Closed-circuit anesthesia preserves skin blood flow during surgery

BACKGROUND

Closed-circuit anesthesia (CCA) has been suggested to provide better hemodynamic stability, but the relative contribution of CCA to the control of blood flow in microcirculation is not defined. It is hypothesized that isoflurane-based CCA provides a favorable skin blood flow mediating via lesser circulatory response to surgical stimulation. This study was purposed to compare the effects of isoflurane conveyed by CCA with that by semiclosed anesthesia (SCA) on the preservation of skin blood flow in the forearm.

METHODS

Twenty seven patients scheduled for colorectal surgery were enrolled for the study and randomly assigned to one of two groups, either receiving CCA (n=14) or SCA (n=13). Anesthesia was induced with fentanyl (100 ig) and thiopental (4-5 mg/kg), and intubation was facilitated with pancuronium priming (0.015 mg/kg) and succinylcholine (1.25 mg/kg). Two percent isoflurane in high O2 flow (3 L/min) was given for 10 min to each patient initially to wash isoflurane in the functional residual capacity of both lungs and the breathing circuit. In the CCA group, after insoflurane wash-in the 02 flow was reduced less than 250 mL/min with isoflurane vaporizer setting adjusted to 3-5% to keep inspired isoflurane at 2% for maintenance of anesthesia. In patients of in the SCA group, anesthesia was maintained with isoflurane in 3 L/min O2 flow keeping the inspired isoflurane concentration at 2% throughout the surgery. A laser Doppler flowmetry (Moore instrument, Axminster, England) was used to measure skin blood flow (SBF) at the thenar eminence of left hand. Skin blood flow was determined and was taken as baseline (100%) at the 10th min after tracheal intubation. Thereafter, the magnitude of SBF was determined likewise every 30 minutes over the two-hour study. The hemodynamic and respiratory parameters were measured at every 5 minutes in both groups.

RESULTS

In comparison with the SCA group, the CCA group had a greater magnitude of skin blood flow (106 +/- 13% vs. 75 +/- 17%; 104 +/- 14% vs. 68 +/- 14% P < 0.01) at the 60th and 120th min. Also, patients who received SCA had higher mean arterial pressure (MABP) (82 +/- 8 vs. 78 +/- 8; 89 +/- 6 vs. 77 +/- 10, P < 0.05) and heart rate (HR) (80 +/- 9 vs. 73 +/- 9; 82 +/- 15 vs. 71 +/- 14, P < 0.05) at the 60th and 120th min.

CONCLUSIONS

Closed circuit technique for isoflurane anesthesia is feasible and advantageous. It not only facilitates favorable skin blood flow but also provides better hemodynamic stability in comparison with semiclosed technique for isoflurane anesthesia.

Clipping of the appendix induced cardiac arrest during appendectomy under spinal anesthesia

Bradycardia is commonly seen in high spinal anesthesia, however, evolution of cardiac arrest from sudden onset of severe bradycardia is infrequent. Prompt recognization and resuscitative measures are of paramount importance because they may insure a complete recovery without sequela as an aftermath. We report herein a case of severe sinus bradycardia induced by clipping of the appendix during appendectomy under spinal anesthesia with the sensory block up to T5 dermatome. Prompt intravenous atropine failed to regain normal sinus rhythm, and cardiac arrest ensued. Cardiac massage, manual ventilation with oxygen and low-dose epinephrine successfully resuscitated the patient. The possible mechanisms and management of this complication are also discussed.

Post-dural puncture arm and upper back pain--a report of two cases

The typical postdural puncture headache manifests as postural frontal, frontotemporal, or occipital headache, which is worsened by ambulation, and improved by decubitus. Accompanying symptoms are nausea, vomiting, and neck stiffness. Various rare presentations after dural puncture, such as upper back pain, arm pain, thoracic pain, bowel and bladder dysfunction have been sparsely reported. We report two cases who sustained arm and upper back pain after spinal anesthesia, and epidural blood patch gave them a complete relief of the symptoms.

The Interaction Effect of Perioperative Cotreatment with Dextromethorphan and Intravenous Lidocaine on Pain Relief and Recovery of Bowel Function After Laparoscopic Cholecystectomy

Both dextromethorphan (DM) and IV lidocaine improve postoperative pain relief. In the present study, we evaluated the interaction of DM and IV lidocaine on pain management after laparoscopic cholecystectomy (LC). One-hundred ASA physical status I or II patients scheduled for LC were randomized into four equal groups to receive either: (a) chlorpheniramine maleate (CPM) intramuscular injection (IM) 20 mg and IV normal saline (N/S) (group C); (b) DM 40 mg IM and IV N/S (group DM); (c) CPM 20 mg IM and IV lidocaine 3 mg . kg(-1) . h(-1) (group L); or (d) DM 40 mg IM and IV lidocaine (group DM+L). All treatments were administered 30 min before skin incision. Analgesic effects were evaluated using visual analog scale pain scores at rest and during coughing, time to meperidine request, total meperidine consumption, and the time to first passage of flatus after surgery. Patients of the DM+L group exhibited the best pain relief and fastest recovery of bowel function among groups. Patients in the DM and L groups had significantly better pain relief than those in the C group. The results showed an additional effect on pain relief and a synergistic effect on recovery of bowel function when DM was combined with IV lidocaine after LC.

[Rediffusion system and cuff pressure of Brandt's endotracheal tube]

During anesthesia increase of the endotracheal cuff pressure might be caused by anesthetic gases used, especially nitrous oxide (N2O), which easily diffuses into the cuff. In 1983, Brandt developed a blocking system which is called Rediffusion System. The principle of Rediffusion System is to make use of an enlarged pilot balloon to facilitate the removal of nitrous oxide which has diffused into the cuff during anesthesia. This study was designed to test and verify the function of Brandt tube's Rediffusion System during anesthesia using nitrous oxide as an anesthetic. Twenty four patients (age 19-82 yr; ASA physical status I-III) who underwent surgery under general anesthesia were allocated into three groups. For endotracheal intubation, in group I (n = 11) and group II (n = 5), Mallinckrodt Brandt tubes respective of internal diameter (ID) = 7 mm and ID = 8 mm were used, and in group III (n = 8) Portex Blue-line tubes with ID = 7 mm was used. Anesthesia was maintained with N2O, isoflurane, and oxygen and the FiN2O was kept around 50%. The cuff pressure was measured at the intervals of 30 min for 3 h. There were no significant differences of initial cuff volumes between group I and group II, but the initial cuff volumes of Portex blue-line tube were significantly larger than Brandt tubes at desired pressure level. Cuff pressures increased as the duration of anesthesia lengthened in all types of endotracheal tubes.(ABSTRACT TRUNCATED AT 250 WORDS)