Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2004
Randomized Controlled Trial Comparative Study Clinical TrialIntrathecal midazolam II: combination with intrathecal fentanyl for labor pain.
Recent investigations have sought to improve intrathecal analgesia by combining opioids with other classes of analgesics. In this study we assessed the ability of intrathecal midazolam to increase the potency and duration of the analgesic effects of intrathecal fentanyl without causing adverse effects. Thirty parturients with cervical dilations 2-6 cm were randomized to receive either intrathecal midazolam 2 mg, fentanyl 10 micro g, or both combined to initiate analgesia. Pain scores were recorded before and at 5-min intervals for 30 min after the injection and then every 30 minutes until the patient requested further analgesia. The presence and severity of nausea, emesis, pruritus, headache, and sedation, in addition to arterial blood pressure, heart rate, respiratory rate, sensory changes to ice, motor impairment, cardiotocograph, and Apgar score were also recorded. The parturients were assessed after 2 days and 1 mo for neurologic impairment. Preinjection pain scores were unaltered by intrathecal midazolam alone and moderately decreased by fentanyl. Intrathecal midazolam increased the analgesic effect of fentanyl. No treatment altered cardiorespiratory variables or caused motor impairment. The addition of intrathecal midazolam to fentanyl did not increase the occurrence of any maternal adverse event or abnormalities on the cardiotocograph. We conclude that intrathecal midazolam enhanced the analgesic effect of fentanyl without increasing maternal or fetal adverse effects. ⋯ Treatment of labor pain with epidural injections of local anesthetic is complicated by decreases in arterial blood pressure and leg weakness. This study showed that a mixture of two drugs, fentanyl and midazolam, could provide powerful pain relief when the drugs were given together spinally without such side effects.
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Anesthesia and analgesia · Jun 2004
Comparative StudyA comparison of frontal and occipital bispectral index values obtained during neurosurgical procedures.
We placed bispectral index (BIS) sensors on the frontal and occipital areas of neurosurgical patients and compared BIS values obtained from both areas during propofol/fentanyl anesthesia. BIS showed a strong correlation between frontal and occipital montages (r(2) = 0.96; P = 0.03). It may be valid to measure BIS with the sensor on the occipital area if required during frontal neurosurgical procedures. ⋯ Bispectral values were positively correlated when recorded from frontal and occipital sensors in patients undergoing clipping of unruptured cerebral aneurysms while anesthetized with propofol and fentanyl.
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Anesthesia and analgesia · Jun 2004
A simple, fast, easy method to identify the evidence base in pain-relief research: validation of a computer search strategy used alone to identify quality randomized controlled trials.
Clinicians need a simple, fast, reliable, and inexpensive way of identifying the evidence base relevant to their clinical practice. It is often believed that the only way to identify all relevant evidence is to perform hand-searches of the literature to supplement computer searches; this is complex and labor intensive. However, most of quality randomized controlled trials cited in systematic reviews in pain medicine are listed in computer databases. We performed two studies to investigate the efficiency-in terms of sensitivity, specificity, and precision-of three computer search strategies: Optimally Sensitive Search Strategy, which is used by the Cochrane Collaboration; RCT.pt, a standard MEDLINE strategy; and DBRCT.af, which is a new single-line computer algorithm based on the assumption that double-blinded, randomized controlled trials would be indexed with "double-blind," "random," or variations of these terms in MEDLINE and EMBASE. DBRCT.af was found to be highly sensitive (97%) in identifying quality randomized controlled trials in pain medicine. The precision (ratio of randomized controlled trials to the number of nonrandomized trials identified) was 82%, and the specificity in excluding the nonrandomized controlled trials was 98%. We conclude that clinicians can now use DBRCT.af to update and conduct de novo systematic reviews in pain-relief research. ⋯ Quality evidence about what is good clinical practice in pain treatment is buried in the medical literature among large quantities of other information. This article describes how any clinician with access to the Internet can identify those quality studies reliably, quickly, and inexpensively.
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Anesthesia and analgesia · Jun 2004
Comparative StudyLung recruitment improves the efficiency of ventilation and gas exchange during one-lung ventilation anesthesia.
Atelectasis in the dependent lung during one-lung ventilation (OLV) impairs arterial oxygenation and increases dead space. We studied the effect of an alveolar recruitment strategy (ARS) on gas exchange and lung efficiency during OLV by using the single-breath test of CO(2) (SBT-CO(2)). Twelve patients undergoing thoracic surgery were studied at three points in time: (a) during two-lung ventilation and (b) during OLV before and (c) after an ARS. The ARS was applied selectively to the dependent lung and consisted of an increase in peak inspiratory pressure up to 40 cm H(2)O combined with a peak end-expiratory pressure level of 20 cm H(2)O for 10 consecutive breaths. The ARS took approximately 3 min. Arterial blood gases, SBT-CO(2), and metabolic and hemodynamic variables were recorded at the end of each study period. Arterial oxygenation and dead space were better during two-lung ventilation compared with OLV. PaO(2) increased during OLV after lung recruitment (244 +/- 89 mm Hg) when compared with OLV without recruitment (144 +/- 73 mm Hg; P < 0.001). The SBT-CO(2) analysis showed a significant decrease in dead-space variables and an increase in the variables related to the efficiency of ventilation during OLV after an ARS when compared with OLV alone. In conclusion, ARS improves gas exchange and ventilation efficiency during OLV. ⋯ In this article, we showed how a pulmonary ventilatory maneuver performed in the dependent lung during one-lung ventilation anesthesia improved arterial oxygenation and dead space.
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Anesthesia and analgesia · Jun 2004
Comparative StudyTreatment of uncontrolled hemorrhagic shock after liver trauma: fatal effects of fluid resuscitation versus improved outcome after vasopressin.
In a porcine model of uncontrolled hemorrhagic shock, we evaluated the effects of vasopressin versus an equal volume of saline placebo versus fluid resuscitation on hemodynamic variables and short-term survival. Twenty-one anesthetized pigs were subjected to severe liver injury. When mean arterial blood pressure was <20 mm Hg and heart rate decreased, pigs randomly received either vasopressin IV (0.4 U/kg; n = 7), an equal volume of saline placebo (n = 7), or fluid resuscitation (1000 mL each of lactated Ringer's solution and hetastarch; n = 7). Thirty minutes after intervention, surviving pigs were fluid resuscitated while bleeding was surgically controlled. Mean (+/- SEM) arterial blood pressure 5 min after the intervention was significantly (P < 0.05) higher after vasopressin than with saline placebo or fluid resuscitation (58 +/- 9 versus 7 +/- 3 versus 32 +/- 6 mm Hg, respectively). Vasopressin improved abdominal organ blood flow but did not cause further blood loss (vasopressin versus saline placebo versus fluid resuscitation 10 min after intervention, 1343 +/- 60 versus 1350 +/- 22 versus 2536 +/- 93 mL, respectively; P < 0.01). Seven of 7 vasopressin pigs survived until bleeding was controlled and 60 min thereafter, whereas 7 of 7 saline placebo and 7 of 7 fluid resuscitation pigs died (P < 0.01). We conclude that vasopressin, but not saline placebo or fluid resuscitation, significantly improves short-term survival during uncontrolled hemorrhagic shock. ⋯ Although IV fluid administration is the mainstay of nonsurgical management of trauma patients with uncontrolled hemorrhagic shock, the efficacy of this strategy has been discussed controversially. In this animal model of severe liver trauma with uncontrolled hemorrhagic shock, vasopressin, but not saline placebo or fluid resuscitation, improved short-term survival.