Influence of supraglottic airway device placement on cerebral hemodynamics.

BACKGROUND: Supraglottic airway devices (SGDs) are of current use in anesthesia practice and in emergency conditions. It has been suggested that cerebral blood flow (CBF) can decrease after SGD insertion or cuff inflation; however, it is uncertain if this reduction is caused by the SGD or the anesthetic drugs utilized for the anesthetic procedure. During minor surgery we separated CBF measurements by an adequate time interval in order to measure the distinctive changes in cerebral hemodynamics associated with anesthesia induction, SGD insertion and cuff inflation. METHODS: Patients scheduled for minor surgery requiring general anesthesia and SGD placement were included. Middle cerebral artery mean flow velocity (FVm-mca) and the Pulsatility Index (PI) were measured through use of trans-cranial Doppler (TCD) at baseline, after anesthesia induction, SGD insertion and cuff inflation, once a steady cardio-circulatory state was reached and end tidal CO2 (etCO2) was within normal range. RESULTS: A total of 21 patients were included. Following anesthesia induction, in concomitance to a reduction in mean arterial pressure (MAP), there was a mean decrease in FVm-mca by 16.60 cm/s, P<0.005 and a mean increase in PI by 0.24, P<0.0015. MAP, FVm-mca and PI did not change significantly, neither after SGD placement (P>0.05), nor after SGD cuffing (P>0.05). CONCLUSIONS: SGD insertion and cuff inflation did not influence cerebral hemodynamics in anesthetized patients undergoing minor surgery. At normal etCO2 range, the CBF reduction with transient increase in PI was associated with anesthesia induction and not SGD insertion itself.

Near-zero difficult tracheal intubation and tracheal intubation failure rate with the "Besta Airway Algorithm" and "Glidescope® in morbidly obese" (GLOBE).

BACKGROUND: Unpredicted Difficult Tracheal Intubation (DTI) with Macintosh occurs frequently in obese patients. We investigated the incidence of DTI using an algorithm based on preoperative assessment with the El-Ganzouri Risk Index (EGRI) and Glidescope® routine use. METHODS: We prospectively enrolled morbidly obese patients undergoing abdominal surgery. Patients were scheduled for Glidescope® intubation under general anesthesia if EGRI was <7 or awake Flexible Fiber-optic Intubation if EGRI was ≥7. The primary outcome was the DTI rate, defined as Cormack and Lehane grades ≥III, Intubation Difficulty Scale >5 and modified Intubation Difficulty Scale >5. Secondary outcomes included intubation success on the first attempt, the Time to Cormack, the time to intubation, failure to intubate, oxygen desaturation and difficult ventilation. RESULTS: Of the 214 patients enrolled, 212 (99%) were intubated with Glidescope® and 2 (1%) with awake Flexible Fiber-optic Intubation (one electively, one after a Glidescope® failure). There were no cases of DTI assessed using Cormack and Lehane and Intubation Difficulty Scale, and 3 cases (1.4%; 95% CI 0.45-4.29%) assessed using modified Intubation Difficulty Scale. Of the 213 patients intubated with Glidescope®, 185 (87%) had successful intubation on the first attempt. Mean Time to Cormack and time to intubation were 13.1 (SD 9.6) and 38.1 seconds (SD 21.1) respectively. We had one case (0.5%) of failed Glidescope® intubation and no cases of clinically significant complications. CONCLUSIONS: The incidence of DTI and Intubation Failure was reduced to near-zero using Glidescope® and the Besta Airway Algorithm in this sample of morbidly obese patients.

Influence of supraglottic airway device placement on cerebral hemodynamics.

BACKGROUND: Supraglottic airway devices (SGDs) are of current use in anesthesia practice and in emergency conditions. It has been suggested that cerebral blood flow (CBF) can decrease after SGD insertion or cuff inflation; however, it is uncertain if this reduction is caused by the SGD or the anesthetic drugs utilized for the anesthetic procedure. During minor surgery we separated CBF measurements by an adequate time interval in order to measure the distinctive changes in cerebral hemodynamics associated with anesthesia induction, SGD insertion and cuff inflation. METHODS: Patients scheduled for minor surgery requiring general anesthesia and SGD placement were included. Middle cerebral artery mean flow velocity (FVm-mca) and the pulsatility index (PI) were measured through use of trans-cranial Doppler (TCD) at baseline, after anesthesia induction, SGD insertion and cuff inflation, once a steady cardio-circulatory state was reached and end tidal CO2 (etCO2) was within normal range. RESULTS: A total of 21 patients were included. Following anesthesia induction, in concomitance to a reduction in mean arterial pressure (MAP), there was a mean decrease in FVm-mca by 16.60 cm/s, p<0.005 and a mean increase in PI by 0.24, p<0.0015. MAP, FVm-mca and PI did not change significantly, neither after SGD placement (p>0.05), nor after SGD cuffing (p>0.05). CONCLUSION: SGD insertion and cuff inflation did not influence cerebral hemodynamics in anesthetized patients undergoing minor surgery. At normal etCO2 range, the CBF reduction with transient increase in PI was associated with anesthesia induction and not SGD insertion itself.