Casey D. Blitt

practice Guidelines for Management of the Difficult airway An Updated Report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway

RACTICE Guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open-forum commentary, and clinical feasibility data. This document updates the “Practice Guidelines for Management of the Difficult Airway: An Updated Report by

Practice Guidelines for Central Venous Access A Report by the American Society of Anesthesiologists Task Force on Central Venous Access

P RACTICE Guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints, and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open forum commentary, and clinical feasibility data.

Relative importance of alpha and beta adrenergic receptors during resuscitation.

Successful resuscitation from cardiac arrest in the asphyxiated dog model has been ascribed to the use of artificial ventilation, closed chest cardiac massage, and administration of a vasopressor. Controversy remains over whether the most commonly employed vasopressor, epinephrine, exerts its effects primarily by elevating diastolic pressure and reestablishing coronary flow, or by exciting cardiac pacemaker cells and enhancing myocardial contractility. To observe pure alpha and beta adrenergic receptor influences during resuscitation, three groups (alpha-blocked, beta-blocked, unblocked) of dogs were studied. beta-blocked dogs resuscitated with phenylephrine and unblocked dogs resuscitated with epinephrine experienced 100% successful resumption of spontaneous circulation after 5 min of asphyxia-induced arrest. Only 27% of alpha-blocked animals resuscitated with isoproterenol were successfully revived. The appearance of the ECG during cardiac arrest and resuscitation could in no way be used to predict the outcome of resuscitation attempts. Results suggest that, initially, alpha receptor stimulation with concomitant diastolic pressure elevation is more important to the success of resuscitation than beta receptor stimulation.

Mechanism of action of epinephrine in resuscitation from asphyxial arrest.

To determine the relative importance of the alpha and beta adrenergic effects of epinephrine in resuscitation, 32 dogs were studied in four groups. Group A (α blocked) received phenoxybenzamine, 70 mg/kg; group B (β blocked), propranolol 5 mg/kg; group C (α and β blocked) both drugs; and group D (control), no drug. After this treatment and 5 min of asphyxial arrest, all animals received closed chest cardiac massage (CCCM), artificial ventilation (AR), and epinephrine, 1 mg, iv. Resumption of spontaneous circulation occurred with the following frequency: group A, 0/8; group B, 6/8, group C, 0/8; group D, 7/8. The difference in successful resuscitation of the alpha blocked animals and the not alpha blocked animals is statistically significant (p ≤ 0.01). It is concluded that the efficacy of epinephrine in aiding resumption of spontaneous circulation from asphyxial arrest is due to alpha adrenergic receptor stimulation and that beta receptor stimulation is not important in determining outcome.

Silent regurgitation and aspiration during general anesthesia.

URING anesthesia, vomiting need not D be obvious for gastric material to enter the respiratory tract.lz2 In 1949, Weiss3 and, in 1951, Culver and associates4 investigated the incidence of “silent” regurgitation under inhalation anesthesia in a small series of unselected surgical patients. Both studies revealed a 26 percent incidence of regurgitation. Of those patients regurgitating, 76 percent in the former and 62 percent in the latter study also aspirated. In 1953, Berson and Adrianij made observations on a total of 926 patients scheduled for elective surgical procedures, finding an overall incidence of 14 percent regurgitation. About half of those regurgitating also aspirated.

Monitoring in anesthesia and critical care medicine

Part 1 General principles: a philosophy of monitoring the senses as monitors precordial and esophageal stethoscopes monitoring and patient safety cost benefit analysis on monitoring. Part 2 Cardiovascular system: noninvasive blood pressure monitoring invasive blood pressure monitoring electrocardiographic monitoring central venous pressure monitoring the Swan-Ganz catheter - past and present pulmonary artery catheterization transesophageal data collection. Part 3 Monitoring the respiratory system: respiratory monitoring monitoring anesthetic and respiratory gases blood gas monitoring pulse oximetry. Part 4 Monitoring and the central nervous system: the electroenecephalogram evoked potential monitoring monitoring intracranial pressure. Part 5 Miscellaneous monitoring: temperature monitoring monitoring the kidney and urine miscellaneous blood measurements monitoring the anesthetic delivery system monitoring the neuromuscular junction the computer in anesthesia monitoring in unusual environments. Part 6 Monitoring and subspecialities: monitoring in neuroanesthesia monitoring in cardia anesthesia monitoring in the pediatric patient monitoring in obstetric anesthesia monitoring in the intensive care setting monitoring modalitites of the future.

