Anesthesia and analgesia
-
Anesthesia and analgesia · Dec 2002
The effect of alterations in a preoperative assessment clinic on reducing the number and improving the yield of cardiology consultations.
Although preoperative assessment testing clinics (PATCs) can produce efficiency in the evaluation of surgical candidates, their effect on the use of consultants has not been studied. We hypothesized that changes in PATC procedures, education, and staffing could affect the use and yield of cardiology consultations. All PATC anesthesiologist-requested cardiology consultations for patients undergoing elective noncardiac surgery from 1993 to 1999 were reviewed. This period corresponded to 3 yr before and after a change in the PATC leadership, which resulted in more stringent consultation algorithms, a cardiac assessment and electrocardiogram interpretation educational program, and altered staffing of anesthesiologists and ancillary personnel. A single senior cardiologist completed all consultations. Data including age, sex, reason for consultation, resultant testing, consultant conclusions, cancellations, and surgical procedure and outcomes were collected. In the PRE and POST groups, respectively, 917 and 279 consultations (1.46% versus 0.49% [P = 0.0001] of noncardiovascular surgeries) were ordered despite an increase in the surgical case-mix acuity. In the POST group, significantly fewer consultations were ordered and significantly more required further testing to assess cardiac status. We conclude that changes in PATC consultation algorithms, education, and staffing can significantly decrease the use and yield of preoperative cardiology consultations. ⋯ Alterations in preoperative assessment testing clinic consultation algorithms, education, and staffing can significantly reduce the use of preoperative cardiology consultations while improving their overall yield.
-
Anesthesia and analgesia · Dec 2002
Interactions of volatile anesthetics with cholinergic, tachykinin, and leukotriene mechanisms in isolated Guinea pig bronchial smooth muscle.
We studied relaxation of airway smooth muscle by sevoflurane, desflurane, and halothane in isolated guinea pig bronchi. Ring preparations were mounted in tissue baths filled with physiological salt solution and continuously aerated with 5% CO(2) in oxygen. Electrical field stimulation induced contractions sensitive to tetrodotoxin, indicating nerve-mediated responses. These consisted of an atropine-sensitive cholinergic phase and a nonadrenergic noncholinergic (NANC) phase sensitive to SR48968, a neurokinin-2 receptor antagonist. Anesthetics were added to the gas aerating the tissue baths. Sevoflurane and desflurane at 1.0 minimum alveolar anesthetic concentration and halothane at 1.0-2.0 minimum alveolar anesthetic concentrations inhibited both cholinergic and NANC contractions to electrical field stimulation. None of the anesthetics affected responses to exogenously applied neurokinin A, a likely mediator of NANC contractions, suggesting prejunctional inhibition of NANC neurotransmission. The anesthetics did not affect the initiation of contractile responses to leukotriene C(4) (LTC(4)), a mediator of asthmatic bronchoconstriction. However, sevoflurane and desflurane both relaxed bronchi in a steady-state contraction achieved by LTC(4). Surprisingly, halothane did not relax LTC(4) contractions. Concerning LTC(4)-elicited bronchoconstriction, sevoflurane and desflurane were more potent airway smooth muscle relaxants in vitro. ⋯ Halothane, sevoflurane, and desflurane attenuated airway smooth muscle tone via inhibition of cholinergic and nonadrenergic noncholinergic neurotransmission. Sevoflurane and desflurane reduced leukotriene C(4)-induced bronchoconstriction, whereas halothane did not. This indicates a beneficial role for sevoflurane and desflurane in asthmatics.
-
Anesthesia and analgesia · Dec 2002
The impact of a cardioprotective protocol on the incidence of cardiac complications after aortic abdominal surgery.
We analyzed a local database including 468 consecutive patients who underwent elective aortic abdominal surgery over an 8-yr period in a single institution. A new cardioprotective perioperative protocol was introduced in January 1997, and we questioned whether perioperative cardiac outcome could be favorably influenced by the application of a stepwise cardiovascular evaluation based on the American College of Cardiology/American Heart Association guidelines and by the use of antiadrenergic drugs. Clonidine was administered during surgery, and beta-blockers were titrated after surgery to achieve heart rates less than 80 bpm. We compared data of two consecutive 4-yr periods (1993-1996 [control period] versus 1997-2000 [intervention period]). Implementation of American College of Cardiology/American Heart Association guidelines was associated with increased preoperative myocardial scanning (44.3% vs 20.6%; P < 0.05) and coronary revascularization (7.7% vs 0.8%; P < 0.05). During the intervention period, there was a significant decrease in the incidence of cardiac complications (from 11.3% to 4.5%) and an increase in event-free survival at 1 yr after surgery (from 91.3% to 98.2%). Multivariate regression analysis showed that the combined administration of clonidine and beta-blockers was associated with a decreased risk of cardiovascular events (odds ratio, 0.3; 95% confidence interval, 0.1-0.8), whereas major bleeding, renal insufficiency, and chronic obstructive pulmonary disease were predictive of cardiac complications. In conclusion, cardiac testing was helpful to identify a small subset of high-risk patients who might benefit from coronary revascularization. Sequential and selective antiadrenergic treatments were associated with improved postoperative cardiac outcome. ⋯ Implementation of American College of Cardiology/American Heart Association guidelines and use of antiadrenergic drugs were associated with better cardiac outcomes after major vascular surgery.
-
Anesthesia and analgesia · Dec 2002
Case ReportsContinuous sacral nerve root block in the management of neuropathic cancer pain.
Neuropathic cancer pain caused by tumor infiltration in the sacral plexus is primarily treated by nonsteroidal antiinflammatory drugs, antidepressants, anticonvulsants, and opioids. In one patient with severe pain despite pharmacotherapy, a catheter for the continuous administration of local anesthetics was inserted along the first sacral root, resulting in markedly improved analgesia.
-
Anesthesia and analgesia · Dec 2002
Evaluating the relationship between arterial blood pressure changes and indices of pulse oximetric plethysmography.
The finger plethysmographic waveform of pulse oximeters is a qualitative indicator of fingertip perfusion. This waveform has been used to assess the depth of anesthesia. Its cyclical changes associated with mechanical ventilation have also been used to detect changes in blood volume under normotensive conditions and has revealed that minimal normotensive hypovolemia can cause a significant increase in the delta-down component of this waveform. Hypovolemia may be associated with hypotension; the latter may be due to causes other than hypovolemia. Because the effects of the hypotension on plethysmographic waveform have not been evaluated, it may be difficult to detect hypovolemia in these conditions by inspecting a plethysmogram. Therefore, we performed this study to evaluate the effect of normovolemic hypotension on characteristics of plethysmographic waveform in 33 adult patients undergoing general anesthesia with controlled hypotension. The delta-down and ventilatory systolic variation components were increased significantly with decreases in systolic blood pressure. The result of this study shows that the effect of pharmacologic hypotension on the plethysmographic waveform of pulse oximeter is similar to that of minimal hypovolemia. Therefore, blood volume may be inaccurately assessed by the inspection of ventilatory-induced cyclical changes of pulse oximetric waveform in the presence of hypotension. ⋯ The cyclical respiratory-induced changes in the amplitude of the pulse oximeter waveform can be used to detect normotensive hypovolemia. This study shows that hypotension produces the same effect. Therefore, in hypotensive conditions, we cannot determine the presence of hypovolemia.