Anesthetic management of a parturient with mixed mitral valve disease and uncontrolled atrial fibrillation.

This case report describes the anesthetic management of a 32-year-old parturient with combined severe mitral regurgitation and moderate mitral stenosis, complicated by fast atrial fibrillation. The advantageous effects of epidural analgesia during labor and vaginal delivery and the importance of invasive monitoring are discussed. We also report the rare complication of right bundle branch block related to the use of a pulmonary artery catheter.

Preventing pain during injection of propofol: the optimal dose of lidocaine.

STUDY OBJECTIVE: To define the optimal dose of lidocaine to be added to propofol to reduce the incidence of pain during its injection. DESIGN: Double-blind, randomized, placebo-controlled study. SETTING: Medical center operating rooms. PATIENTS: 135 ASA I and II female patients undergoing minor outpatient surgery. INTERVENTIONS: Patients were randomly allocated to one of five groups: Group A (control), no lidocaine: Group B, lidocaine 10 mg: Group C, lidocaine 20 mg; Group D, lidocaine 30 mg; Group F, lidocaine 40 mg. For each patient, pain during injection of the propofol solution was graded as none, mild, moderate, or severe. MEASUREMENTS AND MAIN RESULTS: The incidence of pain in the control group was 85%. All treatment groups receiving lidocaine had a significantly lower incidence of pain compared with the control group (P < 0.001). The lidocaine 30 mg and 40 mg groups both had a 7% incidence of pain, which was significantly less than a 33% incidence in the lidocaine 10 mg group (P < 0.05). CONCLUSIONS: Within this dose range and in this patient population, 30 mg of lidocaine is optimal for reducing the pain during injection of propofol.

Tracheal intubation through the laryngeal mask airway using a gum elastic bougie: the effect of head position.

STUDY OBJECTIVE: To determine the effect of head position on success of tracheal intubation through a Laryngeal Mask Airway (LMA) using a gum elastic bougie. DESIGN: Randomized, controlled study. SETTING: Anesthesia and operating rooms of the University Hospital, Nottingham, UK. PATIENTS: 20 patients scheduled to undergo routine elective surgery requiring the use of an LMA for anesthesia. INTERVENTIONS: Blind placement of a gum elastic bougie through an LMA in two head positions. MEASUREMENTS AND MAIN RESULTS: Final position of the gum elastic bougie after removal of the LMA as determined by fiberoptic laryngoscopy. The gum elastic bougie was correctly sited in the trachea in the classical intubating position in 4/20 (20%) and in the neutral position in 0/20 (0%). There was no difference in the success of this technique between the two head positions. CONCLUSIONS: This technique cannot be recommended as an alternative to direct laryngoscopy following a failed intubation.

Role of the laryngeal mask airway in the immobile cervical spine.

STUDY OBJECTIVE: To determine whether the laryngeal mask airway has a useful role in the airway management of patients whose cervical spines are immobilized in a rigid cervical collar. DESIGN: A randomized study comparing the difficulty, rapidity, and success rate of ventilating patients with immobilized cervical spines using a laryngeal mask airway and an endotracheal tube. SETTING: Medical center surgical unit. PATIENTS: Twenty-eight ASA physical status I and II women scheduled to undergo elective gynecologic surgery requiring general anesthesia. INTERVENTIONS: Tracheas of all anesthetized patients were sequentially intubated with an endotracheal tube and had a laryngeal mask inserted in random order. MEASUREMENTS AND MAIN RESULTS: Mouth opening was measured, and a Mallampati classification was made in each subject both with and without a rigid Philadelphia collar in situ. The view at laryngoscopy was recorded. The time taken to insert both devices to allow for satisfactory ventilation and the degree of difficulty encountered were determined. With a cervical collar in situ, mouth opening was reduced up to 60%. The Mallampati assessment and laryngoscopic view were shifted to one suggestive of a more difficult intubation. The time taken to ventilate these patients and the difficulties encountered were significantly less when using the laryngeal mask (p = 0.0001). A successful outcome was more likely following insertion of the laryngeal mask than when attempting intubation with an endotracheal tube. CONCLUSIONS: The laryngeal mask airway compared favorably with an endotracheal tube in success rate, difficulty of insertion, and time to position correctly in this patient population. Although the laryngeal mask does not reliably protect against aspiration, we believe it may play a useful role if more conventional methods of airway management fail. Further studies in the trauma scenario are indicated.

Nebulized bupivacaine attenuates the heart rate response following tracheal intubation.

