Letters to the Editor

Pulseoximetric Pseudobradycardia in Ventilated Newborns with Pneumothorax

Clinical recognition of pneumothorax in a ventilated newborn is very difficult, trans- illumination being the only test available for bed side evaluation. We have observed a characteristic pattern of pulse oximetric displays in ventilated newborns with pneumo-thorax. We present two examples to illustrate our clinical observations.

Baby `A' 32 weeks gestation and 1.5 kg neonate was being ventilated for hyaline memberane diseae from Day 1. One Day 2, the disease had worsened requiring high ventilator settings. An abrupt transition in the displayed readings of pulse oximeter was noticed (from baseline tracings of SaO<sub>2</sub> 92-96% and pulse 120-130) with low saturation signal 80% and decleration of the displayed pulse to 80-88. Simulatenous cardiac auscultation revealed the heart rate to be 128/min. Trans- illumination and chest X-ray confirmed a right sided pneumothorax. As soon as the air was evacuated, the pulse displayed (`pseudo-bradycardia') by the pulse oximeter returned to baseline followed by improvement in SaO₂.

Baby `B', a term male neonate was being ventilated for meconium aspiration syndrome. He had a intercostal chest drainage tube (ICDT) on the right side draining air from Day 1. On Day 2, the pulse oximetric `pseudo-bradycardia' sign (as described above) was observed and it was found that the ICDT was blocked with reaccumulation of air on the right side. With the insertion of a new ICDT and letting out of air, the `pseudobradycardia' reverted. Both the babies herein described were normotensive and well perfused until the occurrence of `pseudobradycardia' and required no other therapeutic intervention apart from the evacuation of air.

Conacher et al. observed a characteristic pulse oximetry paradox in adults receiving positive pressure ventilation with the development of emphysema or pneumothorax (low saturation, low amplitude pulse wave and low blood pressure which improved with the interruption of positive pressure ventilation)(1). They have not commented about the displayed pulse rates in their patients. Since our babies were sedated and ventilator dependent we did not try interruption of positive pressure ventilation. The prompt reversal of the `pseudobradycardia' with drainage of pneu-mothorax in baby `A' and the reappearance of it with a blocked ICDT and reaccumulation of air as in baby `B' point to the reliability of this sign in recognition of pneumothorax in ventilated newborns.

This `pulse oximetric pseudobradycardia' sign, we think is a pulse oximetric reflection of the `pulsus paradoxus' resulting from increases in intrathoracic pressure with the pulse oximeter missing out the low amplitude pulse wave signals thereby resulting in the `pseudobradycardia'.

G. Karthikeyan,
Anil Narang,
Neonatal Division, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India.

Reference

1. Conacher ID, Mc Mohan CC. Pathognomonic pulse oximetry paradox. Lancet 1995; 346: 448.

The recent editorial on multidrug resis-tant typhoid in childhood had raised valid concerns about this frightening health problem(1). Are we supposed to rationalize our antibiotic therapy in day to day practice only keeping in mind resistant infections or an effort should be made at grass-root level in treating any infection cautiously with judicious use of antibiotics?

Salmonella infections, whether drug resistant or not are difficult to diagnose before one week in most situations. In children, presentation of typhoid can be non-specific in the beginning and the classical symptoms and signs may not evolve for many days. Respiratory signs and symptoms may predominate and parents visit doctors during the period when localizing features are minimum or absent with resultant empirical management by practitioners. Many times these empirical antibiotics have included cefadroxyl, amoxycillin-clavulanate combination, oral quinolones and even single daily injections of ceftriaxone. Quite oftne one may encounter multiple antibiotic combination (ciprofloxa-cin with tinidazole, to quote one example) with frequent change of drugs. The usual trend observed also is inadequate time given by parents for the prescribed drugs to act with consequent visits to many doctors in search of dramatic relief. Therapy in such situations is again modifed with either addition of more drugs or change to a higher antibiotic.

Investigations are generally not ordered in routine practice, that too in the initial few days of fever without any localizing features. The usual mode of therapy in these circumstances include symptomatic medications, empirical antimalarials and antibiotics. Investigations like blood culture and widal tests are not widely available in many of our rural and outskirts of urban areas where incidence of these infections may be higher due to inadequate sanitary conditions. Even if facilities are available, the predominantly poor population of our country are not able to afford these tests. Compliance with therapy may be poor with higher rate of discontinuation of drugs when parents are not able to meet the cost of expensive medications. No definitive and specific early diagnostic markers are available for enteric fever. These problems are compounded by lack of control over pharmacies where drugs like ciprofloxacin are dispensed over the counter without even authentic allopathic prescriptions. All these factors coupled together subjects the child to an unprecedented, pragmatic and problem-oriented empirical broad spectrum antibiotics with tendency to overtreat. Even if the child has multi drug resistant salmonella typhi infection it may take few days to a week before the patient really gets a diganosis and appropriate management is instituted. By that time the child may be too sick to take chances and may need combination broad-spectrum antibiotics empirically, awaiting culture results.

