Propofol 2 mg/kg is superior to propofol 1 mg/kg for tracheal intubation in children during sevoflurane induction.

BACKGROUND: Propofol has been used to facilitate tracheal intubation within a short time of sevoflurane induction without a muscle relaxant in children. We compared as the primary outcome the incidence of excellent intubating conditions after 8% sevoflurane and propofol 1 or 2 mg/kg. METHODS: One hundred and four patients (2-7 years) were randomly assigned to receive propofol 1 mg/kg in group SP1 (n=53) or propofol 2 mg/kg in group SP2 (n=51) after inhalation induction using sevoflurane 8% in oxygen. Forty-five seconds after propofol and controlled ventilation, intubating conditions were assessed using a four-point scoring system based on ease of laryngoscopy, vocal cords position, coughing, jaw relaxation and limb movement. Heart rate and systolic blood pressure were measured as baseline, after sevoflurane induction, propofol, intubation and at 2 and 5 min following intubation. RESULTS: Three patients in group SP1 were excluded from analysis. Time from sevoflurane induction to intubation (248.9±71.3 s in group SP1 vs. 230.9±61.3 s in group SP2) and endtidal sevoflurane before intubation (5.6±1.6% in group SP1 vs. 5.2±1.5% in group SP2) did not differ between the two groups. The incidence of excellent intubating conditions was significantly higher in group SP2 compared with group SP1 [47/51 (92%) vs. 28/50 (56%)]. The incidence of acceptable intubating conditions was significantly higher in group SP2 compared with group SP1 [48/51 (94%) vs. 35/50 (70%)]. No hemodynamic difference was noted at any time point between the two groups. CONCLUSION: Propofol 2 mg/kg during 8% sevoflurane induction resulted in a higher proportion of excellent intubating conditions compared with propofol 1 mg/kg.

Effect of suxamethonium vs rocuronium on onset of oxygen desaturation during apnoea following rapid sequence induction.

This study investigates the effect of suxamethonium vs rocuronium on the onset of haemoglobin desaturation during apnoea, following rapid sequence induction of anaesthesia. Sixty patients were randomly allocated to one of three groups. Anaesthesia was induced with lidocaine 1.5 mg.kg(-1), fentanyl 2 microg.kg(-1) and propofol 2 mg.kg(-1), followed by either rocuronium 1 mg.kg(-1) (Group R) or suxamethonium 1.5 mg.kg(-1) (Group S). The third group received propofol 2 mg.kg(-1) and suxamethonium 1.5 mg.kg(-1) only (Group SO). The median (IQR [range]) time to reach S(p)O(2) of 95% was significantly shorter in Group S (358 (311-373 [245-430]) s) [corrected] than in Group R (378 (370-393 [366-420]) s; p = 0.003), and shorter in Group SO (242 (225-258 [189-270]) s) [corrected] than in both Group R (p < 0.001) and Group S (p < 0.001). When suxamethonium is administered for rapid sequence induction of anaesthesia, a faster onset of oxygen desaturation is observed during the subsequent apnoea compared with rocuronium. However, time to desaturation is prolonged whenever lidocaine and fentanyl precede suxamethonium.

Comparison of three doses of epidural fentanyl followed by bupivacaine and fentanyl for labor analgesia.

BACKGROUND: Epidural fentanyl 100 microg after lidocaine-epinephrine test dose has been shown to provide adequate analgesia in early labor. This investigation determines the effect of three different bolus doses of epidural fentanyl on duration and quality of analgesia during early first stage of labor. METHODS: In this prospective, double-blind study, 103 laboring nulliparous at cervical dilation <5 cm were enrolled. After an epidural test dose of lidocaine (60 mg) with epinephrine (15 microg), parturients received, randomly, bolus of epidural fentanyl 50, 75, or 100 microg, followed by a continuous infusion of epidural bupivacaine 0.0625% and fentanyl 3 microg/ml at a rate of 10 ml/h. Pain scores and maternal sedation, pruritus, nausea, and vomiting were recorded 10, 20, and 30 min after fentanyl, and every 30 min thereafter until first request for additional analgesia. RESULTS: Adequate analgesia was achieved in 87% (28/32), 94% (35/38), and 94% (31/33) in the fentanyl 50, 75, and 100 microg groups within 20 min. Mean duration of analgesia before re-dosing was significantly longer in fentanyl 100 and 75 microg groups (185.6+/-82.9 and 188.5+/-82.2 min, respectively) as compared with fentanyl 50 microg group (133.6+/-46.2 min, P<0.016). There was no difference in the incidence of maternal side effects or neonatal Apgar scores among the three groups. CONCLUSION: After a test dose of lidocaine-epinephrine, the three epidural fentanyl doses produced similar effective labor analgesia. However, epidural fentanyl 75 microg followed by epidural infusion of dilute bupivacaine and fentanyl produced longer duration of analgesia than fentanyl 50 microg followed by the same infusion, with no further prolongation when the dose of fentanyl was increased up to 100 microg.

