INTRODUCTION

Biliary obstruction secondary to tumor infiltration or compression of the biliary tree is a frequent cause of obstructive jaundice. The most common causes of biliary obstruction are hepato-pancreatico-biliary (HPB) malignancies and rarely, lymphoma, and compressive metastatic lymph nodes. Obstructive jaundice precludes the use of chemotherapy, both in neoadjuvant and palliative settings. Biliary drainage, therefore, is one of the cornerstones in the management of patients with obstructive jaundice.

       Preoperative biliary drainage increases complications compared with surgery without preoperative drainage.  Nevertheless, some patients may benefit from preoperative relief of jaundice; these include patients with untreatable pruritus, acute cholangitis, very high bilirubin or renal dysfunction as a consequence of obstructive jaundice. In addition, patients in whom the surgical procedure is delayed due to neoadjuvant therapy or need of nutritional support in cases of high risk of malnourishment, or due to logistic issues, also require a preoperative biliary stenting.

In unresectable pancreatobiliary malignancies, biliary tree obstruction and consequent jaundice occur in 70–90% of patients and have important consequences mainly for the patient’s quality of life, morbidity, and overall mortality. Endoscopic stenting may be an option for palliative therapy of biliary tree obstruction others being surgical bypass and percutaneous external drainage/stenting.

Endoscopic retrograde cholangiopancreatography (ERCP) is the gold standard in the palliation of obstructive jaundice. With the wide use of ERCP, many critical patients in whom conventional surgery was a high-risk procedure could be managed by endoscopic treatment. The endoscopic transpapillary approach is generally preferred for biliary drainage in this preoperative setting. It can be associated with post procedure complications like pancreatitis, cholangitis, or hemorrhage.  The European Society of Gastrointestinal Endoscopy’s (ESGE) guidelines recommend placing a plastic stent for biliary drainage if a diagnosis of the biliary obstruction (malignant versus benign) is still not ascertained. For preoperative biliary drainage, the use of self-expandable metal stents (SEMS) should be preferred over plastic stents since they are associated with significantly lower complication rate and stent dysfunction, with a similar surgical complication rate.

Because of patient’s clinical status and technical difficulties posted for endoscopic procedures for drainage of pancreatobiliary obstruction, the choice of the anaesthetic technique presents a real challenge. These procedures, when compared to open surgical procedures are significantly less painful and despite being performed in prone/semi-prone position, may not need paralysis or endotracheal intubation. Patients planned for ERCP often have additional comorbidities that make them high-risk candidates for anesthesia therefore optimization of these patients is necessary. Many techniques have been proposed to relieve patient anxiety and discomfort and can vary from patient to patient, but mostly it is performed under sedation. The choices and techniques of anaesthesia and drug selection vary according to the condition of the patients, familiarity of the anaesthesiologists and the demand of the endoscopists. However, it carries some risks, and the use of general anesthesia may be necessary in some patients. Theoretically, unlike other procedures done under sedation or general anesthesia, carbon dioxide insufflation of the stomach and intestines during these procedures in prone position can predispose to higher risk of aspiration and vagally mediated hypotension. Previous literature on monitored anesthesia care under sedation advocates the use of endotracheal intubation with general anesthesia in high risk (higher American Society of Anesthesiologists (ASA) grade and obese patients.

         The outcomes of these procedures can vary from being totally uneventful to a stormy periprocedure course. There is a paucity of literature about anaesthesia practices and identification of risk factors affecting outcomes in endoscopic biliary drainage procedures. 

Therefore, we decided to conduct this audit to evaluate the anaesthesia practices during endoscopic procedures to relieve pancreatobiliary obstruction at our tertiary institute and to identify risk factors affecting the outcomes.

AIMS AND OBJECTIVES

The aim of this prospective audit is to evaluate the choices and techniques, drug usage during anaesthesia and complications which occur during the perioperative period of endoscopic procedures to relieve pancreatobiliary obstruction and to identify risk factors affecting the short term outcomes.

Primary outcome

To audit anaesthesia practices in  procedures for pancreatobiliary obstruction with respect to choices and techniques, drug usage and complications which occur  during the immediate perioperative period (till discharge from ICU)

Secondary outcome 

·         Mortality, complications after the procedure, length of hospital stay, and ICU admissions in patients undergoing endoscopic procedures to relieve pancreatobiliary obstruction will be recorded maximum uptill 30 days.

·         To identify risk factors affecting outcomes in endoscopic procedures for pancreatobiliary obstruction.

