Medicine and Opera

The naiveté of the press when it covers medicine is wondrous. There isn’t any cockamamie nonsense they won’t swallow whole. Katherine Q Seelye has a piece in the New York Times that is about politics. I don’t know much about politics so I can’t comment on most of it. But in discussing the positions of the presidential candidates on universal health care she mentions the “insurance-hospital- pharmaceutical complex”. She appears to think that this nefarious complex has great influence over what happens to medical care.

I immediately asked myself how I could have missed this complex in over half a century of observing all things medical. I knew about the Oedipus complex, the Electra complex, the castration complex (this one may have something to do with politics), the Cassandra complex, the God complex (this may relate to medicine), the inferiority complex the messianic complex (think journalism), the Napoleon complex, the persecution complex, the superiority complex, and a bunch more. But I’d never come across the IHP complex.

Such a sinister and powerful entity implies organization. And if there’s one thing Medicine is not, it’s organized. Only the reality of immediate summary execution might change the way doctors or hospitals operate; it would probably take thousands to overcome the nonsystem’s inertia. And if there’s another thing we’re not, it’s closed mouthed. Even the CIA can keep a secret better than we can. Why do you think the government enacted the HIPAA law? An exercise in futility that any ride on a hospital elevator will prove. Do you think we could keep the IHP complex a secret from everyone but an intrepid investigative reporter? No body is in charge. Don’t worry about conspiracies. The reality is much worse.

So rest easy with the complexes you take to bed every night; there’s not a new one to worry about. Ms Seelye can keep this one for her very own.

The pdf file below contains a detailed review of Cisplatin Nephrotoxicity that we published the the August 2007 issue The American Journal of the Medical Sciences.

cisplatin-nephrotoxicity

A recent report considers how physicians should triage patients in the event of a sudden catastrophe that overwhelms the medical system. “The suggested list was compiled by a task force whose members come from prestigious universities, medical groups, the military and government agencies. They include the Department of Homeland Security, the Centers for Disease Control and Prevention and the Department of Health and Human Services.”

The full report was published in the May 2008 issue of Chest the Journal of the American College of Chest Physicians. Rationing medical care elicits horror whenever the subject is broached, as it should. But if some sudden and overwhelming catastrophe strikes - a pandemic, an overwhelming act of God, an act of war - we will be forced to prioritize the delivery of medical care so that it matches our resources. There would be no choice after these events.

The report includes specific lists of those who should be denied care following a mass disaster:

_People older than 85.

_Those with severe trauma, which could include critical injuries from car crashes and shootings.

_Severely burned patients older than 60.

_Those with severe mental impairment, which could include advanced Alzheimer’s disease.

_Those with a severe chronic disease, such as advanced heart failure, lung disease or poorly controlled diabetes.

This, obviously, is not an all inclusive list. But what if the catastrophe sneaks up on us rather than appearing in an instant? When a boat starts to leak the first impulse is not to abandon ship - women and children last. Medicare, indeed all of medicine, appears to be on the verge of a mass catastrophe that is marching in slow motion. More and more numbers of old and very ill patients require more medical care at ever greater expense with less and less to show for the effort and expense.

Last month I made rounds on a general medicine service. Most of our patients had multiple medical problems that could only be treated at the fringes. We were barely keeping them alive, but at enormous expenditure of money, time and personnel. Everyone was frustrated, patients, their families, doctors, nurses - all were overwhelmed by impossible expectations. Patients who could not be restored to health lingered on for what seemed an eternity and like those around Tolstoy’s Nikolai in Anna Karenina everyone guiltily wished them dead even as they did everything to prolong finished lives. The dying deserve dignity and succor. But we ought to be able to provide them without mortgaging the future.

Dartmouth Medical School is pioneering a new approach to the care of very old patients which seems both humane and less expensive. “Slow Medicine” prompts physicians to consider the benefits that aggressive medical offers to the elderly and to offer more conservative and palliative treatments. Whether it will catch on is uncertain.

Patients who have problems that could be effectively dealt with are either treated as outpatients or are in the hospital for a brief time. Most of the chronically terminal patients we were caring for were over 65. Consider the following data from The Administration on Aging:

The older population–persons 65 years or older–numbered 37.3 million in 2006 (the latest year for which data is available). They represented 12.4% of the U.S. population, about one in every eight Americans. By 2030, there will be about 71.5 million older persons, more than twice their number in 2000. People 65+ represented 12.4% of the population in the year 2000 but are expected to grow to be 20% of the population by 2030.