A significant proportion of children when managed as out patients do become targets of these above mentioned shortcomings but in an institution or hospital, rational management of cases of fever is still possible and can be easily accomplished. If malaria is clinically suspected by any clinician, even today the practice is to begin with chloroquin, though, other antimalarials are readily available and drug resistant malaria cases are also known to occur. Why can't the the same policy be followed by all in treating cases of fever without focus using first line common antibiotics initially, if at all we have to use one? Except in neonates and infants less than three months where protocol management itself is different, in all other settings we should limit the anti-biotic usage. Every case of fever may not need an antibiotic and basic investigations early in the course of fever with regular follow-up to look for localizing signs and features of deterioration would go a long way in rationalizing our overall antibiotic treatment even through outpatient care.

Its is difficult to avoid damage when the storm has already hit the coast and heavy losses are likely unless precautions have been taken in anticipation. In the ensuring years we are likely to face `storms' of many drug resistant infections in epidemic proportions like enteric fever, malaria, drug resistant tuberculosis, drug resistant streptococci and probably many more. Unless we are alert from now itself we may have to pay a heavy price. We should not leave these problems to be tackled only by epidemiologists, neither that such efforts are restricted to only discussions in forums and journals. Sincere efforts should be made at individual level by all of us in rationalizing day to day antibiotic therapy.

K.M. Adhikari,

Department of Pediatrics,

Post, Visakhapatnam 530 005, India.

Reference

1. Bhutta ZA. The challenge of multidrug resistant typhoid in childhood: Current status and prospects for the future. Indian Pediatr 1999; 36: 129-131.

Dr. Adhikari has rightly pointed out the close relationship between prescribing practices, antibiotics usage and emergence of antimicrobial resistance. The recent trends of drugs resistance in Salmonella typhi and Sal

monella paratyphi have also mirrored widespread antibiotic usage at a primary care level. Notwithstanding the limitations of resources and diagnostic facilities, if urgent measures are not undertaken to regulate antimicrobial availability and prescribing, we may well approach the new millennium with the spectre of potentially untreatable organisms looming ahead(1).

I would however, differ with the approach suggested by Dr. Adhikari of treating all typhoid cases initially with first line agents. Given the fact that in many parts of South Asia, sensitive strains of S. typhi exist in parallel with multidrug resistant (MDR) isolates(2), the proportion of infections with both types of S. typhi isolates may be similar. Waiting for lack of clinical response before instituting second line therapy may be dangerous, as MDR infections are recognized to be more virulent and associated with significantly greater morbidity and mortality, especially if the diagnosis is delayed(3,4).

We believe however, that the same principles can be used to triage patients to either first or second-line therapy. To illustrate, a clinical morbidity score has been developed and validated(5,6) which can successfully pick up MDR typhoid with a sensitivity of 90% and a specificity of 70%(7). It may therefore be possible to train first level health workers and family physicians to institute appropriate antimicrobial therapy, making the diagnosis and management of typhoid more rational. A community-based trial to evaluate the efficacy of such an approach is currently underway in Karachi.

Zulfiqar Ahmed Bhutta,

Professor of Child Health,

e-mail: zulfiqar.bhutta@aku.edu

References

1. Bhutta ZA. The real millennium bugs: The challenge of emerging antimicrobial resistance in Pakistan. J Coll Phys Surg Pakistan 1999; 9: 117-119.

2. Jesudason MV, John R, John TJ. The concurrent prevalence of chloramphenicol-sensitive and multidrug resistant Salmonella typhi in Vellore, S. India. Epidemiol Infect 1996; 116: 225-227.

3. Bhutta ZA. Typhoid fever: Impact of age and drug resistance on mortaity. Arch Dis Child 1996; 75: 214-217.

4. Wain J, Diep TS, Ho VA, Walsh AM, Hoa NT, Parry CM, et al. Quantitation of bacteria in blood of typhoid fever patients and relationship between counts and clinical features, transmis sibility and antibiotic resistance. J. Clin Microbiol 1998; 36: 1683-1687.

5. Bhutta ZA, Khan IA, Molla AM. Therapy of multidrug resistant typhoid fever with oral cefixime vs intravenous ceftriaxone. Pediatr Infect Dis J. 1994; 13: 990-994.

