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Potential complications of using NSAIDs in cows undergoing caesarean section 

Clinical Scenario

You have just started a new job at a large farm animal practice. At your first vets meeting, the team discuss creating a new practice protocol for caesarian sections in dairy cows. There is much discussion and debate, particularly about the use of post operative analgesia. About half of the vets use NSAIDs routinely and the other half don't. Most of the vets want to use NSAIDs but some are worried about the possible increase in post operative complications due to the anti-prostaglandin effects of these drugs. You wonder if there is any evidence about the risks of using NSAIDs in cows following caesarean section......

3-Part Question (PICO)

In [cattle undergoing caesarean section] does [using NSAIDs compared to not using NSAIDs] [increase post operative complications]?

Search Strategy and Summary of Evidence

Search Strategy

MEDLINE(R) In-Process & Other Non-Indexed Citations and MEDLINE(R) 1946 to Present using the OVID interface

cow.mp. OR cows.mp. OR cattle.mp. OR bovine.mp. OR bovines.mp. OR bos.mp. OR exp Cattle/

AND

Caesar$.mp. OR Cesar$.mp. OR c section.mp. OR exp Cesarean Section/

AND

NSAID.mp. OR NSAIDs.mp. OR non steroidal anti inflammatory.mp. OR non steroidal anti inflammatories.mp. OR non steroidal antiinflammatory.mp. OR non steroidal antiinflammatories.mp. OR nonsteroidal anti inflammatory.mp. OR nonsteroidal anti inflammatories.mp. OR nonsteroidal antiinflammatory.mp. OR nonsteroidal antiinflammatories.mp. OR analgesia.mp. OR analgesias.mp. OR analgesic.mp. OR analgesics.mp. OR exp Anti-Inflammatory Agents, Non-steroidal/ OR exp Analgesics, Non-narcotic/ OR exp Analgesia/ OR exp Analgesics/

CAB Abstracts 1910 to Present using the OVID interface

cow.mp. OR cows.mp. OR cattle.mp. OR bovine.mp. OR bovines.mp. OR bos.mp. OR exp cows/ OR exp cattle/ OR exp Bos/

AND

Caesar$.mp. OR Cesar$.mp. OR c section.mp. OR exp caesarean section/

AND

NSAID.mp. OR NSAIDs.mp. OR non steroidal anti inflammatory.mp. OR non steroidal anti inflammatories.mp. OR non steroidal antiinflammatory.mp. OR non steroidal antiinflammatories.mp. OR nonsteroidal anti inflammatory.mp. OR nonsteroidal anti inflammatories.mp. OR nonsteroidal antiinflammatory.mp. OR nonsteroidal antiinflammatories.mp. OR analgesia.mp. OR analgesias.mp. OR analgesic.mp. OR analgesics.mp. OR exp non-steroidal antiinflammatory agents/ OR exp analgesics/

Search Outcome

MEDLINE

  • 11 papers found in MEDLINE search
  • 10 papers excluded as they don't meet the PICO question
  • 0 papers excluded as they are in a foreign language
  • 0 papers excluded as they are review articles/in vitro research/conference proceedings
  • 1 total relevant papers from MEDLINE

CAB Abstracts

  • 41 papers found in CAB search
  • 40 papers excluded as they don't meet the PICO question
  • 0 papers excluded as they are in a foreign language
  • 0 papers excluded as they are review articles/in vitro research/conference proceedings
  • 1 total relevant papers from CAB

Total relevant papers

1 relevant papers from both MEDLINE and CAB Abstracts

Summary of Evidence

Waelchi et al., 1999, Unknown

Title:

Effect of flunixin meglumine on placental expulsion in dairy cattle after a caesarean

Patient group:

98 cows (n=49) and heifers (n=49) with single live calves with firmly attached placenta to uterus at time of caesarean section. 49 animals were given flunixin and 49 animals were given saline. 

Study Type:

Randomised controlled trial

Outcomes:
  • Retained Foetal Membranes at 12 hours after surgery
Key Results:
  • 22/49 (44.9%) of cows/heifers treated with flunixin and 35/49 (71.4%) of cows/heifers treated with saline (placebo) had completely passed the placenta within 12 hours of surgery
  • 27/49 (55.1%) of cows/heifers treated with flunixin and 14/49 (28.6%) of cows/heifers treated with saline had retained foetal membranes at 12 hours post surgery
  • Therefore, cows/heifers treated with flunixin were significantly more likely to have retained foetal membranes than patients treated with placebo (p = 0.014)
  • The odds ratio was 3.07 (95% confidence interval, 1.33-7.09)
Study Weaknesses:
  • The basic data comparing groups prior to intervention is not given so it is unclear how the animals were distributed within the treatment groups for many factors e.g. cow vs heifer, breeds, previous calving and caesarean sections etc.
  • It is unclear if the veterinary surgeons administering treatment or assessing the outcomes were blinded, though saline was used as a placebo in the control group
  • No further data is provided beyond 12 hours post surgery (other sources define retained foetal membranes as those retained beyond 24 hours post partum)
  • It is unclear if the surgery was elective or not
  • Method of randomisation (other than they were randomised within pairs) not given
  • All statistical methods were not described
  • A sample size calculation was not reported but the authors use of a sequential analysis chart is appropriate to ensure adequate numbers of patients in the study without causing undue harm (see comments section below)
  • Ethical approval was not stated
  • Details of who funded the study were not given
Attachment:
Evidence appraisalEvidence appraisal

Comments

This paper is only a short communication so is limited in the amount of data that can be reported. There is not enough basic data given about the animals following randomisation into the two treatment groups and so they may have been significantly different prior to being injected. Therefore this means the difference between the groups at the end of the study may be due to the administration of flunixin or possibly unreported differences between the groups. Therefore the generalisability (external validity) of these results is unclear.

The paper focused on retained foetal membranes so there is no information about other post operative complications provided. It also included only one NSAID, flunixin, so it is not possible to draw conclusions about the effects of other, potentially more selective NSAIDs.

This paper was designed to provide further information about the role of prostaglandins as opposed to the risks of using NSAIDs. The benefits of the use of NSAIDs in cattle undergoing caesarean section were not the focus of this BET or the paper. As with all treatment decisions, the risks and benefits of the intervention should be considered prior to deciding whether to use these treatments or not. NSAIDs are often used for post operative analgesia following surgical procedures in cattle and post-operative pain has considerable welfare implications. 

As there was concern about the potential for the intervention in this trial to cause harm, rather than a sample size calculation a sequential analysis chart was used. In this form of sampling, analysis is done as the trial progresses with a pre-defined stop point if the intervention is found to cause harm. A trial will often finish earlier than when traditional sample size estimations are used.

Bottom line

It is unclear whether the use of NSAIDs will increase the risk of post operative complcations in all cattle following caesarean section. Based on the limited evidence found the use of flunixin meglumine may increase the frequency of retained foetal membranes in some cattle.

Disclaimer

The BETs on this website are a summary of the evidence found on a topic and are not clinical guidelines. It is the responsibility of the individual veterinary surgeon to ensure appropriate decisions are made based on the specific circumstances of patients under their care, taking into account other factors such as local licensing regulations. Read small print

References

Waelchli, RO, Thun, R, Stocker, H, (1999). Effect of flunixin meglumine on placental expulsion in dairy cattle after a caesarean.  Veterinary Record 144:702-703.

About this BET

First author:
Rachel Dean
Second author:
Marnie Brennan
Institution:

CEVM, University of Nottingham

Search last performed:
2017-07-20 15:14:32
Original publication date:
2017-07-31 15:14:32
Last updated:
2017-07-31 15:14:32
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