link. Web viewWhile the available evidence suffered from risk of bias, indirectness, and clinical and methodological heterogeneity, it does suggest that negative

Supplement 29: Should We Preferentially Use NPWT for Temporary Abdominal

Closure?

Abdominal NPWT involves applying some degree of suction to an open abdominal

wound, using techniques that can be home-made or proprietary. Through use of a visceral drape

and constant negative wound pressure, this technique prevents visceral adherence to the

anterolateral abdominal wall while maintaining medial fascial traction, which may enhance

fascial closure rates among those with an open abdomen [29,[1, 2]]. It may also remove fluid

and pro-inflammatory cytokines from the peritoneum, which may reduce abdominal third space

volume, the systemic inflammatory response, and resultant organ dysfunction [29,[3, 4]]. As

some commercial techniques may afford more effective negative peritoneal pressure than others,

it may also be possible that outcomes differ between commercial and non-commercial types of

NPWT techniques (and even between commercial techniques). However, others have reported

concerns over associations between NPWT and recurrent ACS or intestinal or enteroatmospheric

fistulae [[5, 6]], especially among those with limited intra-abdominal fluid available for removal

[[7]].

Evidence Summary:

Table 1 affords the summary of findings for NPWT in general, while Table 2 presents

this for commercial NPWT only. No studies are yet available comparing commercial NPWT

techniques [the ABThera™ Open Abdomen Negative Pressure Therapy System versus the KCI

vacuum-assisted closure (VAC) device]. We identified four systematic reviews [[7-10]] (two of

which performed a meta-analysis of largely uncontrolled case series) [[8, 10]], two RCTs [[11,

12]], and nine cohort studies (three prospective/six retrospective) [[2, 3, 11-16]].

The available systematic reviews had conflicting conclusions. One concluded that

artificial burr and VAC techniques in general were associated with the best outcomes [[8]] while

another suggested that VAC techniques in general were most beneficial for patients with

contaminated open abdominal wounds (with either vacuum-assisted closure techniques or the

Wittmann patch having the most optimal outcomes in the absence of abdominal contamination)

[[10]]. Finally, two concluded that the data remained inconclusive [[7, 9]]. Moreover, although

both NPWT in general and commercial NPWT were associated with several improved surrogate

and clinical outcomes across some of the comparative studies of critically ill adults with open

abdominal wounds, each of these studies suffered from at least a moderate risk of bias. In

addition to enrolling small sample sizes, only one of the RCTs described allocation concealment,

and none of the studies described their indications for DC laparotomy or open abdominal

management in detail.

Recommendation:

The WSACS RECOMMENDS that in critically ill/injured patients with open

abdomens strategies utilizing negative pressure wound therapy should be used versus not

(Management Recommendation 6; GRADE 1C).

Rationale:

While the available evidence suffered from risk of bias, indirectness, and clinical and

methodological heterogeneity, it does suggest that negative pressure wound therapy has been

associated with improved outcomes as compared with alternate temporary abdominal closure

techniques. However, it remains unclear whether non-commercial (i.e. Barker’s vacuum pack

technique) or commercial (i.e. the KCI VAC or ABThera™ Open Abdomen Negative Pressure

Therapy system) techniques are most beneficial or cost-effective.

Table 1. Summary of Findings Table for Negative Pressure Wound Therapy

NPWT (KCI VAC, ABThera™, or Barker's vacuum pack technique) compared to an alternative temporary abdominal closure technique (mesh closure) for critically ill trauma or surgery patients with open abdominal woundsOutcomes No of Participants

(studies)Follow up

Quality of the evidence(GRADE)

Relative effect(95% CI)

Anticipated absolute effects

Risk with An alternative temporary abdominal closure technique (mesh closure)

Risk difference with NPWT (KCI VAC, ABThera™, or Barker's vacuum pack technique) (95% CI)

Mortality 51(1 RCT)

⊕⊕⊝⊝LOW1

due to imprecision

RR 1.0 (0.39 to 2.71)

250 deaths per 1000 0 fewer deaths per 1000(from 153 fewer to 428 more)

3000(68 studies)(systematic review of predominantly uncontrolled observational studies on NPWT)

⊕⊝⊝⊝VERY LOW2,4

due to risk of bias, indirectness

RR 0.75 (0.66 to 0.84)3

298 deaths per 10002 74 fewer deaths per 1000(from 48 fewer to 101 fewer)

Primary fascial closure

51(1 RCT)

⊕⊕⊕⊝MODERATE5

due to imprecision

RR 1.94 (0.83 to 4.49)

250 closures per 1000

235 more closures per 1000(from 43 fewer to 872 more)




RR 1.62 (1.49 to 1.76)3


221 more closures per 1000(from 175 more to 271 more)

Length of hospital or ICU stay - not reported

- - Not estimable

- -

Abdominal fistula(e)

51(1 RCT)

⊕⊕⊝⊝LOW6

due to risk of bias, imprecision

RR 3.87 (0.5 to 29.8)

50 fistuale per 1000 144 more fistulae per 1000(from 25 fewer to 1000 more)




