The evolving landscape of healthcare, marked by the persistent scarcity of intensive care unit (ICU) beds and mechanical ventilators, emphasizes the imperative of judicious resource allocation. 

Our study aims to find out the demographic and clinical factors intricately linked to postoperative mechanical ventilation following major abdominal cancer surgery. It will also help us make data-driven decisions to schedule major surgeries of patients who are likely to require postoperative mechanical ventilation given that a fixed number of ICU beds are available at a given point.  Few published articles [1,2,3,4] addressed this issue in adults and children undergoing cardiac surgery and liver transplantation surgery.  However the data for major abdominal cancer surgery patients are lacking [5,6]. 

At present we also have no data to make informed decisions regarding the expected length of ICU stay and hospital stay of patients who receive postoperative mechanical ventilation. This study shall also explore the association of other clinical factors of postoperative mechanical ventilation with the length of ICU stay and the hospital stay. 

The Department of Anesthesiology Critical Care & Pain at MPMMCC Varanasi maintains a clinical registry of all postoperative patients who are transferred to the Surgical ICU (SICU) from the OT directly after surgery, including those continue to require mechanical ventilation in the ICU after the end of surgery. 

This is a retrospective observational study of patients who underwent major abdominal cancer surgery and were shifted mechanically ventilated to the SICU.  This study will be based on 6-months-period data at MPMMCC Varanasi from the SICU registry. This study shall explore the demographic profile and clinical factors associated with the requirement of postoperative mechanical ventilation after major cancer surgery. 

Since ICU beds are a scarce resource in most health care settings. Judicial and equitable allocation of ICU beds and ventilators is an important factor to ensure optimum distribution of healthcare resources among patients and various surgical DMGs. This retrospective observational study at MPMMCC Varanasi seeks to elucidate the demographic factors and clinical determinants that underlie the necessity for postoperative mechanical ventilation in patients undergoing major cancer surgeries. Over a 6-month period, this study aims to contribute valuable insights for optimizing healthcare resource distribution. 

Aims/Objectives: 

Primary Objective: 

Characterise the demographic and perioperative clinical factors intricately linked to postoperative mechanical ventilation following major cancer surgery. 


Secondary Objectives: 

1. To observe the duration of ICU stay and length of hospital stay of patients who were shifted mechanically ventilated to ICU after major abdominal cancer surgery.

2. To observe for any postoperative complication till 30 days of completion of major abdominal cancer surgery

Design of the Study: 

A retrospective observational study, harnessing the wealth of information encapsulated in clinical registry data. 

Study Population: 

1. Inclusion Criteria: 

- Patients who were shifted mechanically ventilated from OT to the ICU after major abdominal cancer surgery.
- Patients of both sexes aged 18 years and above
2. Exclusion Criteria: 
- Patients who were shifted  intubated  but not mechanically ventilated from OT to ICU
- Patients whose data is unavailable or incomplete for that period
Study Methodology: 

1. Sampling Technique: 

Inclusive enrollment of the entire eligible population during the stipulated 6-month period  from 1^st July  2023 to 31^st December 2023.

2. Informed Consent: 

This is a retrospective observational study based only on historical clinical data from hospital registry. As there is no direct interaction with participants, the requirement for explicit informed consent is requested to be waived. 

3. Randomization/Intervention: 

Not applicable, given the observational nature of the study. 

4. Data Collection: 

We shall collect comprehensive clinical registry data encompassing demographics, cancer diagnosis, cancer surgery details, preoperative comorbidities, intraoperative anesthesia record, duration of surgery, and postoperative course details, length of ICU stay, overall hospital stay and postoperative complications. 

Power and Sample Size Estimates: 

Total enumerative sampling of the whole data of in the SICU clinical registry for the period – 1^st July 2023 to 31^st December 2023

Variables to be Measured: 

A). Patient’s demographic details: 

Participant ID in the study: 

Age: 

Gender: Male / Female 

Height (cm): 

Preoperative Weight (kg): 

ASA Physical Status: (Choose one) I / II / III / IV / V 

Coexisting illness - Hypertension: Yes / No , Diabetes Mellitus: Yes / No , Anemia: Yes / No , Pre-existing Kidney Dysfunction: Yes / No , Pre-existing Heart Failure: Yes / No , Pre-existing neurological disorders: Yes / No 

B). Surgery Details: 

Surgery Date: 

Type of Surgery: 

Anesthesia Procedure: 

Elective or Emergency Surgery: (Choose one) 

Duration of Surgery (in minutes): 

Intraoperative Blood Loss (in mL): 

Intraoperative Blood Transfusions: Yes / No 

Total Volume of Intraoperative Fluids (in mL): 

Type of IV Fluids: 

Intraoperative Urine Output (in mL): 

Body temperature (degree Celsius) at the end of surgery: 

 C . Course of ICU stay

Duration of mechanical ventilation after surgery:

