When I first arrived in Aden in late January we could leave the hospital where we live and work to go out into the city. That all changed drastically, almost overnight, when the fighting and bombings began just over two weeks ago. Since then we have been on lockdown inside the hospital.

Our surgical project now regularly deals with influxes of war wounded people. Since the fighting started we’ve treated 580 patients. The worst day was 26 March, the day after the Saudi-led air strikes began, when 110 injured people came in for emergency care. One of the major roads to the hospital is now blocked, so there may be people out there who have been injured but cannot get through to us. We’d like to send more ambulances out into the city to pick people up, but at times it is too dangerous.

Most of our patients are young men, but we’ve also treated women and children. Almost all of them have been injured by gunshots, snipers or shrapnel. I’ve seen men in their 20s come in with their legs blown off – I’ve never seen injuries like it before. We’ve also had children who have been badly injured while they were playing. We are a surgical project, but at times people have injuries to their heads or necks that are too serious for us to treat so we have to refer them elsewhere.

Our small team of six international staff work 24/7 with our team of 140 Yemeni staff – they are the lifeblood of the hospital. Although it can be dangerous for our local staff to come to work, so many do every day. Often it is too insecure for them to leave, so we try to take people back home in an ambulance or they stay overnight at the hospital.

The atmosphere is tense and very stressful. We hear fighting outside the hospital and bombs falling a little further away. We take it in turns to sleep for a couple of hours at a time, though it is often on the floor in the corridor – a safe distance from the windows in our rooms.

We desperately need more international staff to come and relieve us. Our surgeon, anaesthetist and head nurse are exhausted. A backup team are stuck in Djibouti.

The airports have closed so the only way into Aden is by boat, but there are serious restrictions in place at the port. We also need more drugs and medical supplies. Unless we get supplies through in the coming days, we will run out.

We don’t ask how our patients were wounded – our business is only to provide medical care. I do ask where in the city people were injured so that I can try to piece together where heavy fighting is taking place and where is unsafe for our drivers to go.

Some of those who come to us for treatment will doubtless be fighters, but they respect our rules to leave the conflict at the door and know that we treat people from both sides. Our neutrality and impartiality are the best protection we have, and enables us to keep the hospital open. Because we have been providing free surgical care here since 2011, people have a good understanding of what we are trying to do. For the moment the hospital is relatively safe and we have not been affected by the insecurity, but of course at times we worry that we are in danger.

There are fighters everywhere and we don’t know who is controlling the area outside the hospital – it seems to change on an hourly basis.

When a large influx of patients arrive there is no time to think – we have to be strong, focused, and keep a distance so that we can do our jobs. It is when we sit down to debrief and make a list of the cases that have come in that day that we can reflect a little more on what is happening.

• Valerie Pierre is the project coordinator at Médecins Sans Frontières’ surgical project in Aden