Supplementation of pre-oxygenation in morbidly obese patients using nasopharyngeal oxygen insufflation.

During apnoea following induction of anaesthesia, morbidly obese patients may suffer a rapid decrease in oxygen saturation. This study compares pre-oxygenation alone with pre-oxygenation followed by nasopharyngeal oxygen insufflation on the onset of desaturation occurring during the subsequent apnoea. A randomised controlled trial was performed in 34 morbidly obese patients undergoing gastric bypass or gastric band surgery. Seventeen patients received nasopharyngeal oxygen supplementation following pre-oxygenation (Study group, body mass index = 41.8 (6.9) kg.m(-2)), and the other 17 patients received pre-oxygenation alone (Control group, body mass index = 42.7 (5.4) kg.m(-2)). Time from the onset of apnoea until S(p)o(2) fell to 95% was compared between the two groups with a cut-off of 4 min. In the control group, the S(p)o(2) fell from 100% to 95% during the subsequent apnoea in 145 (27) s, with a significantly negative correlation (r(2) = 0.66, p < 0.05) between the time to desaturation to 95% and the body mass index. In the study group, the S(p)o(2) was maintained in 16 of 17 patients at 100% for 4 min when apnoea was terminated. In conclusion, nasopharyngeal oxygen insufflation following pre-oxygenation in morbidly obese patients delays the onset of oxyhaemoglobin desaturation during the subsequent apnoea.

Haloperidol vs. ondansetron for the prevention of postoperative nausea and vomiting following gynaecological surgery.

BACKGROUND AND OBJECTIVE: Ondansetron is widely used for the prophylaxis of postoperative nausea and vomiting, while haloperidol is an antiemetic that lacks recent data on efficacy and adverse effects. METHODS: In this prospective, randomized, double-blinded study involving 93 females undergoing gynaecological procedures under general anaesthesia, we compared the efficacy and adverse effects of prophylactic haloperidol 1 mg intravenous and ondansetron 4 mg intravenous vs. placebo. RESULTS: During the overall observation period (0-24 h), in the haloperidol, ondansetron and placebo groups respectively, the incidence of nausea and/or vomiting was 40.7% (11/27), 48.2% (13/27) and 55.5% (15/27), and the need of rescue antiemetics was 22.2% (6/27), 44.4% (12/27) and 40.7% (11/27), with P values >0.05 among the three groups. During the early observation period (0-2 h), in the haloperidol, ondansetron and placebo groups respectively, the incidence of nausea and/or vomiting was 13.7% (4/29), 26.6% (8/30) and 43% (13/30), and the need for rescue antiemetics was 6.8% (2/29), 26.6% (8/30) and 36.6% (11/30). Between haloperidol and placebo groups, the P value was 0.04 for nausea and/or vomiting, and was 0.01 for rescue antiemetics, in addition to lower nausea scores (P = 0.03). During the late observation period (2-24 h), no significant difference was shown among the three groups. CONCLUSION: The prophylactic administration of 1 mg intravenous haloperidol or 4 mg ondansetron, in female patients undergoing gynaecological surgery, did not improve the overall incidence of nausea and/or vomiting vs. placebo. However, haloperidol 1 mg proved to be an effective antiemetic in the early observation period without significant adverse effects.

Nasopharyngeal oxygen insufflation following pre-oxygenation using the four deep breath technique.

