Sukumar P. Desai

A clinical sign to predict difficult tracheal intubation; a prospective study

It has been suggested that the size of the base of the tongue is an important factor determining the degree of difficulty of direct laryngoscopy. A relatively simple grading system which involves preoperative ability to visualize the faucial pillars, soft palate and base of uvula was designed as a means of predicting the degree of difficulty in laryngeal exposure. The system was evaluated in 210 patients. The degree of difficulty in visualizing these three structures was an accurate predictor of difficulty with direct laryngoscopy (p < 0,001).RésuméIl a été suggéré que la grosseur de la base de la langue est un facteur important dans la détermination du degré de difficulté de la laryngoscopie directe. Un système relativement simple de classification impliquant la capacité pré-opératoire de visualiser les piliers du voile du palais, le voile du palais et la base de la luette a été conçu afin de prédire le degré de la difficulté d’ exposition du larynx. Ce système a été évalué chez 210 patients. On a trouvé que le degré de difficulté encourue lors de la visualisation de ces trois structures était un moyen précis pour prédire la difficulté de la laryngoscopie directe (p < 0.001).

Neurologic and histopathologic evaluation after high-volume intrathecal amitriptyline

Background and objectives Accumulating evidence indicates that amitriptyline decreases pain sensation when administered orally, intraperitoneally, or for sciatic nerve block. Previous reports of intrathecal administration of amitriptyline have yielded inconsistent results. The failure of amitriptyline to provide antinociception may partly be related to its high logP (octanol-water partition coefficient) and consequent poor spread within the cerebrospinal fluid. We evaluated spinal block after various concentrations of amitriptyline administered intrathecally in a fixed high volume. Methods We administered 100 μL of 5, 10, 15.9 (0.5%), 25, 50, or 100 mmol/L amitriptyline hydrochloride solution or 100 μL of 15.4 mmol/L (0.5%) bupivacaine hydrochloride solution intrathecally to rats. The neurologic deficit was evaluated by antinociceptive, motor, and proprioceptive responses, and the spinal cord was examined for histopathologic changes. Results Doses of 100 μL amitriptyline at 15.9 mmol/L (0.5%) and 25 mmol/L produced longer complete nerve block than did bupivacaine at 15.4 mmol/L (0.5%); 5 and 10 mmol/L amitriptyline produced only partial nerve block. However, with 100 μL intrathecal amitriptyline at 50 and 100 mmol/L, many rats did not fully recover from spinal block. Severe axonal degeneration, myelin breakdown, and replacement of neuronal structures by vacuoles were seen in the spinal root section of animals injected with concentrations higher than 25 mmol/L amitriptyline. Conclusions At lower doses, intrathecal injection of high volumes of amitriptyline results in long-acting spinal block. At higher doses, intrathecal amitriptyline results in irreversible neurologic deficit. Therefore, we do not recommend the use of intrathecal amitriptyline because of a very low therapeutic index.

History of anesthesia for ambulatory surgery.

Purpose of review Anesthesia for ambulatory surgery has come a long way since 1842 when James Venable underwent surgery for removal of a neck mass with Crawford W. Long administering ether and also being the surgeon. We examine major advances over the past century and a half. Recent findings The development of anesthesia as a medical specialty is perhaps the single most important improvement that has enabled advances in the surgical specialties. Moreover, improved equipment, monitoring, training, evaluation of patients, discovery of better anesthetic agents, pain control, and the evolution of perioperative care are the main reasons why ambulatory anesthesia remains so safe in modern times. The development of less invasive surgical techniques, economic factors, and patient preferences provided addition impetus to the popularity of ambulatory surgery. Summary Beyond the discovery in the mid-19th century that ether and nitrous oxide could be used to render patients unconscious during surgical procedures, subsequent developments in our specialty have added modestly, in a stepwise manner, to reduce mortality and morbidity associated with its use. These improvements have allowed us to safely meet the steadily increasing demand for ambulatory surgery.