6. Bhutta ZA, Mansoorali N, Hussain R. Plasma cytokines in pediatric typhoidal salmonellosis: correlation with clinical course and outcome. J Infection 1997; 35: 253-256.

7. Bhutta ZA. Community-based management of multidrug-resistant typhoid fever in childhood: A suggested algorithmic approach. Abstracts of the Symposium on Typhoid Fever and the Role of Cefixime, Sixth Western Pacific Congree of Chemotherapy and Infectious Diseases, Kuala Lumpur, Malaysia, November 1998; p 7.

Is it Possible to Achieve Hundred Per cent Vaccinaton Coverage for Children Below 5 Years of Age?

Vaccine prevntable diseases often outbreak in periurban localities and in slums because of poor immuniation coverage. The target to achieve 80-100% vaccination coverage by 2000 A.D. appears a distant goal even with extensive and intensive immunization programs. To see the effect of intensive vaccination service on the immunization status of a periurban locality named Rasoolpur in Gorakhpur, we conducted a samll study. There is a state urban health sub-centre in this area. Ten local girls were selected and trained for household survey in the area with the help of State Urban Development Authority (SUDA), Lucknow. These girls were educated uptok Intermediate. The base-line survey was done in May 1995 using a pretested proforma to know the demography of population and vaccination status of children below 5 years of age. During household survey, efforts were made to interview both the parents and caretakers and to see all the relevant records, immunization cards, prescriptions, etc. Then a free vaccination programme was started on every Sunday between 8-11 a.m. from June 1995 onwards using the locally recruited girls as local resource and door to door visits. Local leaders, teachers and interested people from the area were also actively involved for this program. This program continued as such for one year (May 1996). A repeat survey was done by the girls using the same proforma to assess any change on immunization status after six months and 12 months of intervention.

This locality consisted of a population of 5061 with 2696 males (52%) and 2415 females (48%). The population of under fives was 756 (15.1%) and that of pregnant women was 44 (.9%). Overall literacy status of the area was 56.7% and the female literacy status was 52.6%. The baseline immunization status in this locality for the complete vaccination as recommended by National immunization programe(1) was only 26%. It further showed 30%, 34%, 34% and 28% children had received BCG, DPT(3 doses), OPV (3 doses) and measles vaccine and 10% mothers had received TT. The repeat survey after one year of intensive intervention showed that the immunization status of children had improved only upto 75% and that of pregnant monthers only to 40%. The status of specific vaccines, namely, BCG, DPT, OPV and measles were 75%, 75%, 75% and 80%, respectively after one year of intervention.

The report of Government of india (1995-96) showed the vaccination coverage of all children for BCG, OPV, DPT and measles as 83.7%, 76.8%, 76,4% and 67.8%, respectively(2).

Since we took a small locality with a large number of actively involved volunteers for vaccination which continued every Sunday for one year, we expected 100% coverage. But the results showed a low coverage largely because of the fact that people in slums are still afraid of such an important national program and their fears are not easily corrected even by locally educated and interested volunteers. This study shows the close link between literacy and economic status of people and their participation in health programmes.

B.B. Gupta,

K.P. Kushwaha,

Buxipur, Gorakhpur 273 001, U.P.,

India.

References

1. Program Intervention/Immunization on Cold Chain. National Child Survival and Safe Motherhood Program, MCH Division, Ministry of Health and Family Welfare, Government of India, 1994; p 4.

2. Annual Report 1995-96. Ministry of Health and Family Welfare, Government of India. New Delhi, Government of India Press, 1996; p 29.

Glass syringes are virtually obsolete these days. Take any hospital, nursing home; clinic chemist's shop or a laboratory the syringes and needles used are disposables. Not only in the urban areas, the chemists' shops/clinics siutated in remote rural areas are using these needles and syringes. How many of them are crushed with a plier and disposed off carefully? On the contrary, some are thrown

carelessly in and around a dustbin till a cleaner comes the next day to collect the "garbage" with his hands and throw them at some nearby municipal dumping site. Some are re-used by unlawful means, while others are ignorantly picked up to be re-used in pinning up some papers, e.g., the medical records. In all these processes the handlers have good chances of receiving pricks from these used needles. Single prick of such contaminated needles can transmit the lethal HIV and Hepatitis viruses.

We talk of screening of blood donors, safe sex and avoiding the sharing of needles as preventive strategies of HIV transmission but ignore the safe disposal of disposable needles. It may be difficult to assess the quntum of transmission through this route, but it is an area which requires emphasis and public awareness in primary prevention of the deadly blood borne diseases.

Rekha Harish,
Assistant Professor,
Department of Pediatrics,
Government Medical College,
Jammu, India.