Anesthesia and analgesia
-
Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialThe effect of preoperative antiplatelet/anticoagulant prophylaxis on postoperative blood loss in cardiac surgery.
In this study we sought to determine whether preoperative treatment with antiplatelet and/or anticoagulant drugs influences postoperative blood loss after coronary artery bypass graft surgery. Although prophylactic treatment to prevent ischemic events preoperatively is often necessary, the treatment frequently continues until there may be a risk of increased bleeding (i.e., within 5-7 days before surgery). With patient consent, a preincision blood sample was collected prospectively from 93 adult subjects who presented randomly. They consisted of 3 groups regarding their primary preoperative regimen: 1) no preoperative treatment within the week before surgery; 2) platelet adenosine diphosphate (ADP) receptor antagonist; 3) ADP receptor antagonist plus IV heparin. Postoperative chest tube drainage (24 h) in the group that received ADP antagonist alone was more (P < 0.05) than either of the other groups: 503 +/- 56; 633 +/- 55; 439 +/- 29 mL (mean +/- SEM) for Groups 1, 2, and 3, respectively. Combined treatment with ADP antagonist plus heparin infusion appeared to prevent the increased blood loss with the ADP antagonist alone. Preincision and postoperative plasma fibrinogen concentrations were largest (P < 0.05) in the group that received the combination treatment; mean +/- SEM for groups 1, 2, and 3 preincision, 311 +/- 17, 366 +/- 16, and 423 +/- 18 mg/dL, and postoperatively, 229 +/- 16, 267 +/- 13, and 312 +/- 16 mg/dL. Postoperative fibrinogen showed strong dependence on preoperative fibrinogen in all groups (r = 0.576 to 0.825; P = 0.01 to 10(-6)). Prevention of the increased blood loss in the ADP receptor antagonist group by the addition of a heparin infusion may have been attributable to a conservation of coagulation factors, as evidenced by the increased plasma fibrinogen concentrations with combined prophylactic treatment. ⋯ The objective of this study was to determine whether preoperative treatment with antiplatelet and/or anticoagulant drugs influences the extent of blood loss in the 24-h period after cardiac surgery.
-
Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialSpinal 2-chloroprocaine: the effect of added dextrose.
Spinal 2-chloroprocaine is being investigated as an alternative short-acting spinal anesthetic to replace lidocaine for outpatient surgery. Adding dextrose increases the baricity of solutions and alters the characteristics of spinal anesthesia. In this study, we compared 2-chloroprocaine spinal anesthesia performed with or without the addition of dextrose (1.1%). Eight volunteers underwent 2 spinal anesthetics, receiving 40 mg 2-chloroprocaine (2 mL, 2%) with 0.25 mL saline with one and 0.25 mL 10% dextrose with the other in a double-blinded, randomized, balanced crossover manner. Pinprick anesthesia, tolerance to transcutaneous electrical stimulation, and tourniquet, motor strength measurements, and time to ambulation and void were assessed. Postvoid residual bladder volume was measured via ultrasound. Spinal anesthesia was successful in all subjects and regressed within 110 (80-110) min. There was no significant difference in peak height T4 (T7-C6), time to achieve peak block height (14 +/- 6 min), time for 2-segment regression (44 +/- 9 min), regression to L1 (66 +/- 12 min), tolerance of tourniquet (43 +/- 9 min), or return of motor function (81 +/- 14 min). Mean postvoid residual volume was larger with dextrose (74 +/- 67 mL versus 16 +/- 35 mL; P = 0.02). No subject reported signs of transient neurologic symptoms (TNS). In conclusion, spinal 2-chloroprocaine provides adequate potency with reliable regression, seemingly without TNS. Adding dextrose does not significantly alter spinal block characteristics but increases residual bladder dysfunction. Therefore, the addition of glucose to 2-chloroprocaine for spinal anesthesia is not necessary. ⋯ Spinal chloroprocaine provides adequate potency with reliable regression, seemingly without concerns of transient neurologic symptoms, and hence an appealing profile for outpatient surgery. The addition of dextrose does not alter peak block height or tolerance of thigh tourniquet, and increases the degree of residual bladder dysfunction.
