382 lines
14 KiB
Python
382 lines
14 KiB
Python
import logging
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from datetime import datetime, timezone
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from typing import Optional, List
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import struct
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from schemas import NormalizedVitals
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logger = logging.getLogger(__name__)
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# Contec CMS7000PLUS / CMS8000 / CMS9200PLUS OBX identifiers mapping to schema fields
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CONTEC_PARAM_MAP = {
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# Heart Rate / Pulse Rate
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"HR": "heart_rate",
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"HEART_RATE": "heart_rate",
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"ECG_HR": "heart_rate",
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"PR": "heart_rate",
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"PULSE_RATE": "heart_rate",
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"SPO2_PR": "heart_rate",
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"ECGHR": "heart_rate",
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"ECG-HR": "heart_rate",
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"PULSERATE": "heart_rate",
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# SpO2
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"SPO2": "spo2",
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"SAO2": "spo2",
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"SPO2_PCT": "spo2",
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"OXYGEN_SAT": "spo2",
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"SPO2_VAL": "spo2",
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"O2SAT": "spo2",
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# Blood Pressure (NIBP)
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"NIBP_SYS": "systolic_bp",
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"NIBP_DIA": "diastolic_bp",
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"NIBP_MEAN": "map_bp",
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"NIBP_MAP": "map_bp",
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"SYS": "systolic_bp",
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"DIA": "diastolic_bp",
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"MAP": "map_bp",
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"NBP_S": "systolic_bp",
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"NBP_D": "diastolic_bp",
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"NBP_M": "map_bp",
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"NIBP-S": "systolic_bp",
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"NIBP-D": "diastolic_bp",
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"NIBP-M": "map_bp",
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"BP_SYS": "systolic_bp",
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"BP_DIA": "diastolic_bp",
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"BP_MEAN": "map_bp",
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# Respiratory Rate
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"RESP": "respiratory_rate",
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"RESP_RATE": "respiratory_rate",
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"RR": "respiratory_rate",
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"BR": "respiratory_rate",
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"RESPRATE": "respiratory_rate",
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"RESP-RATE": "respiratory_rate",
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# Temperature
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"TEMP": "temperature",
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"TEMP1": "temperature",
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"TEMP2": "temperature",
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"T1": "temperature",
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"T2": "temperature",
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"BODY_TEMP": "temperature",
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"TEMP-1": "temperature",
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"TEMP-2": "temperature",
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"BODYTEMP": "temperature",
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}
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# Sentinel value used by Contec to mark an invalid/disconnected parameter
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INVALID_SENTINEL_U16 = 9999 # 0x270F
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INVALID_SENTINEL_F32 = 9999.0
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def safe_float(value: str) -> Optional[float]:
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try:
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return float(value)
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except (ValueError, TypeError):
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return None
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def is_valid_u16(val: Optional[int]) -> bool:
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return val is not None and val != INVALID_SENTINEL_U16
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def is_valid_f32(val: Optional[float]) -> bool:
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return val is not None and abs(val - INVALID_SENTINEL_F32) > 1.0
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def read_u16_le(buf: bytes, offset: int) -> Optional[int]:
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if offset + 2 <= len(buf):
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return struct.unpack_from('<H', buf, offset)[0]
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return None
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def read_f32_le(buf: bytes, offset: int) -> Optional[float]:
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if offset + 4 <= len(buf):
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return struct.unpack_from('<f', buf, offset)[0]
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return None
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def parse_contec_hl7_text(raw_text: str, client_ip: str) -> Optional[NormalizedVitals]:
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"""
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Lightweight, native parser for Contec HL7 messages.
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Splits segments and fields manually, avoiding third-party library dependencies.
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"""
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try:
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# Strip MLLP framing if present (VT=0x0b, FS=0x1c, CR=0x0d)
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clean_text = raw_text.strip()
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if clean_text.startswith("\x0b"):
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clean_text = clean_text[1:]
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if "\x1c\x0d" in clean_text:
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clean_text = clean_text.split("\x1c\x0d")[0]
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# Split into segments by CR or LF
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segments = [seg.strip() for seg in clean_text.replace("\n", "\r").split("\r") if seg.strip()]
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if not segments or not segments[0].startswith("MSH"):
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return None
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# Parse MSH segment
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msh_fields = segments[0].split("|")
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device_id = msh_fields[2] if len(msh_fields) > 2 and msh_fields[2] else f"CMS7000_{client_ip}"
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patient_id = "UNKNOWN"
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vitals_dict = {
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"device_id": device_id,
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"patient_id": patient_id,
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"timestamp": datetime.now(timezone.utc),
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}
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found_any = False
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# Parse PID and OBX segments
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for seg in segments[1:]:
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fields = seg.split("|")
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if not fields:
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continue
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seg_name = fields[0]
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if seg_name == "PID":
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if len(fields) > 3 and fields[3]:
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patient_id = fields[3].split("^")[0]
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vitals_dict["patient_id"] = patient_id
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elif seg_name == "OBX":
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if len(fields) > 5:
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obs_id = fields[3].split("^")[0].strip().upper()
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obs_val = fields[5].strip()
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if not obs_val or obs_val == "---":
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continue
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val_float = safe_float(obs_val)
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if val_float is None:
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continue
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for param_key, mapped_field in CONTEC_PARAM_MAP.items():
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if obs_id == param_key or param_key in obs_id:
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vitals_dict[mapped_field] = val_float
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found_any = True
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logger.info(f"Parsed Contec HL7 Vital: {mapped_field} = {val_float} (from {obs_id})")
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break
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return NormalizedVitals(**vitals_dict) if found_any else None
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except Exception as e:
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logger.error(f"Error parsing Contec HL7 text: {e}")
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return None
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def _extract_vitals_block(data: bytes, offset: int, client_ip: str) -> Optional[NormalizedVitals]:
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"""
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Extract vitals from a Contec vitals block starting at the given offset.
