Column Editor
Cornell Medicine, New York City
Executive Director, Surgical Infection
Society Foundation for Research and Education
SCIENTIFIC STUDIES COMMITTTEE
Wound Care for Perianal Abscess
Newton K, Dumville J, Briggs M, et al; PPAC2 Collaborators. Postoperative packing of perianal abscess cavities (PPAC2): randomized clinical trial. Br J Surg. 2022;109(10):951-957
Summary: This is a multicenter, single-blind, randomized controlled trial (two-group, parallel design) of 433 adult participants admitted to 50 hospitals in the United Kingdom for incision and drainage of their first primary perianal abscess of cryptoglandular origin. Mean age was 42 years. Participants were randomized postoperatively 1:1 to receive continued postoperative wound packing or non-packing, in order to minimize bias in the performance of the operation. (All patients received 24-hour initial packing for hemostasis.) External drains were not used. Excluded diagnoses included anal fistula, Fournier gangrene, and horseshoe abscess. Blinded data were collected via symptom diaries, telephone, and clinic visits over six months. The primary outcome was pain (mean maximum pain score within the first 10 days [100-point visual analog scale]). Pain scores were higher among 213 patients assigned to packing than among 220 allocated to non-packing (38.2 vs. 28.2; mean difference, 9.9; P<0.0001). Anal fistula incidence was low: 32 of 213 (15%) with packing versus 24 of 220 (11%) in the non-packing group (odds ratio [OR], 0.69; 95% CI, 0.39-1.22; P=0.20). Abscess recurrence was also low: seven of 213 (3%) with packing versus 13 of 223 (6%) in the non-packing group (OR, 1.85; 95% CI, 0.72-4.73; P=0.20).
Commentary: Every general surgeon who takes call, and certainly every colorectal surgeon, has encountered this common problem; empathizes with the protracted, painful, and messy recovery their patients endure; and wonders if there is a “better way.” Now, perhaps there is one. This pragmatic trial was re-powered after a planned interim analysis to detect a difference in mean maximum pain score of 20% with 85% power, so the trial is of adequate size. Operative techniques (except for no drains) were not standardized. Antibiotic management consisted of metronidazole monotherapy (standard in the United Kingdom), which was received by only 18% of patients (a marked difference from practice in the United States), demonstrating once again that antimicrobial therapy is but an adjunct to adequate surgical source control. Interestingly, neither patient satisfaction nor quality of life differed between the groups, so this maneuver provided only short-term benefit, but repetitive packing changes appear to be unnecessary.
Fluid Administration in Pancreatitis
de-Madaria E, Buxbaum JL, Maisonneuve P, et al; ERICA Consortium. Aggressive or moderate fluid resuscitation in acute pancreatitis. N Engl J Med. 2022;387(11):989-1000
Summary: At 18 centers (India, Italy, Mexico, and Spain), patients with acute pancreatitis were randomly assigned 1:1 to receive “aggressive” resuscitation (AR; 20 mL/kg bolus, followed by 3 mL/kg/h) or “moderate” resuscitation (MR; 10 mL/kg bolus if hypovolemic [no bolus if euvolemic] with lactated Ringer’s solution, followed by 1.5 mL/kg/h). Patients were assessed at 12, 24, 48, and 72 hours; fluid resuscitation was adjusted according to the patient’s clinical status. Fluid was discontinued when the patient tolerated oral feeding for eight hours. The primary outcome was the development of moderately severe or severe pancreatitis during the hospitalization. The main safety outcome was fluid overload. The powered sample size was 744; 249 patients were included in a planned interim analysis. The trial was halted for a safety signal without a significant difference in the incidence of moderately severe or severe pancreatitis (AR, 22.1% vs. MR, 17.3%; aRR, 1.30; 95% CI, 0.78-2.18; P=0.32). Incidence of fluid overload was AR, 20.5% versus MR, 6.3% (aRR, 2.85; 95% CI, 1.36-5.94; P=0.004). The median duration of hospitalization was not different between the groups (AR, six days; interquartile range [IQR], four to eight days and MR, five days; IQR, three to seven days).
Commentary: This study will attract attention by virtue of its publication venue, but there is less here than meets the eye. Skepticism is justified whenever a trial is stopped prematurely. Doing so underpowers a trial almost invariably. A majority of patients (61%) had gallstone pancreatitis, only 14 patients developed any organ dysfunction, only 10 patients required ICU care, and only eight patients developed infected pancreatic necrosis, so one can wonder how severely ill these patients were. No illness severity scores were reported; one-half of the patients were discharged within six days, which presumably included a laparoscopic cholecystectomy in many cases. Moreover, the primary outcome chosen here—progression of pancreatitis severity—is more correctly defined (using the authors’ criteria) as progression of organ dysfunction (e.g., acute kidney injury [AKI], acute respiratory failure). Based on the known pathophysiology of severe pancreatitis (local tissue damage caused by proteases, with a systemic inflammatory response), it may be counterintuitive to posit that withholding fluid can interdict disease progression. Is it the disease itself or the treatment (fluid) making things worse? Furthermore, fluid resuscitation can work at cross purposes (i.e., less fluid, if possible, for patients with respiratory failure may not be beneficial for AKI). Perhaps this is exemplary only of what happens when patients who aren’t very sick are given a lot of fluid. When patients are seriously or critically ill with pancreatitis, it is crucial to resuscitate with the goal of preserving renal function, because the combination of pancreatitis and AKI is especially deadly.
The Microbiome in Appendicitis
Vanhatalo S, Munukka E, Kallonen T, et al. Appendiceal microbiome in uncomplicated and complicated acute appendicitis: a prospective cohort study. PLoS One. 2022;17(10):e0276007
Summary: This prospective single-center analysis is a sub-study of the larger multicenter MAPPAC (Microbiology APPendicitis ACuta) trial that enrolled adult patients with CT- or clinically confirmed uncomplicated (uAA) or complicated acute appendicitis (cAA) to evaluate the appendiceal microbiome in acute appendicitis. Specimens of appendiceal fluid and mucosa were collected at surgery, or by colonoscopy if managed nonoperatively. Microbial composition of the appendiceal lumen was determined using 16S rRNA gene amplicon sequencing. A total of 118 samples (41 uAA and 77 cAA) were evaluated. After adjusting for age, sex, and body mass, alpha diversity in cAA was higher (Shannon, P<0.05; Chao1, P<0.01) compared with uAA. Microbial composition was also different between uAA and cAA (P<0.01). Species-poor appendiceal microbiota composition with specific predominant bacteria was present in some patients regardless of appendicitis severity.
Commentary: The contribution of appendiceal microbiota to appendicitis pathogenesis has been suggested, but differences between uAA and cAA are largely unknown. As part of the debate whether uAA is best managed non-operatively, it has been posited that uAA and cAA are distinct disease entities. Appendiceal microbiome profile differs between uAA and cAA, lending support to the hypothesis. Of course, it cannot be determined from these data whether alterations of the microbiome are causal or consequential to disease pathogenesis. However, the finding that loss of microbial diversity (overgrowth of potential pathogens) was independent of disease severity is worthy of additional study.
Originally published by our sister publication General Surgery News
