Rationale: Excessive stress (distending pressure), strain (volume deformation), and drop in inspiratory alveolar pressure are proposed mechanisms for patient self-inflicted lung injury. Objectives: To dissect the influence of inspiratory effort, respiratory mechanics, and ventilation mode on lung stress, strain, and drop in inspiratory alveolar pressure; and explore their impact on oxygenation and lung compliance. Methods: International cohort study analyzing respiratory recordings (esophageal pressure) of patients with acute hypoxemic respiratory failure. Association between muscular pressure (Pmus), surrogates of stress (driving trans-alveolar pressure), strain (tidal volume), and inspiratory alveolar pressure relative to PEEP were explored with mixed-models, including interactions for ventilation mode, respiratory system elastance, and synchrony. Association between these and changes in oxygenation and lung compliance were explored. Measurements and main results: 60 patients from 15 centers represented 528 recordings (339,796 breaths). For each cmH(2)O Pmus increase there was an increase in driving trans-alveolar pressure (median[CI 95%] 0.28[0.27-0.29]cmH(2)O) and tidal volume (0.16[0.16-0.17]ml/kg of predicted body weight) and decrease in alveolar pressure (-0.25[0.24-0.6]cmH(2)O, p<0.001). Volume-control ventilation showed less increase in stress and strain surrogates than pressure-targeted modes, but more drop in alveolar pressure (p<0.001, Pmus:mode interaction). Breath-stacking was infrequent and associated with higher stress. Lower inspiratory alveolar pressure relative to PEEP was associated with subsequent worsening oxygenation (p=0.04) and higher stress with worsening lung compliance (p=0.023). Conclusion: Strong efforts are associated with high surrogates for lung stress, strain, and lower inspiratory alveolar pressure relative to PEEP, differently according to the mode of ventilation, being associated with subsequent worsening oxygenation and lung compliance.
In 2018, Inoue et al.1 introduced a systematic classification of the extent of dissection along the celiac axis (CA) and hepatic artery (HA) during open pancreaticoduodenectomy (PD). Three levels of perivascular dissection were defined according to surgical indication: level 1, limited organ resection without oncological dissection for benign or low-grade malignant lesions; level 2, formal lymphadenectomy with preservation of the perivascular nerve plexus for borderline or low-grade malignancies; and level 3, radical dissection, including perineural clearance for pancreatic cancer. As robotic PD is increasingly adopted, it should reproduce the same oncological standards established in open surgery.2–4 However, a standardized robotic technique capable of achieving all levels of the Inoue classification has not yet been clearly described. This video article aims to present a stepwise robotic approach to CA-HA dissection consistent with these principles. We present a comprehensive surgical video demonstrating a standardized robotic technique to achieve graded dissection of the CA and HA from level 1 to level 3. A supplementary video specifically illustrates advanced CA-HA dissection in the setting of vascular involvement requiring resection and reconstruction. Independently of the dissection level, three constant technical principles are systematically applied: (1) arterial control through vessel loop encirclement of the HA to avoid undue manipulation; (2) a selective and stepwise use of robotic instruments according to the depth of dissection, with monopolar curved scissors used to develop the superficial planes and Maryland bipolar forceps employed for precise periadventitial skeletonization of the arterial structures, thereby minimizing mechanical and thermal injury to the arterial wall. Energy sealing devices such as the vessel sealer (Intuitive Surgical, Sunnyvale, CA, USA) are used selectively and only away from major arteries, mainly for lymphatic or venous division and for final hemostasis once lymph nodes have been mobilized from the arterial wall. Alternatively, cold dissection with scissors can be used for precise arterial divestment, as previously described by Kauffman et al.5; (3) a structured four-hand robotic strategy involving two experienced hepato-pancreato-biliary surgeons to optimize exposure and vascular safety, with one surgeon operating at the console and a second surgeon assisting at the bedside to provide dynamic retraction, suction, and vascular control. All three levels of CA-HA dissection according to the Inoue classification were successfully achieved robotically. The robotic platform enabled stable magnified visualization and precise skeletonization along vascular and perineural planes. Advanced dissections, including circumferential perineural clearance, were feasible without intraoperative arterial injury or uncontrolled vascular complications, even during level 3 dissections or when vascular resection and reconstruction were required. A graded clearance of the CA and HA according to the Inoue classification can be safely reproduced during robotic PD, supporting standardization of oncological principles across different levels of perivascular dissection.
BACKGROUND:Complete situs inversus is a rare congenital condition characterized by mirror-image transposition of thoracoabdominal organs. Its association with pancreatic cancer is exceptional and poses significant technical challenges during pancreaticoduodenectomy, particularly due to vascular and anatomical variations.1-4 This video aims to illustrate the surgical strategy and key technical adaptations required to safely perform oncologic pancreaticoduodenectomy in this uncommon setting. METHODS:We present the case of a 68-year-old woman with a history of BRCA1-mutated breast cancer and complete situs inversus who presented with general deterioration and symptoms of high intestinal obstruction. Diagnostic work-up, including cross-sectional imaging and upper endoscopy with biopsy, confirmed a resectable pancreatic head adenocarcinoma with duodenal invasion in the setting of a complete common mesentery. The case was discussed in a multidisciplinary tumor board, and upfront surgical resection was recommended. A standard open pancreaticoduodenectomy was performed via midline laparotomy. Preoperative imaging was carefully analyzed to map vascular variations. The procedure included hepatoduodenal ligament dissection, lymphadenectomy of the celiac axis and hepatic artery stations, Kocher maneuver, and dissection of the mesenterico-portal axis. Particular attention was given to the identification and management of both venous and arterial jejunal trunks involved with the tumor. Reconstruction was achieved with pancreaticojejunostomy using a stented technique, hepaticojejunostomy with ductal enlargement, and precolic gastrojejunostomy, along with placement of a nasojejunal feeding tube. RESULTS:Complete oncologic resection (R0) was achieved. The postoperative course was complicated by Clavien-Dindo grade II events, including chylous ascites and grade A delayed gastric emptying, with a total hospital stay of 16 days. Final pathology demonstrated a poorly differentiated pancreatic adenocarcinoma staged as pT3N2, with 30 positive lymph nodes of 33 examined. CONCLUSIONS:Pancreaticoduodenectomy in patients with complete situs inversus and complete common mesentery is feasible and can be performed safely with meticulous preoperative planning and intraoperative adaptation to mirrored anatomy. A detailed understanding of vascular variations and a standardized stepwise approach are essential to ensure oncologic adequacy. This case highlights that, even in rare anatomical conditions, radical resection can be achieved without compromising surgical or oncological principles.
