摘要:

This study evaluates the efficacy and side effects of a low dose of epidural morphine combined with clonidine for postoperative pain relief after lumbar disc surgery. In 36 of 51 patients who accepted the procedure, an epidural catheter was inserted (L1-L2level). General anesthesia was induced with propofol and sufentanil, and maintained with sevoflurane in O2/N2O. After emergence from anesthesia, epidural analgesia was initiated according to two randomly assigned protocols: 1 mg of morphine with 75 &mgr;g of clonidine (Group M) or 12.5 mg of bupivacaine with 75 &mgr;g of clonidine (Group B), in 10 mL saline. Piritramide was administered during the first postoperative 24 hours using a patient-controlled analgesia device (PCA). The following parameters were recorded: piritramide consumption during the first 24 hours; pain at rest during the first postoperative hours (D0), during the first night (D1), and during the first mobilization; [visual analogue scale (VAS)]; and the occurrence of drowsiness, motor blockade, respiratory depression, nausea, vomiting, itching, micturition problems, and bladder catheterization during D0 and D1. Epidural administration of morphine-clonidine significantly improved postoperative pain relief and reduced piritramide consumption as compared to epidural bupivacaine-clonidine. Side effects did not differ between groups except for a higher incidence of micturition problems in Group M during D1. The occurrence of bladder catheterization was not significantly higher in that group. We conclude that a low dose of epidural morphine combined with clonidine offers a better postoperative analgesia than does bupivacaine-clonidine. The excellent analgesic conditions were obtained at the expense of a higher incidence of difficulties in initiating micturition.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Bispectral Index (BIS) has been marketed as a measure of the hypnotic component of anesthesia and is recommended as a guide for the administration of hypnotic drugs during anesthesia. BIS values between 40 and 60 are recommended for surgery under general anesthesia. This study investigates whether a BIS baseline between 50 and 60 prevents awareness reaction to endotracheal intubation. After approval by the university's Ethics Committee, 20 consenting patients were enrolled in the study. Midazolam (0.1 mg/kg PO) was given 30 minutes before induction. Anesthesia was induced with alfentanil (10 mcg/kg, followed by 2 mcg/kg−/min−) and propofol infusion was adjusted to a BIS target level between 50 and 60. Propofol infusion rate was maintained constant for 5 minutes with constant BIS. Prior to intubation, patients were tested in one-minute intervals for awareness using Tunstall's isolated forearm technique. Three minutes after endotracheal intubation, the study period ended and surgery was performed. After intubation, 8 of 20 patients showed an awareness reaction, squeezing the investigator's hand in response to a command. No patient had recall. Comparison of patients with and without awareness reaction revealed no differences in BIS before or after intubation. This study shows that a BIS value between 50 and 60 prior to intubation is inadequate to prevent an awareness reaction to endotracheal intubation during propofol/alfentanil anesthesia. Because BIS cannot differentiate between patients with and without awareness reaction, its value as a monitor for awareness and a measurement of the hypnotic component of anesthesia must be questioned.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The purpose of this study was to investigate the effect of different concentrations of desflurane on jugular bulb gases and jugular bulb pressure (JBP) and to determine an optimal concentration of desflurane in neurosurgical patients with supratentorial tumor. Twenty-two patients were anesthetized with desflurane in oxygen. Radial arterial and jugular bulb catheters were inserted for blood gas sampling and direct blood pressure measurement after anesthesia. Mean arterial blood pressure (MAP), heart rate (HR), and JBP were monitored continuously. Arterial and jugular bulb blood gases were measured at 0.7 minimum alveolar contraction (MAC) (4.2%), 1.0 MAC (6%), and 1.3 MAC (7.8%) of desflurane randomly after a 30-minute stabilization period, respectively. Jugular bulb oxygen saturation (SJO2) significantly increased and cerebral arteriojugular difference of oxygen content (AJDO2) and oxygen extraction ratio (O2ER) significantly decreased from 0.7 MAC to 1.0 MAC of desflurane, but there was no further increase in SJO2nor further decreases in AJDO2and O2ER at 1.3 MAC compared with 1.0 MAC desflurane. There was a significant dose-related decrease in MAP from 0.7 MAC to 1.3 MAC of desflurane, but JBP did not change significantly. No significant change in hour was observed in the study. It is concluded that 1.0 MAC is a suitable concentration of desflurane in neurosurgery with an improved balance between cerebral oxygen supply and demand.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Cerebral swelling and herniation pose serious surgical obstacles during craniotomy for space-occupying lesions. Positioning patients head-up has been shown previously to reduce intracranial pressure (ICP) in neurotraumatized patients, but has not been investigated during intracranial surgery. The current study examined the effects of 10-deg reverse Trendelenburg position (RTP) on ICP and cerebral perfusion pressure (CPP). Forty adult patients subjected to craniotomy for supratentorial tumors were given standardized propofol–fentanyl–cisatracurium general anesthesia and were moderately hyperventilated. In 26 of 40 patients with expected poor clinical outcome, an additional catheter was placed in the internal jugular bulb to determine internal jugular bulb pressure (JBP). ICP was determined by subdural measurement using a 22-gauge needle advanced through the dura after removal of the bone flap. ICP was referenced to the level of the dural incision. ICP, mean arterial blood pressure, and CPP were compared with repeat measurements 1 minute after RTP. The tension of the dura was graded qualitatively by the surgeon by digital palpation and was compared to post-RTP. ICP decreased from 9.5 mm Hg to 6.0 mm Hg (P< .001; all values are median) within 1 minute after 10-deg RTP. Mean arterial blood pressure decreased from 82.0 mm Hg to 78.5 mm Hg (P< .001). CPP was unchanged (70.5 mm Hg versus 71 mm Hg after RTP), whereas JBP decreased from 8 mm Hg to 4 mm Hg (P< .001). High initial ICP was correlated to the greatest magnitude of decrease in ICP. No significant correlation was found between change in ICP and change in JBP. Intracranial pressue after RTP resulted in decreased tension of the dura. RTP appears to be an effective means of reducing ICP during craniotomy, thereby reducing the risk of cerebral herniation. CPP is not affected. Studies over longer periods of time are warranted, however.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