Absent some medical miracle the number of very old and very sick people in our hospitals will be the equivalent of a sudden overwhelming catastrophe. How will we care for these patients? Who will care for them? How will we afford the expense? Will any one be willing to triage?

I don’t have the answer to any of the questions. But no one seems willing to seriously discuss them much less provide answers. 2030 will arrive with 80 million people on Medicare who will have a lot of chronic (and expensive) medical problems. How will we provide care for them? The needs of such a population are so far beyond our ability to provide them that a retreat to hopelessness is understandable.

Nevertheless, attempts are being made to deal with this impending tsunami of very sick patients. To analyze how this problem will manifest itself requires a book, but here are a few reasons why the problem is even more complicated than it appears.

Medical schools are increasing the size of their classes and new medical schools are under development. This increase in medical graduates is a response to the anticipated increase in demand which results from what I have described above. But there is much less here than meets the eye.

Increasing the number of graduates without increasing the number of residency slots available for them will not increase the number of doctors in practice. There are about 5,000 more first year residency slots available than there are American graduates of American schools. They are currently filled by foreign graduates. Residency positions are mainly paid by Medicare. Medicare is under such financial stress that it is very reluctant to pay for more doctors in training. Increasing the number of American graduates as things now stand will just decrease the number of foreign graduates in residency training.

Medicare can’t pay for the patients it now has. It will soon have to pay for about twice as many more. If we want more doctors to care for them Medicare will have to pay even more.

Another problem that no one talks about is the applicant pool. American medical schools are not deluged with qualified applicants. The national acceptance rate is about 50 %. This is a sharp increase from what it was one or two generations ago. For whatever reason, increasing bureaucracy, increased training time, life style issues, medicine seems to be a less popular career choice than it previously was. With more and more positions available for applicants the quality of those accepted may well decline. Do you want your doctor to be some who went to medical school because he couldn’t get into business or law school?

But even if we do increase the number of high quality graduates and figure out how to pay for them and the costs they generate we still have a problem. More doctors doesn’t result in more hours worked. Rather they work less hours resulting in more doctors who work less hours per week than their predecessors. Thus doubling the number of doctors doesn’t come anywhere near doubling the number of hours worked.

There are at least two reasons for the decrease in hours worked. The first is the life style issue touched on above. Physicians no longer seem willing to work 80 hour weeks. This hardly surprising in an advanced society. The second is that about half of our medical graduates now are women. Women doctors work less hours than men. The reason for this is obvious. They want to have families. And despite almost two generations of nagging the responsibilities of family life fall disproportionally on the wife. Hence women doctors choose branches of the profession which have less time demands, work less hours, and are more likely to take prolonged absences (often years) from work.

But it’s not just more doctors that are wanted. More patients require more nurses, more technicians, more clinics, more hospital beds, many more administrators. And lots more money. More money than we’re likely to have.

A national health plan which seems ever more certain with every new election cycle is not going to increase the desirability of medicine, in my opinion. So how are we going to deal with all these patients. A triage system like the one described above will obviously not do. It probably won’t be accepted even for a nuclear holocaust - at least in advance. The only workable solution seems to be rationing by delay. Affluent patients will buy their way out of the system as they do in Canada (they come to the US) or in the UK (they go to private physicians and hospitals). In other words, a two tiered system, grossly unequal, is likely to result from a desire to provide more or less equal service to all. Cost will be the hammer that builds this system.

I know I said I’d used up my life’s allotment of performances of Donizetti’s bonbon, but Dessay and Florez at the Met was too tempting to pass up. Laurent Pelly’s production moves the opera’s time to that of World War I. But when you set this opera is irrelevant. It succeeds or fails with its title character. Natalie Dessay was as bouncy as a spaldeen. She looked like a combination of Fanny Brice and Edith Piaf on steroids and happy pills. She took over the stage and brought this tired old mish mash to life. Vocally and histrionically she was perfect; forget about a mini-crack. She has a gift for comedy that’s unmatched by any soprano I can think of. When she wasn’t on stage the piece sagged to its proper level - sub par Donizetti, which is still better than almost anyone else. Her performance was one of the rare instances when an artist carries a work far beyond its usual potential. Wonderful. If you were just listening to Dessay’s performance you missed 90% of its impact. She’s truly a singing actress.