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Known Contec CMS7000PLUS binary vitals block layout (confirmed from packet captures):
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PACKET TYPE B (header bytes [xx][00][04][46] or [xx][yy][04][46]):
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-----------------------------------------------------------------------
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Bytes 8-11 : float32 LE → NIBP Systolic (9999.0 = invalid)
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Bytes 12-15 : float32 LE → NIBP Diastolic (9999.0 = invalid)
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Bytes 16-19 : float32 LE → NIBP MAP (9999.0 = invalid)
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Bytes 20-23 : float32 LE → Temperature 1 (°C, 9999.0 = invalid)
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Bytes 24-27 : float32 LE → Temperature 2 (°C, 9999.0 = invalid)
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Vitals summary block (at data[offset] position, found by scanning for SpO2+HR pattern):
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Offset +0 : uint16 LE → SpO2 (%) (9999 = invalid)
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Offset +2 : uint16 LE → Heart Rate (bpm)(9999 = invalid, ECG not connected)
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Offset +4 : uint16 LE → Pulse Rate (bpm)(from SpO2 probe, also 9999 if invalid)
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Offset +6 : uint16 LE → (SpO2 alarm/threshold)
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Offset +8 : uint16 LE → (mode flags)
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Offset +10 : uint16 LE → NIBP Systolic (9999 = invalid)
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Offset +12 : uint16 LE → NIBP Diastolic (9999 = invalid)
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"""
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vitals_dict = {
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"device_id": f"CMS7000PLUS_{client_ip}",
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"patient_id": "UNKNOWN",
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"timestamp": datetime.now(timezone.utc),
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}
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found = False
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spo2 = read_u16_le(data, offset)
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hr_ecg = read_u16_le(data, offset + 2)
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hr_spo2 = read_u16_le(data, offset + 4)
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# SpO2 value: valid range 50–100
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if spo2 is not None and 50 <= spo2 <= 100:
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vitals_dict["spo2"] = float(spo2)
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found = True
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# Heart rate: prefer ECG HR; fall back to SpO2-derived PR if ECG invalid
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if is_valid_u16(hr_ecg) and 20 <= hr_ecg <= 300:
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vitals_dict["heart_rate"] = float(hr_ecg)
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found = True
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elif is_valid_u16(hr_spo2) and 20 <= hr_spo2 <= 300:
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vitals_dict["heart_rate"] = float(hr_spo2)
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found = True
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return NormalizedVitals(**vitals_dict) if found else None
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def _parse_float_vitals(data: bytes, base_offset: int, vitals_dict: dict) -> bool:
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"""
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Parse float32 vitals (NIBP, Temperature) from packet starting at base_offset.
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Returns True if any valid vitals found.
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"""
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found = False
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nibp_sys = read_f32_le(data, base_offset)
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nibp_dia = read_f32_le(data, base_offset + 4)
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nibp_map = read_f32_le(data, base_offset + 8)
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temp1 = read_f32_le(data, base_offset + 12)
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temp2 = read_f32_le(data, base_offset + 16)
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if nibp_sys is not None and is_valid_f32(nibp_sys) and 50.0 < nibp_sys < 300.0:
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vitals_dict["systolic_bp"] = round(nibp_sys, 1)
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found = True
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if nibp_dia is not None and is_valid_f32(nibp_dia) and 20.0 < nibp_dia < 200.0:
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vitals_dict["diastolic_bp"] = round(nibp_dia, 1)
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found = True
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if nibp_map is not None and is_valid_f32(nibp_map) and 20.0 < nibp_map < 250.0:
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vitals_dict["map_bp"] = round(nibp_map, 1)
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found = True
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if temp1 is not None and is_valid_f32(temp1) and 30.0 < temp1 < 45.0:
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vitals_dict["temperature"] = round(temp1, 1)
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found = True
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elif temp2 is not None and is_valid_f32(temp2) and 30.0 < temp2 < 45.0:
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vitals_dict["temperature"] = round(temp2, 1)
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found = True
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return found
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def _find_vitals_block_in_stream(data: bytes, client_ip: str) -> Optional[NormalizedVitals]:
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"""
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Scan the data stream for Contec CMS7000PLUS sub-packets.
