Correspondence

CORRESPONDENCE – Inadvertent administration of intrathecal protamine during caesarian section.

Nouman I. Alvi, MRCA, FCARCSI

Consultant and Faculty, Department of Anesthesiology, Aga Khan University, Karachi Pakistan  ; E-mail: nouman.alvi@aku.edu

A pregnant lady was planned to undergo an elective cesarean section under spinal block. After routine monitoring a trainee resident performed the block under the consultant supervision. As per standard practice, the Operating Department Practitioner (ODP) read aloud the contents of ampoule as bupivacaine, the trainee resident voiced the same and gestured to read the label and proceeded to inject the solution into the subarachnoid space. The consultant moved forward to check the ampoule when he noticed that the ampoule actually read Protamine and not bupivacaine. Meanwhile the resident had injected nearly 1.5 ml of the solution. The procedure was abandoned; surgeon informed and patient was sensitively informed of the error. Patient’s vital signs and cardiotocography (CTG) were observed closely, first in the theatre and then in the recovery area. She was watched for any signs of dyspnea, rashes or syncope. Her vitals remained stable, no untoward signs and symptoms were noted and patient was discharged after four hours from recovery area. Patient was examined by anesthesia team in the obstetric ward after 24 hours and found to be entirely non symptomatic and without any new abnormal physical finding. Subsequently, she had another spinal performed and had a normal baby was delivered.

Protamine is a compound of basic arginine amino acids.1,5 This is a precursor  of Nitric Oxide ( NO) and leads to NO induced direct vasodilation and suppression of sympathetic outflow.5  This is believed to lead to hypotension and bradycardia. 5 It is derived from sperm of salmon fish.1 It has high clearance rate in the blood. It is metabolized by the proteolytic enzymes in the cerebrospinal fluid (CSF).2,3 Protamine is conventionally used as an antagonist of heparin. It is combined with insulin as   formulation of delayed release compound.4  It is administered very slowly because it can lead to anaphylactoid and anaphylactic reactions.1

This incident highlighted a safety issue in our daily practice. Reading aloud the name of an injectable drug by two individuals is a standard safety practice routine but unfortunately it becomes just a ritual when “eyes do not see what the tongue is saying”. A subsequent interview with both ODP and the trainee highlighted this anomaly. The consultant reflected that he should have visually confirmed the ampoule after listening, rather than hearing the statement of two colleagues. As for the trainee resident, inaction or staying silent should not be assumed as a nod of approval by the resident. In the real world, drug accidents are a real and very possible risk. Fortunately for everyone, this drug accident did not lead to an adverse event. It has helped us identify and address safety issues after root cause analysis.

REFERENCES

  1. CalveyTN and Williams NE. Principles and Practice of Pharmacology for Anaesthetists, Fifth Edition ed. Singapore : Blackwell Publishing; 2008.
  2. Hamada Y1, Kameyama Y, Narita H, Benson KT, Goto H. Protamine after heparin produces hypotension resulting from decreased sympathetic outflow secondary to increased nitric oxide in the central nervous system. Anesth Analg 2005;100(1):33-7. [PubMed]
  3. Cuzner M L, Davison A N, Rudge P. Proteolytic enzyme activity of blood leukocytes and cerebrospinal fluid in multiple sclerosis.  Ann Neurol 1978;4:337-344. [PubMed]
  4. Chapman LF, Wolff HG. Studies of Proteolytic Enzymes in Cerebrospinal Fluid: Capacity of Incubated Mixtures of Cerebrospinal Fluid and Plasma Proteins to Form Vasodilator Substances That Contract the Isolated Rat Uterus. AMA Arch Intern Med 1959;103:86-94. [PubMed]
  5. Balhorn R. The   protamine family of sperm nuclear proteins. Genome Biology 2007;8:227. [PubMed][Free Full Text]