Sir,
We read with great interest the article “Morbidly obese parturient: Challenges for the anaesthesiologist, including managing the difficult airway in obstetrics. What is new?” by Rao and Rao.[1] However, there are certain points which need further discussion.
Foetal dose with conventional chest X-ray is is less than 0.01 mGy. Even then, diagnostic radiological procedures should be performed during pregnancy only if the information to be gained from the study is necessary for the care of the patient as per the American College of Obstetricians and Gynecologists (ACOG) Committee Opinion.[2] Pulmonary function test would be more ideal for the preoperative assessment of degree of restrictive lung disease in obese parturient.
Beta blockers are classified as category C as per the US Food and Drug Administration (FDA) classification, which means that animal studies have revealed adverse foetal effects, but there are no controlled data in women. Potential maternal benefit must always be weighed against the foetal side effects.[3] If beta blockers are prescribed, it is recommended to monitor foetal heart rate and intrauterine growth. They should be discontinued before labour. After delivery, monitoring of neonatal heart rate, respiratory status and blood sugar is essential.
The Abe formula [lumbar puncture depth (cm) = 1 + 17 weight (kg)/height (cm)] might be a more reliable predictor for estimating the required LP needle length.[4] It is prudent to select a longer needle for an obese patient if the formula calculates a depth that is barely within the range of the needle at hand to reduce the number of attempts and patient discomfort.
REFERENCES
- 1.Rao DP, Rao VA. Morbidly obese parturient: Challenges for the anaesthesiologist, including managing the diffi cult airway in obstetrics. What is new? Indian J Anaesth. 2010;54:508–21. doi: 10.4103/0019-5049.72639. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.ACOG Committee on Obstetric Practice. American College of Obstetricians and Gynecologists Committee Opinion #299, September 2004 (replaces No. 158, September 1995). Guidelines for Diagnostic Imaging During Pregnancy. Obstet Gynecol. 2004;104:647–51. doi: 10.1097/00006250-200409000-00053. [DOI] [PubMed] [Google Scholar]
- 3.Libby P. Braunwald E, Libby: Braunwald's Heart Disease: A textbook Of Cardiovascular Medicine. 8th edition. Philadelphia: Saunders Elsevier; 2008. Pregnancy and heart disease., 8th edition, Philadelphia: Saunders Elsevier; 2008; p. 1976. [Google Scholar]
- 4.Abe KK, Yamamoto LG, Jtoman EM, Nakasone TA, Kanayama SK. Lumbar puncture needle length determination. Am J Emerg Med. 2005;23:742–46. doi: 10.1016/j.ajem.2005.03.012. [DOI] [PubMed] [Google Scholar]