Category : Correspondence

Prevention of air embolism during hysteroscopy

Rahil Singh*, Rajeev Sharma*, Aruna Jain**, Sunil Sinha**, Tanvir Samra***

*Assistant Professor; **Professor

Department of Anaesthesia and Intensive Care, Lady Hardinge Medical College, Shaheed Bhagat Singh Road, New Delhi-110001 (India)

***Assistant Professor, Department of Anaesthesia and Intensive Care, Post Graduate Institute of Medical Education & Research (PGIMER), Sector 12 Chandigarh-160012 (India)

Correspondence: DrTanvir Samra, Assistant Professor, PGIMER, Sector 12,Chandigarh-160012(India); E-mail: drtanvirsamra@yahoo.co.in

Key words: Venous air embolism; Hysteroscopy

Citation: Singh R, Sharma R, Jain A, Sinha S, Samra T. Prevention of air embolism during hysteroscopy (Correspondence). Anaesth Pain & Intensive Care 2014;18(4):469-70

Air embolism is a potentially catastrophic complication of operative hysteroscopy. Its incidence varies from 10-50% depending on the detection method used but prevalence of subclinical embolism may be as high as 100%.1,2 We recently witnessed this complication in two patients and we briefly describe the preventive and therapeutic measures needed in such cases.

Twenty eight year old, ASA PS 1 female was scheduled for hysteroscopic guided Copper–T (Cu-T) removal. She underwent the same procedure previously, which was unsuccessful as only one limb of the Cu-T could be removed. Routine monitors were attached and anaesthesia was induced with IV propofol and fentanyl followed by insertion of No. 3 Proseal™ laryngeal mask airway. Anaesthesia was maintained with spontaneous breathing of oxygen (O2), nitrous oxide (N2O) and sevoflurane. The patient was placed in lithotomy position with 20⁰ Trendelenburg position. Hysteroscopy was performed using normal saline pressurized by pressure infuser on 3 lit non-collapsible bottle. Cu-T was firmly embedded in the myometrium and removed after vigorous extraction following which the patient developed pulseless electrical activity (PEA), with no recordable EtCO2 and blood pressure. No heart sounds were heard but ECG showed sinus rhythm with heart rate of 90 bpm. Patient was immediately turned supine and administered 100% O2 after trachea was intubated. Cardiopulmonary resuscitation was done for 45 min but patient could not be revived.

A thirty five year old, ASA PS 1 patient with history of infertility was posted for diagnostic hysteroscopy. Standard monitors were attached and anaesthesia was induced with IV fentanyl, thiopentone and rocuronium. Trachea was intubated with cuffed 7.5 endotracheal tube and anaesthesia was maintained with isoflurane/O2/N2O. Hysteroscopy was performed using normal saline through mechanical pump (EndoMet™). Patient was placed in lithotomy + slight Trendelenburg position. After 30 min there was a sudden fall in SpO2, EtCO2 and heart rate (100→40 bpm). Blood pressure was unrecordable. 100% O2, atropine (0.6 mg) and adrenaline (1 mg) were administered. Patient was placed in Durant’s position, right internal jugular vein was cannulated and 100 ml blood mixed with air was aspirated. Dopamine infusion was started. Subsequently SpO2 and EtCO2 levels improved, blood pressure rose to 90/60 mmHg with pulse of 120 bpm. Patient was shifted to ICU; inotropes were gradually tapered over the next three hours. Trachea was extubated after 24 hours with no neurological deficit. Later surgeons admitted to have noticed several bubbles in the hysteroscope tubing which were not evacuated.

Box 1: Practice guidelines for perioperative management of patients scheduled for hysterolaparoscopy3,4,5

  1. Hysteromat set and tubing should be free of air and changed with every patient. All sites of connections should be leak proof.
    1. Priming fluid should be free of air bubbles. One person should keep a watch on tubings and alert if air bubbles are noted.
    2. Intravenous set tubings should be prefilled with fluid.
    3. Mechanised pumps should be used for irrigating fluid.
    4. Y-connector should be attached on in flow line to allow for change of bottles without letting the air  enter the system
  2. Height of fluid bottles should be restricted to less than one meter above the patient.
  3. Use of external pressure infusers should be avoided.
  4. Pressure inside the uterine cavity to be kept <100 mm Hg during hysteroscopy.
  5. Intra-abdominal pressure should be less than 10-12 mm Hg.
  6. To avoid repeated insertions and removals of the hysteroscope.
  7. Trivial injury of the uterus increases risk of embolism and thus the anaesthesiologist to be informed and extra vigilance kept
  8. Transthoracic echocardiography TTE/ Transesophageal echocardiography (TEE) probe to be used if available. TEE has the maximum sensitivity, they can also identify right to left shunting and even 0.5 ml of air bubbles can be detected.
  9. Central venous catheters, arterial cannulas, resuscitation equipment and drugs to be kept ready
  10. Avoid the use of N2O and steep Trendelenburg position
  11. Intravascular volume to be optimized.
  12. Positive pressure ventilation.
  13. Preoperative use of osmotic dilators (nonporous patients, prior cervical surgery)
  14. Intracervical injection of dilute vasopressin helps in reducing the risk of embolism.
  15. Dilatation and curettage to be performed after hysteroscopy

Prolonged surgical time and traumatic removal of the Cu-T leading to uterine perforation and opening of venous channels along with negative intrathoracic pressure during spontaneous breathing could have precipitated venous air embolism in the first patient. Use of external pressure infusers without Y connectors were the contributory factors. The volume of air embolism in the second patient was less and managed promptly by insertion of a central venous line and aspiration of air with patient in Durant’s position. Y connector with mechanical pump was used in the second case but air bubbles had entered the tubing during change of fluids which was later on acknowledged by the OT technician and the surgeons.

Venous air embolism is preventable and every institute should issue practice guidelines for peri-operative management of patients undergoing hysterolaparoscopy (Table 1).

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