There’s a tenor in this opera. Dessay’s star power might have eclipsed a usual tenor, but the estimable Juan Diego Florez managed to be noticed. The current King of the Tenorinos (John Osborn is just as good, but doesn’t have as good a press agent), Florez tossed out the barrel of high Cs at the end of “Pour mon âme” with ostentatious ease. He has repeatedly said that the second act aria, “Pour me rapprocher de Marie” is the harder of the two. And for him it obviously is. Runs and high notes show off his bright and glinty voice. Its hard edge makes singing a long line a little more difficult. He did his best with the second aria, but it was clear he was working hard to make it effective. Osborn did more with the number. Tito Schipa who would have omitted all the high notes (in both acts) would have been perfect for this aria.

Now about the encore of Tonio’s first aria. There wasn’t one. Mr Gelb apparently couldn’t bring himself to press the encore button that travels with him wherever he goes like the nuclear football that follows the President of the US wherever he goes. Florez, who couldn’t have sung the aria any better at the prima than he did on Saturday, was obviously ready for a second launch, but Mission Control refused permission. (I love mixing all these metaphors and similes.) Since everyone was expecting an encore its absence was a real downer. Mr Gelb must have considered the cheering that followed Florez’s performance insufficiently rabid.

The rest of the cast did not get in the way which is all that is required of them. Allessandro Corbelli was appropriately jolly as Sulpice. Felicity Palmer was appropriately stuffy as the Marquise Of Berkenfield. And Marian Seldes was appropriately tottering as the Duchess of Krakenthorp. I wonder if Krakenthorp has some extra meaning in French. Marco Amiliato conducted appropriately.

There were sets and costumes, but if you turned Mme Dessay loose on an empty stage with just a few props the performance would be just as successful as it was with sets and costumes. When she leaves this production there will be little reason to continue it.

Nearly 20% of Veterans who served in Iraq are said to have to have post traumatic stress or major depression according to a study by the Rand Corporation. Everyone seems to be racing ahead of everyone else to embrace these finding lest they be thought negligent or insensitive. A word of caution, though the full report is is available from Rand, no one commenting about it (including me) seems to have read it. And none of the accounts of it I have seen mentions controls.

In order for this study to be meaningful there would have to be at least two control groups similarly studied. One would contain age and sex matched civilians. A second would contain age and sex matched veterans who had not served in a war zone. Absent these controls the finding cannot be adequately interpreted.

Doubtless this study will fill agendas that go beyond health care for veterans. But we can hope that this report was based on adequate information. If I had to bet I would place my wager on the absence of adequate controls.

But even if there were adequate controls the issue of observer bias would still be unresolved. The person doing the psychiatric evaluation will have his own feelings and prejudices about war and military service. These cannot be avoided or suppressed. There’s no way that the evaluator can evaluate without knowing the military history of the subject. Bias no matter how surreptitious will creep into a study like this one. If the study was based on a questionnaire it’s results are even more tenuous.

Studies like this one often excite but far less often inform.

Here’s how the Rand Corp’s web site describes the study:

Data collection for this study began in April 2007 and concluded in January 2008. Specific activities included a critical review of the extant literature on the prevalence of post-traumatic stress disorder, major depression, and traumatic brain injury and their short- and long-term consequences; a population-based survey of servicemembers and veterans who served in Afghanistan or Iraq to assess health status and symptoms, as well as utilization of and barriers to care; a review of existing programs to treat servicemembers and veterans with the three conditions; focus groups with military servicemembers and their spouses; and the development of a microsimulation model to forecast the economic costs of these conditions over time.

It doesn’t sound very reassuring. It seems to be a questionnaire with all the attendant errors such surveys intrinsically contain. It also doesn’t seem to have any controls. You can buy the Rand monograph for $55.50.

Virtually all physicians treat their hypertensive patients who are 80 years old or more. The evidence for the effectiveness of this treatment in very old patients has up till now been lacking. The New England Journal of Medicine has published a paper, Treatment of Hypertension in Patients 80 Years of Age or Older, that shows a benefit of treating hypertension in octogenarians.

The paper claims a little more than it actually demonstrates by pushing some of its conclusion a bit past the usual 5% likelihood of chance typically used in scientific papers. For example, it says that there was a 30% decrease in fatal or nonfatal stroke; p= 0.06.

