Review for 10.1186/s12876-025-03827-w (2025)

Title: A nomogram to predict pulmonary complications after gastrointestinal surgery: a
retrospective study
Version: 3 Date: 15 Mar 2025
Reviewer:  Anwar Ashraf Abouelnasr
Reviewer's report:
Dear Authors, please address the following points below
-The retrospective design, while common in clinical research, has inherent limitations, such as
potential biases in data collection, missing data, and the inability to establish causal relationships.
A prospective study would strengthen the findings and minimize bias.
-The introduction mentions that prior studies on PPC risk factors after gastrointestinal surgery
have yielded inconsistent and controversial results. While this is acknowledged, the study does
not provide a detailed explanation of why these inconsistencies exist or how the current study
addresses these gaps. A deeper comparison with existing literature could offer better insight into
how this study’s findings differ or build upon previous work.
-The exclusion criteria are quite strict, specifically excluding patients with a history of abdominal
surgery or serious preoperative medical conditions. This may limit the generalizability of the
findings to the broader population, as these patients may be at a higher risk for PPC.
-Although the study mentions that statistical analyses were performed using SPSS and R
software, there is limited information on how missing data were handled, whether any
imputation techniques were used, or whether sensitivity analyses were conducted. These details
are important for assessing the robustness of the study's findings.
-While the nomogram is a promising tool, the study does not offer clear examples or case studies
to demonstrate how it would be used in a real clinical setting. Further information on how
healthcare providers can integrate the nomogram into routine practice would be beneficial.
-While a range of postoperative interventions are mentioned (ICU stay, tracheal intubation, etc.),
there is no clear explanation of how these interventions interact with PPC outcomes. A more
detailed analysis of the impact of specific interventions on the risk of developing PPC would
strengthen the conclusions drawn from the model.
-While the study discusses the associations between risk factors like hypertension, respiratory
disease, and low albumin with PPC, it would benefit from more detailed mechanistic
explanations of why these factors increase the risk of complications. For example, a deeper
exploration of how hypertension affects pulmonary ventilation or how respiratory diseases
impair lung function would add depth to the discussion.
-The study includes several postoperative factors, such as ICU time, PaO2, and tracheal
intubation time, as risk factors. While these factors are important, the study could give more
attention to preoperative optimization (e.g., managing hypertension or improving nutritional
status) to prevent PPC. There is also room to explore preoperative interventions that might
reduce the incidence of PPC, which could offer more proactive approaches.
-The discussion doesn’t delve much into how specific surgical techniques or variations might
contribute to PPC. Since gastrointestinal surgery encompasses various types (e.g., gastrectomy,
and colorectal surgery), a deeper dive into how different procedures might carry distinct risks
for pulmonary complications could be valuable.
-The term "excessive intraoperative bleeding" is used as a risk factor for PPC, but the definition
of “excessive” is not clear. Blood loss may be relative, and the discussion would benefit from
clarification or a more specific threshold for what constitutes excessive bleeding, as this could
impact the clinical applicability of the model.