We tested the hypothesis that transtentorial herniation (TTH) represents a state of cerebral ischemia that can be reversed by hypertonic saline. Because of the high mortality associated with TTH, new therapeutic strategies need to be developed for rapid and effective reversal of this process. We produced TTH (defined by acute dilatation of one or both pupils) by creating supratentorial intracerebral hemorrhage with autologous blood injection in seven mongrel dogs anesthetized using intravenous pentobarbital and fentanyl. We measured serial rCBF (regional cerebral blood flow) using radiolabeled microspheres in regions around and distant to the hematoma. Cerebral oxygen extraction and oxygen consumption (CMRO2) were measured by serial sampling of cerebral venous blood from the sagittal sinus. Mean arterial pressure (MAP) and intracranial pressure (ICP) were continuously monitored. TTH was successfully reversed over a mean period of 25.7 ± 4.9 minutes after intravenous administration of 23.4% sodium chloride (1.4 mL/kg) in all animals. All measurements were recorded 15, 30, 60, and 90 minutes after administration of 23.4% sodium chloride. Compared to prehematoma ICP (14.1 ± 1.7 mm Hg, mean ± SE), elevation in ICP was observed during TTH (36.2 ± 7.2 mm Hg) with no change in cerebral perfusion pressure (CPP) (80.4 ± 4.7 vs. 76.7 ± 10.1 mm Hg) because of concomitant elevation in mean arterial pressure. Compared to baseline values, there was a reduction in rCBF (mL/100 gm/min ± SE) in brainstem (12.1 ± 2.0 vs. 21.4 ± 1.4), gray matter (18.2 ± 2.1 vs. 31.4 ± 1.8), and white matter (8.6 ± 1.7 vs.18.7 ± 0.9) in the hemisphere contralateral to the hematoma; and gray matter (12.9 ± 2.9 vs. 27.9 ± 2.2) and white matter (8.3 ± 2.0 vs.19.9 ± 1.0) in the ipsilateral hemisphere distant from the hematoma. Administration of 23.4% sodium chloride resulted in reduced ICP at 15 minutes (12.7 ± 1.4) and 30 minutes (15.6 ± 3.1) after administration. RCBF values were restored in all regions studied after administration of 23.4% sodium chloride with an increase in CMRO2(1.8 ± 0.4 vs. 3.9 ± 0.7 mL O2/100 gm/min). Compared with baseline values, rCBF increased in the ipsilateral (31.7 ± 2.5 vs. 63.4 ± 11.7) and contralateral (28.7 ± 1.9 vs. 45.5 ± 5.7) thalamus at 15 minutes after administration of 23.4% sodium chloride. TTH represented a state of ischemia in brainstem and supratentorial gray and white matter in the presence of adequate CPP, suggesting mechanical compression of vessels at the level of tentorium. Hypertonic saline reversed TTH, and restored both rCBF and CMRO2, although hyperemia was observed immediately after reversal of TTH. Administration of hypertonic saline may preserve neurologic function during the interim period between TTH and surgical intervention.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Using a rabbit model of intracranial hypertension, we studied the effects of infusion of phenylephrine on intracranial pressure (ICP) and cerebral perfusion pressure (CPP). Seven New Zealand white rabbits were anesthetized with isoflurane and normocapnia was maintained. An extradural balloon was used to raise ICP to 25 ± 1 mm Hg. Infusion of phenylephrine increased mean arterial blood pressure (MAP) (77 ± 6 → 95 ± 8 mm Hg) and CPP (52 ± 7 → 70 ± 7 mm Hg). ICP was unchanged during infusion of phenylephrine (25 ± 1 vs. 25 ± 2 mm Hg). The phenylephrine infusion was stopped after 45 minutes and MAP returned to baseline (76 ± 8 mm Hg). We conclude that phenylephrine increased CPP because of its effect on MAP, but did not alter ICP. Phenylephrine may be used to increase CPP without raising ICP when autoregulation is intact.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Inhibition of neurotoxic events that lead to delayed cellular damage may prevent motor function loss after transient spinal cord ischemia. An important effect of the neuroprotective substance aminoguanidine (AG) is the inhibition of inducible nitric oxide synthase (iNOS), a perpetrator of focal ischemic damage. The authors studied the protective effects of AG on hind limb motor function and histopathologic outcome in an experimental model for spinal cord ischemia, and related these findings to the protein content of iNOS in the spinal cord. Temporary spinal cord ischemia was induced by 28 minutes of infrarenal balloon occlusion of the aorta in 40 anesthetized New Zealand White rabbits. Animals were assigned randomly to two treatments: saline (n = 20) or AG (n = 20; 100 mg/kg intravenously before occlusion). Postoperatively, treatment was continued with subcutaneous injections twice daily (saline or 100 mg/kg AG). Normothermia (38°C) was maintained during ischemia, and rectal temperature was assessed before and after subcutaneous injections. Animals were observed for 96 hours for neurologic evaluation (Tarlov score), and the lumbosacral spinal cord was examined for ischemic damage after perfusion and fixation. Lastly, iNOS protein content was determined using Western blot analysis 48 hours after ischemia in five animals from each group. Neurologic outcome at 96 hours after reperfusion was the same in both groups. The incidence of paraplegia was 67% in the saline-treated group versus 53% in the AG-treated group. No differences in infarction volume, total number of viable motoneurons, or total number of eosinophilic neurons were present between the groups. At 48 hours after reperfusion, iNOS protein content in the spinal cord was increased in one animal in the AG-treated group and in three animals in the control group. The data indicate that peri-ischemic treatment with high-dose AG in rabbits offers no protection against a period of normothermic spinal cord ischemia. There was no conclusive evidence of spinal cord iNOS inhibition after treatment with AG.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