-
Anesthesia and analgesia · Jan 2004
ReviewAre peripheral opioid antagonists the solution to opioid side effects?
Opioid medication is the mainstay of therapy for severe acute and chronic pain. Unfortunately, the side effects of these medications can affect patient comfort and safety, thus limiting their proven therapeutic potential. Whereas the main analgesic effects of opioids are centrally mediated, many of the common side effects are mediated via peripheral receptors. Novel peripheral opioid antagonists have been recently introduced that can block the peripheral actions of opioids without affecting centrally mediated analgesia. We review the clinical and experimental evidence of their efficacy in ameliorating opioid side effects and consider what further information might be useful in defining their role. ⋯ The major analgesic effects of opioid medication are mediated within the brain and spinal cord. Many of the side effects of opioids are caused by activation of receptors outside these areas. Recently developed peripherally restricted opioid antagonists have the ability to block many opioid side effects without affecting analgesia.
-
Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialAdministration of 100% oxygen before removal of the laryngeal mask airway does not affect postanesthetic arterial partial pressure of oxygen.
Breathing 100% oxygen at the end of general anesthesia has been shown to worsen postoperative pulmonary gas exchange when an endotracheal tube is used. Counter measures, such as high positive end-expiratory pressure or the vital-capacity maneuver, may limit this effect. Such strategies, however, may be impracticable, or even contraindicated, when the laryngeal mask airway (LMA) is used. Because of the vast differences in design between the LMA and endotracheal tube, we examined postanesthetic blood gas tensions in patients after emergence from anesthesia breathing oxygen via LMA. Sixty-four ASA physical status I-II patients undergoing general anesthesia for 60 min with LMA were randomly assigned to receive either 100% or 30% oxygen during emergence from anesthesia and removal of LMA. Postoperative blood gas measurements were taken at 30 and 60 min after removal of the LMA. At either measurement, patients treated with 100% oxygen essentially had the same arterial partial pressure of oxygen (60-min measurement: 83 +/- 8 versus 85 +/- 7 mm Hg [mean +/- SD], P = 0.14) as those treated with 30% oxygen. We conclude that breathing 100% oxygen at the end of general anesthesia does not worsen postoperative pulmonary gas exchange when an LMA is used. ⋯ The endotracheal tube and laryngeal mask airway are substantially different artificial airways used to ventilate the lungs of anesthetized patients. Breathing 100% oxygen before removing the endotracheal tube results in lung function defects. This study shows that oxygen breathing before removing the laryngeal mask airway has no effect on pulmonary function.
-
Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialThe pharmacokinetics and efficacy of ropivacaine continuous wound instillation after spine fusion surgery.
Because local anesthetic continuous wound instillation has not been evaluated after spine fusion surgery, we designed this study to determine whether this technique could enhance analgesia and improve patient outcome after posterior lumbar arthrodesis. Thirty-eight patients undergoing spine stabilization were randomly divided into two groups. The M group received a postoperative baseline IV infusion of morphine plus ketorolac for 24 h, and the R group received IV saline. In both groups, a multihole 16-gauge catheter was placed subcutaneously; in the R group, the wound was infiltrated with a solution of ropivacaine 0.5% 200 mg/40 mL, and infusion of ropivacaine 0.2% 5 mL/h was maintained for 55 h. In the M group, saline infusion was given at the same rate. Pain scores were taken at rest and on passive mobilization by nurses blinded to patient analgesic treatment. The total plasma ropivacaine concentration was evaluated. Pain scores and rescue medication requirements (diclofenac and tramadol) were significantly less in the R group than in the M group. Postoperative blood loss was less and the length of hospital stay was shorter in the R group. The ropivacaine peak total plasma concentration occurred at 24 h during infusion and was within safe limits; no toxic local anesthetic side effects were observed. These results suggest that wound infiltration and continuous instillation of ropivacaine 0.2% is effective for pain management after spine stabilization surgery. ⋯ Postoperative pain after lumbar arthrodesis is related to soft tissue and muscle dissection and to manipulations and removal at the operation site. By blocking noxious stimuli from the surgical area, infiltration and wound perfusion with ropivacaine were more effective in controlling pain than systemic analgesia.