[Cardiac arrest secondary to pacemaker dysfunction during general anesthesia in a young adult patient]. / Arrêt cardiaque sur dysfonction de pacemaker au cours d'une anesthésie générale chez un adulte jeune.

The number of patients with cardiac pacemaker is continuously increasing. The anesthetic management of these patients is often trivialized, particularly during minor surgery. However there is always a potential risk of dysfunction during anesthesia. Perioperative management of these patients must be careful and standardized to avoid accidents. We report a case of cardiac arrest during general anesthesia for a day-surgery secondary to pacemaker dysfunction by increasing pacing thresholds in a young adult patient. Rapid onset after induction, without any surgical stimulation, has raised the question of the involvement of anesthetic drugs like propofol.

Abilities of pulse pressure variations and stroke volume variations to predict fluid responsiveness in prone position during scoliosis surgery.

BACKGROUND: Pulse pressure variation (PPV) and stroke volume variation (SVV) are robust indicators of fluid responsiveness in mechanically ventilated supine patients. The aim of the study was to evaluate the ability of PPV and SVV to predict fluid responsiveness in mechanically ventilated patients in the prone position (PP) during scoliosis surgery. METHODS: Thirty subjects were studied after the induction of anaesthesia in the supine position [before and after volume expansion (VE) with 500 ml of hetastarch 6%] and in PP (immediately after PP and before and after VE). PPV, SVV, cardiac output (CO), and static compliance of the respiratory system were recorded at each interval. Subjects were defined as responders (Rs) to VE if CO increased > or =15%. RESULTS: Three subjects were excluded. In the supine position, 16 subjects were Rs. PPV and SVV before VE were correlated with VE-induced changes in CO (r(2)=0.64, P<0.0001 and r(2)=0.56, P<0.0001, respectively). Fluid responsiveness was predicted by PPV >11% (sensitivity=88%, specificity=82%) and by SVV >9% (sensitivity=88%, specificity=91%). PP induced an increase in PPV and SVV (P<0.0001) and a decrease in the static compliance of the respiratory system (P<0.0001). In PP, 17 patients were Rs. PPV and SVV before VE were correlated with VE-induced changes in CO (r(2)=0.59, P<0.0001 and r(2)=0.55, P<0.0005, respectively). Fluid responsiveness was predicted in PP by PPV >15% (sensitivity=100%, specificity=80%) and by SVV >14% (sensitivity=94%, specificity=80%). CONCLUSIONS: PP induces a significant increase in PPV and SVV but does not alter their abilities to predict fluid responsiveness.

Pressure-controlled ventilation is superior to volume-controlled ventilation with a laryngeal mask airway in children.

BACKGROUND: This prospective, randomized, crossover study had two purposes: first, to determine whether pressure-controlled ventilation (PCV) is safer than volume-controlled ventilation (VCV) by preventing gastric insufflation in children ventilated through an laryngeal mask airway (LMA); second, to assess whether the measurement of LMA leak pressure (P(leak)) is useful for preventing leakage during positive pressure ventilation (PPV). METHODS: Forty-one, 2 to 15-year-old children underwent general anesthesia with an LMA. The expiratory valve was set at 30 cmH(2)O and P(leak) was measured using constant gas flow. Children were randomly ventilated using PCV or VCV for 5 min in order to reach a P(ET)CO(2) not exceeding 45 mm Hg, and then they were ventilated with the alternative mode. If the target P(ET)CO(2) could not be obtained in one mode, we switched to the other. If both modes failed, children were intubated. Tidal volumes, P(ET)CO(2) and airway pressures were noted and compared between modes. Gastric insufflation was checked by epigastric auscultation. RESULTS: PCV provided more efficient ventilation than VCV, as targeted P(ET)CO(2) was obtained without gastric insufflation using PCV in all cases except one, whereas VCV failed in three cases. No gastric insufflation occurred when ventilating below peak. CONCLUSIONS: These findings suggest that in the age group studied, PCV is more efficient than VCV for controlled ventilation with a laryngeal mask. Gastric insufflation did not occur with this mode.