STUDY OBJECTIVE: To determine whether nebulized bupivacaine attenuates the acute hemodynamic response to laryngoscopy and intubation. DESIGN: Prospective, randomized, placebo-controlled study. SETTING: Operating room at a university medical center. PATIENTS: 40 health ASA physical status I and II patients scheduled for minor surgical procedures. INTERVENTIONS: Patients were randomized to receive 4 ml of a nebulized solution of either saline (n = 20) or 0.75% bupivacaine (n = 20) 15 minutes before induction of anesthesia. On completion of the aerosol treatment, fentanyl 1.5 micrograms/kg was given intravenously (i.v.), and 3 minutes later anesthesia was induced with thiopental sodium 5 mg/kg i.v. and succinylcholine 1.5 mg/kg i.v.. Laryngoscopy was begun 60 seconds after induction, and the trachea was intubated at 90 seconds. Anesthesia was maintained with 50% nitrous oxide in oxygen following intubation, and 1% isoflurane was administered at 180 seconds. MEASUREMENTS AND MAIN RESULTS: Heart rate (HR) and blood pressure were recorded automatically every 30 seconds for 5 minutes. Bupivacaine significantly attenuated HR (p < 0.05) but not the hypertensive response to laryngoscopy and intubation. CONCLUSION: Nebulized 0.75% bupivacaine was only partially effective in blunting the hemodynamic response to tracheal intubation.

Effect of preincision versus postincision infiltration with bupivacaine on postoperative pain.

STUDY OBJECTIVE: To compare the efficacy of preincision wound infiltration with bupivacaine to wound infiltration at the end of the operation. DESIGN: A prospective, randomized, double-blind study. SETTING: University medical center. PATIENTS: 56 ASA status I and II women scheduled for abdominal hysterectomy were randomly assigned to one of three treatment groups. INTERVENTIONS: Group 1 (control) received no local anesthetic infiltration. Group 2 received subcutaneous infiltration with 40 ml of bupivacaine 0.5% (pH 6.9) 15 minutes prior to incision. Group 3 received wound infiltration with a similar solution at the end of surgery. Anesthesia was induced with thiopental 3.0 mg/kg i.v., droperidol 50 micrograms/kg i.v., and sufentanil 0.5 microgram/kg i.v. and maintained with nitrous oxide 67% in oxygen and sufentanil 0.1 microgram/kg IV boluses as required. Postoperative pain was treated with morphine via a patient-controlled analgesia delivery system for 24 hours, followed by oral hydrocodone for 3 days. MEASUREMENTS AND MAIN RESULTS: The opioid consumption was recorded for 4 days postoperatively. Pain scores were measured at 4 to 8-hour intervals using 100 mm visual analog scales. There was no difference in either the opioid analgesic requirements or the pain scores between the three study groups. CONCLUSIONS: Wound infiltration, either preincision or postincision, had no clinically significant effect on the pain scores or analgesic requirements following abdominal hysterectomy.

The peri-operative management of atrial fibrillation.

Atrial fibrillation is a common arrhythmia frequently seen in surgical patients. The onset of new atrial fibrillation during the peri-operative period is less common. There are many possible precipitating factors, although volatile agents themselves may have an antifibrillatory action. The management of atrial fibrillation includes removal of any precipitating factors and treatment of the arrhythmia itself. Immediate management of acute-onset atrial fibrillation is usually direct current cardioversion. Alternatively, anti-arrhythmic drugs can be used to achieve cardioversion. In patients with rapid, chronic atrial fibrillation or those refractory to cardioversion, priority is given to control of the ventricular rate. Thrombo-embolism is a significant risk if atrial fibrillation is paroxysmal or persists for more than 48 h.

Prevention of pain on injection of propofol: a comparison of lidocaine with alfentanil.

We undertook a randomized, placebo-controlled, double-blind study to compare the use of alfentanil 1 mg and lidocaine 40 mg for the reduction of pain during injection of propofol. Eighty-nine patients were randomly allocated to one of three groups: Group L, lidocaine 40 mg added to 180 mg propofol; Group A, alfentanil 1 mg 30 s prior to propofol; or Group P, placebo (normal saline). The incidence of pain in the placebo group was 67%. Both treatment groups had a significantly lower incidence of pain than the placebo group (P < 0.002). There was no significant difference in the incidence of pain between the groups receiving lidocaine or alfentanil (13% and 24%, respectively). There was no significant difference in the induction dose of propofol between the groups. Fifty-two percent of patients who experienced pain at induction had recall of that pain in the recovery room. Alfentanil 1 mg and lidocaine 40 mg are both effective in reducing pain during injection of propofol.

Prevention of hypotension during spinal anesthesia: a comparison of intravascular administration of hetastarch versus lactated Ringer's solution.

