Short-Term Survival and Postoperative Complications Rates in Horses Undergoing Colic Surgery: A Multicentre Study

Round 1

Reviewer 1 Report

Overall, this paper confirms what has previously been published in the literature on this subject. If the authors feel that further publication in the field is justified, further explanation should be provided as to why Italian horses would be any different than other populations of horses. Additionally, the conclusion regarding administration of crystalloids is very misleading to the reader, and likely seems to be correlative rather than causative.

 

General comment: Please review grammar and punctuation, per the journal’s guidelines as there are numerous errors throughout the current version of this manuscript.

 

Simple Summary

Line 13: Not all colic cases require surgical treatment, more intensive medical management may also be sufficient.

Lines 23-24: These comments about fluids are not helpful for the reader. Additionally, if the animal is well-hydrated then fluids may not be necessary. Additionally, IV vs enteral fluids is not specified, and should be balanced against the additional risks for administration.

 

Abstract

Lines 38-39: The comments about fluid administration are somewhat misleading, as often shock boluses are given in the amount of 40-60 ml/kg. Additionally, is selection bias a possibility, i.e., are horses with more severe lesions or in more critical condition being given larger fluid boluses? The causation/correlation relationship should be carefully addressed.

Line 42: Why are these outcomes only relevant to the Italian horse population? Why were they expected to be any different in the first place?

 

Introduction

Lines 48-49: Please clarify this statement. Are you referring the anesthetic-related deaths or underlying etiology for colic-related deaths?

Lines 56-58: There are numerous other publications looking at short-term outcomes in different types of colic.

Line 59: Please clarify why the Italian population of horses are believed to be different than other parts of the world. It is difficult to understand the impact of this paper without that information. This comment also applies to lines 68-69.

 

Materials & Methods

Line 78: Were there inclusion or exclusion criteria? Did records need to be complete or were incomplete records acceptable? Please expand the details here.

Line 97: If surgeon experience if of interest, this should be presented as captured information for the retrospective study.

 

Results

Line 114: Although general details can be helpful, it would likely be more helpful for the reader if horses and admission data were divided based on final diagnosis, since strangulating lesions will have markedly different clinical and hematologic admission data compared to non-strangulating lesion cases.

Line 131: Did all horses die related to colic? Were there catastrophic injuries or other medical complications? Please specify.

Lines 130-142: These data are likely better described in a table. These data may be integrated into Table 2, or the table modified to a figure/flow chart.

Lines 145-147: Data provided in a table should not be repeated in the text.

Lines 152-154: See previous comment.

Lines 161-164: Why do the percentages in the text not match the table?

General comment: The tables in the results are basic lists and could be reworked and integrated to provide more valuable information for the reader. Please also provide table legends.

Table 5: Why are some surgeons bolded? Presumably this has to do with their experience, but no table legends (for this table and others) are provided.

Lines 184-185: What is this time period?

Lines 215-216: Did these older horses have a higher proportion of a specific type of lesion?

Line 238: Please provide more clarification on this statement—was this across all hospitalization? Immediately pre-op? Is there a correlation to PCV (assumed)? Were crystalloids used in conjunction with hypertonic saline or other colloids?

 

Discussion

General comment: Overall, the Discussion feels to be strongly repeating what has been published elsewhere. It is difficult to see the “value added” to the reader from the current discussion.

Lines 322-323: The rate and volume of infusion is described in the veterinary literature and the human literature. These comments should be tempered/revised.

 

Conclusions

General comments: The authors should address why the Italian population of horses is expected to be different and the impact this study has on the body of clinical literature as it relates to equine colic.

 

Author Response

REVIEWER 1:

Simple Summary

R1.1 Line 13: Not all colic cases require surgical treatment, more intensive medical management may also be sufficient.

The reviewer is right. This is included in “medical treatment”

 

R1.2 Lines 23-24: These comments about fluids are not helpful for the reader. Additionally, if the animal is well-hydrated then fluids may not be necessary. Additionally, IV vs enteral fluids is not specified, and should be balanced against the additional risks for administration.

R1.2 the whole article has been reviewed according this comment and other comments. This issue has been completely rewritten. Abstract has been revised accordignly 

 

Abstract

R1.3 Lines 38-39: The comments about fluid administration are somewhat misleading, as often shock boluses are given in the amount of 40-60 ml/kg. Additionally, is selection bias a possibility, i.e., are horses with more severe lesions or in more critical condition being given larger fluid boluses? The causation/correlation relationship should be carefully addressed.

