Anesthesia and analgesia
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Anesthesia and analgesia · Mar 1997
Magnetic resonance imaging of cerebrospinal fluid leak and tamponade effect of blood patch in postdural puncture headache.
This prospective study examined the efficacy of magnetic resonance imaging (MRI) in visualizing cerebrospinal fluid (CSF) leak in patients with postdural puncture headache (PDPH) and determining the spread of the blood patch in the epidural space and the extent of tamponade on the thecal sac. After obtaining institutional review board approval, five patients with symptomatic PDPH after 3 days of failed conservative treatment were included in this study. MRI using proton density (PD) and T2-weighted imaging was performed on all patients and CSF flow studies were done on one patient. ⋯ The tamponade effect of the blood patch was observed on PD, T2-weighted, and CSF flow images. All patients experienced immediate resolution of their symptoms. This study suggests that using MRI, the site of the CSF leak, the tamponade effect of the blood patch, and its spread in the epidural space can be documented.
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Anesthesia and analgesia · Mar 1997
Peripherally administrated morphine attenuates capsaicin-induced mechanical hypersensitivity in humans.
We examined the hypothesis that peripheral morphine can modulate pain and hyperalgesia/allodynia in the human capsaicin model. Subcutaneous injections of 1 mL morphine (1 mg/mL) in one arm and of 1 mL 0.9% saline in the other arm were made prior to bilateral intradermal injections of 50 microL (6 mg/mL) capsaicin. All injections were made on the volar aspect of the arm. ⋯ Capsaicin injection resulted in spontaneous pain on the saline-injected side not significantly different from that on the morphine-injected side. However, capsaicin injections gave rise to significantly less pain evoked by mechanical stimuli, as well as to a significantly smaller area of mechanical hypersensitivity, on the morphine-injected side compared with the saline-injected side. These results suggest that morphine can modulate sensitization mechanisms involved in the development of capsaicin-induced mechanical hypersensitivity.
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Anesthesia and analgesia · Mar 1997
Reduced postoperative analgesic demand after inhaled anesthesia in comparison to combined epidural-inhaled anesthesia in patients undergoing abdominal surgery.
We studied the effect of epidural/general combination anesthesia, in comparison to inhaled anesthesia, on postoperative pain and analgesic consumption in patients undergoing upper abdominal surgery. Anesthesia was induced with propofol and maintained with enflurane in 70% N2O as necessary to maintain arterial blood pressure within 20% of baseline. Group I received bupivacaine 0.25% 0.2 mL/kg and sufentanil 1 microgram/kg 65 +/- 3 min before dermal incision and 0.1 mL/kg bupivacaine 0.25% + sufentanil 2 micrograms/mL (BS) every hour thereafter. ⋯ Inspiratory fraction of enflurane was lower (0.5% +/- 0.01% vs 1.6% +/- 0.04%; P < 0.001) in Group I compared with Group II. Cumulative postoperative consumption of PCEA BS was higher in Group I compared with Group II from the evening of POD 2 until the end of the study (301 +/- 19 mL vs 249 +/- 17 mL; P < 0.001), while pain intensities were comparable at all times. The intraoperative effects of combined BS and enflurane/N2O (inspiratory fraction [Fi] approximately 1 minimum alveolar anesthetic concentration [MAC]) did not preempt postoperative pain in contrast to enflurane/N2O anesthesia (Fi approximately 2.8 MAC).
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The incidence of difficulty in tracheal intubation in the presence of goiter was investigated. Data were collected in a series of 4742 consecutive adult patients undergoing general anesthesia. The prevalence of goiter was 6.8%. ⋯ There was no difference in probability of difficulty in tracheal intubation between patients who presented for thyroidectomy and patients with goiter estimated as a random finding. Statistical analysis revealed an increased risk of difficult intubation amongst goiter patients compared with patients with no evidence of any risk factor (6.8% vs 0.9%, P < 10(-8), relative risk = 7.4). We conclude that goiter, when accompanied by airway deformity, constitutes an aggravating factor for difficult intubation.
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Anesthesia and analgesia · Mar 1997
The relaxant effect of ketamine on guinea pig airway smooth muscle is epithelium-independent.
Airway epithelial cells and vascular endothelial cells modulate the tone of the underlying smooth muscle by releasing relaxing factors such as prostanoids and nitric oxide (NO). In the present study, we investigated whether the relaxant effect of ketamine depends on any of the epithelium-derived relaxing factors. Tracheae of female guinea pigs were cut spirally into strips (15 x 3 mm) and mounted in water-jacketed organ baths filled with Krebs-bicarbonate buffer aerated with a mixture of 95% O2 and 5% CO2 at 37 degrees C. ⋯ L-NAME did not influence the relaxant effect of ketamine on tracheae contracted by either histamine (the IC50 of ketamine = 1.6 +/- 0.05 x 10(-3) M in control strips and 1.6 +/- 0.05 x 10(-3) M in strips pretreated with L-NAME, P > 0.05) or carbachol (the IC50 of ketamine = 2.6 +/- 0.04 x 10(-4) M in control strips and 2.3 +/- 0.01 x 10(-4) M in trips pretreated with L-NAME, P > 0.05). These results indicate that neither the mechanical removal of the tracheal epithelium nor the blockade of the release of potent mediators from tracheal epithelial cells influence the relaxant effect of ketamine on guinea pig tracheal strips contracted by histamine or carbachol. We conclude that ketamine relaxes the airway smooth muscle by an epithelium-independent mechanism.