Upper GI Endoscopy (OGD) — How It Works, Benefits & Recovery — Procedure Guide, Recovery & Risks | MyMedicPlus

Upper gastrointestinal endoscopy — commonly called gastroscopy, OGD (oesophago-gastro-duodenoscopy), or simply 'endoscopy' — is the direct visualisation of the oesophageal lumen, stomach, and proximal duodenum using a flexible, lighted, high-definition camera (gastroscope) approximately 9–11 mm in diameter and 100 cm long, inserted through the mouth. The gastroscope transmits a magnified, high-definition video image to a monitor, allowing the endoscopist to systematically examine the mucosa of all upper GI structures, identify pathology, take biopsies, and perform therapeutic interventions through a working channel in the scope. Gastroscopy is one of the most commonly performed procedures in medicine, with over 6 million procedures per year in the UK alone. It is performed by gastroenterologists, upper GI surgeons, and trained endoscopists in accredited endoscopy units. Modern gastroscopes with high-definition imaging and chromoendoscopy (virtual or chemical contrast enhancement) significantly improve early cancer detection compared to standard white-light endoscopy. Gastroscopy is one of the most common endoscopic procedures performed globally: over 2.5 million upper GI endoscopies are performed annually in England. Modern video endoscopes use high-definition imaging with digital enhancement technologies including narrow-band imaging (NBI), blue laser imaging (BLI), and linked colour imaging (LCI) to improve early neoplasia detection and Barrett's oesophagus assessment.

Gastroscopy is indicated for a wide range of upper GI symptoms and clinical scenarios. Symptomatic indications include: dysphagia (difficulty swallowing) at any age — requires urgent investigation to exclude oesophageal cancer; upper GI bleeding (haematemesis, melaena, positive faecal occult blood test) — emergency or urgent endoscopy for risk stratification and haemostasis; persistent dyspepsia or heartburn not responding to 4–8 weeks of proton pump inhibitor therapy in patients over 55 (NICE guidance); unexplained iron-deficiency anaemia; unintentional weight loss; and suspected gastric or oesophageal cancer. Surveillance and monitoring indications include: Barrett's oesophagus surveillance (every 3–5 years for non-dysplastic, annually for low-grade dysplasia); coeliac disease diagnostic biopsy (distal duodenum) and surveillance; gastric intestinal metaplasia and corpus atrophy monitoring; and post-gastrectomy surveillance. Diagnostic indications include: biopsy for Helicobacter pylori (CLO/urease test and histology), investigation for eosinophilic oesophagitis, and characterisation of submucosal lesions (GIST, carcinoid). Urgent therapeutic endoscopy is performed for oesophageal food bolus impaction, foreign body retrieval, and acute variceal haemorrhage.

Patients fast for a minimum of 6 hours (solid food) and 2 hours (clear fluids) before the procedure. Regular medications may be taken with a small sip of water; anticoagulants and antiplatelet agents are reviewed in advance by the endoscopy team. On arrival at the endoscopy unit, IV access is established. The pharynx is anaesthetised with lidocaine throat spray, which takes effect within 2–3 minutes, suppressing the gag reflex. IV sedation — typically midazolam 1–5 mg plus fentanyl 25–100 mcg — is administered for comfort; propofol deep sedation by an anaesthetist is available for anxious patients or complex procedures. The patient is positioned in the left lateral decubitus position with a bite guard protecting the scope. The lubricated gastroscope is gently introduced through the mouth and advanced through the pharynx, cricopharyngeus, into the oesophagus. The oesophageal lumen, gastro-oesophageal junction, stomach (antrum, body, fundus, cardia) and proximal duodenum (first and second parts) are systematically examined in a standardised sequence. Air or CO2 insufflation distends the lumen for visualisation. Biopsies are taken with cup forceps through the working channel. Polypectomy, injection haemostasis (adrenaline), thermal haemostasis (argon plasma coagulation, heater probe), endoscopic clips, band ligation (for varices), or dilation are performed as indicated. Procedure duration is 15–30 minutes for standard gastroscopy.

Gastroscopy provides the highest diagnostic accuracy for upper GI pathology of any available investigation — sensitivity 85–95% for clinically significant lesions including cancer, peptic ulcers, and oesophagitis. Unlike CT or barium studies, endoscopy enables simultaneous biopsy, H. pylori testing (CLO urease test: result within 1 hour, sensitivity 90%), and therapeutic intervention in a single session. Barrett's oesophagus surveillance by regular endoscopy detects dysplastic progression, enabling curative endoscopic mucosal resection (EMR) or radiofrequency ablation (RFA) before cancer develops — avoiding oesophagectomy and its associated 3–5% mortality. Endoscopic haemostasis achieves initial control of upper GI bleeding in 90%+ of cases, dramatically reducing the need for emergency surgery. Coeliac disease biopsy diagnosis from duodenal samples enables dietary management that prevents long-term complications including lymphoma and osteoporosis. In India, upper GI endoscopy costs approximately INR 3,000–8,000 (USD 35–100), compared to USD 700–2,000 in the USA or GBP 500–1,500 in the UK. The procedure is day-case, requiring only hours of fasting and a few hours of recovery.

Gastroscopy is a very safe procedure with a complication rate of under 1% in accredited endoscopy units. Aspiration pneumonia occurs in under 0.1% of cases and is minimised by adequate fasting and correct patient positioning. Throat soreness and bloating are common transient effects lasting 1–24 hours. Perforation is rare — approximately 1 in 5,000 diagnostic procedures; risk rises to 0.5–2% with therapeutic procedures such as oesophageal dilation. Perforation usually requires emergency surgical repair. Bleeding after therapeutic procedures (polypectomy, biopsy of vascular lesions) occurs in under 1% and is most often managed endoscopically. Adverse sedation reactions (respiratory depression, hypoxia, paradoxical agitation) occur in 0.1–0.5% — trained endoscopy nurses with reversal agents (flumazenil for benzodiazepines, naloxone for opioids) and resuscitation equipment manage these. Bacterial endocarditis prophylaxis is no longer routinely recommended for diagnostic gastroscopy per current NICE guidance. Missed lesions occur despite careful technique; second-look endoscopy may be warranted if symptoms persist.

Patients rest in the recovery area for 30–60 minutes until IV sedation has fully cleared and observations (blood pressure, oxygen saturation, consciousness level) are stable. Throat spray anaesthesia takes approximately 1 hour to fully resolve — no food or drink is taken until swallowing is fully restored to prevent aspiration. Once recovered, light food and fluids are permitted. Mild throat soreness, bloating, and transient nausea are expected for a few hours. Patients are discharged with a responsible adult and must not drive for 24 hours following IV sedation. Sedation also impairs memory and judgement — important decisions, alcohol, and operating machinery are avoided for 24 hours. Results of the visual examination are typically discussed with the patient immediately after the procedure. Biopsy results (H. pylori CLO urease test within 1 hour in some units; histology 5–7 working days) are communicated by letter or follow-up appointment. If taking anticoagulants paused for the procedure, these are restarted as advised by the endoscopy team (typically 24–48 hours post-procedure after biopsy). Any fever, increasing difficulty swallowing, severe chest or abdominal pain, or significant bleeding after discharge warrants immediate attendance to the emergency department.