R1.3 the reviewer is right. The abstract has been revised

 

R1.4 Line 42: Why are these outcomes only relevant to the Italian horse population? Why were they expected to be any different in the first place?

R1.4

 Changed, see text

Introduction

R1.5 Lines 48-49: Please clarify this statement. Are you referring the anesthetic-related deaths or underlying etiology for colic-related deaths?

R1.5: changed, see text

 

 

R1.6 Lines 56-58: There are numerous other publications looking at short-term outcomes in different types of colic.

Changed, see text

 

R1.7 Line 59: Please clarify why the Italian population of horses are believed to be different than other parts of the world. It is difficult to understand the impact of this paper without that information. This comment also applies to lines 68-69.

R1.7 changed, see text

 

Materials & Methods

R1.8 Line 78: Were there inclusion or exclusion criteria? Did records need to be complete or were incomplete records acceptable? Please expand the details here.

Inserted, see text

 

R1.9 Line 97: If surgeon experience if of interest, this should be presented as captured information for the retrospective study. 

Inserted, see text

 

Results

R1.10 Line 114: Although general details can be helpful, it would likely be more helpful for the reader if horses and admission data were divided based on final diagnosis, since strangulating lesions will have markedly different clinical and hematologic admission data compared to non-strangulating lesion cases.

Inserted, see text

 

R1.11 Line 131: Did all horses die related to colic? Were there catastrophic injuries or other medical complications? Please specify.

This is specified at the end of paragraph

 

R1.12 Lines 130-142: These data are likely better described in a table. These data may be integrated into Table 2, or the table modified to a figure/flow chart.

A flow chart has been inserted

 

R1.13 Lines 145-147: Data provided in a table should not be repeated in the text.

Changed, see text

 

R1.14 Lines 152-154: See previous comment.

Changed, see text

 

R1.15 Lines 161-164: Why do the percentages in the text not match the table?

Sorry, data have been re-checked

 

R1.16 General comment: The tables in the results are basic lists and could be reworked and integrated to provide more valuable information for the reader. Please also provide table legends.

Changed, see table

 

Table 5: Why are some surgeons bolded? Presumably this has to do with their experience, but no table legends (for this table and others) are provided.

Changed, see table

 

R1.17 Lines 184-185: What is this time period?

The reviewer is right. We inserted this detail (within the same hospitalization period)

 

R1.18 Lines 215-216: Did these older horses have a higher proportion of a specific type of lesion?

Inserted in text

 

R1.19 Line 238: Please provide more clarification on this statement—was this across all hospitalization? Immediately pre-op? Is there a correlation to PCV (assumed)? Were crystalloids used in conjunction with hypertonic saline or other colloids?

Inserted, see  text

 

Discussion

R1.20 General comment: Overall, the Discussion feels to be strongly repeating what has been published elsewhere. It is difficult to see the “value added” to the reader from the current discussion.

R1.20 the whole introduction and discussion manuscript have been revised and multivariate analysis has been performed to add value to the manuscript

 

R1.21 Lines 322-323: The rate and volume of infusion is described in the veterinary literature and the human literature. These comments should be tempered/revised.

Changed, see text

 

Conclusions

R1.22 General comments: The authors should address why the Italian population of horses is expected to be different and the impact this study has on the body of clinical literature as it relates to equine colic.

R1.22 changed, see text

Author Response File: Author Response.docx

Reviewer 2 Report

some minor changes, see the following notes.

line 24: delete "."

page 6 first line substitute DPJ with "Duodenitis-proximal jeunitis (DPJ)"

page 6 line 16th: substitute POI with "Post operative ileus (POI)"

page 9, last line: substitute SIRS with "Systemic inflammatory response syndrome (SIRS)"

Author Response

REVIEWER 2:

R2.1 Line 11: still has

Changed, see text

R2.2 Line 19: 80% of the horses surviving surgery

Changed, see text

R2.3 Line 20: in line with previously published data

Changed, see text

R2.4 Line 21: intra and postoperatively

Changed, see text

R2.5 Line 21: the outcome. This

R2.6 Line 22: on the Italian equine population

Changed, see text

R2.7 Line 23 and 24: Pease check punctuation, spaces and capital characters

Changed, see text

R2.8 Line 33 and 34: Please adjust this sentence. Meaning is currently unclear

Changed,see text

 

