Pamela M. Maxson

Lower extremity neuropathies associated with lithotomy positions

BackgroundThe goal of this project was to study the frequency and natural history of perioperative lower extremity neuropathies. MethodsA prospective evaluation of lower extremity neuropathies in 991 adult patients undergoing general anesthetics and surgical procedures while positioned in lithotomy was performed. Patients were assessed with use of a standard questionnaire and neurologic examination before surgery, daily during hospital stay in the first week after surgery, and by phone if discharged before 1 postoperative week. Patients in whom lower extremity neuropathies developed were observed for 6 months. ResultsLower extremity neuropathies developed in 15 patients (1.5%; 95% confidence interval, 0.8–2.5%). Unilateral or bilateral nerves were affected in patients as follows: obturator (five patients), lateral femoral cutaneous (four patients), sciatic (three patients), and peroneal (three patients). Paresthesia occurred in 14 of 15 patients, and 4 patients had burning or aching pain. No patient had weakness. Symptoms were noted within 4 h of completion of the anesthetic in all 15 patients. These symptoms resolved within 6 months in 14 of 15 patients. Prolonged positioning in a lithotomy position, especially for more than 2 h, was a major risk factor for this complication (P = 0.006). ConclusionsIn this surgical population, lower extremity neuropathies were infrequent complications that were noted very soon after surgery and anesthesia. None resulted in prolonged disability. The longer patients were positioned in lithotomy positions, the greater the chance of development of a neuropathy. These findings suggest that a reduction of duration of time in lithotomy positions may reduce the risk of lower extremity neuropathies.

Perianesthetic risks and outcomes of pheochromocytoma and paraganglioma resection

Pheochromocytomas and paragangliomas are often surgically curable. However, resection of these tumors can be life threatening. We undertook this study to determine the frequency of, and risk factors for, perioperative complications in patients undergoing resection of pheochromocytoma or paraganglioma. We retrospectively reviewed the medical records of patients during 1983–1996 who underwent surgical resection of catecholamine-secreting pheochromocytoma or paraganglioma. Preoperative risk factors, adverse intraoperative events, and complications occurring in the 30 days after operation were recorded. Blood pressures were collected from manual records. The ranked sum test and Fisher’s exact test were used for analyses. Adverse perioperative events or complications occurred in 45 of 143 patients (31.5%; exact 95% confidence interval, 24.0% to 39.8%). Of these 45 patients, 41 experienced one or more adverse intraoperative events. The most common adverse event was sustained hypertension (36 patients). There were no perioperative deaths, myocardial infarctions, or cerebrovascular events. Preoperative factors univariately associated with adverse perioperative events included larger tumor size (P = 0.007), prolonged duration of anesthesia (P = 0.015), and increased levels of preoperative urinary catecholamines and catecholamine metabolites: vanillylmandelic acid (P = 0.019), metanephrines (P = 0.004), norepinephrine (P = 0.014), and epinephrine (P = 0.004). Despite premedication of most patients with phenoxybenzamine and a &bgr;-adrenergic blocker, varying degrees of intraoperative hemodynamic lability occurred. Implications Few patients who had pheochromocytoma or paraganglioma resection experienced significant perioperative morbidity and none died in the largest retrospective study on this topic to date. This study confirms the very good perioperative outcomes demonstrated in smaller studies on this high-risk population, and identifies several risk factors for adverse outcomes.

perianesthetic Dental Injuries : Frequency, Outcomes, and Risk Factors

BACKGROUND Dental injury is well-recognized as a potential complication of laryngoscopy and tracheal intubation. However, the frequency, outcomes, and risk factors for this problem have not been documented in a well-defined patient population. METHODS The authors analyzed the dental injuries of 598,904 consecutive cases performed on patients who required anesthetic services from 1987 through 1997. Dental injuries were defined as perianesthetic events (those occurring within 7 days) that required dental interventions to repair, stabilize, or extract involved dentition or support structures. A 1:3 case-control study of 16 patient and procedural characteristics was performed for cases that occurred during the first 5 yr of the study. Conditional logistic regression was used for data analysis. RESULTS There were 132 cases (1:4,537 patients) of dental injury. One half of these injuries occurred during laryngoscopy and tracheal intubation. The upper incisors were the most commonly involved teeth, and most injuries were crown fractures and partial dislocations and dislodgements. Multivariate risk factors for dental injury in the case control study included general anesthesia with tracheal intubation (odds ratio [OR] = 89), preexisting poor dentition (OR = 50), and increased difficulty of laryngoscopy and intubation (OR = 11). CONCLUSIONS Based on these data from a large surgical population at a single training institution, approximately 1:4,500 patients who receive anesthesia services sustain a dental injury that requires repair or extraction. Patients most at risk for perianesthetic dental injury include those with preexisting poor dentition who have one or more risk factors for difficult laryngoscopy and tracheal intubation.

