Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2000
Randomized Controlled Trial Clinical TrialThe effect of patient positioning on intraabdominal pressure and blood loss in spinal surgery.
Intraabdominal pressure (IAP) can influence blood loss during spinal surgery. We examined the relationship of IAP changes to blood loss with a rectal balloon pressure catheter. Forty patients were randomly assigned to narrow (Group 1) or wide (Group 2) pad support widths of the Wilson frame. IAP was measured when the patient was supine after the induction of anesthesia, prone on a gurney, prone on the Wilson frame before and after incision, and then, again supine after tracheal extubation. IAP in the prone position on the Wilson frame before incision (3.6 cm H(2)O) in Group 2 was significantly less than in Group 1 (8.8 cm H(2)O) (P: < 0.05). Intraoperative blood loss per vertebra in Group 2 (190 +/- 65 mL) was significantly less than in Group 1 (381 +/- 236 mL) (P: < 0.05). The correlation between blood loss and IAP in the prone position on the Wilson frame in Group 1 was significant (P: = 0.0022). In conclusion, IAP and intraoperative blood loss were significantly less in the wide, than in the narrow, pad support width of the Wilson frame. Blood loss tended to increase with an increase in IAP in the narrow pad support width of the Wilson frame. ⋯ The relationship of intraabdominal pressure changes to blood loss were examined with a rectal balloon pressure catheter during spinal surgery. Blood loss tended to increase with an increase in intraabdominal pressure in the narrow pad support width of the Wilson frame.
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Anesthesia and analgesia · Sep 2000
Randomized Controlled Trial Clinical TrialEvaluating hemodynamic and T wave criteria of simulated intravascular test doses using bupivacaine or isoproterenol in anesthetized children.
An increase in T wave amplitude > or =25% is a reliable indicator for detecting intravascular injection of lidocaine-epinephrine test dose in anesthetized children. We examined whether a simulated IV test dose containing bupivacaine instead of lidocaine, and isoproterenol instead of epinephrine, produces reliable changes in heart rate (HR) and T wave morphology. One hundred healthy infants and children (6-72 mo) were randomized to one of five groups (n = 20 each) during 1.0 minimum alveolar anesthetic concentration sevoflurane and 67% nitrous oxide in oxygen: atropine pretreatment (0.01 mg/kg IV) followed by 0.25% bupivacaine containing epinephrine 0.5 microg/kg IV, atropine followed by normal saline, atropine followed by 1% lidocaine containing isoproterenol 0.1 microg/kg, saline pretreatment followed by the lidocaine-isoproterenol test dose, and saline followed by saline. HR was recorded every 20 s and T wave amplitude of lead II was continuously recorded. All patients receiving the bupivacaine-epinephrine test dose and none receiving saline met the HR (positive if > or =10 bpm increase) and T wave criteria (positive if > or =25% increase in amplitude). The isoproterenol-containing test dose produced positive responses based only on the HR criterion with or without atropine pretreatment. Our results indicate that HR and T wave changes are useful if a bupivacaine-epinephrine test dose is used and that HR is the only useful indicator if an isoproterenol-containing test dose is used in sevoflurane-anesthetized children. ⋯ To determine if an epidurally administered local anesthetic has been unintentionally injected into a blood vessel, a small dose of epinephrine or isoproterenol may be added to a local anesthetic. We found that an increase in heart rate > or =10 bpm and an increase in T wave amplitude of lead II >or =25% are useful indicators for detecting accidental intravascular injection of an epinephrine-containing test dose in sevoflurane-anesthetized children, whereas only a heart rate change is a reliable diagnostic tool if an isoproterenol-containing test dose is used.
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Anesthesia and analgesia · Sep 2000
Randomized Controlled Trial Clinical TrialThermosoftening treatment of the nasotracheal tube before intubation can reduce epistaxis and nasal damage.
