Respiratory variation in aortic flow peak velocity and inferior vena cava distensibility as indices of fluid responsiveness in anaesthetised and mechanically ventilated children.

BACKGROUND AND AIMS: Dynamic parameters such as the respiratory variation in aortic flow peak velocity (ΔVpeak) and inferior vena cava distensibility index (dIVC) are accurate indices of fluid responsiveness in adults. Little is known about their utility in children. We studied the ability of these indices to predict fluid responsiveness in anaesthetised and mechanically ventilated children. METHODS: This prospective study was conducted in 42 children aged between one to 14 years scheduled for elective surgery under general endotracheal anaesthesia. Mechanical ventilation was initiated with a tidal volume of 10 ml/kg. ΔVpeak, dIVC and stroke volume index (SVI) were measured before and after volume expansion (VE) with 10 ml/kg of crystalloid using transthoracic echocardiography. Patients were considered to be responders (R) and non-responders (NR) when SVI increased to either ≥15% or <15% after VE. ΔVpeak and dIVC were analysed between R and NR. RESULTS: The best cut-off value for ΔVpeak as defined by the receiver operator characteristics (ROC) curve analysis was 12.2%, for which sensitivity, specificity, positive predictive value and negative predictive value were 100%, 94%, 96% and 100%, respectively, the area under the curve was 0.975. The best cut-off value for dIVC as defined by the ROC curve analysis was 23.5%, for which sensitivity, specificity, positive predictive value and negative predictive value were 91%, 89%, 91% and 89%, respectively, the area under the curve was 0.95. CONCLUSION: ΔVpeak and dIVC are reliable indices of fluid responsiveness in children.

Apneic Oxygenation during simulated prolonged difficult laryngoscopy: Comparison of nasal prongs versus nasopharyngeal catheter: A prospective randomized controlled study.

BACKGROUND: Apneic oxygenation by insufflating O2 through nasal prongs (NP) and nasopharyngeal catheter (NC) has been proven to be effective. We conducted this study to compare the relative efficacy of these two techniques in a simulated difficult airway situation. OBJECTIVE: The objective of this study is to evaluate the influence of two techniques of apneic oxygenation (NP vs. NC) on the duration of oxygen saturation ≥95% during simulated prolonged difficult laryngoscopy. METHODS: A randomized non-blinded study was conducted in 56 adult patients, 28 in each group belonging to American Society of Anesthesiologists physical status class I and II scheduled for elective surgical procedures under general endotracheal anesthesia randomized to either NC or NP group. After pre-oxygenating for an end tidal oxygen concentration of 90% and induction, ability to mask ventilate was checked and paralyzed with rocuronium. Apneic oxygenation using 5 L/min of O2 was established either by NP or NC. After laryngoscopy the laryngoscope was withdrawn to simulate a Grade 4 laryngoscopy and held in this position for an apnea time (T1) of 10 min with SpO2 maintained at ≥95% or until SpO2 dropped to < 95%, whichever is earlier. An arterial blood gas analysis was performed at the end of T1. Desaturation to < 95% were compared between the groups using Chi-square test (P < 0.05 as significant). Arterial blood gas analysis among those who sustained T1 for 10 min between the groups were compared using independent sample t-test (P < 0.05 was considered as significant). None of patients were excluded from the study. RESULTS: In NP group nine patients desaturated as against none in the NC group (P = 0.001). Arterial blood gas analysis among non-desaturated patients was comparable with respect to PO2, PCO2 and pH. CONCLUSION: Nasopharyngeal catheter is a better device than nasal prongs in maintaining safe oxygenation during apnea in a simulated prolonged difficult laryngoscopy.

Unilateral pulmonary edema after laparoscopic nephrectomy.

Unilateral-dependent pulmonary edema though reported in laparoscopic donor nephrectomies, has not been reported after laparoscopic non-donor nephrectomies. A 75-kg, 61-year-old man, a diagnosed case of right renal cell carcinoma was scheduled for laparoscopic nephrectomy. After establishing general anesthesia, the patient was positioned in the left-sided modified kidney (flank) position. During the 5.75-hour procedure, he was hemodynamically stable except for a transient drop in blood pressure immediately after positioning. Intra-abdominal pressure was maintained less than 15 mmHg throughout the procedure. Blood loss was approximately 50 mL and urine output was 100 mL in the first hour followed by a total of 20 mL in the next 4.75 hours. Total fluid received during the procedure included 1.5 L of Ringer's lactate and 1.0 L of 6% hydroxyethyl starch. After an uneventful procedure he developed respiratory distress in the postoperative period with a radiological evidence of dependent lung edema. Clinical and radiological improvement followed noninvasive ventilation, intravenous diuretics and oxygen therapy.

Posterior reversible encephalopathy syndrome at term pregnancy.

Posterior reversible encephalopathy syndrome (PRES) is a cliniconeuroradiological syndrome associated with various clinical conditions, presenting with headache, encephalopathy, seizures, cortical visual disturbances or blindness. Imaging predominantly shows parieto-occipital white matter changes, with vasogenic oedema being the most accepted pathophysiology. We report a 25-year-old primigravida who presented in term pregnancy with seizures and blindness, scheduled for emergency caesarean section. She was managed peroperatively under general anaesthesia and shifted to intensive care unit. Postoperative computed tomography brain revealed an intra-axial hypodensity involving predominantly white matter regions of bilateral parieto-occipital lobes, right caudate nucleus and right cerebellum, suggestive of PRES. Clinical improvement with complete resolution of visual disturbances was observed with supportive treatment. The importance of prompt suspicion and management in preventing short- and long-term neurological deficits in reversible condition like PRES is highlighted.