Liu R, Wang J, Zhao G, Su Z. Negative pressure pulmonary edema after general anesthesia: A case report and literature review. Medicine (Baltimore). 2019 Apr;98(17): e15389. doi: 10.1097/MD.0000000000015389.
It is widely accepted that the central mechanism of postoperative NPPE is related to rapid negative intrapleural pressure increasing due to forceful inspiration against the obstruction, which can be up to 10 times or more that of normal breathing.  A typical event leading to acute airway obstruction associated with postoperative NPPE is laryngospasm. Other procedure that increases the risk of NPPE includes oropharyngeal, head, and neck surgery. Five [8–12] of the reported 29 cases involved upper respiratory tract surgery, and 10 [1,3,6,7,13–18] of the cases involved head and neck surgery, which may be related to tissue swelling and the sensitive dilator muscle of the upper airway in head and neck surgeries.
Gulur P, et al. Retrospective analysis of the incidence of epidural haematoma in patients with epidural catheters and abnormal coagulation parameters. Br J Anaesth. 015;114(5): 808–811.
“Results: During the study period, 11 600 epidural catheters were placed. In the setting of abnormal coagulation parameters, 278 (2.4%) epidural catheters were placed and 351 (3%) were removed. Two epidural haematomas occurred; both patients had epidural catheters and spinal drains placed for vascular procedures with abnormal coagulation parameters after operatation. The haematomas occurred after removal of the catheters. Based on our study, the incidence of epidural haematoma in patients with abnormal coagulation parameters is 1 in 315 patients, with the lower limit of the 95% confidence interval at 87 and the upper limit at 2597.”
See also: Lee LO, Bateman BT, Kheterpal S, et al. Risk of Epidural Hematoma after Neuraxial Techniques in Thrombocytopenic Parturients: A Report from the Multicenter Perioperative Outcomes Group. Anesthesiology. 2017;126(6):1053–1063.
One discussion this week included the impact of abdominal binder on seroma formation.
Reference: Christoffersen MW, Olsen BH, Rosenberg J, Bisgaard T. Randomized clinical trial on the postoperative use of an abdominal binder after laparoscopic umbilical and epigastric hernia repair. Hernia. 2015 Feb;19(1):147-153. doi:10.1007/s10029-014-1289-6
Summary: Application of an abdominal binder is often part of a standard postoperative regimen after ventral hernia repair to reduce pain and seroma formation. However, there is lack of evidence of the clinical effects.