Comparison of end-tidal carbon dioxide,oxygen saturation and clinical signs for the detection of oesophageal intubation

The reliability of various methods for detecting oesophageal intubation was assessed by means of a single blind study in rats. Both oesophagus and trachea were simultaneously intubated. The presence or absence of various clinical signs was noted during tracheal or oesophageal ventilation and arterial blood gases and end-tidal CO2 were measured. Oesophageal ventilation for one minute was associated with significant decreases (P less than 0.001) in pH, PaO2 and SaO2 and a significant (P less than 0.001) increase in PaCO2. Although mean PaO2 decreased by 70 per cent and mean SaO2 decreased by 31 per cent, 43 percent of rats failed to demonstrate a decrease in SaO2 below 85 per cent. Oxygen saturation was the least reliable method for detecting oesophageal intubation (sensitivity = 0.5, specificity = 0.9, positive predictive value (PPV) = 0.8). Chest movement was the most reliable clinical sign for detecting oesophageal intubation (sensitivity = 0.9, specificity = 1.0, PPV = 1.0). Oesophageal rattle was the second most reliable clinical sign (PPV = 0.9). Moisture condensation in the tracheal tube (PPV = 1.0) and abdominal distension (PPV = 0.9) were judged to be the least reliable because each had a high false negative rate of 0.3. The most reliable method for the early detection of oesophageal intubation in rats was end-tidal, CO2 (sensitivity 1.0, specificity = 1.0, PPV = 1.0). In addition, end-tidal CO2 when used in conjunction with the four clinical signs improved the reliability of these signs.     

Refractory dystonia during propofol anaesthesia in a patient with torticollis-dystonia disorder

Purpose

To report a case of refractory dystonia under propofol anaesthesia in a patient with Torticollis-Dystonia disorder.

Clinical features

A 38-yr-old man presented for an MRI scan for investigation of a Torticollis-Dystonia disorder. There was a biphasic response to propofol with complete amelioration of the torticollis and limb dystonia initially with subsequent recurrence under deep propofol anaesthesia. Coadministration of midazolam, diazepam, and thiopentone were not successful in abolishing the recurrent dystonia.

Conclusions

Propofol should preferably be avoided in patients with torticollis and dystonias. Where complete control of movements is required, it may be necessary to consider general endotracheal anaesthesia with muscle relaxants.     

Electrocardiographic monitoring in healthy young adult outpatients: mandatory or optional?

Purpose

To determine the incidence and duration of ECG abnormalities in healthy adults during short duration outpatient surgery and their relationship to important clinical events.

Method

In 381, ASA Class I, day surgery patients undergoing short surgical procedures the ECG was monitored prospectively for evidence of abnormalities. The attending anaesthetist administered the anaesthetic and made all clinical decisions while relying on routine monitors (ECG, oximeter, BR capnometer, oxygen analyser, low pressure alarm and anaesthetic gas monitors). Intra-operative events of clinical significance (e.g., light anaesthesia, regurgitation, coughing, hypotension, arterial desaturation, hiccoughs etc), ECG abnormalities and their duration were documented.

Results

Electrocardiographic abnormalities were detected in 21 % of patients as follows: sinus tachycardia (11 %), artifacts (7%), premature atrial contractions (1.6%), lead disconnects (1%), sinus bradycardia (0.5%) and premature ventricular contractions (0.3%). All abnormalities resolved spontaneously within three minutes. Intra-operative incidents of consequence occurred in only 2.6%: light anaesthesia (5), arterial desaturation > 5% (2), hypotension (1), hiccough (1) and régurgitation (1). All incidents were detected clinically and by pulse oximetry. The ECG did not detect any of the incidents and was normal during the events.

Conclusion

Routine ECG monitoring did not detect intra-operative incidents in healthy adults during short outpatient procedures. Detected ECG abnormalities were benign and resolved spontaneously within three minutes. Firm conclusions as to the safety implications of withdrawing ECG monitoring cannot be drawn from this study. Guidelines may need to be reviewed to determine whether ECG monitoring in such cases should be optional rather than mandatory.     

Case report: Sequential bilateral upper extremity intravenous regional anesthesia with chloroprocaine

Purpose

This case report describes the novel use of sequential bilateral upper extremity intravenous regional anesthesia with 2-chloroprocaine for bilateral endoscopic carpal tunnel decompression.

Clinical features

A 49-yr-old female, American Society of Anesthesiologists physical status I, presented for outpatient bilateral carpal tunnel release. Sequential bilateral intravenous regional anesthesia was performed with 0.5% 2-chloroprocaine 30 mL per arm using a double upper arm tourniquet. Intraoperative sedation consisted of midazolam and fentanyl. Tourniquet times for the right and left arms were 28 and 19 min, respectively. After deflation of each tourniquet, mild limb twitching occurred but resolved immediately after administration of intravenous midazolam. The patient made a rapid recovery, and she was discharged home uneventfully.

