler [24], application of a monitoring flap using an isolated segment of the jejunum supplied by the same vascular pedicle [15,25], intramucosal PCO 2 measurement [21], or tonometric pHi monitoring [22].…”

“…Using a laryngeal fiberscope, creating a surgical window [14], or externalising an indicator segment [15,16] allows for direct observation of peristalsis and mucosal or serosal colour. Indirect monitoring methods include the use of implantable and handheld Dopplers [17][18][19][20], intramucosal PCO 2 measurement [21] and tonometric pHi monitoring [22]. However, these methods are subject to various technical or validity problems.…”