RESUMEN
Objectives: Middle ear barotrauma is a common complication of hyperbaric oxygen therapy (HBOT). Tympanostomy tube placement prevents barotrauma by facilitating middle ear equalization. We describe variations on techniques published by Mooney et al and Zhang et al for placing modified peripheral intravenous cannula (PIVC) ventilation tubes, which can be performed at the bedside under topical anesthesia. We aim to evaluate the safety and efficacy of this technique when performed to prevent otic barotrauma in patients undergoing HBOT. Methods: We performed an analytical observational study at a tertiary metropolitan Australian hospital with a state-wide adult hyperbaric service between 2018 and 2022. Patients were identified via unit audits. Patient, HBOT, and procedural factors were analyzed against complications using Fisher's exact test with Bonferroni correction and simple logistic regression. Results: Over 4 years, 112 patients (220 ears) underwent modified PIVC ventilation tube insertion. Mean age was 58.6 years (95% CI: 55.7-61.6, SD: 15.9). Thirty-eight patients (33.9%) were female, 74 (66.1%) were male. Thirty-four ears (15.5%) had preexisting barotrauma at the time of tympanostomy tube insertion. Patients underwent a mean of 11.5 dives (95% CI: 9.0-14.0, SD: 13.4), with ventilation tubes being required for a mean of 15.0 days (95% CI: 9.0-14.0, SD: 24.0) to complete HBOT. Fourteen ventilation tubes (6.4%) developed blockage during HBOT, and 12 (5.5%) prematurely extruded. Sixteen ears (7.3%) required reinsertion of ventilation tubes. Nine ears (4.1%) suffered barotrauma despite ventilation tube insertion. Conclusions: Otic barotrauma prophylaxis is paramount for safety during HBOT. We describe a safe, effective, and convenient technique for barotrauma prevention using modified PIVCs.
RESUMEN
BACKGROUND: It is uncertain whether increases in PaCO2 during surgery lead to an increase in plasma potassium concentration and, if so, by how much. Hyperkalaemia may result in cardiac arrhythmias, muscle weakness or paralysis. The key objectives were to determine whether increases in PaCO2 during laparoscopic surgery induce increases in plasma potassium concentrations and, if so, to determine the magnitude of such changes. METHODS: A retrospective observational study of adult patients undergoing laparoscopic abdominal surgery was perfomed. The independent association between increases in PaCO2 and changes in plasma potassium concentration was assessed by performing arterial blood gases within 15 min of induction of anaesthesia and within 15 min of completion of surgery. RESULTS: 289 patients were studied (mean age of 63.2 years; 176 [60.9%] male, and mean body mass index of 29.3 kg/m2). At the completion of the surgery, PaCO2 had increased by 5.18 mmHg (95% CI 4.27 mmHg to 6.09 mmHg) compared to baseline values (P < 0.001) with an associated increase in potassium concentration of 0.25 mmol/L (95% CI 0.20 mmol/L to 0.31 mmol/L, P < 0.001). On multiple regression analysis, PaCO2 changes significantly predicted immediate changes in plasma potassium concentration and could account for 33.1% of the variance (r2 = 0.331, f(3,259) = 38.915, P < 0.001). For each 10 mmHg increment of PaCO2 the plasma potassium concentration increased by 0.18 mmol/L. CONCLUSION: In patients receiving laparoscopic abdominal surgery, there is an increase in PaCO2 at the end of surgery, which is independently associated with an increase in plasma potassium concentration. However, this effect is small and is mostly influenced by intravenous fluid therapy (Plasma-Lyte 148 solution) and the presence of diabetes. Trial registration Retrospectively registered in the Australian New Zealand Clinical Trials Registry (Trial Number: ACTRN12619000716167).