Conclusions

Bilateral sequential intravenous regional anesthesia with 2-chloroprocaine is effective for upper extremity surgery of short duration. Recommendations to minimize the risk of local anesthetic toxicity are reviewed.     

A randomized controlled trial investigating rectus sheath catheters following radical cystectomy

Objective

To evaluate whether rectus sheath catheter (RSC) insertion may be an alternative to thoracic epidural (TE).

Patients and Methods

In a non-blinded, single-centre, non-inferiority study, patients undergoing open radical cystectomy were randomized 1:1 to receive either a TE or surgically placed RSC. The primary endpoint was cumulative opiate use (median oral morphine equivalent [OME]) in the first 72 h postoperatively. Secondary outcomes included visual analogue scale pain scores, measures of postoperative recovery including mobility and time to regular diet, and complications.

Results

Ninety-seven patients were randomized (51 TE, 46 RSC). The median OME was 103 (77.5–132.5) mg in the TE arm and 161.75 (117.5–187.5) mg in the RSC arm. A Mann–Whitney U-test confirmed non-inferiority of RSC to TE at a threshold of 15 mg OME (P = 0.002). When comparing pain scores for the first three postoperative days, an early difference was observed that favoured the TE group during post-anaesthesia care unit stay, which was lost after postoperative day 1. Patient satisfaction with analgesia on the third postoperative day was similar in the two arms (P = 0.47). There were no statistically significant differences between arms with respect to the other secondary outcomes.

Conclusions

The outcomes from this prospective randomized trial demonstrated non-inferiority of RSC insertion compared to TE with respect to 72-h opiate use. Patient satisfaction with pain control on postoperative day 3 was the same for each group.     

Non-alkalinized and alkalinized 2-chloroprocainevs lidocaine for intravenous regional anesthesia during outpatient hand surgery

PURPOSE: Chloroprocaine should be an ideal agent for intravenous regional anesthesia (IVRA) because of its rapid onset and ester hydrolysis. Raising the pH of local anesthetics may increase the speed of onset and the intensity of nerve blocks. We compared plain and alkalinized 2-chloroprocaine 0.5% with lidocaine for IVRA. METHODS: In two separate double-blind studies, 78 patients scheduled for daycare hand surgery were randomized to receive 40 mL plain 2-chloroprocaine 0.5%, alkalinized 2-chloroprocaine 0.5% or lidocaine 0.5% for IVRA. Time to sensory and motor block, need for supplemental analgesia, and side effects were compared. RESULTS: There was no difference in time to sensory or motor block in either group. Patients who received plain chloroprocaine required more supplemental opioid and had a higher incidence of metallic taste and of hives than patients who received lidocaine (P < 0.05). Comparing alkalinized chloroprocaine with lidocaine, there was no difference found with respect to opioid supplementation, CNS side effects, or incidence of hives. CONCLUSION: In conclusion, alkalinized chloroprocaine was found to be an effective agent for IVRA but no benefit over lidocaine was detected. Plain chloroprocaine for IVRA produced more minor side effects than lidocaine.     

Pharmacoeconomics of intravenous regional anaesthesiavs general anaesthesia for outpatient hand surgery

Purpose

To compare the cost and effectiveness of intravenous regional anaesthesia (IVRA) with general anaesthesia (GA) for outpatient hand surgery.

Method

A retrospective record analysis of 121 patients who received IVRA were compared with 64 patients who received GA in our Daycare centre. The costs of anaesthesia and recovery were calculated from an institutional perspective using 1995 Canadian Dollar values. Effectiveness was measured in terms of time for anaesthesia, recovery and discharge, % with unsatisfactory anaesthesia and complications.

Results

Both groups were well matched in terms of weight, sex and ASA class. Patients in the IVRA group were older (45 ± 16 vs 38 ± 13 yr) and had a lower frequency of two types of operation. The median total cost for the IVRA group of $24.60 (15.76–55.29) was less than that for the GA group of $48.66 (35.59–73.11). (P < 0.00001). Anaesthesia was unsatisfactory in 11% of the IVRA group, but in none having GA, (P < 0.01). Recovery was faster in the IVRA group with a median time to discharge of 70 (35–180) min compared with 118 (45–320) min in the GA group. (P < 0.00001) Vomiting requinng treatment occurred in 5% of the GA group, but in none having IVRA, (P < 0.05). Dizziness which delayed discharge also occurred in 5% of the GA group, but in none having IVRA. (P < 0.05).

Conclusion

The cost of anaesthesia and recovery using IVRA for outpatient hand surgery was half that of GA. Intravenous regional anaesthesia was less effective than GA in achieving satisfactory anaesthesia, equally effective in time to administer anaesthesia, and more effective in speeding recovery and minimising postoperative complications.