Airway obstruction and perioperative complications in smokers undergoing abdominal surgery

BACKGROUND The goal of this study was to determine whether airway obstruction determined by preoperative spirometry predicts perioperative complications in smokers undergoing abdominal surgery whose treatment is managed according to current clinical practice. METHODS A pulmonary function database identified patients undergoing abdominal surgery who met the following criteria for airway obstruction (n = 135): a forced expiratory volume less than 40% of predicted normal value, a forced expiratory volume:forced vital capacity ratio less than the lower limit of predicted normal, a smoking history of more than 20 pack-years, and an age older than 35 yr. A group of patients without airway obstruction (n = 135) was matched for gender, surgical site (upper vs. lower abdominal), smoking history, and age. Medical records were reviewed by an abstractor to identify perioperative complications that occurred within 30 days after surgery. RESULTS The forced expiratory volume values were 0.9+/-0.21 (mean +/- SD) and 2.9+/-0.61 in patients with and without airway obstruction, respectively. When analyzed by conditional logistic regression using the 1:1 matched-pairs feature, including age, pack-year smoking history, site of incision, and current smoking status as covariates, in patients with airway obstruction bronchospasm was more likely to develop (odds ratio, 6.9 [95% confidence interval, 1.2 to 38.4]) but the patients were not more likely to need prolonged endotracheal intubation (odds ratio, 1.1 [95% confidence interval, 0.4 to 3.2]). They were also no more likely to need prolonged intensive care admission or readmission. The frequency of other complications was less than 5%. CONCLUSION When other factors were considered, preoperative airway obstruction predicted the occurrence of bronchospasm, but not prolonged endotracheal intubation, in smokers undergoing abdominal surgery who are treated according to current clinical practices.

The risk of persistent paresthesia is not increased with repeated axillary block.

UNLABELLED Neurologic deficits are noted on physical examination in approximately 0.2%-19% of patients after regional anesthetic techniques. Laboratory and clinical studies suggest that a subclinical neuropathy occurs much more often. Performing a regional anesthetic technique during this period may result in additional nerve trauma. We evaluated the frequency of neurologic complications in patients undergoing repeated axillary block. A total of 1614 blocks were performed on 607 patients. The median number of blocks per patient was two (range 2-10 blocks). The median interval between blocks was 12.6 wk, including 188 (31%) patients who received multiple blocks within 1 wk. Sixty-two neurologic complications occurred in 51 patients for an overall frequency of 8.4%. Of the 62 nerve injuries, 7 (11.3%) were related to the anesthetic technique; the remaining 55 (88.7%) were a result of the surgical procedure. Patient age and gender, the presence of preexisting neurologic conditions, a surgical procedure to a nerve, and total number of blocks did not increase the risk of neurologic complications. No regional anesthetic technique risk factors, including elicitation of a paresthesia, selection of local anesthetic, or addition of epinephrine, were identified. The success rate was higher with the paresthesia technique than with nerve stimulator technique or transarterial injection, and with use of mepivacaine versus bupivacaine. We conclude that the frequency of neurologic complications in patients undergoing repeated axillary block is similar to that in patients receiving a single regional technique. These patients are not likely to be at increased risk of neurologic complications. IMPLICATIONS The risk of neurologic complications was not increased in patients who underwent multiple axillary blocks, even within a 1-wk interval. No risk factors for anesthetic-related complications were identified. However, block success rate was increased with the paresthesia technique and the injection of mepivacaine versus bupivacaine.

Ulnar neuropathy in surgical patients

BackgroundThe goal of this project was to study the frequency and natural history of perioperative ulnar neuropathy.MethodsA prospective evaluation of ulnar neuropathy in 1,502 adult patients undergoing noncardiac surgical procedures was performed. Patients were assessed with a standard questionnair

Risk of surgery and anesthesia for ischemic stroke.

Background The goal of this study was to determine if the combination of surgery and anesthesia is an independent risk factor for the development of incident (first-time) ischemic stroke. Methods All residents of Rochester, MN, with incident ischemic stroke from 1960 through 1984 (1,455 cases and 1,455 age- and gender-matched controls) were used to identify risk factors associated with ischemic stroke. Cases and controls undergoing surgery involving general anesthesia or central neuroaxis blockade before their stroke/index date of diagnosis were identified. A conditional logistic regression model was used to estimate the odds ratio of surgery and anesthesia for ischemic stroke while adjusting for other known risk factors. Results There were 59 cases and 17 controls having surgery within 30 days before their stroke/index date. After adjusting for previously identified risk factors, surgery within 30 days before the stroke/index date (perioperative period) was found to be an independent risk factor for stroke (P < 0.001; odds ratio, 3.9; 95% confidence interval, 2.1–7.4). In an analysis that excluded matched pairs where the case and/or control underwent surgery considered “high risk” for stroke (cardiac, neurologic, or vascular procedures), “non–high-risk surgery” was also found to be an independent risk factor for perioperative stroke (P = 0.002; odds ratio, 2.9; 95% confidence interval, 1.5–5.7). Conclusion Our results suggest that there is an increased risk of ischemic stroke in the 30 days after surgery and anesthesia. This risk remains elevated even after excluding surgeries (cardiac, neurologic, and vascular surgeries) considered to be high risk for ischemic stroke.