This paper evaluates the effectiveness of nasopharyngeal oxygen insufflation following preoxygenation using the four deep breath technique within 30 s, on the onset of haemoglobin desaturation during the subsequent apnoea. Thirty ASA I or II patients were randomly allocated to one of two groups. In the study group (n = 15), pre-oxygenation was followed by insufflation of oxygen at a flow of 5 l.min(-1) via a nasopharyngeal catheter commenced at the onset of apnoea. In the control group, pre-oxygenation was not followed by nasopharyngeal oxygen insufflation (n = 15). In the control group, SpO2 fell to 95% within a mean (SD) apnoea time of 3.65 (1.15) min, whereas in the study group, SpO2 was maintained in all patients at 100% throughout the 6 min of apnoea, at which point apnoea was terminated and positive pressure ventilation commenced. We conclude that nasopharyngeal oxygen insufflation following pre-oxygenation using the four deep breath technique can delay the onset of haemoglobin desaturation for a significant period of time during the subsequent apnoea.

Low frequency jet ventilation for stent insertion in a patient with tracheal stenosis.

PURPOSE: Evaluate oxygen jet ventilation in a patient with tracheal stenosis undergoing stent insertion. CLINICAL FEATURES: Manual intermittent low frequency oxygen jet ventilation was used during general anesthesia for fibreoptic bronchoscopy and stent insertion in a patient with tracheal stenosis. Oxygen jets were delivered via a Sander's injector adapted to the proximal end of the endotracheal tube on one side, and open to room air on the other side. Adequate oxygenation and carbon dioxide removal were ensured throughout the procedure. CONCLUSION: Low frequency jet ventilation in a patient with tracheal stenosis provided adequate ventilation as well as a non- obstructed field during fibreoptic bronchoscopy and stent insertion.

Neuromuscular interaction of sevoflurane--cisatracurium in a myasthenic patient.

PURPOSE: To describe the influence of sevoflurane anesthesia on cisatracurium neuromuscular block in a myasthenic patient undergoing thymectomy. CLINICAL FEATURES: A myasthenic patient (Osserman IIB) was managed for one year before surgery with 60 mg pyridostigmine qid, 50 mg immuran tid and 30 mg prednisone therapy. Pyridostigmine was interrupted three months before surgery, and five sessions of plasmapheresis were done within 13 days before surgery. The neuromuscular response was monitored by Datex electromyographic response to train-of-four stimulation of the ulnar nerve. Sevoflurane 4% decreased the T1/C ratio by 20%. Administration of 0.025 mg x kg(-1) cisatracurium, during sevoflurane anesthesia, was followed by complete neuromuscular block for 45 min. Discontinuation of sevoflurane resulted, after 10 min, in recovery of the T which reached T1/C ratio of 50% after 30 min. CONCLUSION: The marked sensitivity of this myasthenic patient to 0.5 x ED95 of cisatracurium can be attributed to potentiation of cisatracurium neuromuscular block by sevoflurane, as evidenced by the reappearance of the first twitch of the train-of-four response 10 min after sevoflurane was discontinued.

Preoxygenation: comparison of maximal breathing and tidal volume breathing techniques.

BACKGROUND: Preoxygenation with tidal volume breathing for 3-5 min is recommended by Hamilton and Eastwood. This report compares tidal volume preoxygenation technique with deep breathing techniques for 30-60 s. METHODS: The study was conducted in two parts on patients undergoing elective coronary bypass grafting. In the first group (n = 32), each patient underwent all of the following preoxygenation techniques: the traditional technique consisting of 3 min of tidal volume breathing at an oxygen flow of 5 l/min; four deep breaths within 30 s at oxygen flows of 5 l/min, 10 l/min, and 20 l/min; and eight deep breaths within 60 s at an oxygen flow of 10 l/min. The mean arterial oxygen tensions after each technique were measured and compared. In the second group (n = 24), patients underwent one of the following techniques of preoxygenation: the traditional technique (n = 8), four deep breaths (n = 8), and eight deep breaths (n = 8). Apnea was then induced, and the mean times of hemoglobin desaturation from 100 to 99, 98, 97, 96, and 95% were determined. RESULTS: In the first group of patients, the mean arterial oxygen tension following the tidal breathing technique was 392+/-72 mm Hg. This was significantly higher (P<0.05) than the values obtained following the four deep breath technique at oxygen flows of 5 l/min (256+/-73 mm Hg), 10 l/min (286+/-69 mm Hg), and 20 l/min (316+/-67 mm Hg). In contrast, the technique of eight deep breaths resulted in a mean arterial oxygen tension of 369+/-69 mm Hg, which was not significantly different from the value achieved by the traditional technique. In the second group of patients, apnea following different techniques of preoxygenation was associated with a slower hemoglobin desaturation in the eight-deep-breaths technique as compared with both the traditional and the four-deep-breaths techniques. CONCLUSION: Rapid preoxygenation with the eight deep breaths within 60 s can be used as an alternative to the traditional 3-min technique.