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Contec packets follow this framing pattern:
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[len_lo] [len_hi] [04] [46] [sub_type] [00] [sub_len_lo] [00] ...payload...
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OR the data is a concatenation of multiple sub-packets separated by
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[xx][xx][04][47] (end marker?)
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The key is to find [04][46] marker bytes and parse the packet.
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"""
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vitals_dict = {
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"device_id": f"CMS7000PLUS_{client_ip}",
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"patient_id": "UNKNOWN",
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"timestamp": datetime.now(timezone.utc),
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}
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found_any = False
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# Scan through the buffer looking for [04 46] packet markers
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i = 0
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while i < len(data) - 8:
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# Look for the [04][46] marker which is the packet type indicator
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if data[i + 2] == 0x04 and data[i + 3] == 0x46:
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pkt_len = struct.unpack_from('<H', data, i)[0] # little-endian length
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# Packet type B: small packets (< 600 bytes) with vitals summary
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# These have float32 NIBP values at offset +8 relative to packet start
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if 30 < pkt_len < 600 and i + 8 <= len(data):
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# Read float32 vitals at offsets 8, 12, 16, 20, 24 from packet start
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_parse_float_vitals(data, i + 8, vitals_dict)
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# Find the vitals summary block in this packet
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# It appears near the tail of the resp waveform data
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# The pattern we look for: SpO2 byte (50-100), followed by various u16 values
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# In packet B, the summary is 75 bytes before the end
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if pkt_len > 50:
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# The summary block is consistently found around offset 322 in 397-byte packets
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# Relative to packet start: around pkt_len - 75
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summary_offset = i + max(4, pkt_len - 80)
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if summary_offset + 10 < len(data):
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# Scan in the last ~100 bytes of the packet for SpO2 pattern
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scan_end = min(i + pkt_len, len(data) - 4)
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scan_start = max(i + 4, scan_end - 100)
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for j in range(scan_start, scan_end - 4, 2):
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spo2 = read_u16_le(data, j)
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hr = read_u16_le(data, j + 2)
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pr = read_u16_le(data, j + 4)
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# Check if this looks like [SpO2][HR/sentinel][PR]
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spo2_ok = spo2 is not None and 50 <= spo2 <= 100
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# HR can be 9999 (invalid/ECG disconnected) or valid 20-300
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hr_or_sentinel = hr is not None and (hr == INVALID_SENTINEL_U16 or 20 <= hr <= 300)
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pr_ok = pr is not None and (pr == INVALID_SENTINEL_U16 or 20 <= pr <= 300)
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if spo2_ok and hr_or_sentinel and pr_ok:
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vitals_dict["spo2"] = float(spo2)
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found_any = True
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# Use ECG HR if valid, else use SpO2 PR
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if hr is not None and hr != INVALID_SENTINEL_U16 and 20 <= hr <= 300:
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vitals_dict["heart_rate"] = float(hr)
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elif pr is not None and pr != INVALID_SENTINEL_U16 and 20 <= pr <= 300:
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vitals_dict["heart_rate"] = float(pr)
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logger.info(
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f"Parsed vitals block at offset {j}: "
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f"SpO2={spo2}, HR={hr}, PR={pr}"
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)
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break
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# Move past this packet
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i += max(pkt_len, 4)
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else:
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i += 1
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return NormalizedVitals(**vitals_dict) if found_any else None
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def parse_contec_binary_packet(data: bytes, client_ip: str) -> Optional[NormalizedVitals]:
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"""
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Decodes the Contec CMS7000PLUS proprietary binary protocol.
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The monitor sends two alternating TCP packets:
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- Packet A (991 bytes): ECG waveform + SpO2 waveform + vitals footer
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- Packet B (397 bytes): Resp waveform + vitals summary + param block
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Both have the structure: [len_lo][len_hi][04][46][subtype][00][sublen][00]...[payload]...
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"""
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try:
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return _find_vitals_block_in_stream(data, client_ip)
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except Exception as e:
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logger.error(f"Error parsing Contec binary packet: {e}")
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return None
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def parse_contec_data(raw_data: bytes, client_ip: str) -> Optional[NormalizedVitals]:
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"""
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Unified entry point for parsing data from a Contec CMS7000PLUS monitor.
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Attempts HL7 text parsing first, falling back to proprietary binary parsing.
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"""
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if not raw_data:
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return None
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# Attempt 1: HL7 Text Decoding
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try:
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text = raw_data.decode("utf-8", errors="ignore").strip()
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if "MSH" in text or "\x0bMSH" in text:
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vitals = parse_contec_hl7_text(text, client_ip)
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if vitals:
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return vitals
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except Exception:
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pass
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# Attempt 2: Binary Parsing (Contec proprietary protocol)
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vitals = parse_contec_binary_packet(raw_data, client_ip)
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if vitals:
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return vitals
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# Logging fallback
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logger.warning(
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f"Data packet from {client_ip} unrecognized. "
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f"Len: {len(raw_data)}, Hex head: {raw_data[:32].hex()}"
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)
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return None
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