Comparison of bupivacaine, etidocaine, and saline for trigger-point therapy.

Injections of local anesthetics, saline, “dry needling,” or other stimuli at specific, tender loci (trigger or acupuncture points) are reportedly efficacious in treatment of chronic pain syndromes. In a randomized, double-blind crossover study, subjective responses of 15 patients with myofascial syndrome to trigger-point injections of either bupivacaine 0.5%, etidocaine 1%, or physiologic saline without preservative were compared. Responses in six pain-related categories were determined before treatment and 15 minutes, 24 hours, and 7 days after treatment. Trigger-point injections with bupivacaine and etidocaine were generally preferred over saline in several pain-related categories. Implications and possible mechanisms are discussed.

Enflurane-Induced Central Nervous System Excitation and Its Relation to Carbon Dioxide Tension

In our clinical evaluation of enflurane, muscular twitching was observed in 7 percent of the patients.3 Two lead scalp elmtroencephalographic (EEG) recordings during surgical procedures showed intermittent spiking activity at burst-suppression levels of anesthesia. Depth EEG recordings from 4 patients with temporal-lobe electrode implants showed generalized spiking activity that increased in magnitude during hyperventilation. However, it was still unclear whether the spiking activity was induced solely by enflurane or was a manifestation of the induced hypocapnia. In this study we correlated depth EEG activity with changes in the alveolar concentration of both enflurane and carbon dioxide (CO,) to determine the effects of anesthetic depth and C 0 2 levels upon the central nervous system excitation produced by this drug.

Comparison of dopamine, dobutamine, and epinephrine in CPR.

Two new catecholamines, dopamine and dobutamine, have found widespread use for cardiovascular support. The relative efficacy of these drugs in aiding resuscitation from cardiopulmonary arrest is unknown. Dogs were subjected to either asphyxial or fibrillatory cardiac arrest. Resuscitation was attempted with artificial ventilation, closed chest cardiac massage, and one of four iv drug protocols: dopamine, 40 mg; epinephrine, 1 mg; dobutamine, 50 mg; or no drug. The incidence of successful resuscitation from both asphyxial and fibrillatory arrest was significantly greater in groups receiving dopamine or epinephrine than in groups receiving dobutamine or no drug. There was no difference in success between the dopamine and epinephrine groups.The authors conclude that, in dogs, dopamine is a useful adjunct to CPR because of its α-adrenergic stimulating activity at high doses. Dobutamine does not appear to be of value as the initial therapy of cardiac arrest. If the response in man is similar to that in dogs, dopamine may provide an alternative to epinephrine during CPR.

Correlation of Plasma Cholinesterase Activity and Duration of Action of Succinyicholine During Pregnancy

Correlation between plasma cholinesterase activity and duration of neuromuscular blockade following succinylcholine (SCh) was studied in 30 healthy women undergoing laparoscopictubal coagulation and 20 pregnant women undergoing elective repeat cesarean section. All patients received N2O-thiopental anesthesia. Cholinesterase activity in nonpregnant patients was significantly greater than in pregnant patients. Time to 90 percent recovery of control twitch height following 40 or 80 mg/m2 BSA of SCh was not significantly different in pregnant versus nonpregnant patients. There also was no correlation between plasma cholinesterase activity and duration of paralysis from SCh. The authors conclude that pregnant patients have lower cholinesterase activity, but prolonged neuromuscular blockade from SCh should not occur unless the patient is grossly overdosed with SCh. Routine use of a peripheral nerve stimulator is recommended to avoid such overdosage.