 

R2.9 Line 36: 80% of the horses surviving surgery

Changed, see text

R2.10 Line 38: in line with previously published data

Changed, see text

R2.11 Line 42: on the Italian equine population

Changed, see text

R2.12 Line 48: still has

Changed, see text

R2.13 Line 53: have already been published

Changed, see text

R2.14 Line 54: short-term. Please be consistent

Changed, see text

R2.15 Line 57: please rephrase; this assumption is not really true since some of your references are from 2020 and 2022

Changed, see text

R2.16 Line 58 and 59: you could say that no such multicentric studies have been conducted in Italy

Changed, see text

R2.17 Line 62: has its own intrinsic and…

Changed, see text

R2.18 Line 66: Studies on predictive

Changed, see text

R2.19 Line 88: if horses survived to discharge or not.

Changed, see text

R2.20 Line 91: statistical software (JMP Pro 16, JMP Statistical Discovery LLC).

Changed, see text

R2.21 Line 93: of all horses underwent colic surgery

Changed, see text

R2.22 Line 94 and 95: Please adjust. Maybe say the differences between horses surviving and not surviving to discharge were…

Changed, see text

R2.23 Line 100 and 101: were used in parameters that were significant in the univariate analysis to evaluate discrimination…

Changed, see text

R2.24 Line 103: in the previous model OR in previous models

Changed, see text

R2.25 Lines 111-113: Maybe put only one number after the dot in your percentages to be consistent

Changed, see text

R2.26 Line 111: What is a hot blood horse? Thoroughbred?

Hot-blooded horses include thoroughbreds and arabians

R2.27 Line 112: Saddlebred

Changed, see text

R2.28 Line 114: Clinical features upon arrival

Changed, see text

R2.29 Line 116: between brackets

Changed, see text

R2.30 Line 120: Nasogastric reflux

Changed, see text

R2.31 Line 121: Please adjust. I don’t understand the 22.6% if you say that MOST of the horses were seen healthy during the previous 24 hours

The reviewer is right. N of horses was 91 out of 401 (22.7%) for which this data was available

R2.32 Line 122: to the hospital; when the animal was last seen healthy

changed, see text

R2.33 Table 1: It would be more logical to organize the table with increasing hours, not with increasing numbers

Changed, see text

R2.34 Line 130: we are missing 0.1%

Changed see text

R2.35 Line 131: in the recovery box

Changed, see text

R2.36 Line 132 and 133: you should explain what the difference is between owner’s decision and surgeon’s decision and adjust the term “not operable” because we actually DID operate on them

Changed, see text

R2.37 Line 136: of the small intestine; of the large intestine…

Changed, see text

R2.38 Line 138: please explain what are the 2 cases of other viscera

Inserted, see text

R2.39 Line 140: I doubt that endotoxemia was a surgical finding justifying euthanasia. Please rephrase

Changed, see text

R2.40 Line 141: did not recover from anesthesia

Changed, see text

R2.41 Lines 143-144: still missing 0.1%

Changed, see text

R2.42 Line 149, 156 and 166: that underwent colic surgery

Changed, see text

R2.43 Table 2: why is the pelvic flexure separated from the large colon??

Sorry, this was a mistake. Pelvic flexure has been included with large colon

R2.44 Table 3: please develop DPJ; why did you separate small intestine obstruction, ileal impaction and jejunal impaction? Was the abdominal hernia the cause of the colic requiring a laparotomy? What is a duodenal entrapment? Rectal prolapse. Why did you separate mesenteric abscess, abscess and hepatic abscess? Why did you separate small intestinal neoplasia, lymphoma and focal eosinophilic enteritis?

 

R2.45 Line 161: resection and anastomosis were performed

Changed, see text

R2.46 Table 4: Hybrid; I would say jejuno-jejunal rather that jejuno-jejunostomy to be consistent

Changed, see text

R2.47 Line 170: add “hours”; how can it be 0 for the lowest part of the range?? I takes at least a few minutes to open up an equine abdomen

Inserted and corrected, see text

R2.48 Table 5: in the third column you should maybe say “Number of colic surgeries per year”

Changed, see text

R2.49 Line 180: please define delta PCV and delta TPP

Inserted, see text

R2.50 Line 192: please define pyrexia: 38,6°C?

