rocuronium and Hypercapnia

Obstructive sleep apnoea and residual neuromuscular blockade are, independently, known to be risk factors for respiratory complications after major surgery. Residual effects of neuromuscular blocking agents are known to reduce the hypoxic ventilatory response in healthy volunteers. Patients with obstructive sleep apnoea have impaired control of breathing, but it is not known to what extent neuromuscular blocking agents interfere with the regulation of breathing in such patients. In a physiological study in 10 unsedated men with untreated obstructive sleep apnoea, we wished to examine if partial neuromuscular blockade had an effect on hypoxic ventilatory response (isocapnic hypoxia to oxygen saturation of 80%) and hypercapnic ventilatory response (normoxic inspired carbon dioxide 5%). The hypoxic ventilatory response was reduced by 32% (p = 0.016) during residual neuromuscular block (rocuronium to train-of-four ratio 0.7), but the hypercapnic ventilatory response was unaffected. We conclude that neuromuscular blockade specifically depresses peripheral chemosensitivity, and not respiratory muscle function since the hypercapnic ventilatory response was unaffected.

Topics: Adolescent; Adult; Aged; Carbon Dioxide; Humans; Hypercapnia; Hypoxia; Male; Middle Aged; Neuromuscular Blockade; Neuromuscular Nondepolarizing Agents; Oxygen; Prospective Studies; Pulmonary Ventilation; Respiratory Muscles; Risk Factors; Rocuronium; Sleep Apnea, Obstructive; Young Adult

Impaired cerebrovascular reactivity (CVR) is an important prognostic marker of stroke. Most measures of CVR lack (1) a reproducible vasoactive stimulus and (2) a high time and spatial resolution measure of cerebral blood flow (CBF), particularly for mechanically ventilated patients. The aim of our study was to investigate the feasibility of measuring CVR using sequential gas delivery circuit and gas blender for precise targeting of end-tidal PCO. Four patients with known moyamoya disease requiring preoperative CVR measurements under general anesthesia were studied. All patients had standard anesthesia induction and maintenance with intravenous propofol and rocuronium. Patients were intubated and manually ventilated with a self-inflating bag connected to a sequential breathing circuit. A computer-controlled gas blender supplied the gas mixture in proportions to attain target PetCO. CVR studies were successfully performed on all patients, and the CVR values were lower in both gray and white matter bilaterally when compared with healthy volunteers. In addition, CVR maps in 3 patients showed intracerebral steal phenomenon in spite of having had cerebral revascularization procedures, indicating that they are still at risk of cerebral ischemia.. BOLD-MRI CVR studies are feasible in mechanically ventilated patients anesthetized with propofol.

Topics: Administration, Intravenous; Adolescent; Androstanols; Anesthesia, General; Anesthetics, Intravenous; Biomarkers; Cerebral Arteries; Cerebrovascular Circulation; Cerebrovascular Disorders; Feasibility Studies; Female; Humans; Hypercapnia; Image Interpretation, Computer-Assisted; Magnetic Resonance Angiography; Magnetic Resonance Imaging; Male; Moyamoya Disease; Neuromuscular Nondepolarizing Agents; Oxygen; Perfusion Imaging; Pilot Projects; Predictive Value of Tests; Propofol; Respiration, Artificial; Rocuronium; Young Adult

Topics: Androstanols; Anti-Bacterial Agents; Cefazolin; Conscious Sedation; Electroencephalography; Female; Humans; Hypercapnia; Medication Errors; Middle Aged; Monitoring, Physiologic; Neuromuscular Nondepolarizing Agents; Rocuronium; Stupor