SummaryA patient with a large anterior mediastinal mass with minimal respiratory symptoms presented for a diagnostic biopsy of the mass. A pre-operative thoracic computed tomographic scan demonstrated narrowing of the distal trachea, and right and left main stem bronchi. An awake intubation was done. Thiopentone and muscle relaxant were given and surgery commenced. High airway pressure developed and ventilation became difficult, although oxygenation remained satisfactory throughout. Anaesthetic implications are discussed. We recommend that patients with more than 50% obstruction of the airway at the level of the lower trachea and main bronchi have their femoral vessels cannulated in readiness for cardiopulmonary bypass. Anterior mediastinal masses are uncommon, but when they present at surgery for diagnostic or for definitive procedures, they pose serious challenges for the anaesthetist. By nature of their anatomical location, they produce three problems: compression of the heart, compression of the large vessels (principally the superior vena cava) and compression of the trachea and main bronchi. Compression of the airway can be insidious when it is intrathoracic and at the bronchial level. Thus, a patient can be asymptomatic and yet have airway compression which only manifests at induction of anaesthesia when voluntary control of the airway is lost. The anaesthetist who is unprepared will face a catastrophic situation of total obstruction of the airway leading to death of the patient.We report a case of a massive anterior mediastinal mass causing intrathoracic airway obstruction during which some anaesthetic problems arose. We also reviewed the literature and, in the light of this, present our recommendations for the management of patients with such masses. Case historyA 20-year-old Malay woman presented for a diagnostic biopsy of an anterior mediastinal mass. She had a history of a cough for one month. There was no history of dyspnoea, stridor or noisy breathing. Chest X-ray showed a massive mediastinal mass filling more than two-thirds of the chest (Figs 1 and 2) and a computed tomographic scan confirmed this finding as well as compression of both main bronchi (Figs 3 and 4).An awake intubation was done with fentanyl 100 mg, and topical anaesthesia of the oropharynx. A size 7 tracheal tube was inserted easily past the cords. Bilateral breath sounds were ascertained and the tracheal tube secured. Initial manual ventilation showed no increase in peak airway pressures. Thiopentone and atracurium were administered, anaesthesia was maintained with isoflurane and surgery commenced. It was then noticed that the peak airway pressure had increased to 50 cmH 2 O. Auscultation of the lungs revealed coarse rhonchi in both inspiration and expiration. Treatment was instituted for what was diagnosed as bronchospasm, with salbutamol given through the breathing system. There was no change in the lung sounds. Paper 961 670ᮊ 1999 Blackwell Science Ltd biopsy. A frozen section revealed a lymphoma and surgery was terminated. Mu...
The outbreak of coronavirus disease 2019 (COVID-19), a respiratory disease from a novel coronavirus that was first detected in Wuhan City, Hubei Province, China, is now a public health emergency and pandemic. Singapore, as a major international transportation hub in Asia, has been one of the worst hit countries by the disease. With the advent of local transmission, the authors share their preparation and response planning for the operating room of the National Heart Centre Singapore, the largest cardiothoracic tertiary center in Singapore. Protection of staff and patients, environmental concerns, and other logistic and equipment issues are considered.
SummaryMapleson used a computer spreadsheet model to predict the theoretical ideal fresh gas flow sequence at the start of low-flow anaesthesia. The aim was to increase the end-expired partial pressure of inhalational agent (P E H an ) to one minimum alveolar concentration (MAC) as quickly as practicable and then to keep it constant. Ninety adult patients undergoing elective tonsillectomy under general anaesthesia were randomly allocated to one of three groups (n 30) to receive isoflurane, sevoflurane or desflurane in oxygen. Fresh gas flow and vaporiser settings as specified by Mapleson were followed in all cases except that the maximum setting for desflurane was 18% (2.7 MAC instead of 3 MAC). Recordings of P E H an were made at 1, 2, 3, 4, 5, 7, 10, 15 and 20 min. Mean values of P E H an exceeded 1 MAC by 2 min in all three groups and remained above this value throughout. Each group's P E H an measurements were divided by their respective 1-MAC value. A simple two-level model (with patients at level 2 and time at level 1), with measurements at 1 min excluded, showed that the fitted value at 2 min and the time-weighted mean for 2±20 min for P E H iso ( .182]) were significantly higher than their respective 1-MAC values. The Mapleson concept of an initial high fresh gas flow and high vaporiser settings, followed first by reduced high fresh gas flow, as followed in this clinical study, results in P E H an values close to or slightly higher than predicted in the spreadsheet model. Mapleson used a computer spreadsheet model to predict the theoretical ideal fresh gas flow sequence at the start of low-flow anaesthesia [1]. Physiological and pharmacokinetic parameters for an anaesthetised 70 kg`standard man' were used [2±5]. A closed circle system consisting of connecting tubes each with a capacity of 1.0 l and a 1.5-l sodalime canister were specified. The general objective of rapid induction' was expressed specifically as being to increase the end-expired partial pressure of inhalational agent (P E H an ) to one minimum alveolar concentration (MAC) as quickly as practicable and then to keep it constant, with minimum usage of the inhaled anaesthetic.The aim of this study was to test the accuracy of thè Mapleson model' in the clinical setting during controlled mechanical ventilation using isoflurane, sevoflurane or desflurane in oxygen.
Propofol formulated in medium- and long-chain triglycerides (MCT/LCT) is thought to cause less pain on injection. In this study we sought to determine if adding lidocaine to propofol-MCT/LCT is more effective in decreasing pain compared with propofol-MCT/LCT alone or conventional propofol-lidocaine mixtures. Seventy-five patients were randomized into three groups. Group A received conventional propofol-lidocaine mixtures with 20 mg lidocaine, group B received propofol-MCT/LCT with saline, and group C received propofol-MCT/LCT with 20 mg lidocaine. The incidence of pain was 24% in groups A and B and 4% in group C. The number needed to treat to prevent pain was 5. We conclude that propofol-MCT/LCT-lidocaine mixtures significantly reduce pain.
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