A 79-year-old woman with no history of myocardial ischemia presented with symptoms of pituitary apoplexy for which an urgent transsphenoidal resection of the pituitary gland was undertaken. The nasal passages were prepared with topical application of epinephrine followed by injection of what was presumed to be 1% lidocaine containing 10 &mgr;g/ml−1of epinephrine. After only 1.5 mL of the solution had been injected, she developed a hypertensive crisis, which was immediately treated. Postoperatively, she developed a myocardial infarction. The risks associated with the use of vasopressors are reviewed and suggestions for their safe use are presented.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Coronary vasospasm resulting from a sudden autonomic response associated with an intracranial procedure was encountered during percutaneous radiofrequency trigeminal rhizotomy. Although it is very rare, careful monitoring and readiness for the occurrence of such a potentially lethal situation with necessary medications may prevent a fatal outcome.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

In patients with head injury, endotracheal suctioning (ETS) is a potentially dangerous procedure, because it can increase intracranial pressure (ICP). The purpose of this prospective nonrandomized study was to evaluate the impact of ETS on intracranial dynamics in the acute phase of head injury. Seventeen patients with severe head injury (Glasgow Coma Score ≤ 8, range 4–8), sedated and mechanically ventilated, were studied during the first week after trauma. Single-pass ETS maneuver (with a 16-French catheter, negative pressure of 100 mm Hg, and duration of less than 30 seconds) was performed 60 seconds after the FiO2was increased to 100%. After ETS, FiO2was maintained at 100% for another 30 seconds. Before and after ETS, arterial blood gases and jugular oxygen saturation (SjO2), ICP, and mean arterial pressure (MAP) were measured and cerebral perfusion pressure (CPP) was calculated. A total of 131 ETS episodes, which consisted of repeated assessment of each patient, were analyzed. Six patients in 20 cases coughed and/or moved during ETS because of inadequate sedation. After ETS, ICP increased from 20 ± 12 to 22 ± 13 mm Hg in well-sedated patients and from 15 ± 9 to 28 ± 9 mm Hg in patients who coughed and/or moved (mean change, 2 ± 6 versus 13 ± 6 mm Hg,P<.0001). CPP and SjO2increased in well-sedated patients (from 78 ± 16 to 83 ± 19 mm Hg, and from 71 ± 10 to 73 ± 13%, respectively) and decreased in patients who reacted to ETS (from 79 ± 14 to 72 ± 14 mm Hg and from 69 ± 7 to 66 ± 9%, respectively), and the differences were significant (mean change, CPP: 5 ± 14 versus -7 ± 15 mm Hg,P=.003; (SjO2) 2 ± 5 vs. −3 ± 5%,P<.0001). In well-sedated patients, endotracheal suctioning caused an increase in ICP, CPP, and SjO2without evidence of ischemia. In contrast, in patients who coughed or moved in response to suctioning, there was a slight and significant decrease in CPP and SjO2. In the case of patients with head injuries who coughed or moved during endotracheal suctioning, we strongly suggest deepening the level of sedation before completing the procedure to reduce the risk of adverse effects.

ISSN:0898-4921    

出版商:OVID    

年代:2002

数据来源: OVID