Letters to the Editor
REPLY Dear Editor. e would like to thank the authors for their comments and suggestion. Their contention is well considered and accepted. We would however justify the concentration and volume of anaesthetic mixture used by us because of the following reasons: (a) Both our patients, apart from the dominant limb injuries. had associated injuries elsewhere. Local infiltration was therefore required for their debridement besides the plexus blocks. To limit the total dose to below toxic levels. we did not employ the maximum permissible doses for the block alone. (b) A study done by SChnorr on 131 anaesthsiologists routinely using regional anaesthesia addressed their preferences regarding use of drug mixtures and the reasons thereof. As many as 70% respondents employed local anaesthetic mixtures. The rationale for USe was to combine benefits and avoid individual toxicity by limiting the dosage of the parent compounds to near two thirds of permissible limit Pl. Lr Col Bhot's typical example quoted, apparently for an adult, depicts the use of maximum permissible doses of both bupivacaine and lignocaine employed in combination. Thus. not only are the benefits of reducing individual drug toxicity negated by this approach, the risk is in fact increased.
(c) Drug interactions in LA mixtures are unpredictable and do not follow a mathematical linear progression. Higher drug concentration with smaller volume is advocated by some authors for plexus block. which can result in local and systemic toxicity . We rely on using larger volumes in dilution. This not only offsets the need
for very accurate needle placement but also has an added advantage of limiting the dose of individual drug. We have used this method in 80 patients of extremity trauma with successful results 13). (d) Though employed in dilution, it is pertinent to mention thai 5% lignocaine causes irreversible nerve damage in animal studies and is infact employed as a neurolytic agent [41. I would like to put on record my gratefulness and appreciation of Lt Col FB Shot. christened the 'Raja of Regionals ' by his trainees. I have learned regional block techniques from him which have proved to be of immense utility in emergency situations. References I. Schnorr C. Menges T. Hempelmann G. Local anesthet ic mixtures in various regional anaesthesia procedures . Anasth Imensivther Notfall med 1990;25(3):193-7. 2. Halford FJ. A critique of IV anaesthesia in war surgery. Anaesthesiology. 1943:4:67-9.
3. Mehrotra S. Mehrotra M. Regiona l block anaesthesia how effective is it for extremity trauma? MlAFI 2002 ;58(3):205-9. 4. Dook IL. Jeong lY. Kim KS. Neurolytic blockade with 5% Lidocaine.J Anaesthesiology Clin Pharmacol. 15;4:393.
Maj S MEHROTRA·, Maj M MEHROTRA + 'Classified Specialist. (Surgery), (on study leave). Department of Reconstructive Surgery. Post Graduate Institute of Medical Sci ences, Chandigarh, "Graded Specialist (Anaesthesiology), 319, Field Ambulance, Clo 56 APO.
HOSPITAl. BEDS IN THE ARMED FORCES Dear Editor,
radiopaque lop. and absence of facility for head low position.
This is with reference to the leiter to Editor titled "Design Modification of the Back Rest of Hospital Beds in the Armed Forces : A Proposal". The backrest of the ordinance supply bed has serious drawbacks in addition to being rendered immobile following repeated painting. These flaws are being listed below: (a) The design of the backrest obstructs access to head and neck region of the patient. This is a serious flaw in the design, which will be well appreciated by a person who is called upon to intubate a patient in an emergency. Valuable time is lost in removing the backrest before laryngoscopy is possible. After removing the backrest. the medicare provider has to position himself under the horizontal bar (which is difficult to remove) before he can attempt laryngoscopy. (b) The additional limitations of the bed design are heavy weight,
These are worth enumerating here to make all medical officers aware that the basic hospital bed has serious design limitations. A hospital bed should be light , easily transportable, have a radioluscent top. provide easy and ready access to head and airway. and should provide facility to give a head low position. Cost constraints may prevent the organization from changing all the available beds everywhere. However, all efforts should be made to position beds which incorporate design features as mentioned in para 4, especially in areas where patients with acute illnesses are
cared. Wg Cdr HARSH VARDHAN·, Wg Cdr S ANANT T '''Classified Specialist (Anaesthesiology), 7 Air Force Hospital.
REPLY Dear Editor.
his is in reply to the comments received with reference to the Letter to the Editor titled "Design Modification of the BackRest of Hospital Beds in the Armed Forces: A Proposal" from Wg Cdr Harsh Vardhan and Wg Cdr S Anant.
I agree with me flaws brought out in the above mentioned comments. However, I would like to offer the following comments/suggestions : (a) The comments reinforce the fact that there is a need to study the usability/functional role of the hospital beds in its entirety and not from tile viewpoint of a medical officer at the periphery or the
speci alist at bigger hospitals. (b) Most of the hospital beds and their design specifications can be divided into those used in acute care/intensive care and chronic care settings. It is obvious that the requirements of acute care would be different from a chronic care patient. This would also explain the requirement of radiolucent chest X-ray top with cassette holder in beds , being used in intensive care settings. It may be wonhwhile to point that the radio-lucent lop is offered as an optional accessory by the manufacturers and does not come as an integral pan of all intensive care beds. (c) With the above in mind, there may not be a single design MJAFI. VOL 58. NO. .~. 2002
Letters to the Editor which would suit the requirements of all patient care / medical unit settings. A consensus could be reached on the basic requirements of a functionally appropriate hospital bed based on a detailed study.
Wg Cdr N TANEJA Classified Specialist (Aerospace Medicine), PHS (on study leave). C/o AFCAO, Subroto Park, New Delhi - 110 010.