The patients in the study were all 80 years old or more and had a systolic blood pressure of 160 mm Hg or more. The were randomized into two groups of about 1900 patients each. One group was treated with a placebo while the other received the diuretic indapamide. The treated group also received the angiotensin converting enzyme inhibitor perindopril as needed for additional blood pressure control. The controls received additional placebo.

As can be seen above blood pressure fell more in the treated patients than in controls. But also note that there was a large drop in the blood pressure in the placebo group. Also note the absence of error bars for each point. There was a large standard deviation for each point which would have diluted the case the authors were trying to make, ie that the positive outcomes noted were the result of blood pressure lowering. The paper does not mention if there was a statistically significant difference in the blood pressures between the treated and untreated groups. Instead they say that there was a statistical difference in the number of patient who reached target blood pressure; less than 150 systolic and less than 80 diastolic. Twenty percent of controls reached target blood pressure compared to 48% in the treated group (p<0.001).

Other significant findings in the study were a reduction in all death from stroke and all cause mortality.

The most striking finding, which was of far greater significance both statistically and clinically, was the reduction in heart failure events.

This finding is so important that it alone would justify treating 80 year olds with antihypertensive medicines. But which drugs should the physician use? Here the interpretation of the study gets a little cloudy. Diuretics and ACE inhibitors lower blood pressure. Hypertension is the leading cause of heart failure. So lowering blood pressure should reduce the incidence of heart failure. But these drugs also have a favorable effect on heart failure which goes beyond their effect on blood pressure. It is possible that at least part of the reduction in heart failure events noted in this study is the result of the drugs studied and would not be fully duplicated if blood pressure were lowered to the same degree by drugs of other classes. Thus all one can conclude is that diuretics and ACE inhibitors are beneficial when given to very old hypertensive patients. Whether thiazide diuretics would produce the same result seen with indapamide also is uncertain. All ACE inhibitors seem the same, so I think other ACE inhibitors would be just as effective as perindopril.

Why the authors of this work chose to use indapamide and perindopril which are not as widely prescribed as thiazides and other ACE inhibitors is not clear. It could be related to the study’s sponsor Servier which makes indapamide and perindopril. My guess, but it’s just that, is that thiazides and any ACE inhibitor would produce the same result.

How many times can one watch La Boheme without being bored?. Apparently it is impossible to be bored by any halfway competent performance of Puccini’s masterpiece. Saturday’s HD performance of Zeffirelli’s venerable staging from the Met was better than the minimum level necessary to ward off ennui. It’s been performed so many times at the Met that if the singers and musicians pause for just a moment the production will do the opera on its own. When the show is finally set aside it should be sent to the Smithsonian where it can do La Boheme in an endless loop for the whole world do enjoy on visits to the nation’s capitol.

The performance was certainly worth the $22 price. I wouldn’t have paid $300 for it. Parts of the staging work better on the big screen than in the house. The first and last acts are set in a tiny garret set far back from the front of the stage and very high. In the house the Bohemian’s apartment is too far from the audience for comfortable viewing. On TV there’s no problem as the camera zooms close in. Zeffirelli seems to have taken Yakima Canutt’s staging of the chariot race in Ben Hur as his inspiration for the second act. There were more people onstage than were at all the Iowa caucuses. Here again the big screen was useful.

Angela Gheorghiu was fine as Mimi, though the closeup was not her friend. She’s at an age where she’s got all the voice and experience she needs for the part, but not where she can sustain a point of view a few feet from her face. This would not have been a problem if you were in the auditorium 100 feet from her rather than 2000 miles away. Vocally, she’s got the part down cold.

Ramón Vargas has graduated from bel canto to Puccini without much trouble. He has a lush tenor that is more secure at its top than it was earlier in his career. But his high notes are still a bit tentative. The best singing came from Ludovic Tézier as Marcello. He also acted the part convincingly. I’d like to hear him in a bigger part. Ainhoa Arteta was a vivacious Musetta. Paul Pliska in his 1524th Met appearance was effective as Benoit and almost invisible as Alcindoro in the commotion of Act 2. As a meteorological aside, what were all those people doing outside on Christmas Eve in Paris where the average temperature on that day is about freezing? This issue of temperature is especially noteworthy as the Bohemians spent most of the first act kvetching about how cold it was indoors.

