Thermal blanket with surgical access

In a pneumatic, disposable, temperature control blanket having a periphery defined by a head end, a foot end, and lateral sides and having a central region, the blanket being formed by an envelope defined by an upper thermoplastic flexible air impervious sheet and a lower thermoplastic flexible sheet heat sealed together at the blanket periphery, a pneumatic flow chamber defined between the upper and lower sheets, an air inlet port defined in the envelope in communication with the flow chamber for supplying pressurized air thereto, a plurality of spaced orifices defined in the lower sheet in communication with the flow chamber to convey temperature controlled air to the patient, the improvement comprising, an elongated central primary slit defined in the blanket envelope central region having opposite edges and extending through the upper and lower sheets, said central slit being located between the blanket lateral sides and substantially parallel thereto and not intersecting the blanket periphery, first and second secondary elongated slits defined in the envelope each having opposite edges and extending through the upper and lower sheets, said secondary slits transversely intersecting said central slit at spaced locations along its length and forming a flap portion in the envelope between said secondary slit portions which may be folded back to provide access through the envelope, and flexible seals sealing said slits' opposite edges to prevent air loss at said slits.