Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2000
Clinical TrialRapid tracheal intubation with large-dose rocuronium: a probability-based approach.
There are situations in anesthesia in which it may be desirable to achieve rapid tracheal intubation with perfect conditions, i.e., no coughing or straining. To determine the dose of rocuronium that gives a high probability of achieving perfect conditions for rapid (within 60 s) tracheal intubation, we administered a range of doses of rocuronium, some larger than used previously. Sixty adults, anesthetized with thiopental 4 mg/kg IV and alfentanil 10 microg/kg IV, received rocuronium 0.4 to 2.0 mg/kg IV. We used logistic regression to define the relationship of rocuronium dose to probability of achieving perfect intubation conditions. We estimated the doses giving 90% and 95% probability of achieving perfect intubation and used resampling to determine confidence limits for these estimates. Rocuronium 1.85 and 2.33 mg/kg gave, respectively, 90% and 95% probability of perfect intubation conditions. The confidence limits (5th and 95th percentile) for these estimates were 1.15 to 2.31 and 1.23 to 3.22 mg/kg, respectively. In conclusion, it is possible to achieve perfect intubation conditions with large doses of rocuronium, but the long duration of action and expense may limit the usefulness of the technique. ⋯ We found that it is possible to have a 90% probability of achieving perfect conditions for rapid tracheal intubation with large (up to 2.0 mg/kg) doses of rocuronium. These large doses of rocuronium may be useful in, for instance, head trauma or open globe injuries if succinylcholine is contraindicated.
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Anesthesia and analgesia · Jan 2000
Clinical TrialSequential changes of arterial oxygen tension in the supine position during one-lung ventilation.
To investigate how surgical positions affect the severity and progress of hypoxemia during one-lung ventilation (OLV), we studied 33 adult patients undergoing right thoracotomy with left OLV. The patients were divided into three groups according to the positions during surgery as follows: the supine position (SP) group (n = 11), the left semilateral decubitus position (LSD) group (n = 9), and the left lateral decubitus position (LLD) group (n = 13). Analysis of arterial blood gases was sequentially determined every 5 min for 30 min during OLV (fractional ratio of inspiratory oxygen = 1.0) in each position. OLV was promptly terminated and switched to bi-lung ventilation if Spo2 declined to 90%. Pao2 progressively decreased with time in all three groups (P < 0.01). The incidence of termination of OLV within 30 min was higher in the SP group (82%), compared with that in the LSD (11%) and LLD (8%) groups (P < 0.01). Final Pao2 (65+/-12 mm Hg, mean +/- SD, P < 0.01 versus LLD, P < 0.05 versus LSD) and SaO2 (91%+/-4%, P < 0.01 versus LLD and LSD) at the termination of OLV in the SP group were the lowest. There was no difference between these values in the LSD and LLD groups (128+/-54 mm Hg, 96%+/-2%, and 167+/-69 mm Hg, 97%+/-4%, respectively) 30 min after the start of OLV. The time for Pao2 to decrease to 200 mm Hg calculated from each regression curve was 354 s in the SP group, 583 s in the LSD group, and 798 s in the LLD group. The time for Pao2 to decline to 100 mm Hg was 794 s in the SP group. In the regression curves of the LSD and LLD groups, the Pao2 did not decrease to 100 mm Hg. Heart rate was slow at baseline in the SP group (P < 0.05 versus LSD), but other hemodynamic variables did not differ among the three groups throughout this study. The LSD was as effective as the LLD in avoiding life-threatening hypoxemia during OLV. ⋯ Close observation and prompt counteractions including termination of one-lung ventilation (OLV) are crucial for patients under OLV in the supine position, because life-threatening hypoxemia frequently occurs approximately 10 min after starting OLV, even under 100% oxygen inhalation. The left semilateral decubitus position was as effective as the left lateral decubitus position in avoiding life-threatening hypoxemia during OLV.
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Anesthesia and analgesia · Jan 2000
Clinical TrialPredictors of recommendation and acceptance of intrapartum epidural analgesia.
