Christopher M. Burkle

Anesthetic, patient, and surgical risk factors for neurologic complications after prolonged total tourniquet time during total knee arthroplasty

Nerve injury after prolonged tourniquet inflation results from the combined effects of ischemia and mechanical trauma. Tourniquet release, allowing a reperfusion interval of 10–30 min followed by re-inflation, has been recommended to extend the duration of total tourniquet time. However, this practice has not been confirmed clinically. We retrospectively reviewed the medical records of 1001 patients undergoing 1166 primary or revision knee replacements with tourniquet time more than 120 min during a 5-yr interval. Mean total tourniquet time was 145 ± 25 min (range, 120–308 min). In 759 patients, the tourniquet inflation was uninterrupted. Two tourniquet inflations, interrupted by a single deflation, were noted in 371 patients, and 3 tourniquet inflations interrupted by 2 deflation intervals were noted in 23 patients. A total of 129 neurologic complications (peroneal and/or tibial nerve palsies) were noted in 90 patients for an overall incidence of 7.7%. Eighty-five cases involved the peroneal nerve and 44 cases involved the tibial nerve. In 39 cases, both peroneal and tibial deficits were noted. Complete neurologic recovery occurred in 76 (89%) peroneal and 44 (100%) tibial palsies. Postoperative neurologic dysfunction was associated with younger age (P < 0.001; odds ratio = 0.7 per 10-yr increase), longer tourniquet time (P < 0.001; odds ratio = 2.8 per 30-min increase), and preoperative flexion contracture >20° (P = 0.002; odds ratio = 3.9). In a subset of 116 patients with tourniquet times ≥180 min, longer duration of deflation was associated with a decreased frequency of neurologic complications (P = 0.048). We conclude that the likelihood of neurologic dysfunction increases with total tourniquet time and that a reperfusion interval only modestly decreases the risk of nerve injury.

Ten Common Questions (and Their Answers) About Off-label Drug Use

The term off-label drug use (OLDU) is used extensively in the medical literature, continuing medical education exercises, and the media. Yet, we propose that many health care professionals have an underappreciation of its definition, prevalence, and implications. This article introduces and answers 10 questions regarding OLDU in an effort to clarify the practices meaning, breadth of application, acceptance, and liabilities. Off-label drug use involves prescribing medications for indications, or using a dosage or dosage form, that have not been approved by the US Food and Drug Administration. Since the Food and Drug Administration does not regulate the practice of medicine, OLDU has become common. It occurs in every specialty of medicine, but it may be more common in areas of medicine in which the patient population is less likely to be included in clinical trials (eg, pediatric, pregnant, or psychiatric patients). Pharmaceutical companies are not allowed to promote their medications for an off-label use, which has lead to several large settlements for illegal marketing. To limit liability, physicians should prescribe medications only for indications that they believe are in the best interest of the patient. In addition, health care professionals should educate themselves about OLDU to weigh the risks and benefits and provide the best possible care for their patients.

Airway management after failure to intubate by direct laryngoscopy: outcomes in a large teaching hospital