Sedation: Yes / No
Duration of sedation:

Neuromuscular blocking agents used in ICU: No / Yes

Requirement of re-intubation after initial weaning and extubation:

Requirement of HFNC support after extubation

Length of ICU stay  -

D. Hospital Stay:

Total Length of Hospital Stay within 30 days post-surgery (including readmission stays):

Total Length of ICU Stay within 30 days post-surgery (including ICU readmission stays):

E). Outcome Measures: 

Documented complications will be classified according to Clavien-Dindo classification system of surgical complications

Analysis of the Variables: 

Descriptive statistics, univariate and multivariate analyses will be done to characterise the demographic and perioperative clinical factors intricately linked to postoperative mechanical ventilation following major cancer surgery. 

Adverse Events: 

Not applicable for observational studies. 

Possible Risks and Discomfort: 

No risk associated with data analysis; no direct participant intervention.
Benefits to Participants: 

Although participants won’t directly benefit, the indirect advantage lies in the optimized allocation of healthcare resources (OT and ICU services) translating into societal benefit. 

Benefit/Risk Assessment: 

No risk with potentially high societal benefits through enhanced resource optimization. 

Treatment of Complications: 

Not applicable for observational studies. 

Cost of Complications: 

Not applicable for observational studies. 

Informed Consent: 

Waiver of consent is requested due to the retrospective observational design, and no direct contact of the researchers with the patients. 

Additional Plans for Special Populations / Vulnerable population: 

Not applicable for this study. 

Confidentiality and Privacy: 

Data will be de-identified and stored securely in a locked cupboard of the Department and password protected and encrypted computer systems and cloud drives to ensure participant privacy. 

CTRI registration: Not mandatory. However, we shall register the study with CTRI after IEC approval, before starting data collection. 

Study Records: 

Study records will be maintained by the principal investigator at MPMMCC (Tata Memorial Centre) Varanasi for 5 years.

Data Storage: 

Data will be stored for 5 years in a secure, password-protected database at Department of Anesthesiology, Critical Care & Pain, MPMMCC (Tata Memorial Centre) Varanasi. 

Access to the study documents will be limited to PI co-PI and co-I only.
Post-Research Access to Participants: 

Not applicable, as no direct contact with participants is involved in this retrospective study.

References: 

1. Sahinturk H, Ozdemirkan A, Zeyneloglu P, Torgay A, Pirat A, Haberal M. Risk Factors for Postoperative Prolonged Mechanical Ventilation After Pediatric Liver Transplantation. Exp Clin Transplant. 2021 Sep;19(9):943-947. doi: 10.6002/ect.2018.0317. Epub 2019 May 14. PMID: 31084587. 

2. Gupta P, Rettiganti M, Gossett JM, Yeh JC, Jeffries HE, Rice TB, Wetzel RC. Risk factors for mechanical ventilation and reintubation after pediatric heart surgery. J Thorac Cardiovasc Surg. 2016 Feb;151(2):451-8.e3. doi: 10.1016/j.jtcvs.2015.09.080. Epub 2015 Sep 28. PMID: 26507405. 

3. Koutsogiannaki S, Huang SX, Lukovits K, Kim S, Bernier R, Odegard KC, Yuki K. The Characterization of Postoperative Mechanical Respiratory Requirement in Neonates and Infants Undergoing Cardiac Surgery on Cardiopulmonary Bypass in a Single Tertiary Institution. J Cardiothorac Vasc Anesth. 2022 Jan;36(1):215-221. doi: 10.1053/j.jvca.2021.04.023. Epub 2021 Apr 25. PMID: 34023203. 

4. Meng Y, Gu H, Qian X, Wu H, Liu Y, Ji P, Xu Y. Establishment of a nomogram for predicting prolonged mechanical ventilation in cardiovascular surgery patients. Eur J Cardiovasc Nurs. 2023 Sep 5;22(6):594-601. doi: 10.1093/eurjcn/zvac076. PMID: 36017648. 

5. LAS VEGAS investigators. Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications: LAS VEGAS - an observational study in 29 countries. Eur J Anaesthesiol. 2017 Aug;34(8):492-507. doi: 10.1097/EJA.0000000000000646. PMID: 28633157; PMCID: PMC5502122. 

6. Fernandez-Bustamante A, Frendl G, Sprung J, Kor DJ, Subramaniam B, Martinez Ruiz R, Lee JW, Henderson WG, Moss A, Mehdiratta N, Colwell MM, Bartels K, Kolodzie K, Giquel J, Vidal Melo MF. Postoperative Pulmonary Complications, Early Mortality, and Hospital Stay Following Noncardiothoracic Surgery: A Multicenter Study by the Perioperative Research Network Investigators. JAMA Surg. 2017 Feb 1;152(2):157-166. doi: 10.1001/jamasurg.2016.4065. PMID: 27829093; PMCID: PMC5334462.