Inserted, see text

R2.51 Line 193: please rephrase, not clear           

Changed, see text

R2.52 Line 194: please define SSI: drainage? Purulent? Sanguineous?

Inserted, see text

R2.53 Line 195: Please define clinical signs of piroplasmosis

Inserted, see text

R2.54 Table 6: your percentage of pyrexia is different between the text and the table; same problem for piroplasmosis, colic, reflux… Why did you separate piroplasmosis and clinical signs of piroplasmosis? What are the other complications?

Changed, see text

R2.55 Line 205: that underwent colic surgery

Changed, see text

R2.56 Line 206: 386 horses that survived surgery

Changed, see text

R2.57 Line 207: that underwent euthanasia

Changed, see text

R2.58 Lines 208-210: please rephrase

Changed, see text

R2.59 Lines 212-213 should belong to the discussion

Changed, see text

R2.60 Line 215: Horses aged >14 years were 2.3 times more likely…

Changed, see text

R2.61 Line 218: please rephase “The cut-off to define the risk BCS value is 7”

Changed, see text

R2.62 Line 222: had a poorer prognosis

Changed, see text

R2.63 Line 226: associated with a higher

Changed, see text

R2.64 Line 231: resection and anastomosis

Changed, see text

R2.65 Line 232: higher than in horses that underwent intestinal

Changed, see text

R2.66 Line 233: The type of anastomosis did not have a significant effect on the outcome.

Changed, see text

R2.67 Line 235: numbers of horses operated per year? Please rephrase

Changed, see text

R2.68 Line 238: associated with a poorer prognosis

Changed, see text

R2.69 Line 239: please remove “in conclusion”

Changed, see text

R2.70 Line 242: how long do you need for your delta PCV? How many hours after surgery?

Described above, see text

R2.71 Line 244: is it really a loss < or > to 2.2g/dL?

The reviewer is right. Changed, see text

R2.72 Line 260: horses that underwent OR horses undergoing

Changed, see text

R2.73 Line 271: Freeman 2018 should have a reference number

Changed, see text

R2.74 Lines 271-272: What is the difference between a favourable prognosis and a positive short-term outcome. Please clarify

Changed, see text

R2.75 Lines 274-275: “which is why they may have less impact on the short-term survival rate” this sentence is unclear. Please clarify

Removed, see text

R2.76 Line 279 and 280: of the small intestine

Changed, see text

R2.77 Line 282: horses that did not have an anastomosis performed

Changed, see text

R2.78 Line 284: because it could cause…Well, in this sentence it must be clarified that a necrotic piece of bowel has to be resected in all cases and that in other cases, if the strangulated piece of bowel is deemed viable it can be left in place. Please refer to Freeman et al., EVJ 2014. In this paper different grades are defined to assess viability of the strangulated small intestine. Same thing for line 289-293

This paragraph has been removed

R2.79 Line 294: The type of anastomosis was not found to affect the outcome

Changed, see text

R2.80 Lines 304-305: “Prospective studies comparing different types of anastomoses for the same pathology could give more indications in this regard”. As you mention in line 298, the type of anastomosis depends on the actual pathology and most of the time you don’t really have the choice about the anastomosis that has to be done. Some papers have compared the jejunoileal anastomosis and the jejunocecal anastomosis, maybe you could discuss/add this. Please adjust this part.

Changed, see text.

R2.81 Line 309: could influence the development; during recovery

Changed, see text

R2.82 Line 311-313: your statistical analysis should tell you if surgical time is a confounding factor or really a risk factors for complications to happen

Changed, see text

R2.83 Lines 320-338: As explained previously, this part must be balanced or adjusted. Sick horses, such as those with a LCV or a small intestinal resection and anastomosis, are likely in need of more fluids than horses with a simple large colon displacement. These sick horses are also less likely to survive from their compromised status. To me it is an overstatement to say that “overhydration” is a negative factor from survival.

 

R2.83. this part has been adjusted

R2.84 A multivariate analysis could greatly improve the conclusions of your study.

It has been included in the manuscript

Author Response File: Author Response.docx

Reviewer 3 Report

Overall, the conclusion that excessive fluid therapy worsens the prognosis seems unsuitable. It is much more likely that critically sick horses would require more fluids, a longer hospitalization period and would be more likely to die.