Acute Pulmonary Edema during Laparoscopy

Laparoscopy is a frequently performed gynecologic procedure. Despi te the stress of insufflation of several liters of carbon dioxide or nitrous oxide a n d extreme Trendelenburg position, few cardiorespiratory anesthetic complications have been reported. Unexplained cardiovascular collapse resulting i n death i n clinically healthy patients during laparoscopy is a n extremely rare but tragic occurrence. A case of acute fulminant pulmonary edema short ly after insufflation for laparoscopy in a young patient without known cardiopulmonary disease is described in this report.

History of anaesthesia: Amedeo Avogadro (1776-1856) - Do his accomplishments match his reputation?

The name of Italian scientist Amedeo Avogadro (1776– 1856) is associated with two fundamental laws in chemistry. The first states that 1 mol of every gas occupies 22.4 l at standard temperature and pressure; the second affirms that 1 mol of every substance has the same number of molecules (6.02 10), a value referred to as Avogadro’s number. We examine how these principles came to be associated with his name and the many incremental contributions made by several other European scientists in the 19th and 20th Centuries in this field. We provide examples of not only how these principles enhance our understanding of the behaviour of gases but also how they are applied in modern clinical anaesthesia.

Prolonged neuromuscular blockade with atracurium

During general anaesthesia with oxygen, nitrous oxide and enflurane, a 29-year-old woman received a total of 105 mg (1.78mg.kg-1) of atracurium over a 2.5 hour period. The neuromuscular blockade could not be completely reversed with neostigmine and mechanical venti-latory support was necessary for three hours postopera-tively. The patient received succinylcholine without unusual sequelae before and after this episode. This is the first report of a patient who exhibited prolonged weakness after receiving atracurium.RésuméLors de I’anesthésie générate avec oxygène, protoxide d’azote et enflurane, une femme ôgée de 29 ans a reçu une dose totale de 105 mg (1.78mg.kg-1) d’atracurium pour une période de 2.5 heures. Le blocage neuromusculaire ne pouvait être renversé avec la neostigmine et la ventilation mécanique était nécessaire pour une période de trois heures post-opératoire. La patiente a reçu de la succinylchoUne sans aucune séquelle avant et après cette épisode. Ceci est le premier rapport sur une patiente ayant démontré une faiblesse prolongée après avoir regu I’atracurium.

The Use of Transcranial Magnetic Stimulation for Monitoring Descending Spinal Cord Motor Function

This report describes our initial clinical experience using transcranial magnetic stimulation for monitoring spinal cord motor function during surgical procedures. Motor evoked potentials were elicited using a cap shaped coil placed on the scalp of 27 patients while recording peripheral motor responses (compound muscle action potentials – CMAPs) from the upper (N=1) or lower limbs (N=26). Wherever possible, cortical somatosensory responses (SEPs) were also monitored by electrically stimulating the left and right posterior tibial nerve (N=25) or the median nerve (N=1). The judicious choice of anesthetic regimens resulted in successfully obtaining motor evoked responses (MEPs) in 21 of 27 patients and SEPs in 26 of 27 patients. Single pulse TMS resulted in peripheral muscle responses having large variability, whereas, the variability of SEPs was much less. Criteria based on response variability for assessing clinically significant changes in both MEPs and SEPs resulted in two false negative predictions for SEPs and none for MEPs when evaluating postoperative motor function. We recommend monitoring both sensory and motor pathways during procedures where placing the spinal cord at risk of damage.

Plasma amino acid concentrations during branched-chain amino acid infusions in stressed patients.

