Hydrostatic pressure irrigation system in hysteroscopic surgeries - JS Afonso

This link was last updated on July 31, 2007.

This article should be cited as:

Afonso JS. Hydrostatic pressure irrigation system in hysteroscopic surgeries. In: I Congresso Brasileiro de Endoscopia Ginecológica e Obstétrica. Belo Horizonte, 2000. Anais do I Congresso Brasileiro de Endoscopia Ginecológica e Obstétrica. Belo Horizonte, 2000. Available in: http://www.histeroscopia.med.br/. Access in:

keywords: hysteroscopy, hydrostatic pressure, hysteroscopic surgeries, resectoscope.




The objective of this project is to produce a system to simulate in vivo surgery and that will allow the measurement of the alterations of the corresponding intra-uterine pressure (IUCP) and of flow rate to be taken (FR).


The irrigator, with an opening at the top, was placed in such a way that the  superior liquid level was 190.4cm above the medial line of the rubber ball,  which corresponds to 140 mmHg (10 mmHg = 13,6 cm of water, Fig.1 e Fig 2).


Fig. 1 


Fig. 2



The 26 F resectoscope (Storz) and the analogic momanometer (Wan Ross) were connected to the rubber ball, which had an opening on each pole (Fig. 3).


The resectoscope set comprised the object of work, internal sheath, external sheath, electrical loop and Hamou II optics (4mm). The IUPC and FR alterations were measured together with progressive outflow obstruction and then suction was used (a 60 ml syringe). A digital stopwatch and an ml-graded recipient were  used to measure FR. An  outflow pressure, with a fully open system, was exerted only by the resectoscope set according to Iglesias, 1975 (Fig. 4).

Fig. 4

The measurements of the IUPC variations with the level of the liquid above 176.8 cm and 136 cm were taken again.

Hamou's Hysteromater was regulated to 100 mmHg pressure  (and then to 150 mmHg) and the flow was of 300 ml/min,  full outflow obstruction and IUPC being carried out. 


The alteration of the IUPC at 190.4 cm was from 82 mmHg to 140 mmHg. At 176.8 the IUPC went from 76 mmHg to 130 mmHg (Diagram 1). At 136 cm the IUPC went from 58 mmHg to 100 mmHg.

At 190.4 cm the maximum  FR, without the use of suction, was of 547.4 ml/min and went steadily down  with  progressive obstruction (Diagram 2). With the use of suction FR goes up and IUPC goes down.

Hamou's  Hysteromater, after full outflow obstruction stabilises in seconds  IUPC with permanent variations of 10 mmHg (Diagram 3).


For a proper distension of the uterine cavity an intra-uterine pressure of between 70 e 80 mmHg is necessary. By placing the irrigator with the superior initial level of the liquid of 190,4 cm and final of about 176.8 cm we will have intra-uterine pressure at the levels desired for the performance of the hysteroscopic surgery (Fig. 5).

Fig. 5

When there are remains of tissue blocking the outflow, intra-uterine pressure will not go beyond 140 mmHg and the tendency is for  inflow to go to zero. 

Pressure and flow rate variations will happen even with electronic systems with in and out sensors. With the use of suction flow rate will increase and intra-uterine pressure will fall. The IUPC is altered with the hydrostatic pressure (inflow pressure) and with the pressure gradient difference (inflow and outflow pressure).


Hamou JE. Hysteroscopy and Microcolpohysteroscopy: Text and Atlas. Conn., USA: Appleton Lange, 1991

Iglesias JJ et al. New Iglesias resectoscope with continuous irrigation, simultaneous suction and low intravesical pressure. J. Urol 114:929, 1975.