RR 0.93 (0.72 to 1.21)3

75 fistulae per 10002 5 fewer fistulae per 1000(from 21 fewer to 16 more)

Intra-abdominal

51(1 RCT)

⊕⊕⊝⊝LOW1,6

RR 0.86 (0.45 to

450 abscesses per 1000

63 fewer abscesses per 1000

abscess(es) due to risk of bias, imprecision

1.66) (from 248 fewer to 297 more)



due to risk of bias, indirectness, imprecision

RR 0.86 (0.45 to 1.66)3

87 abscesses per 10002,7

12 fewer abscesses per 1000(from 48 fewer to 57 more)

Costs 51(1 RCT)

⊕⊕⊕⊝MODERATE8

due to risk of bias

The mean costs in the control groups was$474.24 per patient requiring open abdominal management

The mean costs in the intervention groups was$857.39 higher(0 to 0 higher)

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: Confidence interval; KCI, Kinetic Concepts Inc.; NPWT, negative pressure wound therapy; RR: Risk ratio; and VAC, vacuum-assisted closureGRADE Working Group grades of evidenceHigh quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.Very low quality: We are very uncertain about the estimate.1 Downgraded in quality as the 95% CI for the estimated RR included values suggesting the possibility of significant benefit or harm.2 In this systematic review, a weighted pooled outcomes analysis of the risk of various outcomes was performed using case series, cohort studies, and one randomized controlled trial. However, frequently the included studies did not perform a "head-to-head" comparison of alternate temporary abdominal closure techniques.3 These RR estimates are based on unweighted and indirect comparison data from a systematic review of case series of temporary abdominal closure with the NPWT versus mesh. 4 Limitations of the studies included in this systematic review include their often uncontrolled study design, lack of description of temporary abdominal closure indications, the frequently inadequate delineation of important co-variates known to influence mortality, fascial closure, or length of hospitalization, and the use of absolute or relative effect measures that were often unadjusted for important clinical or laboratory characteristics.5 Downgraded in quality as the 95% CI suggests a possible benefit of negative pressure wound therapy, but varies widely and includes the null value.6 Downgraded as all of the included patients were fitted with gastric or jejunal feeding tubes, and all of the abdominal fistulae developed in those treated wtih Barker's vacuum pack NPWT technique.7 In order to match the control group for the presented randomized trial, we reported the mortality risk for the mesh treatment group from the this systematic review and weighted pooled outcomes analysis of predominantly observational studies.8 Downgraded in quality as only supplies-related costs were considered in the analysis.

Table 2. Summary of Findings Table for Commercial Negative Pressure Wound Therapy

Commercial NPWT (KCI VAC, ABThera™) compared to Barker's vacuum pack technique for critically ill adults with open abdominal woundsOutcomes No of

Participants(studies)Follow up

Quality of the evidence(GRADE)

Relative effect(95% CI)

Anticipated absolute effects

Risk with Barker's vacuum pack technique

Risk difference with Commercial NPWT (KCI VAC, ABThera™) (95% CI)

Mortality 168(1 prospective cohort study of the ABThera™ NPT system)

⊕⊕⊕⊝MODERATE1,2

due to risk of bias, large effect

RR 0.48 (0.25 to 0.92)

263 deaths per 1000

137 fewer deaths per 1000(from 21 fewer to 197 fewer)

1437(systematic review of 23 case series)

⊕⊝⊝⊝VERY LOW3,4,5,6

due to risk of bias, inconsistency, indirectness, large effect

Not estimable

287 deaths per 1000

287 fewer deaths per 1000(from 287 fewer to 287 fewer)

Primary fascial closure 31(1 RCT of the KCI VAC)


due to indirectness, imprecision

RR 2.60 (0.95 to 7.1)


369 more closures per 1000(from 12 fewer to 1000 more)

168(1 prospective cohort study of the ABThera™ NPT system)

⊕⊝⊝⊝VERY LOW1,2,8

due to risk of bias, imprecision, large effect

RR 1.5 (1.1 to 2)


132 more closures per 1000(from 26 more to 263 more)

Length of hospital or ICU stay – Not reported by the one RCT or cohort study, or the systematic review of case series.

- - Not reported

Study populationSee comment -Moderate

-

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: Confidence interval; KCI, Kinetic Concepts Inc.; NPWT, negative pressure wound therapy; RR: Risk ratio; and VAC, vacuum-assisted closureGRADE Working Group grades of evidenceHigh quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.

Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.Very low quality: We are very uncertain about the estimate.