 

Line 11: still has

Line 19: 80% of the horses surviving surgery

Line 20: in line with previously published data

Line 21: intra and postoperatively

Line 21: the outcome. This

Line 22: on the Italian equine population

Line 23 and 24: Pease check punctuation, spaces and capital characters

Line 33 and 34: Please adjust this sentence. Meaning is currently unclear

Line 36: 80% of the horses surviving surgery

Line 38: in line with previously published data

Line 42: on the Italian equine population

Line 48: still has

Line 53: have already been published

Line 54: short-term. Please be consistent

Line 57: please rephrase; this assumption is not really true since some of your references are from 2020 and 2022

Line 58 and 59: you could say that no such multicentric studies have been conducted in Italy

Line 62: has its own intrinsic and…

Line 66: Studies on predictive

Line 88: if horses survived to discharge or not.

Line 91: statistical software (JMP Pro 16, JMP Statistical Discovery LLC).

Line 93: of all horses underwent colic surgery

Line 94 and 95: Please adjust. Maybe say the differences between horses surviving and not surviving to discharge were…

Line 100 and 101: were used in parameters that were significant in the univariate analysis to evaluate discrimination…

Line 103: in the previous model OR in previous models

Lines 111-113: Maybe put only one number after the dot in your percentages to be consistent

Line 111: What is a hot blood horse? Thoroughbred?

Line 112: Saddlebred

Line 114: Clinical features upon arrival

Line 116: between brackets

Line 120: Nasogastric reflux

Line 121: Please adjust. I don’t understand the 22.6% if you say that MOST of the horses were seen healthy during the previous 24 hours

Line 122: to the hospital; when the animal was last seen healthy

Table 1: It would be more logical to organize the table with increasing hours, not with increasing numbers

Line 130: we are missing 0.1%

Line 131: in the recovery box

Line 132 and 133: you should explain what the difference is between owner’s decision and surgeon’s decision and adjust the term “not operable” because we actually DID operate on them

Line 136: of the small intestine; of the large intestine…

Line 138: please explain what are the 2 cases of other viscera

Line 140: I doubt that endotoxemia was a surgical finding justifying euthanasia. Please rephrase

Line 141: did not recover from anesthesia

Lines 143-144: still missing 0.1%

Line 149, 156 and 166: that underwent colic surgery

Table 2: why is the pelvic flexure separated from the large colon??

Table 3: please develop DPJ; why did you separate small intestine obstruction, ileal impaction and jejunal impaction? Was the abdominal hernia the cause of the colic requiring a laparotomy? What is a duodenal entrapment? Rectal prolapse. Why did you separate mesenteric abscess, abscess and hepatic abscess? Why did you separate small intestinal neoplasia, lymphoma and focal eosinophilic enteritis?

Line 161: resection and anastomosis were performed

Table 4: Hybrid; I would say jejuno-jejunal rather that jejuno-jejunostomy to be consistent

Line 170: add “hours”; how can it be 0 for the lowest part of the range?? I takes at least a few minutes to open up an equine abdomen

Table 5: in the third column you should maybe say “Number of colic surgeries per year”

Line 180: please define delta PCV and delta TPP

Line 192: please define pyrexia: 38,6°C?

Line 193: please rephrase, not clear

Line 194: please define SSI: drainage? Purulent? Sanguineous?

Line 195: Please define clinical signs of piroplasmosis

Table 6: your percentage of pyrexia is different between the text and the table; same problem for piroplasmosis, colic, reflux… Why did you separate piroplasmosis and clinical signs of piroplasmosis? What are the other complications?

Line 205: that underwent colic surgery

Line 206: 386 horses that survived surgery

Line 207: that underwent euthanasia

Lines 208-210: please rephrase

Lines 212-213 should belong to the discussion

Line 215: Horses aged >14 years were 2.3 times more likely…

Line 218: please rephase “The cut-off to define the risk BCS value is 7”

Line 222: had a poorer prognosis

Line 226: associated with a higher

Line 231: resection and anastomosis

Line 232: higher than in horses that underwent intestinal

Line 233: The type of anastomosis did not have a significant effect on the outcome.

Line 235: numbers of horses operated per year? Please rephrase

Line 238: associated with a poorer prognosis

Line 239: please remove “in conclusion”

Line 242: how long do you need for your delta PCV? How many hours after surgery?

Line 244: is it really a loss < or > to 2.2g/dL?