STUDY PERIOD:

The duration of study will be twelve months after obtaining IEC approval. Patients undergoing endoscopic procedures to drain pancreatobiliary obstruction in the twelve months after approval will be followed up for maximum up to 30 days of their length of hospital stay.  We will be assessing for the perioperative complications during and after the procedure. For the perioperative complications, we will follow them everyday till the patients are admitted with us. After discharge, they will be followed up on 30^th postoperative day telephonically.

VARIABLES TO BE RECORDED:

The anaesthesia practices will be studied pertaining to choices and techniques, drug usage and complications which occur during the intraoperative period. 

The mortality, complications after the procedure, length of hospital stay, and ICU admissions will be recorded maximum till 30 days of the procedure.

METHODS:

Ethics 

The prospective chart review will be undertaken after obtaining approval from the Institutional Ethics Committee (IEC).

Patients 

The study will include patients at our institute posted for elective and emergency endoscopic procedures for pancreatobiliary drainage. The study will be conducted in the Department of Anaesthesia,Critical Care and Pain at Tata Memorial Cancer Centre

INCLUSION CRITERIA 

All patients above 18 years undergoing elective and emergency endoscopic procedures for drainage of pancreatobiliary obstruction

EXCLUSION CRITERIA

 Patients below 18 years               

DETAILS OF STUDY PROCEDURES INVOLVED

Data will be collected from the electronic medical record system (EMR) of the hospital which contains patient’s clinical, laboratory and radiological data. Data will also be recorded from the patient’s case file, the anaesthesia and PACU (intraoperative and postoperative) management summaries, monitoring charts and will be entered in a prospectively maintained database. There will be no change in routine anaesthesia practice and care. No additional interventions will be performed. No additional hospital visits will be required.  The patients will be followed up maximum for 30 days. We will be assessing for the perioperative complications during and after the procedure. For the perioperative complications, we will follow them everyday till the patients are admitted with us. After discharge, they will be followed up on 30^thpostoperative day telephonically. Patient demographics, preoperative variables, intraoperative variables, and post operative clinical outcomes will be reviewed. 

Demographics 

·         Age

·         Sex

·         ASA physical status

·         Body Mass Index(BMI) & Obesity (BMI>30Kg/m2)

·         H/O Obstructive Sleep Apnea(using/not using CPAP)

·         H/o  smoking or tobacco use or alcohol use

·         Prior Neo Adjuvant Chemotherapy and  Prior Radiotherapy 

·         >10% loss in body weight in last 6 months

·         H/o previous stenting (prior ERCP/ PTBD/redo procedure) 

·         Previous surgery

·         H/o  sepsis and septic shock

·         Preoperative use of vasopressors

·         Time to endoscopy from presentation of symptoms

·         H/o use of antiplatelet drugs or Non Steroidal Anti Inflammatory Drugs

·         H/o use of Anticoagulant drugs

Comorbid conditions 

·         Cardiac conditions- Past h/o  hypertension, angina, myocardial infarction, previous percutaneous coronary intervention, or cardiac surgery, congestive heart failure, arrhythmias, on pacemaker.

·          Diabetes mellitus

·          Peripheral Vascular disease

·          Fraility score by Modified Fraility Index (mFi)-cutoff of 0.27 to distinguish between frail and non frail patients.

·          Haematological disease or bleeding disorder

·          Respiratory conditions- H/o dyspnea on exertion and rest, History of Chronic Obstructive Pulmonary Disease (COPD), asthma, pneumonia.

·         CNS Disease- H/o Transient Ischemic Attack,seizures, CVA  with or without  neurologic deficit

·         History of Renal disease- H/o Acute Kidney Injury  in the past/ Chronic Kidney Disease/patient on dialysis                  

·         H/o  jaundice or  liver  disease or cirrhosis

·         H/o  thyroid disease

·         H/o electrolyte disorders

·         H/o  pancreatitis in the past

·         H/o metastatic cancer.

Preoperative Investigations 

·         Complete Blood Count (haemoglobin,Whole Blood Count, platelet count)

·         Complete Coagulation profile

·         Preoperative LFT (S Albumin levels, S bilirubin(before drainage), Aspartate Aminotransferase, Alanine Aminotransferase

·         Renal Function Tests(Blood urea nitrogen and Serum Creatinine)

·         Serum electrolytes

·          Child Pugh Score (A,B,C)

·         Any other relevant investigations

Intraoperative Details-

 Indication  and Type  of  Procedure

·         Inpatient/ outpatient / shifted from ICU

·          Elective/ emergency

·         Preoperative stable/unstable hemodynamics

·          Preoperative Vitals(P/BP/RR/SAO2/etco2)

·         Monitoring

·         Preoperative antibiotics

·         Maintenance IV Fluids

·         Difficult airway- Mallampati  Grade or other significant predictors of difficult airway                              

