Young Jin Ro

I.V. infusion of magnesium sulphate during spinal anaesthesia improves postoperative analgesia

BACKGROUND In a randomized, double-blind, prospective study, we have evaluated the effect of i.v. infusion of magnesium sulphate during spinal anaesthesia on postoperative analgesia and postoperative analgesic requirements. METHODS Forty patients undergoing total hip replacement arthroplasty under spinal anaesthesia were included. After the induction of spinal anaesthesia, the magnesium group (Group M) received magnesium sulphate 50 mg kg(-1) for 15 min and then 15 mg kg(-1) h(-1) by continuous i.v. infusion until the end of surgery. The saline group (Group S) received the same volume of isotonic saline over the same period. After surgery, a patient-controlled analgesia (PCA) device containing morphine and ketorolac was provided for the patients. Postoperative pain scores, PCA consumption, and the incidences of shivering, postoperative nausea, and vomiting were evaluated immediately after surgery, and at 30 min, 4, 24, and 48 h after surgery. Serum magnesium concentrations were checked before the induction of anaesthesia, immediately after surgery, and at 1 and 24 h after surgery. RESULTS Postoperative pain scores were significantly lower in Group M at 4, 24, and 48 h after surgery (P<0.05). Cumulative postoperative PCA consumptions were also significantly lower in Group M at 4, 24, and 48 h after surgery (P<0.05). Postoperative magnesium concentrations were higher in Group M (P<0.05 at 4, 24, and 48 h after surgery), but no side-effects associated with hypermagnesemia were observed. Haemodynamic variables and the incidences of shivering, nausea, and vomiting were similar in the two groups. CONCLUSIONS I.V. magnesium sulphate administration during spinal anaesthesia improves postoperative analgesia.

Autonomic Changes in Preoperative Uncomplicated Diabetic Patients with Postural Changes

Diabetic autonomic neuropathy is a critical complication frequently encountered in anaesthetic and surgical practice. Power spectral analysis is a noninvasive tool for monitoring frequency analysis of heart rate variability (HRV) and autonomic control of the heart. This study examined HRV changes in preoperative diabetic patients without overt signs of autonomic dysfunction and in matched controls (n = 18 per group). HRV values at −15°, 0°, 15°, 45° and sitting positions were compared between groups and for each position. HRV in diabetic patients was lower than in controls at all positions (absolute units). Low-frequency power (normalized units) and the low-frequency/high-frequency ratio increased significantly at 45° and in sitting positions in controls but not in diabetic patients. Pre-existing autonomic derangements in diabetic patients without overt clinical symptoms can be aggravated by high-degree tilting or sitting positions. Consequently, great care should be taken during the intra- and perioperative management of these patients.

Phenylephrine Attenuates Intra-operative Hypothermia during Spinal Anaesthesia

Inadvertent hypothermia is common during spinal anaesthesia. This study was based on the hypothesis that phenylephrine might attenuate core hypothermia by inhibiting core-to-peripheral redistribution of body heat during spinal anaesthesia. In this prospective randomized study, 20 patients who underwent elective orthopaedic surgery under spinal anaesthesia were randomly assigned to receive either normal saline (control group) or continuously-infused phenylephrine 0.5 μg/kg per min (phenylephrine group). Core temperature, heart rate (HR) and mean arterial pressure (MAP) were monitored. Mean ± SE core temperature at the end of surgery was significantly higher in the phenylephrine-treated group compared with the control group (35.9 ± 0.1 °C versus 35.0 ± 0.1 °C, respectively), although there was no significant difference in baseline core temperature (both groups 36.3 ± 0.1 °C). Mean HR and MAP were not significantly different between the two groups. In conclusion, continuously-infused phenylephrine attenuated core hypothermia during spinal anaesthesia without any haemodynamic complications.

Combined use of autologous transfusion techniques to avoid allogeneic transfusion in spinal fusion surgery with instrumentation.

This study conducted a retrospective review of the medical records of 321 patients to delineate the efficacy of the combined use of autologous transfusion (AT) techniques. Transfusion profiles between an AT and homologous transfusion (HT) group were compared. A much lower proportion of patients were exposed to allogeneic blood in the AT group (13%) than in the HT group (98%, p < 0.001). In the AT group, a significantly smaller proportion of patients were exposed to allogeneic blood in patients transfused with three or four AT techniques (8%) than those with one or two techniques (29%, p < 0.05). A febrile reaction (11% of patients) after a reinfusion of post‐operatively shed blood was the only side effect associated with an AT. In conclusion, an AT is effective for preventing the exposure of allogeneic blood in spinal fusion surgery. The combined use of multiple AT techniques may further improve its efficacy.

Comparison of airwayscope to direct laryngoscope and lightwand for cardiovascular response in patients with difficult airway

BACKGROUND Airwayscope (AWS), which has been used successfully for difficult airway in general anesthesia, has been anticipated that hemodynamic response to tracheal intubation in the difficult airway may be attenuated. Also, there is a series of reports demonstrating the successful use of lightwand to open the difficult airway. Thus, we decided to conduct a survey to compare AWS to lightwand and to direct laryngoscopy of cardiovascular response to tracheal intubation. METHODS Of 64 healthy patients without cardiovascular disease, 22, 21, 21 patients were randomly assigned to AWS group, lightwand group and direct laryngoscope group. After induction of general anesthesia, intubation was performed with manual in-line neck stabilization. During laryngoscopy, a modified Cormack-Lehane grade was assessed and time to intubation was measured. Systolic arterial pressure (SAP) and heart rate (HR) were recorded at the following timepoints: baseline, just before intubation, 1 min, 2 min, 3 min, 4 min and 5 min after intubation. RESULTS There were no significant differences between the 3 groups in SAP, HR (P > 0.05). However modified Cormack-Lehane grade of all patients in the AWS group was I, while that in direct laryngoscope group was IIB or III. In addition, the mean time to intubation of the direct laryngoscope group was significantly longer than that of the AWS and lightwand (P < 0.05). CONCLUSIONS In the difficult airway, AWS was very effective in improving laryngeal view and decreasing time to intubation compared to direct laryngoscopey. In addition, lightwand reduced the time to intubation. However we could not find any significant difference in hemodynamic response to tracheal intubation among the 3 groups.