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The contents of this blog are solely meant for information & education purpose only.These may be the basis of actual treatment, but not necessarily. Information from other websites and journals are also included. So the author is not responsible for any inaccuracy,loss, or damage that may arise due to the use of these informations published here. I do respect copyright & always give credits to the original author(s) and thankful to them. Inspite of my utmost effort and care there can be human error. If anyone finds any violation of copyright please inform me at anesthesiatoday@gmail.com and necessary action will be taken soon as possible.
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Wednesday, June 30, 2010

MISDIRECTED CENTRAL VENOUS CATHETER

Scenario 1. A 23 yr old patient with antepartum hemorrhage was taken to OT for Caesarean section. She had profuse bleeding on table  but could be controlled following delivery of baby, with blood transfusion and colloids. The chest on auscultation revealed fine basal creps and she had persistent hypotension.A central venous catheter was introduced through the right internal jugular vein. Confirmation of placement done by aspiration for free flow and rapid infusion of fluids.But the free flow was not obseved at a catheter length of 14 cm or13 cm but free flow observed at 11 cm.The patient remained ventilated and was shifted to the icu and CXR was  taken The tip of the catheter appeared to be in the right subclavian vein  with a slight angulation. A repeat procedure was deferred as the patient had coagulopathy and that the clinical confirmatory tests are satisfactory. The next day afternoon patient was complaining of raspiratory distress with tachypnea and pain on right side of chest. Auscultation revealed absent breath sounds on right side  with dullness on percussion. A repeat CXR showed  displacement of catheter tip, with massive pleural effusion on the right side which was drained subsequently.

Monday, June 21, 2010

ARTIFICIAL BLOOD, HOPE FOR THE FUTURE?

A sigh of relief, the tension is relieved as the gynaecologist took the baby out with great  difficulty through the incision. The  indication for caesarean section was severe fetal distress and the OT atmosphere has now turned pleasant as the paediatrician reported that the APGAR score is 9. The anaesthesiologist is busy preparing  oxytocin infusion and sedation.The patient who was given regional anaesthesia is now anxious to see her baby.But the enjoyment did not last long as the surgical team noted profuse bleeding with a flabby uterus not responding to ergometrine or oxytocin.A request for issuing blood was  sent to blood bank but the request was returned ,stating that the husband refused any kind of blood transfusion as he is a strict Jehovah's witness which he didn't mention at the time of taking the consent!

 Jehovah's witnesses, a fellowship of more than 1 million americans, object to the administration of blood in any form for any indication.This objection is based on "THE HOLY BIBLE"  Acts 15:28,29 which states "For it has seemed good to the Holy Spirit and to us to lay on you no greater burden than these requirements: that you abstain from what has been sacrificed to idols, and from blood, and from what has been strangled, and from sexual immorality. If you keep yourselves from these, you will do well. Farewell.” According to them blood removed from the body should be discarded "You should pour it upon the ground as water"  (Deuteronomy 12:24.)This makes pre operative blood conservation technique like preoperative phlebotomy and storage impractical
The search for an oxygen carrying blood substitute started with world war II as the military realized the difficulties of whole blood transport and storage.Subsequently several trials were made to bring out an ideal blood substitute using chemicals which can carry oxygen.
1)Perfluorocarbon compounds:Of the various substances that carry or facilitate the transport of oxygen the perfluorocarbons gave the most promising results.They were created by replacing H2 atoms of hydrocarbons with flurine. This was following the first real success in  "fluid breathing system" proposed by Leland Clark in 1966. He found that oxygen and carbondioxide are very much soluble in fluorocarbon liquids and can be used for artificial ventilation of the lungs which are immersed in these compounds where satisfactory oxygen uptake  and giving out of CO2 takes place by the alveoli through the liquid media, in the absence of external oxygen supply.He performed his experiment in anaesthetised rat where the animal is paralysed intubated and immersed in PF liquid.After bubbling oxygen through the liquid this is pumped into the animal's lungs and recirculated. Most of the animals kept in the fluid for upto an hour survived for several weaks. Subsequently trials were made in humans during war time.               Figure: Demonstrating a living mouse immersed  in  perfluorocarbon compound along with a goldfish.
  • Fluosol-DA was the most notable compound among PFCs, regarded as a first generation PFC.It contained perfluorodecalin and perfluorotripropylamine emulsified with Pluronic F-68  It was approved by the FDA for use in percutaneous transluminal coronary angioplasty initially but was subsequently withdrawn(see below)
  • They have high affinity for oxygen approximately 10-20 times greater than plasma.The  oxygen content of PFCs  is directly proportional to oxygen partial pressure and are most efficient as oxygen carriers at a partial pressure of more than 300mmHg, which limited their use, as patients needed high inspired oxygen concentration. A short intravascular half life, unstable at extreme temperatures, Low oxygen carrying capacity ,poor shelf life and adverse effects such as acute complement activation and disruption of pulmonary surfactant, all lead to their withdrawal  from the market. But still these compounds have found some place in "Liquid ventilation" of lungs in ARDS.