·         Duration of anaesthesia

·          Duration of procedure

·          Anaesthesia by - trainee or consultant supervised

·          Procedure done by – trainee/consultant supervised/consultant

Type of Anaesthesia-

Airway management details

·         Anaesthesia  technique  and details

          Sedation – (drugs used/devices to maintain airway/supplemental oxygen while giving sedation)

               - deep sedation

               -moderate/ conscious sedation

               -Monitored anaesthesia care

               -General Anaesthesia(indication)

·          Ventilation details

·          Intraoperative Position

        Intraoperative  Clinical monitoring (non-invasive BP, invasive BP, pulse oxymetry, electrocardiography, fluid intake and output)

           Preoperative Antibiotic

           Sedative agents and doses

           Narcotic drugs and doses

          Induction drugs and doses

           Muscle relaxant and  doses

          Inhalation agents

           Local anaesthetics(lignocaine spray and viscous)

           Change in anaesthetic plan intraoperatively

          level of sedation during procedure(Ramsay sedation scale level 1-6)

Technique  

          Initial technical success

          Failure of Endoscopic Procedure and reason                           

           Drainage type conversion from  Endoscopic technique to Percutaneous Transhepatic Biliary Drainageg (PTBD)

          Type of stent inserted

          Period of biliary decompression-for S bilirubin to decrease by 1mg/dl

Complications during Procedure

          Episodes of desaturation-minimum O2 saturation during the procedure

       Any other Respiratory Complications during procedure - Respiratory depression (    hypoventilation (RR < 8/min), airway obstruction (due to anatomical structure or foreign body), laryngospasm (reflex closure or spasm of the glottic muscles, including the false and true vocal cords),bronchospasm(lower airway obstruction due to contraction or spasm of the bronchial smooth muscle due to an  anaphylactoid reaction or hyper-reactive airway in asthmatic patients), aspiration

          Need for emergency airway management- unanticipated emergency intubation or  emergency laryngeal mask airway insertion or  cricothyrotomy

            Cardiac complications-  hypotension, hypertension, tachycardia, Myocardial ischemia, Arrhythmias, pulmonary embolism, Cardiac arrest, requirement of inotropes

          Gastrointestinal  bleeding-

   Mild- Clinical evidence of bleeding (not just endoscopic); Hb level drop <3 g; no need for transfusion

   Moderate-Transfusion:

   Severe-transfusion: >/=5 units or intervention (angiographic or surgical)

          Extubation time 

          ICU admission  after endoscopic procedure and indication

          Duration of postoperative  ICU stay after procedure

          Failure to wean from ventilator  or  Ventilator requirement > 48 hours

          Any other Complications in the perioperative period.

Post procedure Complications within 30 days

          Post procedure  pancreatitis (abdominal pain and S amylase >3 x above normal after 24 hours) requiring admission and  if any intervention required

·         cholangitis - defined as an elevation in the temperature to more than 38deg because of a biliary cause without evidence of other concomitant infections.

·         sepsis or septic shock

·         bleeding or haemorrhage  requiring blood transfusion and  angiographic or surgical intervention

          Perforation

    Mild- slight leak of fluid or contrast dye; treatable by fluids and suction for %3 d

    Moderate- Any definite perforation treated medically for 4–10 d

    Severe- Medical treatment for more than 10d or intervention (percutaneous orsurgical)

          Stent dysfunction (increased bilirubin level after initial therapeutic success, without signs of cholangitis, requiring new bile duct cannulation

          EBD tube dislocation or removal or tube occlusion

         Cardiac Complications - Myocardial infarction (MI), cardiac arrest, and pulmonary embolism

          Cerebrovascular accident- stroke or new onset  neurologic deficit or coma

          Progressive renal insufficiency or  Ac renal failure +/- requiring renal replacement therapy, as defined by the KDIGO  classification/staging system

          Hepatic Insufficiency-defined as increase in liver enzymes AST/ALT(>2 times normal value,) or liver failure(ISGLS definition Grade A,B,C)

          Respiratory complications - Pneumonia

          Bile leak -  persisting after ERCP

          Indication for ICU readmission after discharge to wards

          Reintubation (unplanned)

         Hospitalisation after discharge

           need for intervention after discharge (percutaneous or surgical)

           length of hospital stay

         30 days mortality

ANALYSIS OF VARIABLES

Descriptive statistics number and percent of patients for categorical parameters as well as including mean+standard deviation will be presented. Comparisons of categorical variables will be made using Chi-square test or Fisher exact test. Comparison between continuous would be tested using the parametric or non-parametric test as appropriate. Level of significance P-value < 0.05 will be considered.