PurposeThe purpose of this single-centre database review was to establish the incidence of failure to intubate by direct laryngoscopy, to measure morbidity and mortality associated with this event, and to examine the use and efficacy of alternative airway devices.MethodsDifficult intubation via direct laryngoscopy at Mayo Clinic Rochester is recorded in an electronic database using a functional classification: 0 = no difficulty; 1 = mild to moderate difficulty; and 2 = severe difficulty often requiring a change in intubation technique. Using this database, the total number of intubations was determined for a selected review period and the incidence of failure to intubate by direct laryngoscopy was established. Abstraction of chart data allowed for determination of associated morbidity and mortality, success of alternative airway devices, and case cancellation rate.ResultsDuring the period from August 1, 2001 through December 31, 2002, 37,482 patients underwent general anesthesia with attempted direct laryngoscopy. One hundred sixty-one patients (0.43%) could not be intubated by direct laryngoscopy alone. Morbidity associated with difficult intubation included soft tissue/ dental damage (n = 8), intraoperative cardiac arrest (n = 1), and possible aspiration (n = 1). Three patients required intensive care unit admission. There was no associated mortality. The most commonly used alternative airway device was the flexible fibreoptic scope. Five case cancellations resulted from failure to intubate with alternative devices.ConclusionThe rate of unexpected failure to intubate by direct laryngoscopy is essentially unchanged from earlier studies. While morbidity was low, continued education and early use of alternative difficult airway devices may further limit complications associated with this event.RésuméObjectifÉtablir, par une revue de la base de données d’un seul centre, la fréquence des échecs à intuber par laryngoscopie directe, mesurer la morbidité et la mortalité associées et vérifier l’usage et l’efficacité d’autres instruments d’intubation.MéthodeLes cas d’intubation difficile par laryngoscopie directe à la clinique Mayo de Rochester ont été notés dans une base de données électronique selon une classification fonctionnelle : 0 = aucune difficulté 1 = difficulté légère à modérée et 2 = difficulté sévère exigeant souvent le recours à d’autres techniques d’intubation. Le nombre total d’intubations a été déterminé pour une période de révision choisie et la fréquence des échecs à intuber par laryngoscopie directe a été établie. Un résumé analytique des données a permis de déterminer la morbidité et la mortalité associées, le succès des autres techniques et le taux d’annulation.RésultatsDu premier août 2001 au 31 décembre 2002, 37 482 patients ont eu une anesthésie générale et subi une laryngoscopie directe. Cent soixante et un patients (0,43 %) n’ont pu être intubés par laryngoscopie directe seulement. La morbidité associée à l’intubation difficile comprenait une lésion des tissus mous/des dents (n = 8), un arrêt cardiaque peropératoire (n = 1) et une aspiration possible (n = 1). Trois patients ont dû être admis à l’unité des soins intensifs. Il n’y a pas eu de mortalité associée. L’instrument de remplacement le plus souvent utilisé a été le fibroscope flexible. Cinq annulations ont résulté de l’échec à intuber avec d’autres instruments.ConclusionLe taux imprévu d’échec à intuber par laryngoscopie directe est essentiellement le même depuis les études antérieures. La morbidité est faible, mais une formation continue et un usage précoce d’autres instruments réduiraient davantage les complications qui y sont associées.

Management of the difficult and failed airway in obstetric anesthesia

Difficulty with airway management in obstetric patients occurs infrequently and failure to secure an airway is rare. A failed airway may result in severe physical and emotional morbidity and possibly death to the mother and baby. Additionally, the family, along with the medical and nursing staff, may face emotional and financial trauma. With the increase in the number of cesarean sections performed under regional anesthesia, the experience and training in performing endotracheal intubations in obstetric anesthesia has decreased. This article reviews the management of the difficult and failed airway in obstetric anesthesia. Underpinning this important topic is the difference between the nonpregnant and pregnant state. Obstetric anatomy and physiology, endotracheal intubation in the obstetric patient, and modifications to the difficult airway algorithms required for obstetric patients will be discussed. We emphasize that decisions regarding airway management must consider the urgency of delivery of the baby. Finally, the need for specific equipment in the obstetric difficult and failed airway is discussed. Worldwide maternal mortality reflects the health of a nation. However, one could also claim that, particularly in Western countries, maternal mortality may reflect the health of the specialty of anesthesia.

Perioperative interscalene blockade: an overview of its history and current clinical use

Use of single-dose and continuous interscalene brachial plexus block (ISB) are gaining widespread popularity. When compared with general anesthesia, ISB has been reported to provide superior postoperative analgesia with fewer side effects, and it is associated with greater patient satisfaction. Anatomical landmarks are readily identifiable, which contributes to the ease of performing this block. In the future, we anticipate increased use of continuous interscalene catheters or injection of biodegradable local anesthetic impregnated microspheres to provide prolonged perioperative outpatient analgesia.

Why brain death is considered death and why there should be no confusion.

Neurologic determination of brain death is a complex assessment that may be misunderstood by nonspecialists and families. Recent guidelines clarify how to proceed with such an examination and are available to physicians, with the time of death in adults and children being determined by the last defining test—the apnea test. This core principle in neurology has been challenged recently in court and resulted in an unprecedented continuation of care in a 13-year-old child declared dead. This review comments on the medical, legal, and ethical quandaries introduced by this case and highlights the major elements of consensus on matters related to brain death that have been forged over 3 decades of sustained medical and societal debate. A clear appreciation by physicians and the public of the diagnostic determination of death following loss of brain function will help to prevent similar conflicts from occurring in the future.