Enhancing Nurse and Physician Collaboration in Clinical Decision Making Through High-fidelity Interdisciplinary Simulation Training

OBJECTIVE To determine whether interdisciplinary simulation team training can positively affect registered nurse and/or physician perceptions of collaboration in clinical decision making. PARTICIPANTS AND METHODS Between March 1 and April 21, 2009, a convenience sample of volunteer nurses and physicians was recruited to undergo simulation training consisting of a team response to 3 clinical scenarios. Participants completed the Collaboration and Satisfaction About Care Decisions (CSACD) survey before training and at 2 weeks and 2 months after training. Differences in CSACD summary scores between the time points were assessed with paired t tests. RESULTS Twenty-eight health care professionals (19 nurses, 9 physicians) underwent simulation training. Nurses were of similar age to physicians (27.3 vs 34.5 years; p = .82), were more likely to be women (95.0% vs 12.5%; p < .001), and were less likely to have undergone prior simulation training (0% vs 37.5%; p = .02). The pretest showed that physicians were more likely to perceive that open communication exists between nurses and physicians (p = .04) and that both medical and nursing concerns influence the decision-making process (p = .02). Pretest CSACD analysis revealed that most participants were dissatisfied with the decision-making process. The CSACD summary score showed significant improvement from baseline to 2 weeks (4.2 to 5.1; p < .002), a trend that persisted at 2 months (p < .002). CONCLUSION Team training using high-fidelity simulation scenarios promoted collaboration between nurses and physicians and enhanced the patient care decision-making process.

Neurologic complications after placement of cerebrospinal fluid drainage catheters and needles in anesthetized patients: Implications for regional anesthesia

UNLABELLED Subarachnoid or epidural needle placement in an anesthetized patient is controversial because general anesthesia and muscle relaxation may mask neural trauma. However, placement of a needle or catheter in the subarachnoid space for the purpose of cerebral spinal fluid (CSF) drainage is frequently performed in anesthetized patients undergoing neurosurgery. The records from 530 consecutive transsphenoidal surgeries performed with lumbar CSF drainage were reviewed to determine the types of neurologic complications attributable to spinal drainage and their rates of occurrence. All patients were anesthetized during CSF drain placement. A 19-gauge malleable needle was placed in 473 (89%) patients. Subarachnoid catheters (20- or 16-gauge catheters placed via 18- or 14-gauge epidural needles, respectively) were placed in 17 (3%) patients. In 40 (8%) patients, the type of drain was unspecified. No new neurologic deficits attributable to spinal drain insertion were detected in the immediate postoperative period or within 1 yr of surgery. Thirteen patients developed postdural puncture headache (2.5%, exact 95% confidence interval 1.3%-4.2%); seven required epidural blood patch (1.3%, 0.5%-2.7%). The low incidence (0%, 0.0%-0.7%) of neurologic injury from spinal drain insertion in anesthetized patients from this study is similar to the incidence of neurologic complications historically reported for both CSF drain insertion and spinal anesthesia. IMPLICATIONS The performance of regional anesthesia in an anesthetized patient is controversial due to the possibility of unrecognized nerve injury. We report no cases of nerve injury caused by the placement of cerebrospinal fluid drainage needles and catheters in 530 anesthetized patients undergoing neurosurgery.

Ulnar Neuropathy in Medical Patients

ANESTHETIZED patients who undergo surgical procedures may develop ulnar neuropathy. 1-6 Although the mechanism of ulnar neuropathy in the perioperative setting is often unclear, improper positioning or padding of the upper extremity during surgery is sometimes implicated 7,8 ; however, there is little direct evidence to implicate improper intraoperative care as a cause of perioperative ulnar neuropathy. Several studies have noted that surgical patients may develop symptoms of this complication in the presence of appropriate care. 4,6 6 Recently, we reported that 7 of 1,502 prospectively studied surgical patients (0.5%) developed perioperative ulnar neuropathy. 9 All seven patients reported an initial onset of symptoms 2-7 days after their procedure, which suggests that one or more factors in the postoperative period may contribute to ulnar neuropathy. Postoperative patients and patients who are admitted with medical conditions may have similar hospital-care characteristics (e.g., bedrest). Do medical patients who are not undergoing surgery also develop ulnar neuropathy during hospitalization This report describes a prospective study of ulnar neuropathy in patients admitted to internal medicine services for nonsurgical conditions, and reports on two of these patients who developed ulnar neuropathy during the first week after admission.