Line 260: horses that underwent OR horses undergoing

Line 271: Freeman 2018 should have a reference number

Lines 271-272: What is the difference between a favourable prognosis and a positive short-term outcome. Please clarify

Lines 274-275: “which is why they may have less impact on the short-term survival rate” this sentence is unclear. Please clarify

Line 279 and 280: of the small intestine

Line 282: horses that did not have an anastomosis performed

Line 284: because it could cause…

Well, in this sentence it must be clarified that a necrotic piece of bowel has to be resected in all cases and that in other cases, if the strangulated piece of bowel is deemed viable it can be left in place. Please refer to Freeman et al., EVJ 2014. In this paper different grades are defined to assess viability of the strangulated small intestine. Same thing for line 289-293

Line 294: The type of anastomosis was not found to affect the outcome

Lines 304-305: “Prospective studies comparing different types of anastomoses for the same pathology could give more indications in this regard”. As you mention in line 298, the type of anastomosis depends on the actual pathology and most of the time you don’t really have the choice about the anastomosis that has to be done. Some papers have compared the jejunoileal anastomosis and the jejunocecal anastomosis, maybe you could discuss/add this. Please adjust this part.

Line 309: could influence the development; during recovery

Line 311-313: your statistical analysis should tell you if surgical time is a confounding factor or really a risk factors for complications to happen

Lines 320-338: As explained previously, this part must be balanced or adjusted. Sick horses, such as those with a LCV or a small intestinal resection and anastomosis, are likely in need of more fluids than horses with a simple large colon displacement. These sick horses are also less likely to survive from their compromised status. To me it is an overstatement to say that “overhydration” is a negative factor from survival.

A multivariate analysis could greatly improve the conclusions of your study.

Author Response

REVIEWER 3:

R3.1 Line 11: still has

Changed, see text

R3.2 Line 19: 80% of the horses surviving surgery

Changed, see text

R3.3 Line 20: in line with previously published data

Changed, see text

R3.4 Line 21: intra and postoperatively

Changed, see text

R3.5 Line 21: the outcome. This

R3.6 Line 22: on the Italian equine population

Changed, see text

R3.7 Line 23 and 24: Pease check punctuation, spaces and capital characters

Changed, see text

R3.8 Line 33 and 34: Please adjust this sentence. Meaning is currently unclear

Changed,see text

 

 

R3.9 Line 36: 80% of the horses surviving surgery

Changed, see text

R3.10 Line 38: in line with previously published data

Changed, see text

R3.11 Line 42: on the Italian equine population

Changed, see text

R3.12 Line 48: still has

Changed, see text

R3.13 Line 53: have already been published

Changed, see text

R3.14 Line 54: short-term. Please be consistent

Changed, see text

R3.15 Line 57: please rephrase; this assumption is not really true since some of your references are from 2020 and 2022

Changed, see text

R3.16 Line 58 and 59: you could say that no such multicentric studies have been conducted in Italy

Changed, see text

R3.17 Line 62: has its own intrinsic and…

Changed, see text

R3.18 Line 66: Studies on predictive

Changed, see text

R3.19 Line 88: if horses survived to discharge or not.

Changed, see text

R3.20 Line 91: statistical software (JMP Pro 16, JMP Statistical Discovery LLC).

Changed, see text

R3.21 Line 93: of all horses underwent colic surgery

Changed, see text

R3.22 Line 94 and 95: Please adjust. Maybe say the differences between horses surviving and not surviving to discharge were…

Changed, see text

R3.23 Line 100 and 101: were used in parameters that were significant in the univariate analysis to evaluate discrimination…

Changed, see text

R3.24 Line 103: in the previous model OR in previous models

Changed, see text

R3.25 Lines 111-113: Maybe put only one number after the dot in your percentages to be consistent

Changed, see text

R3.26 Line 111: What is a hot blood horse? Thoroughbred?

