Postoperative pulmonary complications (PPC) are a major cause of perioperative morbidity and mortality. The definitions of PPC include several major categories of clinically significant complications, including atelectasis, respiratory infection, postoperative respiratory failure and exacerbation of chronic lung disease. To prevent PPC, intraoperative lung protective ventilation, a postoperative lung expansion maneuver, a high flow nasal cannula (HFNC) and noninvasive positive pressure ventilation (NPPV) can be applied. Regarding lung protective ventilation, low tidal volume ventilation (LTVV) with moderate PEEP and the lung recruitment maneuver are more effective for preventing PPC than LTVV alone. Early mobilization, chest physiotherapy, and an oral hygiene bundle approach can reduce PPC. Although HFNC has a good tolerability, it should not be considered a standard measure to prevent PPC in high-risk patients because the PEEP effect attributable to HFNC is not sufficient to re-expand the collapsed lung. The benefit from applying NPPV is the lung recruitment effect, thereby reducing the risk of reintubation and pneumonia in high-risk patients. However, NPPV is difficult to use for long periods of time because of its poor tolerability. Close monitoring of the patient’s respiratory status during the use of HFNC or NPPV for postoperative respiratory failure to avoid delayed reintubation.

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With the rapidly aging population in Japan, the number of geriatric patients undergoing surgical procedures under anesthesia is expected to increase. Furthermore, postoperative neurocognitive disorders, such as postoperative delirium (POD) and cognitive dysfunction (POCD), are now well-recognized as the most frequent complications of surgery, especially in geriatric patients. More importantly, epidemiological studies consistently show that POD/POCD are not transient phenomena, but are associated with long-term disability and increased mortality rates. Although POD and POCD are considered distinct clinical entities, recent preclinical and clinical findings suggest that neuroinflammation is a common underlying mechanism involved in the development of these disorders. Neuroinflammation is characterized by microglia activation and under increased brain levels of pro-inflammatory cytokines, such as TNF-α and IL-1β. Particularly, microglia in a normal aged brain is reportedly shifted towards an inflammatory phenotype, known as “microglia priming”. The microglia priming in the hippocampus may make elderly surgical patients highly susceptible to the development of neuroinflammation and related cognitive disorders following a peripheral immune challenge. Furthermore, during the perioperative period, many factors including general anesthetics/sedatives, surgery-related systemic inflammation, an acute stress response, and nerve injury can contribute to the development of neuroinflammation via both neuronal and humoral pathways. Therefore, to prevent and manage postoperative neurocognitive disorders, it is crucially important to minimize these intrinsic or iatrogenic risk factors. This review provides a pathophysiological overview of postoperative neurocognitive disorders and current perspectives on prevention, treatment, and intervention strategies.

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Excessive spontaneous inspiratory efforts in veno venous extracorporeal membrane oxygenation (VV-ECMO) may exacerbate lung injury by generating elevated transpulmonary pressure. Case 1 was of a 25-years-old woman. VV-ECMO was initiated for severe acute respiratory distress syndrome (ARDS) with miliary tuberculosis. On day 6, end inspiratory transpulmonary pressure (EIP_L) was elevated to 24 cmH₂O after beginning awaking; after that, EIP_L was successfully reduced to 7 cmH₂O by continuous deep-sedation again. Case 2 was of a 51-years-old man. VV-ECMO was initiated for influenza-related ARDS with air leak syndrome. On day 4, EIP_L was maintained less than 20 cmH₂O after beginning awake ECMO; thus, spontaneously breathing was preserved. Considering that controlled efforts for spontaneous breathing by the two patients helped them recover from severe ARDS and air leak syndrome without lung injury, esophageal pressure monitoring during VV-ECMO is a good indicator to detect strong spontaneous effort and to decide whether to continue spontaneous breathing or not.

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Patient: A 32-year-old man with severe obesity and a BMI of 51.7 was hospitalized because of pneumonia. He underwent respiratory management with a mechanical ventilator; however, because the respiratory management was difficult (P/F ratio was around 50), he was transferred to the ICU. Transpulmonary pressure was monitored, and in order to address the decreased thoracic compliance and pressure on the diaphragm due to severe obesity, we conducted respiratory management with high PEEP, which resulted in an improvement in the respiratory condition. Furthermore, when we conducted continuous negative abdominal pressure management to improve the pressure on the diaphragm, the end-expiratory transpulmonary pressure was elevated under the same respiratory condition. Discussion: Avoiding lung injury related to the use of a mechanical ventilator is important during the management of respiratory failure, and lung-protective ventilation and the open lung approach are the primary strategies adopted for this purpose. Because of the high abdominal pressure in patients with severe obesity, alveolar collapse is enhanced by the decrease in transpulmonary pressure due to the pressure on the diaphragm. In the present patient, abdominal pressure was decreased because of continuous negative abdominal pressure management, and an elevation of end-expiratory transpulmonary pressure was observed under the same respiratory condition. We believe that the obtained change can improve atelectasis, thereby benefiting the open lung.

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A 33-year-old previously healthy man presented with ventricular fibrillation due to acute myocardial infarction. The patient was given coronary recanalization therapy under extracorporeal cardiopulmonary resuscitation by using veno arterial extracorporeal membrane oxygenation (VA-ECMO). As a result, his spontaneous circulation returned and he was admitted to the ICU. In the ICU, his hemodynamics stabilized and VA-ECMO was removed. However, he experienced acute kidney injury due to right lower leg compartment syndrome and rhabdomyolysis. Thus, he was treated with continuous hemodiafiltration. After 16 days in the hospital, severe hematochezia was observed. An emergency endoscopy of the sigmoid colon revealed multiple ulcers, which were suspected to be due to ischemic colitis. The hematochezia was uncontrollable; therefore, we urgently performed a left hemicolectomy and then Hartmann's procedure three days later. After 21 days in the hospital, the test results for cytomegalovirus (CMV) antigenemia were positive (6/25,000 cells). Histopathology revealed nuclear inclusions characteristic of CMV enteritis and ganciclovir therapy was initiated. After 32 days in the hospital, we discharged the patient from the ICU. We report a case of colitis presenting with severe hematochezia that developed in a previously healthy adult.

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The purpose of this study was to clarify participation and recognition of the nurse for ventilator weaning. A mail survey was sent to 1,476 nurses of Japan Academy of Critical Care Nursing. Four individuals (1.3%) involved in the change of ventilation settings answered “nurses to judgment and operation” questionnaire. A total of 259 (84.4%) individuals agreed that a ventilator weaning protocol was required and 227 individuals (73.9%) were in the favor of nurses undergoing practice for ventilator weaning.

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[in Japanese]

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