To determine the effect of infusing large quantities of BCAA on plasma amino acid concentrations, plasma amino acid profiles were measured in 18 stressed patients before and 48 to 96 hours after initiation of amino acid solutions enriched with or exclusively containing BCAA (15.6+, 50%, 100%). Plasma concentrations of BCAA were elevated in the 100% and 50% BCAA groups, but not in the 15.6% group. Methionine, glycine, and phenylalanine concentrations were increased in the 15.6% BCAA group: methionine and glycine were decreased in the 100% BCAA groups. In the 50% BCAA group, nonbranched-chain amino acids maintained baseline concentrations. The 50% solution best preserved nitrogen balance of the BCAA solutions. The plasma amino acid profiles of patients with maple syrup urine disease (BCAA levels 5 to 10 times normal) were compared to our patients receiving BCAA-enriched solutions. Although plasma BCAA levels were elevated in our patients, allo-isoleucine, alanine, and glutamine concentrations were normal; the amino acid abnormalities of maple syrup urine disease were not observed.

Lidocaine inhibits NIH-3T3 cell multiplication by increasing the expression of cyclin-dependent kinase inhibitor 1A (p21).

BACKGROUND: We explored molecular mechanisms by which lidocaine inhibits growth in the murine embryonic fibroblast cell line NIH-3T3. Local anesthetics can adversely affect cell growth in vitro. Their effects on wound healing are controversial. We examined the effects and novel mechanisms by which lidocaine affects in vitro multiplication of the murine fibroblast cell line NIH-3T3. METHODS: NIH-3T3 cells were grown in culture with lidocaine [0, 0.05, 0.5, 1, 2, and 5 mM]. Cell multiplication was assessed by determining cell counts on subsequent days, while mechanisms by which inhibition occurred were evaluated by bromodeoxyuridine uptake, gene expression using polymerase chain reaction array, and Western blot analysis to verify increased levels of affected proteins. RESULTS: Lidocaine caused dose-dependent inhibition of multiplication of NIH-3T3 cells. Effects ranged from no inhibition [0.05 and 0.5 mM] and mild inhibition [1 mM], to severe inhibition [2 and 5 mM] [P = 0.006]. Lidocaine 2 mM inhibited bromodeoxyuridine uptake at day 3.5 [P = 0.02 versus control, and P = 0.0495 vs 1 mM lidocaine]. On day 1.5, lidocaine upregulated expression of cyclin-D1 and cyclin-dependent kinase inhibitor 1A [p21]. On day 2.5, lidocaine increased the levels of p21 protein. CONCLUSIONS: Low concentrations of lidocaine, as would be seen in plasma after spinal, epidural, or plexus anesthesia, do not significantly affect multiplication of fibroblasts. Higher doses of lidocaine arrest cell multiplication at the S-phase of the growth cycle by upregulation of p21, an extremely potent inhibitor of cell multiplication. Higher concentrations, as would be seen after tissue infiltration, severely inhibit fibroblast multiplication and thus may impair wound healing.

Contributions of ancient Indian physicians--implications for modern times

Ayurveda traces its origins to contributions of mythological and real physicians that lived millennia earlier. In many respects, Western medicine also had similar origins and beliefs, however, the introduction of anatomical dissection and progressive application of scientific evidence based practices have resulted in divergent paths taken by these systems. We examined the lives, careers, and contributions made by nine ancient Indian physicians. Ancient texts, translations of these texts, books, and biographical works were consulted to obtain relevant information, both for Indian traditional medicine as well as for Western medicine. Ayurveda has retained principles enunciated by these physicians, with minor conceptual advances over the centuries. Western medicine separated from ancient Indian medicine several hundred years ago, and remains the foundation of modern medicine. Modern medicine is evidence based, and randomized clinical trials (RCTs) are the gold standard by which efficacy of treatment is evaluated. Ayurvedic medicine has not undergone such critical evaluation to any large extent. The few RCTs that have evaluated alternative medical treatment recently have shown that such therapy is no better than placebo; however, placebo treatment is 30% effective. We suggest that foreign domination, initially by Mughals, and later by the British, may have contributed, in part, to this inertia and protracted status quo.