We conducted this prospective study to characterize the obstetric and sociodemographic variables that predict physicians' recommendations and patients' acceptance of intrapartum epidural analgesia. The study population consisted of 447 consecutive, low-risk parturients in early active labor. Epidural analgesia was recommended to 393 patients (87.9%), however only 164 (41.7%) consented to receive it. A multiple logistic regression analysis demonstrated that the severity of pain, as assessed by the medical staff (odds ratio [OR] = 1.5, 95% confidence interval [CI] 1.13, 1.93), low parity (OR = 0.57, 95% CI 0.44, 0.74), and low maternal age (OR = 0.89, 95% CI 0.79, 0.99) were significant factors affecting recommendations of epidural analgesia. In a multivariate analysis, severity of subjective pain (OR = 1.39, 95% CI 1.16, 1.68), low parity (OR = 0.80, 95% CI 0.73, 0.99), high education (OR = 90.09, 95% CI 27.02,257.06), and the patients' being secular compared with religious (OR = 2.14, 95% CI 1.08,4.21) were found to be independent predictors of acceptance of epidural analgesia. There are differences between patients offered and those not offered epidural analgesia and between parturients who accept and those who do not accept this analgesia. ⋯ We studied the factors that influence the recommendation of epidural analgesia by obstetricians, as well as its acceptance by the laboring patients at a university hospital in Israel. Epidural analgesia was recommended more often to low parity, younger women exhibiting more pain. Parturients who perceived greater pain were more secular, had low parity, and had a higher level of education were more likely to accept it.
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Anesthesia and analgesia · Jan 2000
Spinal coadministration of ketamine reduces the development of tolerance to visceral as well as somatic antinociception during spinal morphine infusion.
This study was designed to investigate the effects of ketamine, an N-methyl-D-aspartate receptor antagonist, on the development of tolerance to morphine and morphine antinociception during intrathecal infusion. Two intrathecal catheters were implanted in the subarachnoid space in male rats under pentobarbital anesthesia. One catheter was used for the intrathecal infusion with the following solutions: morphine 1 microg x kg(-1) x hr(-1)(M1) and 5 microg x kg(-1) x hr(-1) (M5);ketamine 250 microg x kg(-1) x hr(-1) (K250); morphine plus ketamine, 1 microg x kg(-1) x hr(-1) plus 250 microg x kg(-1) x hr(-1) (M1 + K250) and 5 microg x kg(-1) x hr(-1) + 250 microg x kg(-1) x hr(-1) (M5 + K250); or saline. The other catheter was used for morphine challenge tests. The responses to noxious somatic and visceral stimuli were measured by tail flick (TF) and colorectal distension (CD) tests, respectively. Measurements were performed once a day for 7 days. Challenge tests with intrathecal morphine were performed to assess the magnitude of tolerance on Day 5 and Day 7. The antinociceptive effect was evaluated by using the percent of maximal possible effect (%MPE). Morphine infusion produced significant increases in %MPEs in TF and CD tests, while the saline and K250 infusions did not show any changes. The M1 + K250 infusion significantly increased the %MPEs in TF and CD tests, although the M1 and K250 infusions alone showed no changes. M5 + K250 enhanced the increases of %MPEs in TF and CD tests compared with the M5 infusion alone. In the challenge tests, the M1 + K250 infusion showed no significant decrease in %MPEs and TF and CD tests. The M5 + K250 infusion significantly inhibited those decreases in %MPEs, although the M5 infusion showed significant decreases in TF and CD tests. We concluded that ketamine attenuated the development of morphine tolerance to antinociceptive effects and increased the somatic and visceral antinociception of morphine. ⋯ Intrathecally coinfused ketamine attenuated morphine tolerance to somatic and visceral antinociception and increased morphine antinociception at the spinal level. These results suggest that a combination of morphine with ketamine may have an advantage in long-term use of opioids for controlling visceral as well as somatic pain.
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Anesthesia and analgesia · Jan 2000
Letter Case ReportsDual-plateau capnogram caused by cracked sample filter.