This study was designed to compare the efficacy of 6% hetastarch to that of crystalloid administration in reducing the incidence and severity of hypotension during spinal anesthesia. Forty ASA grade I patients scheduled for postpartum tubal ligations under spinal anesthesia were randomly allocated to receive either 500 mL of hetastarch solution or 1000 mL of lactated Ringer's solution prior to spinal anesthesia. Spinal anesthesia was managed identically in both groups by anesthesiologists who were unaware of the type of fluid administered. The incidence of hypotension was 11 of 21 (52%) in the lactated Ringer's solution group and 3 of 19 (16%) in the hetastarch group. The difference in the incidence of hypotension was significant (P < 0.05). The requirement of 5-mg bolus doses of ephedrine to maintain systolic arterial blood pressure > 75% of baseline was significantly greater in the lactated Ringer's group than in the hetastarch group (15 vs 4, P < 0.05). We conclude that an intravenous infusion of 500 mL of 6% hetastarch solution is more effective than 1000 mL lactated Ringer's solution in attenuating spinal anesthesia induced hypotension in women undergoing postpartum tubal ligation.

Tracheal intubation in a manikin: comparison of supine and left lateral positions.

Tracheal intubation in the left lateral position may be necessary in some circumstances. Using a manikin we demonstrated that anaesthetic trainees found tracheal intubation in the left lateral position was more difficult and took longer than in the supine position. However, the time to successful tracheal intubation decreased with practice, indicating the presence of a learning curve. We suggest that tracheal intubation in the left lateral position should become part of training in the management of the difficult airway.

Cervical spine movement during orotracheal intubation: comparison of the Belscope and Macintosh blades.

This study was designed to compare the degree of cervical spine movement during laryngoscopy and tracheal intubation using the Belscope and Macintosh laryngoscope blades. Twenty ASA 1 and 2 patients scheduled for elective surgery requiring tracheal intubation were studied. Following induction of anaesthesia and muscle relaxation, a neutral cross-table lateral cervical spine X ray was taken. Laryngoscopy was then performed in each patient using both the Belscope and Macintosh blades. After visualisation of the vocal cords and tracheal intubation the cervical spine X ray was repeated. Movement of the cervical spine was evaluated by tracing bony landmarks on each film and then superimposing the neutral and intubating films. We were unable to demonstrate a difference in the amount of cervical spine movement comparing the two blades. Using the Belscope blade, intubation took longer (median 18 s) than the Macintosh blade (median 12 s, p < 0.01) and was unsuccessful in two patients despite adequate visualisation of the vocal cords.

Supraventricular tachycardia in a parturient under spinal anesthesia.

BACKGROUND AND METHODS: A 30-year-old woman with a history of palpitations was admitted for a repeat cesarean delivery at 41 weeks' gestation. Spinal anesthesia was administered. RESULTS: Supraventricular tachycardia and hypotension developed in the patient and were treated with boluses of ephedrine and phenylephrine. CONCLUSION: Phenylephrine may be used successfully for the treatment of SVT that results in hypotension under spinal anesthesia, and it may have advantages over ephedrine.

A survey of obstetric patients who refuse regional anaesthesia.

One hundred obstetric patients presenting for elective surgery who had refused regional anaesthesia were interviewed just prior to entering the operating room. In each case, the reason for refusing a regional technique was recorded. The most frequent reasons given were fear of backache (33%) and fear of the needle (28%). Anaesthetists should be aware of patients' concerns and be able to discuss the relevant issues.

EMLA cream effectively reduces the pain of spinal needle insertion.

BACKGROUND AND OBJECTIVE: EMLA cream is an effective topical anesthetic, which is commonly used for analgesia during venous cannulation in the pediatric population. This study was designed to compare the efficacy of EMLA cream with that of infiltration with lidocaine in relieving the pain associated with administration of spinal anesthesia. METHODS: The patient population consisted of 41 ASA status I and II women scheduled for postpartum tubal ligation. Spinal anesthesia was administered with a 25-gauge spinal needle via a 20-gauge introducer. The patients were randomly allocated to receive either EMLA cream for a minimum of 30 minutes or infiltration with 3 mL of 1% lidocaine prior to spinal needle insertion. Pain during spinal needle insertion was assessed immediately after each procedure by a 10-cm visual analog scale. RESULTS: Pain scores were significantly lower in the EMLA group (mean, 1.5) than in the lidocaine group (mean, 3.52) (P < .001). The number of patients satisfied with the method of analgesia was significantly higher in the EMLA than in the lidocaine group (90% vs 55%, P < .05). CONCLUSION: EMLA cream is an effective alternative to lidocaine infiltration for analgesia during the administration of spinal anesthesia when using a 25-gauge spinal needle via a 20-gauge introducer. Application of EMLA cream for at least 30 minutes prior to spinal needle insertion is adequate to provide good analgesia during needle insertion.

