Sir,An 8-year-old girlchild of ASA PS Grade 1, weighing 22 kg, was posted for modified radical mastoidectomy for chronic otitis media. In the operating room, necessary monitoring and intravenous (IV) infusion of Ringer lactate was started. The induction was performed by an IV injection of propofol 40 mg, vecuronium 2 mg and fentanyl 30 μg, and endotracheal intubation was carried out after adequate muscle relaxation. Anaesthesia was maintained with nitrous oxide (66 vol%) and isoflurane (1 vol%) in O2. The depth of anaesthesia was adequate as the vital parameters were stable and the patient was receiving approximately a total MAC of 1.4 of inhalational agents. After cleaning, painting and draping, the surgeon injected 60 μg of adrenaline (3 mL of 1:50,000 freshly prepared solution by diluting 1 mg of adrenaline in 49 mL of normal saline [NS]) subcutaneously at the incision site behind the pinna after negative aspiration over a period of 15-20 s. Within 30 s of the injection, the heart rate (HR) and blood pressure (BP) increased from 106 beats per minute (bpm) to 200-210 bpm and from 110/70 to 198/110 mmHg, respectively. The procedure was stopped and the patient was administered 100% O2. Within 2-3 min, the airway pressures rose to 18 cmH2O from 10 cmH2O with coarse crepitations and expiratory wheeze in all lung fields. There were no signs of airway obstruction. O2 saturation (SpO2) was 85-90% at FiO2 of 1. BP decreased to 75/40 mmHg with a HR of 160-165 bpm. Lead II in the electrocardiogram (ECG) showed sinus tachycardia. A provisional diagnosis of acute congestive heart failure was made. Inj. furosemide 5 mg IV and Inj. dobutamine at 7 μg/kg/min were administered. A urinary catheter was also inserted. Intermittent IV doses of Inj. vecuronium 0.4 mg and Inj. midazolam 0.4 mg were given. Tracheal suctioning revealed frothy secretions. Over a period of 1 h, the crepitations and wheeze gradually improved. BP could be now maintained at 100/65 mmHg without inotropes. Urine output was 100 mL. The SpO2 was 99% on FiO2 of 1. Arterial blood gas showed pH of 7.35, pCO2 of 45mmHg, pO2152 mm Hg, BE -3mmol/l and bicarbonate of23mmmol/l. The trachea was extubated uneventfully after administration of reversal agent.After extubation, she was conscious and oriented. Her vitals were satisfactory (HR 140 bpm, BP 100/55 mmHg without any inotropes, respiratory rate 25/min) SpO2 was92% on air and 96% on venturi mask with FiO2 of 0.4. Auscultation showed few crepitations at the base of the lungs with normal heart sounds. The patient was shifted to the intensive care unit. Chest X-ray, 12-lead ECG, 2-D ECHO and serum electrolytes were normal and she was discharged from the ICU after 2 days.Skin and subcutaneous tissue infiltration with adrenaline prior to incision is a common practice in an attempt to decrease the vascularity of the tissues, which improves the surgical field view and reduces the blood loss while operating on a vascular field like head and neck surgeries. The maximum recommended dose of adrenaline for infiltration is 5-10 μg/kg, which may get altered due to simultaneous administration of inhaled anaesthetic agents.[1] It is noted that inhalational agents slow the automaticity of the sino-atrial node and myocardial conduction, resulting in atrial and ventricular arrhythmias, which are further potentiated by the use of exogenous adrenaline.[23] Johnston et al. calculated the ED50 of adrenaline that produces arrhythmia with halothane to be 2.1 μg/kg and with isoflurane to be 6.7 μg/kg.[1] However, there are case reports suggesting the occurrence of severe hypertension, tachycardia, pulmonary oedema, life-threatening arrhythmias and cardiac arrest on infiltration of only 20-30 μg of adrenaline.[45]Adding lignocaine to epinephrine has a protective action against cardiovascular complications as it stabilizes the myocardium by blocking sodium channels.[16] It is found that for subcutaneous infiltration, using 1:100,000 solution caused significant tachycardia than the 1:200,000 solution, and the 1:500,000 solution is virtually free of any side-effects with a significant decrease in blood loss.[78]In our case, the surgeon slowly injected 60 μg of adrenaline for infiltration, which was well within the recommended doses. The cardiovascular crisis precipitated by the small dose was unexpected and dramatic. It could be due to accidental intravascular placement of the drug. Repeated aspirations while injecting are recommended. Using 1-2% lignocaine with adrenaline for infiltration is preferred as it has a protective action against arrhythmias, but, in our case, adrenaline was diluted in NS. Also, 1:50,000 adrenaline was used as compared with the standard recommended concentration of 1:100,000-1:200,000.Thus, it can be concluded that there are chances of severe cardiovascular crisis even after small recommended doses of adrenaline. Hence, one should be cautious while adrenaline is being injected.