Hot-blooded horses include thoroughbreds and arabians

R3.27 Line 112: Saddlebred

Changed, see text

R3.28 Line 114: Clinical features upon arrival

Changed, see text

R3.29 Line 116: between brackets

Changed, see text

R3.30 Line 120: Nasogastric reflux

Changed, see text

R3.31 Line 121: Please adjust. I don’t understand the 22.6% if you say that MOST of the horses were seen healthy during the previous 24 hours

The reviewer is right. N of horses was 91 out of 401 (22.7%) for which this data was available

R3.32 Line 122: to the hospital; when the animal was last seen healthy

changed, see text

R3.33 Table 1: It would be more logical to organize the table with increasing hours, not with increasing numbers

Changed, see text

R3.34 Line 130: we are missing 0.1%

Changed see text

R3.35 Line 131: in the recovery box

Changed, see text

R3.36 Line 132 and 133: you should explain what the difference is between owner’s decision and surgeon’s decision and adjust the term “not operable” because we actually DID operate on them

Changed, see text

R3.37 Line 136: of the small intestine; of the large intestine…

Changed, see text

R3.38 Line 138: please explain what are the 2 cases of other viscera

Inserted, see text

R3.39 Line 140: I doubt that endotoxemia was a surgical finding justifying euthanasia. Please rephrase

Changed, see text

R3.40 Line 141: did not recover from anesthesia

Changed, see text

R3.41 Lines 143-144: still missing 0.1%

Changed, see text

R3.42 Line 149, 156 and 166: that underwent colic surgery

Changed, see text

R3.43 Table 2: why is the pelvic flexure separated from the large colon??

Sorry, this was a mistake. Pelvic flexure has been included with large colon

R3.44 Table 3: please develop DPJ; why did you separate small intestine obstruction, ileal impaction and jejunal impaction? Was the abdominal hernia the cause of the colic requiring a laparotomy? What is a duodenal entrapment? Rectal prolapse. Why did you separate mesenteric abscess, abscess and hepatic abscess? Why did you separate small intestinal neoplasia, lymphoma and focal eosinophilic enteritis?

 

R3.45 Line 161: resection and anastomosis were performed

Changed, see text

R3.46 Table 4: Hybrid; I would say jejuno-jejunal rather that jejuno-jejunostomy to be consistent

Changed, see text

R3.47 Line 170: add “hours”; how can it be 0 for the lowest part of the range?? I takes at least a few minutes to open up an equine abdomen

Inserted and corrected, see text

R3.48 Table 5: in the third column you should maybe say “Number of colic surgeries per year”

Changed, see text

R3.49 Line 180: please define delta PCV and delta TPP

Inserted, see text

R3.50 Line 192: please define pyrexia: 38,6°C?

Inserted, see text

R3.51 Line 193: please rephrase, not clear           

Changed, see text

R3.52 Line 194: please define SSI: drainage? Purulent? Sanguineous?

Inserted, see text

R3.53 Line 195: Please define clinical signs of piroplasmosis

Inserted, see text

R3.54 Table 6: your percentage of pyrexia is different between the text and the table; same problem for piroplasmosis, colic, reflux… Why did you separate piroplasmosis and clinical signs of piroplasmosis? What are the other complications?

Changed, see text

R3.55 Line 205: that underwent colic surgery

Changed, see text

R3.56 Line 206: 386 horses that survived surgery

Changed, see text

R3.57 Line 207: that underwent euthanasia

Changed, see text

R3.58 Lines 208-210: please rephrase

Changed, see text

R3.59 Lines 212-213 should belong to the discussion

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R3.60 Line 215: Horses aged >14 years were 2.3 times more likely…

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R3.61 Line 218: please rephase “The cut-off to define the risk BCS value is 7”

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R3.62 Line 222: had a poorer prognosis

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R3.63 Line 226: associated with a higher

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R3.64 Line 231: resection and anastomosis

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R3.65 Line 232: higher than in horses that underwent intestinal

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R3.66 Line 233: The type of anastomosis did not have a significant effect on the outcome.

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R3.67 Line 235: numbers of horses operated per year? Please rephrase

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R3.68 Line 238: associated with a poorer prognosis

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R3.69 Line 239: please remove “in conclusion”

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R3.70 Line 242: how long do you need for your delta PCV? How many hours after surgery?

Described above, see text

R3.71 Line 244: is it really a loss < or > to 2.2g/dL?