1 As this prospective multicenter cohort study is not yet published, its abstract data were taken from a systematic review of comparative studies. Therefore, a complete quality assessment is not yet available and these data could be linked with a risk of bias.2 In this prospective cohort study, the beneficial effect of the ABThera over Barker's vacuum pack technique on mortality was very large and on primary fascial closure was large.3 Limitations of the case series included in this systematic review include their often uncontrolled study design, lack of description of temporary abdominal closure indications, the frequently inadequate delineation of important co-variates known to influence mortality, fascial closure, or length of hospitalization, and the use of absolute or relative effect measures that were often unadjusted for important clinical or laboratory characteristics.4 The risk of mortality following temporary abdominal closure with the "VAC" (KCI VAC largely) varied from 7% to 33% in the case series included in this systematic review.5 In this systematic review, a weighted pooled outcomes analysis of the risk of various outcomes was performed using case series. However, the included studies did not perform a "head-to-head" comparison of alternate temporary abdominal closure techniques. 6 The reduction in the risk of mortality across individual case series was often considerably larger when indirectly compared across case series reporting on different temporary abdominal closure techniques.7 Although this RCT began by allocating patients to either Barker's vacuum pack technique or polyglactin mesh, the investigators later altered their study protocol and form of NPWT to the KCI VAC. Therefore, an indirect comparison of fascial closure between the KCI VAC and Barker's vacuum pack technique was possible.8 The 95% RR for primary fascial closure was close to, or included, the null value.

A Summary of Studies Table is Available On-line at Supplement A12 - Summary of Studies for Negative Pressure Wound Therapy

References

1. Miller PR, Thompson JT, Faler BJ, Meredith JW, Chang MC, (2002) Late fascial closure in lieu of ventral hernia: the next step in open abdomen management. J Trauma 53: 843-849

2. Miller PR, Meredith JW, Johnson JC, Chang MC, (2004) Prospective evaluation of vacuum-assisted fascial closure after open abdomen: planned entral hernia rate is substantially reduced. Ann Surg 239: 608-616

3. Batacchi S, Matano S, Nella A, Zagli G, Bonizzoli M, Pasquini A, Anichini V, Tucci V, Manca G, Ban K, Valeri A, Peris A, (2009) Vacuum-assisted closure device enhances recovery of critically ill patients following emergency surgical procedures. Critical care 13: R194

4. Kubiak BD, Albert SP, Gatto LA, Snyder KP, Maier KG, Vieau CJ, Roy S, Nieman GF, Peritoneal negative pressure therapy prevents multiple organ injury in a chronic porcine sepsis and ischemia/reperfusion model. Shock 34: 525-534

5. Rao M, Burke D, Finan PJ, Sagar PM, (2007) The use of vacuum-assisted closure of abdominal wounds: a word of caution. Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland 9: 266-268

6. Ouellet JF, Ball CG, (2011) Recurrent abdominal compartment syndrome induced by high negative pressure abdominal closure dressing. J Trauma 71: 785-786

7. Roberts DJ, Zygun DA, Grendar J, Ball CG, Robertson HL, Ouellet JF, Cheatham ML, Kirkpatrick AW, (2012) Negative-pressure wound therapy for critically ill adults with open abdominal wounds: A systematic review. The journal of trauma and acute care surgery 73: 629-639

8. Boele van Hensbroek P, Wind J, Dijkgraaf MG, Busch OR, Carel Goslings J, (2009) Temporary closure of the open abdomen: a systematic review on delayed primary fascial closure in patients with an open abdomen. World journal of surgery 33: 199-207

9. Stevens P, (2009) Vacuum-assisted closure of laparostomy wounds: a critical review of the literature. International wound journal 6: 259-266

10. Quyn AJ, Johnston C, Hall D, Chambers A, Arapova N, Ogston S, Amin AI, (2012) The open abdomen and temporary abdominal closure systems--historical evolution and systematic review. Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland 14: e429-438

11. Pliakos I, Papavramidis TS, Mihalopoulos N, Koulouris H, Kesisoglou I, Sapalidis K, Deligiannidis N, Papavramidis S, (2010) Vacuum-assisted closure in severe abdominal sepsis with or without retention sutured sequential fascial closure: a clinical trial. Surgery 148: 947-953

12. Bee TK, Croce MA, Magnotti LJ, Zarzaur BL, Maish GO, 3rd, Minard G, Schroeppel TJ, Fabian TC, (2008) Temporary abdominal closure techniques: a prospective randomized trial comparing polyglactin 910 mesh and vacuum-assisted closure. The Journal of trauma 65: 337-342; discussion 342-334

13. Perez D, Wildi S, Demartines N, Bramkamp M, Koehler C, Clavien PA, (2007) Prospective evaluation of vacuum-assisted closure in abdominal compartment syndrome and severe abdominal sepsis. Journal of the American College of Surgeons 205: 586-592

14. Patel NY, Cogbill TH, Kallies KJ, Mathiason MA, (2011) Temporary abdominal closure: long-term outcomes. The Journal of trauma 70: 769-774

15. Olejnik J, Sedlak I, Brychta I, Tibensky I, (2007) Vacuum supported laparostomy--an effective treatment of intraabdominal infection. Bratisl Lek Listy 108: 320-323

16. Wild T, Stremitzer S, Budzanowski A, Rinder H, Tamandl D, Zeisel C, Holzenbein T, Sautner T, (2004) ["Abdominal dressing" - a new method of treatment for open abdomen following secondary peritonitis]. Zentralblatt fur Chirurgie 129 Suppl 1: S20-23

Documents

link. Web viewWhile the available evidence suffered from risk of bias, indirectness, and clinical and methodological heterogeneity, it does suggest that negative