We evaluated whether a thermosoftening treatment with warm saline of a nasotracheal preformed tube can improve navigability through the nasal passageways and reduce epistaxis and nasal damage. A total of 150 patients were randomly allocated to three groups: Group I (untreated tube group, n = 50), Group II (35 degrees C treated tube group, n = 50), and Group III (45 degrees C treated tube group, n = 50). In Groups II and III, the tubes were softened at 35 +/- 2 degrees C and 45 +/- 2 degrees C with warm saline, respectively. In Group I the tube was prepared at room temperature (25 +/- 2 degrees C). The incidence of epistaxis and nasal damage in Groups II and III was significantly less than that of Group I (P: < 0.05). Despite the more frequent incidence of smooth passage in Group III, no statistical difference was found among the groups. Logistic regression analysis also confirmed that epistaxis was more likely to be reduced when the tube had been thermosoftened (odds ratio = 1.46, 95% confidence interval = 1.02, 2.11). We conclude that simple thermosoftening treatment of the nasotracheal tube with warm saline helps to reduce epistaxis and nasal damage. ⋯ Thermosoftening treatment of a nasotracheal tube with warm saline before intubation can effectively reduce epistaxis and nasal damage. This technique is safe, easy, and suitable for all types of tubes and does not require additional implements.
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Anesthesia and analgesia · Sep 2000
Comparative Study Clinical Trial Controlled Clinical TrialContinuous positive airway pressure at 10 cm H(2)O during cardiopulmonary bypass improves postoperative gas exchange.
Postbypass pulmonary dysfunction including atelectasis and increased shunting is a common problem in the intensive care unit. Negative net fluid balance and continuous positive airway pressure (CPAP) have been used to reduce the adverse effects of cardiopulmonary bypass (CPB) on the lung. To determine whether CPAP at 10 cm H(2)O during CPB results in improved postoperative gas exchange in comparison with deflated lungs during CPB, we examined 14 patients scheduled for elective cardiac surgery. Seven patients received CPAP at 10 cm H(2)O during CPB, and in the other seven patients, the lungs were open to the atmosphere (control). Measurements were taken before and after CPB, after thoracic closure, and 4 h after CPB in the intensive care unit. CPAP at 10 cm H(2)O resulted in significantly more perfusion of lung areas with a normal ventilation/perfusion distribution (V(A)/Q) and significantly less shunt and low V(A)/Q perfusion 4 h after CPB in comparison with the control group. Consequently, arterial oxygen partial pressure was significantly higher and alveolar-arterial oxygen partial pressure difference was significantly smaller. We conclude that CPAP at 10 cm H(2)O during CPB is a simple maneuver that improves postoperative gas exchange. ⋯ Inflation of the lungs at a pressure of 10 cm H(2)O as compared with leaving the lungs deflated during cardiopulmonary bypass was examined. Lung inflation during bypass resulted in significantly improved postoperative gas exchange.
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Anesthesia and analgesia · Sep 2000
Clinical TrialTemperature monitoring and management during neuraxial anesthesia: an observational study.
Temperature monitoring and thermal management are rare during spinal or epidural anesthesia because clinicians apparently restrict monitoring to patients with an expected risk of hypothermia. This implies that anesthesiologists can predict patient thermal status without monitoring core temperature. We therefore, tested the hypotheses that during neuraxial anesthesia: 1) amount of core hypothermia depends on the magnitude and duration of surgery; 2) temperature monitoring and thermal management are used selectively in patients at high risk of hypothermia; and 3) anesthesiologists can estimate patient thermal status. We evaluated thermal status on arrival in the recovery room along with intraoperative thermal management and monitoring in 120 patients. Anesthesiologists were asked if their patients were hypothermic (<36 degrees C). There was no correlation between the magnitude or duration of surgery and initial postoperative core temperature in unwarmed patients. Temperature monitoring and thermal management were not used selectively in high-risk patients. Initial postoperative tympanic membrane temperatures were <36 degrees C in 77% of patients and <35 degrees C in 22%. Body temperature was monitored intraoperatively in 27% of the patients and forced-air warming was used in 31%. Anesthesiologists failed to accurately estimate whether their patients were hypothermic. Our results suggest that temperature monitoring and management during neuraxial anesthesia is currently inadequate. ⋯ In this observational study, we evaluated core temperatures and intraoperative thermal management in patients undergoing spinal or epidural anesthesia. Hypothermia was common, however, rarely detected either by temperature monitoring or estimates by anesthesiologists. In addition, it was not treated with active warming. Consequently, temperature monitoring and management have to be done during neuraxial anesthesia.