The reviewer is right. Changed, see text

R3.72 Line 260: horses that underwent OR horses undergoing

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R3.73 Line 271: Freeman 2018 should have a reference number

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R3.74 Lines 271-272: What is the difference between a favourable prognosis and a positive short-term outcome. Please clarify

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R3.75 Lines 274-275: “which is why they may have less impact on the short-term survival rate” this sentence is unclear. Please clarify

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R3.76 Line 279 and 280: of the small intestine

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R3.77 Line 282: horses that did not have an anastomosis performed

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R3.78 Line 284: because it could cause…Well, in this sentence it must be clarified that a necrotic piece of bowel has to be resected in all cases and that in other cases, if the strangulated piece of bowel is deemed viable it can be left in place. Please refer to Freeman et al., EVJ 2014. In this paper different grades are defined to assess viability of the strangulated small intestine. Same thing for line 289-293

This paragraph has been removed

R3.79 Line 294: The type of anastomosis was not found to affect the outcome

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R3.80 Lines 304-305: “Prospective studies comparing different types of anastomoses for the same pathology could give more indications in this regard”. As you mention in line 298, the type of anastomosis depends on the actual pathology and most of the time you don’t really have the choice about the anastomosis that has to be done. Some papers have compared the jejunoileal anastomosis and the jejunocecal anastomosis, maybe you could discuss/add this. Please adjust this part.

Changed, see text.

R3.81 Line 309: could influence the development; during recovery

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R3.82 Line 311-313: your statistical analysis should tell you if surgical time is a confounding factor or really a risk factors for complications to happen

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R3.83 Lines 320-338: As explained previously, this part must be balanced or adjusted. Sick horses, such as those with a LCV or a small intestinal resection and anastomosis, are likely in need of more fluids than horses with a simple large colon displacement. These sick horses are also less likely to survive from their compromised status. To me it is an overstatement to say that “overhydration” is a negative factor from survival.

 

R3.83. this part has been adjusted

R3.84 A multivariate analysis could greatly improve the conclusions of your study.

It has been included in the manuscript

Author Response File: Author Response.docx

Reviewer 4 Report

Table 1 : would make more sense to call it : duration of symptoms.

Please adjust the time list in the table in a more logical manner. 

Please be consistent throughout the manuscript with the number expressed as numeric and not as spelled in words.

Section on reasons for euthanasia starting in line 133 can be deleted.

I would suggest the result section to consist of less text description and more tables. 

In your statistics I am missing torsion of the large colon- but in the section line 159 you refer to strangulating lesions. If you had both types of volvolus of the large colon in your case load, you need to separate them into non-strangulating volvolus of the large colon and large colon torsion, sometimes also referred to as volvolus and indicate the percentages of these also separatly in the tables.

Please always spell out abbreviations in the table legend.

 

Table 5 is incomprehensible and formatting cuts out part of the writing.

 

For all parameters listed in the result section it is not clear whether the authors are refering to the whole number of horses or only to those who survived surgery (which should be the case, since the former would not make sense).

 

Discussion is very vague and not actually discussing the results. From line the discussion diverges on whether it is an option to perform small intestinal resection or not in general.

 

 

Author Response

REVIEWER 4:

R4.1 Table 1 : would make more sense to call it : duration of symptoms.

Changed, see text

R4.2Please adjust the time list in the table in a more logical manner. 

Changed, see text

R4.3 Please be consistent throughout the manuscript with the number expressed as numeric and not as spelled in words.

Changed, see text

R4.4 Section on reasons for euthanasia starting in line 133 can be deleted.

Changed, see text

R4.5 I would suggest the result section to consist of less text description and more tables. 

Changed, see text

R4.6 In your statistics I am missing torsion of the large colon- but in the section line 159 you refer to strangulating lesions. If you had both types of volvolus of the large colon in your case load, you need to separate them into non-strangulating volvolus of the large colon and large colon torsion, sometimes also referred to as volvolus and indicate the percentages of these also separatly in the tables.

R4.6 a paragraph on strangulating/nonstrangulating lesions has been added in the results

R4.7 Please always spell out abbreviations in the table legend.

Changed, see text

 

R4.8 Table 5 is incomprehensible and formatting cuts out part of the writing.

Changed, see text

 

R4.9 For all parameters listed in the result section it is not clear whether the authors are refering to the whole number of horses or only to those who survived surgery (which should be the case, since the former would not make sense).

Changed. Number of horses has been specified

 

R4.10 Discussion is very vague and not actually discussing the results. From line the discussion diverges on whether it is an option to perform small intestinal resection or not in general.

The whole discussion has been revised

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Manuscript has been appropriately edited. 

Author Response

Dear Editor,

We would like to thank the editor and reviewers, we accepted all recommended revisions. 

Please see the attachment

Author Response File: Author Response.docx