ABSTRACT
Although near-infrared spectroscopy (NIRS) enables bedside assessment of cerebral oxygenation, it provides little information on the cause of deoxygenation. The authors aimed to investigate the changes in cerebral oxygenation and haemoglobin concentration and their associations during paediatric cardiac surgery in order to elucidate the physiology underlying cerebral deoxygenation. An observational retrospective study on 399 patients who underwent paediatric cardiac surgery was conducted. With use of NIRS, cerebral oxygen saturation as expressed by tissue oxygen index (TOI) before and after surgery, concentration changes in oxygenated haemoglobin (Δ[HbO2]) and deoxygenated haemoglobin (Δ[HHb]) after surgery were studied as were the associations between these values and clinical variables. TOI decreased after surgery (preoperative versus postoperative value, 66.0% [56.9, 71.3] versus 63.2% [54.3, 69.4], median [25th, 75th percentile], P <0.001) and the decrease was greater in higher category groups in the Risk Adjusted Classification for Congenital Heart Surgery (RACHS-1). [HHb] increased from its baseline (+1.74 µmol/l [-1.57, +5.84], P <0.001) and the increase was greater in higher risk category groups. On the contrary, there was no evidence for a change in [HbO2] (+0.45 µmol/l [-4.76, +5.30], P=0.42). Cerebral oxygen saturation decreased after paediatric cardiac surgery and the decrease was greater in patients of higher risk groups. The increase in [HHb] was considered to play a predominant role in the cerebral deoxygenation noted, in particular in higher RACHS-1 category groups.
Subject(s)
Brain/metabolism , Cardiac Surgical Procedures , Hemoglobins/analysis , Oxygen/metabolism , Cerebrovascular Circulation , Child , Child, Preschool , Female , Heart Defects, Congenital/surgery , Humans , Infant , Male , Retrospective Studies , Spectroscopy, Near-InfraredSubject(s)
Anesthesia Recovery Period , Anesthesia , Oximetry/methods , Adolescent , Appendectomy , Biopsy , Child , Child, Preschool , Colon/surgery , Consciousness Monitors , Humans , Intraoperative Period , Male , Perfusion , PlethysmographyABSTRACT
BACKGROUND: Though controversial, the risk of pulmonary aspiration during general anaesthesia in the immediate postpartum period appears low. The efficacy of the Proseal laryngeal mask airway was studied prospectively in a group of patients undergoing postpartum tubal ligation. METHODS: The Proseal laryngeal mask airway was employed for airway management in 90 fasted patients undergoing tubal ligation via minilaparotomy at least 8 h after normal vaginal delivery (mean 36.5, range 8-96 h). Gastric volume and pH were measured, using aspiration through a gastric tube. RESULT: Proseal laryngeal mask airway insertion was successful in all patients, requiring one attempt in 75 patients (83%). The median (range) leak pressure was 35 (23-40) cmH2O. Twenty-two patients (25%) had a leak pressure of 40 cmH2O or greater. Gastric tube placement was successful in all patients, described as easy in 79 (87%), and difficult in 11 (13%). The mean initial volume of gastric aspirate was 10.7 (0-64) mL and the final volume 15.6 (0-71) mL. The mean pH of the gastric aspirate was 2.6 (1.2-6.6). There were no incidents of suspected fluid regurgitation or aspiration, but two patients required intubation during surgery. Ten patients (11.1%) complained of sore throat in the recovery room, nine of which were described as mild. All patients reported being satisfied with their anaesthesia. CONCLUSION: The Proseal laryngeal mask airway provides an effective airway for general anaesthesia in fasted patients undergoing tubal ligation from 8 h after normal vaginal delivery. While the safety of an unprotected airway in this population remains uncertain, this study suggested a low risk of regurgitation, especially in the first 24 h post partum.
