ABSTRACT
BACKGROUND.: Apnoeic oxygenation during anaesthesia has traditionally been limited by the rapid increase in carbon dioxide and subsequent decrease in pH. Using a Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) technique a slower increase in carbon dioxide than earlier studies was seen. Notably, apnoeic oxygenation using THRIVE has not been systematically evaluated with arterial blood gases or in patients undergoing laryngeal surgery. The primary aim of this study was to characterize changes in arterial P O 2 , P CO 2 and pH during apnoeic oxygenation using THRIVE under general anaesthesia. METHODS.: Adult patients, (ASA I-II), undergoing shorter laryngeal surgery under general anaesthesia, were oxygenated during apnoea using THRIVE, 100% oxygen, 40-70 litres min - 1 . A cohort was randomized to hyperventilate during pre-oxygenation. Vital parameters and blood gases were monitored. RESULTS.: Thirty-one patients, age 51 (34-76) yr, BMI 25 (4) were included. Mean apnoea time was 22.5 (4.5) min. Patients were well oxygenated, S pO 2 was never below 91%. The increase in P aCO 2 and end-tidal CO 2 during apnoea was 0.24 (0.05) and 0.12 (0.04) kPa min -1 , respectively. Hyperventilation during pre-oxygenation generated no difference in P aCO 2 at the end of apnoea compared with normoventilation. CONCLUSIONS.: This physiological study of apnoeic oxygenation using THRIVE during laryngeal surgery shows that this technique is able to keep patients with mild systemic disease and a BMI <30 well oxygenated for a period of up to 30 min. The THRIVE concept makes it possible to extend the apnoeic window but monitoring of CO 2 and/or pH is recommended. CLINICAL TRIAL REGISTRATION.: NCT02706431.
Subject(s)
Anesthesia, General/methods , Apnea/metabolism , Insufflation/methods , Respiration, Artificial/methods , Adult , Aged , Airway Management , Carbon Dioxide/blood , Female , Hemodynamics/drug effects , Humans , Hydrogen-Ion Concentration , Hypercapnia , Larynx/surgery , Male , Middle Aged , Oxygen/blood , Oxygen Inhalation Therapy , Pulmonary Gas Exchange , Risk FactorsABSTRACT
Epidural blood patching is an effective treatment for postdural puncture headache but has potential risks. Arachnoiditis is a very rare disabling condition and few cases have been described following an epidural blood patch. We present a case of chronic adhesive arachnoiditis in a parturient treated with a repeat epidural blood patch. A healthy 29-year-old woman had an accidental dural puncture following epidural insertion during labour. Initial treatment of postdural puncture headache with an epidural blood patch was ineffective and was therefore repeated. She gradually developed severe neurological symptoms consistent with arachnoiditis confirmed with magnetic resonance imaging. Despite intensive multimodal treatment with analgesics and physiotherapy, her neurological condition remains unresolved two years later. This serious but rare complication should encourage caution when treating parturients with postdural puncture headache with a repeat epidural blood patch.