Oren Gardus made almost nothing of Colline’s big moment - the Coat Song. Quinn Kelsey conversely made as much as possible of the sixth Bohemian, Schaunard. Nicola Luisotti who is as breezy as a balloon conucted very well, which is to say you paid little attention to him. All and all, a good show. I suspect that the thousands of people seeing La Boheme for the first time loved it.

Finally, its hard to swallow a story about starving young Parisian proto-hippies who look like poster boys for the metabolic syndrome. Well, two of them did - Vargas and Kelsey.

Giuseppe Di Stefano occupies a special place on the list of the greatest tenors of the last century. I will try to show why with a few examples of his singing that show him at his best.

You will often hear singers and critics admit to admiring the “young” Di Stefano. When you do you are encountering someone who masks confusion and conflict by being patronizing. It’s a response to the tenor’s short period at his peak, barely a decade, in contrast to his long life. No one says they admire the “young” Callas though she was at the top for about the same time as GDS. Ten years of being as great as Di Stefano was is long enough to require no qualifier.

First start with the voice. In its prime it was the most beautiful Italian tenor I ever heard. To my ears even more lush and ravishing than Gigli’s. In his 1951 recording of Che gelida manina the voice was at its pinnacle. The tone is gorgeous. It is not spread or open as it later became. The high note is focused and thrilling. His modulation of the aria’s final word “dir” is one of those small touches that differentiate him from everyone else who has sung the piece. To the beauty of the voice add his ability to find meaning and make great effects in ways that no on else did and you have the combination that made Di Stefano unique.

The quartet (Dunque e proprio finita?) that ends the third act of La Boheme, recorded at the same time as the aria above, shows his distinctive ability to convey meaning and sing pianissimo with full vocal support. “…alla stagion dei fior” is unmatched by any other tenor who’s recorded the number. It’s pure genius.

Di Stefano also set the standard for Cavaradossi in Tosca. His rendition of “E lucevan le stelle” combines both tonal beauty and inimitable phrasing. It speaks for itself. No one has ever made as much of the line “Le belle forme discioglieia dai veli!” as he did.

Mario Del Monaco said Di Stefano was a dramatic tenor in temperament, though not in voice. It was this temperament that made him a great interpreter and which also compelled him to sing roles that his temperament demanded but which prematurely destroyed his voice. Canio in Pagliacci was a role he couldn’t avoid. Though he spent his vocal capital every time he sang the part, he was magnetic as Leoncavallo’s cuckolded clown. The famous aria that concludes the opera’s first act (Recitar!) was never sung with greater effect. While he shouldn’t have sung the spinto parts he added to his repertoire, he wouldn’t have been the artist he was had he been resistant to this temptation. Listen to the opera’s final few minutes - Suvvia cosi terribile . Canio has spent half of the evening trying to learn the name of Nedda’s lover When he does the explosion of his emotion is palpable; no other tenor manages this effect.

Don Alvaro in Verdi’s La Forza Del Destino was another role that put too much strain on his voice. Richard Tucker had the ideal voice for this part. But Di Stefano still managed to add something different to his impersonation of Alvaro. This performance of O tu che in seno agl’angeli from a September 1960 performance in Vienna shows the tenor in remarkably good form considering how far into his vocal decline he was by this time though he was still under forty . Even then he could occasionally come up with something hard to match.

Di Stefano’s diminuendo on the high C in Salut demeure is an extraordinary tour de force. This recording is from a 1950 performance in San Francisco. He was still capable of the effect at the end of 1955 which was when I heard him do it at the old Met. It shows how a singer who was so often criticized for bad vocal technique also possessed a technique that was matchless.

La Favorita was an opera that Di Stefano was made for. This 1949 performance of “Spirto gentil” had to be encored. It displays all of the tenors strengths - the great piano, emotional density, and the lush voice. Alas there is also some openness in the high notes. But so what.

Manon was the Opera in which he made his debut. “Le Reve” displays all his strengths. This performance is from 1948 just two years after his debut. It too was encored. How the 26 year old tenor had reached this level of artistry is unfathomable. Touched by God seems as good an explanation as any.