PREOPERATIVE BLEEDING TIME AND CLOTTING TIME TESTS :USEFUL OR WASTEFUL? Dear Editor, reoperative Bleeding Time (BT) and Clotting Time (CT) tests are expected to detect occult haemostatic disorders. Conversely it is assumed that normal BT-CT results exclude haemostatic disorders. This presumption is the basis of selecting BT-CT as the screening tests. In our hospital, in two years, 1662 BT and 1713 CT preoperative tests were performed. BT test was performed by modified method and CT by capillary method [I J. No patient had history or clinical findings suggestive of haemostatic disorders. None of the patients suffered from excessive intra or postoperative blood loss that could be attributed to haemostatic disorders. We did not find any abnormal BT or CT result that could indicate haemostatic disorder in these patients. On the contrary, in established cases of haemostatic disorders. BT- cr results were abnormal only when the disorder assumed severe form. Are we justified in relying on BT - cr as preoperative screening tests for haemostatic disorders? Bleeding time lest should be performed by Standard Template Method or Ivy's method. Standardization is very important as even minor deviation like a change in the size ofsphygmomanometer cuff can alter the results. The modified method commonly used in service hospitals [I] is too crude and unreliable for any valuable information. There is no correlation between a skin tempI ale bleeding time, certain visceral bleeding times, preoperative BT results and surgical blood loss or transfusion requirements [2,3]. Trauma to vascular system, not haemostatic disorders, causes most of the perioperative blood loss. Whole blood clotting time measures the time required for formation of the first traces of thrombin sufficient to produce a visible clot. The CT is abnormal only with severe coagulation factors deficiency (as low as 10-15%). It is a poor screening test that seldom provides information not obtained by other more reliable tests. The CT test by capillary method as practised in service hospitals, is highly unreliable [I]. These investigations (BT-CT) are not sensitive screening tests to detect haemostatic disorders [1 J. Their role in preoperative screening is questionable [4-6]. Despite thousands of these tests not a single case of haemostatic disorder was detected in our hospital in preoperative workout. Informal discussions with surgeons, anaesthesiologists and pathologists revealed that in their cumulative experience
of over 100 practicing years not a single asymptomatic case of haernostatic disorder was detected by BT-CT tests. More often than not, these tests are carried out as an empirical legacy. perhaps for completion of medical documents. Our experience and review of literature reveal that BT-CT tests do not fulfill the criteria required for screening tests. Haemostatlc disorders can be easily suspected by history and clinical examination, the first step to diagnosis. A guestimate at the numberofBT-CT tests performed in all service hospitals would be mind-boggling. Are we justified in such colossal waste of time, resources and effort in performing these non-contributory tests? The surgeons, anaesthesiologists and pathologists need 10 ponder over it. The BT-CT tests as routine blind preoperative screening, should be dispensed with. This would require change of perception and attitude. The Senior Advisers perhaps can issue suitable instructions 10 streamline preoperative investigations. The time and resources thus saved can be redirected to more fruitful work.
References I. Laboratory investigation of haernorrhagic and purperic disorders. In : Bbardwaj IR, SwamyGLN,Subramanya H, Nagendra A, Arora MM,
editors. Laboratory Manual of The Anned Forces. Armed Forces MedicalCollege, Pone, India.200t;t:4t-54. Rodgers RPC, Levin I. A critical reappraisal of the bleeding time. SeminThromb Hemost, 1990;16:1. Lind SE. The bleedingtime does nol predict surgical bleeding. Blood 1991;77:2547. Bushick I. Eisenberg I, Kinman I et al. Pursuitof abnormal coagulation screeni ng tests generates modest bidden preoperati ve costs. J Gen InternMed 1989:4:493-7. RohrerMI, Micheloti MC, NahrwoldDL. A prospective evaluation of the efficacyof preoperati ve coagulation testi ng. Ann Surg t988;208: 554-7. Turnbull 1M, Buck C. The value of preoperative screening investigations in otherwise healthy individuals. Arch Intern Med 1987;t47: 1101-5.
Lt Col S GOKHALE Classified Specialist (Pathology & Microbiology). Command Hospital (Central Command), Lucknow-226 002.
RADICAL CURE OF VIVAX MALARIA: 5 OR 14 DAYS Dear Editor, lasmodium vivax malaria accounts for 60-65% of total malaria cases in India. Vivax infections cause significant morbidity since in addition to the primary infection, dormant liver stages (hypnozoites) may re-emerge long after completion of full course of chloroquine treatment (25mglkg) to cause relapses. The relapse patterns of P vivax are broadly divided into the tropical or Chesson strain type characterized by an early primary attack followed by a short latent period. the appearance of frequent relapses and the St. Elizabeth strain of the temperature type by an early primary attack and a long latent period of 6-14 months followed by relapses [I]. Primaquine is the drug used for radical cure of vivax malaria. The National Malaria Eradication Programme of India recom-
MJAFl. VOL 58, NO. J, 1002
mends primaquine in a dose of 15 mg/day for 5 days to all vivax malaria patients, which is also followed in the Armed Forces. WHO while advocating the treatment of malaria including prevention of relapses has categorized population based on their immune status with respect to malaria-immune, semi-immune and non-immune. While they advocate a 5 day primaquine regimen for the first two categories, they recommend a 14 day schedule for the non immune population. For some reasons, we in India have considered ourselves as either immune or semi-immune. Practically speaking, there can be no immune population. Further, immunity in malaria is so diverse on account of strain variation within the same species that a migratory or floating population like the Armed Forces can never be considered immune or semi-immune. It has an appropriate label as