Brain death and the courts

Brain death determinations have been challenged in courts, but no systematic study has been published in the medical literature. Court cases on brain death determination could provide some insights for the clinical practice of physicians. We reviewed legal cases between 1980 and 2010 involving neurologic criteria for death since adoption of the Uniform Determination of Death Act. Court rulings on brain death determination are uncommon, but 2 major themes emerged: consequences of documentation of the time of brain death and family–physician discord on withdrawal of intensive care support. All court rulings upheld the medical practice of death determination using neurologic criteria according to state law, irrespective of other elements of the rulings. Nothing in the court cases suggests a need to alter the current medical standard of brain death determination. Jurisprudence to date emphasizes that the timing and accurate diagnosis of brain death has important weight in the resolution of conflict between practitioners, hospitals, and family members.

Patient and doctor attitudes and beliefs concerning perioperative do not resuscitate orders: anesthesiologists’ growing compliance with patient autonomy and self determination guidelines

BackgroundIn 1993, the American Society of Anesthesiologists (ASA) published guidelines stating that automatic perioperative suspension of Do Not Resuscitate (DNR) orders conflicts with patients’ rights to self-determination. Almost 20 years later, we aimed to explore both patient and doctor views concerning perioperative DNR status.MethodsFive-hundred consecutive patients visiting our preoperative evaluation clinic were surveyed and asked whether they had made decisions regarding resuscitation and to rate their agreement with several statements concerning perioperative resuscitation. Anesthesiologists, surgeons and internists at our tertiary referral institution were also surveyed. They were asked to assess their likelihood of following a hypothetical patient’s DNR status and to rate their level of agreement with a series of non-scenario related statements concerning ethical and practical aspects of perioperative resuscitation.ResultsOver half of patients (57%) agreed that pre-existing DNR requests should be suspended while undergoing a surgical procedure under anesthesia, but 92% believed a discussion between the doctor and patient regarding perioperative resuscitation plans should still occur. Thirty percent of doctors completing the survey believed that DNR orders should automatically be suspended intraoperatively. Anesthesiologists (18%) were significantly less likely to suspend DNR orders than surgeons (38%) or internists (34%) (p < 0.01).ConclusionsAlthough many patients agree that their DNR orders should be suspended for their operation, they expect a discussion regarding the performance and nature of perioperative resuscitation. In contrast to previous studies, anesthesiologists were least likely to automatically suspend a DNR order.

A historical perspective on use of the laryngoscope as a tool in anesthesiology

EACH year, one of the first skills anesthesia residents must master is direct visualization of the vocal cords to safely and successfully intubate the trachea of surgical patients. Debates have raged in teaching centers about the superiority of one laryngoscope over another or the merits of a straight versus a curved blade. However, this yearly debate is a phenomenon of the twentieth century, as anesthesiologists sought better tools to facilitate patient care. Physician interest in visualizing the vocal cords can be traced to at least the mid-1700s. However, controversy remains as to who deserves historical credit for the development of the laryngoscope. An appreciation of the contributions of several innovative scientists involved with the development of the laryngoscope over more than 250 yr may be of greater importance. Although the laryngoscope was initially a tool developed solely for the otolaryngologist, advances in anesthesia during the early 20th century made the addition of the laryngoscope and development of the skills to use it successfully essential to the anesthesiologist. The introduction of the laryngoscope into the practice of clinical anesthesia is best described by considering these advances in the “surgeon” and “anesthesiologist” periods.

Vasotrac arterial blood pressure and direct arterial blood pressure monitoring during liver transplantation.

During liver transplantation two arterial catheters are often placed. The Vasotrac® is a noninvasive monitor that provides radial arterial blood pressures by a tonometric method. We investigated whether the Vasotrac® would be an accurate substitute for an arterial catheter by comparing Vasotrac® blood pressures with simultaneous direct radial blood pressures recorded from the contralateral arm in 14 patients undergoing liver transplantation. Correlation between the two methods was calculated and a Bland-Altman analysis performed to assess agreement. A total of 6468 simultaneous measurements were made over a duration of 1.5–7.5 h per case. For mean arterial blood pressure 57% of Vasotrac® measurements were within 10% of direct arterial measurement. Correlation (r) was 0.82. Vasotrac® bias was +5.4 mm Hg and limits of agreement were ±18.6 mm Hg. For systolic arterial blood pressure 65% of Vasotrac® measurements were within 10% of direct arterial measurement. Correlation was 0.78. Vasotrac® bias was +7.6 mm Hg and limits of agreement ±25 mm Hg. For diastolic arterial blood pressure 57% of Vasotrac® measurements were within 10% of direct arterial measurement. Correlation was 0.82. Vasotrac® bias was +3.3 mm Hg and limits of agreement ±15 mm Hg. We conclude that the Vasotrac® is not adequately accurate to substitute for direct arterial blood pressure monitoring in liver transplantation.