Tracheal tube cuff inflation as an aid to blind nasotracheal intubation.

We have assessed the efficacy of tracheal tube cuff inflation in the oropharynx as an aid to blind nasotracheal intubation in 20 ASA I and II patients undergoing elective oral surgery. The trachea was intubated once using the technique of tracheal tube cuff inflation in the oropharynx and once keeping the tracheal tube cuff deflated throughout the manoeuvre. With the cuff deflated, intubation was successful in nine of 20 (45%) patients; in eight of 20 (40%) it was successful on the first attempt. With the tracheal tube cuff inflated, intubation was successful in 19 of 20 patients (95%), 15 of 20 (75%) of these on the first attempt. The success rates were significantly different (P < 0.01). Times to intubate were not significantly different (P > 0.05). We conclude that, in normal patients, tracheal tube cuff inflation in the oropharynx increases the success rate of blind nasotracheal intubation.

Use of percutaneous electrical nerve stimulation (PENS) in the short-term management of headache.

OBJECTIVE: To evaluate the short-term effects of percutaneous electrical nerve stimulation (PENS) in the management of three types of chronic headache. BACKGROUND: Traditional electroanalgesic therapies have been reported to be effective in the management of acute headache symptoms. However, no controlled studies have been performed in patients with chronic headache. METHODS: Thirty patients with either tension headache, migraine, or posttraumatic headache symptoms of at least 6 months' duration were randomized to receive PENS (needles with electricity) or "needles alone" according to a crossover study design. All treatments were administered for 30 minutes, three times a week for 2 consecutive weeks with 1 week off between the two different treatments. For the PENS treatments, an alternating electrical stimulation frequency of 15 and 30 Hz was used. Pain, activity, and sleep scores were assessed using a 10-cm visual analog scale, with 0 corresponding to the best and 10 to the worst, during the 48-hour period prior to the beginning of the two treatments, immediately before and after each treatment session, and 48 hours after completing each treatment modality. RESULTS: Compared with the needles alone, PENS therapy was significantly more effective in decreasing the overall VAS pain scores for tension-type headache, migraine and posttraumatic headache (58%, 59%, and 52% versus 20%, 15%, and 20%, respectively). Similarly, PENS therapy produced greater improvement in the patients' physical activity (41% to 58% for PENS versus 11% to 21% for needles only) and quality of sleep (41% to 48% for PENS versus 12% to 20% for needles only). However, there were no differences in the pattern of the response to PENS therapy among the three headache groups. CONCLUSIONS: Percutaneous electrical nerve stimulation appears to be a useful complementary therapy to analgesic and antimigraine drugs for the short-term management of headache. Interestingly, the analgesic response to PENS therapy appears to be independent of the origin of the headache symptoms.

Use of the laryngeal mask airway after oesophageal intubation.

We have compared insertion of a tracheal tube and laryngeal mask airway (LMA) both with and without the presence of a tube in the oesophagus in 20 ASA I and II patients undergoing elective laparoscopy. After induction of anaesthesia and neuromuscular block, we measured the times for an experienced anaesthetist to correctly position both an LMA and a tracheal tube with and without a tube in the oesophagus. The time to intubation was significantly less with the LMA than with the tracheal tube, both with and without an oesophageal tube in place (P < 0.05). We conclude that if a tracheal tube is placed unintentionally in the oesophagus, an LMA may be used subsequently to provide rapid and effective oxygenation of the patient.

Comparison of an ephedrine infusion with crystalloid administration for prevention of hypotension during spinal anesthesia.

This study was designed to compare the efficacy of an ephedrine infusion with crystalloid administration for reducing the incidence of hypotension during spinal anesthesia. Fifty-four ASA I patients scheduled for postpartum tubal ligations under spinal anesthesia were randomly allocated to receive either 15 mL/kg of crystalloid (crystalloid group) or an ephedrine infusion (infusion group). Spinal anesthesia was performed using 70-90 mg of hyperbaric 5% lidocaine. Patients in the infusion group immediately thereafter received an ephedrine infusion at a rate of 5 mg/min for the first 2 min and then 1 mg/min for the next 18 min. The incidence of hypotension was 15/27 (55%) in the crystalloid group and 6/27 (22%) in the infusion group (P < 0.05). There was no significant difference between the groups in relation to the level of anesthesia or maximal heart rate, and hypertension did not occur in either group. We conclude that a prophylactic ephedrine infusion is effective for minimizing and managing hypotension associated with spinal anesthesia and compares favorably with crystalloid administration in this patient population in terms of efficacy and incidence of side effects.