Transient atrioventricular block after release of aortic cross-clamp.

To determine the incidence of atrioventricular (A-V) block, 86 patients, aged 58.9 +/- 10.4 yr, undergoing elective coronary artery bypass grafting (CABG) during aortic cross-clamping (ACC) and cold potassium cardioplegia were investigated. The incidence and duration of complete A-V block after release of the aortic cross-clamp was monitored. Twenty-four percent of the patients developed complete A-V block that required temporary pacing for a mean time of 66 +/- 39 min. The volume of cardioplegia used was not significantly different between the patients who developed A-V block and the patients who had no block. The serum potassium level at the time of release of the aortic cross-clamp was within the normal range in both groups. Six factors were correlated with the development of A-V block: old age, preparation by a combination of beta-adrenergic blockers and calcium channel blockers, preoperative bradycardia, the number of vessels grafted, as well as the duration of ACC. Also, the serum potassium level at the time of release of the aortic cross-clamp was significantly higher in the patients who developed A-V block. The high incidence of A-V block in elderly patients undergoing multiple coronary vessel grafting during a prolonged ACC time suggests that suboptimal myocardial preservation may be the main predisposing factor.

Intravascular administration of polymerized gelatin versus isotonic saline for prevention of spinal-induced hypotension.

This report tests the hypothesis that intravascular prehydration with 3% gelatin in electrolyte solution maintains arterial blood pressure after spinal anesthesia better than with an equal volume of isotonic saline solution. Thirty-four patients undergoing elective transurethral resection of the prostate were allocated randomly to receive either 7 mL/kg of isotonic saline 0.9% (17 patients) or 7 mL/kg of 3% gelatin in electrolyte solution (17 patients) before spinal anesthesia. There was a significant increase in central venous pressure in the gelatin group without any significant change in the isotonic saline group. After spinal anesthesia, the mean systolic blood pressure significantly decreased in both groups; however, the incidence of systolic blood pressure greater than 75% of control value was higher in the gelatin group (15/17) than in the normal saline group (9/17). Also, the mean dose of phenylephrine required to maintain arterial blood pressure > 75% of the baseline value was significantly larger in the normal saline group than in the gelatin group. We conclude that prophylactic administration of gelatin is more effective than saline in attenuating spinal anesthesia-induced hypotension.

Effect of alpha-stat versus pH-stat strategy on oxyhemoglobin dissociation and whole-body oxygen consumption during hypothermic cardiopulmonary bypass.

To determine whether alpha-stat or pH-stat strategy should be used, 20 patients undergoing coronary artery bypass grafting during moderate hypothermic hemodilutional cardiopulmonary bypass were studied. The carbon dioxide management during bypass was randomly done according to alpha-stat strategy in 10 patients (i.e., temperature-uncorrected PaCO2 was kept near 40 mm Hg and uncorrected pHa was kept at about 7.4) and according to pH-stat strategy in the other 10 patients (i.e., temperature-corrected PaCO2 was kept near 40 mm Hg and uncorrected pHa was kept at about 7.4). In both groups, when the central venous temperature was stable at 26.5 +/- 2.5 degrees C, the perfusion flow was altered sequentially from 2.4 to 1.8 and 1.2 L.min-1.m-2. The mixed venous oxyhemoglobin saturation at the different perfusion flows was monitored by the Oxy-Stat meter and was correlated with the corresponding mixed venous oxygen tension to construct an oxyhemoglobin dissociation curve. Also, the whole-body oxygen consumption at the different perfusion flows was computed. The whole-body oxygen consumption and the oxyhemoglobin dissociation were not significantly different between the alpha-stat and the pH-stat groups. In both groups, the dissociation curve is shifted to the left, but the oxygen consumption per unit time does not significantly change despite decreasing the perfusion flow from 2.4 to 1.2 L.min-1.m-2. The results suggest that oxygen delivery is not impaired during moderate hypothermic cardiopulmonary bypass independent of whether alpha-stat or pH-stat strategy is used.