The world’s most enduring popular songs are those from Naples. Di Stefano sang these songs with the same passion and intensity that he gave to opera. In this repertoire nobody comes close. Everybody sings Core ‘ngrato. Di Stefano recorded the song many times. Here’s an especially good version from a 1950 concert.

It’s human to fully value what you had only after its gone. Pippo’s voice departed almost half a century before its owner left us, but now that both are gone I think that his place among the greatest singers will become clear. I’ve heard many great artists and it’s fruitless to rank them. But when it comes to magic Di Stefano stands alone.

Di Stefano, of course, should have the last word. Listen to the way the emotion changes in the song’s refrain. It defines his art. O sole mio

Addendum: After I posted this piece I received an email asking how I could have been so foolish as to leave out Di Stefano’s 1947 recording of Lamento di Federico. On short reflection I agree it was an egregious omission, so here it is. While I was at it I decided to add two Sicilian folk songs which Pippo sings with such simple beauty that your heart will skip a beat. They’re also from 1947. Cantu a Timuni and A la Barcillunisa.

The purpose of medicine is twofold. First to prolong life, ie to prevent premature death from disease. The second is to relieve pain and suffering from disease. To many medical “experts” it also appears to include the alleviation of just about anything that can cause distress of any sort. War, murder, crime, poverty are among the myriad of mankind’s misfortunes that have been trivialized into diseases. Soon to be a medical problem is the anguish of a falling stock portfolio.

This approach to healing is taken in the piece in the New England Journal of Medicine - Guns, Fear, the Constitution, and the Public’s Health. Its by Garen J Wintermute, MD, MPH who is professor of public health and director of the Violence Prevention Center at UC Davis.

The article has nothing to do with medicine, at least as I have defined it above. It an argument in favor of gun control laws. Dr Perlmute’s expertise on the subject seems to involve sneaking around gun shows looking for evidence of illicit sales of weapons. He’s obviously a true believer. He’s committed to a cause; as are all true believers, its merits are irrelevant. He believes. I’m not saying he is wrong, just that he’s not critical.

That guns kill people seems trite. That they should or should not be more or less regulated seems to me to be a political issue that should be debated in those organs created for that purpose and decided by courts and legislatures. That the piece appears in the NEJM says more about the current state of the medical press than it does about gun control.

The article presents a lot of dire sounding statistics that are either unreferenced or which cite a whole book - both are sloppy scientific practices which would never be tolerated in the “real” part of the journal; ie the part that contains the science. The editorial rush to territory not really medical is exemplified by the next article in the same issue of the NEJM; it’s by a lawyer. It discusses the implications the Supreme Court’s upcoming ruling on whether there is an individual right to bears arms given in the second amendment to the US Constitution. There is nothing objectionable in it. It seems to adequately and fairly cover the subject, but what’s it doing in a medical journal? It not as if medicine doesn’t have a full plate without rushing into politics.

Editing a medical journal or practicing medicine conveys no more standing on issues like gun control than that borne by any other citizen. Dr Perlmute, though it hasn’t prevented him from bursting into the medical press, seems to subliminally recognize the futility or inappropriateness of what he’s up to: “It’s unlikely that health care professionals will soon prevent a greater proportion of shooting victims from dying [Does he want to close trauma units? Stop research on gun shot wounds? Stop the spread of trauma units and emergency services?]; rather, we as a society must prevent shooting from occurring in the first place.” Then why doesn’t he run for office or write for the NY Times? Health care professionals of course can prevent people from dying from shootings. We can treat them. They have a disease. It’s called trauma. Dr Perlmute seems so obsessed with guns that he forgets he’s a doctor.

You may think it harmless and a little laughable when doctors puff themselves up with righteous self importance and medicalize anything they don’t like, but there’s more to it than pomposity. The urge to fix thing you don’t really understand more often breaks them. It’s the same impulse that leads to the pursuit of the ideal that worried Isaiah Berlin so much. Gun control is a serious issue and it deserves serious discussion. A medical journal is not the best place for it.

This is a PowerPoint presentation of a talk given at the annual meeting of the Southern Society for Clinical Investigation - February 23, 2008. It can be used for any noncommercial purpose as long as the original source is acknowledged. Also listed below is a pdf file of a paper on the same subject that will shortly be published in The Journal of the American Society of Nephrology.

Bicarbonate Therapy in Severe Metabolic Acidosis.ppt

Bicarbonate Therapy in Severe Metabolic Acidosis.pdf